Protective action of reactivating factor of <Emphasis Type=Italic>Luteococcus japonicus</Emphasis> subsp. <Emphasis Type=Italic>casei</Emphasis> toward cells of <Emphasis Type=Italic>Escherichia coli</Emphasis> reparation mutants inactivated with UV-light

Reactivating factor (RF) from Luteococcus japonicus subsp. casei had a protective action on UV-irradiated cells of Escherichia coli AB1157 with a native reparation system and on cells of isogenic reparation mutants of E. coli UvrA⁻, RecA⁻, and PolA⁻: the effect resulted in multifold increase of survivability. Defense action of L. casei exometabolite is not connected with stimulating reparation systems in E. coli, and, probably, it is mediated by involvement of the exometabolite in the mechanism of cell division. RF did not provoke the reactivation of E. coli cells inactivated by UV-light.     

OmpC-like porin from Yersinia pseudotuberculosis: Molecular characteristics, physico-chemical and functional properties

Pore-forming protein from the outer membrane of Yersinia pseudotuberculosis cultured at 37°C has been isolated and characterized. Comparative analysis of the primary and three-dimensional structures of this protein and of OmpC porin from E. coli was carried out, functional properties of these proteins have been studied using bilayer lipid membranes (BLM) technique. The degree of homology, molecular mass and pore-forming properties of the isolated porin was found to be closer to those of OmpC porin from E. coli than OmpF porin from Y. pseudotuberculosis. The value of the most probable conductivity of OmpC porin from Y. pseudotuberculosis (0.18 pS) in BLM corresponded to the conductivity of the native trimer of this protein. Using CD spectroscopy, the porins investigated were shown to belong to the β-structured proteins. Data of the primary structure and intrinsic protein fluorescence revealed essential differences in localization and microenvironment of tryptophan residues in the porins investigated. Participation of external loops L2 and L6 in the formation of the antigenic structure of OmpC porin from Y. pseudotuberculosis was demonstrated. On the basis of crystal structure of osmoporin from Klebsiella pneumoniae, three-dimensional models of the monomer and trimer of the Y. pseudotuberculosis porin were obtained. Using Web server AGGRESCAN, the localization of protein structure sites with the increased aggregation capability (hot spots) has been deter-mined. It turned out that some of these zones localize in the region of intramonomeric contacts in the porin trimer; however, a large part of them is located on the external surface of the β-barrel. The process of thermal denaturation has been studied and the melting points of the porins were determined. It was found that significant changes in the microenvironment of the indole fluorophores (especially tryptophan residues of spectral class I) took place in the process of the thermodenaturation of the proteins. These changes preceded the irreversible conformational transition observed for the E. coli porin at 77°C and for the Y. pseudotuberculosis porin at 70°C.     

Use of an inducible reporter gene system for the analysis of auxin distribution in the moss<Emphasis Type="Italic"> Physcomitrella patens</Emphasis>

The plant hormone auxin plays a major role in a variety of growth and developmental responses, even in the more ancient plants-for example, cell differentiation in mosses. Nevertheless, almost nothing is known about the distribution of auxin during moss development. To address this question, we characterised auxin distribution in the moss Physcomitrella patens using auxin-inducible reporter gene systems. Stable transgenic Physcomitrella plants were produced expressing the beta-glucuronidase (GUS) gene driven by the auxin-inducible promoters GH3 and DR5, respectively. Both fusions showed remarkable differences with respect to auxin-induced promoter strength and expression kinetics. A detailed characterisation of the GUS expression pattern in different developmental stages revealed that the highest auxin concentrations were in dividing and ontogenetic young cells.     

The Structure of Uncommon Lipid A from the Marine Bacterium <Emphasis Type="Italic">Marinomonas communis</Emphasis> ATCC 27118<Superscript>T</Superscript>

Lipid A was obtained in a high yield (27%) by the hydrolysis of lipopolysaccharide from the marine gamma proteobacterium Marinomonas communis ATCC 27118^T with 1% AcOH. Using chemical analysis and 1D and 2D NMR spectroscopic and fast atom bombardment mass spectrometric methods, it was shown to be β-1′,6-linked D-glucosaminobiose 1-phosphate acylated with (R)-3-dodecanoyl- or (R)-3-decanoyloxydecanoic acid, (R)-3-{(R)-3-hydroxydecanoyloxy)]decanoic acid and (R)-3-hydroxydecanoic acid at the C2, C2′ and C3 positions, respectively. Uncommon structural peculiarities (a low acylation and phosphorylation degree) of the M .communis lipid A in comparison with those of terrestrial bacteria may be of pharmacological interest. The potential physiological meaning of this lipid A and compounds of similar structure are discussed.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 4, 2005, pp. 404–413.Original Russian Text Copyright © 2005 by Vorob’eva, A. Dmitrenok, P. Dmitrenok, Isakov, Krasikova, Solov’eva.The article was translated by the authors.     

