Indépendance des formes spectrales de chlorophylle a et des holochromes chlorophylliens

Independence of special forms of chlorophyll a and chlorophyll holochromesZea mays L. seedlings were cultivated for 10 days with submission to 4 s illumination periods interspersed with dark periods varying in length from 30 min to 6 h depending on the lot analyzed. The results show that, for the case in which the dark periods were shorter than 1 h, the relative proportions of different spectroscopic chlorophyll forms (maxima at 662, 670, 677.5, and 684 nm) were constant. For longer durations of darkness between illuminations, the relative proportion of the form Ca₆₇₀ increases, while that of Ca₆₈₄ diminishes with the length of darkness; to a lesser extent, the relative proportion of Ca₆₆₂ increases and a form Ca₆₉₂ disappears. A scheme is proposed to explain the evolution of the relative proportions of the different spectral forms.The different chlorophyll holochromes present in the chloroplasts were also analysed. If the dark period was longer than 1 h, chlorophyll was associated with peptide chains of molecular weights 21 000 and 29 000. If the dark period was shorter than 1 h chlorophyll was associated with four peptide chains of molecular weights 21 000, 25 000, 29 000 and 70 000.The results taken together demonstrate that a given spectral chlorophyll a form cannot be associated with a definite chlorophyll holochrome.     

Étude préliminaire des genres Cycadopteris Zigno, 1853 et Lomatopteris Schimper, 1869

The study of leaf-impressions, with preserved cuticles, collected in the Callovian of Bourgogne (France), and belonging to the genus LomatopterisSchimper, 1869 emend. Saporta, 1873, has permitted to confirm and justify the synonymy of the genera CycadopterisZigno, 1853 and LomatopterisSchimper proposed by Hirmer (1924). The cuticular studies have been carried on with a conventional optical microscope after an usual maceration and also with the use of the scanning electron microscope. Comparisons are established with cuticles proceeding from the Lias of Italy and refered to the genus CycadopterisZigno.     

Biogéographied'un groupe d'Échinides cénozoiques (Echinolampas et ses sous-genres Conolampas et Hypsoclypus)

Echinolampas is a subtropical genus living in rather shallow water; one may regards it as a climatic marker. The theory of continental drift affords a rather good explanation for its distribution in space during Cenozoic era. It appears in Old Wolrd during Paleocene and it occurs in Central America during Middle Eocene; that implies it had to cross the already broad Atlantic Ocean; but at that time this ocean is not as broad at it is now. Migration along the shelf area which rimmed North Atlantic might have been impossible, owing to disruption of land connection between Europe and North America. Probably the migration occured in low latitudes and pelagic larvae were transported by one of the two equatorial currents. Diversity of the genus has much decreased during Late Eocene. The cause may be chiefly due to climatic deterioration, resulting from marine communication between North Atlantic and Arctic Ocean. Echinolampas occurs for the first time in Australia during Oligocene. One may suggest the possibility of a link between this late evidence and the quite remote position till then of Australian continent. During Miocene, the relative decrease in Echinolampas diversity in the Mediterranean Basin occurs as a result of the welding between Asia and Africa.     

Précisions morphologiques,structurales et systématiques sur Reptomulticava parviporosa CANU et LECOINTRE (Bryozoa,cyclostomata)

This miocene organism was described as an Alga (Lithophyllym vinassaiPATRINI, 1932 = Neosolenopora patriniiMASTRORILLI, 1955) and as a Bryozoan (Reptomulticava parviporosaCANU et LECOINTRE, 1934). This paper shows several salient features of Cyclostomatous Bryozoans (morphology, microstructure, zoarial brood chamber). The arguments for the classing of this organism among Algae are simultaneously refuted (pseudo-differentiation of the thallus, conceptacles).     

Étude des variations du nombre et de la répartition des muscles longitudinaux chez Phoronis psammophila Cori

In 21 samples, staggered over 18 months, 1725 composite muscle formulae have been established for Phoronis psammophila Cori. The study of variations of the number and distribution of longitudinal muscle bundles demonstrates the increase of the muscle number (3 or 4) with the age of the animals. This increase is displayed with difficulty because of the interactions of many phenomena, especially reproduction and so statistical tests have not indicated significance. The general and especially mean formulae of different samples do not indicate the increase of the number of muscle bundles with time, as proposed by Emig.     

Distribution et activités des alcaloïdes défensifs des Coccinellidae

From a survey of 30 species and varieties of ladybugs the presence of alkaloids appears to be correlated with the existence of aposematic colour and not with being carnivorous or phytophagous. The alkaloids described until now all belong to the Coccinellini and are closely related, but other types of bases have been detected in some genera. The observed distributions are in agreement with the modern taxonomy of the family.Ladybug alkaloids constitute an effective defence against ants, Myrmica rubra, and quails, Coturnix coturnix, but all the beetles containing alkaloids do not possess the same degree of protection. Individual quail react differently towards moderately protected species.The bioassay used for the first isolation of coccinelin is described. The repulsive activities of aqueous solutions of coccinellin and convergin towards ants have been compared.     

