Analyse comparative de la séquence sexuelle chez les Ipopodes Oniscoidea de la série ligienne en relation avec le développement de la volvation chez les Armadillidiidae et les Armadillidae

A comparative study of the sexual sequence is carried out in four Oniscoidea of the ligiid series Porcellio laevis, Metoponorthus sexfasciatus (Porcellionidae), Armadillidium vulgare (Armadillidiidae) and Armadillo officinalis (Armadillidae). The differences between the four species chiefly appear in the precopulatory manoeuvres. The integration of coiling or uncoiling reactions in the sexual sequence of coiling forms is studied in two genera: Armadillidium and Armadillo. Results of the behavioral study provide information about the evolution of the group.     

Analyse formelle de circuits de régulation génétique: le contrôle de l'immunité chez les bactériophages lambdoïdes

This paper is an attempt to describe and analyze in formal terms a genetic circuit which is rather complex and reasonably well disentangled: the control of immunity in lambdoid bacteriophages. Known models are expressed as logic equations, which relate the stade of activity of genes to variables of three kinds: genetic variables which describe the genotype of the organism, environmental variables like temperature and memorization variables. The value of each memorization variable (presence or absence of a gene product) is related to the value of the corresponding function (operation or not of the gene) by two characteristic time delays, an «establishment delay and a «decay delay.From the equations, one can derive matrices which facilitate comparison between models by showing which stable states are predicted by each model. Implications of current models, which had apparently remained cryptic, have been realized and experimentally tested.From the matrices, one can derive graphs which show the pathways (sequences of states) consistent with each model. These graphs are frequently branched and in these cases one has to analyze which conditions determine that one pathway rather than another one, is followed.     

Variations des zymogrammes estérasiques chez les larves de Palaemon serratus soumises à différentes durées de choc thermique

Palaemon serratus at larval stage 2, acclimatized at 16°, were subjected to a temperature increase of 15° for periods of 5, 20 or 40 min with or without return to the initial temperature for 12 h. The soluble protein concentration of larvae subjected to a thermal shock of 20 min duration is lower than in control larvae. Total esterase-2C activity per mg of soluble protein after a thermal shock of 20 min duration is less than in control larvae but, in contrast with larvae subjected to a shock of 40 min duration, the initial activity is restored after 12 hours. Esterase-2C activity zymograms, after polyacrylamide gradient gel electrophoresis, show twelve isozymes. The activity of each isozyme examined varies according to the duration of the thermal shock.     

Morphologie des épines chez les brachiopodes Delthyrididae

Two main types of micro-ornament can be observed in the family Delthyrididae (Brachiopoda, Spiriferidina): capillae (with continuity of the structures from one growth lamella to the next one) and spines (with the appearance of discontinuity). SEM studies of the spines show that, contrary to previous assumption, the cross section is not circular but subquadrangular with a longitudinal groove on top. Each spine is connected in front to the next one so that they give rise to a continuous radial structure. Thus the spine is a local external differentiation of the underlying microfila. Furthermore, the spinose ornament is derived from the capillate ornament. During growth, new fila and spines appear in the grooves and diverge towards the top of adjacent costae, running across several lamellae. When there are few spines, they have a uniform size, but when there are many spines, small spines (issued from newer fila) are juxtaposed with large spines (issued from older fila). The use of micro-ornament in systematics has often been based on misinterpretations; attention is drawn to the fact that the shape of the spine base is not representative of the original shape of the spine but generally resulted from the erosion of the shell. Nevertheless, more detailed studies on spine shape and arrangement offer interesting prospects for classification.     

Les marques de croissance osseuse comme indicateurs de l‘âge chez les lézards

Abstract From a comparative viewpoint, this paper deals with structural and functional aspects of skeletal annulations in lizards, especially those displayed by sections cut transversally through the larger bones of the appendages. Cross-sections of the diaphyses exhibit an alternation of concentrically arranged thinner and thicker annulations which were formed during colder and warmer seasons, respectively. The thinner annulations are chromophile and anisotropic but not hypermineralized; they are generally referred to as “resting lines” or “adhesion lines” and are due to a slowing down of the temperature-dependent growth process; they also differ structurally from “cementing reversal lines”. In certain cases, the thinner annulations (here called LAC) are surrounded by bone lamellae and thus compare closely with the annuli on the flat bones. From the study of two lizards of known age, as well as on the basis of a preliminary experimentation with fluorochrom labelling, it has been demonstrated conclusively that the recurrence of the LAC in lacertilians shows an annual regularity. Therefore, it would seem that the LAC can be employed for age determination in lizards.     

Memorisation des marques olfactives chez la Genette (Genetta genetta L.): durée de reconnaissance par les femelles de marques olfactives de males

Memorization of Scent Marks in Genets (Genetta genetta L.): Duration of Female Memory of Male Scent Marks The aim of this work was to study the memorization of scent marks of known males by females in genets (Genetta genetta L.). An attempt was made to determine how long, after separation from a given male, females could discriminate between his scent marks and those of strange males. Significant differences in sniffing duration at the scent marks were observed nine weeks after separation. These results showed that olfactory cues could permit individual recognition in genets, and that memorizing the scent marks could also act in the regulation of aggressive behaviour in free-living animals.     

