Circadian control of interferon-sensitive gene expression in murine skin.

The circadian clock coordinates a variety of immune responses with signals from the external environment to promote survival. We investigated the potential reciprocal relationship between the circadian clock and skin inflammation. We treated mice topically with the Toll-like receptor 7 (TLR7) agonist imiquimod (IMQ) to activate IFN-sensitive gene (ISG) pathways and induce psoriasiform inflammation. IMQ transiently altered core clock gene expression, an effect mirrored in human patient psoriatic lesions. In mouse skin 1 d after IMQ treatment, ISGs, including the key ISG transcription factor IFN regulatory factor 7 (Irf7), were more highly induced after treatment during the day than the night. Nuclear localization of phosphorylated-IRF7 was most prominently time-of-day dependent in epidermal leukocytes, suggesting that these cell types play an important role in the diurnal ISG response to IMQ. Mice lacking Bmal1 systemically had exacerbated and arrhythmic ISG/Irf7 expression after IMQ. Furthermore, daytime-restricted feeding, which affects the phase of the skin circadian clock, reverses the diurnal rhythm of IMQ-induced ISG expression in the skin. These results suggest a role for the circadian clock, driven by BMAL1, as a negative regulator of the ISG response, and highlight the finding that feeding time can modulate the skin immune response. Since the IFN response is essential for the antiviral and antitumor effects of TLR activation, these findings are consistent with the time-of-day-dependent variability in the ability to fight microbial pathogens and tumor initiation and offer support for the use of chronotherapy for their treatment

Development and evaluation of a novel dietary bisphenol A (BPA) exposure risk tool

Background: Exposure to endocrine disrupting chemicals such as bisphenol A (BPA) is primarily from the diet through canned foods. Characterizing dietary exposures can be conducted through biomonitoring and dietary surveys; however, these methods can be time-consuming and challenging to implement. Methods: We developed a novel dietary exposure risk questionnaire to evaluate BPA exposure and compared these results to 24-hr dietary recall data from participants (n = 404) of the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) study, a dietary clinical trial, to validate questionnaire responses. High BPA exposure foods were identified from the dietary recalls and used to estimate BPA exposure. Linear regression models estimated the association between exposure to BPA and questionnaire responses. A composite risk score was developed to summarize questionnaire responses. Results: In questionnaire data, 65% of participants ate canned food every week. A composite exposure score validated that the dietary exposure risk questionnaire captured increasing BPA exposure. In the linear regression models, utilizing questionnaire responses vs. 24-hr dietary recall data, participants eating canned foods 1–2 times/week (vs. never) consumed 0.78 more servings (p \u3c 0.001) of high BPA exposure foods, and those eating canned foods 3+ times/week (vs. never) consumed 0.89 more servings (p = 0.013) of high BPA exposure foods. Participants eating 3+ packaged items/day (vs. never) consumed 62.65 more total grams of high BPA exposure food (p = 0.036). Conclusions: Dietary exposure risk questionnaires may provide an efficient alternative approach to 24-hour dietary recalls to quantify dietary BPA exposure with low participant burden. Trial registration: The trial was prospectively registered at clinicaltrials.gov as NCT01826591 on April 8, 2013

Cell wall composition in Cryptococcus neoformans is media dependent and alters host response, inducing protective immunity

INTRODUCTION: OBJECTIVE: The purpose of this study was to determine how different media influenced the amount of chitin and chitosan in the cell wall, which in turn impacted the cell wall architecture and host response. METHODS: Yeast extract, peptone, and dextrose (YPD) and yeast nitrogen base (YNB) are two commonly used media for growing Cryptococcus before use in in vitro or in vivo experiments. As a result, RESULTS: We observed that the growth of wild-type CONCLUSION: These findings emphasize the importance of culture media and pH during growth in shaping the content and organization of th

Three Highly Conserved Proteins Catalyze the Conversion of UDP-N-Acetyl-D-Glucosamine to Precursors for the Biosynthesis of O antigen in Pseudomonas aeruginosa O11 and Capsule in Staphylococcus aureus Type 5 - Implications for the UDP-N-Acetyl-L-Fucosamine Biosynthetic Pathway*

