Transcriptional regulators of seven yeast species: comparative genome analysis. Review.

The regulation of gene transcription allows yeast cells to respond properly to changing environmental conditions. Several protein complexes take part in this process. They involve RNA polymerase complexes, chromatin remodeling complexes, mediators, general transcription factors and specific transcriptional regulators. Using Saccharomyces cerevisiae as reference, the genomes of six species (Ashbya gossypii, Kluyveromyces lactis, K. waltii, Candida albicans, C. glabrata and Schizosaccharomyces pombe) that are human pathogens or important for the food industry were analyzed for their complement of genes encoding the homologous transcriptional regulators. The number of orthologs identified in a given species correlated with its phylogenetic distance from S. cerevisiae. Many duplicated genes encoding transcriptional regulators in S. cerevisiae and C. glabrata were reduced to one copy in species diverged before the ancestral whole genome duplication. Some transcriptional regulators appear to be specific for S. cerevisiae and probably reflect the physiological differences among species. Phylogenetic analysis and conserved gene order relationships indicate that a similar set of gene families involved in the control of multidrug resistance and oxidative stress response already existed in the common ancestor of the compared fungal species.

[Measured and predicted oxygen uptake in highly qualified athletes]. / Rzeczywisty i przewidywany pobór tlenu u wysoko kwalifikowanych sportowców.

UNLABELLED: Applied methods of maximal oxygen uptake (VO2max) estimation can be generally divided into direct ones, based on oxygen uptake measured at maximal load level, and indirect ones, connected with submaximal load levels. It has been observed that maximal oxygen uptake in adults and people well adapted to physical exercise undergoes only small changes, whereas reaction of the circulatory system at submaximal load is variable and may influence the results achieved by indirect methods of oxygen uptake estimation, based on referring heart rate to the load level. Maximal oxygen uptake values measured directly were compared with foreseen values using two indirect methods: Astrand-Rhyming nomogram and von Döbeln formula. Studies were performed in highly qualified oarsmen, cyclists and swimmers (Tb. 1), representatives of sport disciplines significantly different as far as the type of physical exercise is concerned, which may cause different developing adaptation mechanisms. In groups we carried out spiroergometric test which can provide reports of the patient's heart rates (HR) and direct measurements of oxygen uptake (VO2) in steady state at different load levels. At the maximal exercise load we measured VO2max and HRmax. HR values were used to estimate VO2max by indirect methods. Following questions have been asked: 1. What is the convergence between VO2max values measured directly and those estimated by Astrand-Rhyming and von Döbeln methods? 2. What is the diagnostic usefulness of the indirect VO2max estimation in highly qualified groups of sportsmen? At the end of the test VO2max values were in oarsmen 5.139 +/- 0.06 1/min, in cyclists 5.085 +/- 0.05 l/min, in swimmers 4.689 +/- 0.01 l/min. Average VO2max values in indirect Astrand-Rhyming method (Tab. 2) in all groups estimated using HR values taken at lower exercise loads (100 W, 150 W, 200 W), were statistically lower than those measured directly (P < 0.01, P < 0.001, while values taken at 250 W were situated close to. VO2max estimated directly and indirectly being correlated in oarsmen at 200 W (0.316 < r < 0.411), in cyclists at 150 W and 200 W (0.343 < r < 0.599), and in swimmers at 150 W and 200 W--only for A3-VO2max (r = 0.3 and r = 0.37). Maximal oxygen uptake estimated by using von Döbeln formula (Tab. 3) was in all cases significantly lower (P < 0.001) then measured (values ranged from 72% to 79% VO2max of those measured directly). Significant correlation was observed at all applied exercise loads in oarsmen and cyclists (0.284 < r < 0.597) and in swimmers only at 200 W and 250 W (0.245 < r < 0.370). CONCLUSIONS: 1. Indirect VO2max estimation based on load level and heart rate in Astrand-Rhyming method gives results compatible with direct measurements of oxygen uptake only using significant loads, adequate to physical efficiency in investigated people (HR near 160 beats per min., 70-80% Hrmax; oxygen uptake near 80% VO2max. 2. Estimating VO2max by Astrand-Rhyming method one should apply the correction regarding maximal heart rate, in case of unknown maximal heart rate the age-factor should be applied, which is of lower significance. 3. In highly qualified sportsmen one should't estimate VO2max using von Döbeln method; values achieved are significantly lower than those estimated in direct oxygen uptake measurements.

Kinetics of ascorbate depletion in guinea pigs after long-term high vitamin C intake.

Half-lives of ascorbate depletion in 9 organs proved the same in guinea pigs receiving minimum maintenance dose of ascorbic acid (0.5 mg/animal/day) during 15 weeks of the pre-experimental period, as in those on very high doses (0.5% ascorbic acid in diet = 300 mg/kg body weight/day). The survival on the ascorbate-free diet proved longer in guinea pigs receiving high vitamin C doses (0.5% in diet) for 7 months previously, than in those with a tenfold lower vitamin C supply (0.05% in diet). Permanently high vitamin C intake does not induce induce systemic conditioning in adult guinea pigs.