Action de l'ecdystérone sur l'apolysis et l'ecdysis de divers crustacés isopodes

Ecdysterone acts differently according to the period of the moulting cycle when it is applied. In period C it induces apolysis, while at the beginning of apolysis it delays ecdysis. Experiments show that the exoskeleton cannot be rejected in the presence of ecdysterone. The possibility of stopping exuviation or ecdysis with ecdysterone seems to prove that this phenomenon is controlled by a particular factor called the factor of exuviation or the ecdysis factor. Ecdysterone would control only the release of this specific factor but would not prevent its action.     

Purification de l'alcool deshydrogénase de tomate par chromatographie d'affinité

Tomato alcohol dehydrogenase has been purified 99-fold by affinity chromatography on Blue Sepharose CL-6B with 37% yield. The enzyme so obtained is homogenous in polyacrylamide gel electrophoresis. By adding 20% glycerol to the extraction and purification buffers, an enzyme is obtained which is stable for several months at 4°. The molecular weight values determined by gel filtration (Sephadex G 200) and polyacrylamide gradient gel electrophoresis on one hand and by polyacrylamide gel electrophoresis in sodium dodecyl sulfate on the other, show that the enzyme exists in dimeric form.     

Caracterisation d'une ATP-ase membranaire en presence d'une phosphatase acide dans les lutoïdes du latex d'Hevea brasiliensis

Latex lutoids constitute a polydispersed vacuole with lysosomal character. Lutoids possess a membrane which retains ATP-ase and acid phosphatase activity. Acid phosphatase may be inhibited by ammonium molybdate or phosphate, making it possible to characterize an ATP-ase with an optimum pH of between 7·5 and 8·0. This ATP-ase is Mg²⁺ dependent, does not require K⁺ specifically but is affected by the ionic concentration of the medium.     

L'action exercée par l'appareil endocrine sur les phases tardives de l'ovogenèse chez Locusta migratoria

Most studies dealing with the endocrine control of oogenesis are focused on vitellogenesis, but the later events of oogenesis: vitelline membrane formation and choriogenesis have received less atention. In Locusta migratoria, the corpora allata evidently control vitellogenesis, but seem to have no bearing upon the formation of the vitelline membrane or the chorion. If the insects are deprived of their CA at the time when the oocyte length is around 3.5 to 4 mm, (normal length at egg laying: 6.5 mm) vitelline membrane formation and the chorion production are unaffected. In the same species, the electrocoagulation of the pars intercerebralis or excision of corpora cardiaca disturb oogenesis; vitelline membrane material is synthesized and secreted, but the primary granules fail to join each other and to transform into vitelline membrane and the production of chorionic material is disturbed.The rER of the follicle cell seems quite active but the substance elaborated accumulates in the Golgi saccules, and therefore the cytoplasm contains only very few secretory granules. The implantation of supernumerary pars intercerebralis and corpora cardiaca into immature females induces precocious deposition of the vitelline membrane which is complete in 5.0 mm oocytes (instead of 5.6 to 6.0 mm) and chorion formation is completed in 5.5 mm oocytes (instead of 6.0 to 6.3 mm). Ecdysone is secreted in the ovaries at the end of oogenesis. We tested the result of injecting ecdysone to immature females. It results in hastening oocyte growth during 24 hr, but this accelerated growth is followed by degeneration.     

Analyse biostratigraphique et paléontologique de l'Albien marin d'Estremadura (Portugal)

The marine Albain from Estremadura is splited up into four Orbitolinidae zones, adjusted to biostratigraphic scales from mesogean province: zone with Orbitolina (Mesorbitolina) minuta (lower to middle Albian); zone with Neorbitolinopsis conulus (base of upper Albian); zone with Orbitolina (Orbitolina) concava (top of upper Albian) and zone with Orbitolina (Orbitolina) duranddelgai (Vraconian). The vertical extension of the main fossils is replaced in the framework of these zones. The most interesting species for biostratigraphy, paleoecology or taxinomy are summarily described.     

Presence of immunoreactive β-endorphin in plasma of patients with Nelson's syndrome and Addison's disease

A sensitive radioimmunoassay for β-endorphin (β-EP) has been developed with an antiserum obtained from a guinea pig immunized with β-EP which was contained in crude porcine ACTH preparations (Organon). The minimal detectable quantity of β-EP was 1 pg. This antibody has the same affinity for β-EP and β-LPH on a molar basis, but human ACTH, α-MSH, β-MSH, α-EP, γ-EP, Met⁵-Enkephalin and Leu⁵-Enkephalin failed to displace ¹²⁵I-β-EP from its antibody. Utilizing this radioimmunoassay we have demonstrated the existence of β-EP in plasma from patients with Nelson's syndrome and Addison's disease.     

