Contributions à la biochimie du ver à soie—XXX. Biosynthèse de tréhalose et de glycogène à partir de glucose-1-phosphate

• 1.1. When injected into silkworms in the middle of the fifth larval instar, labelled G-1-P is principally used for the synthesis of hemolymph trehalose.
• 2.2. Glycogen synthesis from the same source in the fat body proceeds more rapidly in undernourished larvae than in those fed normally.
• 3.3. Owing to the poor incorporation of the radioactivity in the glycogen and especially in the trehalose of the fat body, it is suggested that the trehalose could be synthesized from pyruvate elsewhere than in the fat body, and that the biosynthetic pathway of trehalose from pyruvate does not necessarily pass through glycogen.
• 4.4. The synthesis of trehalose and glycogen, as well as the hydrolysis of glycogen, could be controlled, directly or indirectly, by the variations of the trehalose level in the hemolymph.
• 5.5. The gluconeogenetic pathways in the silkworm are discussed and presented in the form of a partially hypothetical figure.

     

Apports de la palynologie a la connaissance du Pliocène du Roussillon (sud de la France)

The present study illustrates clearly how pollen analysis may be applied to stratigraphy from a botanical point of view. Within a chronologically reliable frame (Middle Pliocene for the marine deposits on the basis of Foraminifera record; two subzones for continental deposits on the basis of Mammals record: Hautimagne for Terrats fauna, Sète for Serrat-d'en-Vacquer fauna), palynology provides a good stratigraphical boundary: the extinction of the Taxodiaceae. In a remblayage area, it is established that a continental level is not necessarily younger than a marine one unless they are superposed. Many profiles are replaced according to the «progradation of the pliocene gulf of Roussillon. The boundary between marine and continental deposits cuts through the chronological line of the Taxodiaceae extinction. The flora investigated (93 taxa) is the first known for the Pliocene of this area. The extinction of the Taxodiaceae in southern France has a climatic cause: the setting in of a mediterranean rhythm (dry summers). This extinction is much older than the one which took place in Italy (Tiberian boundary) and in the Netherlands (Reuverian-Pretiglian boundary).     

Une nouvelle espèce du genre Bohlinia (Mammalia,Giraffidae) du Miocène supérieur de Toros-Menalla,Tchad

New Giraffidae specimens discovered from the Late Miocene fossiliferous sector of Toros-Menalla (northern Chad) are described. These specimens are assigned to Bohlinia, a genus known so far only in some Late Miocene localities of Eurasia. This is the first occurrence of the genus in Africa. Analysis of the material allows us to describe a new species of giraffid, Bohlinia adoumi n. sp., probably close to the Eurasian forms.     

Espèces du groupe de Candona candida,Candona neglecta et quelques Candona à l'aspect morphologique problématique (Candonidae,Ostracoda) du Bassin de Turiec (Miocène supérieur,Slovaquie)

The subfamily Candoninae is the most diversified group in the Upper Miocene freshwater deposits of the Turiec Basin (Slovakia). The presence of Candoninae morphologically related to recent as well as Central Paratethys species reveals a problem between taxonomy based on soft body (zoological classification) and taxonomy based on hard part (paleontological classification). The current zoological classification is applied which reflects the real taxonomical relationships between species. The accent was put on the carapace morphological details to distinguish the species. Three described groups (Candona candida, C. neglecta and Candona of group indet) contain 7 new species – Candona densa, C. mocki, C. imaginaria, C. margueritae, C. singularis, C. sirveni et C. vahica.     

Effet de la température sur la structure du fibrinogène

The variation of temperature from 5 to 37° produces a perturbation of the ultraviolet spectrum of fibrinogen arising from the tyrosine and tryptophan residues, but does not change the value of its specific rotation. The phenomenon is reversible, its half-transition temperature is equal to 21°. The light-scattering studies show that a dissociation of fibrinogen occurs at 37° giving a molecular weight of 190 000 for the fibrinogen subunit. By lowering the temperature, there is polymerization. The results of the analytical ultracentrifugation confirm the dissociation of the molecule into subunits, but cannot demonstrate the presence of monomer-dimer equilibrium.     

