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Intrinsic Sensitivity (intrinsic + sensitivity)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Investigating the role of ABC transporters in multifungicide insensitivity in Phytophthora infestans

MOLECULAR PLANT PATHOLOGY, Issue 1 2006
HOWARD S. JUDELSON
SUMMARY Isolates of the oomycete Phytophthora infestans exhibit a wide range of intrinsic sensitivities to fungicides, which potentially influences the application rates of chemicals needed to control potato late blight. To help understand what determines such levels of sensitivity, a genetic approach was employed which followed the segregation of sensitivities to structurally diverse fungicides such as metalaxyl and trifloxystrobin. Progeny exhibited broad distributions of sensitivity phenotypes, consistent with the behaviour of a quantitative trait. Measurements of the inhibition of strains by seven fungicides revealed that basal sensitivities to metalaxyl and trifloxystrobin, and to cymoxanil and dimethomorph, correlated at the 95% confidence level. These compounds have distinct modes of action, suggesting the involvement of a multifungicide efflux phenomenon mediated by ABC transporters. To determine whether such proteins contribute to variation in sensitivity, 41 full transporters and 13 half transporters were identified from P. infestans and their mRNA levels compared in strains exhibiting higher or lower sensitivities to fungicides. No correlation was observed between the expression of any ABC transporter and fungicide sensitivity. Other genes, or variation in the activities of the transporters, may therefore explain the differences between strains. Five ABC transporters were induced by several fungicides in strains with both higher and lower sensitivities to fungicides, which probably reflects the existence of a network for protecting against natural and artificial toxins. [source]

Unequivocal morphological diagnosis of fungi in morphologically abnormal nails

HISTOPATHOLOGY, Issue 7 2006
A Cabral
Aims :,To analyse the prevalence of fungi in abnormal nails by morphological diagnosis. Prevalence studies of onychomycoses in temperate climate zones have yielded widely varying rates, possibly reflecting the confounding effects of referral bias, sampling specificity and intrinsic sensitivity of the diagnostic techniques employed. Methods and results :,The method employed to identify fungi in nails entailed primary fixation using a non-formaldehyde-based coagulative fixative (BoonFix®; Finetec, Japan) and microwave-enhanced processing to histology, followed by staining the paraffin sections with periodic acid,Schiff, using haematoxylin as a routine counterstain. The results of 990 nail samples were tabled for statistical analysis related to gender, patient age and diabetes mellitus status. In four of the 990 (< 1%) analysed cases the diagnosis was found to be equivocal using the method employed. These cases were jointly reviewed for definitive diagnosis. The overall prevalence of invasive hyphal structures was found to be 606/990 (, 61%). The relative risk for fungal infection in morphologically abnormal nails was found to be higher for persons <,20 years old or diabetic patients aged ,,71 years. Conclusions :,The 61% positivity rate for fungi found justifies systematic direct submission of samples from abnormal nails for histological confirmation in order to avoid unwarranted treatment. [source]

Solution structure determination of oligoureas using methylene spin state selective NMR at 13C natural abundance

MAGNETIC RESONANCE IN CHEMISTRY, Issue 10 2008
Gilles Guichard
Abstract Ability of N,N,-linked oligoureas containing proteinogenic side chains to adopt a stable helix conformation in solution has been described recently. NMR as well as circular dichroism (CD) spectroscopies were employed to gain insight into their specific fold. It is herein proposed to extend the structural information available on these peptidomimetics by an advantageous use of a methylene spin state selective NMR experiment. Homodecoupling provided by the pulse scheme made it possible to readily measure conformation-dependent 3JHH constants that are difficult if not impossible to obtain with standard NMR experiments. Adding those couplings to the NMR restraints improved the quality of the structure calculations significantly, as judged by a ca 30% decrease of the root mean square deviation (RMSD) obtained over an ensemble of 20 structures. Moreover, accurate determination of individual 1JCH couplings within each methylene group revealed uniform values throughout the oligourea sequence, with 1JCH systematically slightly larger for the pro-S hydrogen than for the pro-R. As shown in this study, the methylene spin state selective NMR experiment displays a good intrinsic sensitivity and could therefore provide valuable structural information at 13C natural abundance for peptidomimetic molecules and foldamers bearing diastereotopic methylene protons. Copyright © 2008 John Wiley & Sons, Ltd. [source]

The dual role of Fas-ligand as an injury effector and defense strategy in diabetes and islet transplantation,

BIOESSAYS, Issue 2 2006
Michal Pearl-Yafe
The exact process that leads to the eruption of autoimmune reactions against , cells and the evolution of diabetes is not fully understood. Macrophages and T cells may launch an initial immune reaction against the pancreatic islets of Langerhans, provoking inflammation and destructive insulitis. The information on the molecular mechanisms of the emergence of , cell injury is controversial and points to possibly important roles for the perforin,granzyme, Fas,Fas-ligand (FasL) and tumor-necrosis-factor-mediated apoptotic pathways. FasL has several unique features that make it a potentially ideal immunomodulatory tool. Most important, FasL is selectively toxic to cytotoxic T cells and less harmful to regulatory T cells. This review discusses the intrinsic sensitivity of , cells to FasL-mediated apoptosis, the conditions that underlie this , cell sensitivity, and the feasibility of using FasL to arrest autoimmunity and prevent islet allograft rejection. In both the autoimmune and transplant settings, it is imperative to progress from the administration of nonspecific immunosuppressive therapy to the concept of ,-cell-specific immunomodulation. FasL evolves as a prime candidate for antigen-specific immunomodulation. BioEssays 28: 211,222, 2006. © 2006 Wiley periodicals, Inc. [source]