RESUMO
Cells from anti-HIV-positive persons were used in experiments for virus isolation. The RT-activity, viral antigen, nucleic acids, electron microscopic morphology, and infectivity were studied. The data presented allow a conclusion that the virus was isolated. These data confirmed the previous diagnosis of HIV infection.
Assuntos
Antígenos HIV/sangue , Soropositividade para HIV/imunologia , HIV-1/imunologia , Linfócitos/imunologia , Northern Blotting , Southern Blotting , Linhagem Celular , Células Cultivadas/imunologia , Células Cultivadas/microbiologia , DNA Viral/genética , Soropositividade para HIV/microbiologia , HIV-1/genética , HIV-1/ultraestrutura , Humanos , Linfócitos/microbiologia , Microscopia Eletrônica , Hibridização de Ácido Nucleico , RNA Viral/genética , DNA Polimerase Dirigida por RNA/análise , Vírion/ultraestruturaRESUMO
The recombinant plasmids containing autonomously replicating sequence (ARS) of yeast rDNA repeat are characterized by a high instability in transformed yeast cells. The instability of chimaric plasmids in yeast may result from improper replication and/or irregular mitotic segregation. To study the replication properties alone we have constructed series of hybrid plasmids containing centromeric DNA (CEN3), a selective marker (leu2) and ARS of rDNA. Each of these plasmids with the functional centromere should exhibit chromosomal i. e. regular type of mitotic segregation. The study of mitotic segregation of constructed plasmids has shown that the ARS rDNA from yeast is distinguished from other ARSs described in literature: ARS1, ARS2, ARS o-micron DNA. 1. The activation of replication of ARS rDNA is accidental, i. e. probability of ARS rDNA in the cell cycle is much less than one. 2. Some nuclear mutations as well as rho- mutation result in the increase of replicative activity of ARS rDNA. In some yeast strains the activity of ARS rDNA can reach the activity of ARS1, i. e. was close to one. The features of ARS rDNA may account for the phenomenon of amplification of rDNA genes.
Assuntos
Replicação do DNA , DNA/genética , Plasmídeos , Saccharomyces cerevisiae/genética , DNA Fúngico/genética , DNA Recombinante/metabolismo , DNA Ribossômico , Amplificação de Genes , MutaçãoRESUMO
In Saccharomyces yeast the significant portion of rRNA genes may be located as extrachromosomal copies. Extrachromosomal rDNA is represented by covalently-closed circular molecules with a major class contour length of 3.3 micrometer (the same as the length of one rDNA repeating unit). Covalently-closed circular rDNA can only be isolated from the stationary phase yeast culture (more than 60 hours of growth). Electron microscopy revealed several discrete length classes of circular molecules. Three of them are 3.3, 6.6 and 9.9 micrometers. Circular molecules were found with contour length less than 3.3 micrometers (1.1, 2.0 and 2.6 micrometers). The proportion of these molecules is 8% from the total number.
