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International Journal of Genomics
Volume 2015, Article ID 567809, 12 pages
http://dx.doi.org/10.1155/2015/567809
Research Article

Comparative Genomics Revealed Genetic Diversity and Species/Strain-Level Differences in Carbohydrate Metabolism of Three Probiotic Bifidobacterial Species

Food Science and Technology Institute, Morinaga Milk Industry Co., Ltd., No. 1-83, 5-Chome Higashihara, Zama, Kanagawa, Japan

Received 30 December 2014; Revised 4 May 2015; Accepted 26 May 2015

Academic Editor: John Parkinson

Copyright © 2015 Toshitaka Odamaki et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Strains of Bifidobacterium longum, Bifidobacterium breve, and Bifidobacterium animalis are widely used as probiotics in the food industry. Although numerous studies have revealed the properties and functionality of these strains, it is uncertain whether these characteristics are species common or strain specific. To address this issue, we performed a comparative genomic analysis of 49 strains belonging to these three bifidobacterial species to describe their genetic diversity and to evaluate species-level differences. There were 166 common clusters between strains of B. breve and B. longum, whereas there were nine common clusters between strains of B. animalis and B. longum and four common clusters between strains of B. animalis and B. breve. Further analysis focused on carbohydrate metabolism revealed the existence of certain strain-dependent genes, such as those encoding enzymes for host glycan utilisation or certain membrane transporters, and many genes commonly distributed at the species level, as was previously reported in studies with limited strains. As B. longum and B. breve are human-residential bifidobacteria (HRB), whereas B. animalis is a non-HRB species, several of the differences in these species’ gene distributions might be the result of their adaptations to the nutrient environment. This information may aid both in selecting probiotic candidates and in understanding their potential function as probiotics.