Project description:BackgroundChina is characterized by complex topographic structure and dramatic palaeoclimatic changes, making species biogeography studies particularly interesting. Previous researchers have also demonstrated multiple species experienced complex population histories, meanwhile multiple shelters existed in Chinese mainland. Despite this, species phylogeography is still largely unexplored. In the present study, we used a combination of microsatellites and mitochondrial DNA (mtDNA) to investigate the phylogeography of the east Asian fish-eating bat (Myotis pilosus).ResultsPhylogenetic analyses showed that M. pilosus comprised three main lineages: A, B and C, which corresponded to distinct geographic populations of the Yangtze Plain (YTP), Sichuan Basin (SCB) and North and South of China (NSC), respectively. The most recent common ancestor of M. pilosus was dated as 0.25 million years before present (BP). Population expansion events were inferred for populations of Clade C, North China Plain region, Clade B and YunGui Plateau region at 38,700, 15,900, 4,520 and 4,520 years BP, respectively. Conflicting results were obtained from mtDNA and microsatellite analyses; strong population genetic structure was obtained from mtDNA data but not microsatellite data. The microsatellite data indicated that genetic subdivision fits an isolation-by-distance (IBD) model, but the mtDNA data failed to support this model.ConclusionsOur results suggested that Pleistocene climatic oscillations might have had a profound influence on the demographic history of M. pilosus. Spatial genetic structures of maternal lineages that are different from those observed in other sympatric bats species may be as a result of interactions among special population history and local environmental factors. There are at least three possible refugia for M. pilosus during glacial episodes. Apparently contradictory genetic structure patterns of mtDNA and microsatellite could be explained by male-mediated gene flow among populations. This study also provides insights on the necessity of conservation of M. pilosus populations to conserve this genetic biodiversity, especially in the areas of YTP, SCB and NSC regions.
Project description:Improving immune function during aging contributes to the extension of healthspan. However, little is known about interventions for overcoming immunosenescence. Here, we investigated whether syringaresinol (SYR), an activator of FOXO3, overcomes immunosenescence and the factors associated with this effect. To address this, we administered SYR to 42-week-old mice for 10 weeks and analyzed immunological parameters and the gut microbiota. Compared to control mice, SYR-treated mice exhibited reversal of the age-related changes in lymphocyte subsets—such as CD3+ T, CD19+ B and Foxp3+ regulatory T (Treg) cells—and T-cell function in vitro. SYR induced the expression of Bim as well as the activation of FOXO3 in Tregs, which probably regulated Treg homeostasis. Furthermore, SYR reduced the serum level of lipopolysaccharide-binding protein, an inflammatory marker, and enriched the gut microbiota with beneficial bacteria, Lactobacillus and Bifidobacterium, effects that were closely associated with the changes in lymphocyte subsets. Finally, SYR enhanced humoral immunity against influenza vaccination to the level of young control mice. Collectively, these findings indicate that SYR may rejuvenate immunosenescence by enhancing the immune response and modulating the gut microbiota, possibly affecting systemic inflammation, although the precise mechanism awaits further study, and suggest SYR to be a potent candidate for anti-immunosenescence intervention.
Project description:Resident macrophages are important for maintaining tissue homeostasis and for defence against infections, but their precise functions in different tissues are not fully elucidated.We have used high resolution quantitative proteomics to investigate the functions of splenic red pulp macrophages and peritoneal cavity macrophages in the steady-state. The validation of several proteins at cellular expression levels by the flow cytometry analysis was consistently in agreement with the proteomics data. Peritoneal macrophages were shown to be enriched in a number of key enzymes and metabolic pathways normally associated with the liver, such as metabolism of fructose, detoxification, nitrogen homeostasis and the urea cycle. Supporting observations in proteomics, we find that PM are able to utilise glutamine and glutamate which are rich in peritoneum for urea generation. In comparison, splenic red pulp macrophages were enriched in proteins important for adaptive immunity such as antigen presenting MHC molecules, in addition to proteins required for erythrocyte homeostasis and iron turnover. We also show that these tissue macrophages may utilise carbon and nitrogen substrates for different metabolic fates to support distinct tissue-specific roles. This study provides a valuable resource for biologists interested in the functions of tissue macrophages.