Search

Background To investigate the causality between metformin and gut microbiome in the treatment of type 2 diabetes (T2D). Methods This study was conducted on individuals with newly diagnosed and treatment-naive T2D. We used 16s rRNA sequencing to understand the effect of metformin on the composition and diversity of the gut microbiota. We also compared the differences in relative abundances of gut microbiome at the genus level in treatment-naive T2D patients before and after metformin treatment for 2 months and used Spearman rank correlation coefficient analysis of genus abundance in relation to blood glucose and related factors. Results Metformin significantly reduced blood glucose and levels of the related factors in treatment-naive individuals with T2D after 2 months of treatment. 16s rRNA sequencing showed that metformin treatment altered the composition and diversity of the gut microbiome. Differences in relative abundances at the genus level among groups revealed that Megamonas and Klebsiella in T2D groups were significantly higher compared with those in the control group. Treatment with metformin caused a significant reduction in the abundances of Megamonas and Klebsiella. Spearman rank correlation coefficient analysis showed a significant positive correlation between Megamonas and blood glucose, HbA1c, GSP, and ALT. In Klebsiella, a significant positive correlation between HbA1c and ALT was found. Conclusions Metformin reduces blood glucose in T2D by interaction with different gut bacteria, possibly Megamonas and Klebsiella pneumoniae.

The pros and cons of monosodium glutamate (MSG), a common food additive, have been long disputed, whereas the effects of MSG consumption on human intestinal microbiome have not been fully understood. In the present study, metagenomics sequencing was performed to evaluate the effects of MSG on human intestinal microbiota (n = 12) during a four-week experiment. It was observed that MSG consumption did not significantly alter the intestinal microbial community structure and functional features of the subjects. Although some bacteria including Faecalibacterium, Megamonas, Blautia and Collinsella tended to change, there was no significant difference in the alteration of all genera. At the functional level, the microbial functions were rich, mainly distributed in membrane transport, amino acid metabolism and carbohydrate metabolism, but there was no significant difference between samples obtained at different times. Additionally, it was discovered that the impact of the individuals on intestinal microbiota was greater than that of MSG.

Accompanying human beings since the Paleolithic period, dogs has been recently regarded as a reliable model for the study of the gut microbiome connections with health and disease. In order to provide some glimpses on the connections between the gut microbiome layout and host behavior, we profiled the phylogenetic composition and structure of the canine gut microbiome of dogs with aggressive (n = 11), phobic (n = 13) and normal behavior (n = 18). Hormones’ determination was made through Radio Immuno-Assay (RIA), and next generation sequencing of the V3–V4 gene region of the bacterial 16S rRNA was employed to determine gut microbiome composition. Our results did not evidence any significant differences of hormonal levels between the three groups. According to our findings, aggressive behavioral disorder was found to be characterized by a peculiar gut microbiome structure, with high biodiversity and enrichment in generally subdominant bacterial genera (i.e. Catenibacterium and Megamonas). On the other hand, phobic dogs were enriched in Lactobacillus, a bacterial genus with known probiotic and psychobiotic properties. Although further studies are needed to validate our findings, our work supports the intriguing opportunity that different behavioral phenotypes in dogs may be associated with peculiar gut microbiome layouts, suggesting possible connections between the gut microbiome and the central nervous system and indicating the possible adoption of probiotic interventions aimed at restoring a balanced host-symbiont interplay for mitigating behavioral disorders., Biological sciences; Microbiology; Endocrinology; Veterinary medicine; Animal behavior; Microbiome, Behavioral disorders, Aggressive dogs, Phobic dogs, Hormones

Summary Bacteroides hypermegas ( Harrison and Hansen ) differs to such an extent from the type species of Bacteroides, Bacteroides fragilis ( Veillon and Zuber ), that it cannot be retained in this genus. On the basis of morphological, biochemical and chemical criteria it is suggested that Bacteroides hypermegas be reclassified in a new genus, Megamonas , as Megamonas hypermegas ( Harrison and Hansen ) comb. nov.