Webster Nicole S, Xavier Joana R, Freckelton Marnie, Motti Cherie A, Cobb Rose
Australian Institute of Marine Science, PMB 3 Townsville Mail Centre, Qld 4810, Australia.
Environ Microbiol. 2008 Dec;10(12):3366-76. doi: 10.1111/j.1462-2920.2008.01734.x. Epub 2008 Sep 8.
The microbial community composition in affected and unaffected portions of diseased sponges and healthy control sponges of Aplysina aerophoba was assessed to ascertain the role of microbes in the disease process. Sponge secondary metabolites were also examined to assess chemical shifts in response to infection. The microbial profile and aplysinimine levels in unaffected tissue near the lesions closely reflected those of healthy sponge tissue, indicating a highly localized disease process. DGGE detected multiple sequences that were exclusively present in diseased sponges. Most notably, a Deltaproteobacteria sequence with high homology to a coral black band disease strain was detected in all sponge lesions and was absent from all healthy and unaffected regions of diseased sponges. Other potential pathogens identified by DGGE include an environmental Cytophaga strain and a novel Epsilonproteobacteria strain with no known close relatives. The disease process also caused a major shift in prokaryote community structure at a very high taxonomic level. Using 16S rRNA gene sequence analysis, only the diseased sponges were found to contain sequences belonging to the Epsilonproteobacteria and Firmicutes, and there was a much greater number of Bacteroidetes sequences within the diseased sponges. In contrast, only the healthy sponges contained sequences corresponding to the cyanobacteria and 'OP1' candidate division, and the healthy sponges were dominated by Chloroflexi and Gammaproteobacteria sequences. Overall bacterial diversity was found to be considerably higher in diseased sponges than in healthy sponges. These results provide a platform for future cultivation-based experiments to isolate the putative pathogens from A. aerophoba and perform re-infection trials to define the disease aetiology.
对患有一种疾病的食气管鳃海绵（Aplysina aerophoba）患病和未患病部分以及健康对照海绵的微生物群落组成进行了评估，以确定微生物在疾病过程中的作用。还检测了海绵次生代谢产物，以评估感染后的化学变化。病变附近未受影响组织中的微生物谱和海兔胺水平与健康海绵组织的情况密切反映，表明疾病过程高度局限。变性梯度凝胶电泳（DGGE）检测到多个仅存在于患病海绵中的序列。最值得注意的是，在所有海绵病变中都检测到一个与珊瑚黑带病菌株具有高度同源性的δ变形菌序列，而在患病海绵的所有健康和未受影响区域均未发现该序列。通过DGGE鉴定出的其他潜在病原体包括一种环境纤维黏细菌菌株和一种没有已知近亲的新型ε变形菌菌株。疾病过程还在非常高的分类水平上导致了原核生物群落结构的重大变化。使用16S rRNA基因序列分析，仅在患病海绵中发现了属于ε变形菌和厚壁菌门的序列，并且患病海绵中的拟杆菌序列数量要多得多。相比之下，只有健康海绵含有与蓝细菌和“OP1”候选门类相对应的序列，并且健康海绵以绿弯菌门和γ变形菌序列为主。总体而言，患病海绵中的细菌多样性明显高于健康海绵。这些结果为未来基于培养的实验提供了一个平台，以便从食气管鳃海绵中分离出假定的病原体并进行再感染试验来确定疾病病因。
