Assuntos
Membranas Intracelulares/metabolismo , Fluidez de Membrana , Mitocôndrias Hepáticas/metabolismo , NAD/metabolismo , Animais , Antioxidantes/farmacologia , Membranas Intracelulares/efeitos dos fármacos , Cinética , Masculino , Fluidez de Membrana/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Oxirredução , RatosAssuntos
Anti-Helmínticos/farmacologia , Fosfolipases A/metabolismo , Fosfolipases/metabolismo , Animais , Abelhas/enzimologia , Avaliação Pré-Clínica de Medicamentos , Helmintos/enzimologia , Hidrólise , Cinética , Fosfolipases A/antagonistas & inibidores , Fosfolipases A2 , Fosfolipídeos/metabolismoRESUMO
Escherichia coli cells were cultivated in a medium containing 1-pyrene butanoic acid, a fluorescent probe. Total lipids were extracted from the cells, and the extract was separated by thin-layer chromatography. The fluorescent fractions were examined using spectrofluorimetry. The starting 1-pyrene butanoic acid was shown to be biosynthetically incorporated into the bacterial lipid. Four fluorescent fractions appeared as a result; the fractions were derivatives of this compound modified in the chromophore and the fatty acid chain. The results indicate that the formation of 1-pyrene butanoic acid fluorescent metabolites can be used for studying the oxidation-reduction systems of the bacterium.
Assuntos
Escherichia coli/metabolismo , Ácidos Graxos/biossíntese , Membrana Celular/metabolismo , Cromatografia em Camada Fina , Corantes Fluorescentes/metabolismo , Pirenos/metabolismo , Espectrometria de FluorescênciaRESUMO
The effect of purified SV40 T antigen on DNA synthesis in isolated nuclei from the confluent culture of CV-1 cells was studied. In the presence of T antigen the incorporation of [3H]TTP into DNA was found to be 2 to 3 times as high as in the control nuclei. The resulting labelled DNA was subjected to alkaline sucrose gradient centrifugation, which revealed the presence of 4S DNA species, corresponding to Okazaki fragments of animal cells. The latter finding suggests a replicative mode of DNA synthesis induced by T antigen. T antigen isolated from the cells infected with SV40 tsA-mutant and kept at a nonpermissive (41 degrees) temperature fails to stimulate DNA synthesis in isolated nuclei from resting cells. On storage at 4 degrees SV40 T antigen gradually loses its ability to stimulate DNA synthesis and by the 8th day even suppresses it when tested on isolated nuclei from a growing cell culture. No effect of T antigen on the endonuclease-induced reparative synthesis of DNA could be observed. The data described suggest that T antigen is directly involved in the control of DNA synthesis in the cells infected or transformed with SV40.
