Microbes isolated from Saline-Alkali Soil of Northern Ningxia ： insight on microbial diversity and antibacterial activity

Microbes isolated from Saline-Alkali Soil of Northern Ningxia ： insight on microbial diversity and antibacterial activity | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Microbes isolated from Saline-Alkali Soil of Northern Ningxia ： insight on microbial diversity and antibacterial activity Xiao-li Ma, Jing-jing Tian, Fan-fan Ding This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6277773/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Microbial secondary metabolites are important sources of drug lead compounds. However, due to the discovery of novel microbial resources and the blindness of traditional screening strategies, the number of drugs developed from traditional microorganisms is decreasing year by year. Microorganisms in special habitats have attracted more and more attention because of their unique growth and evolution conditions and stress-resistant genes, which can produce molecules with novel structures and unique pharmacological activities. In order to explore the diversity of microbial resources, 104 strains with certain morphological characteristics were isolated from special habitat saline-alkali soil in northern of Ningxia. The ITS and 16S rRNA sequences of those strains were sequenced and identified by genome extraction technology. Among them, 38 strains of fungi and 44 strains of bacteria were identified, including 36 strains of Streptomyces , 5 strains of Amycolatopsis , 1 strain of Cellulomonas , 1 strain of Bacillus and 1 strain of Aurysmus . Furthermore, the antibacterial activity of 44 strains of bacteria were studied. 36 strains of Actinomycetes with antibacterial activity were screened out, including 5 strains of Amycolatopsis and 31 strains of Streptomyces , with active strains accounting for 81.81%. Among the active strains, the secondary metabolites of 35 strains had significant antibacterial activity against Proteus vulgaris , 20 strains had obvious inhibitory activity against Staphylococcus aureus , and 14 strains had certain growth inhibitory activity against Candida albicans . The results showed that most of the microbial strains isolated from saline-alkali soil in northern Ningxia had strong antibacterial activity, and possess the potential for further exploring antibacterial active secondary metabolites. This study not only enriched the microbial resources in special habitats, but also laid a foundation for further isolation of antibacterial lead compounds from saline-alkali soil. Saline-alkali soil Microorganisms Actinomycetes Antibacterial activity Figures Figure 1 Figure 2 Figure 3 INTRODUCTION Natural products derived from microorganisms are an important source of new drug research and development. After the successful research and development of penicillin and streptomycin in the last century, the discovery of new antibiotics from microbial secondary metabolites entered a golden age 1 . Drugs with antibacterial, antiviral, antitumor and immunomodulatory effects have been developed from secondary metabolites of actinomycetes , especially Streptomyces 2 – 4 . However, in the past 40 years, the development speed of microbial drugs represented by new antibiotics has obviously slowed down. Since the beginning of the 21st century, only daptomycin and fidaxomicin are directly derived from microbial secondary metabolites among the 36 successfully marketed antibiotics 5 . In contrast, the emergence of multidrug-resistant antibiotics and pan-drug-resistant bacteria leads to millions of deaths from bacterial infections every year in the world, and 10 million people will die from drug-resistant bacteria infections in the world by 2050 6 . It can be seen that human beings are gradually entering the "post-antibiotic" era, and health problems are facing unprecedented challenges. Therefore, it is of great importence to find new active strains and mining new structural antibacterial active substances. Studies have shown that extreme environment leads to the biodiversity of microorganisms with unique biochemical mechanisms and metabolic pathways, and it is more likely to produce new bioactive substances with special mechanisms 7 . Saline-alkali soil has high pH, low content of organic matter and humus, poor nutrients and water permeability. In order to enhance the adaptability to harsh environment, soil microorganisms need to improve the harsh soil environment through self-regulation mechanism, and effectively increase the content of nutrient elements in soil. Therefore, soil microorganisms in saline-alkali soil have the characteristics of strong adaptability and rich species, and show special metabolic mechanism and strong salt-alkali tolerance 8 . It is reported that halophilic bacteria are one of the most abundant medicinal resources, which can produce a large number of stable and unique biomolecules, so they are regarded as an important source of new bioactive compounds 9 , 10 . The northern part of Yinchuan Plain in Ningxia (commonly known as Ningbei area) is seriously salinized due to climatic factors such as low precipitation and high evaporation. There are more than 120 thousand hectares of saline-alkali land, accounting for 54% of the cultivated land area in the region, which is an important source of microorganisms in saline-alkali habitats. In recent years, many scholars have studied saline-alkali soil, and most of them focus on agronomy and ecology 11 , 12 . There are few reports on new strains mining and secondary metabolite activity research of saline-alkali soil microorganisms. In this paper, the diversity and activity of microorganisms in saline-alkali soil in northern Ningxia were studied, which laid a foundation for further developing antibacterial active strain resources and excavating novel antibacterial active substances. MATERIALS AND METHODS Collection of samples Saline-alkali soil samples were collected in Yinchuan City, Ningxia Hui Autonomous Region (106 08 'E, 38 38' N). The pH of the soil samples was 9.21, and the salt content was 0.32%, belonging to moderately alkaline saline-alkali soil. The saline-alkali soil of 20 cm below the ground surface was taken in a sterile bag and sealed in a 4 ° C refrigerator. Soil samples were stored in the Key Laboratory of Chemical Engineering and Technology of State Ethnic Affairs Commission, North Minzu University. Isolation of strains Soil samples were removed from impurities and ground into powder to prepare gradient soil suspensions with concentration of 10 − 1 , 10 − 2 , 10 − 3 , 10 − 4 , and 10 − 5 . 0.5 ml of soil suspension was uniformly coated on Gao's No.1 culture plate containing 100 µg/mL of potassium dichromate (PDA medium containing 120 µ g/ml of antibiotics for fungi), and cultured at 30 ° C for 1–7 days. A single new strain was selected and marked on a blank plate, and then cultured at 30 ° C for one week to obtain pure strain. The resulting pure culture was stored in a sterile 50% glycerol-aqueous solution in-20 ° C refrigerator, and the inclined culture was stored in a 4 ° C refrigerator 13 . The strain was cultured at 30 ° C for one week to obtain a single colony, and the morphology of the colony was observed. The strain was imaged on a flat plate with pixel of 2,340 × 1,080 equipment. A 10 x 10 mm coverslip was inserted obliquely into the colony plate at 45 °, cultured at 30 ° C for 3–5 days. Then the coverslip was taken out and wiped clean with 75% alcohol, then placed under a biological optical microscope with magnification of 10 x 40 times to observe the morphology of the strain. Species identification and biodiversity analysis The strains were identified by ITS and 16S rRNA sequencing technology 14 . The gene sequence data were spliced by DNAMAN software, and uploaded to the database of National Center for Biotechnology Information (NCBI) for comparison. The species information with the greatest similarity with the sequences of the tested species was obtained as the identification results. Download the gene sequences of reference strains with high similarity, and compare the gene sequences of the strains and the reference strains in Clustal W tool by MEGA X software. Construct a phylogenetic tree between the comparison strains and the reference strains by Neighbor-Joining 15 . Screening of antimicrobial activity The bacteria pure strain on agar medium was screened by agar diffusion method to determined antimicrobial potency 16 . The microbial that used as indicator for the testing consists of Gram positives bacteria S. aureus (CGMCC1.6740), Gram negative bacteria P. vulgaris (CGMCC 1.1651) and fungi C. albicans (CMCC 98001). Choosing vancomycin hydrochloride, ofloxacin and amphotericin B as positive controls, and sterile water and dimethyl sulfoxide as blank controls. The standard antibacterial activity of the assay strain with concentration of 10 7 -10 8 CFU/mL was tested. Three kinds of assay strain solutions were absorbed and coated evenly in PDA medium and nutrient agar medium. Place the Oxford cup on the above medium, absorb 100 µL (0, 2.5, 5, 10, 20, 100, 200, 400, 600, 800, 1000 µg/mL) of positive control solution in Oxford cup, culture at 37 ° C for 2–3 days. The bacteriostatic circle was observed and measured, and