Stability analysis of an age-structured model of cervical cancer cells and HPV dynamics.

Stability analysis of an autonomous epidemic model of an age-structured sub-populations of susceptible, infected, precancerous and cancer cells and unstructured sub-population of human papilloma virus (HPV) (SIPCV epidemic model) aims to gain an insight into the features of cervical cancer disease. The model considers the immune functional response of organism to the virus population growing by the HPV-density dependent death rate, while the death rates of infected, precancerous and cancerous cells do not depend on the HPV quantity because the immune system of organism does not respond to its own cells. Interaction between susceptible cells and HPV is described by the Lotka-Voltera incidence rate and leads to the growth of infected cells.

Asymptotic stability of delayed consumer age-structured population models with an Allee effect.

In this article we study a nonlinear age-structured consumer population model with density-dependent death and fertility rates, and time delays that model incubation/gestation period. Density dependence we consider combines both positive effects at low population numbers (i.e.

Steady states and outbreaks of two-phase nonlinear age-structured model of population dynamics with discrete time delay.

In this paper we study the nonlinear age-structured model of a polycyclic two-phase population dynamics including delayed effect of population density growth on the mortality. Both phases are modelled as a system of initial boundary values problem for semi-linear transport equation with delay and initial problem for nonlinear delay ODE. The obtained system is studied both theoretically and numerically.

[Anaerobic bacteria involved in the degradation of aromatic sulfonates to methane].

An anaerobic microbial consortium that degrades benzene- and p-toluenesulfonate to form methane and fatty acids has been produced. Pure cultures of three strains of anaerobic spore-forming bacteria Clostridium spp., as well as the sulfate-reducing bacteria Desulfovibrio sp.

Recent Origin of the Methacrylate Redox System in Geobacter sulfurreducens AM-1 through Horizontal Gene Transfer.

The origin and evolution of novel biochemical functions remains one of the key questions in molecular evolution. We study recently emerged methacrylate reductase function that is thought to have emerged in the last century and reported in Geobacter sulfurreducens strain AM-1. We report the sequence and study the evolution of the operon coding for the flavin-containing methacrylate reductase (Mrd) and tetraheme cytochrome с (Mcc) in the genome of G.

[Hygienic problems in the location of modern wind electric power stations in their design].

Hygienic aspects of the placement of wind power plants (WPP) in connection with the intensive development of wind power and the lack of systematic information on their effects of the environment and living conditions of the population are becoming more actual. In the article there are considered results of the sanitary-epidemiological expertise of the construction project of three modern large wind farm (the South - Ukrainian, Tiligulskaya and Pokrovskaya) with a total capacity offrom 180 to 500 MW of wind farms with 2.3 MW power generators of wind turbines.

[Respiratory activity of yeast Yarrowia lipolytica under oxidative stress and heat shock].

Heat shock (45 degrees C) and the effect of oxidants (H2O2) resulted in a decrease of the respiratory activity of yeast cells and their survival rate. Increased resistance to stress effects after mild heat treatment (37 degrees C) or treatment with a nonlethal dose of oxidants (0.5 mM H2O2 for 60 min) was accompanied by appearance of an alternative (cyanide-resistant) oxidative pathway in the mitochondria, which promotes survival due to retention of the capacity for ATP synthesis in the first coupling point at the level of endogenous NADH dehydrogenase.

[Interrelation between the pathways of isoprenoid biosynthesis and carbon source catabolism in anaerobic and facultatively anaerobic bacteria].

Data on the interrelation between the pathways of the carbon source catabolism and isoprenoid biosynthesis in anaerobic and facultatively anaerobic bacteria were obtained. Two pathways of isoprenoid biosynthesis (nonmevalonate and mevalonate) were revealed in the representatives of the genus Clostridium. The non-mevalonate pathway of isoprenoid biosynthesis and the glycolytic pathway of substrate oxidation are typical of glucose-grown bacteria, whereas the pentose phosphate cycle operates in xylose-grown bacteria.

[Adaptation of the yeast Yarrowia lipolytica to heat shock].

