Project description:We found that in rodents, b-cell mass expansion during pregnancy and obesity is associated with changes in the expression of a group of islet microRNAs. We were able to reproduce in isolated pancreatic islets the decrease of miR-338-3p level observed in gestation and obesity by activating the G-protein coupled estrogen receptor GPR30 and the GLP1 receptor. Blockade of miR-338-3p in b-cells using specific anti-miR molecules mimicked gene expression changes occurring during b-cell mass expansion and resulted in increased proliferation and improved survival both in vitro and in vivo. These findings point to a major role for miR-338-3p in compensatory b-cell mass expansion occurring under different insulin resistance states.
Project description:Few studies have assessed the patterns of parasite populations of rodents over a longitudinal gradient in Chile. In this work, the gastrointestinal helminthic fauna of invasive rodents in Chile was examined to assess the association between their presence/absence and abundance with latitude, host sex, and host body condition, and to assess the coexistence and correlation of the abundance between parasite species. Rodents were obtained from 20 localities between 33 and 43°S. Helminths were extracted from the gastrointestinal tract and identified morphologically. Overall, 13 helminth taxa were obtained. The most frequently identified parasite species was Heterakis spumosa, and the most abundant was Syphacia muris, while Physaloptera sp. was the most widely distributed. No locality presented with a coexistence that was different from that expected by chance, while the abundance of five helminthic species correlated with the abundance of another in at least one locality, most likely due to co-infection rather than interaction. Host sex was associated with parasite presence or abundance, and female sex-biased parasitism was notably observed in all cases. Body condition and latitude presented either a positive or negative association with the presence or abundance of parasites depending on the species. It is notable that the likely native Physaloptera sp. is widely distributed among invasive rodents. Further, gravid females were found, suggesting spillback of this species to the native fauna. The low frequency and abundance of highly zoonotic hymenolepid species suggest that rodents are of low concern regarding gastrointestinal zoonotic helminths.
Project description:The inability of the beta-cell to meet the demand for insulin brought about by insulin resistance leads to type 2 diabetes. In adults, beta-cell replication is one of the mechanisms thought to cause the expansion of beta-cell mass. Efforts to treat diabetes require knowledge of the pathways that drive facultative beta-cell proliferation in vivo. A robust physiological stimulus of beta-cell expansion is pregnancy, and identifying the mechanisms underlying this stimulus may provide therapeutic leads for the treatment of type 2 diabetes. The peak in beta-cell proliferation during pregnancy occurs on day 14.5 of gestation in mice. Using advanced genomic approaches, we globally characterize the gene expression signature of pancreatic islets on day 14.5 of gestation during pregnancy. We identify a total of 1,907 genes as differentially expressed in the islet during pregnancy. We demonstrate that the islet's ability to compensate for relative insulin deficiency during metabolic stress is associated with the induction of both proliferative and survival pathways. A comparison of the genes induced in three different models of islet expansion suggests that diverse mechanisms can be recruited to expand islet mass. The identification of many novel genes involved in islet expansion during pregnancy provides an important resource for diabetes researchers to further investigate how these factors contribute to the maintenance of not only islet mass, but ultimately beta-cell mass.
Project description:The Norway rat has important impacts on our life. They are amongst the most used research subjects, resulting in ground-breaking advances. At the same time, wild rats live in close association with us, leading to various adverse interactions. In face of this relevance, it is surprising how little is known about their natural behaviour. While recent laboratory studies revealed their complex social skills, little is known about their social behaviour in the wild. An integration of these different scientific approaches is crucial to understand their social life, which will enable us to design more valid research paradigms, develop more effective management strategies, and to provide better welfare standards. Hence, I first summarise the literature on their natural social behaviour. Second, I provide an overview of recent developments concerning their social cognition. Third, I illustrate why an integration of these areas would be beneficial to optimise our interactions with them.
Project description:BackgroundMurine kobuviruses (MuKV) are newly recognized picornaviruses first detected in murine rodents in the USA in 2011. Little information on MuKV epidemiology in murine rodents is available. Therefore, we conducted a survey of the prevalence and genomic characteristics of rat kobuvirus in Guangdong, China.ResultsFecal samples from 223 rats (Rattus norvegicus) were collected from Guangdong and kobuviruses were detected in 12.6% (28) of samples. Phylogenetic analysis based on partial 3D and complete VP1 sequence regions showed that rat kobuvirus obtained in this study were genetically closely related to those of rat/mouse kobuvirus reported in other geographical areas. Two near full-length rat kobuvirus genomes (MM33, GZ85) were acquired and phylogenetic analysis of these revealed that they shared very high nucleotide/amino acids identity with one another (95.4%/99.4%) and a sewage-derived sequence (86.9%/93.5% and 87.5%/93.7%, respectively). Comparison with original Aichivirus A strains, such human kobuvirus, revealed amino acid identity values of approximately 80%.ConclusionOur findings indicate that rat kobuvirus have distinctive genetic characteristics from other Aichivirus A viruses. Additionally, rat kobuvirus may spread via sewage.
Project description:Inflammation is a key component of pathological angiogenesis. Here we induce cornea neovascularisation using sutures placed into the cornea, and sutures are removed to induce a regression phase. We used whole transcriptome microarray to monitor gene expression profies of several genes
Project description:Individual differences in behaviors are seen across many species, and investigations have focused on traits linked to aggression, risk taking, emotionality, coping styles, and differences in cognitive systems. The current study investigated whether there were individual differences in proactive interference tasks in rats (Rattus Norvegicus), and tested hypotheses suggesting that these tasks should load onto a single factor and there should be clusters of rats who perform well or poorly on these tasks. The performance of 39 rats was tested across three learning tasks that all involved disengagement from an irrelevant previously learned stimulus to a relevant stimulus: latent inhibition (LI), partial reinforcement extinction effect (PREE), and reversal learning (RL). An exploratory factor analysis revealed the existence of one factor underlying performance. A cluster analysis revealed the existence of sets of rats displaying either weak LI and strong PREE and RL effects, or vice versa. These findings suggest that proactive interference may be based on a single underlying psychological system in rats.