Functional analysis to identify genes in wine yeast adaptation to low-temperature fermentation.

AIMS: To identify genes and proteins involved in adaptation to low-temperature fermentations in a commercial wine yeast. METHODS AND RESULTS: Nine proteins were identified as representing the most significant changes in proteomic maps during the first 24 h of fermentation at low (13°C) and standard temperature (25°C). These proteins were mainly involved in stress response and in glucose and nitrogen metabolism. Transcription analysis of the genes encoding most of these proteins within the same time frame of wine fermentation presented a good correlation with proteomic data. Knockout and overexpressing strains of some of these genes were constructed and tested to evaluate their ability to start the fermentation process. The strain overexpressing ILV5 improved its fermentation activity in the first hours of fermentation. This strain showed a quicker process of mitochondrial degeneration, an altered intracellular amino acid profile and laxer nitrogen catabolite repression regulation. CONCLUSIONS: The proteomic and transcriptomic analysis is useful to detect key molecular adaptation mechanisms of biotechnological interest for industrial processes. ILV5 gene seems to be important in wine yeast adaptation to low-temperature fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides information that might help improve the future performance of wine yeast, either by genetic modification or by adaptation during industrial production.

The role of GAP1 gene in the nitrogen metabolism of Saccharomyces cerevisiae during wine fermentation.

AIM: The aim of this study was to analyse the relevance of the general amino acid permease gene (GAP1) of the wine yeast Saccharomyces cerevisiae on nitrogen metabolism and fermentation performance. METHODS AND RESULTS: We constructed a gap1 mutant in a wine strain. We compared fermentation rate, biomass production and nitrogen consumption between the gap1 mutant and its parental strain during fermentations with different nitrogen concentrations. The fermentation capacity of the gap1 mutant strain was impaired in the nitrogen-limited and -excessive conditions. The nitrogen consumption rate between the wild strain and the mutant was different for some amino acids, especially those affected by nitrogen catabolite repression (NCR). The deletion of GAP1 gene also modified the gene expression of other permeases. CONCLUSIONS: The Gap1 permease seems to be important during wine fermentations with low and high nitrogen content, not only because of its amino acid transporter role but also because of its function as an amino acid sensor. SIGNIFICANCE AND IMPACT OF THE STUDY: A possible biotechnological advantage of a gap1 mutant is its scarce consumption of arginine, whose metabolism has been related to the production of the carcinogenic ethyl carbamate.

[457 inguinal and femoral hernioplasties with synthetic prosthetic materials]. / 457 de hernioplastii inghinale si femurale cu materiale protetice sintetice.

The authors retrospectively analyse 457 inguinal and femural hernioplasties with synthetic prosthesis materials, during a period of 10 years. There have been discussions going on about the prosthesis utilisation indications (advanced stages, complex inguinal hernia), type of prosthesis that has been used, the modalities of inserting a prosthesis and the surgical techniques employed. In 164 (34%) of the operations the mesh has been used as an reinforcement and 293 (64%) of the interventions were "tension-free" operations. The average reccurrence was approximately 1%, during a period ranging between 1 to 5 years.

Little-known mercury hazards.

Mercury contamination in three rarely studied areas of the hospital is discussed.