The case for microbial intervention at weaning.

Weaning, the transition from a milk-based diet to solid food, coincides with the most significant shift in gut microbiome composition in the lifetime of most mammals. Notably, this period also marks a "window of opportunity" where key components of the immune system develop, and host-microbe interactions shape long-term immune homeostasis thereby influencing the risk of autoimmune and inflammatory diseases. This review provides a comprehensive analysis of the changes in nutrition, microbiota, and host physiology that occur during weaning.

IgA deficiency destabilizes homeostasis toward intestinal microbes and increases systemic immune dysregulation.

The ability of most patients with selective immunoglobulin A (IgA) deficiency (SIgAD) to remain apparently healthy has been a persistent clinical conundrum. Compensatory mechanisms, including IgM, have been proposed, yet it remains unclear how secretory IgA and IgM work together in the mucosal system and, on a larger scale, whether the systemic and mucosal anti-commensal responses are redundant or have unique features. To address this gap in knowledge, we developed an integrated host-commensal approach combining microbial flow cytometry and metagenomic sequencing (mFLOW-Seq) to comprehensively define which microbes induce mucosal and systemic antibodies.

Arresting microbiome development limits immune system maturation and resistance to infection in mice.

Disruptions to the intestinal microbiome during weaning lead to negative effects on host immune function. However, the critical host-microbe interactions during weaning that are required for immune system development remain poorly understood. We find that restricting microbiome maturation during weaning stunts immune system development and increases susceptibility to enteric infection.

Diet-induced microbial autofluorescence confounds flow cytometry of ex vivo isolated fecal microbes.

Microbial flow cytometry is a powerful emerging technology with a broad range of applications including the study of complex microbial communities. Immunologists are increasingly using this technology to study antibody responses against pathogenic and commensal microbes. We employed microbial flow cytometry to quantify the proportion of fecal microbes bound by six different Ig isotypes: IgA, IgM, IgG1, IgG2b, IgG2c, and IgG3.

Gardnerella vaginalis and Prevotella bivia Trigger Distinct and Overlapping Phenotypes in a Mouse Model of Bacterial Vaginosis.

Background: Bacterial vaginosis (BV) is a common imbalance of the vaginal microbiota characterized by overgrowth of diverse Actinobacteria, Firmicutes, and Gram-negative anaerobes. Women with BV are at increased risk of secondary reproductive tract infections and adverse pregnancy outcomes. However, which specific bacteria cause clinical features of BV is unclear.

Host-Derived Sialic Acids Are an Important Nutrient Source Required for Optimal Bacterial Fitness In Vivo.

Unlabelled: A major challenge facing bacterial intestinal pathogens is competition for nutrient sources with the host microbiota.Vibrio cholerae is an intestinal pathogen that causes cholera, which affects millions each year; however, our knowledge of its nutritional requirements in the intestinal milieu is limited. In this study, we demonstrated that V.

Sialic acid catabolism and transport gene clusters are lineage specific in Vibrio vulnificus.

Sialic or nonulosonic acids are nine-carbon alpha ketosugars that are present in all vertebrate mucous membranes. Among bacteria, the ability to catabolize sialic acid as a carbon source is present mainly in pathogenic and commensal species of animals. Previously, it was shown that several Vibrio species carry homologues of the genes required for sialic acid transport and catabolism, which are genetically linked.

The chiral crown conformation in paddlewheel complexes.

Bimetallic paddlewheel complexes derived from imides of (S)-tert-leucine adopt 'chiral crown' configurations in which the four imide groups are projected in a chiral arrangement on one face, and the four tert-butyl groups are projected on the opposite face. In this contribution, the generality of the chiral crown conformation is examined through crystallographic studies where the metal and the nature of the chiral ligands are altered. Based upon these observations, a model is proposed to explain the factors which create bias for the chiral crown configuration.