Phylogenetic characterization of culturable bacterial diversity associated with the mucus and tissue of the coral Acropora digitifera from the Gulf of Mannar
Phylogenetic characterization of culturable bacterial diversity associated with the mucus and tissue of the coral Acropora digitifera from the Gulf of Mannar
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DOI：
10.1111/j.1574-6941.2009.00723.x
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发表时间：
2009-09-01
影响因子：
4.2
通讯作者：
Pandian, Shunmugiah Karutha
中科院分区：
文献类型：
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作者：
Nithyanand, Paramasivam;Pandian, Shunmugiah Karutha
珊瑚被认为是海洋的热带雨林，在整个珊瑚结构中蕴藏着丰富的不同细菌种群。在本研究中，我们试图对马纳尔湾珊瑚（Acropora digitalfera）粘液和组织中相关的可培养细菌群体进行表征。从培养的粘液和组织分离物中扩增出16S rRNA基因。结合限制性内切酶进行扩增核糖体DNA限制性内切分析，以确定细菌的多态性群，在珊瑚粘液中产生19个不同的群，在珊瑚组织中产生17个不同的群。基于16S rRNA基因序列全序列的系统发育分析表明，大多数分离的细菌属于厚壁菌门（Firmicutes），其次是γ变形菌门（Gammaproteobacteria）和放线菌门（Actinobacteria）。对其抑菌活性进行了研究，粘液分离株的抑菌活性为25%，组织分离株的抑菌活性为48%。本研究发现珊瑚黏液和珊瑚组织中均存在放线菌，放线菌具有较高的抗病原体活性。这项研究首次证明了珊瑚中存在的放线菌也具有潜在的抗菌活性。到目前为止，这一点一直被忽视，这表明，除了粘液，珊瑚组织内的细菌可能会保护珊瑚宿主免受病原体的侵害。
Corals, considered the rainforests of the oceans, harbour an abundance of different bacterial populations throughout the coral structure. In the present study we attempted to characterize the cultivable bacterial population associated within the mucus and tissue of the coral Acropora digitifera from the Gulf of Mannar. 16S rRNA gene was amplified from the cultured mucus and tissue isolates. Amplified ribosomal DNA restriction analysis, performed with a combination of restriction enzymes to determine the polymorphic groups of bacteria, generated 19 distinct groups in the coral mucus and 17 distinct groups in the coral tissue. Phylogenetic analyses based on the full-length sequences of 16S rRNA gene sequences showed that the majority of bacterial isolates belonged to the group Firmicutes, followed by Gammaproteobacteria and Actinobacteria. On investigating their antimicrobial activity, mucus isolates showed about 25% activity and tissue isolates showed 48% activity. This study revealed the presence of actinomycetes in both the coral mucus and the coral tissue, which had high activity against pathogens. This study, for the first time, demonstrates that actinomycetes existing within corals also have potential antibacterial activity. This has been overlooked so far, and indicates that, in addition to mucus, bacteria within the tissue of corals might defend the coral host against pathogens.