Transport de l'auxine-14C en provenance de jeunes gousses de Vicia faba L.

Summary After the injection of [¹⁴C]indole acetic acid (IAA) into very young pods of broad-bean (Vicia faba L.) the movement of the ¹⁴C in the peduncle and stem was followed by autoradiography. In samples with only one young pod the basipetal transport was always clearly dominant. Most of the radioactivity was found in the bundles, particularly in the outer region of the bundle and also in the inner region (protoxylem parenchyma). The progression of the tracer was relatively complex. The rate of movement of the radioactive «front» could be as much as 2 cm·h^-1 but most of the ¹⁴C moved towards the base at rates clearly less than that of the «front». Chromatograms with several solvent systems showed that IAA was the main or the only mobile radioactive substance. During transport, a part of IAA was converted into indole-3-aldehyde (IAld) and indole-3-acetyl-aspartic acid (IAAsp). IAAsp and possibly also IAld, which were found mainly near the donor pod, seemed immobile. This work is part of a study on the interchange of phytohormones between fruit and plant.

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Abréviations AIA acide indolyl-acétique - AIAsp acide indolyl-acetyl-aspartique - IAld indolyl-aldéhyde     

Produccion de esferulas endosporuladas por inoculacion de hongos artroconidiosporados aislados del suelo

With several fungi isolated from samples of soils obtained in the province of San Luis and in the province of Mendoza (Argentina), we employed a simple technique for the inoculation in the mice's foot in order to provoke the formation of endosporulated spherules.As a conclusion, it could be proved that all these strains classificated as Gimnoascaceae, genus Malbranchea sp. and Auxarthron zuffianum, produce what appear to be endosporulating spherules. The viability of the endospores was not demonstrated nor was disseminating infection produced.     

Etude de la fertilité des eaux marines au moyen de tests biologiques effectués avec des cultures d'algues. II. Limitation nutritionnelle et viabilité de l'inoculum

Ten cultures of phytoplankters, including four strains of Skeletonema costatum from different origins, were used to improve some aspects of the bioassay technology. Special attention was paid to the preliminary nutrient limitation of the inocula. When the cells are maintained in nutrient starvation, their carbon, nitrogen, carbohydrates, proteins and above all chlorophyll a contents decrease. The minimum appears after a range of 2–7 days, according to species. The survival of these limited cells and their capacity to give rise to active growing cultures when sub-cultured are different with species, but efficiency in the inocula they provide usually can occur only until the minimum content in cellular components appears. Starved cells and enriched cultures of Chaetoceros lauderi and Skeletonema costatum were used to inoculate several samples of sea water, in order to test the effect of the starvation on the experimental results. It appears that the starved cells increase the sensitivity of the method, but they are more susceptible to substances limiting their growth. In the opinion of the authors the best way would be to use both starved and enriched cells as inocula, but, when this is impossible, cautiously starved cells should be used with unpolluted sea waters.     

Cestodes d'oiseaux de Côte-d'Ivoire. II. Parasites de Coraciiformes et Piciformes

Résumé Les cestodes récoltés en Côte d'Ivoire chez deux ordres d'oiseaux, les Coraciiformes et les Piciformes, sont présentés. Un nouveau genre, Thaumasiolepis (Hymenolepididae, Hymenolepidinae), est créé et discuté. Il comprend des cestodes récoltés chez différentes espèces de Capitonidae et caractérisés par des crochets rostraux spiniformes tout à fait originaux. L'espèce T. microarmata est créée pour ce matériel. D'autre part deux nouveaux Raillietina de Picidae, R. (S.) campetherae et R. (P.) yapoensis sont décrits. R. (S.) campetherae est la première espèce de ce sous genre trouvée chez les Piciformes. Biuterina meropina macrancistrota est trouvé chez Merops albicollis. Ce taxon est élevé au rang d'espèce et devient par conséquent B. macrancistrota Fuhrmann, 1908. Skrjabinoporus merops (Woodland, 1928) Spassky & Borgarenko, 1960 est retrouvé. Cette espèce peu commune est redécrite et sa position parmi les Metadilepididae confirmée. Enfin, Raillietina cf (P.) bargetzii Mahon, 1954 est signalé chez Gymnobucco calvus.

