Natto is a traditional Japanese fermented soy product high in γ-polyglutamic acid (γ-PGA), whose beneficial effects have been reported. We prepared high-γ-PGA natto and compared the dietary influence on liver lipids and cecal microbiota in mice fed a diet containing it or a standard diet. The mice were served a 30% high-γ-PGA natto diet (PGA group) or standard diet (Con group) for 28 days. Liver lipids, fecal lipids, and fecal bile acids were quantified. Cecal microbiota were analyzed by PCR amplification of the V3 and V4 regions of 16S rRNA genes and sequenced using a MiSeq System. Additionally, the cecal short-chain fatty acid profile was assessed. The results revealed that the liver lipid and triglyceride contents were significantly lower (p<0.01) and amounts of bile acids and lipids in the feces were significantly higher in the PGA group than in the Con group. The cecal butyric acid concentration was observed to be significantly higher in the PGA group than in the Con group. Principal component analysis of the cecal microbiota revealed that the PGA and Con groups were distinct. The ratio of Firmicutes/Bacteroidetes was found to be significantly low in the PGA mice. The results revealed a significantly higher relative abundance of Lachnospiraceae (p<0.05) and significantly lower relative abundance of Coriobacteriaceae (p<0.01) in the PGA group. Analysis of the correlation between bacterial abundance and liver lipids, cecal short-chain fatty acids, fecal lipids, and fecal bile acids suggested that intestinal microbiota can be categorized into different types based on lipid metabolism. Hepatic lipid accumulation typically facilitates the onset of nonalcoholic fatty liver disease (NAFLD). Our findings high-γ-PGA natto is a beneficial dietary component for the prevention of NAFLD.
The fecal microbiota and short-chain fatty acids (SCFAs) play important roles in the human body. This study examined how hyperbaric conditions affect the fecal microbiota and fecal SCFAs. Fecal samples were obtained from 12 divers at three points during deep-diving training (before the diving training, at 2.1 MPa, and after decompression). At 2.1 MPa, the changes in the frequency of Clostridium cluster IV and fecal iso-valerate levels were positively correlated, and the changes in the frequencies of Bacteroides and Clostridium subcluster XIVa were inversely correlated. After decompression, positive correlations were detected between the changes in the frequency of Bifidobacterium and fecal n-valerate levels and between the changes in the fecal levels of iso-butyrate and iso-valerate. On the other hand, inverse correlations were detected between the changes in the frequency of Clostridium cluster IX and fecal iso-butyrate levels, between the changes in the frequency of Clostridium cluster IX and fecal iso-valerate levels, and between the changes in the frequencies of Bacteroides and Clostridium cluster IV plus subcluster XIVa. During the study period, the changes in fecal iso-butyrate and iso-valerate levels were positively correlated, and inverse correlations were seen between the changes in the frequency of Clostridium cluster IV and fecal propionate levels and between the changes in the frequencies of Prevotella and Clostridium subcluster XIVa. These findings suggest that hyperbaric conditions affect the fecal microbiota and fecal SCFA levels and that intestinal conditions reversibly deteriorate under hyperbaric conditions.
This study aimed to reveal the differences in intestinal microbes in osteoporotic rats. The rats were divided into two groups: the control and OP (osteoporosis) groups (n=6). Days 0 and 70 were set as the time points. The rats in the OP group underwent bilateral ovariectomy (OVX). Differences between the control and OP groups were determined by 16S rDNA analysis. The relative abundances of OTUs and alpha/beta diversities were determined at days 0 days and 70. The abundances of Verrucomicrobia at the phylum level and Aerococcus, Coprobacillus, Veillonella, Anaerobiospirillum, Flavobacterium, Comamonadaceae, Ohtaekwangia, etc., at the genus level were found to be different between the control_70d and OP_70d groups. KEGG ontology analysis showed that the function of lipid metabolism could be related to OP. The 16S rDNA analysis in the OP rats revealed that intestinal microbes take part in the processes of OP and could affect lipid metabolism. Further study of the relationship between OP and intestinal microbes is necessary, and the prospect for intestinal microbes is a potential treatment for OP.
