Activité Cellulolytique des Ciliés Entodiniomorphes

RESUME. Dans nos travaux antérieurs, nous avons observé dans les cultures in vitro que la disparition de la cellulose (languettes de papier filtre) est 2 fois plus grande lorsque les 2 micropopulations, Entodinium et bactéries, sont présentes que lorsque les bactéries sont seules ou en présence de cellules mortes de ciliés. Les filtrats des broyats cellulaires des ciliés entodiniomorphes de la panse des ruminants et du caecum des équidés possèdent une activité cellulolytique indépendante des bactéries endocellulaires. Il s'agit essentiellement d'une polyglucosidase (Cx) qui dégrade les dérivés de la cellulose native. On observe également une légère activité cellulolytique C₁ sur la cellulose native.
SYNOPSIS. We have observed previously that twice as much cellulose disappears from cultures containing both Entodinium and bacteria than from those which contain bacteria alone or with dead ciliates. Filtrates of cell-free homogenates of the entodiniomorphid ciliates from sheep rumen and horse cecum have a hydrolytic effect upon cellulose, hydrolytic activity being independent of the intracellular bacteria. The predominant enzyme involved in the reaction is a polyglucosidase (Cx) which acts upon derivatives of native cellulose. Low level activity of enzyme C₁, which attacks native cellulose, also is found in the filtrate.     

Étude des activités photochimiques des étiochloroplastes isolés de plantules verdies en lumière intermittente

Photochemical Activities of Etiochloroplasts Isolated from Plants Greened under Intermittent Light. I. Absorption of Oxygen. Oxygen exchange by isolated etiochloroplasts from wheat leaves (Triticum sativum Lam. cv. Florence Aurore) has been studied with an oxygen electrode. The etiochloroplasts lack an oxygen evolving mechanism and show a light induced oxygen uptake with two components. One component, sensitive to 3-(4-chlorophenyl)-1,1-dimethylurea, results from electron flow through an active photosystem II and is suppressed by photosystem II electron donors. The other component is inhibited by quinones suggesting that it might represent some mechanism to trap and dissipate excitation energy from chlorophyll in competition with that produced by the presence of artificial traps. The results are discussed in order to explain the apparent lack of coupling between photosystem II, through which some electron flow is operating, and the active photosystem I present in these plastids.     

« Statut de Berger » des communautés atlasiques, néolithisées du Maghreb oriental, dès 7000 BP

Neolithization through karstic rocky territories from Eastern Maghreb is supported by a special form of pastoralism. Between 7000-5000 BP, a prominent sheep and goat animal husbandry represents a shepherd’ permanent objective, while domestic cattle seems to play a saving role. Aurès reaches allowed us to study a global shepherd living, initiated by small groups, labelled as Neolithic of Capsian Tradition, stricto sensu (NCT). A new approach focuses here on non local archaeological finds from the Capéletti cave, a residential key-site located on the slopes of the Khanguet Si Mohamed Tahar amphitheatre (1540m), gives the lead to explore a winter lowland transhumance behaviour, which was a yearly extension of a summer upland behaviour. Through synchronized data, selected among exotic cultural documents, such as polished stone axes and adzes; marine and ivory-ornaments; and lowland botanic remains from marshes, such as elements of a steppic and salted vegetation, trapped inside sheep fleece, new evidences emerged which were linked, then, with new data based on flocks evaluation as alive animals. This study gives precision on:

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the shepherd’s long term objective;

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the initial and natural animal husbandry which moved, through an empirical management, on an increasing and controlled sheep, goat and cattle breeding;

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the non local cultural goods broad-spectrum, coveted by the shepherds;

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the flock meat/animal goods, coveted by peddling nomadic people;

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the exchange act and its conventions;

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how and when vanished epipaleolithic traditions of this NCT facies, through shepherds’ deliberate and progressive exchanges;

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and how and when, outside farming process, might have appeared, on lowlands and hilly areas, a typical open countryside landscape, strictly linked with this ongoing pastoralism.

This first local Status of the Shepherd which was the main objective of this neolithization may have settled and spread out through Maghreb territories, an Atlasic Pastoral Society.     

L'appareil de Golgi des Ciliés. Ultrastructure, particulièrement chez Paramecium

Electronmicroscopic study of Coleps, Colpidium, Stylonychia, and especially of Paramecium confirmed the presence of the Golgi complex in these fresh-water ciliates. The complex consisted of numerous dictyosomes scattered throughout the cytoplasm. Each dictyosome included a few flat, partly reticulated saccules lying parallel to a cistern of rough endoplasmic reticulum which was free of ribosomes on the side exposed to the dictyosome. A unique layer of vesicles, characterized by constant size and a thick wall, separated the endoplasmic reticulum from the dictyosomes. The vesicles could be regarded as transition vesicles. Coated vesicles were seen in continuity with some of the flattened saccules. The possible role of the Golgi complex in the physiology of ciliates is discussed.     

Biosynthèse des acides gras polyinsaturés des glycérolipides de la feuille d'olivier

The patterns of incorporation of [l-¹⁴C]-acetate into the glycerolipid fatty acids of leaves of olive plants ( Olea europea L. cv. Chétoui) suggested a specific pathway for a-linolenic acid biosynthesis. The results confirmed the involvement of phosphati-dylcholine in galactolipid metabolism, and seemed to exclude the role of that mole-cule as a substrate for desaturation of oleate to linoleate. The two oleate desaturation steps seemed to occur rapidly on the diacylgalactosylglycerol molecule for biosynthesis of galactolipid linolenate. In addition, the results indicated a slow sequen-tial desaturation of oleate to linolenate via linoleate in the phospholipid molecules (phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol).     