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Cestodes collected in the two bird orders, the Coraciiformes and the Piciformes, in the Ivory Coast are presented. The new genus Thaumasiolepis (Hymenolepididae, Hymenolepidinae) is created and discussed. It includes cestodes collected in two species of the Capitonidae. Its main characteristic is the presence of very unusual spiniform hooks. The species T. microarmata is created for this material. We also describe two new species of Raillietina parasitising the Picidae, R. (P.) yapoensis and R. (S.) campetherae, the latter being the first species of this subgenus recorded from the Piciformes. In addition, Biuterina meropina macrancistrota has been found in Merops albicollis. We recognize a full specific status for this taxon which becomes B. macrancistrota Fuhrmann, 1908. Skrjabinoporus merops (Woodland, 1928) Spassky & Borgarenko, 1960 has been rediscovered. This rare species is redescribed and its position among the Metadilepididae is confirmed. Finally, Raillietina cf (P.) bargetzii Mahon, 1954 is recorded from Gymnobucco calvus.

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Ce travail fait partie de la thèse du premier auteur.     

Plants of the ‘Libellus de Medicinalibus Indorum Herbis’ from Mexico, 1552. Zephyranthes fosteri (Amaryllidaceae) Alkaloids

The Libellus de Medicinalibus Indorum Herbis (Booklet of Indian Medicinal Plants) is the first book of medicinal plants written in the American continent. It was first published in 1939 as ‘An Aztec Herbal’. One of the depicted plants is Huetzcanixochitl (laughing flower) interpreted as Zephyranthes fosteri (Amaryllidaceae). No chemical or pharmacological studies are reported for this species; so, we decide to investigate it. The GC/MS of the bulbs and aerial parts extracts indicated that they contain Amaryllidaceae alkaloids, among them: lycorine, 3-O-acetylpowelline, and norlycoramine. An unknown major alkaloid was isolated and identified by ¹H, ¹³C-NMR and MS, as 3′-demethoxy-6-epimesembranol ( 1 ). The methanolic extract, the alkaloid fraction, and compound 1 inhibited acetylcholinesterase in vitro. Mesembrine alkaloids are found in Sceletium species (Aizoaceae). Several are known as serotonin recapture inhibitors and have been proposed as potential antidepressant drugs. The presence of 1 suggests that Z. fosteri was probably used in pre-Columbian times in Mexico as a ‘stimulant and euphoriant’, alike Sceletium tortuosum by several ethnic groups in South Africa.     

Ecophysiologie de quelques Desmidiées: II. Perturbations expérimentales de la nitrate — respiration

Résumé L'étude porte sur deux Desmidiées dont l'activité nitrate-respiratoire a déjà fait l'objet d'un travail précédent.On observe que les algues carencées en azote perdent leur activité nitrate-réductrice, tandis qu'elles utilisent des quantités de nitrite beaucoup plus grandes que dans les conditions expérimentales habituelles.En présence d'acide ascorbique, on note une modification fréquente, mais variable, des activités nitrate- et nitrite-réductrices. Les algues protègent cet acide et les nitrites contre une oxydo-réduction réciproque.Les algues étudiées semblent pouvoir utiliser, suivant les circonstances, différents systèmes énergétiques.

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Summary Previous experiments (C. van der Ben, 1970) have shown that several species of Desmids are able to reduce nitrates to nitrites in vivo. This reducing property depends greatly on various environmental factors such as pH, temperature, light and nitrate concentration.The present paper analyses some conditions of this nitrate-reducing capacity, i.e. nitrate-respiration. The factors investigated are nitrogen-privation and action of ascorbic acid. It has been found that Staurastrum cultures deprived of nitrogen after exponential growth phase become unable to reduce nitrates but their nitrite-reduction is enhanced. The present observations show that algal suspensions protect ascorbic acid and nitrites against mutual destruction.In the presence of ascorbic acid, the nitrate- and nitrite-reducing activity of the algae is frequently and variably modified. Staurastrum and Cosmarium seem to have the ability to switch to various energetic sources according to environmental conditions.

