ACTION DE L'ANHYDRIDE CARBONIQUE ET DE FACTEURS VISUELS SUR LES PERFORMANCES DE PIEGES «MANITOBA» MODIFIES EN MILIEU MONTAGNARD

Résumé Les performances de pièges à Tabanidae de type Manitoba ont été étudiées en milieu montagnard et subalpin. On a testé les influences respectives de la présence ou de l'absence d'une source de CO₂, de la nature de cette source (solide ou gazeuse), de la présence ou de l'absence d'un leurre visuel (sphère noir brillant), de la nature transparente ou opaque de la partie supérieure du piège (hotte conique). Plus de 8.000 Tabanidae et plus de 51.000 Muscidae ont été pris au cours de ces essais totalisant 660 heures-pièges.

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Summary Manitoba traps, traps without decoy or with black canopy, unbaited or baited with dry ice or compressed carbon dioxide, were compared for the numbers of horse flies and muscid flies caught in mountainous mixed wood and pasture land and in subalpine larch forest between 1500 m and 2200 m, in July. More muscid flies were captured in the compressed CO₂ baited traps than in dry ice baited traps. Haematopota pluvialis, Tabanus maculicornis and Tabanus quatuornotatus were more attracted by CO₂ than Tabanus bromius. T. bromius was more attracted by the decoy than other species. The genus Atylotus and T. bromius are more attracted to the black canopy than other species. The visual decoy is more necessary to the efficiency of the trap than the chemical bait. The CO₂ baited Manitoba trap caught the greatest number of horse flies (180 per trap and per hour). The unbaited Manitoba trap was efficient too, but other traps were inefficient. About 8000 horse flies and 51000 muscid flies were caught.

     

RÉGULATION DE LA PRISE DE NOURRITURE,APRÈS UN JEÛNE,CHEZ LES MÂLES DE LA BLATTE GERMANIQUE DANS DIFFÉRENTES CONDITIONS ALIMENTAIRES

La consommation journalière d'un aliment semi-synthétique contenant des proportions variées d'une substance non-nutritive (alumine) a éTÉ étudiée chez les mâles adultes de la blatte germanique, Blattella germanica L., après trois joûrs de jeûne. Lors de la réalimentation, on observe une augmentation de la quantiTÉ de nourriture consommée au cours du premier jour, quelle que soit la dilution. La consommation décroît et atteint sa valeur habituelle au bout de trois jours avec des nourritures peu diluées. Avec des nourritures plus diluées, la consommation reste importante pendant toute la durée de l'expérience et les insectes ne peuvent pas récupérer leur déficit métabolique. L'ensemble des résultats permet de penser que la consommation de matière sèche est réglé ***pur plusieurs facteurs: propriétfés phago-stimulantes de la nourriture, réplétion du tube digestif, vitesse du transit, utilisation métabolique de la nourriture et déficience métabolique provoquée par le jeûne.     

LES COMPARTIMENTS D''ACETYLCHOLINE DE L''ORGANE ELECTRIQUE DE LA TORPILLE ET LEURS MODIFICATIONS PAR LA STIMULATION

Abstract— Changes in ‘free’ and ‘bound’ acetylcholine before and after stimulation have been investigated in vivo and in slices of electric organ of Torpedo marmorata incubated or superfused with physiological saline solutions. Spontaneous miniature end-plate potentials could be recorded and on electrical stimulation discharges of up to 30 V could be elicited. The electrical response fell off rapidly on repetitive stimulation. ‘Bound’ acetylcholine is that which relhains after the tissue has been homogenized since any ‘free’ acetylcholine is hydrolysed by the esterases when the tissue is disrupted. ‘Free’ acetylcholine can therefore be determined as the difference between the total acetylcholine found when the tissue is extracted with trichloroacetic acid and that which remains when the tissue is homogenized. Most of the ‘bound’ acetylcholine is present in synaptic vesicles. Stimulation of the tissue until the electrical response had fallen was accompanied by a drop in the level of ‘free’ acetylcholine. Lowered calcium and increased magnesium concentrations in the medium caused a decrease in the electrical response to stimulation and a decrease in the fall of ‘free’ acetylcholine. In other experiments, a decrease of both compartments was noticed at the end of the stimulation period. However the drop in ‘bound’ acetylcholine could also be elicited after the ‘free’ had fallen, by continuing the stimulation. When anticholinesterases were put in the medium, acetylcholine released on stimulation could be collected. On pre-incubation of the slice with [¹⁴C]choline, the acetylcholine stores became labelled. The specific radioactivity of the ‘free’ acetylcholine fluctuated on serial stimulations, whereas the specific radioactivity of the ‘bound’ acetylcholine remained stable under these experimental conditions. It is concluded that the ‘free’ compartment of acetylcholine is the most immediately available for release on stimulation.     

