Dataset Information

Nitrogenase diversity and activity in the gastrointestinal tract of the wood-eating catfish Panaque nigrolineatus.

ABSTRACT: The Amazonian catfish, Panaque nigrolineatus, consume large amounts of wood in their diets. The nitrogen-fixing community within the gastrointestinal (GI) tract of these catfish was found to include nifH phylotypes that are closely related to Clostridium sp., Alpha and Gammaproteobacteria, and sequences associated with GI tracts of lower termites. Fish fed a diet of sterilized palm wood were found to contain nifH messenger RNA within their GI tracts, displaying high sequence similarity to the nitrogen-fixing Bradyrhizobium group. Nitrogenase activity, measured by acetylene reduction assays, could be detected in freshly dissected GI tract material and also from anaerobic enrichment cultures propagated in nitrogen-free enrichment media; nifH sequences retrieved from these cultures were dominated by Klebsiella- and Clostridium-like sequences. Microscopic examination using catalyzed reporter deposition-enhanced immunofluorescence revealed high densities of nitrogenase-containing cells colonizing the woody digesta within the GI tract, as well as cells residing within the intestinal mucous layer. Our findings suggest that the P. nigrolineatus GI tract provides a suitable environment for nitrogen fixation that may facilitate production of reduced nitrogen by the resident microbial population under nitrogen limiting conditions. Whether this community is providing reduced nitrogen to the host in an active or passive manner and whether it is present in a permanent or transient relationship remains to be determined. The intake of a cellulose rich diet and the presence of a suitable environment for nitrogen fixation suggest that the GI tract microbial community may allow a unique trophic niche for P. nigrolineatus among fish.

SUBMITTER: McDonald R

PROVIDER: S-EPMC4817639 | biostudies-literature | 2015 Dec

REPOSITORIES: biostudies-literature

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Nitrogenase diversity and activity in the gastrointestinal tract of the wood-eating catfish Panaque nigrolineatus.

McDonald Ryan R Zhang Fan F Watts Joy E M JE Schreier Harold J HJ

The ISME journal 20150424 12

The Amazonian catfish, Panaque nigrolineatus, consume large amounts of wood in their diets. The nitrogen-fixing community within the gastrointestinal (GI) tract of these catfish was found to include nifH phylotypes that are closely related to Clostridium sp., Alpha and Gammaproteobacteria, and sequences associated with GI tracts of lower termites. Fish fed a diet of sterilized palm wood were found to contain nifH messenger RNA within their GI tracts, displaying high sequence similarity to the ni ...[more]

PMID: 25909976

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Project description:The Neotropical detritivorous catfish Panaque nigrolineatus imbibes large quantities of wood as part of its diet. Due to the interest in cellulose, hemi-cellulose and lignin degradation pathways, this organism provides an interesting model system for the detection of novel microbial catabolism. In this study, we characterize the microbial community present in different regions of the alimentary tract of P. nigrolineatus fed a mixed diet of date palm and palm wood in laboratory aquaria. Analysis was performed on 16S rRNA gene clone libraries derived from anterior and posterior regions of the alimentary tract and the auxiliary lobe (AL), an uncharacterized organ that is vascularly attached to the midgut. Sequence analysis and phylogenetic reconstruction revealed distinct microbial communities in each tissue region. The foregut community shared many phylotypes in common with aquarium tank water and included Legionella and Hyphomicrobium spp. As the analysis moved further into the gastrointestinal tract, phylotypes with high levels of 16S rRNA sequence similarity to nitrogen-fixing Rhizobium and Agrobacterium spp. and Clostridium xylanovorans and Clostridium saccharolyticum, dominated midgut and AL communities. However, the hindgut was dominated almost exclusively by phylotypes with the highest 16S rRNA sequence similarity to the Cytophaga-Flavobacterium-Bacteroides phylum. Species richness was highest in the foregut (Chao(1) = 26.72), decreased distally through the midgut (Chao(1) = 25.38) and hindgut (Chao(1) = 20.60), with the lowest diversity detected in the AL (Chao(1) = 18.04), indicating the presence of a specialized microbial community. Using 16S rRNA gene phylogeny, we report that the P. nigrolineatus gastrointestinal tract possesses a microbial community closely related to microorganisms capable of cellulose degradation and nitrogen fixation. Further studies are underway to determine the role of this resident microbial community in Panaque nigrolineatus.

Project description:The chicken gastrointestinal tract (GIT) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. Other studies were already performed to define the chicken gut metagenome and its fecal metaproteome. For the first time, the present study analysed dietary effects on the protein inventory of the microbiota in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorus (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increasedraised with the amount of MP while proteins of Lactobacillaceae werewas more abundant in the MP-lacking diets. Classification of the identified proteins into COGs and KEGG pathways underlined a diverse microbiota activity depending on the dietary regimen, indicating a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Insights oninto the identified KEGG pathways, as well as comparison between the GIT sections, dietary treatments, and the bacterial families encoding for the pathways of interest are provided. T) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. Other studies were already performed to define the chicken gut metagenome and its fecal metaproteome. For the first time, the present study analysed dietary effects on the protein inventory of the microbiota in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorus (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increasedraised with the amount of MP while proteins of Lactobacillaceae werewas more abundant in the MP-lacking diets. Classification of the identified proteins into COGs and KEGG pathways underlined a diverse microbiota activity depending on the dietary regimen, indicating a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Insights oninto the identified KEGG pathways, as well as comparison between the GIT sections, dietary treatments, and the bacterial families encoding for the pathways of interest are provided.

Dataset Information

Nitrogenase diversity and activity in the gastrointestinal tract of the wood-eating catfish Panaque nigrolineatus.

Publications

Nitrogenase diversity and activity in the gastrointestinal tract of the wood-eating catfish Panaque nigrolineatus.

Similar Datasets

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