Project description:Glutamate dehydrogenase (EC 1.4.1.2-4) from Peptoniphilus asaccharolyticus has been expressed as a selenomethionine-derivatized recombinant protein and diffraction-quality crystals have been grown that are suitable for structure determination. Preliminary structural analyses indicate that the protein assembles as a homohexameric enzyme complex in solution, similar to other bacterial and mammalian enzymes to which its sequence identity varies between 25 and 40%. The structure will provide insight into its preference for the cofactor NADH (over NADPH) by comparisons with the known structures of mammalian and bacterial enzymes.
Project description:Streptococcus gallolyticus subsp. gallolyticus is a commensal of the human gastrointestinal tract and a pathogen of infective endocarditis and other biofilm-associated infections with exposed collagen. Therefore, this study focuses on the characterization of the biofilm formation and collagen adhesion of S. gallolyticus subsp. gallolyticus under different conditions. It has been observed that lysozyme triggers biofilm formation divergently in the analyzed S. gallolyticus subsp. gallolyticus strains. The transcriptome analysis was performed for two strains which form more biofilm in the presence of lysozyme. Lysozyme leads to higher expression of genes of transcription and translation, of the dlt operon (cell wall modification), of hydrogen peroxide resistance proteins and of two immunity proteins which could be involved in biofilm formation. Furthermore, the adhesion ability of 73 different S. gallolyticus subsp. gallolyticus strains to collagen type I and IV was analyzed. High adhesion ability was observed for the strain UCN 34, whereas the strain DSM 16831 adhered only marginally to collagen. The full genome microarray analysis revealed strain-dependent gene expression due to adhesion. The expression of genes of a transposon and a phage region in strain DSM 16831 were increased, which corresponds to lateral gene transfer. Adherence to collagen leads to a change in the expression of genes of nutrients uptake in the strain UCN 34.
Project description:We have characterized miRNAs associated with equine seminal exosomes, and identified seminal exosomes eca-mir-128 to be specifically downregulated during equine arteritis virus long-term persistent infection in the reproductive tract of the stallion
Project description:The female reproductive tract is one of the major mucosal invasion site of HIV-1. This site has been neglected in previous HIV-1 vaccine studies. Immune responses in the female reproductive tract after systemic vaccination remain to be characterized. Using a modified vaccinia virus Ankara (MVA) as a vaccine model, we characterized specific immune responses in all compartments of the female reproductive tract (FRT) of non-human primates after systemic vaccination. Memory T cells were preferentially found in the lower tract (vagina and cervix), whereas antigen-presenting cells and innate lymphoid cells were mainly located in the upper tract (uterus and fallopian tubes). This compartmentalisation of immune cells in the FRT was supported by transcriptomic analyses and correlation network. Polyfunctional MVA-specific CD8+ T cells were detected in the blood, lymph nodes, vagina, cervix, uterus and fallopian tubes. Anti-MVA IgG and IgA were detected in cervicovaginal fluid after a second vaccine dose. Systemic vaccination with an MVA vector thus elicits cellular and antibody responses in the female reproductive tract.
Project description:Comparison of two Chlamydia-specific CD4 T cells that are dependent on iNOS to terminate Chlamydia replication in epithelial cells to two Chlamydia-specific CD4 T cells that are iNOS-independent: Chlamydia trachomatis urogenital serovars replicate predominately in epithelial cells lining the reproductive tract. This tissue tropism poses a unique challenge for the host immune system and vaccine development. Studies utilizing the Chlamydia muridarum mouse model have shown that CD4 T cells are critical and sufficient to clear primary genital tract infections. In vitro studies have shown that CD4 T cells terminate the infection in epithelial cells by up regulating epithelial iNOS transcription and nitric oxide production via IFN-gamma and T cell-epithelial cell interactions mediated by LFA-1-ICAM-1. This mechanism however is not critical as iNOS-deficient mice clear infections normally, and IFN-gamma deficient mice clear 99.9% of the infection with near normal kinetics. We recently showed that a subset of Chlamydia-specific CD4 T cell clones were able to terminate replication in epithelial cells using a mechanism that was independent of iNOS and IFN-gamma. That mechanism did not require physical lysis of infected cells, but instead required T cell degranulation. In this study we advanced that work using gene expression microarrays to compare CD4 T cell clones that are able to terminate epithelial replication via an iNOS-independent mechanism to iNOS-dependent CD4 T cell clones. Micro array experiments showed that Plac8 was differentially expressed by the T cell clones having the iNOS-independent mechanism. Plac8-deficient mice had significantly delayed clearance of C. muridarum genital tract infections, and that the large majority of Plac8-deficient mice treated with the iNOS-inhibitor N-monomethyl-L-arginine (MLA) were unable to resolve a C. muridarum genital tract infection over 8 weeks. These results demonstrate that there are two independent and redundant T cell mechanisms for clearing C. muridarum genital tract infections; one mechanism dependent on iNOS, the other mechanism dependent on Plac8. While T cells subsets have been defined by cytokine profiles, there are important subdivisions by effector functions, in this case CD4Plac8. Gene expression study using 4 experimental groups with 4 replicates each.