Phylogeny of anoxygenic filamentous phototrophic bacteria of the family Oscillochloridaceae as inferred from comparative analyses of the rrs, cbbL, and nifH genes

Phylogeny of anoxygenic filamentous phototrophic bacteria (AFPB) of the family Oscillochloridaceae (Oscillochloris trichoides DG6^T and the recently isolated strains Oscillochloris sp. R and C6) was studied based on comparative analyses of the genes coding for 16S rRNA (rrs), ribulose-1,5-bisphosphate carboxylase/oxygenase (cbbL), and nitrogenase (nifH). The sequences of the genes studied proved to be identical in the three strains, which is in agreement with data obtained earlier that showed a lack of differentiating phenotypic distinctions between these strains; therefore, it is proposed that the new strains should be identified as representatives of the species O. trichoides. Using an earlier designed system of oligonucleotide primers and a specially designed additional primer, fragments of the cbbL genes of the “red-like” form I RuBisCO were amplified and sequenced for all of the O. trichoides strains. Analysis of the cbbL genes suggested a separate position of the bacteria studied in the phylogenetic tree, where O. trichoides strains formed an independent branch, which, apart from this species, also included the only studied species of gram-positive facultatively chemoautotrophic bacteria, Sulfobacillus acidophilus. In the phylogenetic tree inferred from the analysis of nifH genes, the bacteria under study also formed a new separate branch, deviating near the root, which indicated a lack of relatedness between them and other phototrophic bacteria. The data obtained support the conclusion that AFPB has an ancient origin and their allocation as one of the main evolutionary lineages of eubacteria, which was made based on the analysis of ribosomal genes.     

Heterocyclic zinc-binding groups for use in next-generation matrix metalloproteinase inhibitors: potency, toxicity, and reactivity

In an effort to improve the zinc-chelating portion of matrix metalloproteinase (MMP) inhibitors, we have developed a family of heterocyclic zinc-binding groups (ZBGs) as alternatives to the widely used hydroxamic acid moiety. Elaborating on findings from an earlier report, we performed in vitro inhibition assays with recombinant MMP-1, MMP-2, and in a cell culture assay using neonatal rat cardiac fibroblast cells. In both recombinant and cell culture assays, the new ZBGs were found to be effective inhibitors, typically 10–100-fold more potent than acetohydroxamic acid. The toxicity of these chelators was examined by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt cytotoxicity assays, which demonstrate that most of these compounds are nontoxic at concentrations of almost 100 μM. To address the possible interaction of sulfur-containing ZBGs with biological reductants, the reactivity of these chelators with 5,5′-dithiobis(2-nitrobenzoic acid) was examined. Finally, thione ZBGs were shown to be effective inhibitors of cell invasion through an extracellular matrix membrane. The data presented herein suggest these heterocyclic ZBGs are potent, nontoxic, and biocompatible compounds that show promise for incorporation into a new family of MMP inhibitors.     

Association of polymorphic markers I/D of gene ACE and A1166C of gene AT2R1 with ischemic chronic heart failure in the Russian and Tatar populations of Bashkortostan Republic

Polymerase chain reaction was used to study the association of polymorphic markers I/D of the angiotensin-converting enzyme gene (ACE) and A1166C of the angiotensin II type 1 receptor gene (AT2R1) with chronic heart failure (CHF) in Russian and Tatar patients that had had myocardial infarction. In Russian patients aged 50 years or younger that had had macrofocal myocardial infarction, the CC genotype of the A1166C polymorphic marker of gene AT2R1 was associated with an increased risk of CHF (OR = 11.36). Genotype DD and allele D of the I/D polymorphic marker of gene ACE were associated with a more severe CHF (functional class III–IV) in Russian patients (OR = 3.50 and 2.06). In Tatar patients, polymorphic markers I/D of gene ACE and A1166C of gene AT2R1 were not associated with CHF.     

Functioning of a CSP310 stress protein is related to the shunting of electron transfer along the respiratory chain of winter wheat mitochondria

Using three-day-old winter-wheat (Triticum aestivum L.) and six-day-old pea (Pisum sativum L.) seedlings as examples, we studied the effects of inhibitors of the electron transfer chain of plant mitochondria on the uncoupling between oxidation and phosphorylation brought about by the CSP310 stress protein. This uncoupling was inhibited by cyanide and by antibodies against CSP310, but not inhibited by antimycin A. It was shown that, in plant mitochondria, the CSP310 stress protein is involved in the electron transfer via shunting the major cytochrome pathway. In this case, the electron transfer bypasses complex II, ubiquinone, and complex III of the mitochondrial respiratory chain and is realized in the following succession: complex I-CSP310-cytochrome c-complex IV. This electron-transfer pathway was found in winter grass mitochondria during the low-temperature stress and resulted in thermogenesis. It was concluded that CSP310 is a thermogenic system, which is activated in winter grass mitochondria during the low-temperature stress.     

