Open AccessBacterial Community Associated with the Intestinal Tract of Chinese Mitten Crab (Eriocheir sinensis) Farmed in Lake Tai, China
Author(s) -
Xiaobing Chen,
Panpan Di,
Hongming Wang,
Bailin Li,
Yingjie Pan,
Shuling Yan,
Yongjie Wang
Publication year - 2015
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0123990
Subject(s) - biology , bacteroidetes , hindgut , midgut , candidatus , proteobacteria , microbiology and biotechnology , temperature gradient gel electrophoresis , firmicutes , phylotype , eriocheir , 16s ribosomal rna , bacteria , zoology , botany , genetics , larva
Chinese mitten crab (CMC, Eriocheir sinensis ) is an economically valuable species in South-East Asia that has been widely farmed in China. Characterization of the intestinal bacterial diversity of CMC will provide insights into the aquaculturing of CMCs. Based on the analysis of cloned 16S rRNA genes from culture-independent CMC gut bacteria, 124 out of 128 different clones reveal 95% nucleotide similarity to the species belonging to the four phyla of Tenericutes , Bacteroidetes , Firmicutes and Proteobacteria ; one clone shows 91% sequence similarity to the member of TM7 (a candidate phylum without cultured representatives). Fluorescent in situ hybridization also reveals the abundance of Bacteroidetes in crab intestine. Electron micrographs show that spherical and filamentous bacteria are closely associated with the microvillus brush border of the midgut epithelium and are often inserted into the space between the microvilli using a stalk-like cell appendage. In contrast, the predominant rod-shaped bacteria in the hindgut are tightly attached to the epithelium surface by an unusual pili-like structure. Both 16S rRNA gene denaturing gel gradient electrophoresis and metagenome library indicate that the CMC Mollicutes group 2 appears to be present in both the midgut and hindgut with no significant difference in abundance. The CMC Mollicutes group 1, however, was found mostly in the midgut of CMCs. The CMC gut Mollicutes phylotypes appear to be most closely related to Mollicutes symbionts detected in the gut of isopods (Crustacea: Isopoda). Overall, the results suggest that CMCs harbor diverse, novel and specific gut bacteria, which are likely to live in close relationships with the CMC host.