Étude de l'effet de la température sur la division des cellules séparées de feuilles deCalystegia sepium (L.) R.Br.

Cells mechanically isolated from homogenized leaves ofC. sepium dividein vitro. The rate of cell division is strongly influenced by temperature with the optimum between 31 and 34 °C. The rate of cell division increases proportionally with a rise in temperature up to 31 °C and is accompanied by a reduction in the length of the preparatory phase of the division. A supraoptimal temperature (40 °C) inhibits or stops the cell division which can be restored provided that the cells are transferred to 31 °C. If the preparatory phase to the commencement of cell division is accomplished at 17 °C the cells then exposed to 31 °C divide more rapidly than if they are exposed directly to 31 °C.     

Mise en évidence par immunofluorescence des cellules sécrétrices de glucagon dans le pancréas endocrine du poisson téléostéen Xiphophorus helleri H.

Summary The ruthenium red staining of the surface coats was studied in the adrenal medullary cells of golden hamster. Both immersion and perfusion fixation was used with the ruthenium red containing fixative, however, only the perfusion fixation gave positive results. A rather thick electron dense ruthenium red positive layer was found on the plasma membrane of the endothelial cells, around the capillaries in the basal lamina, in the basement membrane of the chromaffin cells as well as on the apical and lateral cell surfaces of the adrenomedullary cells. Coated pits and coated vesicles usually showed an intensive ruthenium red staining, but the other cell components in the cytoplasm did not. On the basis of these observations author suggests that the ruthenium red positive material corresponds to acidic mucopolysaccharides in the hamster adrenal medulla, and its wide-ranging occurrence is indicative of its significance in the secretion process of catecholamines.Wellcome Research Fellow.     

Étude anatomique et comparative de charbons de bois de Larix decidua Mill. et de Picea abies (L.) Karst

The anatomical criteria for the identification of the genera Larix and Picea defined on wood samples by Bartholin (1979) and Anagnost et al. (1994) have been tested on charcoal in order to permit a taxonomic discrimination between two European alpine species, Lark decidua Mill. and Picea abies (L.) Karst. Examination under an episcopic microscope with a high magnification (× 1 000) of the bordered pits of the ray tracheid walls, the only really discriminating criterion, shows a new type of indented pit. This makes it possible to identify the two species more accurately. Thus, these two species can now be distinguished on charcoal instead of only on wood. However, this distinction remains uncertain if the fragment size is under 1 mm, which is often the case in pedoanthracological samples from high altitude soils.     

Contribution à l'étude ultrastructurale des cellules interrénales de Salamandra salamandra L. (Amphibien Urodèle)

Summary The interrenal (adrenocortical) cells of spotted Salamanders seriously affected by a mycotic disease for a long period, have a strikingly large dimension. Their nuclei and nucleoli show a marked hypertrophy. The cytoplasm is sometimes completely deprived of liposomes; it is very rich in mitochondria, smooth-surfaced reticular tubules and free ribosomes. Ergastoplasmic cisternae are frequently encountered in the vicinity of the nuclei. The Golgi apparatus is considerably developed. This organisation, which is common to all the cells, characterizes a stage of intense activity of hormonal synthesis, probably induced by high levels of ACTH. Beside these typical features, small dense bodies are particularly abundant at the periphery of the cells. No mitotic division could be seen.In Salamanders which suffer only moderately from the disease, the cells of the central part of the interrenal islets are the only ones to show the characteristics of great activity. On the other hand it can be noted that such cells are the more numerous the more the situation of the islet is cranial. As opposed to this, the cells of the periphery of the islets show only signs of a poor activity.During the extension of the disease, the number of highly active cells increases progressively, probably as a consequence of the activation of the peripheral cells. This activation usually begins with the hypertrophy of the nucleus and the nucleolus. The cytoplasmic modifications (namely the lipid depletion and the apparition of numerous dense bodies in the vicinity of the Golgi apparatus) seem to appear during a second stage only.