the lowest drug concentration for inhibiting the growth of assay strain was selected as MIC value. The pure strain of bacteria was taken with sterile straws and put on the surface of medium agar with the microbial testing, and incubated in optimum temperature of each microbial testing. The inhibition zone was measured. RESULTS AND DISCUSSION Colony morphology 104 strains with certain morphological characteristics were isolated from saline-alkali soil in northern Ningxia, of which 44 strains of bacterium were shown in Fig. 1 . The colony shapes were different with each other, and the combination between colony and culture medium was firm and difficult to pick. The bacterial colony was opaque and the color was slightly different between the front and back ( Table S1 ). Among them, strains CF-001, CF-018 and CF-035 have smooth, moist and viscous surfaces. The strains CF-006, CF-007, CF-008, CF-016, CF-020 and CF-025 all metabolized obvious pigments. Through imaging observation under 10 × 40 bio-optical microscope, most strains have well-branched hyphae, which are dense, thin and uniform, and with obvious actinomycete hyphae characteristics (Fig. 2 ). Some hyphae of CF-017, CF-021 and CF-039 were hammer-shaped, and more sporangia were attached to the hyphae of CF-017 and CF-039. Fungal colonies are mostly characterized by large colonies, developed aerial hyphae, diverse colors and shapes ( Figure S1 ). Among them, strains AZ-014, AZ-015 and AZ-020 all metabolize green pigment, with obvious surface folds and firm combination with culture medium, which is difficult to pick. Strains BZ-005 and BZ-018 were yellow and brown, respectively, and their surfaces were powdery. Strains BZ-014 and BZ-015 were gray-white and dark green. Species identification and biodiversity analysis of strains The ITS and 16S rRNA gene sequences of the isolated strains were determined and uploaded to NCBI database for comparison. The results showed that 44 strains covered 5 genera of bacterial phylum, including 36 strains of Streptomyces , 5 strains of Amycolatopsis , 1 strain of Cellulomonas , 1 strain of Sporobacter and 1 strain of Aurysmus (Table 1 , Fig. 3 A). Streptomyces is the dominant species in the structural bacteria population of saline-alkali soil. The phylogenetic tree was constructed by 16S rRNA sequence, and the genetic relationship among the strains in this population was analyzed as shown in Fig. 3 B. Strains CF-037 and CF-022 are closely related, both of which are Streptomyces tenuifolium . Streptomyces purpureus CF-021 and Streptomyces anthocyanum CF-017 have high homology and belong to Streptomyces . Strains CF-012 and CF-013 are both Amycobacterium Colorado , which have close genetic relationship, but the colony morphology of strains is different. The phylogenetic relationship between Streptomyces alopectus AF-001 & AF-004, and Streptomyces tenuoflavus CF-027 & CF-026 are close. Streptomyces rubricus CF-020 and Streptomyces Venezuela CF-030 belong to the genus Streptomyces , and their evolutionary relationship is close and their homology is high through the branching of developmental trees. In the 60 strains of fungi, 38 strains were identified, covering 15 genera of Fungi. Among them, there are 1 strain of Nigrosabulum , 2 strains of Cordyceps , 1 strain of Penicillium , 8 strains of Chaetomium , 2 strains of Alternaria , 1 strain of Rhodotorula , 6 strains of Cladosporium , 2 strains of Aspergillus , 1 strain of Morphosporium , 1 strain of Vishniacozyma , 1 strain of Mucor , 3 strains of Cladosporium , 1 strain of Basidiomycete , 7 strains of Fusarium and 1 strain of Mucor ( Table S2 and Figure S2 ). Table 1 NCBI comparison of bacterial 16S rRNA sequences Strain No. DNA identification results Query Coverage Identities Sequence ID AF-001 S. calvus 98% 99.79% NR_115388.1 AF-002 S. calvus 98% 99.86% NR_115388.1 AF-003 S. calvus 98% 99.86% NR_115388.1 AF-004 S. calvus 99% 99.59% NR_115388.1 BF-001 Niallia nealsonii 99% 99.12% NR_044546.1 CF-001 S. caviscabies 99% 99.45% NR_114493.1 CF-002 A. coloradensis 98% 99.16% NR_114859.1 CF-003 S. chryseus 92% 100.00% NR_043353.1 CF-004 S. caviscabies 99% 99.45% NR_114493.1 CF-005 S. cyaneofuscatus 99% 99.65% NR_115383.1 CF-006 S. microflavus 99% 99.86% NR_103947.1 CF-007 S. microflavus 100% 99.79% NR_103947.1 CF-008 S. badius 99% 99.44% NR_043350.1 CF-009 S. microflavus 99% 99.72% NR_103947.1 CF-010 S. microflavus 98% 99.79% NR_103947.1 CF-011 S. microflavus 97% 99.65% NR_112408.1 CF-012 A. coloradensis 98% 99.02% NR_114859.1 CF-013 A. coloradensis 98% 99.09% NR_114859.1 CF-014 S. praecox 99% 99.79% NR_115437.1 CF-015 S. anthocyanicus 99% 99.03% NR_027222.1 CF-016 S. microflavus 99% 99.59% NR_103947.1 CF-017 S. anthocyanicus 98% 98.76% NR_027222.1 CF-018 A. atrinae 99% 100% NR_116743.1 CF-019 S. aurantiogriseus 98% 99.37% NR_115385.1 CF-020 S. lateritius 99% 99.93% NR_112277.1 CF-021 S. violaceoruber 98% 99.16% NR_041914.1 CF-022 S. microflavus 97% 99.72% NR_112408.1 CF-024 S. aurantiogriseus 98% 99.3% NR_115385.1 CF-025 S. cyaneofuscatus 99% 99.37% NR_115383.1 CF-026 S. microflavus 100% 99.79% NR_103947.1 CF-027 S. microflavus 99% 99.72% NR_103947.1 CF-028 S. bacillaris 97% 99.93% NR_041146.1 CF-029 S. microflavus 99% 99.72% NR_103947.1 CF-030 S. venezuelae 98% 99.72% NR_024764.1 CF-031 S. cavourensis 98% 99.72% NR_043851.1 CF-032 S. aurantiogriseus 98% 99.3% NR_115385.1 CF-033 S. caviscabies 99% 99.45% NR_114493.1 CF-034 S. aurantiogriseus 98% 99.37% NR_115385.1 CF-035 C. flavigena 100% 100% NR_074490.1 CF-036 S. anthocyanicus 99% 98.96% NR_027222.1 CF-037 S. microflavus 97% 99.72% NR_112408.1 CF-038 S. anthocyanicus 99% 99.03% NR_027222.1 CF-039 A. coloradensis 98% 99.09% NR_114859.1 CF-040 A. coloradensis 98% 99.09% NR_114859.1 Results of antibacterial activity of strains Standard control study Negative and positive controls of antibacterial activity screening were showed in Table 2 . The minimum inhibitory concentration (MIC) of norvancomycin hydrochloride against S. aureus was 10 µg/mL, the MIC of ofloxacin against P. vulgaris was 2.5 µg/mL, and the MIC of amphotericin B against C. albicans was 2.5 µg/mL. Table 2 Bacteriostatic circle determination results of bacteriostatic activity of strains Strain No. Bacteriostatic diameter/cm S. aureus P. vulgaris C. albicans AF-001 - 3.32 - AF-002 - 2.72 - AF-003 - 1.76 1.54 AF-004 - 3.24 - BF-001 - - - CF-001 - 2.58 - CF-002 1.72 2.8 - CF-003 2.52 2.87 - CF-004 - 3.11 - CF-005 2.67 4.23 3.2 CF-006 - 2.72 - CF-007 1.42 3.02 - CF-008 - 2.79 2.49 CF-009 1.93 3.07 - CF-010 4.5 3.63 2.12 CF-011 1.64 1.9 - CF-012 3.31 2.38 1.43 CF-013 2.15 3.02 1.29 CF-014 - 4.23 - CF-015 - 1.85 - CF-016 2.08 2.43 1.62 CF-017 - - - CF-018 - - - CF-019 - - - CF-020 - - - CF-021 - - - CF-022 3.45 3.1 1.1 CF-024 - 1.47 - CF-025 2.08 3.05 2 CF-026 - 3.77 - CF-027 2.62 3.22 - CF-028 2.48 3 2.1 CF-029 - 2.22 1.38 CF-030 - - 1.7 CF-031 2.43 2.7 1.1 CF-032 1.58 1.54 - CF-033 - 2.6 - CF-034 1.72 1.83 - CF-035 - - - CF-036 - - - CF-037 3.59 3.78 1.39 CF-038 - 1.58 - CF-039 2.24 2.91 - CF-040 1.27 2.03 - Antibacterial activity of strains The results of antibacterial activity screening of 44 strains are shown in Table 3 . There are 36 strains of active strains, accounting for 81.81%. All active strains are Actinomycetes , including 5 Amycolatopsis and 31 Streptomyces . The inhibition zones of 13 strains including CF-003, CF-005, CF-010 and CF-012 were all over 2cm in the experiment of S. aureus , larger than 1, 000 µg/mL of positive control (1.25 cm). Result indicated that the above strains had better activity against S. aureus under experimental conditions, which was stronger than the positive control demethylvancomycin hydrochloride. Among them, strains CF-012, CF-022 and CF-037 had remarkable inhibition effects, and the diameter of inhibition zone was all larger than 3 cm. Bacterial inhibition zones of 28 strains including AF-001, AF-002, AF-004 were all over 2cm in test of P. vulgaris . Among them, the diameter of bacteriostatic zones of strains AF-001, AF-004, CF-004, CF-005, CF-007, CF-009, CF-010, CF-013, CF-014, CF-022, CF-025, CF-026, CF-027, CF-028 and CF-037 were more than 3 cm, which indicated that these strains had significant inhibitory activity against P. vulgaris . The antibacterial activity of AF-001, CF-005, CF-014, CF-026 and CF-037 was stronger than that of 400 µg/mL ofloxacin solution (3.3 cm). The antimicrobial activity test of C. albicans showed that the diameter of the inhibition zone of five strains including CF-005, CF-008 and CF-010 were more than 2cm, better than of amphotericin B at 100 µg/mL (1.8 cm). However, 9 strains such as AF-003, CF-012 and CF-013 showed moderate antifungal activity under these experimental conditions. Among all the strains, 10 strains of Actinomycetes , including CF-005, CF-010, CF-012, CF-013, CF-016, CF-022, CF-025, CF-028, CF-031 and CF-037, had inhibitory activity against the three indicator strains at the same time. It can be inferred that the secondary metabolites of those 10 strains have broad-spectrum antibacterial activity. The inhibition effect of other strains was not obvious under the test concentration. Screening results of strains against S. aureus and P. vulgaris are shown in Fig. 4 and Fig. 5 . There are 20 strains of Actinomycetes with obvious inhibitory activity against S. aureus , including 15 strains of Streptomyces and 5 strains of Amycolatopsis . 