Diversity of cultivable protease-producing bacteria and their extracellular proteases associated to scleractinian corals
Diversity of cultivable protease-producing bacteria and their extracellular proteases associated to scleractinian corals
复制标题
可培养的产蛋白酶细菌及其与石珊瑚相关的胞外蛋白酶的多样性。
DOI：
10.7717/peerj.9055
复制
发表时间：
2020-05-06
期刊：
影响因子：
2.7
通讯作者：
Chen, Biao
中科院分区：
文献类型：
--
作者：
Su, Hongfei;Xiao, Zhenlun;Chen, Biao
产酶细菌在海洋环境中降解有机氮起着至关重要的作用。然而，细菌和胞外蛋白酶的多样性很少得到解决，特别是在珊瑚礁群落中。本研究从鹿回头边缘礁7属珊瑚中分离到136株胞外蛋白酶产生菌，并对其产酶类型进行了研究。与分枝珊瑚或叶状珊瑚相比，巨大的珊瑚拥有更多可培养的产蛋白酶细菌。可培养产酶细菌的丰度达到106cfu g(-1)的珊瑚。16S rRNA基因序列的系统发育分析表明，分离到的菌株隶属于24个属，其中20个对应于变形杆菌门和变形杆菌门。从所有珊瑚样品中检出芽孢杆菌和非芽孢杆菌。此外，弧菌和假弧菌在块状或叶状珊瑚Platygyra和Montipora中最常见。相比之下，仅在一个分离物中鉴定出11个属。几乎所有的细菌胞外蛋白酶都是丝氨酸蛋白酶或金属蛋白酶，45.83%的菌株还能释放半胱氨酸或天冬氨酸蛋白酶。这些酶对不同底物具有不同的水解力。这项研究代表了对可培养的产蛋白酶细菌及其胞外蛋白酶在硬珊瑚中的多样性的新见解。
Protease-producing bacteria play a vital role in degrading organic nitrogen in marine environments. However, the diversity of the bacteria and extracellular proteases has seldom been addressed, especially in communities of coral reefs. In this study, 136 extracellular protease-producing bacterial strains were isolated from seven genera of scleractinian corals from Luhuitou fringing reef, and their protease types were characterized. The massive coral had more cultivable protease-producing bacteria than branching or foliose corals. The abundance of cultivable protease-producing bacteria reached 10 6 CFU g(-1) of coral. Phylogenetic analysis of 16S rRNA gene sequences revealed that the isolates were assigned to 24 genera, from which 20 corresponded to the phyla Firmicutes and Proteobacteria. Bacillus and Fictibacillus were retrieved from all coral samples. Moreover, Vibrio and Pseudovibrio were most prevalent in massive or foliose coral Platygyra and Montipora. In contrast, 11 genera were each identified in only one isolate. Nearly all the extracellular proteases from the bacteria were serine proteases or metalloproteases; 45.83% of isolates also released cysteine or aspartic proteases. These proteases had different hydrolytic ability against different substrates. This study represents a novel insight on the diversity of cultivable protease-producing bacteria and their extracellular proteases in scleractinian corals.