Note sur un comportement particulier vis-a-vis des morts chezCoptotermes intermedius Silvestri (Isoptère Rhinotermitidae)

Sans résuméLaboratoire de Zoologie, Faculté des Sciences de Dakar, décembre 1966.     

Activités algologiques et limnologiques en France pendant l'année 1951

Sans résuméLaboratoire de Cryptogamie du Musuem National d'Histoire Naturelle de Paris     

Contribution a l'etude des groupements rupicoles endemiques des Alpes-Maritimes

Sans résuméReçue par la rédaction le 15-III-1949.Travail du Laboratoire d'Histoire naturelle de la Faculté de Médecine, (Montpellier) et de la S.I.G.M.A.     

Quelques organismes sporadiques du plancton de la région d'Amsterdam

Sans résuméLaboratoire du Service Medical et Sanitaire de la ville d'Amsterdam.     

Sur l'accumulation de nickel et de cobalt par les Charaées

Chara vulgaris was cultivated in a natural medium containing nickel and cobalt chloride.Growth increased in a culture solution containing Ni and Co in small amounts. Tissue analysis showed that the levels of Ni and Co in the dry matter were high. The two ions are found here as insoluble compounds, which explains why Chara vulgaris is an organism resistant to metal pollution.Université de Dijon, Laboratoire de Nutrition minérale des Végétaux     

Données sur la distribution des éléments biogènes dans l'estuaire du Tamar, à Plymouth

Résumé Le Tamar possède un estuaire à circulation d'eau typique (pas de mélange des eaux) mais présentant encore à ce point de vue, certaines particularités qu'il convient d'approfondir.Les quelques facteurs écologiques (température, transparence, salinité, phosphates et silicates) étudiés dans la zone la plus salée (de eu- à mésohaline) de l'estuaire montrent des variations importantes qui se réfléteront probablement dans la distribution du phytoplancton. La distribution des phosphates pose un certain nombre de problèmes et notamment celui de leur plus faible teneur en surface. Il conviendra de compléter cette étude préliminaire par des recherches sur la distribution des nitrates et l'exploration des zones oligohaline et limnétique.

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Summary A typical water circulation pattern (no mixing of fresh and sea waters) is demonstrated in the Tamar estuary, however a few particular points still are to be elucidated.The ecological factors (temperature, transparence, salinity, inorganic phosphate and silicate) studied in the lower reaches of the estuary show some important variations.It is emphasized that an exceptionally low amount of inorganic phosphate is found at the surface or the subsurface.

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Assistant au Laboratoire de Botanique systématique et Ecologie de l'Université Libre de Bruxelles. Boursier de l'U.N.E.S.C.O., stagiaire au Laboratoire de la Marine Biological Association of the U.K., Plymouth.     

Origin of enzymes involved in detoxification and root softening during cassava retting

The origin of root softening during cassava retting was investigated in a natural retting and in a sterile fermentation. Softening only occurred in the natural retting. Although high activities of endogenous pectin methyl esterase were found in cassava extracts from both fermentations, the depolymerizing enzymes polygalacturonase, active at low pH, and pectate lyase were only found in the non-sterile retting. No cellulase or xylanase activity was observed. The role of pectinases in the softening of cassava roots was confirmedin vitro using commericial enzymes. Root softening is therefore due to the combined action of endogenous pectin methyl esterase and exogenous bacterial depolymerizing enzymes. Detoxification occurred in both fermentations, confirming that the linamarase responsible for the destruction of cassava cyanide glycosides was mainly endogenous, even though microbial -glucosidases may help in the detoxication.F. Ampe is and A. Brauman was with the Laboratoire de Microbiologie et de Biotechnologie, ORSTOM, BP 181-Brazzaville, Congo. A. Brauman is now with the Laboratoire d'Ecophysiologie des Invertébrés, Université Paris XII, Avenue du Général De Gaulle, 94 010 Créteil, France     

Antisense transgenesis of tobacco with a flax pectin methylesterase affects pollen ornamentation

Summary. Antisense transgenesis of tobacco (Nicotiana tabacum) with a partial flax (Linum usitatissimum L.) pectin methylesterase (Lupme3) cDNA sequence yielded plants with altered pollen content. Moreover, the characteristically sculptured cell wall surrounding the pollen grains was modified in transgenic tobacco plants: the wavy ornamentation was dramatically reduced, suggesting the involvement of the demethylation of pectin in the pollen cell wall-specific structure. Germination of pollen was decreased and the pollen tube surface aspect was also different in transgenic plants.Correspondence and reprints: Laboratoire de Biotechnologies et Physiologie Végétales, Faculté des Sciences, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cedex, France.     