Interactions of Platinum and Ruthenium Coordination Complexes with Pancreatic Phospholipase A2 and Phospholipids Investigated by MALDI TOF Mass Spectrometry

Phospholipase A₂ is involved in propagation of inflammatory processes and carcinogenesis through its role in phospholipid metabolism, and release of arachidonic acid and lysophospholipids. Recent findings on correlation between elevated PLA₂ activity and metastatic cancer render this enzyme an attractive target for cancer therapy. On the other hand, due to a broad range of oxidation states under physiological conditions and a high affinity for protein binding, platinum and ruthenium coordination complexes are promising candidates for PLA₂ inhibitors. In this article, we discuss the interactions of Pt and Ru coordination complexes with PLA₂ and phospholipids, as well as the application of MALDI‐TOF mass spectrometry for screening PLA₂ inhibitors. Owing to the ability of this technique to simultaneously detect and monitor changes in substrate and product concentrations, the inhibitor mechanisms of both Pt and Ru complexes with various ligands were determined.     

Morphokaryological variability and divergence of stargazers (Uranoscopus, perciformes) from the Mediterranean Sea basin: I. Divergence and taxonomic state of the Black Sea Stargazer

Based on museum collections, the variability of morphological characters of stargazers (Uranoscopus, Uranoscopidae) from different seas of the Mediterranean Sea basin have been studied. On the basis of the obtained results and data on the karyological divergence of the previously studied populations, stargazers of the Black Sea are regarded as an independent subspecies, Uranoscopus scaber anostomus, differing from the Mediterranean Sea populations in relatively long ventral fins, whose length usually exceeds half of the head length, the presence in most individuals of not less than 12 pyloric caeca, chromosome polymorphism with 2n = 28?C32, NF = 50, and the presence in the karyotype of a pair of marker small metacentric chromosomes. Morphological characters suitable for analysis of morphological divergence of populations of the Mediterranean region have been revealed.     

Conformational properties of nuclear protein HMGB1 and specificity of its interaction with DNA

Changes in secondary structure of DNA and non-histone chromosomal protein HMGB1 during the formation of the complex have been studied by circular dichroism and UV spectroscopy. It was demonstrated that the HMGB1 protein is able to change its secondary structure upon binding to DNA. Based on the assumption that there are two spectroscopically distinguishable forms of the HMGB1 in solution, we estimated the fraction of bound protein. The fraction of bound protein decreases at higher protein to DNA ratios r from 0.48 at r = 0.13 to 0.06 at r = 2.43. It was shown that HMGB1 is able to induce considerable changes in DNA structure, even when the amount of protein actually bound is low.     

The lipid status of young of the year mykiss <Emphasis Type="Italic">Parasalmo mykiss</Emphasis> and coho salmon <Emphasis Type="Italic">Oncorhynchus kisutch</Emphasis>

The young of the year mykiss Parasalmo mykiss and coho salmon Oncorhynchus kisutch which perform downstream migration and which stay in the coastal zone during the period of primary dispersion represent different phenotypic groups. They differ in weight, length, and lipid status. Such differentiation is a factor controlling the formation of intrapopulation diversity and of the life strategy of fish. It may determine the timing of smoltification in the future and, further on, of the return for spawning. There were found some analogies and differences in characteristics of lipid metabolism in the investigated species. The content of total lipids decreases by autumn in underyearlings of both species. Furthermore, changes in the content of particular lipid fractions are multidirectional and various scaled, seemingly being related to physiological preparation for the wintering.     

OmpC-like porin from outer membrane of Yersinia enterocolitica: Molecular structure and functional activity

OmpC-like porin was isolated from the outer membrane (OM) of Yersinia enterocolitica cultured at 37°C (the “warm” variant) and its physicochemical and functional properties were studied. The amino acid sequence of OmpC porin was established, and the primary structure and transmembrane topology of this protein were analyzed in comparison with the OmpF porin isolated from Y. enterocolitica cultured at 6°C (the “cold” variant). Both porins of Y. enterocolitica had a high homology degree (65%) between themselves and with OmpC and OmpF porins from OM of Escherichia coli (58 and 76% homology, respectively). The secondary structure of OmpC and OmpF porins from OM of Y. enterocolitica consists of 16 β-strands connected by short “periplasmic” and longer “extracellular” loops with disordered structure, according to the topological model developed for porins of E. coli. The molecular structures of OmpC and OmpF porins of Y. enterocolitica have significant differences in the structure of the “extracellular” loops and in the position of one of three tryptophan residues. Using the bilayer lipid membrane (BLM) technique, pores formed by OmpC porin of Y. enterocolitica were shown to differ in electrophysiological characteristics from channels of OmpF protein of this microorganism. The isolated OmpC porin reconstructed into BLM displayed functional plasticity similarly to OmpF protein and nonspecific porins of other enterobacteria. The conductivity level of the channels formed by this protein in the BLM was regulated by value of the applied potential.     

Distribution of cryptic shrew species of the genus Sorex (Mammalia) on the plain between the Don and Kuban rivers as inferred by molecular markers

Microsatellite and mtDNA markers have been used to identify two pairs of cryptic species Sorex araneus L. (Sorex satunini Ogn.) and Sorex minutus L. (S. volnuchini Ogn.). The new data were obtained on the distribution of these species on the plain between the Don and Kuban rivers. The shrew S. volnuchini and Caucasian mole are distributed on the plain areas up to the Eya River. The endemic species of the Caucasus, the shrews S. satunini and S. volnuchini, are widely distributed across the valleys alongside small streams on the steppe plain. Both species are most abundant on thick grasslands, bushy scrub, and deciduous woodlands. They don??t show any clear differences in habitat preferences.