Association Study of BMP4, IL6, Leptin, MMP3, and MTNR1B Gene Promoter Polymorphisms and Adolescent Idiopathic Scoliosis

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Differential sensitivity of the species of Candida parapsilosis sensu lato complex against statins

Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis are human fungal pathogens with clinical importance. The recently reclassified three closely related species have significant variation in virulence, clinical prevalence and susceptibility characteristics to different antifungal compounds. The aim of this study was to investigate the in vitro activity of atorvastatin and fluvastatin against C. metapsilosis, C. orthopsilosis and C. parapsilosis. Susceptibility tests showed that C. parapsilosis was the most sensitive while C. orthopsilosis was the least susceptible species to both drugs. On the basis of the differential sensitivity, we developed a simple, reliable and highly cost-effective plate assay to distinguish these closely related species. Applying this method, 54 isolates belonging to the C. parapsilosis sensu lato complex deposited in Szeged Microbial Collection could be sorted into the three species with 100 % probability

Candida parapsilosis produces prostaglandins from exogenous arachidonic acid and OLE2 is not required for their synthesis

Prostaglandins are C20 fatty acid metabolites with diverse biological functions. In mammalian cells, prostaglandins are produced from arachidonic acid (AA) via cyclooxygenases (COX1 and COX2). Although fungi do not possess cyclooxygenase homologues, several pathogenic species are able to produce prostaglandins from host-derived arachidonic acid. In this study, we characterized the prostaglandin profile of the emerging human pathogen Candida parapsilosis with HPLC-MS and compared it to that of C. albicans. We found that both species synthesized prostaglandins (mainly PGD2 and PGE2) from exogenous AA. Furthermore, as OLE2 has been associated with prostaglandin synthesis in C. albicans, we generated homozygous OLE2 deletion mutants in C. parapsilosis and examined their PGE2 production. However, the PGE2 production of the OLE2 KO strain was similar to that of wild type (WT), indicating that OLE2 is not required for prostaglandin synthesis in C. parapsilosis. Interestingly, analyses of the fatty acid composition of WT and OLE2 KO cells by gas chromatography (GC) highlighted the accumulation of palmitoleic and oleic acid in the OLE2 deletion mutant. The OLE2 KO cells were killed more efficiently by human monocytes-derived macrophages (MDMs) as well as induced higher interleukin-10 (IL-10) secretion, indicating that OLE2 affects the virulence of C. parapsilosis. Taken together, these results contribute to the better understanding of fatty acid biosynthesis pathways in C. parapsilosis

Characterization of Virulence Properties in the C. parapsilosis Sensu Lato Species

The C. parapsilosis sensu lato group involves three closely related species, C. parapsilosis sensu stricto, C . orthopsilosis and C . metapsilosis . Although their overall clinical importance is dramatically increasing, there are few studies regarding the virulence properties of the species of the psilosis complex. In this study, we tested 63 C. parapsilosis sensu stricto, 12 C . metapsilosis and 18 C . orthopsilosis isolates for the ability to produce extracellular proteases, secrete lipases and form pseudohyphae. Significant differences were noted between species, with the C . metapsilosis strains failing to secrete lipase or to produce pseudohyphae. Nine different clinical isolates each of C. parapsilosis sensu stricto, C . orthopsilosis and C . metapsilosis were co-cultured with immortalized murine or primary human macrophages. C. parapsilosis sensu stricto isolates showed a significantly higher resistance to killing by primary human macrophages compared to C . orthopsilosis and C . metapsilosis isolates. In contrast, the killing of isolates by J774.2 mouse macrophages did not differ significantly between species. However, C. parapsilosis sensu stricto isolates induced the most damage to murine and human macrophages, and C . metapsilosis strains were the least toxic. Furthermore, strains that produced lipase or pseudohyphae were most resistant to macrophage-mediated killing and produced the most cellular damage. Finally, we used 9 isolates of each of the C. parapsilosis sensus lato species to examine their impact on the survival of Galleria mellonella larvae. The mortality rate of G . mellonella larvae infected with C . metapsilosis isolates was significantly lower than those infected with C. parapsilosis sensu stricto or C . orthopsilosis strains. Taken together, our findings demonstrate that C . metapsilosis is indeed the least virulent member of the psilosis group, and also highlight the importance of pseudohyphae and secreted lipases during fungal-host interactions

Diagrammatic presentation of the occurrence of lipase-, protease- and pseudohyphae-producer strains in the <i>C. parapsilosis sensu lato</i> complex.

