Recherches sur les microorganismes de type mycoplasme dans les cicadelles vectrices et dans les vegetaux atteints de jaunisses

Résumé La phyllodie du trèfle, le Stolbur C et le Stolbur SM ont été étudiés chez la cicadelle Euscelis plebejus, les plantes Trifolium repens, Cuscuta subinclusa, Datura stramonium et Solanum lycopersicum en microscopie électronique, sur coupes ultrafines et après purification des agents infectieux.Dans les différents hôtes infectés, on distingue des éléments de grande taille, de forme ovoïde, amiboïde ou allongée, des corpuscules très contrastés, isolés ou en chaînettes, de fins filaments et des élements dégénérescents.Chez les cicadelles, la dégénérescence de ces microorganismes est probablement due à une réaction immunologique qui expliquerait la perte régulière du pouvoir infectieux de ces vecteurs.Chez les plantes, cette dégénérescence peut en partie rendre compte des phénomènes de rétablissements définitifs ou temporaires que manifestent parfois certains végétaux atteints de ces maladies.

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Summary The microorganisms causing the diseases Clover phyllody, Stolbur C and Stolbur SM were studied in the leafhopper Euscelis plebejus, and in the plants Trifolium repens, Cuscuta subinclusa, Datura stramonium and Solanum lycopersicum, by electron microscope examination of ultrathin sections and purified suspensions.In infected host plants and insects the following components were distinguished: large, ovoid, amoeboid or elongated bodies, well-contrasted isolated or chained microbodies, minute filaments, and degenerate elements. Some of these bodies resemble mycoplasma.In the leafhoppers it is possible that the degeneration of these mycoplasma-like microorganisms is due to an immunological reaction, which may explain why aged vectors do not transmit the diseases.In plants, the degeneration of the microorganisms was also observed. This loss may partly account for the occasional complete, or temporary, recovery of diseased plants.

     

L'influence de l'age sur les échanges de nourriture entre les ouvrières d'abeillesApis mellifica

Résumé En utilisant de la nourriture marquée avec un radio-isotope, il a été possible de constater, chez des groupes d'ouvrières de même âge et provenant de la même ruche, que les échanges étaient nuls à l'âge d'un jour et passaient par un maximum vers l'âge de 4 jours.

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Summary The exchange of food among worker bees of same age coming from the same bee-hive was studied by means of marking the food with radioisotope. The present study shows that there is no exchange of food among 1 day old worker bees but it starts taking place when the worker bees are 2 day old reaching a maximum when the worker bees are circa 4 day old.

     

Etudes sur les Iguanidae de Madagascar

Résumé Les précisions apportées à la carte de répartition de Chalarodon madagascariensis, nous ont permis de déterminer dans l'étude climatologique les facteurs limitant l'externsion de cette espèce. Les deux principaux sont la pluviométrie et l'insolation. Les Chalarodons habitent la région de Madagascar, de plus forte insolation et plus faible pluviométrie, et de climat sub-aride à semi-aride et chaud (température maximale parmi les plus élevées de l'île). Ils vivent en plein soleil. Ce sont des Lézards typiquement xérophiles et héliophiles.Ils sont adaptés à la vie en terrain sablonneux où ils se déplacent acec rapidité et creusent leurs terriers. La répartition de ces terrains explique les variations de densité à l'intérieur de l'aire.La végétation la plus caractéristique est le «bush» xérophile, assez clairsemé pour ménager au sol l'ensoleillement nécessaire.Ces Lézards ne présentent pas une hibernation vraie mais un fort ralentissement d'activité pendant l'hiver austral (saison sèche et fraîche).Cette étude des facteurs de l'environnement nous permet de décrire quelques aspects de leur biologie en relation avec leur écologie (cycles d'activité, nutrition, etc.).

