Mixture of Two Lactobacillus plantarum Strains Modulates the Gut Microbiota Structure and Regulatory T Cell Response in Diet-Induced Obese Mice.

SCOPE: The gut microbiota has been linked to diet-induced obesity, and microorganisms that influence obesity have important health implications. In this study, the anti-obesity effects of two Lactobacillus plantarum strains (DSR M2 and DSR 920) isolated from kimchi are investigated. METHODS AND RESULTS: Mice are fed a normal or high-fat diet with or without DSR M2 and DSR 920 (DSR, 1 × 109 CFU d-1 ) for 12 weeks. DSR improves the obesity state, as evidenced by the i) suppressed obesity-related markers, e.g., gains in body weight and fat mass, ii) reduced serum and liver triglyceride levels, iii) upregulated ß-oxidation and downregulated lipogenesis-related genes in the liver, iv) reduced serum leptin levels, v) altered microbial communities, vi) increased regulatory T cell immunity, and vii) suppressed inflammatory response. In addition, correlation analysis shows that Akkermansia muciniphila and the genus Anaerostipes, which are increased in the DSR group, are negatively correlated with obesity-related markers, but Mucispirillum schaedleri, which is increased in the high-fat-diet (HFD) group, is positively correlated with serum leptin level. CONCLUSION: Lactobacillus plantarum DSR M2 and DSR 920 are candidate probiotics for the prevention and amelioration of obesity.

Effects of Lactobacillus plantarum and Leuconostoc mesenteroides Probiotics on Human Seasonal and Avian Influenza Viruses.

Influenza viruses that cause recurrent seasonal epidemics to humans can be controlled with vaccine and antiviral therapy. However, the medical treatments often exhibit limited efficacy in the elderly or immunosuppressed individuals. In these cases, daily uptake of probiotic microbes may be an option to bring in health benefits against influenza. Here, we demonstrate the effects of probiotics Lactobacillus plantarum (Lp) and Leuconostoc mesenteroides (Lm) against seasonal and avian influenza viruses. As assessed by the plaque size reduction of human H1N1 and avian influenza H7N9 viruses, including green fluorescent protein-tagged H1N1 strain in cells, the selected Lp and Lm strains restrained viral replication in mouse lungs with statistical significance. Against lethal viral challenge, the Lp and Lm strains exhibited their beneficial effects by increasing the mean days and rates of survival of infected mice. These results suggest that, despite rather narrow ranges of protective efficacy, the dietary supplement of Lactobacillus and Leuconostoc probiotics may promote health benefits against influenza.

Development of Bile Salt-Resistant Leuconostoc citreum by Expression of Bile Salt Hydrolase Gene.

Probiotic bacteria must have not only tolerance against bile salt but also no genes for antibiotic resistance. Leuconostoc citreum is a dominant lactic acid bacterium in various fermented foods, but it is not regarded as a probiotic because it lacks bile salt resistance. Therefore, we aimed to construct a bile salt-resistant L. citreum strain by transforming it with a bile salt hydrolase gene (bsh). We obtained the 1,001 bp bsh gene from the chromosomal DNA of Lactobacillus plantarum and subcloned it into the pCB4170 vector under a constitutive P710 promoter. The resulting vector, pCB4170BSH was transformed into L. citreum CB2567 by electroporation, and bile saltresistant transformants were selected. Upon incubation with glycodeoxycholic acid sodium salt (GDCA), the L. citreum transformants grew and formed colonies, successfully transcribed the bsh gene, and expressed the BSH enzyme. The recombinant strain grew in up to 0.3% (w/v) GDCA, conditions unsuitable for the host strain. In in vitro digestion conditions of 10 mM bile salt, the transformant was over 67.6% viable, whereas only 0.8% of the host strain survived.

In vitro digestion and fermentation properties of linear sugar-beet arabinan and its oligosaccharides.

This study was conducted to investigate the prebiotic effects of linear arabino-oligosaccharides (LAOS) and debranched (linear) sugar beet arabinan (LAR) for the development of new prebiotics. LAOS were prepared from LAR by enzymatic hydrolysis with endo-arabinanase from Bacillus licheniformis, followed by removal of the arabinose fraction by incubation with resting cells of Leuconostoc mesenteroides. The resulting LAOS contained DP2 (28.7%), DP3 (49.9%), DP4 (20.1%), and DP5 (1.16%). A standardized digestibility test showed that LAOS and LAR were not digestible. Individual cultures of 24 strains of gastrointestinal bacteria showed that LAOS and LAR stimulated growth of Lactobacillus brevis, Bifidobacterium longum, and Bacteroides fragilis. In vitro batch fermentation using human fecal samples showed that LAOS had higher bifidogenic properties than LAR; LAOS increased the population of bifidobacteria which produced short-chain fatty acids (SCFAs). LAOS was fermented slowly compared to fructo-oligosaccharides and this may permit SCFA production in the distal colon. This study demonstrates that LAOS prepared from LAR are promising dietary substrates for improvement of human intestinal health.