<p>n: number of isolates, upper number in fraction: number of pseudohypha-producer strains, lower number in fraction: number of pseudohypha negative strains.</p

Efficient treatment of a preclinical inflammatory bowel disease model with engineered bacteria

We developed an orally administered, engineered, bacterium-based, RNA interference-mediated therapeutic method to significantly reduce the symptoms in the most frequently used animal model of inflammatory bowel disease. This bacterium-mediated RNA interference strategy was based on the genomically stable, non-pathogenic E. coli MDS42 strain, which was engineered to constitutively produce invasin and the listeriolysin O cytolysin. These proteins enabled the bacteria first to invade the colon epithelium and then degrade in the phagosome. This allowed the delivery of a plasmid encoding small hairpin RNA (shRNA) targeting tumor necrosis factor (TNF) into the cytoplasm of the target cells. The expression levels of TNF and other cytokines significantly decreased upon this treatment in dextran sulfate sodium (DSS)-induced colitis, and the degree of inflammation was significantly reduced. With further safety modifications this method could serve as a safe and side effect-free alternative to biologicals targeting TNF or other inflammatory mediators

Comparative Phenotypic Analysis of the Major Fungal Pathogens Candida parapsilosis and Candida albicans.

Candida parapsilosis and Candida albicans are human fungal pathogens that belong to the CTG clade in the Saccharomycotina. In contrast to C. albicans, relatively little is known about the virulence properties of C. parapsilosis, a pathogen particularly associated with infections of premature neonates. We describe here the construction of C. parapsilosis strains carrying double allele deletions of 100 transcription factors, protein kinases and species-specific genes. Two independent deletions were constructed for each target gene. Growth in >40 conditions was tested, including carbon source, temperature, and the presence of antifungal drugs. The phenotypes were compared to C. albicans strains with deletions of orthologous transcription factors. We found that many phenotypes are shared between the two species, such as the role of Upc2 as a regulator of azole resistance, and of CAP1 in the oxidative stress response. Others are unique to one species. For example, Cph2 plays a role in the hypoxic response in C. parapsilosis but not in C. albicans. We found extensive divergence between the biofilm regulators of the two species. We identified seven transcription factors and one protein kinase that are required for biofilm development in C. parapsilosis. Only three (Efg1, Bcr1 and Ace2) have similar effects on C. albicans biofilms, whereas Cph2, Czf1, Gzf3 and Ume6 have major roles in C. parapsilosis only. Two transcription factors (Brg1 and Tec1) with well-characterized roles in biofilm formation in C. albicans do not have the same function in C. parapsilosis. We also compared the transcription profile of C. parapsilosis and C. albicans biofilms. Our analysis suggests the processes shared between the two species are predominantly metabolic, and that Cph2 and Bcr1 are major biofilm regulators in C. parapsilosis

Interactions of different <i>C. parapsilosis sensu lato</i> isolates (see Table S1.) with primary human monocyte-derived macrophages.

<p>(A) Killing efficiency of <i>C. parapsilosis sensu lato</i> species based on CFU-determinations (Cp, <i>C. parapsilosis sensu stricto</i>; Co, <i>C</i><i>. orthopsilosis</i>; Cm, <i>C</i><i>. metapsilosis</i>), (B) killing efficiency of lipase producer vs. non-producer and pseudohypha positive vs. negative strains in the <i>C. parapsilosis sensu lato</i> group [lip+, lipase positive (regardless of pseudohypha production); lip-, lipase negative; psh+, pseudohyphae positive (regardless of lipase production); psh-, pseudohyphae negative], (C) killing efficiency of lipase or pseudohyphae positive vs. negative isolates of <i>C. parapsilosis sensu stricto</i>, (D) killing efficiency of lipase or pseudohyphae producer vs. non-producer strains of <i>C</i><i>. orthopsilosis</i>, (E) host-cell damaging capacity of <i>C. parapsilosis sensu lato</i> species based on the release of LDH (lactate dehydrogenase), (F) host-cell damaging capacity of lipase or pseudohyphae producer vs. non-producer strains in the <i>C. parapsilosis sensu lato</i> group, (G) host-cell damaging capacity of lipase or pseudohyphae positive vs. negative isolates of <i>C. parapsilosis sensu stricto</i>, (H) host-cell damaging capacity of lipase or pseudohyphae producer vs. non-producer strains of <i>C</i><i>. orthopsilosis</i>. Cp, <i>C. parapsilosis sensu stricto</i>; Co, <i>C</i><i>. orthopsilosis</i>; Cm, <i>C</i><i>. metapsilosis</i>. Data points on graphs represent individual strains. Experiments were performed in triplicates. Data were analyzed by the Kruskal-Wallis test (A, E), the Mann-Whitney test (B, D, F, G, H) or the Wilcoxon rank sum test (C). * p<0.05, ** p<0.01, *** p<0.001.</p