Genomic evidence for the first symbiotic Deferribacterota, a novel gut symbiont from the deep-sea hydrothermal vent shrimp Rimicaris kairei

Comparative analysis of esophageal gland microbes between two body sizes of Gigantopelta aegis, a hydrothermal snail from the Southwest Indian Ridge

Microbial communities within animals provide nutritional foundation and energy supply for the hydrothermal ecosystem. The peltospirid snail Gigantopelta aegis forms large aggregation in the Longqi vent field on the Southwest Indian Ridge. This endemic species is characterized by a changeable diet and morphology, especially reflected in internal organs such as remarkably enlarged esophageal glands. Here, 16S full-length rRNA gene analysis was performed to compare the variations in esophageal gland microbiota between two body size groups (small and large) of G. aegis. Phyla Proteobacteria and Bacteroidetes were the dominant featured bacteria contributing to the microbial community. No significant differences between the small and large groups were revealed by the diversity index and principal component analysis (PCA) clustering. The differences were in the relative abundance of bacteria. Compared with small-sized snails, the larger ones housed more Thiogranum (9.94% to 34.86%) and fewer Sediminibacterium (29.38% to 4.54%). Functional prediction for all of the microbiota showed that the pathways related to metabolism appeared highly abundant in smaller G. aegis. However, for the larger ones, the most distinctive pathways were those of environmental information processing. Facultative symbiotic Sulfurovum was marked as a core node in the co-occurrence network and suggested an influence on habitat selection of G. aegis in hydrothermal fields. In summary, variations in bacteria composition and potential functions possibly reflected changes in the anatomical structure and dietary habits of G. aegis. These dominant bacteria shared capabilities in nutritional supplementation and ecological niche expansion in the host, potentially a key adaptation for hydrothermal survival.IMPORTANCEDominant in the Longqi hydrothermal vent Southwest Indian Ridge, Gigantopelta aegis was observed to undergo unique and significant morphological changes and diet shifts known as cryptometamorphosis. During this process, G. aegis developed a specialized bacteria-housing organ, the esophageal gland, in the later life stages. Our research discovered variations in esophageal gland microbes between different body size groups of snails. These bacteria were closely related to the development and health of G. aegis. Full-length 16S rRNA gene analysis revealed more Thiogranum and fewer Sediminibacterium, suggesting a potential association with environmental adaptation. In the small-sized group, the potential functions were enriched in metabolism, while in larger G. aegis individuals, predictions indicated adaptive functions such as environmental information processing. Also, symbiotic Sulfurovum could be one of the factors influencing the habitat selection of G. aegis. Understanding the complex relationship between benthic macrofauna and microbes helps us describe the mechanisms of survival in extreme environments.

Positive effects of extracellular polysaccharides from Paecilomyces hepiali on immune-enhancing properties by regulating gut microbiota in cyclophosphamide-induced mice

Paecilomyces hepiali is a precious health-care edible medicinal fungus with rich polysaccharides and exhibits various biological activities. Polysaccharides from P. hepiali fermentation broth (PHP) exhibits good immunomodulatory activity; however, the mechanism underlying PHP-mediated regulation of immunity and gut microbiota remains unclear. To reveal the mechanisms, PHP of different doses were used to intervene cyclophosphamide (CTX)-induced immunosuppressive model mice. The results revealed that PHP facilitated the secretion of serum cytokines, increased the mRNA and protein expression of TLR4/NF-κB signaling pathway. Furthermore, it improved the physical barrier function of the intestine by upregulating the expression of tight junction proteins. PHP increased the proliferation of beneficial bacteria, including, Actinobacteriota, Alistipes, Candidatus_Saccharimonas and unclassified_Clostridia_vadinBB60_group, and reduced the abundance of Proteobacteria, Deferribacterota, Mucispirillum and Escherichia_Shigella, promoted the production of short-chain fatty acids, which were positively associated with immune traits. Thus, as an immune enhancer, PHP has the potential to regulate the intestinal immune response in immunosuppressed mice through modulating gut microbiota.

Protective Effects of Four Structurally Distinct Sanshools Ameliorate Dextran Sodium Sulfate-Induced Ulcerative Colitis by Restoring Intestinal Barrier Function and Modulating the Gut Microbiota

Hydroxy-α-sanshool (HAS), hydroxy-β-sanshool (HBS), hydroxy-γ-sanshool (HRS), and γ-sanshool (RS) are the key components from the Zanthoxylum genus, processing a range of pharmacological activities. The present study investigated the protective capacities of four sanshools on a dextran sulfate sodium (DSS)-induced model of ulcerative colitis (UC). The results showed that sanshool administration alleviated the colitis symptoms by reducing body weight loss and disease activity index (DAI) score, increasing the colon length, and improving colonic injury and the change in immune organ weight. Furthermore, sanshools enhanced the antioxidant enzyme activities, and RS exhibited the lowest effect on the improvement in total antioxidative capacity (T-AOC) and antioxidant abilities compared to the other three sanshools. The p65 nuclear factor κB (p65 NFκB) signaling pathway was inhibited to prevent hyperactivation and decreased the production of inflammatory factors. The gut barrier function in DSS-induced mice was restored by increasing goblet cell number and levels of tight junction proteins (zonula occludens-1, occludin, and claudin-1), and the levels of protein in HAS and HRS groups were higher than that in the HBS group, significantly. The analysis of gut microbiota suggested that sanshool administration significantly boosted the abundance of Lachnospiraceae, Muribaculaceae, Oscillospiraceae, and Alistipes and reduced the level of Buchnera in colitis mice. Collectively, the sanshool treatment could ameliorate colitis by resisting colon injury and regulating intestinal barrier dysfunction and gut microbiota dysbiosis; meanwhile, HRS and HAS have better improvement effects.