Identification of commensal bacteria coated with secretory immunoglobulin A

　A part of commensal intestinal bacteria in mammal including human, mouse, bovine and pig are coated with secretory immunoglobulin A (S‒IgA). It has been suggested from our previous research that S‒IgA coating of commensal bacteria occur in bacterial group specific manner in human and mouse intestine. Thus, identification of S‒IgA‒coated bacterial genera/species would certainly help to elucidate the interaction between S‒IgA and commensal intestinal bacteria. However, the method to identify the genera/species of S‒IgA‒coated bacteria has not been established. To identify S‒IgA‒coated bacterial composition, we developed the method combining immunohistochemical detection of S‒IgA and subsequent 16S rRNA targeted fluorescence in situ hybridization (FISH) analysis. Furthermore, human and mice fecal S‒IgA coated bacterial composition was evaluated by this newly developed method with ten frequently‒used FISH probes. Fecal S‒IgA‒coated bacterial composition was successfully analyzed with this method and this analysis suggested that Enterobacteriaceae was preferably coated with S‒IgA whereas Bacteroides/Prevotella and Lactobacillus/ Enterococcus groups seemed to be poorly coated with S‒IgA. This method will be applied to confirm whether interaction between S‒IgA and commensal intestinal bacteria relate to symptom of inflammatory bowel diseases

Effect of Prompt-Delayed Packaging and Ensiling Time on Fermentation and Aerobic Stability of Soybean Curd Residue

Wet soybean curd residue (SCR) obtained from two tofu factories (F1 and F2) was anaerobically stored with or without added beet pulp (BP). Sealing was performed on the day of tofu production (prompt sealing [PS]) or 2 days after SCR was piled and unprocessed (delayed sealing [DS]). Predominant lactic acid fermentation was observed regardless of the sealing time and BP addition. Acinetobacter spp. were the most abundant (\u3e 67%) bacteria in pre-ensiled SCR, regardless of the factory and sealing time. In PS silage, the abundances of typical lactic acid-producing bacteria, such as Lactobacillus, Pediococcus, and Streptococcus spp. reached \u3e 50%. In DS silage, Acinetobacter spp. were the most abundant in F1 products, whereas Bacillus spp. were the most abundant in long-stored F2 products. These results indicated that owing to preceding processing, including heating, distinctive microbiota may have participated in the ensiling of wet by-products. Lactic acid fermentation was observed even in DS silage, and an association of Bacillus spp. was suggested

Modulatory Effects of A1 Milk, A2 Milk, Soy, and Egg Proteins on Gut Microbiota and Fermentation

Milk can be divided into A1 and A2 types according to fi-casein variants, and there is a debate about whether A1 milk consumption exacerbates gut environments. This study examined the cecum microbiota and fermentation in mice fed A1 casein, A2 casein, mixed casein (commercial casein), soy protein isolate, and egg white. The cecum acetic acid concentration was higher, and the relative abundances of Muribaculaceae and Desulfovibrionaceae were greater in mice fed A1 versus A2 casein. The other parameters of cecum fermentation and microbiota composition were similar among the mice fed A1, A2, and mixed caseins. The differences were more distinctive among the three caseins, soy, and egg feedings. Chao 1 and Shannon indices of the cecum microbiota were lowered in egg white-fed mice, and the microbiota of mice fed milk, soy, and egg proteins were separately grouped by principal coordinate analysis. Mice fed the three caseins were characterized by a high abundance of Lactobacillaceae and Clostridiaceae, those fed soy were characterized by Corynebacteriaceae, Muribaculaceae, and Ruminococcaceae, and those fed egg white were characterized by Eggerthellaceae, Rikenellaceae, and Erysipelatoclostridiaceae. Thus, although several differences can arise between A1 and A2 caseins in terms of their modulatory effects on gut environments, the differences between milk, soy, and egg proteins can be more distinctive and are worth further consideration

Cecum microbiota in rats fed soy, milk, meat, fish, and egg proteins with prebiotic oligosaccharides