     

Identification of genes required for de novo DNA methylation in Arabidopsis

De novo DNA methylation in Arabidopsis thaliana is catalyzed by the methyltransferase DRM2, a homolog of the mammalian de novo methyltransferase DNMT3. DRM2 is targeted to DNA by small interfering RNAs (siRNAs) in a process known as RNA-directed DNA Methylation (RdDM). While several components of the RdDM pathway are known, a functional understanding of the underlying mechanism is far from complete. We employed both forward and reverse genetic approaches to identify factors involved in de novo methylation. We utilized the FWA transgene, which is methylated and silenced when transformed into wild-type plants, but unmethylated and expressed when transformed into de novo methylation mutants. Expression of FWA is marked by a late flowering phenotype, which is easily scored in mutant versus wild-type plants. By reverse genetics we discovered the requirement for known RdDM effectors AGO6 and NRPE5a for efficient de novo methylation. A forward genetic approach uncovered alleles of several components of the RdDM pathway, including alleles of clsy1, ktf1, and nrpd/e2, which have not been previously shown to be required for the initial establishment of DNA methylation. Mutations were mapped and genes cloned by both traditional and whole genome sequencing approaches. The methodologies and the mutant alleles discovered will be instrumental in further studies of de novo DNA methylation.     

Effect of light and media upon growth and melanin formation in aureobasidium pullulans (de By.)Arn. (=pullularia pullulans)

Summary Polysaccharides like dextrine and starch are shown to be the best carbon sources for the growth ofAureobasidium pullulans although growth is good upon a variety of other carbon sources. Light increases growth markedly when polysaccharides are the carbon source but not when other sugars are used. Variation in cell morphology is described in response to sugars and light. Extracellular granules, whose properties resemble those of melanin, are produced when dextrine is the carbon source in a defined medium containing asparagine as the source of nitrogen. The dark pigment was extracted from the walls of thick-walled brown cells ofA. pullulans and characterized as a melanin on the basis of several tests, including solubility and absorption spectrum.A. pullulans was grown on several defined and undefined media and the response of the fungus to light is shown to be determined by the medium, and the temperature at which the cultures are grown.     

Régulation de la synthèse du DNA dans la glande séricigène de Bombyx mori: II. Etude de l''activité DNA-polymérasique présente dans la fraction soluble brute

In the silkglands of Bombyx mori larvae, DNA synthesis suddenly stops in the middle of the fifth larval instar, when cellular growth is over and cell activity is turned on to massive silk synthesis. Of much interest is to determine what factors are implied in the quantitative and temporal control of DNA synthesis in this tissue.Previous work on thymidine metabolism in the intact organ lead us to look for several enzymatic activities in the soluble fraction of the cells during this period.The results presented here concern the kinases of the thymidylic pathway. As measured in vitro from crude cellular extracts, thymidine-kinase is present at a lower level than thymidylate-kinase but both activities vary in connection with the pattern of in situ DNA synthesis, reaching their highest levels on the fourth day of the instar and decreasing as DNA synthesis definitively stops in the glands.     

Caracterisation de la structure d'un processus de croissance

Resume L'analyse d'une cinétique de croissance y(t) est conduite à partir du modèle logistique généralisé de Richards-Nelder. On distingue 2 types de processus dits mono- et multi-logistique.Dans le cas mono-logistique, le phénomène est correctement décrit par une seule fonction logistique. La cinétique de croissance est alors caractérisée par lea propriétés de chacune des phases G ₁ à G ₄ , délimitées par les points singuliers _max, V _max et _min (Buis, 1991, 1993). On appelle structure de croissance (structure temporelle on diachronique) la contribution relative de ces différentes phases à l'expression de la croissance totale (durée, quantité de croissance, en valeurs relatives par phase, indépendamment de y _max). Cette distribution temporelle de l'activité de croissance est une représentation discrétisée de la trajectoire y ₀ y _max.On appelle processus multi-logistique toute cinétique de croissance correspondant à une somme de 2 ou plusieurs logistiques généralisées. II existe alors un plus grand nombre de points singuliers (extremums locaux de V et ) et donc un plus grand nombre de phases G _i que dans le cas monologistique. La structure de croissance définit avec précision la cinetique du phénomène, ainsi que l'importance relative des différentes composantes logistiques au cours du temps.Une application en est donnée avec le grandissement des cellules pleuridiophores de l'Algue Antithamnion plumula (Rhodophyceae, Ceramiales). L'allongement de ces cellules est toujours de type bi-logistique. Les caractéristiques de la structure de croissance permettent une discrimination nette du sporophyte et des gametophytes mâle et femelle. Tandis que la composante 1 (la plus importante en début de grandissement) est pen différente, la composante 2 varie fortement selon la ploïdie du thalle. En revanche, il y a pen de différences entre les deux gamétophytes.Cette notion de structure de croissance est ainsi susceptible d'apporter des résultats originaux. Audelà de cet example, cette approche est proposée comme une méthode de caractérisation simple mais précise de toute cinétique de croissance basée sur lea variations temporelles de l'activité de croissance [couple (V, )].

