The 11th international workshop on the CCN family of genes in pictures

The 11th International Workshop on the CCN Family of Genes organized in Nice from October 20th to October 24th, 2022, was the occasion to celebrate the 20th anniversary of the ICCNS meetings.

In order to mark this special event, and as a co-organizer of the workshop, I shot pictures to illustrate the nice days that we spent with all the scientists who accepted to participate in this new episode of the ICCNS workshop series.     

Association of the quinate : NAD+ oxidoreductase with one dehydroquinate hydro-lyase isoenzyme in corn seedlings

A quinate : NAD⁺ oxidoreductase has been purified from cornseedlings. This enzyme co-migrates with a dehydroquinate hydro-lyaseisoenzyme whatever separation technic is used. This is strongevidence that the two activities are associated in an enzymecomplex or in a bifunctional enzyme, in addition to the previouslycharacterized association of the shikimate : NADP⁺ oxidoreductaseand another dehydroquinate hydro-lyase isoenzyme. The purifiedquinate : NAD⁺ oxidoreductase has a poor affinity for quinicacid and is only active in the presence of NAD⁺. The associateddehydroquinate hydro-lyase isoenzyme is strongly activated invitro by shikimic acid in a pH-dependent process. The possible role of this new association is discussed in thelight of previous results from alicyclic metabolism studiesin plants and microorganisms. (Received July 18, 1980; )     

Histamine production by wine lactic acid bacteria: isolation of a histamine-producingstrain of Leuconostoc oenos

Populations of Leuconostoc œnos were harvested from wines containing a relatively high concentration of biogenic amines. Cultivation of the biomass in synthetic media and wine showed that it consisted of histamine-producing strains. Histamine levels after culture depended on the quantity of precursor available and on the presence of yeast lees, which certainly enriched the medium in histidine. Ethanol and pH, which control bacterial growth rate and total population, were also significant factors: pH and low ethanol concentration enhanced histamine production.
Strain Leuc. œnos 9204 was isolated and studied since it retained its ability to produce histamine after several transfers. In synthetic medium this strain produced large amounts of histamine especially in the poorest nutritional conditions (no glucose, no L-malic acid). These results clearly demonstrate that Leuc. œnos involvedin wine-making might play a role in biogenic amine production. The vinification method might also influence the final amine concentration in wine.     

Purification and properties of 6-phosphogluconate dehydrogenase from sheep liver

A method is described for the isolation of 6-phosphogluconate dehydrogenase from sheep liver. The product appears to be homogeneous in polyacrylamide-gel electrophoresis and in sedimentation-velocity and sedimentation-equilibrium studies in the ultracentrifuge. The molecular weight is estimated as 129000 from equilibrium sedimentation.     

Argovithyris nov. gen. ET A. Birmensdorfensis (Brachiopoda) des couches a spongiaires de l'oxfordien moyen du Jura

The «Couches de Birmensdorf give, in Argovie (Switzerland) as in southern FrenchJura, a small Terebratulid: T. birmensdorfensisMoesch for which a new genus is defined: Argovithyris nov. gen. because it cannot be assigned to genus Loboidothyris.     

Gastric (H,K)-ATPase

Gastric acid secretion results from the activity of a specific ATPase, the (H+,K+)-ATPase. This enzyme, discovered in 1973, exchanges H+ for K+. It has two ATP binding sites, both involved in enzyme activity, whose affinities vary as a function of the H+ and K+ concentrations. Hydrolysis of ATP at the highest affinity site leads to the synthesis of a covalent aspartyl phosphate which accumulates in the absence of K+. The presence of this cation accelerates dephosphorylation resulting in the stimulation of ATPase (and PNPPase) activity. The structure of membranous (H+,K+)-ATPase is poorly defined. n-Octylglucoside solubilizes an active enzyme of 390-420 kDa which can be partly depolymerized using cholate. The monomer, characterized in SDS has a 95 kDa molecular mass and is inactive. In the presence of magnesium, (H+,K+)-ATPase catalyzes the active and neutral exchange of H+ for K+ at the expense of ATP. In the absence of ATP, (H+,K+)-ATPase acts as a passive transporter exchanging K+ for K+ at maximal rate and H+ for K+ at a 20 times slower rate.     

One-Electron Reduction of Daunorubicin Intercalated in DNA or in A Protein : A Radiolysis Study

The one-electron reduction of daunorubicin, an anthracycline antibiotic, intercalated in DNA or in the apoprotein of the riboflavin binding protein, was studied by y radiolysis. The two reduction mechanisms appear very similar to the one found for the non-intercalated drug. Hydrogen peroxide, which oxidizes non-intercalated hydroquinone daunorubicin with two electrons in one step (C. Houee-Levin, M. Gardes-Albert and C. Ferradin, FEBS lett. 173 27-30, (1984), reacts with daunorubicin hydroquinone in DNA but not in the protein. It appears thus that the site accessibility to hydrogen peroxide in DNA is better than in the protein. Biological consquences are discussed.