Bacterial Community Mapping of the Mouse Gastrointestinal Tract

Shenghua Gu,Xiaoman Lv,Xiao-Lei Wu,Jin-Na Zhang,Dandan Chen,Kun Wang,Li-Ping Duan,Yong Nie,Colin Dale

doi:10.1371/journal.pone.0074957

Abstract

Keeping mammalian gastrointestinal (GI) tract communities in balance is crucial for host health maintenance. However, our understanding of microbial communities in the GI tract is still very limited. In this study, samples taken from the GI tracts of C57BL/6 mice were subjected to 16S rRNA gene sequence-based analysis to examine the characteristic bacterial communities along the mouse GI tract, including those present in the stomach, duodenum, jejunum, ileum, cecum, colon and feces. Further analyses of the 283,234 valid sequences obtained from pyrosequencing revealed that the gastric, duodenal, large intestinal and fecal samples had higher phylogenetic diversity than the jejunum and ileum samples did. The microbial communities found in the small intestine and stomach were different from those seen in the large intestine and fecal samples. A greater proportion of Lactobacillaceae were found in the stomach and small intestine, while a larger proportion of anaerobes such as Bacteroidaceae, Prevotellaceae, Rikenellaceae, Lachnospiraceae, and Ruminococcaceae were found in the large intestine and feces. In addition, inter-mouse variations of microbiota were observed between the large intestinal and fecal samples, which were much smaller than those between the gastric and small intestinal samples. As far as we can ascertain, ours is the first study to systematically characterize bacterial communities from the GI tracts of C57BL/6 mice.

Highlights

The adult mammalian gastrointestinal (GI) tract is home to microorganisms with the number around 10 times greater than the total number of mammalian somatic and germ cells [1]
Recent studies on GI microbiota confirmed that a balance in GI microbial communities is crucial for host health maintenance; perturbation of this microbial composition has been hypothesized to be involved in a range of diseases outside the gut, such as diabetes [3], obesity [4], fatty liver[5], inflammatory bowel diseases [6], anxiety [7] and even cancer [8]
Increasing research has been performed on mammalian gastrointestinal tract microbial ecology, most of the samples used in these studies were from the feces

Summary

Introduction

The adult mammalian gastrointestinal (GI) tract is home to microorganisms with the number around 10 times greater than the total number of mammalian somatic and germ cells [1]. Recent studies on GI microbiota confirmed that a balance in GI microbial communities is crucial for host health maintenance; perturbation of this microbial composition has been hypothesized to be involved in a range of diseases outside the gut, such as diabetes [3], obesity [4], fatty liver[5], inflammatory bowel diseases [6], anxiety [7] and even cancer [8]. Our understanding of the characteristic microbiota in different sections along with the GI tract is still very limited, especially for C57BL/6 mice, which are one of the most commonly used animals for studying gut microbiota related diseases [9]. Because the comprehensive characterization of normal mouse GI tract microbial communities is a critical prerequisite to understanding and predicting alterations in these communities in relation to disease, we conducted a study to characterize the GI tract microbiota of specific pathogen free (SPF) C57BL/6 mice using a recently developed high-throughput pyrosequencing approach

Methods

Results

Conclusion