Sur le caractère probablement artificiel d'un C-benzyl flavonoïde obtenu à partir d'un hydrolysat de feuilles d'Hymenosporum flavum

Besides quercetin, kaempferol and isorhamnetin, at least three other flavonoids can be obtained from the leaves of Hymenosporum flavum after acid hydrolysis. One of these, a kaempferol derivative: p-hydroxyphenyl,(3,4′,5,7 -tetrahydroxy)-8-flavonyl, methylmethane or 8-α-methyl-C-(p-hydroxybenzyl)kaempferol has been identified by study of its spectral properties. It is probably an artifact formed during hydrochloric acid treatment of the leaves.     

Relation métabolique entre l'arginine et l'acide γ-aminobutyrique dans le fruit de Castanea sativa: étude préliminaire de l'arginase

Analysis of the free amino acid pool in the chestnut fruit (Castanea sativa) shows that it is high in γ-aminobutyric acid. A metabolic connection between arginine and γ-aminobutyric acid is evident. Three enzymatic activities are involved: L-arginine ureohydrolase, L-ornithine 2-oxo-acid aminotransferase and L-glutamate carboxylyase.     

Structure cristalline d'une deuxième forme de mélézitose monohydrate. Effet de l'environnement sur la géométrie d'un oligosaccharide

Melezitose [O-α-d-glucopyranosyl-(1→3)-β-d-fructofuranosyl α-d-glucopyranoside] monohydrate crystallizes in two polymorphic forms (I and II). The structure of form II, studied by X-ray crystallography, shows an orthorhombic cell having a 7.135 (4), b 15.362 (8), c 19.134 (8) Å, space group P2₁2₁2₁, and Z 4. The structure, solved by direct methods, was refined to a final value of R 0.045. The molecule of form II seems to be more constrained by its crystalline environment than that of form I. These constraints imply not only little variations in glycosidic bonds, but also a change of conformation for the furanose ring, and a perceptible deformation of the sucrose pyranose ring. This study gives an example of estimation of oligosaccharide molecular-flexibility.     

The origin of fibonacci phyllotaxis—an analysis of Adler's contact pressure model and Mitchison's expanding apex model

Adler's contact pressure model for Fibonacci phyllotaxis is examined theoretically. It is shown that the model, as it stands, does not account for Fibonacci phyllotaxis, since it requires, but does not provide, a mechanism for initiating new primordia with increasingly greater precision as phyllotaxis rises. Modifications are suggested which remedy this deficiency in the model; one of these modifications involves a combination of Adler's model with Mitchison's model.From a comparison of the ranges of divergence angles permitted by Adler's model against Fujita's measurements of divergence angles in plants with low phyllotaxis, it is shown that the modified contact pressure model, if based on the concept of mechanical pressures between primordia in contact, cannot account for the divergence angles found in low phyllotaxis systems. However it is shown that this deficiency can be overcome if the contact pressure effect is regarded as a chemical phenomenon, mediated by a growth inhibitor produced by the prirnordia and moving more readily in vertical directions than in other directions.Mitchison's model, which is based on the concepts of an expanding apex and primordium initiation by existing primordia, is shown to account for Fibonacci phyllotaxis only if phyllotaxis rises sufficiently slowly; to guarantee that an F_n + F_n+1 system can develop there must already be at least F_n+1 primordia present in an F_n?1 + F_n system, at least F_n primordia in an F_n?2 + F_n?1 system, and so on down to at least three primordia in a 1 + 2 system, making a total of at least F_n+3?5 primordia (where F_n = nth term of the Fibonacci series with F₁ = F₂ = 1). Adler's model, modified, requires only that F_{n + 1} primordia be present with divergence angles in the range 120–180° to guarantee that an F_n + F_{n + 1} system can develop.     