35 strains showed inhibitory activity against P. vulgaris , including 5 strains of Amycolatopsis and 30 strains of Streptomyces . The antibacterial secondary metabolites from Streptomyces and Amycolatopsis usually include β-lactams, aminoglycosides, macrolides, polypeptides and other compounds. Therefore, the above active strains may contain similar structures with good antibacterial effect against Gram-positive and Gram-negative bacteria. The strain plate diagram of the activity screening results of C. albicans is shown in Fig. 6 . Among the 44 strains, 14 strains had inhibitory activity against C. albicans , accounting for 31.82%. Among them, there are 2 strains of Amycolatopsis and 12 strains of Streptomyces . Antifungal secondary metabolites derived from Actinomycetes include polyenes, lipopeptides, cyclic peptides, glycolipids, etc. Active strains may metabolize antifungal compounds with the above structural types. The results of activity screening indicated that the secondary metabolites of Actinomycetes isolated from saline-alkali soil in northern Ningxia had varying degrees of inhibitory effects on gram-positive bacteria, gram-negative bacteria and fungi, and had the potential to develop new antibiotics, which was worthy of further study. CONCLUSION In order to cope with the rising antibiotic resistance, the development of novel lead compounds with antibacterial activity has become the focus of current medical research 17 . Microorganisms in special habitats evolve and grow in harsh conditions and extreme environments, which can produce secondary metabolites with unique structure and high activity, thus are widely concerned in the fields of industry, agriculture and medicine 18 – 21 . Studying microorganisms growing in saline-alkali soil with harsh environment and developing extreme-tolerant and extreme-tolerant microorganisms will play an important role in providing a new generation of microbial drugs, and the excavation of secondary metabolites will play an important role in dealing with antibiotic abuse and drug resistance. In this paper, 104 strains of microorganisms were isolated from saline-alkali soil in northern Ningxia with the diversity analysis and antibacterial activity screening. Research showed that the moderately saline-alkali soil is rich in microbial groups, including 5 genera of bacteria and 15 genera of the eumycota. The bacteria isolated were Streptomyces , Amycolatopsis , Cellulomonas , Bacillus and Agromyces . The 15 genera in the fungus phylum were Nigrosabulum , Cordyceps , Penicillium , Chaetomium , Alternaria , Rhodotorula , Cladosporium , Aspergillus , Mortierella , Vishniacozyma , Actinomucor , Sarocladium , Scolecobasidium , Fusarium and Mucor . Actinomycetes accounted for 93.18% of the isolated single colony bacteria. Actinomycetes have always been considered as an important source of bioactive lead compounds with new structures. Among the 44 strains obtained, 36 strains were Actinomycetes with different antibacterial activities against S. aureus , P. vulgaris or C. albicans . Among them, 10 strains have obvious inhibitory activity against the above three tested strains, and have the potential to develop new structure and good biological activity lead compounds. Ningxia located in the northwest of China had a large area of uncultivated saline-alkali soil which was caused by climatic factors. Studies have shown that these saline-alkali soils are rich in microorganisms and most of them have antibacterial biological activity. This study lays a foundation for exploring new antibacterial active substances from saline-alkali soil habitats in northern Ningxia, and will also provide strain resources and basic guarantee for developing new microbial drugs. Statements & Declarations Funding This work was supported by the Natural Science Foundation of Ningxia province (2023AAC03319). Competing Interests The authors have no relevant financial or non-financial interests to disclose. Author Contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Jing-jing Tian and Fan-fan Ding. The first draft of the manuscript was written by Xiao-li Ma and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Data Availability The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. References Bernal, F. A., Hammann, P. & Kloss, F. Natural products in antibiotic development: is the success story over? Current Opinion in Biotechnology 78 , doi:10.1016/j.copbio.2022.102783 (2022). Arunachalam Chinnathambi, S. H. S., Maged A. Al-Garadi, Milton Wainwright, Sulaiman Ali Alharbi. Marine actinomycetes：An endless source of potentially therapeutic novel secondary metabolites and other bioactive compounds. Journal of King Saud University-Science 35 , 102931 (2023). Ngamcharungchit, C., Chaimusik, N., Panbangred, W., Euanorasetr, J. & Intra, B. Bioactive Metabolites from Terrestrial and Marine Actinomycetes. Molecules 28 , doi:10.3390/molecules28155915 (2023). Selim, M. S. M., Abdelhamid, S. A. & Mohamed, S. S. Secondary metabolites and biodiversity of actinomycetes. J Genet. Eng. Biotechnol. 19 , 13, doi:10.1186/s43141-021-00156-9 (2021). Clatworthy, A. E., Pierson, E. & Hung, D. T. Targeting virulence: a new paradigm for antimicrobial therapy. Nat Chem Biol 3 , 541-548, doi:10.1038/nchembio.2007.24 (2007). Giono-Cerezo, S., Santos-Preciado, J. I., Morfín-Otero, M. D., Torres-López, F. J. & Alcántar-Curiel, M. D. Antimicrobial resistance. Its importance and efforts to control. Gac. Med. Mex. 156 , 171-178, doi:10.24875/gmm.M20000358 (2020). Sayed, A. M. et al. Extreme environments: microbiology leading to specialized metabolites. Journal of Applied Microbiology 128 , 630-657, doi:10.1111/jam.14386 (2020). Poli, A. et al. Microbial Diversity in Extreme Marine Habitats and Their Biomolecules. Microorganisms 5 , doi:10.3390/microorganisms5020025 (2017). Selvarajan, R., Sibanda, T., Tekere, M., Nyoni, H. & Meddows-Taylor, S. Diversity Analysis and Bioresource Characterization of Halophilic Bacteria Isolated from a South African Saltpan. Molecules 22 , doi:10.3390/molecules22040657 (2017). Salwan, R. & Sharma, V. Genomics of prokaryotic extremophiles to unfold the mystery of survival in extreme environments. Microbiological Research 264 , doi:10.1016/j.micres.2022.127156 (2022). Ke, Y. & Li, F. Study on Microbial Flora and Diversity in Saline-alkali Soil Improved for Different Years in Yinchuan Plain. Journal of Henan Agricultral Sciences 43 , 75-79 (2014). Kong, T., Zhang, D., Xu, H. & Wang, L. Microbial Ecological Characteristics of Alkaline-saline Lands and Its Amelioration Process: A Review. Soils 46 , 581-588 (2014). Hayakawa, M. et al. A SELECTIVE ISOLATION METHOD FOR ACTINOMADURA-VIRIDIS IN SOIL. Journal of Fermentation and Bioengineering 79 , 287-289, doi:10.1016/0922-338x(95)90619-b (1995). Yoon, S.-H. et al. Introducing EzBioCloud: a taxonomically united database of 16S rRNA gene sequences and whole-genome assemblies. International Journal of Systematic and Evolutionary Microbiology 67 , 1613-1617, doi:10.1099/ijsem.0.001755 (2017). Saitou, N. & Nei, M. THE NEIGHBOR-JOINING METHOD - A NEW METHOD FOR RECONSTRUCTING PHYLOGENETIC TREES. Molecular Biology and Evolution 4 , 406-425, doi:10.1093/oxfordjournals.molbev.a040454 (1987). Sun, J., Liu, H., Zhang, H. & Xie, Y. in 3rd International Conference on Biotechnology, Chemical and Materials Engineering (CBCME 2013). 485-489 (2014). Rahman, M. M. et al. An Overview of Antimicrobial Stewardship Optimization: The Use of Antibiotics in Humans and Animals to Prevent Resistance. Antibiotics-Basel 11 , doi:10.3390/antibiotics11050667 (2022). Mehta, R., Singhal, P., Singh, H., Damle, D. & Sharma, A. K. Insight into thermophiles and their wide-spectrum applications. 3 Biotech 6 , doi:10.1007/s13205-016-0368-z (2016). Schmid, A. K., Allers, T. & DiRuggiero, J. SnapShot: Microbial Extremophiles. Cell 180 , 818-+, doi:10.1016/j.cell.2020.01.018 (2020). Schultz, J. & Rosado, A. S. Extreme environments: a source of biosurfactants for biotechnological applications. Extremophiles 24 , 189-206, doi:10.1007/s00792-019-01151-2 (2020). Kochhar, N. et al. Perspectives on the microorganism of extreme environments and their applications. Current Research in Microbial Sciences 3 , doi:10.1016/j.crmicr.2022.100134 (2022). Figures 4-6 Figures 4-6 are not available with this version. Additional Declarations No competing interests reported. Supplementary Files SupplementaryFile.