Regulatory effect of microbial alkyloxybenzenes of different structure on the stress response of yeast

The effect of alkyloxybenzenes (AHBs) belonging to the class of alkylresorcinols differing in the degree of hydrophobicity--C7-AHB and more hydrophobic Cl12-AHB--on the resistance of Saccharomyces cerevisiae cells to heat shock and oxidative stress of lethal intensity was studied. Depending on structure and concentration, AHB added 2 h before exposure to stress had either an antistress or stress-potentiating effect on yeast cells in the mid-logarithmic growth phase. C7-AHB at concentrations 0.25-0.5 g/l caused a two- to fivefold increase in the resistance of yeast cells to hydrogen peroxide (30-150 mM), whereas Cl2-AHB reduced it at all concentrations. C7-AHB and Cl2-AHB had a similar effect on yeast subjected to heat shock (45 degrees C, 30 min). It was found that the degree of the protective effect of C7-AHB and potentiating effect of Cl2-AHB depended on the nature of the stressor, being more pronounced in heat shock. The environmental significance of the antistress and stress-potentiating effects of microbial AHBs is discussed.     

Callose accumulation during treatment of tomato (Lycopersicon esculentum L.) cells with biotic elicitors

Time-course of induced accumulation of callose in tomato cells has been studied. Localization of callose in L. esculenthum cells was investigated by fluorescent microscopy technique, and the optimal time for its determination was found. Callose accumulation in tomato cells treated with different biotic elicitors was determined. Nonlinear dependence between callose accumulation and concentration of chitin oligomers (with 3-5 N-acetylglucosamine fragments) was established. Increasing of callose accumulation in tomato cells was proportional to the increase of concentration ofchitin dimer and chitosan in the culture medium.     

The analytical review of the schemes of the acute radiation disease treatment used in experiment and in clinic

The analysis of the original sources showed that there are some differences in approaches to radiation injuries treatment used mainly by Russian and foreign researches in their experiments. In Russian radiobiology the main way was the single usage of high molecular substances of different chemical structure and of natural origin soon after radiation exposure. These substances were designated then as cytokine inductors. Foreign researchers investigated in the beginning analogous substances too, but then--recombinant cytokines exclusively. In native radiobiology the urgent (in limits of 2 h) and early (in limits of 6-24 h) pathogenic therapy develops already for a long time. There are preparations, betaleukine (recombinant human interleukine 1 beta) and dezoksinat (degraded DNA), as results of developing the directions. Both have licenses on the administration at radiation accidents. But the issues of various medicaments optimal combinations in a common scheme of early (in first 24 h) medical help remain undefined accurately. The consensus protocol of radiation injuries treatment in clinic consists of the supportive therapy (aseptic conditions, wide antimicrobic antibiotics, thrombocytes and erythrocytes transfusions) and the myelostimulation therapy by cytokine combinations. The hemopoietic stem cells transplantation in cases of severe radiation damages treatment remains under question in the reason of immunological conflict between a host and a graft.     

The mechanisms of 232Th and of Ce (III) toxic action on Chlorella vulgaris Beijer. Estimation of 232Th radiation impact contribution into toxic effect induced

232Th and Ce (III) toxic effects and its modifications with caffeine and D,L-buthionine-(S,R)-sulphoximine on Chlorella vulgaris Beijer were studied using an optical density measure after 24 hours growth. Concentrations of 232Th or of Ce--toxic effect relationship were shown to be nonlinear. In the first (nontoxic) concentration range (for Ce 0.036-1.642 micromol/L and for 232Th 0.001-1.551 micromol/L) algae biomass production registered by optical density do not significantly differ from the control one. In the second (toxic) concentration range dose-effect relationship for 232Th is characterized with quadratic dependence and in the case of Ce--with exponential dependence. 232Th radiation component contribution into effect observed is appeared as induction of DNA damages additional to spontaneous at the radionuclide concentration (equal to 0.345 micromol/L) that is three times lower than in case of the non-radioactive chemical analog Ce (1.071 micromol/L).     