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Characterization of the structure of a growth processApplication à la croissance des cellules pleuridiophores de l'Algue Antithamnion plumula Application to the growth of the pleuridiophoral cells of the alga Antithamnion plumula

The analysis of a growth kinetics y(t) is carried out using the generalized logistic model of Richards — Nelder. Two types of processes, termed mono- and multi-logistic, can be distinguished.In a mono-logistic process, the phenomenon is adequately described by only one logistic function. The growth kinetics is then characterized by the properties of each of phases G ₁ to G ₄, with boundaries defined by the singular points _max, V _max and _min (Buis, 1991, 1993). The growth structure (temporal or diachronic structure) is defined by the relative contribution of the various phases to the expression of the total growth (duration, growth amount, in relative values per phase, independently of y _max). This temporal distribution of the growth activity is a discretized representation of the trajectory y ₀ y _max.A multi-logistic process corresponds to any growth kinetics which is the sum of 2 or several generalized logistics. The number of singular points (local extrema of V and ), and therefore the number of phases G, are then higher than in the mono-logistic case. The growth structure defines precisely the kinetics of the phenomenon as well as the relative importance of the various logistic components in the course of time.The application presented concerns the growth of the pleuridiophoral cells of the alga Antithanurion plumula (Rhodophyceae, Ceramiales). Cells elongation is of the bi-logistic type. The elongation growth structure characteristics afford a clear discrimination between the sporophyte and the male and female gametophytes. Whereas component 1 (which is the more important at the beginning of growth) hardly changes, component 2 varies dramatically with the thallus ploïdy. In contrast, there are few differences between the two gametophytes.The growth structure concept is thus liable to lead to original results. Beyond the example selected, the approach considered is put forward as a simple but precise characterization method for any growth kinetics based on temporal variations of the growth activity [(V, ) couple].

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Ce travail a été réalisé dans le cadre du programme de recherche du Groupe Physiologie, Phylogénie et Morphogénèse des Algues.     

Activité,in vivo, d''inhibiteurs de la biosynthèse de l''ecdysone chezLocusta migratoria

Summary Among about 50 compounds synthesized to inhibit enzymes involved in the biosynthesis pathway of ecdysone we selected seven molecules which showed a strong effect on ecdysone production byLocusta migratoria prothoracic glands incubatedin vitro. These molecules mostly possess a specific activity on ecdysone biosynthesis which is irreversible. The compounds were administered in one or several injections of aqueous or oily solutions at different times in the course of the two last larval instars. Three inhibitors led in a 10% ratio to a prolongation (sometimes more than 3 times the standard length) of the instar, pointing out a decrease in the ecdysone biosynthesis. Two other inhibitors induced some morphogenetic modifications in the adults, as size reduction or wing alterations, and metamorphosis difficulties. Thein vivo low activity compared with the strong onein vitro could be due to difficulties for the compounds to reach the prothoracic glands without degradation. The variation of inhibitory activity which appearsin vivo between the seven compounds studied is not linked either with the chemical structures of the molecules (which are very near one another) or with theirin vitro activity.

     

Une phytotoxine de Xanthomonas campestris pv. vasculorum

A phytotoxin from Xanthomonas campestris pv. vasculorum I. Purification and partial characterization Xanthomonas campestris pv. vasculorum, the causal agent of sugarcane disease produces, when maintained in pure culture, a host selective phytotoxin. The molecule obtained at a high purity level is a strongly acid polyalcohol.     

Activite ovarienne de Tetrastichus atriclavus (Chalcidien, Eulophide). Effets de l'accouplement et de la presence de l'hote

Résumé Tetrastichus atriclavus, Eulophide de zone tropicale, s'attaque aux chrysalides de divers Lépidoptères. Il est élevé au laboratoire sur un hôte de remplacement: Galleria mellonella (Pyralidae), à 26°5 et à la photopériode 18 h (L) / 6 h (D).Dans ces conditions, l'accouplement a peu d'influence sur l'activité de ponte: la différence entre la fécondité des femelles vierges et celle des femelles accouplées n'est pas significative. De plus, les femelles vierges ont un fonctionnement ovarien comparable à celui des femelles accouplées.La fécondité est maximale en présence continue de l'hôte. L'absence d'hôte entraîne des rétentions, sans résorption. Lorsque l'hôte est introduit plusieurs jours après l'émergence du parasite, la capacité de ponte de ce dernier diminue. La diminution est d'autant plus grande que le temps de privation est plus long. Un grand nombre d'ufs est pondu immédiatement après l'introduction de l'hôte. Si le temps de privation est inférieur ou égal à 10 jours, on assiste, après la ponte massive du premier jour, à une reprise de l'activité du germarium.

