Biomedical subjects

D Gozalbo

Publications and source records attributed to D Gozalbo.

42 records · Page 3Linked to original sources

PubMed1987

Reversion of 7-methylguanosine 5'-phosphate inhibition of mRNA translation by polysomal and soluble factors isolated from Saccharomyces cerevisiae.

Protein fractions that overcome m7GMP inhibition of mRNA translation have been purified from the yeast S. cerevisiae. An active fraction isolated from polysomes contains two polypeptides of 220- and 190-kDa. The active fraction isolated from postribosomal supernatant contains a major polypeptide of 28-kDa and other species of 32-, 24-, 22- and 21-kDa, and sediments in sucrose gradients as a high molecular weight complex of about 200,000. This fraction restored yeast mRNA translation in reticulocyte lysates under conditions of yeast and globin mRNA competition; however, this effect was not observed with the 220- and 190-kDa polypeptides from polysomes. Nevertheless, translation of yeast mRNA was stimulated by a partially purified fraction containing a 28-kDa polypeptide from polysomes.

Fungal Proteins↗

PubMed1987

Differential translational efficiency of the mRNAs isolated from derepressed and glucose repressed Saccharomyces cerevisiae.

Carbon catabolite derepression induced changes in the pool of yeast mRNAs translatable in a protein-synthesizing reticulocyte system. Competition experiments with globin mRNA showed that the mRNA population obtained from derepressed cells possessed a higher translational efficiency than mRNA from repressed cells. The mRNAs that could account for the high translational efficiency of the derepressed mRNA were not detected in cells growing in glucose-rich medium. Analysis of protein synthesis in the presence of 7-methylguanosine 5'-phosphate indicated that the initiation factors recognizing the 5'-terminal structure of capped messengers interacted with lower affinity with the repressed than with some specific derepressed mRNAs.

Enzyme Repression↗

PubMed1983

Cell wall composition and protoplast regeneration in Candida albicans.

The transition of blastospores to the mycelial phase in Candida albicans was induced after the blastospores were kept at 4 degrees C for several hours and then transferred to a fresh medium prewarmed at 37 degrees C. Glucan was the most abundant polymer in the wall in the two morphogenetic forms but the amount of chitin was higher in the mycelial form than in blastospores. Efficient protoplasting required reducing agents and proteases together with beta-glucanases (zymolyase). Protein synthesis in regenerating protoplasts was initiated after about 30 min. Chitin synthetase, initially very low, was incorporated in important amounts into cell membranes mainly in a zymogenic state. After a few hours chitin was the most abundant polymer found in the aberrant wall of the regenerating protoplast.

Candida albicans↗

PubMed1982

Regulation of alpha-galactosidase synthesis in Saccharomyces cerevisiae and effect of cerulenin on the secretion of this enzyme.

Saccharomyces cerevisiae -136ts MEL10 (a thermosensitive mutant whose RNA synthesis is inhibited at 37 degrees C but is normal at 23 degrees C), when grown at 23 degrees C in the presence of galactose, melibiose or L-arabinose, these cells synthesize alpha-galactosidase mRNA. In the simultaneous presence of both galactose and glucose the transcription of alpha-galactosidase mRNA is blocked. Glucose also interferes with mRNA translation, but the degree of inhibition depends on concentration and time of addition of the hexose to induced cells. It has been found that the final concentration of alpha-galactosidase produced by induced cells when transferred at the non-permissive temperature (37 degrees C) is inversely proportional to the incubation time in glucose. Cerulenin inhibits lipid formation on growing yeasts, but protein synthesis and selective permeability are not affected. The antibiotic partially inhibits secretion of alpha-galactosidase with a parallel accumulation of this enzyme in membranous structures, specially at the level of the plasma membrane. Induction of alpha-galactosidase or cerulenin addition to growing cells, results in changes in the polypeptide composition of the plasma membrane.

Antifungal Agents↗

PubMedDate not supplied

Cloning of cDNAs coding for Candida albicans cell surface proteins.

Two cDNA libraries were constructed from mRNAs obtained from yeast cells and germ-tubes of Candida albicans in lambda gt11. Immunoscreening with polyclonal antibodies raised against cell wall components allowed the detection of 29 positive clones. Two of these clones were selected for their specific reactivity with antisera either from yeast (clone 11Y) or germ-tubes (clone 24M). cDNA fragments were isolated by the digestion of lambda DNA with EcoRI. Southern blot analysis with these fragments as probes demonstrated homology with C. albicans DNA, and by Northern analysis two mRNAs transcripts were detected with sizes of approximately 1.5 kb for 11Y and 1.1 kb for 24M. Both transcripts were present in yeast cells as well as in germ-tubes. The whole genes were isolated from a C. albicans genomic library in the YRp7 vector by hybridization with the cDNA probes. Monospecific antibodies were purified from polyclonal antisera by affinity for the fusion proteins. Western blot analysis with 11Y-specific antibodies revealed a cross-reactivity with material found in the yeast cell wall as well as in other subcellular fractions, whereas clone 24M codes for a 30 kDa protein detected mainly in the membrane fraction and in the SDS-solubilized material from mycelial cell walls. Sequencing of the cDNA molecules and restriction map of the cloned genes demonstrate that clone 11Y is an enolase previously characterized in C. albicans, whereas clone 24M does not show significant homology with any other cloned gene.

Amino Acid Sequence↗

PubMedDate not supplied

Cloning and characterization of a cDNA coding for Candida albicans polyubiquitin.

Immunoscreening of a Candida albicans cDNA library in the expression vector lambda gt11 with rabbit polyclonal antibodies against the 37 kDa cell surface laminin receptor of C albicans resulted in the isolation of a cDNA clone of 0.9 kb. Sequencing of this clone demonstrated a full length open reading frame encoding the polyubiquitin, which contains three tandem copies, head-to-tail spacerless repeats, of the 228 nucleotides coding for the 76 amino acids of the ubiquitin protein, which is identical to that of Saccharomyces cerevisiae. The third copy possesses an extra C-terminal amino acid which is distinct to that found in S. cerevisiae. Northern blot analysis revealed a single mRNA population of about 1 kb present in similar amounts in both yeast and mycelial cells. This indicates that the C. albicans polyubiquitin gene (UBI1) encodes a polyubiquitin precursor protein containing three ubiquitin repeats. Immunofluorescence and Western immunoblotting experiments with polyclonal antibodies against mammalian ubiquitin suggest the presence of ubiquitinated protein moieties in the wall of C. albicans cells.

Amino Acid Sequence↗