The yeast HSM3 gene acts in one of the mismatch repair pathways

Mutants with enhanced spontaneous mutability (hsm) to canavanine resistance were induced by N-methyl-N-nitrosourea in Saccharomyces cerevisiae. One bearing the hsm3-1 mutation was used for this study. This mutation does not increase sensitivity to the lethal action of different mutagens. The hsm3-1 mutation produces a mutator phenotype, enhancing the rates of spontaneous mutation to canavanine resistance and reversions of lys1-1 and his1-7. This mutation increases the rate of intragenic mitotic recombination at the ADE2 gene. The ability of the hsm3 mutant to correct DNA heteroduplex is reduced in comparison with the wild-type strain. All these phenotypes are similar to ones caused by pms1, mlhl and msh2 mutations. In contrast to these mutations, hsm3-1 increases the frequency of ade mutations induced by 6-HAP and UV light. Epistasis analysis of double mutants shows that the PMS1 and HSM3 genes control different mismatch repair systems. The HSM3 gene maps to the right arm of chromosome II, 25 cM distal to the HIS7 gene. Strains that bear a deleted open reading frame YBR272c have the genetic properties of the hsm3 mutant. The HSM3 product shows weak similarity to predicted products of the yeast MSH genes (homologs of the Escherichia coli mutS gene). The HSM3 gene may be a member of the yeast MutS homolog family, but its function in DNA metabolism differs from the functions of other yeast MutS homologs.     

The vitamin allowance of the pupils in a rural vocational and technical school and their prophylactic vitaminization]

The actual nutrition and providing with vitamins C and B1 was studied in boys aged 16-17 years, students of a rural trade school (Volsk of Saratov Province). Although the caloric value of their ration was high enough the content of animal proteins was only 42-48 g/day. The content of ascorbic acid in the ration comprised 48%, in the spring of 1987 it was 17%, and of 1988-29% of the recommended standard, vitamin B1 levels did not show seasonal differences. Vitamin C and B1 deficiencies in the spring were proved by their low excretion levels in urine, and by a low concentration of vitamin C and decreased activity of B1-dependent enzyme transketolase in the blood. Intake of "Undevitum" (1 dragee/day) during 4 months was conductive to the improvement of the student providing with vitamins.     

Transmission Spectra of Shallow-Layered Semiconductor‒Insulator Structure

The features of transmission spectra characterizing the layers of a shallow-layered semiconductor?insulator medium are investigated under the action of a magnetic field. In this case, n- and p-type semiconductors are analyzed. It is demonstrated that, at H₀ ≠ 0, the frequency gap, i.e., the zone eliminating wave transmission through a structure, is formed in the spectrum. In the absence of absorption near the lower zone edge (resonance frequency), the system of alternating narrow transmission and nontransmission zones concentrating with an approach to the resonance frequency is established to appear in the spectrum. It is revealed that oscillations arising near the frequency gap are smoothed with allowance for absorption in the structure.     

A Thermogravimetric Analysis Study of the Kuzbass Coals of Different Ranks

The coals of different ranks from the Kuznetsk Coal Basin were studied by thermogravimetric analysis in inert and oxidizing atmospheres. Correlations between thermal decomposition characteristics [maximum decomposition temperatures (T_max, °C), maximum rates of decomposition (Vmax, %/min), and sample weight losses in different temperature ranges (Δm, %)] and proximate analysis [yields of volatile substances (Vdaf, %)] and petrographic analysis [vitrinite reflectance (R_o)] data and NMR-spectroscopic data [aromaticity factor ( fa)] as the characteristics of the degree of maturity of the test coals were established.     

Wave properties of shallow-layer semiconductor–insulator medium in the presence of magnetic field

Expressions for effective permittivity of a periodic semiconductor–insulator structure with both n- and p-type semiconductor layers are derived in the approximation of shallow-layer medium. Dispersion relations are obtained for the TM wave that is controlled by external magnetic field with allowance for different propagation directions of the wave relative to the periodicity axis of the structure. Specific features of the transmission spectrum of wave are revealed for a layer of shallow-layer medium with finite thickness at several ratios of layer thicknesses in the period of structure.     

Development of a Sensitive Microarray Platform for the Ranking of Galectin Inhibitors: Identification of a Selective Galectin‐3 Inhibitor

Glycan microarrays are useful tools for lectin glycan profiling. The use of a glycan microarray based on evanescent‐field fluorescence detection was herein further extended to the screening of lectin inhibitors in competitive experiments. The efficacy of this approach was tested with 2/3′‐mono‐ and 2,3′‐diaromatic type II lactosamine derivatives and galectins as targets and was validated by comparison with fluorescence anisotropy proposed as an orthogonal protein interaction measurement technique. We showed that subtle differences in the architecture of the inhibitor could be sensed that pointed out the preference of galectin‐3 for 2′‐arylamido derivatives over ureas, thioureas, and amines and that of galectin‐7 for derivatives bearing an α substituent at the anomeric position of glucosamine. We eventually identified a diaromatic oxazoline as a highly specific inhibitor of galectin‐3 versus galectin‐1 and galectin‐7.