N-Acetyl-l-fucosamine is a constituent of surface polysaccharide structures of Pseudomonas aeruginosa and Staphylococcus aureus. The three P. aeruginosa enzymes WbjB, WbjC, and WbjD, as well as the S. aureus homologs Cap5E, Cap5F, and Cap5G, involved in the biosynthesis of N-acetyl-l-fucosamine have been overexpressed and purified to near homogeneity. Capillary electrophoresis (CE), mass spectroscopy (MS), and nuclear magnetic resonance spectroscopy have been used to elucidate the biosynthesis pathway, which proceeds in five reaction steps. WbjB/Cap5E catalyzed 4,6-dehydration of UDP-N-acetyl-d-glucosamine and 3- and 5-epimerization to yield a mixture of three keto-deoxy-sugars. The third intermediate compound was subsequently reduced at C-4 to UDP-2-acetamido-2,6-dideoxy-l-talose by WbjC/Cap5F. Incubation of UDP-2-acetamido-2,6-dideoxy-l-talose (UDP-TalNAc) with WbjD/Cap5G resulted in a new peak separable by CE that demonstrated identical mass and fragmentation patterns by CE-MS/MS to UDP-TalNAc. These results are consistent with WbjD/Cap5G-mediated 2-epimerization of UDP-TalNAc to UDP-FucNAc. A nonpolar gene knockout of wbjB, the first of the genes associated with this pathway, was constructed in P. aeruginosa serotype O11 strain PA103. The corresponding mutant produced rough lipopolysaccharide devoid of B-band O antigen. This lipopolysaccharide deficiency could be complemented with P. aeruginosa wbjB or with the S. aureus homolog cap5E. Insertional inactivation of either the cap5G or cap5F genes abolished capsule polysaccharide production in the S. aureus strain Newman. Providing the appropriate gene in trans, thereby complementing these mutants, fully restored the capsular polysaccharide phenotype

A combined strategy for quantitative trait loci detection by genome-wide association

We applied a range of genome-wide association (GWA) methods to map quantitative trait loci (QTL) in the simulated dataset provided by the 12th QTLMAS workshop in order to derive an effective strategy.A variance component linkage analysis revealed QTLs but with low resolution. Three single-marker based GWA methods were then applied: Transmission Disequilibrium Test and single marker regression, fitting an additive model or a genotype model, on phenotypes pre-corrected for pedigree and fixed effects. These methods detected QTL positions with high concordance to each other and with greater refinement of the linkage signals. Further multiple-marker and haplotype analyses confirmed the results with higher significance. Two-locus interaction analysis detected two epistatic pairs of markers that were not significant by marginal effects. Overall, using stringent Bonferroni thresholds we identified 9 additive QTL and 2 epistatic interactions, which together explained about 12.3% of the corrected phenotypic variance.The combination of methods that are robust against population stratification, like QTDT, with flexible linear models that take account of the family structure provided consistent results. Extensive simulations are still required to determine appropriate thresholds for more advanced model including epistasis

The Widespread Multidrug-Resistant Serotype O12 <i>Pseudomonas aeruginosa</i> Clone Emerged through Concomitant Horizontal Transfer of Serotype Antigen and Antibiotic Resistance Gene Clusters

The O-specific antigen (OSA) in Pseudomonas aeruginosa lipopolysaccharide is highly varied by sugar identity, side chains, and bond between O-repeats. These differences classified P. aeruginosa into 20 distinct serotypes. In the past few decades, O12 has emerged as the predominant serotype in clinical settings and outbreaks. These serotype O12 isolates exhibit high levels of resistance to various classes of antibiotics. Here, we explore how the P. aeruginosa OSA biosynthesis gene clusters evolve in the population by investigating the association between the phylogenetic relationships among 83 P. aeruginosa strains and their serotypes. While most serotypes were closely linked to the core genome phylogeny, we observed horizontal exchange of OSA biosynthesis genes among phylogenetically distinct P. aeruginosa strains. Specifically, we identified a “serotype island” ranging from 62 kb to 185 kb containing the P. aeruginosa O12 OSA gene cluster, an antibiotic resistance determinant (gyrA(C248T)), and other genes that have been transferred between P. aeruginosa strains with distinct core genome architectures. We showed that these genes were likely acquired from an O12 serotype strain that is closely related to P. aeruginosa PA7. Acquisition and recombination of the “serotype island” resulted in displacement of the native OSA gene cluster and expression of the O12 serotype in the recipients. Serotype switching by recombination has apparently occurred multiple times involving bacteria of various genomic backgrounds. In conclusion, serotype switching in combination with acquisition of an antibiotic resistance determinant most likely contributed to the dissemination of the O12 serotype in clinical settings