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6277773","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":433579369,"identity":"cb91093d-1702-4f69-bd30-82f115dd9821","order_by":0,"name":"Xiao-li Ma","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAnklEQVRIiWNgGAWjYFAC5sYHEEYC0VoYmw1I1tImQZoW3RmJbdWFOYcZ+NlzDBh+7iBCi9mZg223Z247zCDZ88aAsfcMMVqON7bd5gVqMbiRY8DM2EaMlsOMbcUgLfbEawHawgy2RYJoLWcONkvzbkvnkTjzrOBgL1FabiQf/My7zVqOvz1544OfxGiBAR4QcYAEDaNgFIyCUTAK8AEA/I80UsFfJGMAAAAASUVORK5CYII=","orcid":"","institution":"State Ethnic Affairs Commission, North Minzu University","correspondingAuthor":true,"prefix":"","firstName":"Xiao-li","middleName":"","lastName":"Ma","suffix":""},{"id":433579370,"identity":"aa9660ad-1e71-40c5-a042-58a700346898","order_by":1,"name":"Jing-jing Tian","email":"","orcid":"","institution":"State Ethnic Affairs Commission, North Minzu University","correspondingAuthor":false,"prefix":"","firstName":"Jing-jing","middleName":"","lastName":"Tian","suffix":""},{"id":433579371,"identity":"d41159cb-3e6c-4b5b-804c-5c51e6dd6848","order_by":2,"name":"Fan-fan Ding","email":"","orcid":"","institution":"State Ethnic Affairs Commission, North Minzu University","correspondingAuthor":false,"prefix":"","firstName":"Fan-fan","middleName":"","lastName":"Ding","suffix":""}],"badges":[],"createdAt":"2025-03-21 12:53:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6277773/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6277773/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":79722035,"identity":"3472f7dc-cdcd-4862-b84a-62476a80b1b4","added_by":"auto","created_at":"2025-04-02 02:37:02","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":906496,"visible":true,"origin":"","legend":"\u003cp\u003eColony morphology of 44 strains of bacteria\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6277773/v1/9e4244094d680f5365f46e98.png"},{"id":79722036,"identity":"d8a5d216-c5ae-4cb4-850e-18044ac7d1f8","added_by":"auto","created_at":"2025-04-02 02:37:02","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1062835,"visible":true,"origin":"","legend":"\u003cp\u003eMicromorphology of bacteria strains\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6277773/v1/70b9c480f963fbb628e58f47.png"},{"id":79722034,"identity":"7c2e0e28-2a78-499b-a424-57976d7e5671","added_by":"auto","created_at":"2025-04-02 02:37:02","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":81221,"visible":true,"origin":"","legend":"\u003cp\u003eScale diagram of various genera of bacteria (A) and Phylogenetic tree based 16S rRNA gene sequence (B)\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6277773/v1/00f4e39f29d34f53c12c7c25.png"},{"id":80313870,"identity":"72272168-d45a-4ae8-9930-22e4714a59e6","added_by":"auto","created_at":"2025-04-10 12:02:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3096385,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6277773/v1/bb6f7d36-3d83-45b3-99b3-d85d2d15354c.pdf"},{"id":79722051,"identity":"0f627174-2c4d-44b8-86fe-27a68ca22fa9","added_by":"auto","created_at":"2025-04-02 02:37:02","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":7030085,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryFile.docx","url":"https://assets-eu.researchsquare.com/files/rs-6277773/v1/89f2f3fbbb3e4a24674b04f8.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Microbes isolated from Saline-Alkali Soil of Northern Ningxia ： insight on microbial diversity and antibacterial activity","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eNatural products derived from microorganisms are an important source of new drug research and development. After the successful research and development of penicillin and streptomycin in the last century, the discovery of new antibiotics from microbial secondary metabolites entered a golden age\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. Drugs with antibacterial, antiviral, antitumor and immunomodulatory effects have been developed from secondary metabolites of \u003cem\u003eactinomycetes\u003c/em\u003e, especially \u003cem\u003eStreptomyces\u003c/em\u003e \u003csup\u003e\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. However, in the past 40 years, the development speed of microbial drugs represented by new antibiotics has obviously slowed down. Since the beginning of the 21st century, only daptomycin and fidaxomicin are directly derived from microbial secondary metabolites among the 36 successfully marketed antibiotics\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. In contrast, the emergence of multidrug-resistant antibiotics and pan-drug-resistant bacteria leads to millions of deaths from bacterial infections every year in the world, and 10\u0026nbsp;million people will die from drug-resistant bacteria infections in the world by 2050\u003csup\u003e6\u003c/sup\u003e. It can be seen that human beings are gradually entering the \"post-antibiotic\" era, and health problems are facing unprecedented challenges. Therefore, it is of great importence to find new active strains and mining new structural antibacterial active substances.\u003c/p\u003e \u003cp\u003eStudies have shown that extreme environment leads to the biodiversity of microorganisms with unique biochemical mechanisms and metabolic pathways, and it is more likely to produce new bioactive substances with special mechanisms\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. Saline-alkali soil has high pH, low content of organic matter and humus, poor nutrients and water permeability. In order to enhance the adaptability to harsh environment, soil microorganisms need to improve the harsh soil environment through self-regulation mechanism, and effectively increase the content of nutrient elements in soil. Therefore, soil microorganisms in saline-alkali soil have the characteristics of strong adaptability and rich species, and show special metabolic mechanism and strong salt-alkali tolerance \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. It is reported that halophilic bacteria are one of the most abundant medicinal resources, which can produce a large number of stable and unique biomolecules, so they are regarded as an important source of new bioactive compounds \u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. The northern part of Yinchuan Plain in Ningxia (commonly known as Ningbei area) is seriously salinized due to climatic factors such as low precipitation and high evaporation. There are more than 120 thousand hectares of saline-alkali land, accounting for 54% of the cultivated land area in the region, which is an important source of microorganisms in saline-alkali habitats. In recent years, many scholars have studied saline-alkali soil, and most of them focus on agronomy and ecology\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. There are few reports on new strains mining and secondary metabolite activity research of saline-alkali soil microorganisms. In this paper, the diversity and activity of microorganisms in saline-alkali soil in northern Ningxia were studied, which laid a foundation for further developing antibacterial active strain resources and excavating novel antibacterial active substances.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eCollection of samples\u003c/h2\u003e \u003cp\u003eSaline-alkali soil samples were collected in Yinchuan City, Ningxia Hui Autonomous Region (106 08 'E, 38 38' N). The pH of the soil samples was 9.21, and the salt content was 0.32%, belonging to moderately alkaline saline-alkali soil. The saline-alkali soil of 20 cm below the ground surface was taken in a sterile bag and sealed in a 4 \u0026deg; C refrigerator. Soil samples were stored in the Key Laboratory of Chemical Engineering and Technology of State Ethnic Affairs Commission, North Minzu University.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eIsolation of strains\u003c/h3\u003e\n\u003cp\u003eSoil samples were removed from impurities and ground into powder to prepare gradient soil suspensions with concentration of 10\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e, 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e, 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e, and 10\u0026thinsp;\u0026minus;\u0026thinsp;\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. 0.5 ml of soil suspension was uniformly coated on Gao's No.1 culture plate containing 100 \u0026micro;g/mL of potassium dichromate (PDA medium containing 120 \u0026micro; g/ml of antibiotics for fungi), and cultured at 30 \u0026deg; C for 1\u0026ndash;7 days. A single new strain was selected and marked on a blank plate, and then cultured at 30 \u0026deg; C for one week to obtain pure strain. The resulting pure culture was stored in a sterile 50% glycerol-aqueous solution in-20 \u0026deg; C refrigerator, and the inclined culture was stored in a 4 \u0026deg; C refrigerator\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe strain was cultured at 30 \u0026deg; C for one week to obtain a single colony, and the morphology of the colony was observed. The strain was imaged on a flat plate with pixel of 2,340 \u0026times; 1,080 equipment. A 10 x 10 mm coverslip was inserted obliquely into the colony plate at 45 \u0026deg;, cultured at 30 \u0026deg; C for 3\u0026ndash;5 days. Then the coverslip was taken out and wiped clean with 75% alcohol, then placed under a biological optical microscope with magnification of 10 x 40 times to observe the morphology of the strain.