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Studies on the Iguanidae of MadagascarII. Remarks on the ecology of Chalarodon madagascariensis Peters, 1854

Summary The detailed comments that we made on the repartition map of Chalarodon madagascariensis enable us to define, in the climatological study, the factors limiting the extension of this species. These number two, namely rainfall and sunning. The Chalarodons live in that region of Malagasy where solar heat is strongest and rainfall lowest, and where hot climatological conditions range from subarid to semiarid (the maximum temperature is one of the highest in the island). They live in full sunlight. They are typically xerophilous and heliophilous lizards.They are adapted to life in sandy grounds, over which they move about most swiftly and out of which they dig their holes. The manner these sandy grounds are distributed accounts for the varying density within the area.The most characteristic vegetation is xerophilous bush, sparse enough to afford sufficient sunlight to the ground.These lizards do not undergo real hibernation, but only a marked slackening in their activity during winter in the southern hemisphere (dry and cool season).Lastly this study of the factors of environment allows us to describe some aspects of their biology in relation to their ecology (cycles of activity, nutrition, etc.).

     

Remarques sur les propositions de nomenclature phytosociologique de Meijer Drees

Sans résumé     

Action de la quinoline sur les mitoses de segmentation des eufs d'urodèles: le blocage de la centrosphère

Quinoline in saturated solution (0,46 M) progressively destroys spindle and astral fibers, beginning in the juxtacentromeric region; it blocks the centrosphere material around the centriole. Chromosomes are immobilized in equatorial position far off the blocked centrospheres and may undergo telophasic transformation into karyomeres. Diastema may be inactivated before mitosis. Centrospheres are first deprived of some fibers, then granular and more or less dissociated, last completely smooth and segregated into cortex and medulla. Breaks and recombinations of chromosomes may appear after a long while, when a brief action is interrupted. With less concentrated solutions monopolar mitoses and monopolar telophases (rosettes) are observed (1/8 saturated solution), then shortened bipolar mitoses (1/16 saturated). Qualitative differences between quinoline and colchicine actions are evident.     

Brisures de symetrie hierarchisant les niveaux d'organisation

1. The sequence of the organisation levels is regarded as originating from a sequence of symmetry breakings. Each breaking generates a more improbable structure. In addition to the Euclidian symmetries, homogeneity, isotropy, translation, rotation, helix displacement, neutrality and even indiscernibility can be broken. Here are considered the initial (§ 2) and the subatomic breaking molecular morphogenesis (§ 3, 4) and other higher breakings.2.1 HOMOGENEITY BREAKING OF THE VACUUM SPACE. We studied this as a new model of wave-corpuscle relation. Every noticeable point breaks the space homogeneity. Directed by a momentum this breaking operates as a fissure.2. Postulate of the corpuscle. The quantum mechanical corpuscle is the end of a fissure, the momentum of which characterises direction and velocity.2.2. Postulate of the wave. The associate wave comes from the end of the fissure and works to split the medium.2.3. Corollary to the trajectory. The fissure prefers continuity and a straight line. Nevertheless the fissure can stop at a point and then start from an other point. This discontinuity and any momentum possible discontinuity are limited only by uncertainty relationships; frequency of discontinuity is limited by the first one. Vacuum has no memory of the fissures. 2.4.Corollary to the localisation. The fissure diminishes the medium constraints and allows the medium to vibrate in a domain surrounding the end of the fissure.2.5. Physical analogies.

- Photo-elastic studies of the fissuration of solids (Corten & Park, 1963) show a little sphere and a wavelike perturbation at the end of the fissure.

- A fragile and resonating object can be broken by a sound wave. This crack emits a sound wave. Here we consider one associated wave, emitted and absorbed.

- Broken panes picture an emission of rays.

li]2.6. Consequences of the fissure model (without modifying the laws of quantum mechanics).