DONNÉES EXPÉRIMENTALES SUR LES CHANGEMENTS DE GALERIE DES LARVES MINEUSES DE PHILOPHYLLA HERACLEI (DIPTERA,TEPHRITIDAE)

Résumé Les larves de la mouche du céleri peuvent quitter leur galerie d'origine et en creuser une nouvelle dans le parenchyme d'une autre foliole. Ces changements se produisent lorsque la quantité de nourriture est insuffisante pour assurer le développement complet ou lorsque l'état physiologique de la feuille est mauvais.Des changements peuvent être induits expérimentalement en transférant les larves d'une foliole sur une autre, ou en augmentant la pression de la compétition intraspécifique; dans ce dernier cas le comportement d'alimentation peut être changé, les larves pouvant se nourrir aux dépens des pétioles.Les changements de galerie sont plus nombreux et la mortalité larvaire plus faible lorsque le déficit de saturation en eau du milieu ambiant est faible. Lorsque l'humidité relative est basse (HR=50–60%) la mortalíté larvaire est importante à l'intérieur des galeries d'origine et le nombre de changements est par conséquent limité.

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Summary The mining larvae of the celery fly, Philophylla heraclei, normally achieve their full development in a single mine inside a celery leaflet. If the amount of food is not sufficient, or in the case of a bad physiological condition of the leaflet (desiccation, celery leafspot, etc...), the larvae can leave their original mine and move to another leaflet to bore another mine.Such migrations can be induced experimentally by removing the larvae from their mine and placing them on another leaflet or leafstalk. They can also be induced by creating acute competition for food on celery plants offering a limited number of small leaves. In this case, larvae are frequently observed feeding on the tissues of the petiole of leaflets or the leafstalk, which behaviour is not observed in nature.There are few cases of migrations and larval mortality inside the leaf tissue is high (85%) when the humidity of the chamber is far removed from saturation (RH=50–60%). When humidity is near saturation (RH=95%), there are many cases of larval migration; about 50% of the larvae then reach the pupal stage, most of the larval mortality being due to the lack of utilisable vegetable tissue.In nature, this possibility of migration in a humid atmosphere enables the larvae of P. heraclei to resist competition and to escape leaf-spot which causes a rapid decrease in the amount of healthy utilisable tissue.

     

ÉTUDE AU LABORATOIRE DE LA RECHERCHE DU SITE DE TISSAGE DU COCON PAR LES LARVES DE CHRYSOPA PERLA (L.) (NEUROPTERA,CHRYSOPIDAE)

Résumé Les larves de Chrysopa perla lorsqu'elles sont prêtes à tisser leur cocon manifestent une tendance à descendre de leur support, recherchant secondairement untsite obscur et qui assure le contact. Lorsque le milieu est sect et meuble, elles s'enfouissent à une profondeur qui n'excède pas 20 mm dans la sciure. Les larves destinées à entrer en diapause s'enterrent plus profondément que celles qui ont un développement rapide continu. L'humidité excessive est un facteur répulsif énergique interdisant le plus souvent le tissage d'un cocon étanche. Lorsque le milieu ne permet pas l'enfouissement, les larves tissent successivement au contact les unes des autres, provoquant ainsi le regroupement des cocons.

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Summary The larvae of Ch. perla tended to leave their supports and look for a dark, thigmotactic place when ready to spin their cocoons (Table III). Darkness is not essential for spinning, successful pupation behaviour or for a low prenymphal mortality, under the light-intensity conditions used (3,000 lux). Under extremely wet conditions, the larvae did not easily find a place to spin their cocoons and may in fact return to their original support. In such conditions, the active larval stage for searching a suitable spinning place increased, the larva may die before a cocoon has been spun or an abnormal rough, porous, yellow cocoon may be made.Ideally a loose, dry substratum was chosen to spin the cocoon; the light substratum (sawdust and vermiculite) was always chosen in preference to the heavy one (earth and sand) and a dry substratum rather than a wet one (Table IV). In the light substratum, pupation took place in the upper 20 mm. In the heavy substratum, cocoons were spun on the surface and were adjacent to each other (Fig. 1) to allow support for the external threads. In both cases, substrate particles enclosed the cocoons.When the larvae were subjected to diapausing conditions by a short-day photoperiod, the mean weight of the cocoon was larger (14.21±1.83 mg) than if development was rapid and continuous (13.00±1.84 mg). Larvae which have been induced into diapause were found deeper in the sawdust than those which had not (Figs 2 and 3); but the difference was too small to be used as a method of separating the two populations.

