A real‐time PCR assay for the differentiation of Candida species

Aims: We established a real‐time PCR assay for the detection and strain identification of Candida species and demonstrated the ability to differentiate between Candida albicans the most common species, and also Candida parapsilosis, Candida glabrata, Candida tropicalis and Candida dubliniensis by LightCycler PCR and melting curve analysis. Methods and Results: The DNA isolation from cultures and serum was established using the QIAmp Tissue Kit. The sensitivity of the assay was ≥ 2 genome equivalents/assay. It was possible to differentiate all investigated Candida species by melting curve analysis, and no cross‐reaction to human DNA or Aspergillus species could be observed. Conclusions: The established real‐time PCR assay is a useful tool for the rapid identification of Candida species and a base technology for more complex PCR assays. Significance and Impact of the Study: We carried out initial steps in validation of a PCR assay for the detection and differentiation of medically relevant Candida species. The PCR was improved by generating PCR standards, additional generation of melting curves for species identification and the possibility to investigate different specimens simultaneously.     

Functional genomic analysis of the Bacillus subtilis Tat pathway for protein secretion

Protein secretion from Bacillus species is a major industrial production tool with a market of over $1 billion per year. However, standard export technologies, based on the well-characterised general secretory (Sec) pathway, are frequently inapplicable for the production of proteins. The recently discovered twin-arginine translocation (Tat) pathway offers additional potential to transport proteins. Here we review the use of functional genomic and proteomic approaches to explore the Tat pathway of Bacillus subtilis. The properties of Tat pathway components and the twin-arginine signal peptides that direct proteins into this pathway are discussed. Where appropriate, a comparison is made with Tat systems from other organism, such as Escherichia coli. Recent findings with the latter organism in particular provide proof-of-principle that the Tat pathway can be exploited for the production of Sec-incompatible proteins.     

One of Two OsmC Homologs in Bacillus subtilis Is Part of the ςB-Dependent General Stress Regulon

In this report we present the identification and analysis of two Bacillus subtilis genes, yklA and ykzA, which are homologous to the partially RpoS-controlled osmC gene from Escherichia coli. The yklA gene is expressed at higher levels in minimal medium than in rich medium and is driven by a putative vegetative promoter. Expression of ykzA is not medium dependent but increases dramatically when cells are exposed to stress and starvation. This stress-induced increase in ykzA expression is absolutely dependent on the alternative sigma factor ς^B, which controls a large stationary-phase and stress regulon. ykzA is therefore another example of a gene common to the RpoS and ς^B stress regulons of E. coli and B. subtilis, respectively. The composite complex expression pattern of the two B. subtilis genes is very similar to the expression profile of osmC in E. coli.     

Common sulfoglycolipid receptor for mycoplasmas involved in animal and human infertility

Sulfoglycolipids are ubiquitous components of the male germ cell membrane. Sulfogalactoglycerolipid (SGG) is restricted to mammalian cells and has recently been implicated in sperm/egg interactions. Mycoplasma infections have been implicated in infertility in a variety of species, including humans. Four such species-specific mycoplasmas, Ureaplasma urealyticum and Mycoplasma hominis (humans), Mycoplasma pulmonis (rodents), and Ureaplasma diversum (cattle) are not shown to specifically recognize SGG and the sphingolipid counterpart, sulfogalactosyl ceramide. This glycolipid receptor binding may relate to the reproductive pathogenesis of these organisms.     

Mycoplasma phocidae sp. nov., isolated from harbor seals (Phoca vitulina L.).

In 1979 and 1980, more than 400 harbor seals (Phoca vitulina) along the New England coast of the United States died of epizootic pneumonia that was attributed to an influenza virus. Six mycoplasma isolates that were recovered from the respiratory tracts of affected seals were investigated and were found to be serologically identical and distinct from previously described species. These isolates required serum for growth, did not possess a cell wall, and did not hydrolyze urea. Arginine was hydrolyzed, glucose was not fermented, film and spots were observed on horse serum agar, phosphatase was produced, tetrazolium was not reduced, and serum and casein were not digested. The guanine-plus-cytosine content of the DNA was 27.8 mol%. We propose the name Mycoplasma phocidae for these isolates. The type strain of M. phocidae is strain 105 (= ATCC 33657).     

