Month: September 2020

Drosophila grh mutant embryos have slack and fragile cuticles, as well as “grainy” and discontinuous head skeletons. Null mutations are lethal, as the embryos fail to develop past the embryonic/larval transition point due to their extremely fragile epidermal barriers. These phenotypes clearly point to defects in the formation of chitin-based cuticular structures in grh mutant embryos. Which encodes dopa decarboxylase, an enzyme required to generate the reactive quinone molecules used to cross-link chitin fibers and proteins in the Drosophila cuticle. Furthermore, grh embryos are permeable to exogenously applied dyes, and the removal of GRH from imaginal disc cells results in reduced expression of at least two cell-adhesion genes. These findings suggest that the paracellular integrity of the epithelial barrier underlying the cuticle becomes compromised in Drosophila grh mutants. In addition to the developmental functions of GRH in Drosophila, it is also necessary for the proper expression of several cuticular-barrier genes that are activated during the regenerative process following epidermal wounding. GRH family proteins are also important for epidermal-barrier formation in the distantly related invertebrate C. elegans. RNAi targeted against Ce-Grh-1 results in embryos with a fragile and puckered hypodermis – a similar phenotype to that seen in Drosophila. Ce-Grh-1 binds the same palindromic consensus DNA sequences as Drosophila GRH, and the Ddc gene in C. elegans has GRH binding sites upstream of its promoter. Strikingly, conservation of GRH family transcription factor function extends to vertebrates as well, despite vast differences in the structural components of epidermal barriers between and within protostome and deuterostome animals. In Xenopus laevis, expression of a dominant negative form of XGRHL1 leads to a malformed epidermis, partly due to lowered expression of keratin. While the DNA-binding specificity of GRH family proteins has been conserved between protostome and deuterostome animals, the downstream effectors of GRH-like proteins in distantly related species do not appear to be homologous, but instead carry out analogous functions suited to the specific barrier being generated or GDC-0879 905281-76-7 regenerated after wounding. For instance, the epidermal defects in Grhl3-deficient mice correlate with reduced levels of transglutaminase 1 transcription, as well as reduced transcription for many genes that are structural barrier components of differentiated corneocytes. Transglutaminase 1 is an enzyme necessary for the cross-linking of keratin and other proteins in the mammalian epidermis, and it plays an analogous role to that of dopa decarboxylase in the Drosophila cuticle. In sum, there exists a high-level functional conservation of GRH proteins as regulators of epidermal integrity and wound healing in both protostome and deuterostome animals, despite the significant structural differences in barrier composition across the animal kingdom. This functional conservation is reminiscent of other cases in which high-level transcription factor function has been conserved over great evolutionary time despite the drift of specific downstream effectors. Since the function of GRH-like proteins in epidermal-barrier formation and wound healing appears well conserved in triploblastic animals.

For hundreds of millions of years, have been regulating very similar developmental patterning or cell-type-specific properties during development – a striking NVP-BKM120 example of which is the conservation of GRH family function with respect to epithelial barrier formation in animals. It may be that the functions of animal transcription factors are somewhat more evolutionarily constrained than those of Fungi, and that Fungi are more likely to evolve new combinations of transcription factors to regulate core biological functions. As the world continues to focus on many recent findings concerning the pathogenic and adaptive mechanisms of foodborne S. Typhimurium and S. Enteritidis, the principal factors underlying the unique epidemiological pattern and disease manifestation of this virulent, human-restricted, intracellular pathogen, S. Typhi, remains intruiging. In recent years, increasing evidence has implicated carbon catabolism as a virulence determinant of human pathogens. The ability of pathogenic bacteria to metabolize various nutrients, especially carbon sources, is essential for the invasion, growth, survival and colonisation in intestinal and extra-intestinal sites in their hosts. To successfully colonise and persist in the various niches within the host during the course of infection, bacterial pathogens need to adjust and adapt their metabolic activity to the local nutrient availability. Nonetheless, as compared with the growing knowledge of molecular bacterial virulence and pathogenesis, research on pathogenic bacterial metabolism and persistence in the human host has progressed very little. S. Typhi exhibits unique characteristics as an intracellular human pathogen that are not observed in other human bacterial pathogens: it is human host restricted and incapable of infecting other living organisms; able to cause both acute and chronic infection, displaying various disease manifestations; and able to transform the human host into long-term asymptomatic carriage in the environment with periodical dissemination via urine and faeces. Therefore, it is important to understand the intracellular lifestyle of this unique pathogen. To do so, we employed highthroughput phenotypic microarray analysis to characterise the carbon metabolic capacity of S. Typhi in the human host. The novelty of this study is derived from the interesting and diverse background of each of the S. Typhi strains included in this work. These S. Typhi strains were carefully selected to include strains from Malaysia and Chile to determine whether there were any metabolic differences between the two areas of typhoid endemicity which are distantly separated. To explore our hypothesis that the metabolic capacity of the strains isolated from stool develops an adaptive persistence mechanism in the liver or gallbladder during chronic infection, these stool strains will differ from the strains isolated from the blood during acute systemic infection in the human host. A bacterial strain originated from a healthy human carrier was included in this study to contrast with the strains of transient chronic infection. The occurrence of S. Typhi in the environment is extremely rare, even though it is generally accepted that the pathogen could be transmitted via contaminated water and foods.