1. The corpuscle generates a fractal trajectory. From literature (Abott & Wise, 1981; Nelson, 1966) or from the present model we can calculate a fractal dimension, namely 2. But this numerical value corresponds to the simplest assumptions. Inhomogeneity or rapid changes in time could increase this value. The actual fractal dimension is a physical property which was neglected until now. It can govern the probability of collision between corpuscles, hence the probability of nuclear fusion between corpuscles, like deuton, the enhancement of which at low energies was recently discovered (Fleischman & Pons 1989).
2. The difficulties linked with the extrapolation from macroscopic structure vanish. No wave is indefinitely extended. Corpuscle can disappear and reappear again (e.g. it can pass through a nodal surface). The indiscernibility is included in the model.

li]3. ATOM HYBRIDIZATION. The calculated value of the entropy (Chantelot & Laforgue, 1966) demonstrates that the hybridization is a physical phenomenon. It corresponds to the breaking of the spherical symmetry into a polyhedral symmetry. Hybridized orbitals can be a priori determined by equiprobability of the different angular momenta for the atom (which cannot be measured into a molecule). The independently determined eigenfunction enables one to find the same symmetry. li]3.1. Image of the molecule on the basis of a constituent atom. The “natural orbitals” of the molecular wave function of such a basis describe pertinently the atom symmetry breaking and the supplementary deformation by the molecular surrounding. li]3.2. The criterion of the so-called “maximum ponderated overlapping” leads to the “image orbitals”. Hence we obtain a generalization of the well known criterion of Pauling. li]3.3. Physical sense of the “image orbitals”. They describe the molecule from the point of view of the atom. They are adapted to the bonding of the atom with its molecular surrounding. li]4. THE CHIRAL BREAKNG. Referring to previous publications (Laforgue, 1983, 1988, 1989a, b, c, d, 1990) asymmetrical molecules oscillate or break depending on the height of inversion and destruction barriers. Fig. 1 pictures the domains of stability. Fig. 2 pictures the so-called “Path of Easiest Destruction and Inversion”. li]4.1. Equations of the chiral breaking. The more general case is the endothermic one (Fig. 3). Some equations are proposed. The so-called destruction time {Eq A} and inversion time {Eq B} determine by {Eq Z} process the final symmetry {Eq C} or final chirality {Eq D}. A more accurate treatment is the application of the Bohr-Heisenberg principle. If the inversion barrier is higher than the destructive one, the classical solution is confined to the right or to the left; hence the quantum behaviour is a random tunnelling and not a periodical oscillation (at low quantum numbers the amount of inversion is negligible). The results are experimentally verified because no evolution in chiral structure other than random inversion was ever observed. li]4.2. Chiral molecule is a pseudo-stationary state. Two enantiomers are distinct molecules. They do not have the symmetry of the Hamiltonian because they are not a solution of the Schrödinger's amplitude equation. li]4.3. Chiral constraint. The complete error potential is formulated. It follows an electronic oscillation and intra-molecular forces on the nuclei. In an oscillating molecule these forces affect the oscillation. The forces become permanent by chiral breaking, which explains asymmetrical properties. li]4.4. Chiral medium. A molecule submitted to asymmetrical forces has asymmetrical properties. Some of these effects have not yet been formulated but should be postulated (e.g. induced electronic circular dichroïsm). Quantum measurement theory shows that the effective inversion time increases when chiral interactions become more frequent. li]4.5. Biological role of chirality. Racemic life cannot work, hence there is optical symmetry breaking of the biosphere. It demands an initial preference and global autocatalysis, which can take the form of molecular recognition followed by defense mechanisms. The set of chiral molecules can be characterised as an intermediate level between matter and life. li]5. BREAKING OF THE CHIRAL LEVEL AND OF THE HIGHER ONES.

- The chain of identical chiral monomers can be submitted to an helix displacement breaking (i.e. non identical monomers) leading to a memory organisation level.

- If the electronic fluctuation through chemical bounding is broken, two systems of electrons become mutually discernable. That occurs on the organisation level of the super molecule.

- Following breakings generate spacial forms and acting mechanisms, as well known.

li]6. CONCLUSION. The reviewed breakings can be interpreted in terms of living requirements. There common cause is symmetry fragility. Matter and life derive from the vacuum space by successive spontaneous symmetry breakings. Finally, the question of an upper limit of organisation arises.