\u003c/p\u003e\n\u003ch3\u003eSpecies identification and biodiversity analysis\u003c/h3\u003e\n\u003cp\u003eThe strains were identified by ITS and 16S rRNA sequencing technology\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. The gene sequence data were spliced by DNAMAN software, and uploaded to the database of National Center for Biotechnology Information (NCBI) for comparison. The species information with the greatest similarity with the sequences of the tested species was obtained as the identification results. Download the gene sequences of reference strains with high similarity, and compare the gene sequences of the strains and the reference strains in Clustal W tool by MEGA X software. Construct a phylogenetic tree between the comparison strains and the reference strains by Neighbor-Joining\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\n\u003ch3\u003eScreening of antimicrobial activity\u003c/h3\u003e\n\u003cp\u003eThe bacteria pure strain on agar medium was screened by agar diffusion method to determined antimicrobial potency\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. The microbial that used as indicator for the testing consists of Gram positives bacteria \u003cem\u003eS. aureus\u003c/em\u003e (CGMCC1.6740), Gram negative bacteria \u003cem\u003eP. vulgaris\u003c/em\u003e (CGMCC 1.1651) and fungi \u003cem\u003eC. albicans\u003c/em\u003e (CMCC 98001). Choosing vancomycin hydrochloride, ofloxacin and amphotericin B as positive controls, and sterile water and dimethyl sulfoxide as blank controls. The standard antibacterial activity of the assay strain with concentration of 10\u003csup\u003e7\u003c/sup\u003e-10\u003csup\u003e8\u003c/sup\u003e CFU/mL was tested. Three kinds of assay strain solutions were absorbed and coated evenly in PDA medium and nutrient agar medium. Place the Oxford cup on the above medium, absorb 100 \u0026micro;L (0, 2.5, 5, 10, 20, 100, 200, 400, 600, 800, 1000 \u0026micro;g/mL) of positive control solution in Oxford cup, culture at 37 \u0026deg; C for 2\u0026ndash;3 days. The bacteriostatic circle was observed and measured, and the lowest drug concentration for inhibiting the growth of assay strain was selected as MIC value. The pure strain of bacteria was taken with sterile straws and put on the surface of medium agar with the microbial testing, and incubated in optimum temperature of each microbial testing. The inhibition zone was measured.\u003c/p\u003e"},{"header":"RESULTS AND DISCUSSION","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eColony morphology\u003c/h2\u003e \u003cp\u003e104 strains with certain morphological characteristics were isolated from saline-alkali soil in northern Ningxia, of which 44 strains of bacterium were shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The colony shapes were different with each other, and the combination between colony and culture medium was firm and difficult to pick. The bacterial colony was opaque and the color was slightly different between the front and back (\u003cb\u003eTable \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e\u003c/b\u003e). Among them, strains CF-001, CF-018 and CF-035 have smooth, moist and viscous surfaces. The strains CF-006, CF-007, CF-008, CF-016, CF-020 and CF-025 all metabolized obvious pigments. Through imaging observation under 10 \u0026times; 40 bio-optical microscope, most strains have well-branched hyphae, which are dense, thin and uniform, and with obvious actinomycete hyphae characteristics (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Some hyphae of CF-017, CF-021 and CF-039 were hammer-shaped, and more sporangia were attached to the hyphae of CF-017 and CF-039. Fungal colonies are mostly characterized by large colonies, developed aerial hyphae, diverse colors and shapes (\u003cb\u003eFigure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e\u003c/b\u003e). Among them, strains AZ-014, AZ-015 and AZ-020 all metabolize green pigment, with obvious surface folds and firm combination with culture medium, which is difficult to pick. Strains BZ-005 and BZ-018 were yellow and brown, respectively, and their surfaces were powdery. Strains BZ-014 and BZ-015 were gray-white and dark green.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSpecies identification and biodiversity analysis of strains\u003c/h3\u003e\n\u003cp\u003eThe ITS and 16S rRNA gene sequences of the isolated strains were determined and uploaded to NCBI database for comparison. The results showed that 44 strains covered 5 genera of bacterial phylum, including 36 strains of \u003cem\u003eStreptomyces\u003c/em\u003e, 5 strains of \u003cem\u003eAmycolatopsis\u003c/em\u003e, 1 strain of \u003cem\u003eCellulomonas\u003c/em\u003e, 1 strain of \u003cem\u003eSporobacter\u003c/em\u003e and 1 strain of \u003cem\u003eAurysmus\u003c/em\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). \u003cem\u003eStreptomyces\u003c/em\u003e is the dominant species in the structural bacteria population of saline-alkali soil. The phylogenetic tree was constructed by 16S rRNA sequence, and the genetic relationship among the strains in this population was analyzed as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB. Strains CF-037 and CF-022 are closely related, both of which are \u003cem\u003eStreptomyces tenuifolium\u003c/em\u003e. \u003cem\u003eStreptomyces purpureus\u003c/em\u003e CF-021 and \u003cem\u003eStreptomyces anthocyanum\u003c/em\u003e CF-017 have high homology and belong to \u003cem\u003eStreptomyces\u003c/em\u003e. Strains CF-012 and CF-013 are both \u003cem\u003eAmycobacterium Colorado\u003c/em\u003e, which have close genetic relationship, but the colony morphology of strains is different. The phylogenetic relationship between \u003cem\u003eStreptomyces alopectus\u003c/em\u003e AF-001 \u0026amp; AF-004, and \u003cem\u003eStreptomyces tenuoflavus\u003c/em\u003e CF-027 \u0026amp; CF-026 are close. \u003cem\u003eStreptomyces rubricus\u003c/em\u003e CF-020 and \u003cem\u003eStreptomyces Venezuela\u003c/em\u003e CF-030 belong to the genus \u003cem\u003eStreptomyces\u003c/em\u003e, and their evolutionary relationship is close and their homology is high through the branching of developmental trees. In the 60 strains of fungi, 38 strains were identified, covering 15 genera of Fungi. Among them, there are 1 strain of \u003cem\u003eNigrosabulum\u003c/em\u003e, 2 strains of \u003cem\u003eCordyceps\u003c/em\u003e, 1 strain of \u003cem\u003ePenicillium\u003c/em\u003e, 8 strains of \u003cem\u003eChaetomium\u003c/em\u003e, 2 strains of \u003cem\u003eAlternaria\u003c/em\u003e, 1 strain of \u003cem\u003eRhodotorula\u003c/em\u003e, 6 strains of \u003cem\u003eCladosporium\u003c/em\u003e, 2 strains of \u003cem\u003eAspergillus\u003c/em\u003e, 1 strain of \u003cem\u003eMorphosporium\u003c/em\u003e, 1 strain of \u003cem\u003eVishniacozyma\u003c/em\u003e, 1 strain of \u003cem\u003eMucor\u003c/em\u003e, 3 strains of \u003cem\u003eCladosporium\u003c/em\u003e, 1 strain of \u003cem\u003eBasidiomycete\u003c/em\u003e, 7 strains of \u003cem\u003eFusarium\u003c/em\u003e and 1 strain of \u003cem\u003eMucor\u003c/em\u003e (\u003cb\u003eTable S2 and Figure S2\u003c/b\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNCBI comparison of bacterial 16S rRNA sequences\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eStrain No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDNA identification results\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eQuery\u003c/p\u003e \u003cp\u003eCoverage\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIdentities\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSequence ID\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAF-001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eS. calvus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.79%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115388.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAF-002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eS. calvus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.86%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115388.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAF-003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eS. calvus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.86%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115388.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAF-004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eS. calvus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.59%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115388.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eBF-001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eNiallia nealsonii\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.12%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_044546.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. caviscabies\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.45%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_114493.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eA. coloradensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.16%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_114859.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. chryseus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e92%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100.00%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_043353.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. caviscabies\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.45%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_114493.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. cyaneofuscatus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.65%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115383.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-006\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.86%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_103947.