title: Comparative Genomics Revealed Genetic Diversity and Species/Strain-Level Differences in Carbohydrate Metabolism of Three Probiotic Bifidobacterial Species.
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.
authors.affiliation: Food Science and Technology Institute, Morinaga Milk Industry Co., Ltd., No. 1-83, 5-Chome Higashihara, Zama, Kanagawa, Japan.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Odamaki
authors.affiliation: Food Science and Technology Institute, Morinaga Milk Industry Co., Ltd., No. 1-83, 5-Chome Higashihara, Zama, Kanagawa, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Horigome
authors.affiliation: Food Science and Technology Institute, Morinaga Milk Industry Co., Ltd., No. 1-83, 5-Chome Higashihara, Zama, Kanagawa, Japan.
authors.forename: Hirosuke
authors.initials: H
authors.lastname: Sugahara
authors.affiliation: Food Science and Technology Institute, Morinaga Milk Industry Co., Ltd., No. 1-83, 5-Chome Higashihara, Zama, Kanagawa, Japan.
authors.forename: Nanami
authors.initials: N
authors.lastname: Hashikura
authors.affiliation: Food Science and Technology Institute, Morinaga Milk Industry Co., Ltd., No. 1-83, 5-Chome Higashihara, Zama, Kanagawa, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Minami
authors.affiliation: Food Science and Technology Institute, Morinaga Milk Industry Co., Ltd., No. 1-83, 5-Chome Higashihara, Zama, Kanagawa, Japan.
authors.forename: Jin-Zhong
authors.initials: JZ
authors.lastname: Xiao
authors.affiliation: Food Science and Technology Institute, Morinaga Milk Industry Co., Ltd., No. 1-83, 5-Chome Higashihara, Zama, Kanagawa, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Abe