Spectral study of the peripheral site of ligand binding in the active center of cholinesterases from different natural sources

An increased ethidium bromide fluorescence at 610 nm was observed in the presence of cholinesterases from some natural sources, and a new fluorescence band appeared in the 500–570 nm region. The data obtained suggest a resonance energy transfer from the cholinesterase-ethidium bromide complex to a free ethidium bromide molecule. The structure of the peripheral ligand binding sites in the active center of bovine erythrocyte acetylcholinesterase, horse serum butyrylcholinesterase, and squid ganglia propionylcholinesterase proved essentially similar.     

Characteristic properties of fluctuating particle fluxes near the last closed flux surface in the course of lower hybrid heating and during a transition into the improved confinement mode in the FT-2 tokamak

Results are presented from experimental studies of the time behavior of the transport processes in the edge plasma of the FT-2 tokamak during auxiliary lower hybrid heating when an internal transport barrier and then an external transport barrier form in the plasma. An analysis of the data on turbulent particle transport in the edge plasma shows that the radial electric field generated inside the plasma column during auxiliary heating plays an important role in both the formation of a transport barrier and the suppression of anomalous transport at the plasma periphery in the postheating phase of the discharge. The mechanism for the formation of a negative radial electric field E _r near the last closed flux surface after the end of the lower hybrid heating pulse is considered. Fluctuation spectra of the particle density and poloidal electric field are presented that characterize the process of suppression of microturbulence at the plasma periphery. The experimental data were obtained with the use of movable multielectrode Langmuir probes.     

Direct comparison of turbulence measurements by Langmuir probe technique and by reflectometry

A comparative analysis of the experimental results from two diagnostic methods—reflectometry and Langmuir probe technique—is carried out, and advantages and drawbacks of these methods are considered; in particular, a comparison is made between their spectral characteristics. The problems arising in interpreting the experimental reflectometric results are thoroughly discussed. To resolve these problems, a stochastic turbulence model with statistical, spectral, and correlation turbulent plasma properties close to the measured ones is constructed. The model is used to simulate the propagation of an electromagnetic wave in a model turbulent plasma. A comparison of the numerical results with the experimental data shows a high spatial locality of reflectometric measurements.     

Synthesis and structure-function study of artificial nucleases on the basis of hemin conjugates with peptide fragments of cell differentiation factor HLDF

A series of octa-hexapeptide fragments of HLDF and their conjugates with hemin were obtained by solid phase peptide synthesis. A relationship between the structure and the nuclease activity of the compounds was established. The effect of various factors (medium pH, the presence of metal ions, complexons, reducers, and buffer composition) on the DNA destruction with hemin peptides was studied. Preliminary information confirming an oxidative mechanism of this process was obtained. The cleavage of plasmid DNA under the action of hemin peptides was studied by the methods of electron microscopy, gel electrophoresis, and atomic force microscopy.     

The genetic rescue of the Florida panther

We examine the consequences of panthers introduced from Texas into south Florida, an area housing a small, isolated, inbred and distinct subspecies ( Puma concolor coryi ). Once part of a continuous, widespread population, panthers became isolated in south Florida more than a century ago. Numbers declined and the occurrence of genetic defects increased. Hoping to reverse the genetic damage, managers introduced eight female panthers from Texas into south Florida in the mid-1990s. This action was highly controversial and we explain the arguments for and against the intervention. We synthesized data systematically collected on the Florida panthers from before, during and after this management intervention. These data include information on movements, breeding, mortality, survivorship and range. There is no evidence that purebred Florida females produce fewer kittens at a later age or less often than do hybrid cats (i.e. those with a Texas ancestor). Hybrid kittens have about a three times higher chance of becoming adults as do purebred ones. Hybrid adult females survive better than purebred females; there is no obvious difference between the males. Males die younger than females, are more often killed by other males and are more likely to disperse longer distances into habitats that are dangerous to them. Hybrids are expanding the known range of habitats panthers occupy and use.