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.79%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_103947.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. badius\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.44%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_043350.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-009\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.72%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_103947.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.79%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_103947.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e97%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.65%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_112408.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-012\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eA. coloradensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.02%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_114859.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eA. coloradensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.09%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_114859.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-014\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. praecox\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.79%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115437.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-015\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. anthocyanicus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.03%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_027222.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.59%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_103947.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. anthocyanicus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e98.76%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_027222.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eA. atrinae\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_116743.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. aurantiogriseus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.37%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115385.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. lateritius\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.93%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_112277.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. violaceoruber\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.16%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_041914.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e97%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.72%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_112408.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. aurantiogriseus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.3%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115385.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. cyaneofuscatus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.37%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115383.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-026\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.79%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_103947.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-027\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.72%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_103947.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-028\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. bacillaris\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e97%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.93%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_041146.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.72%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_103947.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-030\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. venezuelae\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.72%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_024764.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-031\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. cavourensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.72%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_043851.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-032\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. aurantiogriseus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.3%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115385.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-033\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. caviscabies\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.45%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_114493.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-034\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. aurantiogriseus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.37%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_115385.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-035\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eC. flavigena\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_074490.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-036\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. anthocyanicus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e98.96%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_027222.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-037\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. microflavus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e97%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.72%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_112408.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-038\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. anthocyanicus\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.03%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_027222.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-039\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eA. coloradensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.09%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_114859.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-040\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eA. coloradensis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e99.09%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNR_114859.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eResults of antibacterial activity of strains\u003c/h3\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eStandard control study\u003c/h2\u003e \u003cp\u003eNegative and positive controls of antibacterial activity screening were showed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The minimum inhibitory concentration (MIC) of norvancomycin hydrochloride against \u003cem\u003eS. aureus\u003c/em\u003e was 10 \u0026micro;g/mL, the MIC of ofloxacin against \u003cem\u003eP. vulgaris\u003c/em\u003e was 2.5 \u0026micro;g/mL, and the MIC of amphotericin B against \u003cem\u003eC. albicans\u003c/em\u003e was 2.5 \u0026micro;g/mL.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBacteriostatic circle determination results of bacteriostatic activity of strains\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eStrain No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eBacteriostatic\u0026nbsp;diameter/cm\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS.\u0026nbsp;aureus\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP. vulgaris\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eC.\u0026nbsp;albicans\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAF-001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAF-002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAF-003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.54\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAF-004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBF-001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-006\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-008\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.49\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-009\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-012\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.43\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.29\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-014\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-015\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-026\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-027\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-028\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.38\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-030\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-031\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-032\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-033\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-034\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-035\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-036\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-037\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.39\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-038\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-039\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCF-040\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eAntibacterial