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Zusammenfassung Die Interrenalzellen von Feuersalamandern, welche seit längerer Zeit an einer Pilzkrankheit schwer leiden, zeigen einen ungewöhnlich großen Durchmesser. Ihre Zellkerne samt Nukleoli sind überentwickelt. Das Zytoplasma ist hie und da frei von Liposomen, zeigt aber überaus zahlreiche Mitochondrien, glatte Tubuli des endoplasmatischen Retikulums und freie Ribosomen. In der Nähe des Zellkerns trifft man häufig ergastoplasmatische Zisternen an. Der Golgi-Apparat ist stark ausgebildet. Diese Organisation, die man in allen Zellen wiederfindet, deutet auf eine starke Aktivität der Hormonsynthese hin, die wahrscheinlich unter dem Einfluß von hohem und andauerndem ACTH-Gehalt steht. Ferner findet man kleine elektronendichte Körper, vor allem häufig an der Peripherie der Zellen. Mitotische Zellteilungen wurden nicht beobachtet.Bei Salamandern, die von der Erkrankung weniger befallen waren, zeigen nur die inneren Zellen der Interrenalinseln Äquivalente einer starken Aktivität. Sie sind im übrigen desto zahlreicher, je weiter cranial die Interrenalinsel liegt. Die Zellen in der Peripherie dagegen tragen die Merkmale einer schwachen Aktivität.Im Laufe der Krankheit nimmt die Zahl der hochaktiven Zellen fortwährend zu, wahrscheinlich infolge der Aktivierung der Zellen der Peripherie. Diese Aktivierung beginnt mit der Vergrößerung der Zellkerne und Nukleoli. Die zytoplasmatischen Veränderungen, insbesondere das Verschwinden der Liposomen und das Erscheinen von elektronendichten Körpern in der Nachbarschaft des Golgi-Apparates, scheinen in einer zweiten Phase aufzutreten.

     

Modélisation de l'impact des mollusques cultivés sur la biomasse phytoplanctonique de l'étang de Thau (France)

A model coupling a 2D transport equation and a simple model of the nitrogen cycling was developed for the Thau lagoon (France). The model took into account the wind forcing on the hydrodynamism, the effect of the temperature on the biological processes, the input of the watershed area, the light dependence of the pelagic primary production and the prédation of the phytoplankton by the cultivated filter feeders. The model ran under two steady-state situations of wind with constant temperature and light values corresponding to spring weather conditions. Simulations showed that the biological flows were very sensitive to the wind. The budget of the nitrogen flows were computed for the three areas devoted to the filter feeder cultivation and the results highlighted the impact of cultivated oysters as a source of nutrients and an important nitrogen flow through the predation of phytoplankton.     

Notes sur l'écologie et l'éthologie des espèces du genreLasius (Hymenoptera Formicid≸)

Summary Among species of the Ant genusLasius, nests sites and nesting habits differ according to the ecological requirements of every species. A classification of these habits has been outlined taking into consideration the complexity of the building techniques and the nature of the building materials. Whithin one single species there are populations differeing under these respects. This suggests the occurence of biological races.

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Zusammenfassung Beobachtungen über die Lage und die Struktur des Nestbaues bei dem GeschlechtLasius in natürlichem Milieu, erlaubte es genau definierte oekologische Ansprüche festzustellen. Eine Einteilkung der artspeziefischen Sitten des GeschlechtesLasius konnte an Hand der angwendten komplessen Bauart kund des gebrauchten Materials aufgestellt werden. In einer gegebenen Art können jedoch mehrere Völker miteinbegriffen sein die sich durch einen verschiedenartigen nestbau unterscheiden; dies lässt uns annehmen, dass wir vor verschiedenen biologischen Rassen stehen.

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Notes sur l'écologie et l'éthologie des espèces du genreLasius (Hymenoptera Formicid)

Résumé L'observation de l'emplacement et du mode de nidification des espèces du genreLasius dans leur milieu naturel a permis de mettre en évidence des exigences écologiques bien définies. De même, la complexité des techniques mises en uvre et le type de matérian employé lors de la construction des nids permettent de présenter un classement des murs des espèces du genreLasius. Une même espèce comporte des populations caractérisées par un mode de nidification différent, ce qui incite à penser que nous sommes en présence de races biologiques différentes.

     

Effets de la marée noire de l' ”Amoco Cadiz ” sur le benthos sublittoral du nord de la Bretagne

Effects of the “Amoco Cadiz ” oil spill on the sublittoral benthos, north of Brittany. Effects of hydrocarbons on the sublittoral macrobenthic communities have been observed through (1) studies of population dynamics of selected communities, conducted prior to the spill by the tanker “Amoco Cadiz ” in spring 1978 and (2) comparisons between the situation in summer 1978 with that in earlier years, with continuation of the observations in some selected sites. The effect of the spill has been selective, involving a limited number of species, mainly crustaceans, molluscs and the sand-urchinEchinocardium cordatum. The spill mainly affected communities on fine sediments and, to a lesser degree, those on mixed sediments. Notably, the destruction of the dominant populations ofAmpelisca, in areas of fine sands in the Bay of Morlaix, has led to a marked decrease of biomass and production. Moreover, repopulation will be difficult because of the isolation of such communities on the southern side of the English Channel. The effects evolved with time; after a phase of sharp and selective mortality, which did not last more than a few weeks, secondary effects on the recruitment of the remaining species do not seem to have occurred on a large scale. Nevertheless, a proliferation of polychaetes has been noticed.      

