Asunto(s)
Antineoplásicos/farmacología , Bacteriófagos/efectos de los fármacos , ADN Viral/metabolismo , ADN/metabolismo , Compuestos de Diazonio/farmacología , Animales , Antineoplásicos/uso terapéutico , Carcinoma de Ehrlich/tratamiento farmacológico , Carcinoma de Ehrlich/metabolismo , ADN de Cadena Simple/metabolismo , Compuestos de Diazonio/uso terapéutico , Técnicas In Vitro , Hígado/efectos de los fármacos , Hígado/metabolismo , Neoplasias Hepáticas Experimentales/tratamiento farmacológico , Neoplasias Hepáticas Experimentales/metabolismo , Ratones , SolucionesAsunto(s)
Carcinoma de Ehrlich/tratamiento farmacológico , ADN de Neoplasias , ADN , Neoplasias Hepáticas Experimentales/análisis , Metilnitrosourea/farmacología , Compuestos de Nitrosourea/farmacología , Conformación de Ácido Nucleico/efectos de los fármacos , Animales , Carcinoma de Ehrlich/metabolismo , Fenómenos Químicos , Química , ADN de Neoplasias/aislamiento & purificación , ADN de Neoplasias/metabolismo , Metilnitrosourea/uso terapéutico , RatonesRESUMEN
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.
Asunto(s)
Transformación Celular Viral , ADN de Neoplasias , ADN , Leucemia L1210/metabolismo , Poliomavirus , Virus 40 de los Simios , Animales , Línea Celular , Cricetinae , ADN/metabolismo , ADN de Neoplasias/metabolismo , Embrión de Mamíferos , Hígado/metabolismo , Metilación , Ratones , Conformación de Ácido Nucleico , RatasAsunto(s)
Pigmentos Retinianos , Rodopsina , Compuestos de Cetrimonio , Digitonina , Calor , Luz , Micelas , Fotólisis , PolietilenglicolesAsunto(s)
ADN de Neoplasias , ADN , Endonucleasas , Conformación de Ácido Nucleico , Animales , Aspergillus oryzae/enzimología , Carcinoma de Ehrlich/análisis , Carcinoma Hepatocelular/análisis , Densitometría , Electroforesis en Gel de Agar , Formaldehído , Concentración de Iones de Hidrógeno , Leucemia L1210/análisis , Hígado/análisis , Neoplasias Hepáticas/análisis , RatonesRESUMEN
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.
Asunto(s)
ADN , Animales , Bovinos , Fenómenos Químicos , Química , Dicroismo Circular , ADN Bacteriano , Metilación , Microscopía Electrónica , Peso Molecular , Conformación de Ácido Nucleico , Polietilenglicoles , Especificidad de la Especie , Streptomyces , TimoRESUMEN
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.