Joseph-Pierre Pétrequin (1809–1876): chirurgien, anatomiste, historien de la médecine, fondateur de la Faculté médicale lyonnaise et son procédé chirurgical original pour la cure de la gangrène de la verge

Pétrequin was an outstanding anatomist, surgeon, medical historian, and founder of the Lyon School of Medicine. This article describes his scientific contribution with particular emphasis on his original surgical procedure for the treatment of penile gangrene.     

Approche cognitivo-comportementale de l’addiction à la cocaïne

Cocaine addiction has medical, psychological, cognitive, social, and legal consequences. For a while confined to a targeted audience, epidemiological data show that cocaine addiction considerably “increases” in Europe and reaches all social categories, including socialized people. The cognitive-behavioral approach provides a conceptual frame allowing a better understanding of the mechanisms involved in at the beginning and all along the cocaine addiction. Consumption and addiction to cocaine are then considered learned behaviors. Cognitive-behavioral therapies applied to the treatment of cocaine addiction include different therapeutic techniques that modify maladjusted behaviors, thoughts, and feelings leading to consumption. On a pharmacologic point of view, there is no drug treatment for this disorder, even though promising tracks emerged, especially the N-acétylcystéine.     

Influence de l'âge de la culture sur la survie de Rhizobium meliloti à la lyophilisation et à la conservation après lyophilisation

Summary Survival after freeze drying of Rhizobium meliloti grown on different media was higher in young cultures when cells were in their logarithmic phase than in the old which were in their stationary phase. On the contrary the ability of the freeze dried organisms to survive during storage at 30°C was better for cells from old cultures than from young ones.     

Une nouvelle espèce d'Apodemus (Rodentia,Mammalia)du Pliocène de la dépression de Guadix-Baza (Grenade,Espagne)

This paper describes a new species of Apodemus,A. agustii, a Middle Pliocene Muridae from the Guadix-Baza basin. Its morphology is far from that postulated as more frequent in Apodemus: its molars crowns are relatively high: there is no connection between t6 and t9 in M¹ and M². Taking in account this and its age, it is placed in an evolutionary branch, convergent with “Rhagapodemus” morphotype.     

Effet du rayonnement solaire sur la persistance des conidiospores de L'hyphomycète entomopathogène,Nomuraea rileyi, à la surface d'un couvert végétal

Résumé La persistance des conidiospores deNomuraea rileyi (F.) Samson à la surface du couvert végétal a été étudiéein situ en culture de féverole (?Féverole 1 et 2?) et de chou. L'effet du rayonnement solaire sur la survie du germe a été analysé, d'une part, dans des microparcelles recouvertes d'écrans sélectifs arrêtant les radiations de longueurs d'onde inférieures à 320 nm (UV A⁺) ou à 400 nm (UV⁻) ou par un écran total vis-à-vis du rayonnement direct (RYT⁻) et, d'autre part, dans une microparcelle découverte (RYT⁺). Les conditions microclimatiques ont été suivies pendant toute la durée des expérimentations et le contr?le de l'activité résiduelle du champignon a porté essentiellement sur le dénombrement des spores viables sur milieu nutritif après mise en suspension d'un broyat des échantillons de feuilles prélevés sur le terrain. Dans le cas des variantes expérimentales (RYT⁺) et (RYT⁻) le potentiel infectieux a été éprouvé sur des larves deSpodoptera littoralis Boisd. (Lépidoptère Noctuidae) alimentées pendant 24 h avec des rondelles de feuilles recueillies dans le couvert. La durée de demi-vie de l'inoculum sporal est étroitement liée à l'ensoleillement; par temps clair elle peut atteindre un minimum de 3,6 h (?Féverole 1?), alors que dans les microparcelles totalement protégées du rayonnement direct, elle est supérieure à 40 h. Les données d'activité pathogène confirment l'inactivation de l'inoculum soumis au rayonnement solaire. Parallèlement, le recours aux écrans transparents (UV A⁺) ou opaques (UV⁻) au proche ultra-violet (320–400 nm) a permis de démontrer clairement l'effet léthal de l'UV A naturel sur les conidiospores deN. rileyi, dont les demi-vies peuvent être réduites jusqu'à 4 fois (?Féverole 1?: X_{UV A} +=11,6 h au lieu de X_UV−=48,2 h). A partir de ces résultats, on estime que par temps ensoleillé en été, le potentiel d'inoculum deN. rileyi exposé au rayonnement solaire direct peut chuter de 10⁴ fois en une semaine, alors que par temps couvert cette réduction n'aurait été que de 100 fois. Avec la collaboration technique deH. Vermeil de Conchard.     