Sarcopenia causes functional disorders and decreases the quality of life. Thus, it has attracted substantial attention in the aging modern world. Dysbiosis of the intestinal microbiota is associated with sarcopenia; however, it remains unclear whether prebiotics change the microbiota composition and result in the subsequent recovery of muscle atrophy in elderly patients with sarcopenia. This study aimed to assess the effects of prebiotics in super-elderly patients with sarcopenia. We analyzed the effects of 1-kestose on the changes in the intestinal microbiota and body composition using a next-generation sequencer and a multi-frequency bioimpedance analysis device. The Bifidobacterium longum population was significantly increased in the intestine after 1-kestose administration. In addition, in all six patients after 12 weeks of 1-kestose administration, the skeletal muscle mass index was greater, and the body fat percentage was lower. This is the first study to show that administration of a prebiotic increased the population of Bifidobacterium longum in the intestinal microbiota and caused recovery of muscle atrophy in super-elderly patients with sarcopenia.
Due to the high prevalence of vascular obstructive diseases, discovering potent, safe, and affordable fibrinolytic agents is of importance. There is particular interest concerning the use of functional foods that have a fibrinolytic activity, such as natto, a Japanese fermented soy-based product made with Bacillus subtilis (natto) strain BEST195. We recently isolated another bacterial strain from natto commercialized in Indonesia, Bacillus subtilis G8 , which has proven to exert fibrinolytic activity. Herein, a further characterization of Bacillus subtilis G8 was assessed through a comparison with commercialized nattokinase, the major fibrinolytic enzyme of Bacillus subtilis, by utilizing various in vitro fibrinolytic assays, namely whole blood clot lysis, euglobulin clot lysis, the fibrin plate method, and zymography. Both nattokinase and Bacillus subtilis G8 were able to dissolve both whole blood and euglobulin clots. Furthermore, both nattokinase and Bacillus subtilis G8 were able to lyse blood clots, presumably due to their ability to directly lyse fibrin. Finally, a crude extract of Bacillus subtilis G8 displayed six zymogram bands of approximately 42.0, 35.5, 30.8, 26.7, 20.0, and 13.7 kDa, with the strongest activity observed at 20.0 kDa. This indicates that Bacillus subtilis G8 contained several fibrinolytic enzymes, which might have comprised nattokinase and other fibrinolytic enzymes. In summary, we demonstrated that a crude extract of Bacillus subtilis G8 has potent fibrinolytic activity and that the activity was mediated by various fibrinolytic enzymes.
Construction of a diverting stoma can significantly reduce the onset of severe anastomotic leakage in patients with rectal cancer. High-output stoma is one of the most important potential surgical complications after anal function-preserving surgery with ileostomy. Culture-independent techniques have revealed the interaction of the complex intestinal bacterial ecology with various diseases. Our objective was to evaluate the differences in patient characteristics and gut microbiota distribution features in patients with high-output stomas. The cases of 24 consecutive patients who underwent curative resection for rectal cancer at our hospital between November 2016 and June 2018 were reviewed, and the patients were categorized into high-output and low-output groups. Their microbiota were analyzed using next-generation sequencing of ileostomy stool samples collected on postoperative day 7. There was a significant difference in the percentage of Bacteroidetes between the high-output and low-output groups (14.8% vs. 0.5%; p=0.01). The percentage of Clostridium butyricum was increased in the low-output group (p=0.01). After the exclusion of those treated with the probiotic Miya-BM, whose principal component is C. butyricum, analyses revealed no significant differences between the high-output and low-output groups. This pilot study provides the first evidence correlating gut microbiota with the pathogenesis of high- output stoma compared with low-output stoma.