Metagenomic and Culturomics Analysis of Microbial Communities within Surface Sediments and the Prevalence of Antibiotic Resistance Genes in a Pristine River: The Zaqu River in the Lancang River Source Region, China.

Microbial communities inhabiting sedimentary environments in river source regions serve as pivotal indicators of pristine river ecosystems. While the correlation between antibiotic resistome and pathogenicity with core gut bacteria in humans is well established, there exists a significant knowledge gap concerning the interaction of antibiotic resistance genes (ARGs) and human pathogenic bacteria (HPB) with specific microbes in river source basins, often referred to as "terrestrial gut". Understanding the microbial composition, including bacteria and resident genetic elements such as ARGs, HPB, Mobile Genetic Elements (MGEs), and Virulence Factors (VFs), within natural habitats against the backdrop of global change, is imperative. To address this gap, an enrichment-based culturomics complementary along with metagenomics was conducted in this study to characterize the microbial biobank and provide preliminary ecological insights into profiling the dissemination of ARGs in the Lancang River Source Basin. Based on our findings, in the main stream of the Lancang River Source Basin, 674 strains of bacteria, comprising 540 strains under anaerobic conditions and 124 under aerobic conditions, were successfully isolated. Among these, 98 species were identified as known species, while 4 were potential novel species. Of these 98 species, 30 were HPB relevant to human health. Additionally, bacA and bacitracin emerged as the most abundant ARGs and antibiotics in this river, respectively. Furthermore, the risk assessment of ARGs predominantly indicated the lowest risk rank (Rank Ⅳ) in terms of endangering human health. In summary, enrichment-based culturomics proved effective in isolating rare and unknown bacteria, particularly under anaerobic conditions. The emergence of ARGs showed limited correlation with MGEs, indicating minimal threats to human health within the main stream of the Lancang River Source Basin.

Xiaoyaosan decoction regulates food intake and body weight via the leptin-leptin receptor-proopiomelanocortin pathway in rats with chronic immobilization stress.

OBJECTIVE: To evaluate the effects of the Xiaoyaosan (XYS) decoction on the food intake and body weight of rats with chronic immobilization stress (CIS), as well as the concentration of serum leptin and the expression of feeding-related neuropeptides [leptin receptor (Ob-R), proopiomelanocortin (POMC), and α-melanocyte-stimulating hormone (α-MSH)] in the hypothalamic arcuate nucleus (ARC). METHODS: We subjected rats to CIS for 3 h a day. The rats were randomly divided into the following groups: control group, 7-day stress group, 21-day stress group and XYS-treated group. The rats in the two stress groups were exposed to CIS for 7 or 21 d. The rats in the XYS-treated group were also exposed to CIS for 21 d and were intragastrically administered the XYS decoction before stress. The body weight and food intake of the rats were measured every day. The content of leptin in serum and α-MSH in the ARC were detected by ELISA, and the expression of neuropeptides in the ARC was assayed by immunofluorescence, Western blot and qRT-PCR. RESULTS: The food intake and body weight of rats exposed to CIS were lower than those of control rats. The serum leptin, and expression levels of Ob-R, POMC and α-MSH in the ARC were significantly higher than those in the control rats. Treatment with the XYS decoction improved the appetite and the body weight, and down-regulated serum leptin and Ob-R, POMC and α-MSH in hypothalamus ARC. CONCLUSION: The leptin-Ob-R-POMC pathway might be the part of the mechanism underlying XYS's improvement of somatic symptoms such as reduction in food intake and body weight related to CIS.