Some bacteria transferred during sexual activity cause substantial world-wide morbidity. In addition, the CS and distal urethras of healthy men at least episodically support bacterial communities. Lactobacillus spp. have been identified in urine and urethral swabs, and BV-associated taxa including Prevotella, Gardnerella and Sneathia are found in CS and urethral specimens from adult men. Although the role of bacteria in the male urethra is unknown, the CS microbiota has been hypothesized to mediate effects of circumcision on risk of HIV and other STI. A limitation in understanding the microbiota of the penis is the lack of data from healthy young men who have and or have not had partnered sexual experiences. These data would allow more thorough description of the microbiota of the urethra and CS, and could provide insight into changes associated with sexual exposures. To fill this gap, we collected urine and CS specimens from eighteen healthy 14–17 year old men with varied circumcision status and sexual histories. Sampling was repeated at monthly intervals to investigate stability of the microbiota over a three-month period. Bacteria were identified using multiple 16 S rRNA sequencing methods. Urine and corresponding CS specimens supported stable, but dissimilar microbiotas. Major urine taxa in most of the sexually experienced and inexperienced participants were members of the order Lactobacillialles. Finally, some bacteria were detected only in participants with histories of partnered sexual activity. The primer and barcode sequences were then trimmed from the remaining sequences using customized Perl scripts. Both the 16 S contigs from Sanger sequencing and 16 S raw sequences were classified with RDP Classifier v2.2 using a series of confidence cutoffs ranging from 0.6 to 0.9. For selected subset of genera member sequences were BLASTed against the SILVA database. Species-level PF-4217903 c-Met inhibitor assignments were decided based on near perfect alignments to top database matches and were manually examined for alignment quality. Multiple sequence alignments were produced using ClustalW with default parameters, and neighbor-joining phylogenic trees were constructed using PHYLIP. Principal coordinate analyses of microbial communities were performed using Unifrac. The above Unifrac analyses were also repeated by random sub-sampling from each specimen. Briefly, sequence reads were randomly extracted without replacement from each specimen and this procedure was repeated 100 times. The averaged sequence counts were used for Unifrac analyses. Microsoft EXCEL and customized scripts developed in the R statistical package were used for statistical analyses. To correct for multiple tests, false discovery rates were computed with the R package function qvalue. Wilcoxon’s rank sum test was used to assess comparisons of continuous variables between groups. The Wilcoxon’s signed rank test for paired data was used for comparisons between swab and urine samples from the same subject. Fisher’s exact test was used for comparisons of categorical variables between groups. Sørensen’s similarity index was calculated between either swab or urine specimens from different time points within each subject to assess intra-subject variability of microbiotas over time. Differences in the index between swab and urine samples were assessed using linear mixed-effects models.