The effects of inbreeding and low temperature on the pattern of chromosome synapsis in the ovarian nurse nuclei of Drosophila melanogaster strains

The effects of inbreeding and low temperature on the pattern of homologous chromosome synapsis in ovarian nurse cell nuclei of Drosophila melanogaster strains were studied. Exposure to decreased temperature (16 degrees C) caused a noticeable increase in the rate of asynapses of homologous chromosomes, whereas this effect was insignificant for F30 inbreeding generation. Long-term inbreeding has a substantial effect on the relative positions of chromosomes in the nurse cell nuclei. This is visually evident only in the interstrain hybrids between highly inbred strains LA (F923) and HA (F923) or between either strain and laboratory strain Canton S or the flies from the natural population, where abnormalities in homologous chromosome synapsis are observed in virtually all nuclei.     

Valentin Sergeevich Kirpichnikov: on the 100th anniversary of his birth (1908-1991)

Valentin Sergeevich Kirpichnikov is an outstanding Russian biologist, geneticist, and evolutionist. In his work, the true interest to the theory of evolution was harmoniously combined with long-term successful research into fish genetics and breeding. In 1987, Kirpichnikov published a fundamental treatise entitled "Fish Genetics and Breeding," which was immediately translated into English, German, and Japanese and still remains the most comprehensive handbook in this field. The authority of Kirpichnikov was confirmed by his election to the International Association of Aquaculture and an expert of the leading international organization on food and agriculture, FAO, with the United Nations. During the hard years in the history of Soviet biology, the courage and fidelity to the principles in defending the scientific biology and opposing Lysenko's obscurantism won Valentin Sergeevich the deserved name of a "knight of science". His mode of speech at the seminars and in discussions was unhurried, calm, and fitting. Yet especially important moments supplemented his baritone with hard metal modulations, which revealed the concealed passion and conviction in the defended truth.     

Dissection of ammonium uptake systems in Corynebacterium glutamicum: mechanism of action and energetics of AmtA and AmtB

Corynebacterium glutamicum has two different Amt-type proteins. While AmtB has a low substrate affinity and is not saturable up to 3 mM methylammonium, AmtA has a high substrate affinity and mediates saturable, membrane potential-dependent transport, resulting in a high steady-state accumulation of methylammonium, even in the absence of metabolic trapping.     

The E3 ubiquitin ligase NEDD4 is an LC3-interactive protein and regulates autophagy

The MAP1LC3/LC3 family plays an essential role in autophagosomal biogenesis and transport. In this report, we show that the HECT family E3 ubiquitin ligase NEDD4 interacts with LC3 and is involved in autophagosomal biogenesis. NEDD4 binds to LC3 through a conserved WXXL LC3-binding motif in a region between the C2 and the WW2 domains. Knockdown of NEDD4 impaired starvation- or rapamycin-induced activation of autophagy and autophagosomal biogenesis and caused aggregates of the LC3 puncta colocalized with endoplasmic reticulum membrane markers. Electron microscopy observed gigantic deformed mitochondria in NEDD4 knockdown cells, suggesting that NEDD4 might function in mitophagy. Furthermore, SQSTM1 is ubiquitinated by NEDD4 while LC3 functions as an activator of NEDD4 ligase activity. Taken together, our studies define an important role of NEDD4 in regulation of autophagy.     

Kinetic chemiluminescence as a method for the study of free radical reactions

The review gives concepts of analysis of kinetics of complex reactions with the participation of free-radicals. The concepts are based on the comparison of the kinetic curves of the chemiluminescent reactions in the presence of a physical enhancer coumarin C-525 with the simulated kinetic functions. This method was applied to the investigation of the mechanism of a branched-chain reaction of lipid peroxidation in biological and phospholipid membranes as well as to the effect of antioxidants and determination of their activities. It was also used for studying the reaction of the formation of free radicals in the complex of cytochrome c with cardiolipin. This reaction plays a key role in the initiation of apoptosis.