13C NMR des alcaloïdes des Strychnos: Les dérivés de l'harmane et de l'usambarensine

¹³C NMR spectra of some tertiary and quaternary indole alkaloids are recorded and the signals assigned. Graphic interpretation of off-resonance spectra and substituent shielding effects together with the effect of N_b-methylation are utilized in the spectral interpretation.     

Contribution a la connaissancce des rhapydionininae (foraminifères, alveolinidae) crétacés

The formerly unknown microspheric form of Raadshoovenia salentina (Papetti and Tedeschi) and the new genus Cyclopseudedomia (type-species Cyclopseudedomia smouti n.g., n.sp.) are described from limestones of Campanian-Maastrichtian age from Gavrovo-Tripolitza zone in Greece. The new genus is distinguished from others of the sub-family RhapydionininaeKeijzer emend. Hamaoui and Fourcade by its almost entirely evolute test made of chambers tending to a cyclical stage (rapidly reached in the microspheric form).     

Mode d'action et propriétés des facteurs inducteurs issus du mésenchyme gastrique et des mésenchymes hétérologues

Résumé Des expériences d'associations d'épithélium gastrique de foetus de Lapin et de mésenchyme homologue ou hétérologue, partielles ou par membrane filtrante interposée, mettent en évidence l'existence de deux types de facteurs inducteurs.Le premier facteur induit la morphogenèse de l'épithélium. Il est thermostable et hautement diffusible.Le deuxième facteur, organospécifique, est plus ou moins favorable à la différenciation de l'épithélium gastrique suivant la nature du mésenchyme. Faiblement diffusible et thermolabile, il est élaboré dans la phase cytoplasmique des cellules mésenchymateuses.

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Action and properties of inductive factors proceeding from gastric and heterologous mesenchymes

Summary Experimental associations of gastric epithelium of the Rabbit foetus with homologous or heterologous mesenchyme, separated by membrane filter or partially associated, permit us to prove the existence of two types of inductors.The first factor induces the epithelial morphogenesis. It is thermostable and highly diffusible.The second factor, organospecific, is more or less favorable to the differentiation of the gastric epithelium according to the nature of the mesenchyme. Lightly diffusible and thermolabile, it is elaborated in the cytoplasmic phase of the mesenchymal cells.

     

Résumés des communications orales et affichées

XVIème Congres de la Societe d’Andrologie de Langue Francaise Issy-Les-Moulineaux 9-11 Décembre 1999

Résumés des communications orales et affichées     

La sculpture et l'infrastructure du sporoderme de Ginkgo biloba comparées à celles des enveloppes polliniques des cyccadales

The Ginkgo biloba sporoderm, when examined with transmission and scanning electron microscopes, shows a sculpture and a texture which are very different from those observed in cycads.The ornamental units are “rugules” which are evenly disperesed over the pollen grain surface except on the germinal zones which is decorated with “verrucoïde” components mixed with a few ridges. (2) The exine is composed of a tripartite sexine, the middle zone of which is full of irregular pits, and of a thick and strongly lamellated nexine.     

Côntrole neuroendocrine des protéines sanguines vitellogenes d'Anacridium aegyptium sain et parasite

The changing patterns of haemolymph proteins were followed in male and female adults of normal and parasitized Anacridium aegyptium during diapause (autumn, winter) or during activity (spring) of their endocrine system without or with electrostimulations of the pars intercerebralis (PI).The haemolymph protein concentration is high in winter and decreases in spring. It is comparatively depleted in locusts infected by the fly Metacemyia calloti. However, the depletion is significant only in ‘castrated’ females.Fifteen protein fractions were resolved by polyacrylamide disk gel electrophoresis in haemolymph of normal and infected locusts during diapause and activity. Some fractions decrease in quantity during activity in males, normal females, and parasitized females with complete ovarian development. One fraction disappears in females with mature eggs and seems correlated with formation of the eggshell. Eight others protein fractions exhibit electrophoretic mobility identical to the 7 protein fractions of homogenates of eggs. There is little doubt that these haemolymph protein fractions are involved in yolk synthesis and are thus ‘vitellogenic’. One of these ‘vitellogenic’ fractions (band 6) is larger in yolk than in blood.Five protein fractions were demonstrated by electrophoresis of homogenates of parasites. Their electrophoretic mobilities are similar to those of 5 of the 8 haemolymph ‘vitellogenic’ fractions of the host. There is little doubt that these 5 haemolymph protein fractions (one of them is the band 6) are involved in the nutritional requirements of the parasite.Electrostimulation of the PI, during diapause and activity, increase the haemolymph protein concentration and chiefly the protein concentration of the blood band 6. Thus, the median neurosecretory cells of the brain (M-NSC) regulate protein synthesis and chiefly the synthesis of ‘vitellogenic’ proteins.In parasitized females, the increase of the haemolymph protein concentration after electrostimulations of the PI is associated with an enhancement of ovarian development. The depletion of the haemolymph protein concentration in ‘castrated’ females is thus involved in the inability of the oöcytes to sequester available proteins from the haemolymph. The haemolymph protein deficiency may be attributed to (1) an impairment of protein synthesis, attendant upon the hypoactivity of the M-NSC, and (2) the nutritional requirements of the parasite.     

