Search

The desynchronization of circadian rhythms affected by light may induce physiological and psychological disequilibrium. We aimed to elucidate changes of growth, depression-anxiety like behaviors, melatonin and corticosterone (CORT) secretion, and gut microbiota in rats influenced by long-term light inputs. Thirty male Sprague–Dawley rats were exposed to a 16/8 h light/dark regime for 8 weeks. The light period was set to 13 h of daylight with artificial light (AL group, n = 10), or with natural light (NL group, n = 10), or with mixed artificial-natural light (ANL group, n = 10), and 3 h of artificial night light after sunset. The obtained findings indicated that the highest weight gain and food efficiency were observed in the AL group and the lowest in NL group. In the behavioral tests, the NL and ANL groups showed lower anxiety level than AL group, and ANL groups showed lower depression level than AL group. The NL and ANL groups had delayed acrophases and maintained higher concentrations of melatonin compared to AL group. The circadian rhythm of CORT was only found in ANL group. At the phylum level, the mixed light contributed to a lower abundance of Bacteroidetes. The genus level results recommend a synergistic effect of artificial light and natural light on Lactobacillus abundance and an antagonistic effect on the Lachnospiraceae_NK4A136_group abundance. The study indicated that the mixture of artificial and natural light as well as the alignment of the proportions had beneficial influences on depression-anxiety-like levels, melatonin and corticosterone secretion, and the composition of the gut microbiota. Key points: • The mixed light can reduce the depression-anxiety level • The mixed light can maintain the secretion rhythm of melatonin and CORT • The mixed light can increase Lactobacillus and decrease Lachnospiraceae_NK4A136_group [ABSTRACT FROM AUTHOR]

As the core food crop of a bioregenerative life support system (BLSS), wheat is susceptible to pathogen infection due to the lack of effective microbial communities in the confined and isolated environment. Therefore, a thorough understanding of the dynamic changes in wheat rhizosphere fungi is of great significance for improving wheat production and ensuring the stability of the BLSS. In the current study, we collected samples of rhizosphere fungi in the four growth stages of wheat grown in the "Lunar Palace 365" experiment. We employed bioinformatics methods to analyze the samples' species composition characteristics, community network characteristics, and FUNGuild function analysis. We found that the species composition of rhizosphere fungi in the wheat at the tillering stage changed greatly in the closed and isolated environment, while the species composition in the seedling, flowering, and mature stage were relatively stable. The results of the FUNGuild function analysis showed that the functions of rhizosphere fungi changed during wheat development. The rhizosphere fungal community was centered on Ascomycota, Mortierellomycota, and Chytridiomycota, and the community showed the characteristics of a "small world" arrangement. The stage of wheat seedlings is characterized by a greater abundance, diversity, and complexity of the network of interactions in the rhizosphere mycorrhiza community, while the tillering stage exhibited a greater clustering coefficient. Based on the changes in species composition, guild function regulation, and community structure differences of the wheat rhizosphere fungi in the BLSS, our study identified the critical fungal species during wheat development, providing a reference for ensuring the health and yield of plants in the BLSS system. Key points: • The diversity, composition, FUNguild, and network structure of rhizosphere fungi were analyzed. • Ascomycota, Mortierellomycota, and Chytridiomycota were the center of the rhizosphere fungal community network. • The effects of different wheat developmental stages on the community composition, function, and network structure of rhizosphere fungi were examined. [ABSTRACT FROM AUTHOR]

Antibiotics have been shown to have a major impact on the composition and metabolism of gut microbiota, while unpredictable stress has been shown to have major influences on gut microbiota homeostasis. However, the impact of combination antibiotics (e.g. metronidazole and ciprofloxacin) on gut microbiota dysbiosis that is induced by stress remains unclear. Here, chronic unpredictable mild stress (CUMS) was used to simulate unpredictable stress, and Sprague–Dawley rats received antibiotics (metronidazole and ciprofloxacin) after CUMS. The weights and coefficients of the thymus, liver and spleen were analysed. 16S rRNA gene sequencing was performed to determine the gut microbiota in the colon, cecum and ileum. We found that antibiotics decreased the CUMS-induced increases in spleen coefficients. Short-term antibiotic exposure significantly increased the cecum and ileum microbiota richness and significantly increased the ileum microbiota diversity after CUMS. Long-term antibiotic exposure significantly decreased the colon microbiota diversity and significantly increased the ileum microbiota richness after CUMS. The impacts of antibiotic exposure on the microbiota compositions at the phylum and genus levels in different gut segments were different after CUMS. However, it is worth noting that the most differentially abundant bacteria in the colon, cecum and ileum were all Verrucomicrobia under long-term antibiotic exposure. Antibiotic exposure significantly increased the relative abundance of Lactobacillus in the colon and ileum and significantly increased the relative abundance of Akkermansia in the colon and cecum after CUMS. In conclusion, this study showed that metronidazole and ciprofloxacin differentially affected the CUMS-induced changes in the microbiota of the colon, cecum and ileum. Key points • The impacts of antibiotic exposure on the changes in microbiota that were induced by chronic unpredictable mild stress were analysed. • We collected rat gut microorganisms from the colon, cecum and ileum. • The diversities, compositions, functions and network structures were analysed. [ABSTRACT FROM AUTHOR]

In the present work, the biotransformation of ginsenosides in white ginseng roots was innovatively investigated using the aerobic fermentation by the co-cultivation of Bacillus subtilis and Trichoderma reesei. It is found that in the co-cultivation mode, the optimal nitrogen source was corn steep liquor, and the loading of ginseng powder and inoculation proportion of B. subtilis and T. reesei were 15 g/L and 1:4, respectively. The total ginsenoside yield and production of minor ginsenosides in the co-cultivation mode obviously enhanced in comparison to the monoculture mode. Meanwhile, the maximal total ginsenoside yield of 21.79% and high hydrolase activities were achieved using the staged inoculation at the inoculation proportion of 1:4 in the co-cultivation mode, the production of minor ginsenosides such as Rg3 and Rh1, Rh2 was significantly strengthened, and the pharmacological activities of the fermented solution obviously improved. The enhancement of ginsenoside transformation can be mainly attributed to hydrolysis of the produced hydrolases and metabolism of two probiotics. This result clearly reveals that using the staged inoculation in co-cultivation fermentation mode was favor of the ginsenoside biotransformation in ginseng due to non-synchronous cell growth and different metabolic pathways of both probiotics. This work can provide a novel method for enhancing ginsenoside transformation of ginseng. Key points • Co-cultivation fermentation significantly promoted ginsenoside biotransformation. • The staged inoculation in co-culture mode was an optimal operation method. • The pharmacological activity of the co-cultured solution was significantly enhanced. [ABSTRACT FROM AUTHOR]