Pathogenesis Of Microorganisms Research Articles

When to Die Is the Question: Need and Manipulation of Cell Death by Mycobacterium

Cell death is an entrenched event which helps to sustain cellular homeostasis and also provides protective immunity against invading microorganisms. Cell death plays a vital role in host defense as well as the pathogenesis of microorganisms. Intracellular pathogens such as Mycobacterium tuberculosis (Mtb) manipulate cell death pathways to evade host defense mechanisms for its survival and remained as one of the deadliest infectious diseases. There has been a paradigm shift in tuberculosis (TB) research towards host-directed therapy to restrain Mtb. Studying the host-pathogen interactions in view of various cell death modalities will help us identify better strategies to fight against not only Mtb but other intracellular pathogens as well. This brief review aimed to summarize current knowledge of various cell death modalities utilized by the host and Mtb that compete with each other in the battle for survival.

Cell Adhesion Assay to Study Leptospiral Proteins: An Approach to Investigate Host-Pathogen Interaction.

The adhesion of pathogenic bacteria to host cells and the extracellular matrix (ECM) is considered an important step in the pathogenesis of microorganisms. It has been described that Leptospira spp. bind to multiple receptors on host cells and to the ECM to initiate infection. Most studies of Leptospira adherence described until now have focused on the in vitro attachment of recombinant L. interrogans proteins to ECM components. These putative adhesins may be involved in the colonization of the host, contributing to the bacterial invasion process. Certainly, in vitro cell adhesion studies have contributed to the elucidation of leptospiral pathogenesis mechanisms. Here, we describe a cell adhesion assay that can be used for studying the interactions between putative leptospiral adhesins and host components.

Molecular detection of fungal and bacterial DNA from pustules in patients with palmoplantar pustulosis: special focus on Malassezia species.

Palmoplantar pustulosis (PPP) is a distinct, chronic skin disorder characterized by intraepidermal pustules on the palms and soles. It is hypothesized that microorganisms on the skin might induce the symptoms of PPP via inflammatory cell activation. However, the microbiota has not been studied in detail because of the assumption that the pustules in PPP are sterile. To elucidate the role of microorganisms in pathogenesis of PPP. PCR analysis was performed of microbial DNA fragments in the pustules of patients with PPP. The sequence of the D1/D2 LSU 26s rRNA gene and that of the 16S rRNA gene was used for fungal and bacterial DNA detection, respectively. In total, 71 samples were carefully collected from the pustules of patients with PPP. Fungal DNA bands were detected in 68 samples, and fungi including Malassezia spp. were identified in 30 of 71 samples (42.3%). Malassezia restricta was the most frequently encountered fungus (14/71; 19.7%). However, bacterial DNA was not detected by the methods used. Furthermore, identical fungal DNA was not detected in the outer lid of the pustules, suggesting that the fungi detected within the pustule did not derive from contamination via the skin surface. In the present study, we demonstrated for the first time that certain pustules in patients with PPP contain fungal DNA fragments, especially those of Malassezia spp. Our findings provide new insights on the role of skin microbiota in the pathogenesis of PPP.

Inhibitory Effects of Diketopiperazines from Marine-Derived Streptomyces puniceus on the Isocitrate Lyase of Candida albicans.

The glyoxylate cycle is a sequence of anaplerotic reactions catalyzed by the key enzymes isocitrate lyase (ICL) and malate synthase, and plays an important role in the pathogenesis of microorganisms during infection. An icl-deletion mutant of Candida albicans exhibited reduced virulence in mice compared with the wild type. Five diketopiperazines, which are small and stable cyclic peptides, isolated from the marine-derived Streptomyces puniceus Act1085, were evaluated for their inhibitory effects on C. albicans ICL. The structures of these compounds were elucidated based on spectroscopic data and comparisons with previously reported data. Cyclo(L-Phe-L-Val) was identified as a potent ICL inhibitor, with a half maximal inhibitory concentration of 27 μg/mL. Based on the growth phenotype of the icl-deletion mutants and icl expression analyses, we demonstrated that cyclo(L-Phe-L-Val) inhibits the gene transcription of ICL in C. albicans under C2-carbon-utilizing conditions.

Automated Image Analysis for Determination of Antibody Titers Against Occupational Bacterial Antigens Using Indirect Immunofluorescence.

Employees who are exposed to high concentrations of microorganisms in bioaerosols frequently suffer from respiratory disorders. However, etiology and in particular potential roles of microorganisms in pathogenesis still need to be elucidated. Thus, determination of employees' antibody titers against specific occupational microbial antigens may lead to identification of potentially harmful species. Since indirect immunofluorescence (IIF) is easy to implement, we used this technique to analyze immunoreactions in human sera. In order to address disadvantageous inter-observer variations as well as the absence of quantifiable fluorescence data in conventional titer determination by eye, we specifically developed a software tool for automated image analysis. The 'Fluorolyzer' software is able to reliably quantify fluorescence intensities of antibody-bound bacterial cells on digital images. Subsequently, fluorescence values of single cells have been used to calculate non-discrete IgG titers. We tested this approach on multiple bacterial workplace isolates and determined titers in sera from 20 volunteers. Furthermore, we compared image-based results with the conventional manual readout and found significant correlation as well as statistically confirmed reproducibility. In conclusion, we successfully employed 'Fluorolyzer' for determination of titers against various bacterial species and demonstrated its applicability as a useful tool for reliable and efficient analysis of immune response toward occupational exposure to bioaerosols.

A study of the efficacy, safety and tolerance of cosmetic products for basic care and hygiene in a combined therapy of patients suffering from atopic dermatitis in the mild to moderate forms

The article is considering contemporary views on the role and significance of microorganisms in pathogenesis of atopic dermatitis. One can also find here efficiency analysis of cosmetics Emolium P «Triaktivnyj cream» and «Triaktivnaja bath emulsion» as treatments for low and middle severity atopic dermatitis, as well as research results of skin microbiota (before study initiation and on 14 day).

Two-dimensional Blue Native/SDS Gel Electrophoresis of Multiprotein Complexes from Helicobacter pylori

The study of protein interactions constitutes an important domain to understand the physiology and pathogenesis of microorganisms. The two-dimensional blue native/SDS-PAGE was initially reported to analyze membrane protein complexes. In this study, both cytoplasmic and membrane complexes of a bacterium, the strain J99 of the gastric pathogen Helicobacter pylori, were analyzed by this method. It was possible to identify 34 different proteins grouped in 13 multiprotein complexes, 11 from the cytoplasm and two from the membrane, either previously reported partially or totally in the literature. Besides complexes involved in H. pylori physiology, this method allowed the description of interactions involving known pathogenic factors such as (i) urease with the heat shock protein GroEL or with the putative ketol-acid reductoisomerase IlvC and (ii) the cag pathogenicity island CagA protein with the DNA gyrase GyrA as well as insight on the partners of TsaA, a peroxide reductase/stress-dependent molecular chaperone. The two-dimensional blue native/SDS-PAGE combined with mass spectrometry is a potential tool to study the differences in complexes isolated in various situations and also to study the interactions between bacterial and eucaryotic cell proteins.