Caractères et évolution des enzymes chitinolytiques chez les vertébrés infèrieurs

The activity of chitinases extracted from various organs of different fish, amphibians and reptiles was estimated as a function of pH by using “native” chitin as substrate. Three types of chitinase activity were recorded, suggesting the existence of three different chitinase types: Type 1: (optimum pH; 4.5, no activity at pH 1.0) was found in various organs, such as intestine, pyloric caeca, pancreas, liver, spleen, etc.); Type IIa: (optimum pH; 3.0, weak activity at pH 1.0) was obtained from the gastric mucosa of fish and one species of urodele; Type IIb: (optimum pH; 3.0, strong activity at pH 1.0) was found in the gastric mucosa of reptiles and batrachian anura. Chitinase activity appears to be adapted to the pH of the digestive fluids. A tentative scheme is presented of chitinase evolution among lower vertebrates.     

Aspects ultrastructuraux et synthèse de la thyroglobouline dans les cultures de thyroides avant et après transplantation chez des rats hypophysectomisés

Two aspects concerning the study of thyroglobulin synthesis and of the ultrastructure of thyroid glands in organotypic cultures have been studied: (1) the chronology of ultrastructural alterations in thyroid cultures leading to the loss of thyroglobulin synthesis; and (2) the role of TSH in the re-establishment of the characteristic features in the cultured cells following transplantation.Alterations of the endoplasmic reticulum start on the very first day of culture. The ribosomes detach themselves from the membranes which then disappear. On the third and fourth day, significant alterations are observed on mitochondria and nuclei. The lysosomes disappear, while the Golgi apparatus is hardly affected.All the above modifications are reversible, since it is possible to re-establish the characteristic features of the endoplasmic reticulum and the synthesis of thyroglobulin after transplantation of the cultured glands into normal animals.The reappearance of phenotypic traits of the thyroid cells can also be obtained after transplantation into hypophysectomized rats. However, the level of thyroglobulin synthesis in these transplants, which is similar to that in the host gland, is lower than in grafts into normal animals.This results shows that TSH is not required for differentiation and for manifestation of the phenotypic traits of the thyroid gland. It seems therefore that the role of TSH is not to stimulate differentiation, but to maintain and regulate the level of specific processes in the already differentiated thyroid cell.     

Effet des rayons gamma sur les larves de Plodia interpunctella (Lepidoptera: Phycitidae)

Résumé On peut envisager de protéger les produits emmagasinés tels que pistaches, noix, amandes, noisettes décortiquées, contre les détériorations dûes aux pullulations des larves et adultes de Plodia interpunctella (Lépidopt. Phycitidae), en irradiant ces produits avec des doses appropriées de rayons gamma. Nos expériences montrent que des doses de 10 Krads appliquées à des larves du dernier stade, prolongent la durée de la vie nymphale, réduisent le pourcentage d'émergence des imagos et provoquent chez les femelles une régression des ovaires. Ces effets sont encore plus marqués avec des doses de 12 et 14 Krads. Cette dernière dose pourrait être la dose optimum à envisager.

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Summary Protection of stored products such as pistachio nuts, walnuts, almonds and shelled hazel nuts against damage from infestation by larvae and adults of Plodia interpunctella (Lepidoptera: Phycitidae) by radiating these products with appropriate doses of gamma rays, can now be considered. Our tests show that doses of 10 krad applied to last-stage larvae prolong the length of pupal life, reduce the percentage of imaginal emergence and cause regression of the female ovaries. These effects are even more pronounced with doses of 12 and 14 krad. This last dose may well deserve the most attention.

     

Modéliser les interactions moléculaires par la théorie des réseaux de jeux

We present a method to model biological systems, the theory of games networks. It extends game theory by multiplying the number of games, and by allowing agents to play several games simultaneously. Some important notions of biological systems, such as locality of interactions and modularity, can then be modelled. To cite this article: M. Manceny et al., C. R. Biologies 329 (2006).     

Sur la coloration histologique contrastee des hypes chez les insectes atteints de mycose

Résumé Pour la mise en évidence histopathologique du mode d'infection des insectes par les champignons pathogènes, des colorations très contrastées des hyphes sont nécessaires. C'est pourquoi nous avons comparé les méthodes appropriées les plus récentes de la mycologie médicale sur des coupes d'une larve de Melolontha melolontha atteinte par Beauveria tenella. La coloration de De Palma & Young (1963) s'est avérée excellente et simple; les méthodes de Grocott (1955), ainsi que de Kelly, Morgan & Saini (1962) donnent également de bons résultats.

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Summary The suitability of staining methods recently developed in medical mycology was tested for histopathological investigations of insect mycoses. One third instar larva of Melolontha melolontha, heavily infected with Beauveria tenella was used as test material. Good results were obtained by staining the sections according to the method of De Palma & Young: hyphae and host tissues can easily be recognized by differences in colour. The condition of the host tissue can also easily be judged. Moreover, the technique is simple. The staining methods by Grocott (1955) and Kelly, Morgan & Saini (1962) are also suitable for the fast locating of hyphae in the host. Combination of the staining of Grocott with counterstaining methods (for example with safranin, light green or acidic fuchsin light green) gives a contrasting presentation of the host tissues as is sometimes desired. The method of Amargier & Vago (1966), described for insect-pathological work, gives a good contrasting picture of the hyphae in the endocuticle, but less contrast in other host tissues.