Dérivés glucosés des acides hydroxycinnamiques de la tomate: Évolution au cours de la vie du fruit et formation in vitro

Glucose derivatives of hydroxycinnamic acids have been identified in tomato fruits either as esters or glucosides, the latter always being the most abundant and increasing during growth and at the time of ripening. These compounds can be synthesized in vitro by a fruit glucosyltransferase from free hydroxycinnamic acids and UDPG; glucosides are always formed in higher amounts than esters.     

Dérivés d'acides 3-(β-d-érythrofuranosyl)-pyrazolecarboxyliques

Treatment of 2,5-anhydro-1-bromo-1-deoxy-2,3-O-isopropylidene-1-p-nitrophenylhydrazono-d-ribose with methyl acetylenecarboxylate gave methyl 3-(2,3-O-isopropylidene-β-d-erythrofuranosyl)-1-p-nitrophenylpyrazole- (8) and 5-carboxylate (9). Amidification at C-5 of 8 was easier than at C-4 of 9. Similarly, dimethyl 3-(2,3-O-isopropylidene-β-d-erythrofuranosyl)- 1 - p-nitrophenylpyrazole-4,5-dicarboxylate gave specifically a 5-carbamoyl derivative, the structure of which was established by comparison of the ¹³C-n.m.r.spectrum with those of a series of glycosylpyrazoles. The correlation between the experimental values of the chemical shifts of the carbon atoms of the pyrazole ring and the values calculated by addition of the contributions of the various groups linked to the ring was better (R 0.98) than the correlations obtained by calculation by the CNDO/2 method of the total electron population (R 0.92) or of the π-electron population of each carbon atom (R 0.85).     

Synthèse du méthyl-2-acétamido-2-désoxy-β-D-glucofuranoside et de dérivés

Methyl 2-acetamido-2-deoxy-5,6-O-isopropylidene-β-D-glucofuranoside was prepared in excellent yield from methyl 2-benzamido-2-deoxy-5,6-O-isopropylidene-β-D-glucofuranoside by alkaline hydrolysis, followed by selective N-acetylation. Treatment with 60% acetic acid at room temperature gave syrupy methyl 2-acetamido-2-deoxy-β-D-glucofuranoside, characterized by a crystalline tri-O-p-nitrobenzoyl derivative. The same treatment, at 100° gave methyl 2-acetamido-2-deoxy-β-D-glucopyranoside. In an alternative procedure, the selective N-acetylation was performed after acetic acid hydrolysis of methyl 2-amino-2-deoxy-5,6-O-isopropylidene-β-D-glucofuranoside. Several derivatives of methyl 2-acetamido-2-deoxy-β-D-glucofuranoside were prepared and compared with the corresponding pyranosides. The furanoside structure was clearly demonstrated by mass spectrometry and periodate oxidation.     

Les responsabilités du biologistes

The responsabilities of the professionals are numerous and various. As an exemple, we discuss the french law (29 july 1994) about the practice of reproductive biology. There are three levels of responsabilities:

? civil liability concern the damage to somebody, the means, information, confidentiality.

? penal code concern the integrity of somebody, the safety of the staff and of the patients.

? administrative.

All the professionals must be aware of the legislation and the penalties they might incur.     

Marqueurs du tractus génital et activités glycosidasiques séminales

Seminal liquefaction corresponds to a proteolysis of glycoproteins and could also result in a lysis of linked glycans involving glycosidases. It is well known that α-1-4 glucosidase is a real epipidymal marker. The aim of this study is to point out new markers among the glycosidases and especially β-D-mannosidase, α-L-fucosidase and N-acetyl-β-D-glucosaminidase. There is no correlation between the three enzymatic activities and the sperm count. Moreover in case of azoospermia enzymatic activities were always present. The variations observed are both quantitative (β-MAN activity is significantly decreased) and qualitative (modifications of the relative proportions of the different enzymatic forms) according to the etiology of azoospermia.     

Les sépultures italiennes du Paléolithique supérieur. Reconstitutions du régime alimentaire

The identification of dietary habits is increasingly seen as a fundamental aspect for studying the ancient human populations. Accordingly, several projects aiming to identify Paleolithic individuals’ dietary patterns were developed to analyze the organic component of bone tissue and identify isotopic markers to reconstruct the food typology. Bone fragments from six individuals were selected for carbon and nitrogen stable isotopes analysis. The interpretation of human isotopic data was framed through a dataset of twenty-one Italian Paleolithic individuals. The isotopic data generated for the Paleolithic individuals agree with the information already provided by the archaeological record concerning the Italian hunter and gatherer communities. Their subsistence economy was essentially grounded upon the exploitation of high protein foods, either from terrestrial fauna resources or inland lacustrine or riverine species.     