短梗霉产liamocins研究进展

短梗霉真菌（Aureobasidium spp.）是一种世界性的酵母样真菌,因其产生黑色素而被称为黑酵母。短梗霉的许多菌株都能分泌细胞外脂质liamocins。Liamocins具有表面活性、良好的抗癌和抗菌活性。本文综述了分泌liamocins的短梗霉的多样性及影响其产生liamocins的因素,总结了liamocins生物合成途径的研究进展,并对短梗霉真菌合成liamocins的进一步研究提出了建议。     

Lack of an association of PD-1 and its ligand genes with Behcet's disease in a Chinese Han population

Background

Behcet''s disease is a chronic, multi-systemic autoimmune disease. Programmed cell death 1 (PD-1) gene is one of non-human leucocyte antigen genes. It has been demonstrated to be associated with several autoimmune diseases. However, only a few studies have addressed the association of ligand genes of PD-1, PD-L1 and PD-L2 with autoimmune disease. The purpose of this study was to analyze the potential association of the PD-1 and its ligand genes with Behcet''s disease in a Chinese Han population.

Methodology/Principal Findings

Four single-nucleotide polymorphism (SNPs) rs2227981 and rs10204525 of PD-1, rs1970000 of PD-L1 and rs7854303 of PD-L2 were genotyped in 405 Behcet''s patients and 414 age-, sex-, ethnic-matched healthy controls using polymerase chain reaction-restriction fragment length polymorphism assay. The results revealed that there were no significant differences in the genotype and allele frequencies of PD-1 rs2227981 and rs10204525 between the Behcet''s patients and controls. A similar result was found for PD-L1 rs1970000 versus healthy controls. Only the C allele and the CC genotype of PD-L2 rs7854303 were identified in patients and controls. Stratification analysis based on gender and clinical findings did not show any associations between PD-1 or its ligand polymorphisms and Behcet''s disease.

Conclusions/Significance

None of the currently studied SNPs, PD-1 rs2227981 and rs10204525, PD-L1 rs1970000 and PD-L2 rs7854303, are associated with the susceptibility to Behcet''s disease in a Chinese Han population. More studies are needed to confirm these findings in Behcet''s patients with other ethnic backgrounds.     

Environmental salinity determines the specificity and need for Tat-dependent secretion of the YwbN protein in Bacillus subtilis

Twin-arginine protein translocation (Tat) pathways are required for transport of folded proteins across bacterial, archaeal and chloroplast membranes. Recent studies indicate that Tat has evolved into a mainstream pathway for protein secretion in certain halophilic archaea, which thrive in highly saline environments. Here, we investigated the effects of environmental salinity on Tat-dependent protein secretion by the Gram-positive soil bacterium Bacillus subtilis, which encounters widely differing salt concentrations in its natural habitats. The results show that environmental salinity determines the specificity and need for Tat-dependent secretion of the Dyp-type peroxidase YwbN in B. subtilis. Under high salinity growth conditions, at least three Tat translocase subunits, namely TatAd, TatAy and TatCy, are involved in the secretion of YwbN. Yet, a significant level of Tat-independent YwbN secretion is also observed under these conditions. When B. subtilis is grown in medium with 1% NaCl or without NaCl, the secretion of YwbN depends strictly on the previously described "minimal Tat translocase" consisting of the TatAy and TatCy subunits. Notably, in medium without NaCl, both tatAyCy and ywbN mutants display significantly reduced exponential growth rates and severe cell lysis. This is due to a critical role of secreted YwbN in the acquisition of iron under these conditions. Taken together, our findings show that environmental conditions, such as salinity, can determine the specificity and need for the secretion of a bacterial Tat substrate.     

Aspergillus in the Intensive Care Unit

Invasive aspergillosis (IA), the most life-threatening form of aspergillosis, has become a major opportunistic fungal disease in immunocompromised patients. In high-risk patients with hematologic malignancies, IA appears to decline with the use of mold-active antifungal prophylaxis, but the situation is less clear in other patient groups at risk for IA, and precise epidemiologic data from patients treated in intensive care units (ICUs) are lacking. Most Aspergillus culture isolates from nonsterile body sites do not represent disease, but isolation of Aspergillus in critically ill patients is a marker of poor prognosis and is associated with high mortality regardless of invasion or colonization. This review presents current information on epidemiology, risk factors, and diagnosis, and discusses treatment options for patients with IA in the ICU.