Détection des tumeurs T1 et T2 des voies aérodigestives supérieures : comparaison des performances diagnostiques en IRM et en TEP/TDM-FDG

ObjectiveExtracranial head and neck tumors classified T1 and T2, because of their small size, are more difficult to diagnose by imaging than the tumors of higher stage. The aim of this study is to evaluate and compare FDG-PET/CT and MRI accuracy for detection of small extracranial head and neck tumors.Materials and methodsA retrospective study was led on 21 patients having a histopathologically proven tumors involving the upper aerodigestive tract, classified T1 or T2 according to TNM staging, which received pre-therapeutic MRI and FDG-PET/CT. Tumoral detection ability was estimated on MRI and FDG-PET/CT by a qualitative scale. Sensitivities of the two methods of imaging were compared between then. The SUVmax and the percentage of enhancement were measured for each tumor and analysed according to T staging.ResultsAmong the 21 tumors, 17 were detected by FDG-PET/CT against 12 by MRI. None of the 4 unidentified lesions by FDG-PET/CT was visible on MRI. FDG-PET/CT correctly identified 5 of the 9 MRI false-negative results. The sensitivity was 80.9 % for FDG-PET/CT and 57.1 % for MRI, on the verge of the statistically significant difference (P = 0.06). There was no significant correlation of the SUVmax to the T staging.ConclusionFDG-PET/TDM could be useful for the identification of primary extracranial head and neck tumors, even small-sized, classified T1 or T2, with a sensitivity higher than MRI.     

Etagement des algues et des invertébrés sessiles dans l'Archipel de Glénan

The Glénan Archipelago was investigated, from the surface to a depth of 60 m, byScuba diving. Four distinct communities (“peuplements”) have been determined that fit into the system of zonation defined by the Genoa Symposium (1957). The results are compared with observations made in the English Channel (Cabioch 1968) and in the Atlantic Ocean (Glemarec 1971). Since illumination depends upon the angle of the rocky face, photophilic species exhibit a maximum range when the rock surfaces are horizontal. The sublittoral zone is dominated by laminarians. They form two distinct communities with the animal and vegetal species they overshadow. The upper community is characterized byLaminaria digitata (Linné)Lamouroux (horizontal rocky face from 0 to 6 m; vertical rocky face from +0.5 to ?3 m). The lower cummunity, characterized byL. hyperborea (Gunner)Foslie has a greater vertical extension (horizontal: ?6 m to ?26 m; vertical: ?3 to ?30 m). The circalittoral zone is colonized by several animal species growing in a ramified manner: the upper community is characterized by Axinellidae (?30 m), the lower byDendrophyllia cornigera (Lamarck) (?55 to ?60 m). Upright algae disappear somewhere between ?40 and ?47 m.     

Ostéologie et position systématiquedu genre Thrissops Agassiz, 1833 (sensu stricto) (Jurassique supérieur de l'Europe occidentale) au sein des Téléostéens primitifs

The osteological study of the genus ThrissopsAgassiz, 1833 (sensu stricto) from the Upper Jurassic of Germany and France allows to define the systematic position of that fossil fish within the primitive Teleosts. The general shape of the skull, the jaws, the ethmoidal area, the circumorbital bones, the fronto-parieto-supra occipital area, the parasphenoid and the opercular bones are all characters which prove that Thrissops belongs to the family Ichthyodectidae (order Ichthyodectiformes, super-order Osteoglossomorpha). However Thrissops is more primitive than the other Ichthyodectidae which are all of Cretaceous age. It possesses indeed two parietals bearing pit-lines, a premaxillary and a maxillary normally developed, a palatine and a metapterygoid without any contact, a denticulated entopterygoid, three free epurals and six uroneurals, while, in the Cretaceous Ichthyodectidae, the parietals are fused in one bone without any pit-line, the premaxillary and the maxillary are hypertrophic, the palatine touchs the metapterygoid, the entopterygoid is toothless, the epural disappear or fuse with the terminal neural arches to form supplementary neural spines, and the uroneural are only five.