Taxonomie numérique de lactobacilles isolés du vin

Résumé L'auteur a déterminé les relations taxonomiques existant entre 65 souches de lactobacilles isolés du vin et 4 souches de collection, à l'aide de l'analyse adansonienne. Sept phénons 80 et deux phénons 72 sont décrits: ces deux derniers correspondent aux sous genres Streptobacterium et Betabacterium. Deux phénons 80 sont assimilables aux espèces Lactobacillus casei et Lactobacillus plantarum. Les autres phénons comportant plus d'une souche ne correspondent à aucune espèce décrite.Ce travail montre que l'on peut mettre en évidence les caractères phénétiques les plus représentatifs pour les regrouper ensuite dans une clé d'identification et que l'on peut juger de la valeur taxonomique d'un caractère d'intérêt pratique.

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Numerical taxonomy of lactobacilli isolated from wines

Summary The author has established the taxonomic relationships between 65 strains of lactobacilli isolated from wines and 4 named cultures, by means of adansonian analysis. Seven 80 phenons and two 72 phenons are described. The latter correspond to the subgenera Streptobacterium and Betabacterium. Two 80 phenons answer to the species L. casei and L. plantarum. The others 80 phenons of more than a strain do not correspond to any known species.This study shows that we can isolate the most representative phenetic characters and gather them again in an identification key and that we can appreciate the taxonomic value of a practical character.

     

Activité cytokinine de dérivés acylés,alkylés,acyl-alkylés de l'adénine et d'isost`eres azotés de la γ,γ-diméthylallyladénine

The cytokinin activities of various 6-acylaminopurines, 6-alkylaminopurines, 6-acylamino-9-benzyl-purines as well as a series of isosteric-nitrogen derivatives of N⁶-(γ, γ-dimethylallyl)adenine (I⁶Ade) have been tested using the tobacco pith and the pea bud bioassays. The interactions between active, slightly active and inactive compounds have been studied with the last assay. Acylation decreases the biological activity; e.g., N⁶-benzoyl and N⁶-furoyladenines are less active than Na⁶-benzyladenine and kinetin. Substitution at the 9-position reduces (tobacco-pith assay) or suppresses (pea-bud assay) the phytohormonal activity of otherwise active 6-acylaminopurines. In isosteric derivatives, maximum activity occurs when the side chain has the same length as in 1⁶Ade. After the analysis of interactions between more or less active compounds, it is suggested that the differences in cytokinin activity could be related to unequal affinities for a hypothetical receptor site.     

Prostasomes, dérivés actifs de l’oxygène et sperme humain

Prostasomes are particular lipid vesicles secreted by the human prostate and found in the semen. No specific action has yet been attributed to prostasomes, but they appear to act at various levels. For example, prostasomes enhance sperm motility in vitro and participate in the immunomodulation properties of seminal plasma. Excessive production of reactive oxygen species (ROS) in human semen has a negative influence on the functional capacities of spermatozoa. The presence of leukocytes in semen is associated with increased production of ROS that can be harmful to sperm cells, under certain conditions. Previous results tend to suggest a possible role of prostasomes on ROS production in human semen. After reviewing the literature concerning the structural and functional characteristics of prostasomes and the role of ROS in human semen, we report our results concerning the influence of prostasomes on ROS production and the consequences on semen. We have demonstrated that prostasomes exert an antioxidant function in human semen. This function is effective both on polymorphonuclear neutrophils and on sperm cells. The mechanism of action of prostasomes is unusual, as they act on ROS production mainly on the plasma membranes of neutrophils. They induce a decrease of NADPH-oxidase activity associated with rigidification of the plasma membrane. Prostasomes protect the functional capacities of spermatozoa during an oxidative stress created by the presence of NADPH in the incubation medium.     

Étude du Métabolisme D'acides Aminés ChezAspergillus oryzae

Résumé Lorsque l'on cultiveAspergillus oryzae w.f. sur une solution de substitution contenant un des acides aminés suivants: glycine, alanine, sérine, acide aspartique, thréonine, valine leucine, isoleucine, proline, hydroxyproline, arginine, ornithine et citrulline, on retrouve toujours à l'état libre dans son mycélium de l'acide glutamique et de l'alanine; on y décèle presque toujours la glutamine et l'acide aspartique. Par contre on n'y rencontre jamais, à moins que par simple diffusion, ou bien encore rarement, la glycine, la thréonine, la leucine, l'isoleucine, l'hydroxyproline et la citrulline. Quant à l'acide γ-aminobutyrique, il ne se décèle que dans le mycélium cultivé aux dépens de thréonine, de valine, de leucine, d'isoleucine, d'arginine, de citrulline et d'ornithine. Enfin, lorsque l'on prend une solution d'ornithine comme liquide de substitution on constate la présence dans le mycélium d'une substance aminée non identifiée. Ces diverses observations attribuent aux réactions de transamination, qui donnent lieu à la formation d'acide glutamique, d'alanine et d'acide aspartique, un r?le central dans le métabolisme ternaire et quaternaire de la moisissure étudiée.