Distribution and Stress Resistance of Resident Lactobacilli in Mouse Intestinal Tract

Abstract

In this paper, we studied the spatial distribution and stress responses of resident Lactobacillus in various intestinal regions in order to clarify the ecological and functional properties of the microbes in mouse normal microflora. Lactobacillus reuteri and Lactobacillus intestinalis were identified as resident species by 16S rDNA analysis. Both lactobacilli were present in all regions of the intestinal tract (duodenum, jejunum+ileum, cecum and colon) at almost the same ratios based on colony shapes on LBS agar and the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiles using a genus-specific primer pair. Survivability of L. reuteri against heat shock, acid and bile salt treatments was markedly higher than that of L. intestinalis. Furthermore, almost all isolates of L. reuteri obtained from all intestinal regions grew in MRS broth with 0.5% bile salts, while almost all of the isolates of L. intestinalis failed to grow in the broth with 0.1% bile salts. These results suggest that resident lactobacilli, L. reuteri and L. intestinalis, in mice are able to colonize all intestinal regions with different environmental conditions, regardless of their stress response potentials.

Induction of gut Lactobacillus reuteri in normal ICR mice by oral administration of L. plantarum AN1

“…L. intestinalis , which was the predominant LAB in this study, is regarded as a normal resident bacterium in mice and rat intestines (Fujisawa, Itoh, Benno, & Mitsuoka, ; Park & Itoh, ). L. intestinalis and L. reuteri can colonize all intestinal regions, including the duodenum, jejunum, and ileum (Hata et al, ). There are many reports on the probiotic properties of L. gasseri , which is reported to have anti‐inflammatory, immune‐promoting, and anti‐obesity activities (Kawano, Miyoshi, Ogawa, Sakai, & Kadooka, ; Kawase et al, ; Ukibe, Miyoshi, & Kadooka, ).…”

“…Bifidobacterium is a genus of beneficial predominantly gram‐positive anaerobic bacteria that reside in the human gut (Won, Sugahara, Odamaki, & Xiao, ). However, in the guts of the mice that are used for experiments on nutrition, functional foods, and lifestyle‐related diseases, Lactobacillus is the predominant bacterial genus (Hata et al, ). In the caecal microbiota of ICR (closed colony) mice fed a high‐fat diet or a high‐sucrose/no‐dietary fibre diet, a low abundance of Lactobacillus reuteri was correlated with chronic disease indices, such as large fat mass, high blood lipid levels, and/or shortened colon tissue (Kuda et al, ).…”