Scolécodontes,assemblage et appareil de vers annelidespolychetes errantes de l'aptien de la région d'Agadir,Maroc

From the Aptian scolecodonts inventory of the Agadir area one jaw apparatus and one joining of polychetes are reconstructed. One is the elementary species Schistomeringos expectatusSzaniawski & Gazdzicki, 1978, the oldest representative of the multielementary family Dorvilleidae Chamberlin 1919. The other is a representative of either the multielementary families Atraktoprionidae Kielan Jaworowska 1966 emend. Kozur, 1970 or Arabellidae Hartman 1944. This joining is considered as an hypothesis since all the necessary criteria, defined by H. Szaniawski & A. Gazdzicki 1978, are not all present.     

How well does Turing's theory of morphogenesis work?

In 1952 Turing published a paper which showed how under restricted conditions a class of chemical reactions could give biological patterns in diffusion-coupled cells. Although this theory has been much discussed, little has been learnt about the range and type of pattern it can generate. In order to do this and to see how stable the patterns are, we have examined the system in detail and written a computer program to simulate Turing's kinetics for two morphogens over various assemblies of cells. We find that on one-dimensional lines of cells, patterns can indeed be produced and that the chemical wavelengths follow all of Turing's predictions. The results show that stable repeating peaks of chemical concentration of periodicity 2–20 cells can be obtained in embryos in periods of time of less than an hour. We do find however that these patterns are not reliable: small variations in initial conditions give small but significant changes in the number and positions of observed peaks. Similar results are observed in two-dimensional assemblies of cells. On rectangles, random blotches are observed whose position cannot be reliably predicted. On cylinders whose circumference is less than the chemical wavelength, annular stripes are produced. For larger cylinders, blotches that lie very approximately on helices are generated; again sharp prediction of the detailed pattern is impossible.The significance of these results for the developing embryo is discussed. We conclude that Turing kinetics, at least in the simple cases that we have studied, are too unreliable to serve as the generating mechanism for features such as digits which are characterized by a consistent number of units. The theory is however more than adequate by these criteria to specify less well-defined developing patterns such as those of hair follicles or leaf organization. It is emphasized however that the Turing theory is quite unable to generate regulative systems, only mosaicpatterns can be produced.     

L'âge du complexe récifal des côtes de meuse entre verdun et commercy et la stratigraphie de l'oxfordien dans l'est du bassin de Paris

The question of the age of «Hauts de Meuse coral rag is studied again using new faunas of brachiopods and ammonites collected above, below and inside the coral rag. Ammonites fauna of the well known «Calcaires de Creuë is revised. Results obtained agree closely.The «Hauts de Meuse coral rag grew up during Middle Oxfordian time; and extend part of the Plicatilis zone (Antecedens Subzone) and the whole Transversarium Zone up to the basis of the Bifurcatus Zone, for the first time identified in Lorraine. So it span a short depositional time, about 1 MY, with a high deposition rate, the thickness of the coral rag being more than 100 meters, reaching 150 meters in Saint-Mihiel area. Towards SE, on the other side of the Marne Gap, the sudden change into basinal facies go with a reducing of thickness and deposition rate.Upper Oxfordian deposits show a relative uniformity of facies and thickness. At the top of Middle Oxfordian limestones, the age of the discontinuity and the Sequanian renewal of deposition is basal Bifurcatus Zone. Erosional renewal and terrigeneous deposits are a wide spread event by the beginning of Upper Oxfordian.In the paleontological part, species upon which are based new ages and interpretations are only figured, except the species new or with new paleontological data, which are described. Type specimen of Perisphinctes mosensisBayle, from the «Calcaires de Creuë, is described and photographically figured for the first time.     

Modalités d'installation et d'évolutiondes Harpocératinés (ammonitina A) au Domérien inférieur dans le sud-Ouest de l'Europe (France,Portugal)

In Mesogea, the Harpoceratinae were known asearly as the end of the Lower Carixian. They later reached the sub-boreal province through the Alps or the South of the Iberic Peninsula. The analysis of the populations met in four crosssections of the Lower Domerian (Causses, Mâconnais, Franche-Comté, Portugal) showed the settling down of the Protogrammoceras isseli group that set up and evoluated in a similar way in the different areas in spite of a certain originality.On the one hand, it gave the cladogenetic groupP. monestieri-nitescens by diminution of the ribing density, strengthening of the ribs and simplification of the suture.On the other hand, a slower evolution give, near the end of the Stokesi zone, P. normanianum in the Paris Basin and in Burgundy, and P. lusitanicum in Portugal. At the same time, a new invader, P. celebratum, arrived in the Causses (and in Portugal).