RESUMO
Hypoxia is a wide spread phenomena throughout the world's aquatic systems. This paper investigates the functional state of scorpion fish red blood cells under acute hypoxia between 0.57-8.17 mg O2/l (in vitro) by assessing of the fluorescence of Rhodamine 123 (R123) and Fluorescein diacetate (FDA). Acute hypoxia induced a significant increase in the fluorescence of both fluorochromes (R123 - 12-60, FDA - 30-184%). This reaction is based on a probable decrease in erythrocyte membrane permeability. The reduction of functional ionic channels in red blood cells delays FDA in the cytoplasm and lowers the energy costs required for transmembrane cationic gradient maintenance, which reflects an intensification of R123 fluorescence.
Assuntos
Eritroblastos/efeitos dos fármacos , Membrana Eritrocítica/efeitos dos fármacos , Oxigênio/farmacologia , Animais , Hipóxia Celular , Permeabilidade da Membrana Celular , Eritroblastos/citologia , Eritroblastos/metabolismo , Membrana Eritrocítica/metabolismo , Citometria de Fluxo , Fluoresceínas/química , Fluoresceínas/metabolismo , Fluorescência , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Transporte de Íons , Perciformes , Cultura Primária de Células , Rodamina 123/química , Rodamina 123/metabolismoRESUMO
Cyanophages of the family Myoviridae were studied in Lake Hovsgol based on the analysis of g20 gene fragments. The analysis revealed the diversity of g20 cyanomyovirus sequences in Lake Hovsgol. It was found a great similarity of genes from the Lake Hovsgol and Lake Baikal. Distribution of closely related virus strains in these water bodies is attributed to close geographical location, direct water connection and similar hydrochemical parameters of the lakes.
Assuntos
Bacteriófagos/genética , Cianobactérias/virologia , Variação Genética , Myoviridae/genética , Filogenia , Bacteriófagos/classificação , Lagos/microbiologia , Lagos/virologia , Mongólia , Myoviridae/classificação , Análise de Sequência de DNARESUMO
Quintessence, a time-varying energy component that may account for the accelerated expansion of the universe, can be characterized by its equation of state and sound speed. In this paper, we show that if the quintessence density is at least 1% of the critical density at the surface of last scattering the cosmic microwave background anisotropy can distinguish between models whose sound speed is near the speed of light versus near zero, which could be useful in distinguishing competing candidates for dark energy.
RESUMO
Increasing evidence suggests that most of the energy density of the universe consists of a dark energy component with negative pressure that causes the cosmic expansion to accelerate. We address why this component comes to dominate the universe only recently. We present a class of theories based on an evolving scalar field where the explanation is based entirely on internal dynamical properties of the solutions. In the theories we consider, the dynamics causes the scalar field to lock automatically into a negative pressure state at the onset of matter domination such that the present epoch is the earliest possible time consistent with nucleosynthesis restrictions when it can start to dominate.
