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J C Derieux

Publications and source records attributed to J C Derieux.

18 recordsLinked to original sources
PubMed1979

[Effect of 2-ketogluconic acid synthesis on the exopolysaccharide production in a Rhizobium meliloti strain].

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.

Culture Media↗
PubMedDate not supplied

Preparative electroelution of specific protein antigens from Mycoplasma pneumoniae: use in an enzyme-linked immunosorbent assay (ELISA).

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.

Antibodies, Bacterial↗
PubMedDate not supplied

Evidence of an active glucose uptake in Rhizobium meliloti.

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.

Adenosine Triphosphate↗
PubMedDate not supplied

[A study of polysaccharides in fast growing "Rhizobium" (author's transl)].

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.

Cell Division↗
PubMedDate not supplied

[Comparative evaluation of the use of glucose and fructose by the oxidative pathway in a strain of Rhizobium meliloti].

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.

Fructose↗
PubMedDate not supplied

[Demonstration of a metabolic property of Rhibozium meliloti usable for its classification].

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.

Fructose↗