Expression of the amino acid operons in Escherichia coli strains with an altered transcription and translation apparatus. IV. The effect of mutations disturbing the coupling of the transcription and translation processes on ilv-operon expression in cells carrying the mutation in the spoT gene

The rate of adaptation of Escherichia coli K-12 NF930 spoT1 cells with elevated intracellular level of ppGpp to various minimal media was studied. It has been found that the rate of adaptation of spoT cells, like that of parent and rel strains, depends mainly on the rate of derepression of the ilv operon. The maximal rate of the ilv operon derepression was observed when an optimal concentration of ppGpp was maintained in cells. Derepression of the ilv operon is sharply delayed when the level of ppGpp is elevated or reduced. Mutations altering the translation system do not change the rate of adaptation of spoT cells. Rifampicin resistance mutations which altered the structure of RNA polymerase change the rate of adaptation of spoT cells to minimal media, especially to those containing serine at high concentrations. The possible role of serine in the regulation of ppGpp degradation system is discussed.     

Inversion polymorphism in malaria mosquito Anopheles messeae. Part X. Resistance of larvae with different genotypes to toxins of crystal-forming bacteria Bacillus thuringiensis subsp. israelensis (serovar H14)

Insensibility of larvae with different chromosomal inversions to the toxins of Bacillus thuringiensis subsp. israelensis (Bti) was examined. It has been shown that larvae with inversion combinations XL0(XL1)2R0-3R0-3L0 had greater variability after treatment with Bti than larvae with inversions XL1(XL2)2R1-3R1-3L1(3L0). The former inversion combinations were previously shown to dominate in the south of the species area and to be supported by K-selection. The latter inversion combinations form "northest" karyotypes and are supported by r-selection. It is obvious that genetic effects of treatments with Bti depend on the population's structure and the directions of natural selection. The decrease in the level of heterozygotes after treatment of larvae with Bti reflects destruction of the system of genetic homeostasis in the natural populations of A. messeae.     

Chromosomal polymorphism in the populations of malaria mosquito <Emphasis Type="Italic">Anopheles messeae</Emphasis> (Diptera,Culicidae) in the Volga region

We studied the species composition and chromosomal variability of malaria mosquitoes in the Volga Basin (Upper, Middle, and Lower Volga regions). We investigated larvae karyotypes of sibling species of the Anopheles maculipennis group. We calculated the frequencies of chromosomal inversions in the local populations of the dominant species An. messeae. We discovered that karyotypic structure of An. messeae populations depends on landscape-climatic zones. Populations of the Upper, Middle and Lower Volga differ in frequency of chromosome inversions XL, 2R, 3R, and 3L.     

<Emphasis Type="Italic">Paralepidapedon variabile</Emphasis> sp. n. (Trematoda,Lepocreadioidea, Lepidapedidae) and other representatives of the genus <Emphasis Type="Italic">Paralepidapedon</Emphasis> from Antarctic fish

In the Ross Sea and Amundsen Sea, four representatives of the genus Paralepidapedon—Paralepidapedon cf. dubium Prudhoe et Bray 1973 sensu Sokolov et Gordeev 2013, P. lepidum (Gaevskaya et Rodyuk 1988), Paralepidapedon sp., and P. variabile sp. n.—were found in demersal fishes Muraenolepis marmorata and Macrourus whitsoni. Paralepidapedon variabile sp. n. is described from Muraenolepis marmorata in the Amundsen Sea. Paralepidapedon variabile sp. n. differs from other species of the genus Paralepidapedon by the position of the anterior border of the vitellarium at the level of the anterior edge of the ventral sucker or genital pore and by the highly variable shape of the testes: from roundish with a smooth edge to sinuate–lobate. Paralepidapedon lepidum was found for the first time in the Antarctic.     

Oxidation Processes and the Content of Immune Complexes in Immunocompetent Organs of Char in the Basin of Kronotskoe Lake

Biology Bulletin - The content of nonspecific immune complexes, products of lipid peroxidation, and antioxidant activity in the liver, kidney, and spleen were studied in Salvelinus schmidti, S....     

Nonquasineutral model of an equilibrium Z-pinch

A fundamentally new approach is proposed for describing Z-pinches when the pinch current is gov-erned to a large extent by strong charge separation, which gives rise to a radial electric field in the nonquasineutral core of the pinch. In the central pinch region with a characteristic radius of about $r_0 \sim \sqrt {J_0 /en_e c}$ , part of the total pinch current J ₀<J, is carried by the drifting electrons and the remaining current is carried by ions moving at the velocity v _iz ～c(2eZJ/m _i c ³) in the peripheral region with a radial size of c/ω_pi. In the nonquasineutral core of a Z-pinch, the radial ion “temperature” is on the order of ZeJ ₀/c. The time during which the non-quasineutral region exists is limited by Coulomb collisions between the ions oscillating in the radial direction and the electrons. Since the magnetic field is not frozen in the ions, no sausage instability can occur in the non-quasineutral core of the Z-pinch. In the equilibrium state under discussion, the ratio of the radial charge-separation electric field E ₀ to the atomic field E _a may be as large as $E_0 /E_a \sim 137^2 (a_0 \omega _{pe} /c)\sqrt {J/J_{Ae} }$ , where a ₀ is the Bohr radius.     

A distal methyl substituent attenuates mitochondrial protein synthesis inhibition in oxazolidinone antibacterials

Oxazolidinone analogs bearing substituted piperidine or azetidine C-rings are described. Analogs with a methyl group at the 3-position of the azetidine ring or the 4-position of the piperidine ring exhibited reduced mitochondrial protein synthesis inhibition while retaining good antibacterial potency.