Detection of antigenic determinants of membranes using an insoluble peanut lectin]

The binding of lectins on insoluble supports may be used to detect the interactions occurring between these molecules and the sites of some receptors of membranes. An example is given, using the "anti-T" lectin extracted from peanut, to show the presence of determinants with terminal free glactose on the surface of erythrocytes and lymphocytes.     

HLA groups in the infantile psychoses during development, and hypothesis for an enzyme defect]

The HLA typing (loci A and B) of a series of fifteen psychotic children has shown an increase of the frequency of both HLA-A9 and B5 antigens. These preliminary data and previous biochemical findings in psychotic patients lead the authors to postulate the hypothesis of a qualitative or quantitative anomaly of the superoxide dismutase (SOD-2), the gene of which is situated on the same chromosome (sixth) as the HLA complex.     

Detection of schistosomiasis in rats using micro blood sampling and immunofluorescence during an epidemiologic study]

For a study of rat parasitism with Schistosoma mansoni in Guadeloupe, we used a technique of microbloodsampling followed by an immunofluorescence test. This method makes it possible to take the blood of the rats, the latter being then marked and set loose. It informs us of the presence of the parasite, the time of infestation, and the rats' movements relative to waterspots.     

"Milk aflatoxin" and transfer of toxicity]

Diet including 20 p. 100 of lyophilised milk produced by Goat who consumes peanut meals containing 1,530, 79 and 54 microng/kg aflatoxins with 1,136, 64 and 54 microng/kg aflatoxin B1, is given to duckling during 23 days. There is no influence of this diet on growth, feed efficiency and liver or kidney histology. In contrast, direct consummation of Peanut meal, with the highest level of aflatoxins, produces 18 p. 100 mortality and characteristic injuries of aflatoxiocsis.     

Regulation and electric excitation of enzyme membranes in vitro]

Enzyme membranes can be activated or inhibited by applying continuous or alternating electrical fields. The field can modify the transport or reaction term of the transport-reaction by action on the displacement of charged species including those giving pH effects or inducing volume flows. A first experimental example is given: the progressive supression of the inhibition of hexokinase by the product when increasing alternating fields are applied. In the same way the apparent optimal pH approaches that of the soluble enzyme. In addition to its theoretical and practical implications electrical regulation can lead to the monitoring of enzyme reaction-driven mechanochemical fibers.     

The Na+, K+, Ca2+, Mg2+ and Cl− composition of giant fibers fromBalanus nubilus

Zusammenfassung Es werden Analysenresultate über den Ionengehalt von einzelnen Muskelfasern der Entenmuschel,Balanus nubilus, mitgeteilt. Es wurden Unterschiede nachgewiesen in der Ionenkonzentration verschiedener Fasern, die von demselben Muskelbündel isoliert worden waren.     

Statistical relationship between "slow-wave sleep" and "paradoxical sleep" in rats]

In the Rat, statistical analysis of slow sleep (SS) and paradoxical sleep (PS) episodes disclosed two significant (p less than 0,01) positive correlations: (1) Over a four-hour period, the mean duration of PS episodes was correlated to the mean of the just preceding "light" SS episodes; (2) On the contrary, from cycle to cycle of sleep-wakefulness, the duration of each PS episode was correlated to that of the "light" SS episode of the next cycle.     

Peroxiredoxin 2 (<Emphasis Type="Italic">PRDX2</Emphasis>), an antioxidant enzyme,is underexpressed in Down syndrome fetal brains

Suppression subtractive hybridization performed on Down syndrome (DS) versus control fetal brains revealed differential expression of peroxiredoxin 2 (PRDX2), mapped at 13q12. Peroxiredoxins are antioxidant enzymes involved in protein and lipid protection against oxidative injury and in cellular signalling pathways regulating apoptosis. The under-expression of PRDX2 observed in DS samples was confirmed by realtime PCR (0.73-fold). To test whether decreased expression is associated with enhanced sensitivity of DS neurons to reactive oxygen species, we down-regulated PRDX2 through stable transfections of SH-SY5Y neuroblastoma cells with antisense contructs of the complete PRDX2 coding sequence. In addition, we over-expressed SOD1 and compared the effects of the two genes on cell viability. Cells transfected with either construct showed similar sensitivity to oxidative stress in addition to increased apoptosis under basal conditions and after treatment with oxidative cytotoxic agents. This suggests that the decreased expression of PRDX2 may contribute to the altered redox state in DS at levels comparable to that of the increased expression of SOD1.Received 4 February 2003; received after revision 31 March 2003; accepted 25 April 2003     

Increase in Na+, K+ -ATPase enzyme units in liver and kidneys from essential fatty acid deficient rats.

