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In yeast, external signals such as high osmolarity or oxidant conditions activate the high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) cascade pathway, which consists of two upstream branches, i.e. Sho1p and Sln1p and common downstream elements, including the Pbs2p MAPK kinase and the Hog1p MAPK. We recently showed that the Candida lusitaniae SLN1 gene, potentially encoding a histidine kinase receptor, is crucial for oxidative stress adaptation when the fungus grows as budding yeast and during the early steps of pseudohyphal development. In the current study, we characterized the SHO1 gene of this opportunistic fungus. Complete loss of SHO1 function causes profound defects in pseudohyphal differentiation, especially in high osmolarity and oxidative stress conditions, suggesting a crucial role of SHO1 in the pseudohyphae morphogenetic transitions. Moreover, when grown as budding yeast, the sho1Delta mutant revealed a sensitivity to compounds that interfere with the cell wall assembly, pointing to a potential role of Sho1p in cell wall biogenesis. However, the sho1Delta mutant does not display evident cell-wall architecture modifications, such as aggregation phenotypes. Although not hypersusceptible to antifungals of clinical relevance, the sho1Delta mutants are susceptible to the filamentous fungi-specific antifungals dicarboximides and phenylpyrroles. Finally, our findings highlight some significant phenotypic differences when the C. lusitaniae sho1Delta mutant is compared with the corresponding mutants described in Saccharomyces cerevisiae, Candida albicans and Aspergillus fumigatus., ((c) 2008 John Wiley & Sons, Ltd.)

The nucleotide sequence of the URA3 gene encoding orotidine-5'-phosphate decarboxylase (OMP DCase) of the human opportunistic pathogen yeast Candida lusitaniae was determined by degenerate PCR and chromosome walking. Deduced amino acid sequence showed strong homologies (59-85% identity) with OMP DCases of different Saccharomycetales and allowed identification of the known conserved domains. Very close upstream from the URA3 gene, the 3'-end of a gene encoding a Gea2-like protein was identified. A non-revertible C. lusitaniae ura3 mutant was selected on the basis of 5-fluoroorotic acid resistance. The mutation was a single point mutation resulting in the amino acid substitution D95V in a highly conserved domain, and in a concomitant EcoRV restriction site polymorphism. The mutant strain was successfully transformed to prototrophy following electroporation with the URA3 gene cloned in an integrative vector, with frequencies of 100-200 transformants per micro g of DNA. Southern blot analysis revealed that almost all transformants were derived from homologous recombination events at the resident locus. The GeneBank Accession No. for C. lusitaniae URA3 gene is AF450297., (Copyright 2003 John Wiley & Sons, Ltd.)

An essential element of implicit solvent models, such as the generalized Born method, is a knowledge of the volume associated with the individual atoms of the solute. Two approaches for determining atomic volumes for the generalized Born model are described; one is based on Voronoi polyhedra and the other, on minimizing the fluctuations in the overall volume of the solute. Volumes to be used with various parameter sets for protein and nucleic acids in the CHARMM force field are determined from a large set of known structures. The volumes resulting from the two different approaches are compared with respect to various parameters, including the size and solvent accessibility of the structures from which they are determined. The question of whether to include hydrogens in the atomic representation of the solute volume is examined. Copyright 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1857-1879, 2001

Magnetic resonance experiments require the main magnetic field, B(0), to remain very stable. Several external sources, such as moving ferromagnetic objects and/or changing electromagnetic fields, can significantly change the value of B(0) over time. This work describes an apparent displacement along the phase-encoding axis caused by a variation in B(0). This artifact was observed in fMRI images acquired with EPI. The effect was characterized and tested using an immobile phantom. The image displacement motion along the phase-encoding axis closely followed the changes in B(0). The phase of the central line in the Fourier space was successfully used to correct this artifact. Fluctuations in B(0) may result in artifacts that mimic subject head motion, and must be appropriately corrected. Magn Reson Med 46:198-201, 2001., (Copyright 2001 Wiley-Liss, Inc.)

Identification of a case of acute salicylate intoxication using 300 MHz 1H NMR spectroscopy of a urine sample is reported. It has been achieved by using a combination of a one-dimensional experiment with water presaturation and a two-dimensional homonuclear J-resolved experiment. By these means, lysine and the three major metabolites of acetylsalicylic acid have been assigned in the crude urine. The results are compared with those obtained at 600 MHz and with classical biochemical methods. The use of this method for routine diagnosis in biological analysis is discussed.