Assuntos
Algoritmos , Alelos , Fenótipo , Plantas/genética , Software , Biblioteca Gênica , Variação GenéticaRESUMO
Two hundred and fifty seven human clinical Pseudomonas aeruginosa strains isolated between 1984 and 1990 in several regions of France, as well as two reference strains, were studied by computer-assisted statistical analysis of the data from their esterase electrophoretic patterns and rrn restriction fragment length polymorphisms. No correlation was found between the two sets of data except for some strains of serotype O12 which, thus, may constitute a distinct group within the species. This absence of correlation indicates a high gene flow rate within human isolates of the P. aeruginosa species. A possible explanation is that, because of an as yet unidentified selective advantage, the esterase loci are a major target for recombinational events. Alternatively, horizontal genetic transfers between strains may have occurred at so high a rate that the clonal structure usually observed in bacterial populations has been disrupted. This study highlights clearly the need for caution in inferring bacterial population structure from any single class of genetic markers.
Assuntos
Esterases/genética , Isoenzimas/genética , Polimorfismo de Fragmento de Restrição , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/classificação , França/epidemiologia , Genes Bacterianos/genética , Infecções por Pseudomonas/epidemiologia , Pseudomonas aeruginosa/enzimologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Fatores de TempoRESUMO
Genomic DNA of 191 strains of the family Pseudomonadaceae, including 187 strains of the genus Xanthomonas, was cleaved by EcoRI endonuclease. After hybridization of Southern transfer blots with 2-acetylamino-fluorene-labelled Escherichia coli 16+23S rRNA probe, 27 different patterns were obtained. The strains are clearly distinguishable at the genus, species, and pathovar levels. The variability of the rRNA gene restriction patterns was determined for four pathovars of Xanthomonas campestris species. The 16 strains of X. campestris pv. begoniae analyzed gave only one pattern. The variability of rRNA gene restriction patterns of X. campestris pv. manihotis strains could be related to ecotypes. In contrast, the variability of patterns observed for X. campestris pv. malvacearum was not correlated with pathogenicity or with the geographical origins of the strains. The highest degree of variability of DNA fingerprints was observed within X. campestris pv. dieffenbachiae, which is pathogenic to several hosts of the Araceae family. In this case, variability was related to both host plant and pathogenicity.
RESUMO
The intra- and inter-species differentiation of 90 strains of Yersinia belonging to six species were studied independently by computer-assisted statistical analysis of data from enzyme electrophoretic polymorphism and ribosomal DNA (rDNA) restriction fragment length polymorphism. Two correspondence analyses (CA) demonstrated the concordance between the bacterial classification obtained from enzymatic and genomic data. This concordance was reinforced by an algorithm of the correspondence established between the two dendrograms drawn from previous computations. Comparison of CA with similarity analysis (also called "numerical taxonomy") indicated that the intra- and inter-species differentiation obtained by the two methods are similar. The advantage of CA is that it gives a synthetic geometrical representation of the results (factorial planes), displaying both the main features of the clusters of strains (location and dispersion) and their essential character (i.e.: enzyme electrophoretic variant, rDNA fragment size).
Assuntos
Computadores , DNA Bacteriano/química , DNA Ribossômico/química , Eletroforese em Gel de Poliacrilamida , Enzimas/química , Polimorfismo de Fragmento de Restrição , Yersinia/classificação , Algoritmos , Desoxirribonuclease EcoRI , Desoxirribonuclease HindIII , Yersinia/enzimologia , Yersinia/genéticaRESUMO
A computer-assisted statistical treatment of the electrophoretic data obtained from the analysis of two dehydrogenases and 27 kinds of esterases produced by strains belonging to the taxonomically complex genus Acinetobacter is described. The 12 genospecies were clearly separated from each other by correspondence analysis. For each genospecies the distances of the strains from their barycenter were computed and typical isolates suitable for use as reference strains were determined. This approach is suitable for the systematic study of other procaryotic or eucaryotic organisms.
Assuntos
Acinetobacter/isolamento & purificação , Processamento Eletrônico de Dados , Eletroforese/métodos , Acinetobacter/enzimologia , Esterases/análise , Estatística como AssuntoRESUMO
We describe a method of micro-assay of serum iron by atomic absorption without flame, after deproteinisation of the serum by molar hydrochloric acid. In this way, we can assay the serum iron in 10 microliters of serum by injection of the supernatant into a graphite oven. The results show a good correlation with those obtained by conventional techniques of atomic absorption and colorimetric assays using ferrozine and bathophenanthroline. However, great care must be taken in the cleaning of plastic test tubes.
Assuntos
Ferro/sangue , Proteínas Sanguíneas/isolamento & purificação , Hemoglobinas/isolamento & purificação , Humanos , Espectrofotometria Atômica/instrumentação , Espectrofotometria Atômica/métodosRESUMO
A rapid method for the determination of urinary oxalic acid by gas-liquid chromatography is described. The procedure involves extraction of oxalate from urine by tetrahydrofuran followed by evaporation to dryness and subsequent with diesterification with the boron-trifluoride propanol. The derivative is extracted with hexane and is detected by FID gas chromatography. Malonic acid is used as internal standard. Analytical recovery ranged from 94 to 105%. The coefficient of variation in replicate aliquots over the entire range is less than 6%. The expected range for our method is calculated to be 44 to 577 mumol of oxalate per 24-h urine.
Assuntos
Oxalatos/urina , Cromatografia Gasosa , Ionização de Chama , Humanos , Valores de ReferênciaRESUMO
Ten organic acids are extracted from urine. Two extraction methods are used: anion exchange on DEAE-Sephadex columns and organic solvent extraction with five different solvents: diethyl ether, ethyl acetate, isopropyl chloride, light petroleum, and tetrahydrofuran. In order to quantify the extractions, the corresponding 14C-labeled acids are added to standard acid solutions and extraction rates are measured by a liquid scintillation counting system. The results show that: (1) The efficiency of anion exchange is generally good for all tested acids. (2) The extraction efficiency is not identical for the different solvents, one solvent being more efficient for a certain acid than another: tetrahydrofuran, which is generally a good solvent, is too hygroscopic to be usable. Isopropyl chloride and light petroleum are too specific with the most apolar molecules. Ethyl acetate and diethyl ether are similar and usable because of their acceptable solubilisation power as to the most polar molecules, their good solubilisation reproducibility and their readiness of use. (3) The solvent extraction method is not as time-consuming as the anion-exchange method which generally requires lengthy elution and extraction.