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Chen X, Di P, Wang H, Li B, Pan Y, Yan S, Wang Y. Bacterial community associated with the intestinal tract of Chinese mitten crab (Eriocheir sinensis) farmed in Lake Tai, China. PLoS One 2015; 10:e0123990. [PMID: 25875449 PMCID: PMC4395229 DOI: 10.1371/journal.pone.0123990] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/25/2015] [Indexed: 01/16/2023] Open
Abstract
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.
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Affiliation(s)
- Xiaobing Chen
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation, Ministry of Agriculture, Shanghai, China
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Panpan Di
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation, Ministry of Agriculture, Shanghai, China
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Hongming Wang
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation, Ministry of Agriculture, Shanghai, China
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Bailin Li
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Yingjie Pan
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation, Ministry of Agriculture, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Shuling Yan
- Institute of Biochemistry and Molecular Cell Biology, University of Goettingen, Goettingen, Germany
| | - Yongjie Wang
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation, Ministry of Agriculture, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
- * E-mail:
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Lu M, Wang X, Sun G, Qin B, Xiao J, Yan S, Pan Y, Wang Y. Fine structure of Tibetan kefir grains and their yeast distribution, diversity, and shift. PLoS One 2014; 9:e101387. [PMID: 24977409 PMCID: PMC4076316 DOI: 10.1371/journal.pone.0101387] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 06/06/2014] [Indexed: 02/03/2023] Open
Abstract
Tibetan kefir grains (TKGs), a kind of natural starter for fermented milk in Tibet, China, host various microorganisms of lactic acid bacteria, yeasts, and occasionally acetic acid bacteria in a polysaccharide/protein matrix. In the present study, the fine structure of TKGs was studied to shed light on this unusual symbiosis with stereomicroscopy and thin sections. The results reveal that TKGs consist of numerous small grain units, which are characterized by a hollow globular structure with a diameter between 2.0 and 9.0 mm and a wall thickness of approximately 200 µm. A polyhedron-like net structure, formed mainly by the bacteria, was observed in the wall of the grain units, which has not been reported previously to our knowledge. Towards the inside of the grain unit, the polyhedron-like net structures became gradually larger in diameter and fewer in number. Such fine structures may play a crucial role in the stability of the grains. Subsequently, the distribution, diversity, and shift of yeasts in TKGs were investigated based on thin section, scanning electron microscopy, cloning and sequencing of D1/D2 of the 26S rRNA gene, real-time quantitative PCR, and in situ hybridization with specific fluorescence-labeled oligonucleotide probes. These show that (i) yeasts appear to localize on the outer surface of the grains and grow normally together to form colonies embedded in the bacterial community; (ii) the diversity of yeasts is relatively low on genus level with three dominant species – Saccharomyces cerevisiae, Kluyveromyces marxianus, and Yarrowia lipolytica; (iii) S. cerevisiae is the stable predominant yeast species, while the composition of Kluyveromyces and Yarrowia are subject to change over time. Our results indicate that TKGs are relatively stable in structure, and culture conditions to some extent shape the microbial community and interaction in kefir grains. These findings pave the way for further study of the specific symbiotic associations between S. cerevisiae and Lactobacillus bacteria in TKGs.
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Affiliation(s)
- Man Lu
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation (Shanghai), Ministry of Agriculture, Shanghai, China; College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Xingxing Wang
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation (Shanghai), Ministry of Agriculture, Shanghai, China; College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Guowei Sun
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation (Shanghai), Ministry of Agriculture, Shanghai, China; College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Bing Qin
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation (Shanghai), Ministry of Agriculture, Shanghai, China; College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Jinzhou Xiao
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation (Shanghai), Ministry of Agriculture, Shanghai, China; College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Shuling Yan
- Institute of Biochemistry and Molecular Cell Biology, University of Goettingen, Goettingen, Germany
| | - Yingjie Pan
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation (Shanghai), Ministry of Agriculture, Shanghai, China; College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Yongjie Wang
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage & Preservation (Shanghai), Ministry of Agriculture, Shanghai, China; College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
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