     

DISTRIBUTION QUANTITATIVE DES DIVERS PHOSPHO-LIPIDES DANS LES NEURONES ET LES CELLULES GLIALES ISOLES DU CORTEX CEREBRAL DE RAT ADULTE

Resumé–— On décrit une méhode de préparation de neurones et de cellules gliales à partir du cortex cérébral, basée sur la dissociation du tissu à travers un tamis en nylon suivie ď une ultracentrifugation différentielle sur gradients de sucrose et de Ficoll.
On a dosé le DNA, ľazote protéque et les divers phospholipides. II ressort que le taux ď DNA par cellule est identique dans les neurones et les cellules gliales. Par contre, la quantité absolue ďazote protéique est 2.8 fois plus élevée dans les cellules gliales, celle des lipides totaux et des divers phospholipides 5-6 fois plus élevée.
La proportion de chacun des phospholipides dérminée par rapport aux phospholipides totaux est similaire dans les deux types cellulaires.     

ETUDE QUANTITATIVE PAR RADIOAUTOGRAPHIE AU MICROSCOPE ELECTRONIQUE DE L'UTILISATION DE LA DL-LEUCINE-3H PAR LES CELLULES DE L'HYPOPHYSE DU CANARD EN CULTURE ORGANOTYPIQE

The synthesis, intracellular transport, storing, and excretion of proteins by duck hypophyseal cells in organ culture were studied with tritiated DL-leucine and high resolution radioautography (pulse-labeling experiments). Quantitative study of the radioautographs allowed a determination of the relative proportions of cytoplasmic radioactivity located in each cellular compartment (ergastoplasm, Golgi apparatus, and protein granules) as well as the variations in these proportions as a function of time. The number of labeled protein granules as opposed to the total number of granules in the cell was also determined (RSg). These data were separately analyzed for the two types of cells present in the explants: prolactin cells and "MSH" cells. The synthetic process follows a course common to both cell types, each of which is distinguished by its particular modalities. The labeled proteins, synthesized within several minutes in the ergastoplasm, are concentrated in the Golgi zone within 30 min. They then migrate out of this area, the emptying of which is accomplished in about 4 hr. These proteins become equally distributed between the protein granules, on the one hand, and the cytoplasm ("sedentary" proteins), on the other. The RSg reaches its maximum when the Golgi zone is emptied, but this figure remains very low (3%). The RSg then decreases slowly (1% in 40 hr). It is concluded that hypophyseal cells are able to store protein in their granules and that their processes of synthesis and excretion are not continuous. The prolactin cells differ from the "MSH" cells in that they have a slower migration of newly synthesized proteins, and these proteins pass via the dilated ergastoplasmic cisterns in which they may possibly be stored.     

UNE FORME MICROTUBULAIRE ET PARACRISTALLINE DE RETICULUM ENDOPLASMIQUE DANS LES PHOTOCYTES DES ANNELIDES POLYNOINÆ

Luminous cells of polynoid worm elytra have been examined by methods of electron microscopy, with special attention focused on the fine structure of photogenic grains. These cells send apical prolongations into the mid-part of the elytra. The plasma membrane is very sinuous, and a special kind of desmosome links two portions of the same membrane. In addition to all the organelles which can be found in nonluminescent epithelial cells of the elytra, numerous photogenic grains are contained in their cytoplasm. These grains are composed of undulating microtubules measuring 200 A in diameter; their disposition in the grain is highly regular, and the grains appear as paracrystals. At the borders of the grains, the walls of the microtubules are often in continuity with those of the endoplasmic reticulum and with the external membrane of the nuclear envelope. Because of this fact, the microtubules of the grains may be considered a cytoplasmic organelle, representing a specialized form of the endoplasmic reticulum. The microtubules permit the repartition, inside and outside their walls, of two different products, one being forty-three times more abundant than the other; thus, the contact surface, in comparison to the volume, is greatly increased. The induction of the luminous reaction by change in the permeability of the microtubule walls, allowing contact between the two substances, is suggested as a working hypothesis. There is an evolution of the grains along the axis of the photocytes. The grains are often surrounded by progressively increasing amounts of glycogen. Their paracrystalline disposition is altered at the apex of the luminous cells.