Observations sur le mécanisme de l'agglutination sérique des microbes. (Phénomène de Charrin et Roger.)

Conclusion L'hypothèse que nous venons d'esquisser n'est certainement pas une généralisation définitive et elle devra subir de nombreuses retouches avant de pouvoir englober tous les faits connus, mais n'est ce pas là le propre de toutes les généralisations à leur début?Actuellement la théorie du potentiel-force d'attraction et de l'adsorption orientée a le gros avantage d'expliquer la plus grande partie des faits bien établis, ce qui constitue un progrès incontestable et très précieux.     

Impact probable du volcanisme sur le décès des Hominidés de Dmanissi

The human remains unearthed at the Lower Pleistocene site of Dmanisi (Georgia), are numerous, well preserved and show no evidence of transportation or predation. They were discovered over a small surface and correspond to at least five Homo georgicus individuals, whose age at death is regularly distributed from the teenager to the elder over 40 years old. These characteristics evoke a family group who died suddenly. Granulometry and chemical analyses of ca. 30 volcanic tephra samples prove its unicity and its primary position. Since this tephra cannot correspond to a nuée ardente, it is probable that the Dmanisi Hominids were surprised and asphyxiated, 1 810 000 years ago, by volcanic ashfalls.     

Ultrastructure de l'épithélium tégumentaire de Glossiphonia complanata (L.) (Hirudinée): cellules épithéliales et organes sensoriels de Bayer

Résumé Le tégument de Glossiphonia complanata comprend, outre les cellules épithéliales banales, de nombreux organes particuliers ou organes de Bayer, regroupés essentiellement sur la face dorsale de l'animal. Ils sont formés par une cellule apicale saillante enchassée dans une cellule musculaire en anneau.L'ensemble de ces formations est étudié du point de vue ultrastructural. Des cellules épithéliales partent des fibres nerveuses afférentes, sans doute vecteur des perceptions de stimuli mécaniques de pression au niveau du tégument; la réponse se faisant sans doute par la contraction de la cellule basale de chaque organe de Bayer, innervée par des fibres nerveuses efférentes, entrainant la saillie de la cellule apicale. Le hérissement de ces nombreuses papilles du tégument dorsal pourrait être un signal perçu par le partenaire sexuel, chez cette Hirudinée à fécondation hypodermique.

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Ultrastructure of the integumentary epithelium of Glossiphonia complanata (L.) (hirudinea): Epithelial cells and sensory organs of bayer

Summary The integument of Glossiphonia complanata, built up by epithelial cells, contains numerous particular organs (Bayer organs), mainly on the dorsal side of the animal. They consist of a protuberant apical cell, which is surrounded by a ring-shaped muscle cell. All the integumentary formations are studied from an ultrastructural point of view. From the epithelial cells issue afferent nerve fibres, considered as vectors of the perception of mechanical stimuli of pressure at the level of the integument; the response no doubt operating by the contraction of the basal muscle cell of each Bayer organ, innervated by efferent nerve fibres, bringing forth the protrusion of the apical cell. The erection of these numerous papillae of the dorsal integument might be a signal perceived by the sexual partner, fecundation occurring in this group of leeches under the integument.

     

Utilité de l'épreuve d'effort sur tapis roulant peu après un infarctus du myocarde.

A program of reconditioning through walking was prescribed for 130 patients following an exercise test on a treadmill 3 weeks after a myocardial infarction. At 8 and at 12 weeks the patients again underwent an exercise test. The protocol is safe and permits the detection of angina, arrhythmias and dyspnea during the exercise, thus avoiding delays in treatment. The heart rate and the systolic blood pressure were measured at the end of each stage of the test and after 3 minutes of recuperation. About 75% of the patients attained the target energy output of the two submaximal tests (4 and 7 mets at 3 and 8 weeks respectively); an output of 7 mets permits a patient to resume his or her usual daily activities. The results of the tests at 3 and 12 weeks (the latter a maximal test) showed that the probability of an aerobic capacity of 7 mets or greater at 12 weeks is 86% if the 3-week test is completed. Clinical observations alone did not have the same prognostic value 3 weeks after the infarction.     