The adaptive response of the yeast Yarrowia lipolytica to heat shock has been studied. Experiments showed that, after 10 min of incubation at 45 degrees C, the survival rate of Yarrowia lipolytica cells was less than 0.1%.

[Tolerance of the yeast Yarrowia lipolytica to oxidative stress].

The adaptive response of the yeast Yarrowia lipolytica to the oxidative stress induced by the oxidants hydrogen peroxide, menadione, and juglone has been studied. H2O2, menadione, and juglone completely inhibited yeast growth at concentrations higher than 120, 0.5, and 0.

[Biosynthesis of naphthoquinone pigments by fungi of the genus Fusarium].

We studied biosynthesis of colored naphthoquinone metabolites by Fusarium decemcellulare, F. graminearum, and F. bulbigenum fungi.

[Isoprenoid pigments in representatives of the family Microbacteriaceae].

By using fosmidomycin and mevinolin (inhibitors of the synthesis of isoprenoid pigments), spectrophotometry, and mass spectrometry, the presence of isoprenoid pigments is shown in 71 of the 78 strains under study. All of these strains belong to 11 genera of the family Microbacteriaceae. Yellow, orange, and red pigments are found to have absorption spectra typical of C40-carotenoids.

[Prevalence of nonmevalonate and mevalonate pathways for isoprenoid biosynthesis among bacteria of different systematic groups].

The effect of fosmidomycin and mevinoline, inhibitors of the nonmevalonate and the mevalonate pathway of isoprenoid biosynthesis, respectively, on the growth of 34 anaerobic and 10 aerobic prokaryotic strains was studied. Fosmidomycin at the concentrations used was shown to inhibit the growth of 9 (of 10) representatives of the family Microbacteriaceae, 4 (of 5) strains of Thermoanaerobacter, and 11 (of 12) strains of Clostridium, whereas mevinoline inhibited the growth of lactobacilli (Carnobacterium), methanogenic and sulfate-reducing bacteria insensitive to fosmidomycin. During the late growth phase, four strains of actinobacteria (of nine) accumulate the compound, which, upon oxidation, generates a long-lived free radical; three strains synthesize 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEC).

Novel psychrophilic anaerobic spore-forming bacterium from the overcooled water brine in permafrost: description Clostridium algoriphilum sp. nov.

A gram-positive, motile, strict anaerobic spore-forming bacterium was isolated from the over-cooled brine in the permafrost. The optimal temperature for isolate growth was 5-6 degrees C at pH 6.8-7.

Reactivation of the alternative oxidase of Yarrowia lipolytica by nucleoside monophosphates.

The study of the effect of nucleoside phosphates on the activity of cyanide-resistant oxidase in the mitochondria and submitochondrial particles of Yarrowia lipolytica showed that adenosine monophosphate (5'-AMP, AMP) did not stimulate the respiration of intact mitochondria. The incubation of mitochondria at room temperature (25 degrees C) for 3-5 h or their treatment with ultrasound, phospholipase A, and the detergent Triton X-100 at a low temperature inactivated the cyanide-resistant alternative oxidase. The inactivated alternative oxidase could be reactivated with AMP.

[Activation of the alternative oxidase of Yarrowia lipolytica by adenosine 5'-monophosphate].

The study of the effect of nucleoside phosphates on the activity of cyanide-resistant oxidase in the mitochondria and the submitochondrial particles of Yarrowia lipolytica showed that adenosine monophosphate (5'-AMP, AMP) did not stimulate the respiration of the intact mitochondria. The incubation of the mitochondria at room temperature (25 degrees C) for 3-5 h or their treatment with ultrasound, phospholipase A, and detergent Triton X-100 at a low temperature inactivated the cyanide-resistant alternative oxidase. The inactivated alternative oxidase could be reactivated by AMP.

[Analysis of the anaerobic microbial community capable of degrading p-toluene sulphonate].

