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J Courtois

Publications and source records attributed to J Courtois.

At least 55 records · Page 3Linked to original sources
PubMed1993

Structural characterization and rheological properties of an extracellular glucuronan produced by a Rhizobium meliloti M5N1 mutant strain.

The mutant strain M5N1 C.S. (NCIMB 40472) of Rhizobium meliloti M5N1 is able to produce during fermentation a partially acetylated extracellular (1-->4)-beta-D-glucuronan. At low concentration (1 g.l-1), in the presence of monovalent cations, this new glucuronate behaves as a thickening agent, whereas at higher concentration a thermoreversible gel is obtained. With such divalent cations as Ca2+, a thermally stable gel can be formed.

Carbohydrate Sequence↗
PubMed1991

Cloning and expression in Escherichia coli of dextranase genes from Bacteroides thetaiotaomicron.

A genomic bank was constructed in Escherichia coli HB101, consisting of DNA fragments from Bacteroides thetaiotaomicron strain 489 inserted within the vector pBR322. By screening on complex medium containing blue dextran, 10 stable dextranase-positive (Dex+) clones were isolated. Seven groups of Dex+ inserts were identified on the basis of their restriction maps and hybridization responses. Dextanase activity of the recombinant clones was weak, and was revealed on the selection medium after 15 days. Subcloning of a Sau3AI partially digested 3.2-kb insert in the expression vector pDR720 greatly enhanced dextranse activity on blue dextran plates in one clone, but the delay remained unaltered. This suggested that the enzyme was released by cell lysis. Expression of this 0.7-kb subcloned insert was dependent on the promoter region of tryptophan operon carried by pDR720.

Bacteroides↗
PubMed1988

High-frequency transformation of Rhizobium meliloti.

Transformation of R factor RP4 and its derivative pRK290 from Escherichia coli to Rhizobium meliloti is reported. The efficiency of transformation was in the range of 10(-5) per viable cell. In addition, chromosomal DNA prepared from one R. meliloti strain resistant to streptomycin was transferred to the isoleucine-valine-requiring mutant susceptible to streptomycin.

Chromosomes, Bacterial↗
PubMed1987

[Halitosis].

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Halitosis↗
PubMed1986

[Halitosis].

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Digestive System Diseases↗