RESUMEN
A rapid, simple and preparative method is described for the recovery of the seven highest molecular weight proteins (HMWP) from Mycoplasma pneumoniae membrane. The yield of proteins obtained was approximately 90%. The method involved the separation of M. pneumoniae proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), followed by electroelution of HMWP. These eluted antigens were used in an ELISA to measure IgG antibodies in sera from 9 blood donors and 9 patients with M. pneumoniae infection. The specificity of M. pneumoniae HMWP was examined by competition ELISA and immunoblotting with different mycoplasma species encountered in the respiratory tract.
Asunto(s)
Anticuerpos Antibacterianos/análisis , Antígenos Bacterianos/aislamiento & purificación , Ensayo de Inmunoadsorción Enzimática , Mycoplasma pneumoniae/inmunología , Neumonía por Mycoplasma/inmunología , Antígenos Bacterianos/inmunología , Membrana Celular/inmunología , Pruebas de Fijación del Complemento , Electroforesis , Electroforesis en Gel de Poliacrilamida , Humanos , Immunoblotting , Inmunoglobulina G/análisis , Peso MolecularRESUMEN
Rhizobium meliloti M5N1 showed immediate uptake of glucose. Glucose accumulation was a saturable function of the glucose concentration, and km and Vmax values for uptake were determined. The glucose uptake system was found to be proteic with a turnover of about 6 h. This system was observed to be an active ATP-dependent process, since it was severely inhibited by uncouplers. Glucose analogues and others hexoses had some inhibitory effects on glucose uptake, but not polyols and lactose.
Asunto(s)
Glucosa/metabolismo , Rhizobium/metabolismo , Adenosina Trifosfato/metabolismo , Unión Competitiva , Transporte Biológico Activo/efectos de los fármacos , Metabolismo de los Hidratos de Carbono , Proteínas Portadoras/metabolismo , Medios de Cultivo , Cinética , Proteínas de Transporte de Monosacáridos , Rhizobium/crecimiento & desarrolloRESUMEN
Fast-growing Rhizobium and Agrobacterium strans were studied for their behaviour towards two carbohydrates (glucose and fructose) according to the following criteria: acidification and soluble exopolysaccharide production by resting cells. R. meliloti and Agrobacterium spp. showed a similar behaviour: in glucose-containing medium, acidification occurred and few exopolysaccharides were produced, whereas in medium supplemented with fructose, a neutral pH was maintained and large amounts of exopolysaccharides were synthesized. Other fast-growing Rhizobium spp. did not acidify these media and produced variable amounts of exopolysacchrides.
Asunto(s)
Rhizobium/metabolismo , Fructosa/metabolismo , Glucosa/metabolismo , Polisacáridos Bacterianos/metabolismo , Rhizobium/clasificaciónRESUMEN
The oxidation rate in resting cells of Rhizobium meliloti was investigated with either glucose or fructose as substrate. Fructose uptake was found to be complete, whereas glucose uptake did not fully occur, yielding 2-kitogluconic acid in the medium. At the end of fructose oxidation, significant levels of this substrate and its derivatives had accumulated in the bacteria.
Asunto(s)
Fructosa/metabolismo , Glucosa/metabolismo , Rhizobium/metabolismo , Oxidación-ReducciónRESUMEN
Two categories of carbon substrates are defined for Rhizobium meliloti: the first favours the synthesis of exopolysaccharides (fructose belongs to this category) while the other is not suitable (glucose belongs to this category). With fructose, resting cells synthesize polysaccharides during more than 100 h and this synthesis is at its best in aerobic conditions at 30 degrees C. With glucose, 2-ketogluconic acid accumulates and rapidly stops the synthesis. The method used to stop this acidification allows with glucose a synthesis which can be compared to the one obtained with fructose.
Asunto(s)
Gluconatos/biosíntesis , Polisacáridos Bacterianos/biosíntesis , Rhizobium/metabolismo , Microbiología del Suelo , Medios de Cultivo , Fructosa/metabolismo , Glucosa/metabolismo , Concentración de Iones de Hidrógeno , Medicago sativa/microbiología , Rhizobium/crecimiento & desarrollo , TemperaturaRESUMEN
Rhizobium meliloti can produce many polysaccharides on D-fructose and D-mannitol. In glucose-grown cultures, few polysaccharides are observed and 2 keto-gluconate is accumulated.
Asunto(s)
Fructosa/metabolismo , Glucosa/metabolismo , Rhizobium/metabolismo , Concentración de Iones de Hidrógeno , Manitol/metabolismo , Polisacáridos Bacterianos/biosíntesisRESUMEN
This work is an attempt to use the composition of exopolysaccharides in the Rhizobium genus as a criterium of taxonomic importance. The organisms were first cultured in media and under conditions which led to the production of as many polysaccharides as possible. The medium chosen for proliferation conditions was Wright's medium; for conditions of non-proliferation conditions was Wright's medium; for conditions of non-proliferation, a minimal medium without nitrogen was used. The polysaccharides synthesised in Wright's medium consists in neutral sugars such as glucose, galactose, mannose and sometimes rhamnose and in uronic acid in various quantities. If no mannose is found in the polysaccharides when they are synthesised in non-proliferation conditions and if mannans are found in yeast broth, it may be thought, as suggested by Humphrey, that mannose would come from those mannans. The study of the composition of these polysaccharides enables us to sort out two groups of fast growing Rhizobium. The first one, relatively uniform, corresponds to the strains of R. leguminosarum, trifolii and phaseoli. In these strains, the polysaccharides are made of about 70% of neutral sugars and 20% of glucuronic acid.