Infrastructure superficielle de la vésicule vitelline et du sac péricardique de l'embryon de Poecilia reticulata (Poisson Téléostéen)

Résumé Le microscope électronique à balayage montre l'existence d'un réseau complexe de microcrêtes à la surface de la vésicule vitelline et du sac péricardique de l'embryon de Poecilia reticulata. Cette étude permet également de préciser la localisation, l'aspect et la répartition des «cellules à chlorure» et de proposer un schéma tridimensionel de l'organisation infrastructurale de la paroi de la vésicule vitelline. Un choc osmotique détermine rapidement un mouvement d'étalement des cellules épithéliales sur la surface apicale libre des «cellules à chlorure». La signification de ces résultats est discutée en rapport avec le problème de l'osmorégulation embryonnaire chez les Poissons, en particulier chez les Cyprinodontes vivipares de la famille des Poeciliidae.

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Ultrastructure of the yolk sac and pericardial sac surface in the embryo of the teleost Poecilia reticulata

Summary A complex network of microridges is revealed by scanning electron microscopical examination of the yolk sac and embryonic pericardial sac surface of Poecilia reticulata. This study also specifies the localization, aspect and distribution of the chloride cells. A tridimensional diagram of the ultrastructural organization of the yolk sac wall is suggested. Osmotic stress quickly induces an overlapping of adjacent epithelial cells on the free apical surface of the chloride cells. These findings are discussed in relation to the problem of embryonic osmoregulation in fishes and especially in viviparous Poeciliids.

Nous exprimons notre gratitude à Mme Neumann, Directeur du Laboratoire de Micropaléontologie de l'Université Paris VI, qui nous a permis d'utiliser le microscope électronique à balayage qui a servi à cette étude. Nos remerciements s'adressent aussi à Melle Aubry et à M. Saussé pour leur concours technique. — Les observations en microscopie électronique en transmission ont été effectuées au Laboratoire de Microscopie électronique appliquée à la Biologie du C.N.R.S.     

Experimentation hyperbare (110 atmospheres) chez un crustace amphipode talitridae

Summary Males and females of the Amphipod crustacean Orchestia gammarella (Talitridae) in period of sexual activity were isolated and compressed in an experimental hyperbaric chamber at pressures between 20 and 110 ATA with oxygen-helium (héliox) mixture (PIo₂ = 300 torr). Stay duration under pressure was 16 days. This stay under pressure did not induce any important disorder like a high pressure nervous syndrome except excitement during compression between 70 and 110 ATA; phenomena of shedding of skin and reproduction did not change; rate of masculinity of the lineage was not modified. Slow decompression did not bring out bends.110 ATA pressure with heliox mixture does not appear to induce obvious deterioration neither in cellular metabolism nor in physiological functions for instance, the intricate functions of reproduction.

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Experimentation hyperbare (110 atmospheres) chez un crustace amphipode talitridae

Résumé Des crustacés Amphipodes Talitridae Orchestia gammarella (Pallas) en période d'activité sexuelle ont été isolés par couple et comprimés à des pressions de l'ordre de 20 à 110 ATA pendant 16 jours dans un caisson expérimental dont l'atmosphère était constituée par un mélange oxygène-hélium (PIo₂ = 300 torr). Ce séjour en pression n'a pas provoqué de signe majeur à rattacher au syndrome nerveux des hautes pressions, si ce n'est une agitation pendant la compression entre 70 et 110 ATA. Les phénomènes de mues et de reproduction n'ont pas été modifiés; le taux de masculinité de la descendance a été comparable à celui d'un groupe témoin. La vitesse de décompression choisie n'a pas entraîné d'accident. La pression de 110 ATA d'un mélange oxygène-hélium ne paraît donc pas entraîner d'altération majeure du méta-bolisme cellulaire et des grandes fonctions physiologiques parmi lesquelles les fonctions complexes de reproduction.

