ÉTUDE DE LA PHÉROMONE SEXUELLE DE LA TEIGNE DU POIREAU ACROLEPIOPSIS ASSECTELLA

Le composant principal de la sécrétion phéromonale produite parla femelle vierge de Acrolepiopsis (Acrolepia) assectella Zell. a été identifié par chromatographie en phase gazeuse, spectrométrie de masse, tests électrophysiologiques et olfactométrie comme étant l'hexadécène-11Z al (Z₁₁HDal). Ce composé est le plus actif en électrophysiologie parmi tous les autres acétates, alcools, aldéhydes et formiates, de C₁₂ à C₁₈, éprouvés sur l'antenne du mâle et il est capable de produire chez ce dernier une séquence comportementale sexuelle complète en olfactomètre à tube. Dans la nature, des capsules en caoutchouc chargées à 1 mg de Z₁₁HDal (plus 10% d'antioxydant) attirent sélectivement les mâles et sont compétitives avec des femelles vierges. L'isomère E (E ₁₁HDal) est environ 10⁴ fois moins actif tandis que l'acétoxy-1 hexadécène-11Z (Z₁₁HDA) et l'hexadécène-11Z ol-1 (Z₁₁HDol) inhibent le pouvoir attractif du Z₁₁HDal.

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Summary The main component of the sex pheromone secretion produced by virgin females of A. assectella has been identified as Z-11 hexadecenal (Z₁₁HDal) by GC analysis and mass spectrometry, EAG tests, and behavioural assays. Z₁₁HDal elicited the highest EAG response of all C₁₂ to C₁₈ acetates, aldehydes, formates and alcohols tested, and induced a typical sequence of male sexual behavioural responses in olfactometer tests. In the field, traps baited with 1 mg Z₁₁HDal on rubber septa (with 10% antioxidant) attracted male moths selectively and were competitive with virgin females. The E isomer (E ₁₁HDal) was 10⁴ times less attractive, whereas Z11-hexadecenyl acetate and Z11-hexadecen-1-ol, in admixture with Z₁₁HDal strongly inhibited male responses.

     

ÉTUDE DE LA TEMPÉRATURE CORPORELLE DE LA BLATTE, À TEMPÉRATURE AMBIANTE VARIABLE

Résumé La température interne d'un insecte dictyoptère femelle, Blaberus craniifer Burm., est détectée par une thermistance disposée dans la cavité incubatrice de l'animal. Sa température ambiante est soumise à une variation périodique de faible amplitude. Ce protocole expérimental permet de préciser les phénomènes d'adaptation thermique d'un poïkilotherme.

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Summary The thermal adaptation of Blaberus craniifer (Insecta Dictyoptera) was studied. The body-temperature measurements were made on the animal kept in a regulated box. Simultaneously we recorded the temperature of a similar box as a control. Both boxes were submitted to a pseudosinusoidal variation of temperature of low amplitude.The analysis of the curves obtained shows that variation of the body temperature is dephased and damped in comparison with the control box temperature. When the animal is previously killed the dephasing decreases and the damping increases.An increase of thermal inertia in the living insect is also observed.

     

VORTOJ POR LA ELDONO DE LA BULTENO

"Se oni volas entrepreni esploradon de naturo, oni devas etrepreni unue gianklasifikadon kaj scii la diferencajn nomojn."Ekde la komenco de la nova longa marso por efektivigi la kvar modernigojnen nia lando, la esploraj laboroj de faunaj studoj de insektoj, biologia kontrolo kajinsekta ekologio jam vaste disvolvigas tra la tuta lando. La enketo de biologiaj     

INFLUENCE DE LA TENEUR EN EAU ET DE LA DURETÉ DU TÉGUMENT DES GRAINES DE PHASEOLUS VULGARIS SUR LA FRÉQUENCE DE PÉNÉTRATION DES LARVES NÉONATES D'ACANTHOSCELIDES OBTECTUS

Les larves néonates d'Acanthoscelides obtectus Say (Col. Bruchidae) doivent percer le tégument des graines de Phaseolus vulguris pour effectuer leur développement dans les cotylédons. Ce tégument représente une véritable barrière tant mécanique que chimique. La dureté de celui-ci est un facteur important qui influence la fréquence de pénétration larvaire. Nous le montrons en contrôlant la teneur en eau du tégument un des facteurs déterminant de la dureté de celui-cl. l'âge des graines influence aussi la fréquence de percement indépendamment de la teneur en eau du tégument.     

