Effects of underwater and semi-aquatic environments on gut tissue and microbiota of the mudskipper Boleophthalmus pectinirostris

Blueberry extract for the treatment of ischaemic stroke through regulating the gut microbiota and kynurenine metabolism

Although the gut microbiota and kynurenine (KYN) metabolism have significant protective effects against ischaemic stroke (IS), the exact mechanism has yet to be fully elucidated. Combined serum metabolomics and 16S rRNA gene sequencing were used to reveal the differences between the gut microbiota and metabolites in rats treated with or without blueberry extract. Faecal microbiota transplantation (FMT) was employed to validate the protective role of the gut microbiota in IS. Furthermore, the interaction between Prevotella and IS was also confirmed in patients. Rats with IS experienced neurological impairments accompanied by an impaired intestinal barrier and disturbed intestinal flora, which further contributed to heightened inflammatory responses. Furthermore, Prevotella played a critical role in IS pathophysiology, and a positive correlation between Prevotella and KYN was detected. The role of KYN metabolism in IS was further demonstrated by the finding that IDO was significantly upregulated and that the use of the IDO inhibitor, attenuated KYN metabolic pathway activity and ameliorated neurological damage in rats with IS. Prevotella intervention also significantly improved stroke symptoms and decreasing KYN levels in rats with IS. FMT showed that the beneficial effects of blueberry extract on IS involve gut bacteria, especially Prevotella, which were confirmed by microbiological analyses conducted on IS patients. Moreover, blueberry extract led to significant changes in kynurenic acid levels and tryptophan and IDO levels through interactions with Prevotella. Our study demonstrates for the first time that blueberry extract could modulate "intestinal microecology-KYN metabolism" to improve IS.

Effect of dietary chitosan on the growth performance, intestinal histology and growth-related gene expression in stellate sturgeon (Acipenser stellatus) juveniles

As sturgeon breeding has proliferated, there has been a heightened demand for growth stimulators in their diets. This study aimed to determine the impact of dietary chitosan on growth performance, whole-body proximate composition, growth-related gene expression, and intestinal histology in juvenile Acipenser stellatus. A total of 180 A. stellatus juveniles with an average weight of 31.90 ± 0.73 g were fed with diets containing 0 (control), 1.5, 3.0, 4.5, and 6.0 g chitosan.kg-1 basic diet for eight weeks. The findings revealed a significant enhancement in growth performance with rising chitosan concentrations. Furthermore, chitosan supplementation upregulated the expression of the growth hormone gene in both brain and liver tissues. In liver samples, the most pronounced expression of the insulin-like growth factor-1 gene was noted at 6.0 g chitosan.kg-1, while in brain samples, peak expressions were observed in both the 4.5 and 6.0 g chitosan.kg-1 treatments. While the whole-body proximate composition remained relatively stable, there was a notable decrease in whole-body lipids with the escalation of chitosan dosage. Intestinal villi dimensions, both height and width, were amplified in the chitosan-supplemented groups compared to controls. In summation, chitosan supplementation showed promise in bolstering growth performance, refining intestinal morphology, and enhancing growth-related gene expression. Analysis of the polynomial regression of weight gain and specific growth rate revealed that the optimum dietary chitosan requirements in A. stellatus were 5.32 and 5.21 g chitosan.kg-1, respectively.

Lactiplantibacillus plantarum Postbiotics Suppress Salmonella Infection via Modulating Bacterial Pathogenicity, Autophagy and Inflammasome in Mice

Our study aimed to explore the effects of postbiotics on protecting against Salmonella infection in mice and clarify the underlying mechanisms. Eighty 5-week-old C57BL/6 mice were gavaged daily with Lactiplantibacillus plantarum (LP)-derived postbiotics (heat-killed bacteria, LPBinactive; culture supernatant, LPC) or the active bacteria (LPBactive), and gavaged with Salmonella enterica Typhimurium (ST). The Turbidimetry test and agar diffusion assay indicated that LPC directly inhibited Salmonella growth. Real-time PCR and biofilm inhibition assay showed that LPC had a strong ability in suppressing Salmonella pathogenicity by reducing virulence genes (SopE, SopB, InvA, InvF, SipB, HilA, SipA and SopD2), pili genes (FilF, SefA, LpfA, FimF), flagellum genes (FlhD, FliC, FliD) and biofilm formation. LP postbiotics were more effective than LP on attenuating ST-induced intestinal damage in mice, as indicated by increasing villus/crypt ratio and increasing the expression levels of tight junction proteins (Occludin and Claudin-1). Elisa assay showed that LP postbiotics significantly reduced ST-induced inflammation by regulating the levels of inflammatory cytokines (the increased IL-4 and IL-10 and the decreased TNF-α) in serum and ileum (p < 0.05). Furthermore, LP postbiotics inhibited the activation of NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome by decreasing the protein expression of NLRP3 and Caspase-1, and the gene expression of Caspase-1, IL-1β and IL-18. Meanwhile, both LPC and LPB observably activated autophagy under ST infection, as indicated by the up-regulated expression of LC3 and Beclin1 and the downregulated p62 level (p < 0.05). Finally, we found that LP postbiotics could trigger an AMP-activated protein kinase (AMPK) signaling pathway to induce autophagy. In summary, Lactiplantibacillus plantarum-derived postbiotics alleviated Salmonella infection via modulating bacterial pathogenicity, autophagy and NLRP3 inflammasome in mice. Our results confirmed the effectiveness of postbiotics agents in the control of Salmonella infection.

One size does not fit all: Variation in anatomical traits associated with emersion behavior in mudskippers (Gobiidae: Oxudercinae)

Life histories involving transitions between differing habitats (i.e., aquatic to terrestrial or marine to freshwater) require numerous anatomical, physiological, and behavioral changes. Often, the traits associated with these changes are thought to come in suites, but all traits thought to be associated with particular life histories may not be required. While some traits are found in all species with a particular habitat transition, a grab bag approach may apply to other traits in that any trait may be sufficient for successful habitat transitions. We examine patterns of morphological traits associated with prolonged emersion in mudskipper, an amphibious fishes clade, where prolonged emersion appears twice. We test the evolutionary history of multiple characteristics associated with cutaneous respiration. We find most traits thought to be key for prolonged emersion show no phylogenetic signal and no tight correlation with prolonged emersion. Such traits appear in species with prolonged emersion but also non-emerging species. Only capillary density, which, when increased, allows for increased oxygen absorption, shows strong phylogenetic signal and correlation with prolonged emersion. Further experimental, functional genomics, and observational studies are needed to fully understand the mechanisms associated with each of these traits. With respect to traits associated with other particular behaviors, a comparative framework can be helpful in identifying evolutionary correlates.

Comparative Analysis of Intestinal Characteristics of Largemouth Bass (Micropterus salmoides) and Intestinal Flora with Different Growth Rates

To explore the causes of different growth rates among juvenile populations of largemouth bass, in the present study, a batch of largemouth bass juveniles reared under the same conditions were divided into a fast-growing group and a slow-growing group. We used histological, enzymatic and molecular biology methods to analyze and determine their histomorphological changes, digestive enzyme activity and intestinal floral composition. The fast-growing group had a significantly (p ≤ 0.01) greater intestinal fold height and muscle thickness than the slow-growing group. Lipase activity was significantly (p ≤ 0.01) higher in the fast-growing group than in the slow-growing group. Intestinal microbial analysis showed that the relative abundance of Actinobacteria and Halomonas in the fast-growing group was higher than that in the slow-growing group. This research shows that the differentiation of growth rates in juvenile largemouth bass populations is closely related to intestinal fold status, lipase activity, and intestinal flora.