Three strains of Clostridium sp., 14 (VKM B-2201), 42 (VKM B-2202), and 21 (VKM B-2279), two methanogens, Methanobacterium formicicum MH (VKM B-2198) and Methanosarcina mazei MM (VKM B-2199), and one sulfate-reducing bacterium, Desulfovibrio sp. SR1 (VKM B-2200), were isolated in pure cultures from an anaerobic microbial community capable of degrading p-toluene sulfonate.

[Methanogenic sarcina from an anaerobic microbial community degrading p-toluene sulfonate].

The methanogenic strain MM isolated from an anaerobic microbial community degrading p-toluene sulfonate showed optimal values of temperature and pH for growth equal to 37 degrees C and 6.3-6.9, respectively.

[The alternative oxidase of Yarrowia lipolytica mitochondria is unable to compete with the cytochrome pathway for electrons].

The activity of the cyanide-resistant alternative oxidase (pathway) of Y. lipolytica mitochondria was studied as a function of the activity of the major, cyanide-sensitive, cytochrome pathway. The contribution of the alternative oxidase to the total respiration of mitochondria was evaluated by measuring the rate of oxygen consumption in the presence of cyanide (an inhibitor of the cytochrome pathway).

[Terminal oxidases in different genera of the family Microbacteriaceae].

The nature of terminal oxidases in representatives of four different genera of the family Microbacteriaceae was studied. It was found that the late-logarithmic and early-stationary cells of all of the investigated strains of the genera Plantibacter and Okibacterium contain the aa3-type cytochrome oxidase. Bacteria of the genera Rathayibacter and Agreia synthesize three oxidases, the bb3- and aa3-type cytochrome oxidases and nonheme cyanide-resistant oxidase, in proportions dependent on the cultivation conditions and the growth phase.

Involvement of the alternative oxidase in respiration of Yarrowia lipolytica mitochondria is controlled by the activity of the cytochrome pathway.

The degree of involvement of cyanide-resistant alternative oxidase in the respiration of Yarrowia lipolytica mitochondria was evaluated by comparing the rate of oxygen consumption in the presence of cyanide, which shows the activity of the cyanide-resistant alternative oxidase, and the oxidation rate of cytochrome c by ferricyanide, which shows the activity of the main cytochrome pathway. The oxidation of succinate by mitochondria in the presence of ferricyanide and cyanide was associated with oxygen consumption due to the functioning of the alternative oxidase. The subsequent addition of ADP or FCCP (an uncoupler of oxidative phosphorylation) completely inhibited oxygen consumption by the mitochondria.

[Respiratory activity and naphthoquinone synthesis in the fungus Fusarium decemcellulare exposed to oxidative stress].

The effect of oxidants (hydrogen peroxide and juglone) on the growth, respiration, and naphthoquinone synthesis in the fungus Fusarium decemcellulare was studied. The addition of the oxidants to the exponential-phase fungus inhibited cell respiration (either partially or completely, depending on the oxidant concentration), culture growth, and naphthoquinone synthesis. The treatment of fungal cells with nonlethal concentrations of H2O2 (below 0.

[Level of cyclic AMP during induction of alternative oxidase in Yarrowia lipolytica yeast cells].

The effect of cyanide, antimycin A, ethanol, and acetate on the induction of alternative oxidase in the yeast Yarrowia lipolytica VKM Y-155 sensitive to cyanide, in the presence of the aforementioned compounds led to the development of cyanide-resistant respiration, which could be suppressed by benzohydroxamic acid, an inhibitor of alternative oxidases. The incubation of cells with cyanide, ethanol, or acetate raised the intracellular pool of cAMP, which attained maximal values after a 2- to 3-min incubation, then rapidly decreased to the initial value and did not change over the next three hours of incubation. The possible role of cAMP in the induction of alternative oxidase in yeast cells is discussed.

Desulfotomaculum alkaliphilum sp. nov., a new alkaliphilic, moderately thermophilic, sulfate-reducing bacterium.

A new moderately thermophilic, alkaliphilic, sulfate-reducing, chemolithoheterotrophic bacterium, strain S1T, was isolated from a mixed cow/pig manure with neutral pH. The bacterium is an obligately anaerobic, non-motile, Gram-positive, spore-forming curved rod growing within a pH range of 8.0-9.