| 摘要: |
| 海洋环境中存在着大量未被培养和利用的微生物资源。本研究对一份南海沉积物样品采用不同培养温度、盐度、pH、样品稀释倍数和营养浓度条件进行可培养细菌的多样性研究。经过16S rRNA基因序列分析，获得825株菌分属于5个门，8个纲，17个目，26个科，57个属。分离到最多的属级类群为芽胞杆菌属（Bacillus）。通过不同培养条件的分离实验发现，厚壁菌类群在4 °C~60 °C、0%~15%盐度、pH 5~8及不同的样品稀释倍数和营养浓度实验条件中均为优势培养类群，具有广泛的环境适应性，但2~200的样品稀释倍数可以大大减少分离培养基中厚壁菌的数量。放线菌类群在4 °C低温和0%NaCl添加条件下的可培养多样性较高，同时pH 6和寡营养培养基有助于分离获得稀有放线菌类群。另外，本研究发现新物种资源的获取几率分别在寡营养培养基、5%~10%较高盐度和60°C高温培养有所增加。分离获得的5个主要细菌门类分别为厚壁菌门（Firmicutes，86%）、放线菌门（Actinobacteria，13%）、变形菌门（Proteobacteria，1%）、拟杆菌门（Bacteroidetes）和异常球菌-栖热菌门（Deinococcus-Thermus）。本研究共分离得到29株潜在新种，分别属于芽胞杆菌纲（Bacilli）、放线菌纲（Actinobacteria）、酸微菌纲（Acidimicrobiia）、嗜热油菌纲（Thermoleophilia）、红色杆菌纲（Rubrobacteria）和异常球菌纲（Deinococci）。海洋环境微生物新类群、海洋放线菌稀有类群等微生物新资源的选择性分离培养提供了有效的方法和方案，为后期的深入开展打下良好的基础。 |
| 关键词: 南海沉积物 培养条件 可培养细菌多样性 |
| DOI：10.14188/j.ajsh.2020.05.008 |
| 分类号:Q93 |
| 基金项目:国家自然科学基金(41576143)；中国科学院青年创新促进会人才项目(2016307) |
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| Selective isolation of bacteria from marine sedimentary environment by different culture conditions |
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HE Yuanqiu1,2, LI Cun1,2, CHEN Rouwen1,2, CUI Linqing1,2, TIAN Xinpeng1
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1.Key laboratory of Tropical Marine Bio-resources and Ecology， South China Sea Institute of Oceanology， Chinese Academy of Sciences， Guangzhou 510301， Guangdong， China;2.University of Chinese Academy of Sciences， Beijing 100049， China
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| Abstract: |
| A large number of uncultured bacterial resources exist in the marine environments. In this study， different incubation conditions， including temperatures， salinities， pH， sample dilution ratios and nutrient concentrations， were used to analyze the diversity of culturable bacteria in a sediment sample collected from South China Sea. A total of 825 bacterial strains were obtained and identified by 16S rRNA gene sequencing， and distributed in 5 phyla， 8 classes， 17 orders， 26 families and 57 genera. The results showed that strains in phylum Firmicutes especially in genus Bacillus were the dominant culturable bacteria in all incubating conditions， including temperature from 4 °C-60 °C， 0%-15% NaCl salinity， pH 5-8， different sample dilution ratios and nutrient concentrations， revealing that this group had the wide marine environmental adaptability， but 2-200 sample dilution ratios showed the significant decrease of the Firmicutes strain number. The diversity of culturable Actinobacteria strains was higher under 4°C incubation and 0% NaCl salinity. Meanwhile， incubation at pH 6 or a oligotrophic condition was conducive to increase the cultivable rate of rare Actinobacteria. Oligotrophic medium， 5%-10% NaCl salinity and 60 °C incubation temperature were conductive to obtain novel species candidates. Proportions of all the strains in five phyla were Firmicutes（86%）， Actinobacteria（13%）， Proteobacteria（1%）， Bacteroidetes and Deinococcus-Thermus. A total of 29 potentially new species were isolated， including 6 classes of Bacilli， Actinobacteria， Acidimicrobiia， Thermoleophilia， Rubrobacteria and Deinococci. This study provides the effective methods for the selectivity of novel microbial resources and rare marine Actinobacteria， and lays the foundation for further research of marine microbial resources. |
| Key words: South China Sea sediment cultural condition culturable bacterial diversity |