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Laboratoire de Sexualité et Reproduction des Invertébrés. Université Paris VI (Professeur H. Charniaux-Cotton)

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Laboratoire de Physiologie-U.E.R. Sciences Médicales Université de Bretagne Occidentale     

Reverberations and control of neural networks

Summary The simulation of neural networks, such as the brain cortex, which have a diffuse and rather uniform structure quite unlike the simple block-structure of extant computers, leads naturally to the study of functions and principles which only in part fall within the scope of Automata Theory. Systems of decision equations must be studied with a view especially to obtaining practical means for the prevision and computation of diffuse reverberations of wanted general characteristics, with the exclusion of all others. This amounts to deriving constraints on the allowed variability of the couplings among elements during learning processes, failing which the behavior of the simulator would become uncontrollable for practical purposes. A simple mathematical treatment is presented, which essentially linearizes these problems by an appropriate use of matrix algebra and permits a straightforward study of the wanted conditions, as well as of the controlling elements which may have to be added to the network.This work has been performed in part at the Laboratoire de Physique Théorique et Hautes Energies, Faculté des Sciences de Paris.This work has been performed with the joint sponsorship of the U.S.A.F. and their European Office of Aerospace Research under contracts no. AF EOAR 66-25 and AF 33(615)-2786.We wish to express our sincere thanks to Dr. F. Lauria for many illuminated discussions; and to Prof. M. Lévy for his kind hospitality at the Laboratoire de physique Théorique, in Paris, where part of this research was made.     

Action du CCC et de l'Amo 1618 sur la germination,la croissance et les activités AIA-oxydasique,peroxydasique, catalasique in vitro et in vivo de la racine de la Lentille

Summary Amo 1618 inhibits germination and root growth of Lentil seedlings in the dark and in the light, with some symptoms of toxicity; CCC has no effect.Both CCC and Amo 1618 inhibit the catalase activity of a lentil root extract.Increasing concentrations of Amo 1618 progressively increase the activity of peroxidase and IAA-oxidase in vivo; the catalase activity remains unchanged.The effect of Amo 1618 on root growth can thus be explained by a diminished auxin level mediated by an increased auxin catabolism.The effect of Amo 1618 and that of kinetin on root growth and enzymes are parallet. Gibberellic acid has an opposite effect on auxin catabolism.

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Une partie de ce travail a fait l'objet du mémoire de Licence de J. L. et a été réalisée au Laboratoire de Biochimie végétale de l'Institut de Botanique de Liège.     

Etude écologique comparée des populations d'ostracodes dans deux étangs de pisciculture en haute Belgique

The populations of Ostracods inhabiting two ponds have been studied. One of the ponds is left in its natural state and is of an oligotrophic type; the other one is fertilized once a year mainly with lime and calcium phosphate. Moreover the water feeding the last one is neutralized by a regular addition of calcium carbonate.Comparison of the densities of Ostracods shows that this fertilization has a positive action on the abundance of these crustaceans. Spatial distribution of the Ostracods is of the aggregative type. Specific composition is similar in both ponds but for some scarce species.Specific diversity suggests a higher organization level in communities inhabiting the natural pond. The diversity index H Of Shannon-Weaver shows a rather parallel seasonal fluctuation in both biotopes.

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Travail effectué au Laboratoire d'Hydrobiologie de l'Institut royal des Sciences naturelles de Belgique (Directeur de recherches G. Marlier) et au Laboratoire d'Ecologie générale et expérimentale de l'Université Catholique de Louvain (Professeur Ph. Lebrun).     

Effets du rubidium et du césium sur la croissance et la nutrition minerale des characees

Résumé Le rubidium et le césium introduits à l'état de chlorure dans le milieu de culture ont à faible dose un effet stimulant sur la croissance de Chara fragilis et de Chara vulgaris. La résistance de ces végétaux à l'action toxique des deux ions est accrue par l'addition de potassium au milieu.Les analyses chimiques confirment que le rubidium et le césium sont antagonistes vis-à-vis du potassium et du sodium alors qu'ils ne modifient pas de manière significative le taux de calcium.

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Chara fragilis and Chara vulgaris were cultivated in a natural medium containing rubidium and caesium as chloride.The growth of Characeae was increased after culture in the solutions containing Rb and Cs in small amount. The resistance to the toxic effects of these two ions is enhanced if potassium chloride is added to the medium.Quantitative analyses indicate that Rb and Cs decrease the rate of Na and K but have no significative influence on the rate of Ca.

