Inhibition of leucyl-tRNA-synthetases by modified ATP analogs

The interaction between modifying ATP analogs containing alkylating or phosphorylating groups in the polyphosphate moiety of the ATP molecule and leucyl-tRNA synthetases from cytoplasm and chloroplasts of Euglena gracilis (strain Z) was studied. It was shown that most of the ATP analogs irreversibly inhibit the cytoplasmic enzyme, having no inhibiting effect on the chloroplast synthetase. The kinetic constants K1 and k2 for the interaction between the most effective irreversible inhibitors and the cytoplasmic enzyme were determined. The data on the protection of the enzyme activity by substrates against irreversible inhibition suggest, that the effect of the adenosine 5'-(beta-chloroethyl phosphate) is directed to the ATP-binding site of the cytoplasmic enzyme, whereas the mixed anhydride of AMP and mesithylene carbonic acid acts predominantly on the binding site of 3'-terminal adenosine of the tRNALeu molecule. ATP analogs may be effectively used for affinity labelling of the cytoplasmic leucyl-tRNA synthetase.     

Procedure for isolating nisin from Streptococcus lactis

The paper describes a method for obtaining the antibiotic nisine from Streptococcus lactis str. MSU via 50% acetic acid extraction. The concentrate is dried in the Anhydro spray drier (Denmark). The preparation is inactivated during a one-year storage in the refrigerator by 20-25%.     

An Exposure to the Oxidized DNA Enhances Both Instability of Genome and Survival in Cancer Cells

Background

Cell free DNA (cfDNA) circulates throughout the bloodstream of both healthy people and patients with various diseases and acts upon the cells. Response to cfDNA depends on concentrations and levels of the damage within cfDNA. Oxidized extracellular DNA acts as a stress signal and elicits an adaptive response.

Principal Findings

Here we show that oxidized extracellular DNA stimulates the survival of MCF-7 tumor cells. Importantly, in cells exposed to oxidized DNA, the suppression of cell death is accompanied by an increase in the markers of genome instability. Short-term exposure to oxidized DNA results in both single- and double strand DNA breaks. Longer treatments evoke a compensatory response that leads to a decrease in the levels of chromatin fragmentations across cell populations. Exposure to oxidized DNA leads to a decrease in the activity of NRF2 and an increase in the activity of NF-kB and STAT3. A model that describes the role of oxidized DNA released from apoptotic cells in tumor biology is proposed.

Conclusions/Significance

Survival of cells with an unstable genome may substantially augment progression of malignancy. Further studies of the effects of extracellular DNA on malignant and normal cells are warranted.     

The Effect of Microwave Radiation on Cell Sensitivity to Monohydric Alcohols in Platelet-Rich Plasma

Blood cell aggregation in platelet-rich plasma (PRP) supplemented with the aggregation inducer ristomycin was studied following exposure to low-intensity extremely high frequency (EHF) radiation. Primary alcohols were used to stimulate partial degradation of the protein–lipid bilayer in the cell membrane. Exposure to EHF radiation was shown to decrease the extent of ristomycin-induced platelet aggregation and to change the slope of the aggregation curve. A biphasic character was observed for the effect of alcohols on platelet aggregation. The first phase was characterized by a decrease in aggregation and a decrease in the slope of the aggregation curve. In the second phase, platelet aggregation and the aggregation curve slope increased with the increasing alcohol concentration. A possible mechanism is discussed for the observed effects.

     

Genomic and proteomic profiles of <Emphasis Type="Italic">Acholeplasma laidlawii</Emphasis> strains differing in sensitivity to ciprofloxacin

As a result of comparative analysis of complete genomes as well as cell and vesicular proteomes of A. laidlawii strains differing in sensitivity to ciprofloxacin, it was first shown that the mycoplasma resistance to the antibiotic is associated with the reorganization of genomic and proteomic profiles, which concerns many genes and proteins involved in fundamental cellular processes and realization of bacterial virulence.     

Genetic diversity of wild reindeer <Emphasis Type="Italic">Rangifer tarandus</Emphasis> L. from the eastern part of the Kola Peninsula: Polymorphism of the mtDNA control region

Based on the results of the analysis of nucleotide sequence polymorphism in the hypervariable fragment (left domain) of the mtDNA control region (D loop), the genetic diversity of wild reindeer from the eastern part of the Kola Peninsula (Murmansk oblast, Terskii region) was studied. Low values of the genetic diversity indices for Eurasian wild reindeer were detected. The effect of domestic reindeer breeding on the development of genetic diversity of the wild reindeer population in the studied region (indicating a low degree of hybridization of domesticated and wild reindeer) was estimated.     

The Baseline Level of Cytogenetic Damage in Lymphocytes and Buccal Epitheliocytes of Lung Cancer Patients

Russian Journal of Genetics - The results of the study of chromosomal aberrations and micronuclei in blood lymphocytes, as well as micronuclei in buccal epithelium cells of 50 untreated men with...     

The Effect of Environmental Electromagnetic Radiation on Associate Formation in Aqueous Solutions

Biophysics - Abstract—We present the results of studies of the nature of the features known in modern biophysics in the manifestation of the associative properties of aqueous solutions of...     

A new pentanucleotide STR-marker, located in the intron of the ING1 tumor suppressor gene and its allelic polymorphism

DNA samples of unrelated subjects from the Volga-Ural region of Russia were examined to study allele polymorphism of the pentanucleotide repeat (TTGTG)8 localized to an intron of the tumor suppressor gene ING1. STR marker was registered in the EMBL database with the accession number AJ277387. In a sample of 119 individuals, three pentanucleotide alleles consisting of seven, eight, and nine repeated monomers were revealed. The allele frequencies were 0.24, 0.74, and 0.02, respectively. Heterozygosity was 0.45. On the basis of these data, the repeat can be regarded as a polymorphic STR marker for the ING1 gene and used in population and clinical studies.