Assuntos
Antineoplásicos/farmacologia , Bacteriófagos/efeitos dos fármacos , DNA Viral/metabolismo , DNA/metabolismo , Compostos de Diazônio/farmacologia , Animais , Antineoplásicos/uso terapêutico , Carcinoma de Ehrlich/tratamento farmacológico , Carcinoma de Ehrlich/metabolismo , DNA de Cadeia Simples/metabolismo , Compostos de Diazônio/uso terapêutico , Técnicas In Vitro , Fígado/efeitos dos fármacos , Fígado/metabolismo , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Neoplasias Hepáticas Experimentais/metabolismo , Camundongos , SoluçõesAssuntos
Carcinoma de Ehrlich/tratamento farmacológico , DNA de Neoplasias , DNA , Neoplasias Hepáticas Experimentais/análise , Metilnitrosoureia/farmacologia , Compostos de Nitrosoureia/farmacologia , Conformação de Ácido Nucleico/efeitos dos fármacos , Animais , Carcinoma de Ehrlich/metabolismo , Fenômenos Químicos , Química , DNA de Neoplasias/isolamento & purificação , DNA de Neoplasias/metabolismo , Metilnitrosoureia/uso terapêutico , CamundongosRESUMO
Using the kinetic formaldehyde method the concentration of secondary structure defects (SSD) in the DNAs of ascite leukosis L 1210 cells and cultures of hamster embryonic cells transformed by virus SV-40 and polyoma was evaluated. It was found that this concentration was considerably higher than in the DNAs from normal liver and primary culture of mouse embryonic cells. The occurrence of the defects in malignant cell DNAs is not due to enzymatic degradation of DNA. Using thin-layer chromatography the content of m5C in the DNAs from 17 sources (transformed cell cultures, experimental tumours and liver cells of mouses with Ehrlich ascite carcinoma) were determined. The methylation level for all these DNAs was higher than for normal mouse and rat liver DNAs. No correlation between the SSD concentration and m5C content in the DNAs studied was observed.
Assuntos
Transformação Celular Viral , DNA de Neoplasias , DNA , Leucemia L1210/metabolismo , Polyomavirus , Vírus 40 dos Símios , Animais , Linhagem Celular , Cricetinae , DNA/metabolismo , DNA de Neoplasias/metabolismo , Embrião de Mamíferos , Fígado/metabolismo , Metilação , Camundongos , Conformação de Ácido Nucleico , RatosAssuntos
DNA de Neoplasias , DNA , Endonucleases , Conformação de Ácido Nucleico , Animais , Aspergillus oryzae/enzimologia , Carcinoma de Ehrlich/análise , Carcinoma Hepatocelular/análise , Densitometria , Eletroforese em Gel de Ágar , Formaldeído , Concentração de Íons de Hidrogênio , Leucemia L1210/análise , Fígado/análise , Neoplasias Hepáticas/análise , CamundongosAssuntos
Pigmentos da Retina , Rodopsina , Compostos de Cetrimônio , Digitonina , Temperatura Alta , Luz , Micelas , Fotólise , PolietilenoglicóisRESUMO
Some peculiarities of compactization of double-stranded DNA molecules containing methylated nitrogen bases have been studied in water-salt solutions of PEG. It is shown that the methylation of N7-atoms of guanyl residues in original DNA molecules does not prevent the formation of DNA compact particles, but results in a decrease of the amplitude of the negative band in the CD spectrum of compact particles. The influence of N7-guanine methylation on the shape of the CD spectrum being the greater, the lower is the concentration of PEG. The dependence of the negative band amplitude in the CD spectrum on the content of methylated guanyl residues is practically the same for low-molecular weight DNA's from different sources. The observed decrease in the negative band amplitude is interpreted as a result of alterration of guanyl residue orientation relative to the helix axis which leads to diminished optical activity of the "microcrystalline" domains of compact particles. The evidence obtained suggests that changes in the secondary structure of DNA lead to considerable difference between CD spectra of compact particles of methlated DNA and psi-form of DNA. (The changes in the CD spectrum of the DNA compact particles occur also as a result of methylation of C5-atoms of cytosine residues). It is suggested that the negative band in the CD spectrum can be used a criterion for detection of negligible alterations in the DNA secondary structure.
Assuntos
DNA , Animais , Bovinos , Fenômenos Químicos , Química , Dicroísmo Circular , DNA Bacteriano , Metilação , Microscopia Eletrônica , Peso Molecular , Conformação de Ácido Nucleico , Polietilenoglicóis , Especificidade da Espécie , Streptomyces , TimoRESUMO
It has been demonstrated that UV irradiation of acetaldehyde (2.5%) and ammonium nitrate (1.5%) solutions results in the synthesis of the pyruvic acid (PA). With the increase in the duration of irradiation, the yield of the produced PA decreases which is associated both with its photolysis and with its further transformations, for instance, into amino acids. The results obtained are discussed in relation to abiogenic synthesis of biologically important compounds in prebiological evolution and to possible development of metabolic pathways which are found in contemporary organisms.