(3H)-Ouabain binding to liver and kidney preparations was utilized to estimate the number of Na+, K+-ATPase enzyme units in livers and kidneys from rats fed 2% corn oil supplemented or fat-free diets. The specific (3H)-ouabain binding in liver and kidney preparations from fatty acid deficient rats was increased approximately 40%, but the affinity of the binding sites for ouabain (Kd-value) remained unchanged. The increased concentration of Na+, K+-ATPase enzyme units observed in the essential fatty acid deficient rats may contribute to the reduced body fat accumulation and elevated heat production observed in these animals.     

Lysyl oxidase: an oxidative enzyme and effector of cell function

Lysyl oxidase (LOX) oxidizes the side chain of peptidyl lysine converting specific lysine residues to residues of alpha-aminoadipic-delta-semialdehyde. This posttranslational chemical change permits the covalent crosslinking of the component chains of collagen and those of elastin, thus stabilizing the fibrous deposits of these proteins in the extracellular matrix. Four LOX-like (LOXL) proteins with varying degrees of similarity to LOX have been described, constituting a family of related proteins. LOX is synthesized as a preproprotein which emerges from the cell as proLOX and then is processed to the active enzyme by proteolysis. In addition to elastin and collagen, LOX can oxidize lysine within a variety of cationic proteins, suggesting that its functions extend beyond its role in the stabilization of the extracellular matrix. Indeed, recent findings reveal that LOX and LOXL proteins markedly influence cell behavior including chemotactic responses, proliferation, and shifts between the normal and malignant phenotypes.     

Demonstration of "hydroxylase" and "epoxide hydrase" activities in preparations of nucleoli isolated from rat liver]

Aryl hydrocarbon hydroxylase (AHH) activity and epoxyde hydrase (EH) activity have been found in Rat liver nucleoli obtained from untreated (C) and methylcholanthrene (MC) pretreated Rats. Electron microscopic observations of nucleolar preparations did not reveal significant contamination either by intact nuclei or by nuclear membranes. Very low but detectable activity of NADPH cytochrome C reductase was found in the nucleoli. Nucleolar preparations revealed little AHH activity (12-18 pmoles/min/mg). AHH was inducible by MC in nuclei but not in nucleoli. The presence of EH in nucleoli was demonstrated with phenanthrene 9,10-oxide (550-620 pmoles/min/mg) and benzopyrene 4,5-oxide (92-116 pmoles/min/mg). These values were lower than those obtained using intact nuclei. The addition of TCPO (10(-4) M) inhibited EH activity.     

The behavioral development of the mutant "staggerer" mouse]

The behavioural study, in particular rearing environmental conditions, of the mutant mouse staggerer has shown that such animals may live more than 90 days. (he behavioural diagnosis of this mutation has been possible from the second week of life, using specific tests. A typical "bat posture" permits one to recognize the mutant from the normal Mouse. Locomotory and feeding behaviours also present late and various qualitatige particularities.     

Occurrence of an enzyme acting on xanthopterin-B inBombyx mori

Résumé Nous avons démontré qualitativement chez leBombyx mori, l'existence d'un ferment qui attaque la xanthoptérine-B, une substance fluorescente du type ptérinique qui se trouve dans les intéguments des larves de race jaune «lemon», et se transforme en une substance non-fluorescente. Le ferment se trouve dans les épidermes, tissus adipeux des larves et dans les ufs et cocons desBombyx de type normal. Chez les mutants de la race jaune, l'activité du ferment est faible ou nulle dans bien des tissus. Cependant on ne peut pas nécessairement dire que la présence de ce ferment conduit à l'absence de la xanthoptérine-B, parce que l'accumulation de xanthoptérine-B est supprimée par l'action d'autres gènes chez les mutants «Striped marking» (p ^s ) ou «od-translucent» (od). Dans ces derniers l'activité du ferment est en effet très faible.     

Detection and localization of a ribonuclease activity associated with vaccinia virus]

A ribonuclease associated with vaccinia virus can be detected when reduced concentrations of nucleotides are used for an in vitro RNA synthesis assay. The non-viral origin of this ribonuclease may be inferred from its external location and from its variable activity on different purified virus stocks. The detection of this ribonuclease activity on purified virus grown without foetal Calf serum may suggest that this enzyme is of cellular origin.     

Detection of DDT in quail eggs: quantitative analysis]

Significant residues of DDT have been found in the albumin and vitellus of Quail eggs, after external treatment of the shell with an aqueous suspension of commercial DDT. The rate of pesticide crossing varies according to the shell porosity and thickness. Residues of DDT have also been found in the control eggs and in the Quail industrial food.