activity of strains\u003c/h2\u003e \u003cp\u003eThe results of antibacterial activity screening of 44 strains are shown in \u003cb\u003eTable\u0026nbsp;3\u003c/b\u003e. There are 36 strains of active strains, accounting for 81.81%. All active strains are \u003cem\u003eActinomycetes\u003c/em\u003e, including 5 \u003cem\u003eAmycolatopsis\u003c/em\u003e and 31 \u003cem\u003eStreptomyces\u003c/em\u003e. The inhibition zones of 13 strains including CF-003, CF-005, CF-010 and CF-012 were all over 2cm in the experiment of \u003cem\u003eS. aureus\u003c/em\u003e, larger than 1, 000 \u0026micro;g/mL of positive control (1.25 cm). Result indicated that the above strains had better activity against \u003cem\u003eS. aureus\u003c/em\u003e under experimental conditions, which was stronger than the positive control demethylvancomycin hydrochloride. Among them, strains CF-012, CF-022 and CF-037 had remarkable inhibition effects, and the diameter of inhibition zone was all larger than 3 cm. Bacterial inhibition zones of 28 strains including AF-001, AF-002, AF-004 were all over 2cm in test of \u003cem\u003eP. vulgaris\u003c/em\u003e. Among them, the diameter of bacteriostatic zones of strains AF-001, AF-004, CF-004, CF-005, CF-007, CF-009, CF-010, CF-013, CF-014, CF-022, CF-025, CF-026, CF-027, CF-028 and CF-037 were more than 3 cm, which indicated that these strains had significant inhibitory activity against \u003cem\u003eP. vulgaris\u003c/em\u003e. The antibacterial activity of AF-001, CF-005, CF-014, CF-026 and CF-037 was stronger than that of 400 \u0026micro;g/mL ofloxacin solution (3.3 cm). The antimicrobial activity test of \u003cem\u003eC. albicans\u003c/em\u003e showed that the diameter of the inhibition zone of five strains including CF-005, CF-008 and CF-010 were more than 2cm, better than of amphotericin B at 100 \u0026micro;g/mL (1.8 cm). However, 9 strains such as AF-003, CF-012 and CF-013 showed moderate antifungal activity under these experimental conditions. Among all the strains, 10 strains of \u003cem\u003eActinomycetes\u003c/em\u003e, including CF-005, CF-010, CF-012, CF-013, CF-016, CF-022, CF-025, CF-028, CF-031 and CF-037, had inhibitory activity against the three indicator strains at the same time. It can be inferred that the secondary metabolites of those 10 strains have broad-spectrum antibacterial activity. The inhibition effect of other strains was not obvious under the test concentration.\u003c/p\u003e \u003cp\u003eScreening results of strains against \u003cem\u003eS. aureus\u003c/em\u003e and \u003cem\u003eP. vulgaris\u003c/em\u003e are shown in \u003cb\u003eFig.\u0026nbsp;4\u003c/b\u003e and \u003cb\u003eFig.\u0026nbsp;5\u003c/b\u003e. There are 20 strains of \u003cem\u003eActinomycetes\u003c/em\u003e with obvious inhibitory activity against \u003cem\u003eS. aureus\u003c/em\u003e, including 15 strains of \u003cem\u003eStreptomyces\u003c/em\u003e and 5 strains of \u003cem\u003eAmycolatopsis\u003c/em\u003e. 35 strains showed inhibitory activity against \u003cem\u003eP. vulgaris\u003c/em\u003e, including 5 strains of \u003cem\u003eAmycolatopsis\u003c/em\u003e and 30 strains of \u003cem\u003eStreptomyces\u003c/em\u003e. The antibacterial secondary metabolites from \u003cem\u003eStreptomyces\u003c/em\u003e and \u003cem\u003eAmycolatopsis\u003c/em\u003e usually include β-lactams, aminoglycosides, macrolides, polypeptides and other compounds. Therefore, the above active strains may contain similar structures with good antibacterial effect against Gram-positive and Gram-negative bacteria.\u003c/p\u003e \u003cp\u003eThe strain plate diagram of the activity screening results of \u003cem\u003eC. albicans\u003c/em\u003e is shown in \u003cb\u003eFig.\u0026nbsp;6\u003c/b\u003e. Among the 44 strains, 14 strains had inhibitory activity against \u003cem\u003eC. albicans\u003c/em\u003e, accounting for 31.82%. Among them, there are 2 strains of \u003cem\u003eAmycolatopsis\u003c/em\u003e and 12 strains of \u003cem\u003eStreptomyces\u003c/em\u003e. Antifungal secondary metabolites derived from \u003cem\u003eActinomycetes\u003c/em\u003e include polyenes, lipopeptides, cyclic peptides, glycolipids, etc. Active strains may metabolize antifungal compounds with the above structural types.\u003c/p\u003e \u003cp\u003eThe results of activity screening indicated that the secondary metabolites of \u003cem\u003eActinomycetes\u003c/em\u003e isolated from saline-alkali soil in northern Ningxia had varying degrees of inhibitory effects on gram-positive bacteria, gram-negative bacteria and fungi, and had the potential to develop new antibiotics, which was worthy of further study.\u003c/p\u003e \u003c/div\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eIn order to cope with the rising antibiotic resistance, the development of novel lead compounds with antibacterial activity has become the focus of current medical research\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Microorganisms in special habitats evolve and grow in harsh conditions and extreme environments, which can produce secondary metabolites with unique structure and high activity, thus are widely concerned in the fields of industry, agriculture and medicine \u003csup\u003e\u003cspan additionalcitationids=\"CR19 CR20\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Studying microorganisms growing in saline-alkali soil with harsh environment and developing extreme-tolerant and extreme-tolerant microorganisms will play an important role in providing a new generation of microbial drugs, and the excavation of secondary metabolites will play an important role in dealing with antibiotic abuse and drug resistance.\u003c/p\u003e \u003cp\u003eIn this paper, 104 strains of microorganisms were isolated from saline-alkali soil in northern Ningxia with the diversity analysis and antibacterial activity screening. Research showed that the moderately saline-alkali soil is rich in microbial groups, including 5 genera of bacteria and 15 genera of the eumycota. The bacteria isolated were \u003cem\u003eStreptomyces\u003c/em\u003e, \u003cem\u003eAmycolatopsis\u003c/em\u003e, \u003cem\u003eCellulomonas\u003c/em\u003e, \u003cem\u003eBacillus\u003c/em\u003e and \u003cem\u003eAgromyces\u003c/em\u003e. The 15 genera in the fungus phylum were \u003cem\u003eNigrosabulum\u003c/em\u003e, \u003cem\u003eCordyceps\u003c/em\u003e, \u003cem\u003ePenicillium\u003c/em\u003e, \u003cem\u003eChaetomium\u003c/em\u003e, \u003cem\u003eAlternaria\u003c/em\u003e, \u003cem\u003eRhodotorula\u003c/em\u003e, \u003cem\u003eCladosporium\u003c/em\u003e, \u003cem\u003eAspergillus\u003c/em\u003e, \u003cem\u003eMortierella\u003c/em\u003e, \u003cem\u003eVishniacozyma\u003c/em\u003e, \u003cem\u003eActinomucor\u003c/em\u003e, \u003cem\u003eSarocladium\u003c/em\u003e, \u003cem\u003eScolecobasidium\u003c/em\u003e, \u003cem\u003eFusarium\u003c/em\u003e and \u003cem\u003eMucor\u003c/em\u003e. \u003cem\u003eActinomycetes\u003c/em\u003e accounted for 93.18% of the isolated single colony bacteria. \u003cem\u003eActinomycetes\u003c/em\u003e have always been considered as an important source of bioactive lead compounds with new structures. Among the 44 strains obtained, 36 strains were \u003cem\u003eActinomycetes\u003c/em\u003e with different antibacterial activities against \u003cem\u003eS. aureus\u003c/em\u003e, \u003cem\u003eP. vulgaris\u003c/em\u003e or \u003cem\u003eC. albicans\u003c/em\u003e. Among them, 10 strains have obvious inhibitory activity against the above three tested strains, and have the potential to develop new structure and good biological activity lead compounds.\u003c/p\u003e \u003cp\u003eNingxia located in the northwest of China had a large area of uncultivated saline-alkali soil which was caused by climatic factors. Studies have shown that these saline-alkali soils are rich in microorganisms and most of them have antibacterial biological activity. This study lays a foundation for exploring new antibacterial active substances from saline-alkali soil habitats in northern Ningxia, and will also provide strain resources and basic guarantee for developing new microbial drugs.\u003c/p\u003e"},{"header":"Statements \u0026 Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Natural Science Foundation of Ningxia province (2023AAC03319).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Jing-jing Tian and Fan-fan Ding. The first draft of the manuscript was written by Xiao-li Ma and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBernal, F. A., Hammann, P. \u0026amp; Kloss, F. Natural products in antibiotic development: is the success story over? \u003cem\u003eCurrent Opinion in Biotechnology\u003c/em\u003e \u003cstrong\u003e78\u003c/strong\u003e, doi:10.1016/j.copbio.2022.102783 (2022).