Étude paléontologique du genre Sabinia (Rudiste à canaux)des récifs du Campanien de Tunisie

Campanian rudist reefs of Central Tunisia are rich in pallial-canal rudists, belonging to the genus Sabinia. The Djebel Serraguia layer shows well-preserved samples allowing to make a detailed paleontologic study. A new sub species of a previously observed species from the Maastrichtian of Yugoslavia and Turkey is described. Identified for the first time on the african margins, this new taxon gives interesting data concerning systematic and evolution of the genus Sabinia, as well as the relationships between reef provinces during the Upper Senonian. The biosedimentologic role of Sabinia within tunisian reefs is pointed out.     

Effets de divers facteurs de croissance (FGF,IGF-1) sur les ébauches des membres de l'embryon d'orvet (Anguis fragilis L.)

The present experiments were carried to investigate the effects of some growth factors (FGFs, IGF-1) on the development of limb buds in the slow-worm (Anguis fragilis L.). This serpentiform reptile is devoid of legs in adulthood; but anlagen of limbs appear during embryonic life; their existence is only temporary: their growth ceases, they regress and disappear before hatching. Treatment of embryos was performed either by injection of the drugs around the limb buds or by application of small fragments of cellulosic paper soaked in the growth factors. The embryos were treated (27 by injection, 24 by application of cellulosic paper) at the stage of the allantoic bud 0.2 mm to 0.5 mm long and at an older stage (allantoic bud 1.8 mm to 4 mm long) (21 embryos treated). The administered growth factors were FGF-2, FGF-4 and IGF-1. Dosages were around 1 000 to 3 900 ng. Anterior limb buds display only very weak sensitivity to the effect of the applied growth factors: only a small proportion of the treated embryos presented a weak hypertrophy of these buds; however, after application of a fragment of cellulosic paper soaked in FGF-2, two thickening of the somatopleure in a embryo and two salient buds in another developed in the territory of the limb, propably representing anlagen of supernumerary limbs. In 25% of the embryos treated at the stage of the allantoic bud 1.8 to 4 mm long, the anlagen of the posterior limbs were greatly stimulated under the action of FGFs and IGF-1: the volume of the treated limbs was several times greater than the one of control limbs; histological study showed in the hypertrophied buds, numerous mitoses in the mesoblast and an apical ridge which did not degenerate. These results are in agreement with previous experiments and they show that it is possible to check experimentally the evolutive regression of the limbs of Anguis embryos.     

Ultrastructure,innervation et fonction de l'épiphyse de l'orvet (Anguis fragilis L.)

Summary The pineal organ of Anguis fragilis contains two essential cell types: pinealocytes and interstitial cells. The scarce outer segments are of different appearance; they show cyclic degenerative changes. Only one intraepithelial ganglion cell has been identified in the material of this study. Although an intracommissural pineal nerve is present, the absence of synaptic junctions of pinealocytes with ganglion cells indicates a loss of photosensory function. Three kinds of vesicles (also dense-core vesicles) originating from Golgi complex are described in the pinealocytes. These secretory vesicles show a vascular polarity. The pinealocyte processes extend to the basement membrane. Secretory material is released into the peripineal space. Efferent sympathetic nerve fibers are described near the pineal epithelium. The nerve endings of these fibers contain three types of vesicles. It is suggested that the pineal organ of Anguis fragilis has a well established secretory function.

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Zusammenfassung Die Epiphysis cerebri von Anguis fragilis enthält zwei wesentliche Zelltypen: Pinealocyten und Zwischenzellen. Die Außenglieder, die nur selten vorkommen, sind verschiedenartig gestaltet und erleiden einen zyklischen Degenerationsprozeß. Im Pinealepithel ließ sich nur eine einzige Ganglienzelle mit Sicherheit nachweisen. Obwohl eine intracommissurale Nervenbahn vorhanden ist, spricht das Fehlen von Synapsen zwischen Pinealocyten und Ganglienzellen für einen Schwund der Lichtsinnesfunktion. In den Pinealocyten werden drei aus dem Golgiapparat stammende Bläschenarten, darunter auch solche mit einem elektronendichtem Inhalt (Granula), beschrieben. Diese Sekretbläschen sind polar auf die Blutgefäße ausgerichtet. Fortsätze der Pinealocyten stehen mit der Basallamina in Verbindung; allem Anschein nach werden hier Substanzen in den periepiphysären Raum abgegeben. Efferente sympathische Nervenfasern sind in der Nähe des Epiphysenepithels zu beobachten. Die Endigungen dieser Fasern enthalten drei verschiedene Bläschentypen. Die Epiphyse der Blindschleiche scheint eine sekretorische Funktion zu haben.

