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Different Pathogens (different + pathogen)

Distribution by Scientific Domains
Medical Sciences50%
Life Sciences25%

Selected Abstracts

The Versatility of Helicobacter pylori CagA Effector Protein Functions: The Master Key Hypothesis

HELICOBACTER, Issue 3 2010
Steffen Backert
Abstract Several bacterial pathogens inject virulence proteins into host target cells that are substrates of eukaryotic tyrosine kinases. One of the key examples is the Helicobacter pylori CagA effector protein which is translocated by a type-IV secretion system. Injected CagA becomes tyrosine-phosphorylated on EPIYA sequence motifs by Src and Abl family kinases. CagA then binds to and activates/inactivates multiple signaling proteins in a phosphorylation-dependent and phosphorylation-independent manner. A recent proteomic screen systematically identified eukaryotic binding partners of the EPIYA phosphorylation sites of CagA and similar sites in other bacterial effectors by high-resolution mass spectrometry. Individual phosphorylation sites recruited a surprisingly high number of interaction partners suggesting that each phosphorylation site can interfere with many downstream pathways. We now count 20 reported cellular binding partners of CagA, which represents the highest quantitiy among all yet known virulence-associated effector proteins in the microbial world. This complexity generates a highly remarkable and puzzling scenario. In addition, the first crystal structure of CagA provided us with new information on the function of this important virulence determinant. Here we review the recent advances in characterizing the multiple binding signaling activities of CagA. Injected CagA can act as a ,master key' that evolved the ability to highjack multiple host cell signalling cascades, which include the induction of membrane dynamics, actin-cytoskeletal rearrangements and the disruption of cell-to-cell junctions as well as proliferative, pro-inflammatory and anti-apoptotic nuclear responses. The discovery that different pathogens use this common strategy to subvert host cell functions suggests that more examples will emerge soon. [source]

Natural killer cells: integrating diversity with function

IMMUNOLOGY, Issue 4 2009
Kuldeep Cheent
Summary The key role of natural killer cells in many aspects of the immune response is now being recognized. The last decade has seen an exponential increase in our understanding of the workings of these cells. Receptor diversity is crucial in allowing natural killer cells to respond effectively to a variety of different pathogens. This article reviews aspects of natural killer cell diversity that combine to generate populations of functional natural killer cells that exist within both the individual and throughout the population at large. [source]

Quantifying Phytophthora medicaginis in Susceptible and Resistant Alfalfa with a Real-Time Fluorescent PCR Assay

JOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2003
G. J. Vandemark
Abstract A real-time fluorescent PCR assay using a set of specific primers and a fluorochrome-labelled probe (TaqMan) was developed to quantify the amount of Phytophthora medicaginis DNA in alfalfa plants that were classified as either resistant or susceptible to the pathogen based on visual assessment of disease response. The assay clearly discriminated among three standard check alfalfa populations with different levels of resistance based on the analysis of DNA extracted from the roots of bulked plant samples. In two independent experiments, the Spearman rank correlation between pathogen DNA content and the number of susceptible plants in a bulked sample was greater than 0.89 and highly significant (P<0.0001). Significantly less pathogen DNA was detected in bulked samples of a highly resistant check population than in bulked samples from more susceptible check populations. Analysis of individual plants indicated that significantly less pathogen DNA was detected in resistant plants than in susceptible plants. Applications of the assay are considered for breeding programs and the study of microbial population dynamics in plants simultaneously infected with different pathogens. [source]

First-generation SNP/InDel markers tagging loci for pathogen resistance in the potato genome

PLANT BIOTECHNOLOGY JOURNAL, Issue 6 2003
Andreas M. Rickert
Summary A panel of 17 tetraploid and 11 diploid potato genotypes was screened by comparative sequence analysis of polymerase chain reaction (PCR) products for single nucleotide polymorphisms (SNPs) and insertion-deletion polymorphisms (InDels), in regions of the potato genome where genes for qualitative and/or quantitative resistance to different pathogens have been localized. Most SNP and InDel markers were derived from bacterial artificial chromosome (BAC) insertions that contain sequences similar to the family of plant genes for pathogen resistance having nucleotide-binding-site and leucine-rich-repeat domains (NBS-LRR-type genes). Forty-four such NBS-LRR-type genes containing BAC-insertions were mapped to 14 loci, which tag most known resistance quantitative trait loci (QTL) in potato. Resistance QTL not linked to known resistance-gene-like (RGL) sequences were tagged with other markers. In total, 78 genomic DNA fragments with an overall length of 31 kb were comparatively sequenced in the panel of 28 genotypes. 1498 SNPs and 127 InDels were identified, which corresponded, on average, to one SNP every 21 base pairs and one InDel every 243 base pairs. The nucleotide diversity of the tetraploid genotypes (, = 0.72 × 10,3) was lower when compared with diploid genotypes (, = 2.31 × 10,3). RGL sequences showed higher nucleotide diversity when compared with other sequences, suggesting evolution by divergent selection. Information on sequences, sequence similarities, SNPs and InDels is provided in a database that can be queried via the Internet. [source]

