Methacrylate-Reducing Activity of Anaerobic Bacteria Anaeromyxobacter dehalogenans and Denitrovibrio acetiphilus

Microbiology - Periplasmic methacrylate-reducing activity was shown for anaerobic acetate-oxidizing gram-negative bacteria Anaeromyxobacter dehalogenans 2CP-1Т (class Deltaproteobacteria) and...     

Effect of lysozyme on the growth of murine lymphoma and antineoplastic activity of cyclophosphamide]

It was shown that hen egg-white lysozyme (LM) in the dose 100 mg/kg under the daily intragastral use slightly inhibited tumor grown or did not influence significantly upon it and did not change antitumor activity of cyclophosphamide. When used at mice C57Bl/6J with the transplanted ascitic or solid T-cell lymphoma EL4 (syngeneic system). On model of the same tumors in ascitic form at mice-hybrids (C57Bl/6J x DBA2)F1 (semisingeneic system) LM significantly potentiates antitumor activity of cyclophosphamide, though it had no effect on the rate of tumor growth. Potentiation of the effect of cyclophosphamide revealed itself in more slow development of ascite, increased mean life-span and the overall survival, appearance of completely cured animals. Our clinic-laboratory studies have revealed a sharp deficit of endogenic lysozyme in the blood serum of leukemic patients and extremely low lysozyme content in lavage liquid, from leukemic patients, with pneumonia. These data suggest that LM can be useful as a food additive in the complex treatment of oncological patients for enhancing antineoplastic chemotherapy efficacy.     

Effect of motor load on the course of functional maturation of the autonomic control of the cardiovascular system of adolescents

A comparative study of the state of the cardiovascular systems of adolescents not engaged in sports and young athletes of the same age has been performed. According to the indices recorded in the resting state, a relative lag of the functional development of the systems of autonomic control of the cardiovascular system was shown for adolescent nonathletes at an age of 13–14 years as compared with young athletes. This lag is compensated by the age of 15–16 years, but the adequate level of autonomic activity is reached through the activation of central regulatory mechanisms (sympathetic and humoral), with a relatively low contribution of the peripheral vagal and baroreflex mechanisms. This conclusion is confirmed by the results of assessment of the reactivity of the cardiovascular system of adolescents with different levels of motor activity in a functional test with limited pulmonary ventilation.     

Effects of wheat plant inoculation with cytokinin-producing microorganisms on plant growth at increasing level of mineral nutrition

Triticum durum Desf. plants were grown for 11 days in sand culture on nutrient solutions with optimum or lowered content of mineral nutrients. Thereafter, the level of mineral nutrition was increased in some portion of deficient plants. Two days before, plants were inoculated with cytokinin-producing microorganisms of the Bacillus genus. Nutrition deficiency resulted in a decrease in the rate of plant biomass accumulation, which was correlated with the level of active cytokinins in both roots and shoots. After improving the mineral nutrition of noninoculated plants, the rate of their biomass accumulation increased and, by the end of experiment, their shoot fresh weight was 1.5-fold higher than in deficient plants; however, it was still by 20% lower than in plants continuously growing at optimum mineral nutrition. Inoculation resulted in the considerable increase in the cytokinin content in shoots as compared with all other treatments. In this case, after the improvement of plant mineral nutrition, the rates of growth and relative biomass accumulation increased sharply; as a result, these plants had the highest dry and fresh weights. Thus, inoculation with cytokinin-producing bacteria was beneficial for plant growth after their transfer from deficient to sufficient mineral nutrition.     

Comparison of effects of bacterial strains differing in their ability to synthesize cytokinins on growth and cytokinin content in wheat plants

The content of cytokinins and pigments together with the morphological parameters and fresh weight were estimated in durum wheat (Triticum durum Desf.) plants 2–4 days after introduction into their rhizosphere of an aliquot of Bacillus suspension using the strains that differed in their ability of producing cytokinins. The experiments were performed under laboratory conditions at the optimum light intensity and mineral nutrition. Inoculation with microorganisms incapable to synthesize cytokinins did not affect the total cytokinin content in the wheat plants, whereas the presence of cytokinin-producing microorganisms in the rhizosphere was accompanied by a considerable increase in the total cytokinin content and the accumulation of individual hormones. On the second day after inoculation, a dramatic increase in zeatin riboside and zeatin O-glucoside contents was observed in the roots, and at the next day the accumulation of zeatin riboside and zeatin was registered in the shoots of treated plants. The increase in cytokinin content promoted plant growth (the increased leaf length and width and a faster accumulation of plant fresh and dry weight). Plant treatment with a substance obtained from microorganisms incapable to synthesize hormones resulted in the insignificant growth stimulation. Plant treatment with a substance obtained from cytokinin-producing microorganisms increased leaf chlorophyll content; in this case, the level of chlorophylls was comparable to that observed in the plants treated with a synthetic cytokinin benzyladenine. The role of cytokinins of microbial origin as a factor providing for growth-stimulating effect of bacteria on plants is discussed.     

Exogenous zeatin accumulation in wheat root cells shows its role in regulation of cytokinin transport

Here we have shown that 24 hours after addition of zeatin to the nutrient solution the cytokinin content in xylem sap of wheat plants appears to be about 10 times lower that in the nutrient solution. Cytokinins accumulated mostly in roots and not in shoots of treated plants. These data demonstrate the existence of some barrier on cytokinin pathway from the nutrient solution to the plant shoot. With the help of Sudan III an increase in lignin and suberin deposition in the endodermis could be detected, being stronger with the increase in the distance from the root tip. The increase in deposition of suberin and lignin coincided with the decrease in cytokinin immunolabeling in root cells revealed with the help of monoclonal cytokinin antibodies and the second gold-labelled antibodies. Simultaneously exogenous cytokinins accumulated in root stele cells showing that the Casparian band was not only barrier on cytokinin pathway to plant shoot. It is concluded that high cytokinin immunolabe ling in the stele parenchyma cells around the stele vessels demonstrated accumulation of cytokinins by these cells, which could be important in regulation of cytokinin loading to the xylem vessels during there transport to the shoot. The role of cytokinin transporters is discussed.     

Transposable elements in the Animal Kingdom

Transposable elements (TEs) are commonly thought to be of universal occurrence in eukaryotes. Analysis of complete higher eukaryotic genomes confirms TE status as substantial genome components and provides insights into their role in shaping the genome structure of extant eukaryotes. This review addresses several recently investigated problems in transposon biology, including potential roles of promoter organization in transposon function and evolution, the ubiquity of TEs in numerous phyla of the animal kingdom, and possible connections between transposon content and the mode of reproduction.     

Mobile genetic elements and sexual reproduction

Transposable elements (TE) are prominent components of most eukaryotic genomes. In addition to their possible participation in the origin of sexual reproduction in eukaryotes, they may be also involved in its maintenance as important contributors to the deleterious mutation load. Comparative analyses of transposon content in the genomes of sexually reproducing and anciently asexual species may help to understand the contribution of different TE classes to the deleterious load. The apparent absence of deleterious retrotransposons from the genomes of ancient asexuals is in agreement with the hypothesis that they may play a special role in the maintenance of sexual reproduction and in early extinction for which most species are destined upon the abandonment of sex.