A novel approach to isolation and functional characterization of genomic DNA from the methylotrophic yeast Hansenula polymorpha

A novel approach to isolation and functional characterization of the Hansenula polymorpha genes basing on the use of two strains of different origin is described. One of these strains is better suited for the isolation of genomic DNA fragments, while the other is preferable for their functional analysis. Thirty three genomic sequences governing expression of a reporter protein have been isolated. Analysis of the sequence encoding a homolog of the Saccharomyces cerevisiae cofilin revealed two introns. Another isolated DNA fragment encoded a homolog of the S. cerevisiae V ps10p. Disruption of the corresponding gene resulted in secretion of a vacuolar protein, carboxypeptidase Y, into the culture medium.     

Molecular evolutionary dynamics of cytochrome b in strepsirrhine primates: the phylogenetic significance of third-position transversions

DNA sequences of the complete cytochrome b gene are shown to contain robust phylogenetic signal for the strepsirrhine primates (i.e., lemurs and lorises). The phylogeny derived from these data conforms to other molecular studies of strepsirrhine relationships despite the fact that uncorrected nucleotide distances are high for nearly all intrastrepsirrhine comparisons, with most in the 15%-20% range. Cytochrome b sequences support the hypothesis that Malagasy lemuriforms and Afro-Asian lorisiforms each comprise clades that share a sister- group relationship. A study (Adkins and Honeycutt 1994) of the cytochrome c oxidase subunit II (COII) gene placed one Malagasy primate (Daubentonia) at the base of the strepsirrhine clade, thereby suggesting a diphyletic Lemuriformes. The reanalysis of COII third- position transversions, either alone or in combination with cytochrome b third-position transversions, however, yields a tree that is congruent with phylogenetic hypotheses derived from cytochrome b and other genetic data sets.      

Synthetic peptides -- analogs of biologically active fragment of the differentiation factor from HL-60 cells show radioprotective and adaptogenic activities

It was shown that the addition of synthetic six-membered peptide (HLDF-6) and its Tyr-analog (HLDF-Y) to cultural medium significantly increased the survival of cells HL-60, treated by cold shock. The prophylactic administration of HDLF-Y (1 mg/kg, 4 hours prior to applied actions) decreased the response of hypothalamushypophysis-adrenal glands system and sympathicoadrenal system of rat males on supercooling and also increased the resistance of mouse males to supercooling and X-irradiation. In the experiences with females HDLF-Y did not show the similar biological activity.     

A computer method for assessing the average rate of movement of Paramecium caudatum by a cross-sectional light beam

The possibility of using the motility of Paramecium caudatum for computer biotesting of toxic substances was studied. The method is based on measuring the number and duration of impulses that arise when protozoa chaotically moving in a layer 0.5 mm thick cross a red light beam (1 mm in diameter). It was found that, in the presence of Cu2+ ions and menadione bisulfite, a compound having prooxidant properties, the number of impulses decreased with a concurrent increase in the duration of impulses. The high correlation between the number of impulses and the reciprocal of impulse duration indicates that the motility of paramecium by the action of Cu2+ ions and menadione slow down, and even an immobilization of some of them occurs. The mean swimming velocity of protozoa was reduced by half within 20 min by the action of Cu2+ at a concentration of 90 microM (6 mg/l of Cu2+ ions) and within 80 min by the action of menadione bisulfite at a concentration of 50 microM. It was shown that the slowing down of motility, which indicates the presence of a toxicant in the medium, is a faster physiological reaction than cell death.     

Clock synchronization in various modes of regulation

In this study, which is dedicated to the participants of I. M. Gelfand's scientific seminar, the regulation mechanisms for the clock synchronization in an isolated biological community are analyzed. A comparison has been carried out of the time consumed and the work done taking into account the specific error value for three modes of regulation: centralized regulation, centralized hierarchy regulation, and self-organization based on paired interaction. The results of the study may have different biophysical applications.     

Structural changes in proteins of the bacteriophage T4 basal plate resulting from the attachment of long fibrils

The effect of the attachment of long tail fibers on the structure of proteins of the bacteriophage T4 baseplate was studied by digital processing of electron microscopic images. The attachment of the long fibers was found to result in dramatical changes of the proteins of the baseplate plag, while the wedges, to which the long fibers are attached, undergo only slight changes. We studied the baseplates with one to six attached fibers and found that the attachment of one fiber resulted in the change of the entire baseplate, although the wedge located in the vicinity of the fiber attachment changed to a greater extent. Only after the attachment of three and more fibers the changes of the same kind occurred through the entire baseplate.     

Correlation between the level of fluorescent aging pigments in homogenates of the rat cerebral cortex and the constant brain potential during late ontogenesis

A strong correlation (R = 0.5 + 0.88) was found between the constant potential level of the rat brain and the content of aging pigments in the brain cortex homogenates. The latter was measured by synchronous scanning of luminescence in each hemisphere separately.