Project description:Ixodes pacificus, the vector of Borrelia burgdorferi (Bb) on the west coast, feeds on a variety of hosts including rodents, birds, and lizards. While rodents are reservoirs for Bb and can infect juvenile ticks, lizards are Bb-refractory. Despite the range of bloodmeals for I. pacificus, it is undetermined how larval host bloodmeal identity may affect future nymphal vector competence. Here, we conducted a transcriptome analysis on I. pacificus to determine whether and through what mechanisms host bloodmeal history affects vector competency of I. pacificus for the Lyme disease pathogen.
Project description:We found that mainstream cigarette smoking (4 cigarettes/day, 5 days/week for 2 weeks using Kentucky Research Cigarettes 3R4F) resulted in >20% decrease in the percentage of normal Paneth cell population in Atg16l1 T300A mice but showed minimal effect in wildtype littermate control mice, indicating that Atg16l1 T300A polymorphism confers sensitivity to cigarette smoking-induced Paneth cell damage. We performed cohousing experiments to test if Paneth cell phenotype is horizontally transmissible as is microbiota. Atg16l1 T300A and littermate controls that were exposed to cigarette smoking were used as microbiota donors, and these donor mice were exposed to smoking for 2 weeks prior to cohousing. Separate groups of Atg16l1 T300A and littermate controls that were not exposed to cigarette smoking were used as microbiota recipients. The microbiota recipients were co-housed with microbiota donors of the same genotype for 4 weeks, during this period the donors continued to be exposed to cigarette smoking. Cigarette smoking was performed using smoking chamber with the dosage and schedule as described above. At the end of the experiment, the fecal microbiota composition was analyzed by 16S rRNA sequencing.
Project description:Lizards cannot naturally regenerate limbs but are the closest known relatives of mammals capable of epimorphic tail regrowth. However, the mechanisms regulating lizard blastema derivation and chondrogenesis remain unclear. We utilized single-cell RNA sequencing analyses of regenerating lizard tails throughout the course of regeneration to assess diversity and heterogeneity in regeneating tail cell populations.
Project description:We profiled transcriptome and accessible chromatin landscapes in intestinal epithelial cells (IECs) from mice reared in the presence or absence of microbiota. We show that regional differences in gene transcription along the intestinal tract were accompanied by major alterations in chromatin organization. Surprisingly, we discovered that microbiota modify host gene transcription in IECs without significantly impacting the accessible chromatin landscape. Instead, microbiota regulation of host gene transcription might be achieved by differential expression of specific TFs and enrichment of their binding sites in nucleosome depleted CRRs near target genes. Our results suggest that the chromatin landscape in IECs is pre-programmed by the host in a region-specific manner to permit responses to microbiota through binding of open CRRs by specific TFs. mRNA and accessible chromatin (DNase-seq) profiles from colonic and ileal IECs were compared between conventionally-raised (CR), germ-free (GF), and conventionalized (CV) C57BL/6 mice.
Project description:Based on its phylogenetic relationship to monitor lizards (Varanidae), Gila monsters (Heloderma spp.), and the earless monitor Lanthanotus borneesis, the Chinese crocodile lizard, Shinisaurus crocodilurus, has been assigned to the Toxicofera clade, which comprises venomous reptiles. However, no data about composition and biological activities of its oral secretion have been reported. In the present study, a proteomic analysis of the mandibular gland of S. crocodilurus and, for comparison, of the herbivorous Solomon Island skink Corucia zebrata, was performed. Scanning electron microscopy (SEM) of the teeth from S. crocodilurus revealed a sharp ridge on the anterior surface, but no grooves, whereas those of C. zebrata possess a flattened crown with a pointed cusp. Proteomic analysis of their gland extracts provided no evidence of venom-derived peptides or proteins, strongly supporting the non-venomous character of these lizards.
Project description:Proteins are ubiquitous macromolecules displaying a vast repertoire of chemical and enzymatic functions making them suitable candidates for chemosignals used in intraspecific communication. Proteins are present in skin gland secretions of vertebrates but their identity, and especially, their functions, remain largely unknown. Many species of lizards possess femoral glands, i.e. epidermal organs primarily involved in the production and secretion of chemosignals playing a pivotal role in mate choice and intrasexual communication. The lipophilic fraction of femoral glands has been well studied in lizards. In contrast, proteins have been the focus of only a handful of investigations. Here, we study the identity, inter-individual expression patterns and functionality of proteins present in femoral glands of sand lizards (Lacerta agilis) by applying mass-spectrometry proteomics. Our results showed that the total number of proteins varied substantially among individuals. None of the identified femoral gland proteins could be directly linked to chemical communication in lizards, although this result hinges on protein annotation in databases in which squamate semiochemicals are poorly represented. In contrast to our expectations, proteins consistently expressed across individuals were related to immune system, antioxidant activity and lipid metabolism as the main functions, adding support to the hypothesis that proteins in reptilian epidermal glands have other functions besides chemical communication. Interestingly, we found that major histocompatibility complex class I (MHC) expression is enriched in femoral gland secretions. Previously, MHC was hypothesized to have been coopted to serve a semiochemical function in sand lizards, specifically in partner recognition. We speculate with the possibility that MHC proteins could be linked to semiochemical function in sand lizards.
Project description:We have previously demonstrated that the gut microbiota can play a role in the pathogenesis of conditions associated with exposure to environmental pollutants. It is well accepted that diets high in fermentable fibers such as inulin can beneficially modulate the gut microbiota and lessen the severity of pro-inflammatory diseases. Therefore, we aimed to test the hypothesis that hyperlipidemic mice fed a diet enriched with inulin would be protected from the pro-inflammatory toxic effects of PCB 126.