Réponses des adultes de Lasiomma melania,ravageur des cônes de Larix decidua, à des pièges colorés de différents types

La réponse visuelle des adultes de Lasiomma melania Ackl. (Diptera, Anthomyiidae) à des carrés englués de diverses couleurs ou combinaisons de couleurs a été étudiée durant 5 années consécutives dans plusieurs mélèzins (Larix decidua) des Hautes-Alpes. Une préférence pour le jaune et le jaune à bandes pourpres a été mise en évidence chez ce ravageur dont la femelle pond sur les cônes de mélèze. L'attractivité de chaque type de piège est fonction à la fois du sexe et du stade de maturation sexuelle des individus. La couleur jaune attire en majorité des insectes émergents immatures. Elle semble représenter, selon le plan dans lequel elle est située, un signal nutritionnel de type fleur (plan horizontal) ou un signal de reconnaissance du feuillage de mélèze (plan vertical). Les individus mûrs sexuellement, recherchant les arbres produisant des cônes, sont en revanche capturés essentiellement sur les pièges verticaux jaunes à bandes pourpres. Ceux-ci miment, en l'amplifiant, le contraste de réflectance existant entre le feuillage des mélèzes et les cônes. Ce contraste paraît correspondre à un signal permettant la reconnaisance des arbres possédant des cônes. La ponte est cependant limitée à un stade particulier de développment de ces derniers alors que le contraste est à peu près stable dans le temps. D'autres signaux émis par les cônes, vraisemblablement d'ordre olfactif, doivent guider le vol d'approche et l'atterrissage des femelles.     

Les kystes de dinoflagellés des Argiles Ostréennes du Bassin de Paris, France

Palynological studies realized from a borehole drilled on the site of ANDRA (Agence Nationale pour la gestion des Déchets RAdioactifs; Aube Centre near Soulaines, Paris Basin, France) show a sedimentary discontinuity between, on one hand, the Argiles à Plicatules (lower Aptian in age) and Argiles Ostréennes (Lower Barremian/Upper Barremian in age) and, on the other hand, between these same Argiles Ostréennes and the Calcaire à Spatangues (Lower Hauterivian). These conclusions argue against the chronostratigraphical subdivision recently proposed on the basis of sequence stratigraphical and sedimentological interpretations.     

Identification des impacts de projectiles sur le squelette des grands ongulés

In the context of the collective research program “functional technology of solutrean points”, conducted from 1987 to 2000, more than 300 impacts were experimentally produced on ungulate carcasses (goat, cow, horse). Based on the classification of these types of impacts proposed by P. Morel in 1991, we can estimate that only the inclusions of point fragments in the bones remain diagnostic in most archaeological contexts. The other types, such as scrapings or splittings, can be confused with tool traces, carnivore tooth marks or postdepositional alterations. P. Morel has published the results for small herbivores, and we present our results here for large herbivores. More than 200 stigmata were observed on the carcasses of an adult cow and horse following experimental shots with solutrean projectiles (shouldered points, laurel leaf points and willow leaf points) and a few reindeer antler points. These traces are concentrated around the vital parts of the animals. The most common types are marginal scrapings and splittings, but implantations are more numerous than on small ungulate skeletons. This numerically significant body of data is derived from carefully controlled experiments. Indispensable for the interpretation of the stigmata observed on bones found in Paleolithic sites, such experiments contribute to our knowledge of the conditions prey exploitation and allow us to address questions concerning the fossilization of these traces and their apparent frequency.     

Recherches sur les enzymes catalysant la biosynthèse des acides phénoliques chez Quercus pedunculata. III. Formation séquentielle, à partir de la phénylalanine, des acides cinnamique, p-coumarique et caféique, par des organites cellulaires isolés

The reactions leading to cinnamic acids from phenylalanine as only substrate were investigated in organelles from Quercus pedunculata Ehrh. roots. –“F 10 000′” fraction, including mitochondria and micro-bodies, catalyses the first reaction, i.e., cinnamate formation by deamination of phenylalanine. – Microsomal fraction catalyses all the steps from phenylalanine to caffeic acid via cinnamate and p-coumarate. These results suggest that microsomes are the intracellular site of the cinnamic units synthesis. The enzymes involved in these reactions, associated in the same cellular compartment, does not form a multienzyme system. The formation of caffeic acid by isolated microsomes is demonstrated for the first time; the reaction may be realised by an enzyme different from phenolase. – The free phenolic acids are the metabolically active forms.     

Système Sétifère des Maxillipèdes des Gonodactyloidea (Crustacea, Stomatopoda)

Analysis of the setal system was conducted on the maxillipeds of Gonodactyloidea, which includes the smashers, a functional group of stomatopods. Generally, the homogeneity of the setal system is demonstrated in stomatopods. However, examination of maxillipeds of Gonodactyloidea reveals that some setal types are systematic characters at levels of families or species. The smashers group has a very homogeneous setal system in three families: Gonodactylidae, Odontodactylidae and Protosquillidae. The setal analysis of maxillipeds confirms the functional role of these appendages. Like other morphological characters, the setal system of stomatopods has co-evolved with behavioral patterns in both groups: spearers and smashers.