Expression Analysis and the Roles of the Sec1 Gene in Regulating the Composition of Mouse Gut Microbiota

The Sec1 gene encodes galactose 2-L-fucosyltransferase, whereas expression during development of the Sec1 gene mouse and its effect on the composition of the gut microbiota have rarely been reported. In this study, we examined Sec1 gene expression during mouse development, constructed Sec1 knockout mice, and sequenced their gut microbial composition. It was found that Sec1 was expressed at different stages of mouse development. Sec1 knockout mice have significantly higher intraperitoneal fat accumulation and body weight than wild-type mice. Analysis of gut microbial composition in Sec1 knockout mice revealed that at the phylum level, Bacteroidetes accounted for 68.8%and 68.3% of gut microbial composition in the Sec1^-/- and Sec1^+/+ groups, respectively, and Firmicutes accounted for 27.1% and 19.7%, respectively; while Firmicutes/Bacteroidetes were significantly higher in Sec1^-/- mice than in Sec1^+/+ mice (39.4% vs. 28.8%). In verucomicrobia, it was significantly higher in Sec1^-/- mice than in Sec1^+/+ group mice. At the family level, the dominant bacteria Prevotellaceae, Akkermansiaceae, Bacteroidaceae, and Lacilltobacaceae were found to be significantly reduced in the gut of Sec1^-/- mice among Sec1^+/+ gut microbes, while Lachnospiraceae, Ruminococcaceae, Rikenellaceae, Helicobacteraceae, and Tannerellaceae were significantly increased. Indicator prediction also revealed the dominant bacteria Akkermansiaceae and Lactobacillaceae in Sec1^+/+ gut microorganisms, while the dominant bacteria Rikenellaceae, Marinifilaceae, ClostridialesvadinBB60aceae, Erysipelotrichaceae, Saccharimonadaceae, Clostridiaceae1, and Christensenellaceae in Sec1^-/- group. This study revealed that the Sec1 gene was expressed in different tissues at different time periods in mice, and Sec1 knockout mice had significant weight gain, significant abdominal fat accumulation, and significant changes in gut microbial flora abundance and metabolic function, providing a theoretical basis and data support for the study of Sec1 gene function and effects on gut microbiota-related diseases.

Musa basjoo regulates the gut microbiota in mice by rebalancing the abundance of probiotic and pathogen

Musa basjoo is a kind of popular slimming fruit in southern China. However, even though the trophic component and physiological effect are well studied, its internal mechanism in reconstructing gut microbiota remains unclear. In this study, maturity of M. basjoo were divided into four levels. Results indicated that M. basjoo in level Ⅱ (with 35% maturity) represented the greatest increase in the growth in vitro of probiotics, Lactobacillus plantarum FMNP01 and Lactobacillus casei FMNP02. After feeding M. basjoo with the middle dose (2.67 g/kg·BW) to mice for 21 days, gut microbiota from mice feces was isolated and sequenced. Results of 16SrDNA sequencing showed that the scattered genera of gut microbiota were significantly gathered. The amounts of different pathogens were decreased, while probiotics such as genera Bacteroides and Roseburia were significantly increased (p < 0.05). Results of function prediction indicated that the reconstruction of gut microbiota may due to the change in carbohydrate transportation, biosynthesis of cell wall, cell membrane, and cell envelope. This study has drawn a basic mechanism in reconstructing gut microbiota by feeding M. basjoo and lay out a foundation for further reach on the interaction between human as diner and M. basjoo as food.

Characterization of the cervical bacterial community in dairy cows with metritis and during different physiological phases

For the development of disease prevention and intervention strategies, a better understanding of the dynamics and interactions within cervical bacterial communities in both healthy cows and cows with metritis is required. Understanding the complexity and ecology of microorganisms in the vagina of dairy cows with metritis and during different physiological phases is critical for developing strategies to balance microorganism content. To gain deeper insight into fluctuations within the cervical microbiota, swab samples were collected from 40 Holstein dairy cows, and16S rDNA amplicon sequencing was used to analyze cervical bacterial diversity. Meanwhile, vaginal bacterial composition was analyzed during different physiological phases, including the formative (CF), gestational (CG), and postpartum (CP) stages, and in cows with metritis (CM). The results revealed a complex profile with extensive differences in the cervical bacterial composition. A total of 678,043clean 16S rDNA V4-V6 reads were gained, and 1877 Operational Taxonomic Units (OTUs) were observed after calculation. At both the phylum and genus levels, the top 10 bacteria by percentage were the same when comparing the CF, CG, and CP groups of cows, with some variation in abundance. At the phylum level, the cervical microbial community in the CF, CG, and CP groups included mainly Firmicutes, which accounted for 39.3%, 48.3%, and 49.6% of the total microbial composition of each group, respectively. However, the cervical bacterial community in the CM group consisted of mostly Bacteroidetes, which accounted for 72.6% of the total microbial composition. The second major bacterial community in the CF and CG groups of cows was Proteobacteria, which accounted for 28.3%and 30.1% of the total microbial compositions of these groups, respectively, while the second major bacterial community in the CP group was Bacteroidetes (23.5%). However, in the CM group, the second major bacterial community was Fusobacteria, which accounted for18.0% of the total microbial composition. At the genus level, the cervical bacterial community in the CM group of cows was dominated by Porphyromonas(44.4%) and Fusobacterium(12.1%), while Porphyromonas accounted for only 1.3%, 1.1%, and 1.4% of the total microbial compositions of the CF, CG, and CP groups, respectively. Likewise, Fusobacterium accounted for 2.3%, 0.7%, and 4.7% of the total microbial compositions of the CF, CG, and CP groups, respectively. The results demonstrate that cervical bacterial diversity decreases in cows with metritis and that the predominant bacterial genera are Porphyromonas and Fusobacterium. Cervical bacterial diversity was rich in all observed physiological phases, and the predominant bacterial phylum was Firmicutes. Pregnancy had little effect on the cervical bacterial community; however, there were increases in the abundances of pathogenic species in postpartum cows. Cervical bacterial diversity decreased in cows with metritis, however, due to the highly dynamic and complex course of metritis, the relationship between cervical bacterial diversity and metritis requires further investigation.