Diet is considered the most influential factor in modulating the gut microbiota but how dietary protein sources differ in their modulatory effects is not well understood. In this study, soy, meat (mixture of beef and pork), and fish proteins (experiment 1) and soy, milk (casein), and egg proteins (experiment 2) were fed to rats with cellulose (CEL) and raffinose (RAF); the microbiota composition and short-chain fatty acid concentration in the cecum were determined. Egg protein feeding decreased the concentration of acetic acid and the richness and diversity of the cecum microbiota. RAF feeding increased the concentrations of acetic and propionic acids and decreased the richness and diversity of the cecum microbiota. When fed with CEL, the abundance of Ruminococcaceae and Christensenellaceae, Akkermansiaceae and Tannerellaceae, and Erysipelotrichaceae enhanced with soy protein, meat and fish proteins, and egg protein, respectively. The effects of dietary proteins diminished with RAF feeding and the abundance of Bifidobacteriaceae, Erysipelotrichaceae, and Lachnospiraceae increased and that of Ruminococcaceae and Christensenellaceae decreased regardless of the protein source. These results indicate that, although the effect of prebiotics is more robust and distinctive, dietary protein sources may influence the composition and metabolic activities of the gut microbiota. The stimulatory effects of soy, meat, and egg proteins on Christensenellaceae, Akkermansiaceae, and Erysipelotrichaceae deserve further examination to better elucidate the dietary manipulation of the gut microbiota

The Relationship between Uterine, Fecal, Bedding, and Airborne Dust Microbiota from Dairy Cows and Their Environment: A Pilot Study

Simple Summary After calving, dairy cows face the risk of negative energy balance, inflammation, and immunosuppression, which may result in bacterial infection and disruption of the normal microbiota, thus encouraging the development of metritis and endometritis. This study characterized uterine, fecal, bedding, and airborne dust microbiota from postpartum dairy cows and their environment during summer and winter. The results clarify the importance of microbiota in cowshed environments, i.e., bedding and airborne dust, in understanding the postpartum uterine microbiota of dairy cows. Abstract The aim of this study was to characterize uterine, fecal, bedding, and airborne dust microbiota from postpartum dairy cows and their environment. The cows were managed by the free-stall housing system, and samples for microbiota and serum metabolite assessment were collected during summer and winter when the cows were at one and two months postpartum. Uterine microbiota varied between seasons; the five most prevalent taxa were Enterobacteriaceae, Moraxellaceae, Ruminococcaceae, Staphylococcaceae, and Lactobacillaceae during summer, and Ruminococcaceae, Lachnospiraceae, Bacteroidaceae, Moraxellaceae, and Clostridiaceae during winter. Although Actinomycetaceae and Mycoplasmataceae were detected at high abundance in several uterine samples, the relationship between the uterine microbiota and serum metabolite concentrations was unclear. The fecal microbiota was stable regardless of the season, whereas bedding and airborne dust microbiota varied between summer and winter. With regards to uterine, bedding, and airborne dust microbiota, Enterobacteriaceae, Moraxellaceae, Staphylococcaceae, and Lactobacillaceae were more abundant during summer, and Ruminococcaceae, Lachnospiraceae, Bacteroidaceae, and Clostridiaceae were more abundant during winter. Canonical analysis of principal coordinates confirmed the relationship between uterine and cowshed microbiota. These results indicated that the uterine microbiota may vary when the microbiota in cowshed environments changes

Cyclic nigerosylnigerose ameliorates DSS-induced colitis with restoration of goblet cell number and increase in IgA reactivity against gut microbiota in mice

Cyclic nigerosylnigerose (CNN) is a cyclic oligosaccharide. Oral administration of CNN promotes immunoglobulin A (IgA) secretion in the gut. IgA is a major antibody secreted into the gut and plays a crucial role in suppressing gut inflammation due to commensal gut microbiota. To investigate the effect of administration of CNN to promote IgA secretion on gut inflammation, experimental colitis was induced with dextran sulfate sodium (DSS) in Balb/c mice after 6 weeks of CNN pre-feeding. The severity of colitis was evaluated based on a disease activity index (DAI), the gene expression of inflammatory cytokines, and a histological examination. The CNN-treated mice with DSS-induced colitis (CNN-DSS group) showed significantly lower DAI scores and mRNA levels of interleukin-1 compared with the CNN-untreated mice with DSS-induced colitis (DSS group). Histological examination of the colon revealed that the pathological score was significantly lower in the CNN-DSS group compared with the DSS group due to the reduced infiltration of immune cells. The number of goblet cells was significantly higher in the CNN-DSS group compared with the DSS group. The IgA concentration and the ratio of microbiota coated with IgA were evaluated in the cecal content. Although there was no difference in the IgA concentration among groups, a higher proportion of cecal microbiota were coated with IgA in the CNN-DSS group compared with that in the DSS group. These results suggest that CNN might preserve goblet cells in the colon and promote IgA coating of gut microbiota, which synergistically ameliorate gut inflammation in mice with DSS-induced colitis