Cinétique de la biosynthèse induite de l'iso-1-cytochrome c et de l'iso-2-cytochrome c au cours de l'adaptation à l'oxygène

A method is described for a quantitative extraction, separation and determination of two distinct molecular species of cytochrome c from yeast: iso-1-cytochrome c and iso-2-cytochrome c. This method is applicable, with an overall yield of about 90 %, to small quantities of yeast (about 2 g) and small quantities of cytochrome c (about 5 mμmoles).The time course of biosyntheses of two isocytochromes c was simultaneously studied during induction by O₂ and found different. Immediately upon admission of O₂ there was a rapid formation of iso-2-cytochrome c followed by a deceleration, while the formation of iso-1-cytochrome c was initially slow, followed by an acceleration. The results on regulation support the hypothesis that the polypeptide chain of iso-2-cytochrome c is the repressor of the synthesis of the functionally important iso-1-cytochrome c.     

Influence de la température sur la consommation d'oxygène de micropterna testacea (Gmel.) (Trichoptera Limnophilidae)

Resume Comme suite aux mesures de consommation d'oxygène faites sur les larves de Polycentropus flavo maculatus Pict., Plectrocnemia conspersa (Curt.) et Limnophilus rhombicus (L.) (Colladdeau 1961), il est étudié dans ce travail, l'influence de la température sur la consommation d'oxygène de Micropterna testacea (Gmel.).La consommation d'oxygène de M. testacea croît avec la température. Cet accroissement est faible entre 3 et 7°C. Dés 10°C jusqu'à 20–25°C, cet accroissement est net et régulier. La variabilité des mesures augmente avec la température. Cette courbe métabolisme-température indique une grande sensibilité aux variations de temperature. Ceci oppose la larve de M. testacea aux larves précedem-ment étudiées qui présentaient une bonne adaptation aux températures situées entre 3 et 20–22°C. Cette différence dans l'allure de la courbe métabolisme-température ne serait pas dûe à des différence de température dans les milieux de vie respectifs des larves, puisqu'elles peuvent se trouver ensemble dans le même ruisseau. Elle serait due au fait que les larves de M. testacea, très rhéophiles dans la nature, deviennent très sensibles aux variations de température quand les expériences sont faites en milieu stagnant.

---

Summary As a sequence to the study of oxygen consumption in larvae of Polycentropus flavomaculatus Pict., Plectrocnemia conspersa (Curt.) and Limnophilus rhombicus (L.) (Collardeau 1961) the author investigates the influence of temperature on oxygen consumption by the larva of Micropterna testacea (Gmel.).The oxygen consumption of M. testacea increases with temperature, slowly between 3 and 7°C, more rapidly but still regularly from 10°C to 20–25°C. Variability also increases with temperature. Such a Metabolism-Temperature curve indicates great sensitiveness to temperature variations in M. testacea, as a contrast with the precedingly studied larvae, which could be considered as well adapted to temperature ranging from 3 to 20–22°C. Such differences in Metabolism-Temperature curves are unlikely to be due to different temperature occurring in the animals'habitat, as they may all be found together in the same brook. The very rheophilous M. testacea larva becoming sensitive to temperature changes when studied in stagnant water, might ratber account for the difference.

     

Amussiopecten baranensis (Almera & Bofill, 1897) =Amussiopecten destefanii (Ugolini, 1903), bivalve du Miocène de Catalogne: Remarques sur le genre Amussiopecten

The study of some recently sampled specimens of «Pecten galloprovincialis var. baranensisAlmera & Bofill, from the type-locality Bará (Tarragona), leads to rise this variety to a specific level. Amussiopecten baranensis (Almera & Bofill, 1897) is a senior synonym of Amussiopecten destefanii (Ugolini, 1903). The distinction between this species and Amusium cristatum (Bronn), which have been often confused, is more precisely defined. A. baranensis is polytypic, as proved by some morphotypes from other European localities (Gard and Landes in France, Sardinia). Its stratigraphic distribution is mainly Helvetian sensu lato or Middle Miocene.Signification and affinities of the genusAmussiopecten are also discussed. As a transitional form to Amusium, A. baranensis may contribute to clarify its taxinomic position, specially by means of microsculptural characteristics: a completed diagnosis is provisionally proposed.