Cryptic heterokaryons in strains of Saccharomyces cerevisiae. Conditions for detecting a cryptic nucleus

A phenomenon discovered earlier, cryptic heterokaryosis in Saccharomyces yeast, has been further investigated. A phenotypically silent nucleus in a yeast cell may resume its expression after fusion with another parental cell. The resulting hybrid is capable of sporulation. By the growth of a cytoductant with an expressing nucleus from one parent and a silent nucleus from the other parent on suitable selective media, the silent nucleus can be activated. The presence of deletion or insertion mutations in several genes in YPH strains allows nuclei of the YPH type to be traced not only genetically but also by blotting.     

P53-status of cells from patients with progeria and ataxia-telangiectasia exposed to ionizing irradiation

P53 protein expression and stabilization in cell strains derived from patients suffering from progeria and ataxia-telangiectasia following gamma-irradiation have been described. A similar pattern of P53-status in healthy donor and progeria patient cells was shown using immunofluorescent cell staining. In ataxia-telangiectasia cells (strain AT2SP) the P53 protein was not detected by the same method. These data well compare with literary evidence on a disturbed P53-status at ataxia-telangiectasia.     

COMMON AND SPECIFIC EFFECTS OF FINE FRAGRANCES ON THE MOOD OF WOMEN

The effect of three pleasant fine women's fragrances on the mood of women was assessed. The three fragrances had similar hedonic values but different sensory characteristics. The fragrances elicited nonspecific effects on mood. All three fragrances’ impact on mood was influenced by initial mood and lasted up to three hours, i.e., as long as the scent was still noticeable. Trends revealed that all three fragrances decreased negative affect and increased vigor. Also, independent of their hedonic value, the three fragrances elicited specific mood patterns. With the “woody citrus coniferous” scent, respondents experienced higher hostility and tension. The “floral chypre citrus” fragrance decreased anger and confusion. The “floral woody” scent had the lowest Total Mood Disturbance score and lowered depression, tension and confusion.     

Psychophysiological monitoring under conditions of real and simulated microgravity.

Dynamics of indices characterizing the process of adaptation of operators to complicated conditions of vital activity was studied with psychophysiological monitoring. This technique is based on the complex analysis of subjective and objective estimations of the current psychoemotional state and physiological and biochemical indices. We analyzed the data obtained during the examination of three healthy volunteers, who participated in the HUBES experiment (135-day isolation in the ground-based model of the orbital station "Mir"), and during a biorhythmological study conducted by six Russian cosmonauts of the main expeditions on the station "Mir." It was shown that psychophysiological monitoring is an informative method for studying different parameters of the operator's state and regulatory processes, the dynamics of biological rhythms, and individual characteristics of adaptation. By means of the analysis of a population of the variation in the characteristics of the parameters under study the experimental period of isolation was divided into three stages. The first and third stages were characterized by a relatively high variability, which was minimized at the second stage. The phasic character of the adaptation processes with a phase duration of about 60 days was revealed and a correlation was shown between the dynamics of parameters obtained by means of psychophysiological monitoring and specific features of the system regulation in different phases of the space flight and its simulation. It is suggested that the phases of the minimal variability of the studied characteristics are related to the periods of the minimal reliability of an operator's work. [Translated from Fiziologiya Cheloveka, vol. 25, no. 5, 1999 Sep-Oct, p. 86-91]     

DNA-polycation complexes: effect of polycation structure on physico-chemical and biological properties

The purpose of the study was to investigate the influence of cationic polymer structure on the formation of DNA-polycation complexes and their transfection activity. Primary, tertiary, and quaternary polyamines with molecular masses ranging from 8000 to 200,000 were investigated. DNA-cationic polymer interaction was characterized by low gradient viscometry, dynamic light scattering, circular dichroism, UV spectrometry, flow birefringence, DNA electrophoresis, and electron microscopy. Transfection activity of the complexes was evaluated by the expression of reporter gene (beta-galactosidase) and using synthetic FITC-labelled oligonucleotides. Complex formation was found to be dependent on the structure and molecular weight of the polymer and the ionic strength of the solution. Secondary DNA structure in complexes was not disrupted, and DNA was protected from protonation. Cell lines of different origin were used for testing of transfection activity of the complexes. The sensitivity of the cells to transfection was established to be highly dependent on the cell line. DNA-polycation complexes are non-toxic according to MTT. Polyallylamine, and polydimethylaminoethylmethacrylate were found to be the most promising polycations for gene delivery. Transfection efficacy of their complexes with DNA to T-98G cells reaches up to 90-100%. It was found that optimal molecular mass of polydimethylaminoethylmethacrylate is in the range of 8000-50,000 Da.     

Ginsenoside production,growth and cytogenetic characteristics of sustained <Emphasis Type="Italic">Panax japonicus</Emphasis> var. <Emphasis Type="Italic">Repens</Emphasis> cell suspension culture

Cytophysiological and cytogenetic characteristics of cell suspension culture of Panax japonicus var. repens were studied in relation to the accumulation of ginsenosides (GSs). The minimal time of cell number doubling was 1.3 ± 0.1 d and cell number increased 7 to 8-fold during growth cycle. The cell culture can be considered as aneuploid with about tetraploid (46–60 chromosomes) modal class. Upon long-term cultivation, the total content of GSs considerably increased and maximal concentration of GSs was 2.2 %(d.m.). The ratio of seven major GSs only slightly altered both over each and different subcultures. The overall amount of GSs of Rg-group significantly exceeded that of Rb-group. Cell volume and the number of large cellular aggregates with the higher proportion (by 20 %) of parenchymal cells increased late in the subculture. In this time the population contained about 20 % of the cells with doubled amount of nuclear DNA and accompanied with elevation in the GS content. These data prompted us to suggest that biosynthesis of GSs has a link with cell differentiation. In memory of Prof. R.G. Butenko     

A highly branched storage polyglucan in the thermoacidophilic red microalga Galdieria maxima cells

The thermoacidophilic red alga Galdieria maxima is capable of heterotrophic growth. The content of carbohydrates in H. maxima grown heterotrophically increases by a factor of 4, reaching as much as 60% of cell dry weight. The increase in the level of carbohydrates in cells is due to accumulation of a storage alpha-glycan. According to a specific cleavage to glucose catalyzed by amyloglucosidase and the high positive specific optical rotation characteristic of polyglucans, this polysaccharide can be classified as a floridean starch. The data of 1H NMR spectroscopy and the results of methylation showed that the average length of the unbranched regions of the polysaccharide molecule is six to seven glucose residues. The degree of branching of the starch molecule of G. maxima is greater than that of storage polysaccharides of other red algae, glycogens of yeast, and phytoglycogens of cyanobacteria.