Université de Dijon, Laboratoire de Nutrition minérale des Végétaux     

Antimicrobial susceptibility of non-O1 Vibrio cholerae isolated from wastewater stabilization ponds in Marrakesh,Morocco

The 365 strains of Vibrio cholerae, isolated in Marrakesh from raw sewage and stabilization pond effluent, were all identified as non-O1 Vibrio cholerae. When tested for their susceptibilities to ampicillin, amoxicillin, cephalothin, streptomycin, novobiocin, chloramphenicol, nalidixic acid and trimethoprim-sulphamethoxazole, 13% of the strains from raw sewage and 20% of those from stabilization pond effluent were found to be resistant to one or more of the antibiotics. There were no significant differences, in terms of drug resistance, between isolates from the new sewage and those from the ponds' effluent.The authors are with the Université Cadi Ayyad, Faculté des Sciences Semialia, Département de Biologie, Laboratoire de Microbiologie, BP S/15, Marrakesh, Morocco     

Ontogenèse de l'innervation des organes sensoriels des antennes chezReticulitermes lucifugus santonensis Feyt.

Summary The author has studied the ontogenesis of the innervation of neurosensorial organs on the antennæ ofReticulitermes lucifugus santonensis Feyt. She has found, among the organs with external processussensilla trichoidea (small, medium an big),sensilla basiconica, andsensilla campaniformia. Repartition and variation in number of sensilla during developpement have been described. She describe so 3 sensorial organs without any external processus: 2 chordotonal organs (one in the scapus, the other in the pedicellus). Antennal nerves and tracheas have been followed.

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Je tiens à exprimer toute ma reconnaissance à M. lePr Richard, pour m'avoir invitée dans son Laboratoire et pour l'intérêt qu'il a porté à mon travail Je remercie très vivement tous mes amis du Laboratoire de Biologie Animale qui m'ont aidée dans cette étude.     

The common inhibitory neuron innervates every leg muscle in crabs

Summary The muscles proximal to the autotomy plane in the walking legs of two crab species,Eriphia spinifrons andCarcinus maenas, are innervated by the common inhibitory neuron (CI). Thus, CI is truly common to all 11 leg muscles. It is suggested that CI has the essential function in all leg muscles of preventing the tonic muscle fibers from participating in rapid contraction and relaxation cycles during walking.Abbreviation CI common inhibitory neuron On leave of absence from: Laboratoire de Neurobiologie Comparée, C.N.R.S. Université de Bordeaux I, Place du Docteur Bertrand Peyneau, F-33120 Arcachon, France     

POPULATION STRUCTURE OF BIOMPHALARIA GLABRATA, INTERMEDIATE SNAIL HOST OF SCHISTOSOMA MANSONI IN GUADELOUPE ISLAND, USING RAPD MARKERS

Nine populations of the snail Biomphalaria glabrata, sampledin 1992 and in 1994 in the Guadeloupean focus of schistosomiasis,were studied using random amplified polymorphic DNA (RAPD) markers.The detected polymorphism was low with 11 polymorphic markers.A canonical analysis of the genetic polymorphism showed a significantand large differentiation between the nine populations studiedin a restricted area of 45 km². A Mantel t–test indicateda significant correlation between the genetic differentiationand the geographical distance. A significant but smaller differentiationbetween a northern and southern group was also observed usingcanonical analysis. A comparison over time has been done. Corresponding author: A. Théron. Laboratoire de Biologie Animale,UMR 5555 CNRS, Centre de Biologie et d'Ecologie Tropicale et Méditerranéenne,Université, 52 Av. de Villeneuve, 66860 Perpignan Cedex,France. Tel: +33 4 68 66 21 83 Fax: +33 4 68 66 22 81 E-mail:theron{at}univ-perp.fr (Received 26 October 1998; accepted 30 December 1998)     

Use of 5,6-dichloro-l-β-D-ribofuranosylbenzimidazole to distinguish light stimulation from cytokinin stimulation of amaranthin synthesis in Amaranthus tricolor

In Amaranthus tricolor seedlings, amaranthin synthesis can be induced by cytokinins and (or) by light. It was found that 5,6-dichloro-1--D-ribofuranosylbenzimidazole (DRB) was a specific inhibitor of the cytokinin response whereas the light response was unchanged. DRB also inhibited the negative response of pigment production to an anticytokinin, 7-(pentylamino)-3-methylpyrazolo(4,3-d) pyrimidine (PAMPP).DRB can be considered as a specific inhibitor of the physiological responses to cytokinins. The evolution of the inhibition percentage versus cytokinin or anticytokinin concentration shows that DRB is not a `competitor' of cytokinins.The experiments suggest that cytokinins or anticytokinins act as modulators of a fundamental light activated reaction of amaranthin synthesis.Address where proofs should be sent: Laboratoire de Physiologie végétale, Faculté des Sciences et des Techniques, Université de Nice, F-06034 Nice Cedex, France