\u003c/li\u003e\n\u003cli\u003eArunachalam Chinnathambi, S. H. S., Maged A. Al-Garadi, Milton Wainwright, Sulaiman Ali Alharbi. Marine actinomycetes：An endless source of potentially therapeutic novel secondary metabolites and other bioactive compounds. \u003cem\u003eJournal of King Saud University-Science\u003c/em\u003e \u003cstrong\u003e35\u003c/strong\u003e, 102931 (2023).\u003c/li\u003e\n\u003cli\u003eNgamcharungchit, C., Chaimusik, N., Panbangred, W., Euanorasetr, J. \u0026amp; Intra, B. Bioactive Metabolites from Terrestrial and Marine Actinomycetes. \u003cem\u003eMolecules\u003c/em\u003e \u003cstrong\u003e28\u003c/strong\u003e, doi:10.3390/molecules28155915 (2023).\u003c/li\u003e\n\u003cli\u003eSelim, M. S. M., Abdelhamid, S. A. \u0026amp; Mohamed, S. S. Secondary metabolites and biodiversity of actinomycetes. \u003cem\u003eJ Genet. Eng. Biotechnol.\u003c/em\u003e \u003cstrong\u003e19\u003c/strong\u003e, 13, doi:10.1186/s43141-021-00156-9 (2021).\u003c/li\u003e\n\u003cli\u003eClatworthy, A. E., Pierson, E. \u0026amp; Hung, D. T. Targeting virulence: a new paradigm for antimicrobial therapy. \u003cem\u003eNat Chem Biol\u003c/em\u003e \u003cstrong\u003e3\u003c/strong\u003e, 541-548, doi:10.1038/nchembio.2007.24 (2007).\u003c/li\u003e\n\u003cli\u003eGiono-Cerezo, S., Santos-Preciado, J. I., Morf\u0026iacute;n-Otero, M. D., Torres-L\u0026oacute;pez, F. J. \u0026amp; Alc\u0026aacute;ntar-Curiel, M. D. Antimicrobial resistance. Its importance and efforts to control. \u003cem\u003eGac. Med. Mex.\u003c/em\u003e \u003cstrong\u003e156\u003c/strong\u003e, 171-178, doi:10.24875/gmm.M20000358 (2020).\u003c/li\u003e\n\u003cli\u003eSayed, A. M.\u003cem\u003e et al.\u003c/em\u003e Extreme environments: microbiology leading to specialized metabolites. \u003cem\u003eJournal of Applied Microbiology\u003c/em\u003e \u003cstrong\u003e128\u003c/strong\u003e, 630-657, doi:10.1111/jam.14386 (2020).\u003c/li\u003e\n\u003cli\u003ePoli, A.\u003cem\u003e et al.\u003c/em\u003e Microbial Diversity in Extreme Marine Habitats and Their Biomolecules. \u003cem\u003eMicroorganisms\u003c/em\u003e \u003cstrong\u003e5\u003c/strong\u003e, doi:10.3390/microorganisms5020025 (2017).\u003c/li\u003e\n\u003cli\u003eSelvarajan, R., Sibanda, T., Tekere, M., Nyoni, H. \u0026amp; Meddows-Taylor, S. Diversity Analysis and Bioresource Characterization of Halophilic Bacteria Isolated from a South African Saltpan. \u003cem\u003eMolecules\u003c/em\u003e \u003cstrong\u003e22\u003c/strong\u003e, doi:10.3390/molecules22040657 (2017).\u003c/li\u003e\n\u003cli\u003eSalwan, R. \u0026amp; Sharma, V. Genomics of prokaryotic extremophiles to unfold the mystery of survival in extreme environments. \u003cem\u003eMicrobiological Research\u003c/em\u003e \u003cstrong\u003e264\u003c/strong\u003e, doi:10.1016/j.micres.2022.127156 (2022).\u003c/li\u003e\n\u003cli\u003eKe, Y. \u0026amp; Li, F. Study on Microbial Flora and Diversity in Saline-alkali Soil Improved for Different Years in Yinchuan Plain. \u003cem\u003eJournal of Henan Agricultral Sciences\u003c/em\u003e \u003cstrong\u003e43\u003c/strong\u003e, 75-79 (2014).\u003c/li\u003e\n\u003cli\u003eKong, T., Zhang, D., Xu, H. \u0026amp; Wang, L. Microbial Ecological Characteristics of Alkaline-saline Lands and Its Amelioration Process: A Review. \u003cem\u003eSoils\u003c/em\u003e \u003cstrong\u003e46\u003c/strong\u003e, 581-588 (2014).\u003c/li\u003e\n\u003cli\u003eHayakawa, M.\u003cem\u003e et al.\u003c/em\u003e A SELECTIVE ISOLATION METHOD FOR ACTINOMADURA-VIRIDIS IN SOIL. \u003cem\u003eJournal of Fermentation and Bioengineering\u003c/em\u003e \u003cstrong\u003e79\u003c/strong\u003e, 287-289, doi:10.1016/0922-338x(95)90619-b (1995).\u003c/li\u003e\n\u003cli\u003eYoon, S.-H.\u003cem\u003e et al.\u003c/em\u003e Introducing EzBioCloud: a taxonomically united database of 16S rRNA gene sequences and whole-genome assemblies. \u003cem\u003eInternational Journal of Systematic and Evolutionary Microbiology\u003c/em\u003e \u003cstrong\u003e67\u003c/strong\u003e, 1613-1617, doi:10.1099/ijsem.0.001755 (2017).\u003c/li\u003e\n\u003cli\u003eSaitou, N. \u0026amp; Nei, M. THE NEIGHBOR-JOINING METHOD - A NEW METHOD FOR RECONSTRUCTING PHYLOGENETIC TREES. \u003cem\u003eMolecular Biology and Evolution\u003c/em\u003e \u003cstrong\u003e4\u003c/strong\u003e, 406-425, doi:10.1093/oxfordjournals.molbev.a040454 (1987).\u003c/li\u003e\n\u003cli\u003eSun, J., Liu, H., Zhang, H. \u0026amp; Xie, Y. in \u003cem\u003e3rd International Conference on Biotechnology, Chemical and Materials Engineering (CBCME 2013).\u003c/em\u003e 485-489 (2014).\u003c/li\u003e\n\u003cli\u003eRahman, M. M.\u003cem\u003e et al.\u003c/em\u003e An Overview of Antimicrobial Stewardship Optimization: The Use of Antibiotics in Humans and Animals to Prevent Resistance. \u003cem\u003eAntibiotics-Basel\u003c/em\u003e \u003cstrong\u003e11\u003c/strong\u003e, doi:10.3390/antibiotics11050667 (2022).\u003c/li\u003e\n\u003cli\u003eMehta, R., Singhal, P., Singh, H., Damle, D. \u0026amp; Sharma, A. K. Insight into thermophiles and their wide-spectrum applications. \u003cem\u003e3 Biotech\u003c/em\u003e \u003cstrong\u003e6\u003c/strong\u003e, doi:10.1007/s13205-016-0368-z (2016).\u003c/li\u003e\n\u003cli\u003eSchmid, A. K., Allers, T. \u0026amp; DiRuggiero, J. SnapShot: Microbial Extremophiles. \u003cem\u003eCell\u003c/em\u003e \u003cstrong\u003e180\u003c/strong\u003e, 818-+, doi:10.1016/j.cell.2020.01.018 (2020).\u003c/li\u003e\n\u003cli\u003eSchultz, J. \u0026amp; Rosado, A. S. Extreme environments: a source of biosurfactants for biotechnological applications. \u003cem\u003eExtremophiles\u003c/em\u003e \u003cstrong\u003e24\u003c/strong\u003e, 189-206, doi:10.1007/s00792-019-01151-2 (2020).\u003c/li\u003e\n\u003cli\u003eKochhar, N.\u003cem\u003e et al.\u003c/em\u003e Perspectives on the microorganism of extreme environments and their applications. \u003cem\u003eCurrent Research in Microbial Sciences\u003c/em\u003e \u003cstrong\u003e3\u003c/strong\u003e, doi:10.1016/j.crmicr.2022.100134 (2022).\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Figures 4-6","content":"\u003cp\u003eFigures 4-6 are not available with this version.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Saline-alkali soil, Microorganisms, Actinomycetes, Antibacterial activity","lastPublishedDoi":"10.21203/rs.3.rs-6277773/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6277773/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMicrobial secondary metabolites are important sources of drug lead compounds. However, due to the discovery of novel microbial resources and the blindness of traditional screening strategies, the number of drugs developed from traditional microorganisms is decreasing year by year. Microorganisms in special habitats have attracted more and more attention because of their unique growth and evolution conditions and stress-resistant genes, which can produce molecules with novel structures and unique pharmacological activities. In order to explore the diversity of microbial resources, 104 strains with certain morphological characteristics were isolated from special habitat saline-alkali soil in northern of Ningxia. The ITS and 16S rRNA sequences of those strains were sequenced and identified by genome extraction technology. Among them, 38 strains of fungi and 44 strains of bacteria were identified, including 36 strains of \u003cem\u003eStreptomyces\u003c/em\u003e, 5 strains of \u003cem\u003eAmycolatopsis\u003c/em\u003e, 1 strain of \u003cem\u003eCellulomonas\u003c/em\u003e, 1 strain of \u003cem\u003eBacillus\u003c/em\u003e and 1 strain of \u003cem\u003eAurysmus\u003c/em\u003e. Furthermore, the antibacterial activity of 44 strains of bacteria were studied. 36 strains of \u003cem\u003eActinomycetes\u003c/em\u003e with antibacterial activity were screened out, including 5 strains of \u003cem\u003eAmycolatopsis\u003c/em\u003e and 31 strains of \u003cem\u003eStreptomyces\u003c/em\u003e, with active strains accounting for 81.81%. Among the active strains, the secondary metabolites of 35 strains had significant antibacterial activity against \u003cem\u003eProteus vulgaris\u003c/em\u003e, 20 strains had obvious inhibitory activity against \u003cem\u003eStaphylococcus aureus\u003c/em\u003e, and 14 strains had certain growth inhibitory activity against \u003cem\u003eCandida albicans\u003c/em\u003e. The results showed that most of the microbial strains isolated from saline-alkali soil in northern Ningxia had strong antibacterial activity, and possess the potential for further exploring antibacterial active secondary metabolites. This study not only enriched the microbial resources in special habitats, but also laid a foundation for further isolation of antibacterial lead compounds from saline-alkali soil.\u003c/p\u003e","manuscriptTitle":"Microbes isolated from Saline-Alkali Soil of Northern Ningxia ： insight on microbial diversity and antibacterial activity","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-02 02:36:57","doi":"10.21203/rs.3.rs-6277773/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ab732aa6-f7e5-4685-972d-57b5e88b2908","owner":[],"postedDate":"April 2nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-04-10T11:38:22+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-02 02:36:57","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6277773","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6277773","identity":"rs-6277773","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}