PubMed Health⌕ Search

Biomedical subjects

M Véron

Publications and source records attributed to M Véron.

At least 109 records · Page 6Linked to original sources
PubMed1975

The threonine-sensitive homoserine dehydrogenase and aspartokinase activities of Escherichia coli K12. Specific inactivation of the homoserine dehydrogenase activity by the affinity label, 2-amino-4-oxo-5-chloropentanoic acid.

2-Amino-4-oxo-5-chloropentanoic acid inactivates specifically the homoserine dehydrogenase activity of the bifunctional enzyme, aspartokinase I--homoserine dehydrogenase I. The aspartokinase activity remains essentially untouched and retains its threonine sensitivity. The inactivation of the dehydrogenase requires the covalent binding of one equivalent of the analogue per subunit. Alkylation does not affect the tetrameric state of the protein. The alkylating agent, a substrate analogue, meets the qualitative and quantitative requirements of an affinity label.

Alcohol Oxidoreductases↗
PubMed1975

[Nutrition and taxonomy of "Enterobacteriaceae" and related bacteria. I. Technical procedure for auxanograms (author's transl)].

Study of nutritional capacities of 186 strains of Enterobacteriaceae or related bacteria has been undertaken for a taxonomic purpose. In this paper, the auxanographic method is described and discussed. Unlike other techniques in which the medium is supplemented by each substrate, at fixed concentration, the method described here consists in achieving diffusion of the 146 substrates tested as sole source of carbon and energy, in a medium without other energetic substrate. The results of these tests will be described in a further paper.

Culture Media↗
PubMed1975

[Nutrition and taxonomy of "enterobacteriaceae" and related bacteria. II. General results and classification (author's transl)].

A study of 186 strains belonging to eleven genera of the family Enterobacteriaceae and to three genera of the family Vibrionaceae has been carried out in order to determine their "versatility" towards 146 organic substrates tested as sole source of carbon and energy. Glucose was the only substrate used by all the strains; gluconate and glycerol were used by respectively 184 and 185 strains; 55 substrates were used by no one strains. The 90 substrates which were used by a fraction of the strains have served to establish a numerical classification of our strains, exclusively relied on these nutritional characters. In using the distinctness coefficient, it was possible to cut the dendrogram into 32 "classes" which may be clustered into 7 "groups" or 2 "sets": the obtained taxa are approximatively similar to the ones which are actually described on the basis of morphological and biochemical characters. The studied strains use 32.7 +/- 11.1 substrates on an average: the "eutrophic Klebsielleae group", which is the most versatile, uses 49.5 substrates on an average, and the "Shigella group", the lease versatile one, only uses 16.5 substrates on an average. The strains of the set 1 (100 strains) use 39.0 substrates on an average: all they belong to the family Enterobacteriaceae. The strains of the set 2 (86 strains) use 25.8 substrates on an average: they belong either to the family of Vibrionaceae, either to any little versatile genus of Enterobacteriaceae, namely Shigella, Proteus and Edwardsiella. The taxonomic inferences of this classification, exclusively established by means of the nutritional characters, are discussed.

Alcohols↗
PubMed1975

[Nutrition and taxonomy of "enterobacteriaceae" and related bacteria. III. Nutritional characters and differentiation of the taxonomic groups (author's transl)].

A batch of 186 strains belonging to the families Enterobacteriaceae or Vibrionaceae has been studied by determination, for each strain, of the "versatility" towards 146 organic substrates tested as sole source of carbon and energy. This study allowed to work out a classification of these strains into the 32 classes which have been previously described. In the present paper the nutritional characters of these classes are reported. On the basis of these characters, the 32 classes may be regrouped into 7 groups, namely: (1.1) "Escherichia-Salmonella-Citrobacter", (1.2) "dystrophic Klebsielleae", (1.3) "eutrophic Klebsielleae", (2.1) "Shigella", (2.2) "Proteus", (2.3) "Aeromonas-Vibrio", (2.4) "Edwardsiella tarda-Aeromonas salmonicida-Plesiomonas shigelloides". Only 4 strains (about 2 percent) happened misclassified in this study where the taxa were assembled exclusively by means of nutritional characters. The number and the type of the substrates which can be used in each group are reported, as well as the nutritional characters which are possibly useful to differential diagnosis. The taxonomic considerations which may be deduced from this study are discussed.

Amino Acids↗
PubMedDate not supplied

[Determination of biovars of Brucella melitensis by manometric character: epidemiological value and relation to serovars].

As Brucella melitensis is the most frequently encountered Brucella species in human medicine, and as its subdivision into three serovars is insufficient for epidemiological studies, we sought to define a new scheme for biotyping of this species. For this purpose, we studied 94 strains for their oxidative metabolic rates on 32 substrates and their susceptibility to ten antibiotics, and 132 strains for their activities with three enzymes. A taxonomic study on the basis of the 32 oxidative metabolic rates led to the distinction of five biovars which could then be defined by means of the five most discriminating substrates. Among the ten antibiotics tested, only three showed varying patterns of susceptibility. Oxidative metabolic rates were not correlated with these patterns of susceptibility nor with the enzymatic activities. However, a relationship was found between biovar and serovar, especially with regard to the following substrates: meso-erythritol, deoxythymidine, D-galactose and DL-phenylalanine. As shown by correspondence analysis, the repartition of biovars significantly differed among French administrative regions.

Anti-Bacterial Agents↗
PubMedDate not supplied

Non-specific resistance of mice to bacteria, induced by an acellular extract from Pseudomonas aeruginosa.

Antibacterial activity of an acellular extract from Pseudomonas aeruginosa (AEP) was assessed in mice infected with bacteria including extracellular and intracellular bacteria. It was shown that AEP strongly increased resistance of mice to bacterial infections. The protective effect was maximal between days 2 and 5 after inoculation of AEP, and subcutaneous inoculation was most efficient. The ED90 of AEP was about 30 micrograms per mouse (i.e. about 10 times less than that of Corynebacterium parvum). AEP caused an increased in Listeria monocytogenes destruction in the spleen and liver. AEP-treated mice exhibited an early recruitment of phagocytes after bacterial challenge in the peritoneal cavity. Furthermore, phagocytosis and O2-dependent bactericidal systems were studied by measuring the chemiluminescence response from macrophages under exposure to L. monocytogenes and Staphylococcus aureus: the response was earlier and higher from AEP-stimulated macrophages than from controls. It was concluded that AEP induces an early recruitment of phagocytes and increases their bactericidal activity.

Adjuvants, Immunologic↗