Silver-Loaded Cotton/Polyester Fabric Modified by Dielectric Barrier Discharge Treatment

PLASMA PROCESSES AND POLYMERS, Issue 1 2009
Mirjana Kosti
Abstract The preparation of antimicrobial silver-loaded cotton/polyester fabrics has been carried out by DBD surface activation followed by silver sorption from aqueous silver nitrate solution. A series of DBD fabric treatments was performed in order to determine the most suitable experimental conditions for the fabric surface activation. The capillarity, silver ion uptake, and copper number were used to assess the surface changes on the fabrics. An effective process has been developed to obtain antimicrobial silver-loaded Co/PES fabrics. The antimicrobial activity of the silver-loaded fabrics against different pathogens was evaluated in vitro. The quantity of bonded silver ions is enough to develop desirable antimicrobial activity in the Co/PES fabrics. [source]

Proteome characterization of human T helper 1 and 2 cells

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 1 2004
Kirsi Rautajoki
Abstract T helper (Th) cells can be polarized into two different main subtypes, Th1 and Th2 cells. Their activation is linked to the eradication of different pathogens and to dissimilar immunological dysfunctions, which implies differences also in their protein expression patterns. To identify these differences, CD4+ T cells were isolated from human cord blood, polarized in vitro to Th1 and Th2 and activated via CD3 and CD28. Cells were lysed, soluble proteins were separated with two-dimensional electrophoresis and differing protein spots were identified with peptide mass fingerprinting. The expression of 14 proteins differed in Th1 and Th2 cells after both 7 and 14 days of polarization. Twelve of the proteins could be identified, most of which are new in this context. Two proteins were differentially modified in the two cell types. Especially, N -terminal acetylation of cyclophilin A was stronger in Th1 than in Th2 cells. To compare the RNA and the protein levels of the identified genes, mRNA expression was measured with Affymetrix oligonucleotide microarrays (HG-U133A). The mRNA and protein expression level correlated only in six cases out of eleven, which highlights the complementary roles that proteomics and transcriptomics have in the elucidation of biological phenomena. [source]

In vitro activity of dermaseptin S1 derivatives against genital pathogens

APMIS, Issue 9 2010
DIANELLA SAVOIA
Savoia D, Donalisio M, Civra A, Salvadori S, Guerrini R. In vitro activity of dermaseptin S1 derivatives against genital pathogens. APMIS 2010; 118: 674,80. The aim of this study was to evaluate the biological activity of nine dermaseptin-S1 (DRS-S1) derivatives (synthesized by solid-phase methods and purified) against different pathogens causing genital infections (Trichomonas vaginalis, Herpes simplex virus, Papillomavirus). The in vitro activity on T. vaginalis was determined by counting the protozoon in a hemocytometer after vital staining with trypan blue; antiviral activity of the compounds was tested on monolayers of Vero cells for Herpes simplex virus-1 (GFP) and on 293TT cells for human papillomavirus (HPV-16) pseudovirions (GFP). The cytotoxicity of the derivatives was assessed by evaluating both the hemolytic activity and the effect on Vero and 293TT cells. The DRS-S1 longer peptides demonstrated a superior activity on T. vaginalis but also a certain cytopathic effect. The compounds with 29 amino acids exhibited activity against the two viruses tested at concentrations not toxic to cells. The results obtained show that some of the synthetic peptides assessed have inhibitory activity against the pathogens tested, indicating a potential for the development of new molecules for use as topical microbicides to prevent the sexual transmission of microorganisms. [source]

Epidemiology, clinical presentation and diagnosis of onychomycosis

BRITISH JOURNAL OF DERMATOLOGY, Issue 2003
J. Faergemann
Summary Onychomycosis is a common nail disease, responsible for up to 50% of diseases of the nail. The distribution of different pathogens is not uniform; it depends on various factors such as climate, geography and migration. However, studies have revealed that two dermatophytes, Trichophyton rubrum and Trichophyton mentagrophytes, account for more than 90% of onychomycoses. Onychomycosis can be divided into four major clinical presentations: distal subungal (the most common form of the disease), proximal subungal (the most common form found in patients with human immunodeficiency virus infection), and superficial and total dystrophic onychomycosis. Onychomycosis is a multifactorial disease. Age has a very important effect on the occurrence of onychomycosis, with a correlation between increasing age and infection. Genetics has also been identified as a factor governing the epidemiology of onychomycosis; T. rubrum infection shows a familial pattern of autosomal dominant inheritance. Disease and lifestyle may also play a role in the epidemiology of fungal nail infections. Studies have shown that diabetes, acquired immunodeficiency syndrome and peripheral arterial disease may be independent predictors of onychomycosis. Because of the multifactorial nature of the epidemiology, accurate diagnosis, pertinent treatment and patient education must be paramount when treating the disease. [source]