RESUMO
The review considers main approaches to solving the problem in the quantification of melatonin and describes physicochemical and biological methods for melatonin determination in biological fluids (saliva, urine, plasma) and tissues. The impetus to writing this paper came from the considerably growing interest of the scientific community in melatonin and the in-depth studies of its physiological role, which had revealed a diversity of its previously unknown most important functions and confirmed its presence in many compartments of the body. Due to the specificity of its molecular structure and low concentration, melatonin remains invisible for many conventional analyses. The way out may be combination detection that involves the benefits of a few procedures and that has emerged at the interface of various sciences.
Assuntos
Melatonina/análise , Líquidos Corporais/química , Cromatografia Líquida de Alta Pressão , Humanos , Técnicas Imunoenzimáticas/métodos , Espectroscopia de Ressonância Magnética/métodos , Espectrometria de Massas/métodos , Melatonina/sangue , Melatonina/urina , Radioimunoensaio , Saliva/químicaRESUMO
The Escherichia coli K12 mutant having the increased efficiency for plasmid DNA transformation has been shown to possess the different protein composition of the outer membrane of the cellular wall, as compared with that of the wild type strain. Correlation between the level of calcium-dependent plasmid transformation and the portion of infections DNA bound with cytoplasmic membranes is demonstrated for the Escherichia coli cells mutant for outer membrane structure and ability to be transformed by plasmid DNA.
Assuntos
Proteínas da Membrana Bacteriana Externa/genética , Permeabilidade da Membrana Celular , DNA Bacteriano/genética , Escherichia coli/genética , Plasmídeos , DNA Bacteriano/metabolismo , Escherichia coli/metabolismo , Mutação , Transformação BacterianaRESUMO
The level of plasmid transformation and transfection by the high molecular mass DNA was studied for Escherichia coli mutants having increased efficiency of plasmid transformation by low molecular mass DNA. Decreased level of plasmid transformation and transfection registered in some mutants as compared to the one in wild type strain suggests the specificity of Escherichia coli cells penetration for DNA of different molecular mass.
Assuntos
DNA Bacteriano/genética , Escherichia coli/genética , Plasmídeos , Transformação Bacteriana , Peso Molecular , MutaçãoRESUMO
The dependence of competence of Escherichia coli cells in transfection and plasmid transformation from phage lambda receptor protein was studied. Mal+ variants, sensitive to phage lambda (Mal+ lambda S) were obtained from strains with impaired lambda-phage receptor protein (Mal-lambda R). Maximum increase of transfection (4.7-fold) was observed in JC411Mal+ lambda S strain. The efficiency of plasmid transformation of pMB9 and RP4 DNAs was also higher in the strain with functioning lambda-receptor protein.
Assuntos
Bacteriófago lambda/genética , Escherichia coli/genética , Plasmídeos , Receptores Virais/fisiologia , Mapeamento Cromossômico , Escherichia coli/metabolismo , Regulação da Expressão Gênica , Maltose/metabolismo , Receptores Virais/genética , Transfecção , Transformação GenéticaRESUMO
Escherichia coli K-12 mutants with an enhanced efficiency of plasmid transformation were obtained. In all the mutants, the efficiency of transfection with lambda vir phage DNA was changed, in comparison to the parent strain. However, these changes did not always correlate strictly with plasmid transformation alterations. For instance, two mutants with an increased plasmid transformation efficiency demonstrated 50-fold decrease in the level of transfection with lambda phage DNA. Polyacrylamide gel electrophoresis points to both quantitative and qualitative differences in protein composition of the mutant cell envelopes, as compared with the parent strain.
Assuntos
Escherichia coli/genética , Mutação , Plasmídeos , Transformação Bacteriana , Proteínas de Bactérias/análise , Proteínas de Bactérias/genética , Bacteriófago lambda/genética , DNA Viral/genética , Eletroforese em Gel de Poliacrilamida , Proteínas de Membrana/análise , Proteínas de Membrana/genética , TransfecçãoRESUMO
The study of the plasmid transformation of E. coli K-12, carried out in mutants with the known damages in the main proteins of the outer membrane, made it possible to reveal the essential role of OmpA protein in this process. The damage of lipoprotein led to a considerable increase in the level of plasmid transformation. The mutants with the enhanced efficiency of plasmid transformation, obtained by the authors, were not connected with lesions in the main proteins of the outer membrane: OmpF, OmpC and OmpA.
Assuntos
Proteínas de Bactérias/genética , DNA Bacteriano/genética , Proteínas de Membrana/genética , Mutação , Plasmídeos , Transformação Bacteriana , Proteínas da Membrana Bacteriana ExternaRESUMO
The action of tetracaine hydrochloride, a local anesthetic, on the effectiveness of plasmid transformation and transfection in variants of E. coli K-12 has been studied. The concentrations of tetracaine hydrochloride used in the experiment (0.002 M) affect the level of the synthesis of most proteins in the outer membrane of these bacteria. This seems to be one of the causes of changes in the effectiveness of plasmid transformation and transfection in E. coli K-12.
Assuntos
Anestésicos Locais/farmacologia , Escherichia coli/efeitos dos fármacos , Plasmídeos/efeitos dos fármacos , Tetracaína/farmacologia , Transfecção/efeitos dos fármacos , Transformação Bacteriana/efeitos dos fármacos , Proteínas da Membrana Bacteriana Externa/biossíntese , Bacteriófago lambda/efeitos dos fármacos , Bacteriófago lambda/genética , Membrana Celular/efeitos dos fármacos , DNA Bacteriano/genética , Escherichia coli/genética , MutaçãoAssuntos
Escherichia coli , Mutação , Nucleosídeos/metabolismo , Conjugação Genética , Citidina Desaminase/metabolismo , Escherichia coli/enzimologia , Escherichia coli/metabolismo , Genes Reguladores , Fosfotransferases/metabolismo , Purina-Núcleosídeo Fosforilase/metabolismo , Timidina Fosforilase/metabolismo , Uridina Fosforilase/metabolismoRESUMO
A new rapid method for plasmid transformation of Escherichia coli K-12 cells has been devised. It consists in application of plasmid pMB9 DNA to the surface of an agar medium with 0.05 M CaCl2 and tetracycline (50 micrograms/ml). The recipient cells treated with nitrosoguanidine were drifted on by sectors on the plates with pMB9 DNA. The method enabled the obtaining of 12 mutants with high efficiency of plasmid transformation.