Further studies attempt to combine omentum-wrapping with several other strategies, such as optimizing the microstructure of the L-CCH scaffold, incorporating neurotrophic agents, and seeding supportive cells. Rodent borne hantaviruses are the etiological agent of two zoonotic diseases: hemorrhagic fever with renal syndrome in Eurasia, and hantavirus cardiopulmonary syndrome in the Americas. The bank vole borne PUUV causes HFRS in Europe. Currently no specific treatment or US FDA-approved vaccines are available against HFRS/HCPS. While it has been shown that hantaviruses can deregulate human endothelial cell functions, activate unusual immune responses in patients, and interfere with several signaling pathways in human cells the exact Masitinib msds mechanism of symptoms associated with HFRS/HCPS still remains unknown. Interestingly, while hantaviruses cause a transient infection and disease in humans, infections of the natural rodent hosts seem to be chronic and asymptomatic. It is possible that PUUV and other hantaviruses have developed features that facilitate viral persistence, replication and spread, without harming the natural host. However, due to the lack of specific reagents, it has not been possible to analyze if PUUV interferes with bank vole cell functions, and consequently it is not known if PUUV affects infected cells in a species-specific manner. Activation of innate immune responses is crucial in order to eradicate virus infections. The induction of, as well as response to, type I IFNs during virus infection are important parts of the innate immunity. When pattern recognition receptors detect viruses in infected cells, they activate pathways leading to the induction and production of IFN-a/b. These IFNs then act on infected as well as non-infected bystander cells by inducing IFN-stimulated genes like Mx proteins, which possess antiviral features, thereby inhibiting viral replication and further spread. Consequently, most pathogenic viruses have evolved countermeasures which can inhibit induction of IFNs, and/or can inhibit IFN-induced activation of antiviral responses in infected cells. Understanding how zoonotic virus infections in natural hosts differ from human infections might give important clues to the mechanisms behind pathogenesis in humans. In order to study this there is a need for in vitro-models based on natural hosts cells. Here, we present a model for virus infection experiments in cells derived from bank voles and protocols for studies of bank vole innate immune activation. We here report that VEFs, isolated from bank vole embryos, are susceptible to infection with PUUV, and also to other bank vole borne viruses like TBEV, CPXV and LV, thereby providing the first in vitro-model for experimental studies of viruses having bank voles as a natural reservoir. Importantly, in addition to infection of VEFs with cell line adapted PUUV, successful infection was also established with wild-type PUUV. The bank vole IFN-b and Mx2 genes were partially sequenced, and Q-PCR protocols for quantification of gene expression were developed. Using these newly developed Q-PCR protocols, levels of IFN-b and Mx2 mRNA were analyzed in response to infection with CPXV, LV, PUUV-Kazan-E6 or TBEV.

The analyses uncovered that two subunits, an NBD and a conserved transmembrane protein, of the metal transporters and the biotin transporters, are related. Functional genomics then uncovered many more transporters of this type. The description in 2009 of ECF systems as a novel group of membrane transporters for many different substrates contradicted the dogma that ABC-type importers strictly depend on extracytoplasmic soluble solutebinding proteins for delivery of substrate and initiation of the transport cycle. Instead, ECF importers contain substrate-specific transmembrane proteins. S units are in most cases single small membrane proteins and have extremely high affinity for their substrates in the low nanomolar or picomolar range. The primary structures of the S components for different substrates are highly diverse. T components are moderately similar transmembrane proteins with strongly conserved amino acid signatures in a cytoplasmic loop. Since the A components contain the typical features of NBDs including the Walker A and B motifs, the LSGGQ signature sequence and the His motif, they are predicted to function as dimers as all ABC ATPases. The module composed of A and T units is called – for historical reasons – the “energy-coupling factor”. Another unprecedented finding was the fact that the ECF module is shared by several highly diverse S components in one subgroup of ECF transporters which are mainly found among gram-positive bacteria and archaea. Subgroup I comprises systems with a dedicated ECF module in gram-negative and gram-positive bacteria and in archaea. Notably, the S components of two bacterial cobalt transporters and the biotin transporter BioMNY of Reversine Aurora Kinase inhibitor Rhodobacter capsulatus, which are members of subgroup I, were shown by in vivo assays to have significant substrate-uptake activity in the absence of their cognate A- and T units. In contrast, analysis of vitamin uptake by subgroup II folate, pantothenate, riboflavin and thiamine transporters suggest that the corresponding S components FolT, PanT, RibU and ThiT do not function as transporters in a solitary state. Many questions regarding physical and functional interactions among the subunits of ECF transporters and their in vivo oligomeric state remain to be answered. Furthermore, the role of the T components is still not understood. Light-scattering experiments with purified subgroup II ECF transporters of L. lactis have revealed that the S, A1, A2 and T subunits mainly exist in a 1:1:1:1 stoichiometry in detergent solution. On the other hand, in vivo fluorescence analyses of the subgroup I biotin transporter of R. capsulatus suggest, that the S unit BioY oligomerizes in the living cell independent of the presence of the A and T components. This finding is indicative of a transporter complex with a higher-order structure in situ. The T components of ECF transporters may function as docking sites for the membrane-spanning S units and the cytoplasmic A units. Recent crystal structure analysis of the L. lactis S unit ThiT combined with sequence comparisons and mutant studies suggest that an Ala-X3-Ala signature in transmembrane helix I of the L. lactis S units is involved in S unit:T unit interactions.