     

Le Genisteto-Carlinetum macrocephalae ass. nov. de l'étage montagnard et le Ligusticetum corsici ass. nov. de l'étage subalpin des Massifs du Cinto et du Campotile orientale

Sans résuméJe tiens à remercier M. le Dr.J. Braun-Blanquet de la généreuse hospitalité qu'il m'a offerte à la S.I.G.M.A. et des précieux conseils qu'il m'a dispensés pour la définition de ces associations. C'est la raison pour laquelle il m'a paru nécessaire de l'associer à l'une des Associations originales que j'ai décrites.Je suis également reconnaissant à mes amisM. et G. Roux d'avoir permis le traitement de mes données floristiques par l'analyse factorielle des correspondances.     

Rupture de la diapause ovarienne d'Anacridium aegyptium par stimulation électrique des cellules neurosécrétrices médianes de la pars intercerebralis

Oögenesis and the physiological activity of the corpora allata were studied in adult females of the Egyptian locust (Anacridium aegyptium), in ovarian diapause, after electrical stimulation in vivo of the pars intercerebralis. This stimulation provokes (1) a decrease in the quantity of fuchsinophilic material present in the median neurosecretory cell bodies and in the internal cardiac tract, (2) an increase in the physiological activity of the corpora allata (measured by its chromatropic effect on larvae of Locusta), and (3) rupture of the ovarian diapause (advance of maturation of the oöcytes and oviposition by 5 months, and initiation of the ovarian cycle).In the control animals, the same electrical stimulations of various regions of the central nervous system (tritocerebrum, first ganglion of the abdominal cord) have no effect on these phenomena.In allatectomized females, electrical stimulations of the pars intercerebralis are followed by a slight growth of oöcytes, without a deposit of yellow vitellus. The diapause is not broken. Section of the allatocardiac nerves or rupture of the allatocardiac and allato-suboesophageal nervous connexions do not change the physiological state of the corpora allata. In the case of females in which the corpora allata have been disconnected, electrical stimulations of the pars intercerebralis succeed in activating the corpora allata and breaking the ovarian diapause. The aggregate of these results confirms that in locusts the control of the brain over the physiological activity of the corpora allata is above all neuroendocrine.     

Emission of hydrogen sulfide by twigs of coniferes — acomparison of Norway spruce (Picea abies (L.) Karst.), Scotch pine (Pinus sylvestris L.) and Blue spruce (Picea pungens Engelm.)

The emission of reduced volatile sulfur compounds from twigs of Norway spruce (Picea abies (L.) Karst.) was measured in the field by cryosampling and gaschromatographic analysis. Trees were growing in the Erzgebirge (E-Germany) at Oberbärenburg and at the Kahleberg and at a third stand in NW-Bavaria (S-Germany). Emission rates were also measured for Scotch pine (Pinus sylvestris L.) and Blue spruce (Picea pungens Engelm.) at the Kahleberg. Twigs still attached to the trees were enclosed in a flow-through gas exchange cuvette. H₂S was detected as the predominant reduced sulfur compound emitted from the twigs. The mean H₂S emission rate from twigs of Norway spruce varied between 0.04 pmol kg^-1 dw s^-1 at Würzburg and 6.21 pmol kg^-1 dw s^-1 at the Kahleberg. Comparing different species at the Kahleberg, the mean H₂S emission rate was almost the same from twigs of Norway spruce (6.2 pmol kg^-1 dw s^-1) and Blue Spruce trees (5.9 pmol kg^-1 dw s^-1) but it was approximately 18 times higher for Scotch pine (110 pmol kg^-1 dw s^-1). The percentage of SO₂-exclusion via H₂S-emission of the tree species investigated at the Kahleberg is calculated on the basis of data on SO₂ fluxes. It is very small for Norway spruce and Blue spruce. However, for Scotch pine, H₂S emission contributes about 10% to the detoxification of SO₂.