Lipase-catalyzed transamidation of non-activated amides in organic solvent

A novel biocatalytic reaction of transamidation of non-activated amides with amines is reported. Among 45 different lipolytic and proteolytic enzymes tested, only the lipase from Candida antarcticawas able to catalyze this reaction. The reaction proceeded with up to ca. 80% conversion in anhydrous methyl tert-butyl ether and worked with both N-substituted and unsubstituted amides. The biocatalytic transamidation is an equilibrium process and, therefore, higher conversions to the desired amide were achieved by using increased concentrations of the amine nucleophile.     

Cell-by-cell flow cytometric analysis of chromosomes

The authors discuss various aspects of a recently developed method permitting a detailed flow cytometric analysis of the individual cell karyotypes such as instrumentation, histochemistry, data proceeding algorithms. Possible drawbacks of the method and the ways of their overcoming are considered. Results of analysis of the Chinese hamster cells are presented that illustrate the possibilities of the method, including the metaphase chromosome distribution according to their fluorescence intensity, the analysed cell distribution according to their chromosomes number, the table in which the individual cell karyotypes are distributed according to their fluorescence. The results obtained show that the developed method may be successfully used for investigating chromosomal iNstability and heterogeneity of the mammalian cells.     

Paramagnetic form of ribonucleotide reductase in human tissues

The paramagnetic form of ribonucleotide reductase was detected by ESR method in human cervix tissues, especially in tumor ones. The magnetic relaxation rate was proved to be slower for this form than for that in normal animal tissues having a high level of proliferative activity or in Ehrlich tumor cells studied before.     

Informosomes and translation activity of mRNA in eukaryotic cells

In this review we summarize recent results which are obtained in the field of structure and functions of cytoplasmic mRNP, or informosomes. These data lead to conclusion, that the informosomal structure of mRNA in eukaryotic cells makes possible the establishment of translational control by masking-demasking of messages.     

Mechanism of the radioprotective effect of cysteamine

The radioprotective effect of cysteamine combined with the modification of the chromatin state by sodium butyrate has been studied using V-79 and CHEL lines of Chinese hamster cells and HeLa cells. Sodium butyrate enhances the chromatin sensitivity to nucleases and removes the radioprotective effect of cysteamine as measured by the yield of cells with chromosome aberrations. As is indicated by changes in the intensity of fluorescence of the DNA-ethidium bromide complex, measured by laser flow cytometry, the protective agent decreases the binding of the dye with both irradiated and nonirradiated DNA whereas ionizing radiation and sodium butyrate increase thereof. It is concluded that the radioprotective effect of cysteamine depends in its ability to reduce the susceptibility of DNA to nucleases.     

Some theoretical aspects of protein coevolution in the ecosystem “phage-bacteria” II. The deterministic model of microevolution

The deterministic model of microevolutionary dynamics of “phagebacteria” ecosystem is analyzed. Primary (and after all decisive) events that determine the dynamics are direct interactions between bacterial reception and viral adsorption proteins. Structure of the model is that under real parameters of adsorption, lysis and reproduction each separate (ith) stage of microevolution comes to end with total lysis of ith population of bacteria by ith population of phage. It is shown however that in the course of joint microevolution both populations pass over some critical sizes when a new pair of antagonistic strains arises with certainty from mutations. As a result it is easy to visualize and simulate by computer the process of successive fixations of such pairs of mutants. This coevolution is the original example of a locally adaptive but globally undirected process which is characterized also by: (1) constant average rate, (2) neutrality of mutations at the moment of their emergence and during the period of “anticipation” of ecological changes, (3) pure adaptivity of the same mutations at the moment of proper fixation and (4) “intrinsic origin” (from the ecosystem dynamics itself) of selective constraints.     

Expression of Photobacterium leiognathi bioluminescence system genes in Escherichia coli

Expression of Photobacterium leiognathi bioluminescence genes under the control of lac, tac, tet promoters in Escherichia coli cells has been studied. The position of the genes for aliphatic aldehyde biosynthesis and for the synthesis of luciferase subunits was identified. The plasmid pBRPL1 has been constructed containing the system of bioluminescence genes devoid of promoter following the polylinker DNA fragment. The plasmid can be used for selection of promoter containing DNA sequences as well as for studying the promoters regulation in process of Escherichia coli cells growth.     

Genetic differentiation in a captive population of the endangered Siberian crane (Grus leucogeranus Pall.)

DNA fingerprinting, followed by multivariate analysis of data, was used to characterize genetic heterogeneity in captive populations of the endangered Siberian and sandhill cranes. The genetic structure revealed reflected the natural population and species distributions. The relevant groups differed not only from each other, but also from interspecies and inter-population hybrids bred in captivity. In this study we have tested an approach to the analysis of population structure based on individual genotypes. Interpretation of fingerprinting data by means of the analytical system applied here is a useful and reliable procedure for the estimation of genetic relationships between individuals.