RESUMO
OBJECTIVE: To determine whether cell cycle changes can be detected in myosin II-deficient cells using flow cytometry techniques. BACKGROUND: Although the primary role of myosin II (Myo1p) in the yeast Saccharomyces cerevisiae is in cytokinesis we have reported that this conventional myosin also appears to inuence the regulation of cell wall metabolism as indicated by increases in the expression of chitin metabolizing enzymes in a null mutant of the MYO1 gene. The expression of these enzymes is known to be regulated in the cell cycle suggesting that cell cycle changes may alter their expression. METHODS: Flow cytometry was employed to assess the nuclear DNA content of logarithmic yeast cell cultures as a means of determining changes in the cell cycle of Myo1p-deficient cells. RESULTS: Significant changes were observed in the Myo1p-deficient strain suggesting that these cells are arrested in G2/M-phase of the cell cycle. CONCLUSIONS: Based on the results of this preliminary study, we propose a model in which the increased activity of chitin metabolizing enzymes may be explained by a mitotic arrest in these cells.
Assuntos
Cadeias Pesadas de Miosina/metabolismo , Leveduras/citologia , Leveduras/metabolismo , Técnicas de Cultura de Células , Ciclo Celular , Divisão Celular , Parede Celular/metabolismo , Quitina Sintase/genética , Quitina Sintase/metabolismo , Quitina/metabolismo , Citometria de Fluxo , Expressão Gênica , Haploidia , Mitose , Cadeias Pesadas de Miosina/deficiência , Cadeias Pesadas de Miosina/genética , RNA Mensageiro/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Leveduras/genéticaRESUMO
Serum from patients which tested positive for hepatitis C virus (HCV) by Enzyme Linked Immunosorbent Assay (ELISA) were analyzed for the presence of HCV RNA by nested Polymerase Chain Reaction (PCR) and for anti-HCV antibodies by Recombinant Immunoblot Assay (RIBA II). Total RNA was extracted from whole blood by a new procedure and subjected to reverse transcription of HCV RNA employing primers to the conserved 5' non-coding region of the HCV genome. PCR performed on these samples uncovered several false positive ELISAs. Reciprocal confirmation between PCR and RIBA II results was observed. These results substantiate this variation of the HCV PCR assay as a reliable alternative for routine confirmation of HCV serological tests