Physicochemical properties of malate dehydrogenase from the bacterium Rhodopseudomonas palustris strain f8pt

Electrophoretically homogenous isoforms of malate dehydrogenase with different quaternary structure were prepared from Rhodopseudomonas palustris strain f8pt cultured photolithoheterotrophically on malate and acetate. By selective inhibition of the tricarboxylic acid cycle or glyoxylate cycle, it was shown that the dimeric isoform of the enzyme is responsible for Krebs cycle functioning and the tetrameric isoform is involved in functioning of the glyoxylate cycle.     

Microbial producers of plant growth stimulators and their practical use: A review

The ability of pro- and eukaryotic microorganisms to synthesize growth-stimulating phytohormones is reviewed, with emphasis on pathways of biosynthesis of these compounds and their effects on physiological and biochemical properties of the producers. Phytohormones are viewed as specific mediators in interactions between various organisms inhabiting the same ecological niche, the biological role of which is not limited to processes taking place in plants. In addition to setting forth theoretical aspects of this problem, the review underscores the need to utilize such producer microorganisms in plant cultivation and biotechnology.     

Distribution of Ichthyoplankton in Relation to Specifics of Hydrological Regime off the Crimean coast (the Black Sea) in the Spring–Summer Season 2017

Journal of Ichthyology - The paper presents characteristics of the species composition, spatial distribution, and trophic interactions of ichthyoplankton and zooplankton in the spring–summer...     

Hyperbaria and stress

Performed on rats was study of the cause of appearance of stress reaction at action of hyperbaria upon organism. It was established that at the 5-h long action of gas mixtures (oxygen—nitrogen and oxygen—argon) under pressure of 0.35 and 0.5 MPa and partial pressure of oxygen of 0.02–0.03 MPa in camera 300 l in volume there was clearly realized stress confirmed by the corresponding markers. The appearance of stress was connected with density of gas mixture, which amounted to 6 g/l, that mechanically makes breathing difficult. On the other hand, use for respiration mixtures of elegas (SF6) with density of 6 g/l at normal pressure produces pronounced stress. At equal density, no difference was revealed in action of nitrogen, argon or elegas. Thus, use of high pressures requires light gases (helium, hydrogen, neon) that have low density.     

K<Superscript>+</Superscript>/Na<Superscript>+</Superscript> in the animal extracellular fluid at weathering of granitoids and problem of the origin of life

Leaching of granitoids of the paleoproterozoic age was performed from several seconds to 360 days in water solutions (pH < 6.0) in the oxygen or argon medium. Under these conditions the entrance of K⁺ into the solution has been shown to occur at the higher rate than that of Na⁺. The obtained data are considered as evidence in favor of a possibility of the existence at the earlier stages of the Earth geologic history of water reservoirs with predominance of K⁺ over Na⁺. The K⁺/Na⁺ ratio exceeding 1 has been shown in prokaryotes, in cells and tissues of the free living and parasitic species of invertebrate and vertebrate animals. At the same time, in the extracellular fluid of the fresh water, marine, and terrestrial animals, in which the Na+ concentration varies from 13 to 482 mmol/l, the K⁺/Na⁺ ratio is preserved at the level of 0.034 ± 0.001. These results are discussed in relation to the problem of origin of protocells and of concentration ratios of monovalent cations in water phases of multicellular organisms.     

New World Stictocladius Edwards (Diptera: Chironomidae)

The orthocladiine Chironomidae genus Stictocladius Edwards was described originally from South America. Although recognised subsequently as present also in Australia and New Zealand, the true diversity in the Neotropics has remained unclear. After more than a decade of collections of both isolated adults and aquatic immature stages, we can recognise several new taxa and associate some immature stages. Thus, we describe Stictocladius prati n. sp. as male, female, pupa and larva; Stictocladius acutus n. sp. and Stictocladius acrilobus n. sp. as male, female and pupa; Stictocladius fimbriatus n. sp. as male and female; Stictocladius fovigus n. sp. and Stictocladius nudiventer n. sp. as male and pupa; and Stictocladius privicalcar n. sp. and Stictocladius prostatus n. sp. each as male imago alone. The male and female of Stictocladius pulchripennis Edwards is redescribed and the pupa described. The male and female of Stictocladius flavozonatus Edwards and the male of Stictocladius calonotum Edwards are described. Five pupal types are described: Stictocladius sp. A (near S. acrilobus), Stictocladius sp. B (possibly S. calonotum), Stictocladius sp. C (near S. calonotum), Stictocladius sp. D (possibly S. flavozonatus) and Stictocladius sp. E with uncertain affinity. A larva from Chile of the Stictocladius ??sofour type?? (Stictocladius sp. F) and an unreared larva from North America (Stictocladius sp. G) possibly belonging to S. acutus are described. Keys to named Neotropical male and female imagines of Stictocladius and to all pupal forms of Neotropical Stictocladius are provided. Some data concerning fourth instars of Stictocladius are presented. Means of differentiation from putative sister taxon Lopescladius are discussed.     

Peculiarities of development in the marine brown alga <Emphasis Type="Italic">Alaria angusta</Emphasis> Kjellman, 1889 (Alariaceae: Ochrophyta) under laboratory-controlled conditions

This paper describes the formation of gametophytes and the early stages of the development of sporophytes in the kelp seaweed Alaria angusta from Kamchatka. To establish laboratory cultures we used zoospores obtained from A. angusta sporophytes collected on October 29, 2014. The gametophytes were grown under different conditions: at 6–7°С and natural light and at 10°С and illumination with cool white fluorescent bulbs, 30 μmol photon m^–2 s^–1, 12: 12 h L: D cycle. In the first case (natural light, 6–7°С), the vegetative growth of male and female gametophytes lasted for more than 4 months; maturation of sexual products occurred 144 days after germination of the embryospores. In the second case (artificial light, 10°С), rapid development of the gametophytes occurred; the first juvenile sporophytes appeared on the 10th day after the zoospores settled onto the substrate. Our data contribute to understanding of the regulatory effect of temperature and light on the peculiarities of species vegetation in the natural environment and formation of the age structure of the species population, one particular feature of this process is the continuous appearance of juvenile sporophytes in the warm period of the year.