Human SS-B/LA autoantigen contains a covalent protein-RNA linkage

The chemical nature of association of RNA in immunoprecipitates of human SS-B/La ribonucleoprotein, an autoantigen expressed in various autoimmune disorders, was investigated. A fraction of RNA associated with SS-B/La immunoprecipitates was readily dissociated by SDS-polyacrylamide gel electrophoresis, yielding four main subfractions, R1-4, with chain lengths in the range of 90-130 nucleotides (R4), 140-175 nucleotides (R2 and R3) and above 200 nucleotides (R1). Moreover, the immunoreactive protein component, migrating with a molecular mass of 49 kDa, contained a very tightly bound RNA co-migrating with the protein unless the protein was proteolytically degraded. Most of the RNA molecules in this fraction, represented by about 20 components, had a free 3'-terminus but a blocked 5'-terminus and showed chain lengths between 10 and 125 nucleotides. After pretreatment with alkaline phosphatase and a mixture of ribonucleases T1 + T2 + A, adenosine 3',5'-biphosphate (pAp) was liberated by phosphodiesterase (Crotalus durissus) as the blocked 5'-end of the RNA. The chemical nature of the blockage was revealed after alternative treatment of the protein-pAp component with phosphodiesterase or nuclease S7 followed by acid hydrolysis and phosphoamino acid analysis which showed that a threonine residue must be directly involved in the RNA-protein linkage of 49 kDa SS/La antigen, indicating the presence of a covalent threonine-pAp bond.     

Regulatory enzymes of lipid metabolism in LA/N-cp rats

Hepatic activities of rate limiting enzymes in fatty acid and cholesterol synthesis and cholesterol degradation were determined in lean and obese LA/N-cp rats. The hepatic activities of acetyl-CoA carboxylase and fatty acid synthetase, the key enzymes of fatty acid synthesis and 3-hydroxy-3-methylglutaryl coenzyme A reductase (the rate limiting enzyme in cholesterol synthesis), were increased 2-fold in the obese rats as compared with their lean littermates. In contrast, the activity of cholesterol 7alpha-hydroxylase, the rate limiting enzyme of cholesterol degradation to bile acids, was significantly decreased by 28% in the obese group as compared with the control group. Significantly, compared with the control group, the obese animals exhibited similar magnitudes of differences in the activities of the above enzymes even when they were pair-fed with the control animals. Thus these differences in the obese group are not due to hyperphagia but possibly to hypersecretion of the lipogenic hormone, insulin in this strain. These results indicate that the LA/N-cp obese rat has twice the capacity to synthesize body fat and cholesterol but has a reduced capacity to degrade the cholesterol, leading to increased accumulation of cholesterol and fat.     

Myocardial and vascular lesions in the LA/N-corpulent rat

The LA/N-corpulent (LA/N-cp) rat is a normotensive strain derived from Koltesky's original mutant strain of the spontaneously hypertensive rat (SHR). When homozygous for the cp gene (cp/cp), the rats are hyperphagous, hyperlipidemic, hyperinsulinemic, and obese. The rats have been shown, by scanning electron microscope observation of the arterial system, to develop arterial lesions and occasional occlusive thrombi. These are significantly more frequent in the corpulent rats. Histological examination of the heart has shown the presence of four distinguishable types of lesions: type A, muscle scar or cell dropout with pigment deposition and inflammatory cell accumulation; type B, necrosis of a small number of myocytes with reactive inflammatory cells; type C, nodule of chronic inflammatory cells; type D, muscle scar without chronic inflammatory cells. Complete transverse sections of three regions of the heart were examined from rats 3, 6, and 9 months of age. Rats that were homozygous normal (+/+) showed an absence of all types of cardiac lesions. Male corpulent rats showed frequent lesions of all types with the frequency rising consistently with age. Female corpulent rats showed a similar incidence of types C and D lesions to males, but no type B lesions were found. Type A lesions, the most common in corpulent males, were found at a greatly reduced relative frequency. In some instances, we have found occlusive thrombi in a coronary artery of corpulent rats. The disease process in these animals occurs with a normal low fat, virtually cholesterol-free diet and no experimental manipulation.