RESUMO
Reactive oxygen species are toxic and cancerogenic factors to living organisms. They are suggested to cause DNA damage (modification) that triggers cancer development. It seems that oxidative damage product 8-oxo-deoxyguanosine (8-oxo-dG) which induces transversion of G to T could be a good chemical marker for cancerogenesis. The aim of our studies was to use 8-oxo-dG as a probe for brain tumour in 17 patients operated on for intracranial neoplasm. Among the patients there were 7 female and 11 male aged from 14 to 60 year. Mean age was 42.88 +/- 16.14 yrs. Several types of tumours were selected histopathologically: from neuroepithelial tissue--6 cases, meningeomas--4, metastases--3, lymphomas--2, neurinoma--1 and chondrosarcoma--1. The tumour tissue was collected from removed material and stored at -20 degrees C. DNA from the neoplastic tissues was isolated by salt method. After hydrolysis of DNA with nuclease P1 and dephosphorylation with bacterial alkaline phosphatase, the mixture of nucleosides was analysed by liquid chromatography method connected with electrochemical detector (HPLC-ECD) working at potential 400 mV. We found higher level of 8-oxo-dG in DNA of patients with malignant tumour (glioblastoma). However, at the present stage of these studies there was no proportional correlation between the level of 8-oxo-dG in DNA in tumour tissue and its malignancy.
Assuntos
Adjuvantes Imunológicos/farmacocinética , Biomarcadores Tumorais/fisiologia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/metabolismo , Guanosina/análogos & derivados , Adolescente , Adulto , Cromatografia Líquida de Alta Pressão , DNA/metabolismo , Feminino , Guanosina/farmacocinética , Humanos , Hidrólise , Masculino , Espécies Reativas de Oxigênio/metabolismoRESUMO
During isolation of total ribonucleic acids from white lupin (Lupinus albus) and their subsequent separation by 10% polyacrylamide gel electrophoresis, a fast migrating RNA band is very well separated. The nucleotide sequence analysis of 76 nucleotide long sequence with many modified nucleosides was found to be identical with that of tyrosine specific tRNA of yellow lupin seeds (Lupinus luteus) and wheat germ (Triticum aestivum). Also this tRNA(Tyr) is identical with plant amber suppressor tRNA. The presented approach offers a very rapid method of purification of plant tRNA with UAG suppressor activity.
Assuntos
Fabaceae/genética , Plantas Medicinais , RNA de Transferência de Tirosina/isolamento & purificação , Sequência de Bases , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Homologia de Sequência , Fatores de TempoRESUMO
It has been found that the bacterial endotoxins (lipopolysaccharides, LPSs) contain some amino acids and glycine is the most abundant amino acid in the polysaccharide core preparations of LPSs of gram-negative bacteria. Until now nothing was known about the mechanism of amino acid incorporation into the lipopolysaccharide core. We found that one out of three glycyl-tRNAs(Gly) from Escherichia coli is the donor of amino acid and is the substrate for a putative aminoacyl-tRNA:LPS transferase. We have isolated, purified this tRNA and determined its nucleotide sequence to be major E.coli tRNA(3Gly). This tRNA(Gly) (anticodon GCC) conserved the tRNA structural features. The assay for determination of the specific incorporation of glycine into the lipopolysaccharide was also invented and described.
