Time filter

Source Type

Zhang M.,Shanghai JiaoTong University | Zhang M.,Shanghai Jiao Da Onlly Company Ltd | Hang X.,Shanghai Jiao Da Onlly Company Ltd | Tan J.,Shanghai JiaoTong University | Yang H.,Shanghai JiaoTong University
Applied and Environmental Microbiology | Year: 2015

To investigate the influences of host genotype and environment on Bifidobacterium longum subsp. longum inhabiting human intestines at the strain level, six pairs of twins, divided into two groups (children and adults), were recruited. Each group consisted of two monozygotic (MZ) twin pairs and one dizygotic (DZ) twin pair. Child twins had been living together from birth, while adult twins had been living separately for 5 to 10 years. A total of 345 B. longum subsp. longum isolates obtained from 60 fecal samples from these twins were analyzed by multilocus sequence typing (MLST), and 35 sequence types (STs) were finally acquired. Comparison of strains within and between the twin pairs showed that no strains with identical STs were observed between unrelated individuals or within adult DZ twin pairs. Eight STs were found to be monophyletic, existing within MZ twins and child DZ twins. The similarity of strain types within child cotwins was significantly higher than that within adult cotwins, which indicated that environment was one of the important determinants in B. longum subsp. longum strain types inhabiting human intestines. However, although these differences between MZ and DZ twins were observed, it is still difficult to reach an exact conclusion about the impact of host genotype. This is mainly because of the limited number of subjects tested in the present study and the lack of strain types tracing in the same twin pairs from birth until adulthood. © 2015, American Society for Microbiology.


Yang X.,Shanghai JiaoTong University | Hang X.,Shanghai Jiao Da Onlly Company Ltd | Tan J.,Shanghai JiaoTong University | Yang H.,Shanghai JiaoTong University
Anaerobe | Year: 2015

Bifidobacteria are common inhabitants of the human gastrointestinal tract, and their application has increased dramatically in recent years due to their health-promoting effects. The ability of bifidobacteria to tolerate acidic environments is particularly important for their function as probiotics because they encounter such environments in food products and during passage through the gastrointestinal tract. In this study, we generated a derivative, Bifidobacterium breve BB8dpH, which displayed a stable, acid-resistant phenotype. To investigate the possible reasons for the higher acid tolerance of B.breve BB8dpH, as compared with its parental strain B.breve BB8, a combined transcriptome and physiological approach was used to characterize differences between the two strains. An analysis of the transcriptome by RNA-sequencing indicated that the expression of 121 genes was increased by more than 2-fold, while the expression of 146 genes was reduced more than 2-fold, in B.breve BB8dpH. Validation of the RNA-sequencing data using real-time quantitative PCR analysis demonstrated that the RNA-sequencing results were highly reliable. The comparison analysis, based on differentially expressed genes, suggested that the acid tolerance of B.breve BB8dpH was enhanced by regulating the expression of genes involved in carbohydrate transport and metabolism, energy production, synthesis of cell envelope components (peptidoglycan and exopolysaccharide), synthesis and transport of glutamate and glutamine, and histidine synthesis. Furthermore, an analysis of physiological data showed that B.breve BB8dpH displayed higher production of exopolysaccharide and lower H+-ATPase activity than B.breve BB8. The results presented here will improve our understanding of acid tolerance in bifidobacteria, and they will lead to the development of new strategies to enhance the acid tolerance of bifidobacterial strains. © 2015 Elsevier Ltd.


Yang X.,Shanghai JiaoTong University | Hang X.,Shanghai Jiao Da Onlly Company Ltd | Zhang M.,Shanghai JiaoTong University | Zhang M.,Shanghai Jiao Da Onlly Company Ltd | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2015

The acid tolerance is particularly important for bifidobacteria to function as probiotics because they usually encounter acidic environments in food products and gastrointestinal tract passage. In this study, two acid-resistant derivatives Bifidobacterium longum JDY1017dpH and Bifidobacterium breve BB8dpH, which displayed a stable acid-resistant phenotype, were generated. The relationship between acid tolerance and cell membrane was investigated by comparing the two acid-resistant derivatives and their parental strains grown in medium with and without Tween 80. The fold increase in acid tolerance of the two acid-resistant derivatives relative to their parental strains was much higher when cells were grown in medium with Tween 80 (104 ~ 105-fold) than without Tween 80 (181- and 245-fold). Moreover, when cells were grown in medium with Tween 80, the two acid-resistant derivatives exhibited more C18:1 and cycC19:0, higher mean fatty acid chain length, lower membrane fluidity, and higher expression of cfa gene encoding cyclopropane fatty acid synthase than their parental strains. No significant differences in cell membrane were observed between the two acid-resistant derivatives and their parental strains when cells were grown in medium without Tween 80. The present study revealed that, when cells were grown in medium with Tween 80, the significant fold increase in acid tolerance of the two acid-resistant derivatives was mainly ascribed to the pronounced changes in cell membrane compared with their parental strains. Results presented here could provide a basis for developing new strategies of cell membrane modification to enhance acid tolerance in bifidobacteria. © 2015, Springer-Verlag Berlin Heidelberg.


PubMed | Shanghai Jiao Da Onlly Company Ltd and Shanghai JiaoTong University
Type: | Journal: Anaerobe | Year: 2015

Bifidobacteria are common inhabitants of the human gastrointestinal tract, and their application has increased dramatically in recent years due to their health-promoting effects. The ability of bifidobacteria to tolerate acidic environments is particularly important for their function as probiotics because they encounter such environments in food products and during passage through the gastrointestinal tract. In this study, we generated a derivative, Bifidobacterium breve BB8dpH, which displayed a stable, acid-resistant phenotype. To investigate the possible reasons for the higher acid tolerance of B.breve BB8dpH, as compared with its parental strain B.breve BB8, a combined transcriptome and physiological approach was used to characterize differences between the two strains. An analysis of the transcriptome by RNA-sequencing indicated that the expression of 121 genes was increased by more than 2-fold, while the expression of 146 genes was reduced more than 2-fold, in B.breve BB8dpH. Validation of the RNA-sequencing data using real-time quantitative PCR analysis demonstrated that the RNA-sequencing results were highly reliable. The comparison analysis, based on differentially expressed genes, suggested that the acid tolerance of B.breve BB8dpH was enhanced by regulating the expression of genes involved in carbohydrate transport and metabolism, energy production, synthesis of cell envelope components (peptidoglycan and exopolysaccharide), synthesis and transport of glutamate and glutamine, and histidine synthesis. Furthermore, an analysis of physiological data showed that B.breve BB8dpH displayed higher production of exopolysaccharide and lower H(+)-ATPase activity than B.breve BB8. The results presented here will improve our understanding of acid tolerance in bifidobacteria, and they will lead to the development of new strategies to enhance the acid tolerance of bifidobacterial strains.

Loading Shanghai Jiao Da Onlly Company Ltd collaborators
Loading Shanghai Jiao Da Onlly Company Ltd collaborators