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Summary Tetrastichus atriclavus, an Eulophid which is found in tropical regions, parasitises pupae of several Lepidoptera. It is reared in the laboratory on Galleria mellonella pupae, at 26.5° and with the photoperiod 18 h (L)/6 h (D).Mating has little influence on oviposition: there is no significant difference between the fecundity of virgin and mated females. Fecundity is highest when the host is always present. When the host is provided several days after the emergence of the parasite, the number of eggs laid is lower, the decrease being higher as the absence of host is longer. Many eggs are laid just after the host is provided. If the absence of host is 10 days or less, the germarium becomes active again after the heavy oviposition on the first day.

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Nous dédions ce travail à la mémoire du Professeur J. R. Le Berre, avec notre hommage reconnaissant et ému.     

La Cryoconservation de la laitance de la carpe, Cyprinus carpio

Cryo-preservation of carp, Cyprinus carpio, sperm Deep-freezing trials of carp sperm were carried out by varying several factors such as the basic saline solution, the cryoprotectors added (glycerol, propanediol, ethylene glycol and DMSO), the media (Menezo-INRA B², egg yolk, urea) and the deep-freezing and dilution rates. The success of deepfreezing was judged by the percentage of motile spermatozoa, intensity of motility, fertilizing ability and morphological integrity of the spermatozoa studied under the scanning electron microscope. DMSO was the best cryoprotector and the mineral composition of the dilution medium the least important factor, but there was noticeable improvement after organic compounds were added. The following mixture has been proposed: NaCl 100 mM + KC1100 mM, Tris 20 mM, pH 8: 37%, Menezo medium B² INRA: 15%, urea 5%, DMSO: 10%, fresh sperm: 33%. Optimal deep-freezing rate was: 5°C/min from 2 to-7°C and 25°C/min from-7 to-70°C. In these conditions, about 70 to 80% of the spermatozoa were motile after thawing compared to fresh control sperm, but fertilizing ability was not more than 30 to 40% of that with fresh sperm. The percentage of spermatozoa considered intact was 66% after thawing as against 83% for fresh control sperm. The motility and fertilizing ability of deep-frozen sperm were significantly improved when the dilution rate at insemination was reduced from ¹/₁₀₀ to 1/2.     

Au sujet de la caractérisation des produits a base deBacillus thuringiensis Berliner par rapport au titrage biologique de la toxine soluble thermostable

Summary Industrial products based onB. thuringiensis have been found to contain several toxins, differing in their ranges of activity and occuring in varying quantities. The presence of the ?thermostable toxin activeper os? is in particular unnoticed in the assay of the active material in the products, in spite of the fact that many studies of the application of products based onB. thuringiensis, concern insects whose sensitivity is limited to or dominated by the thermostable toxin. Biological assay can be envisaged for the estimation of the thermostable toxin in industrial products, while awaiting the development of other assay methods In this manner, the products will be charasterized as to their active material, for the benefit of the understanding of experimental or practical results. It is suggested that it would be more rational, on the international scale, to use as reference a standard preparation based on an autoclaved filtrate ofB. thuringiensis var.thuringiensis, than to use a standard biological assay method which involves an test insect. The precision of assay for ?thermostable toxin activeper os? can be greater or smaller, according to the insects for which the product is recommanded or on which it is tested.

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Ce mémoire a été présenté à l' ?International Symposium on the identification and assay of viruses and Bacillus thuringiensisused for insect control?, Londres, 13 juillet 1964.

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I.N.R.A., Station de Recherches de Lutte biologique et de Biocœnotique, La minière.     

Phytochrome et germination des semences de Rumex

The Rumex alpinus L. achenes show a special type of positive photosensitivity: several red light irradiations are necessary to induce optimal germination. The achenes deprived of their pericarp lose their photosensitivity and germinate readily in the dark. By spectrophotometry in vivo, the presence of the Pr form of phytochrome is revealed in these seeds. Short periods at extreme temperatures (30°C or 5°C) induce a good proportion of achenes to germinate. The gibberellins are inefficient on achene germination contrary to benzyladenine which exhibits some activity. A slight improvement of GA₄ effects has been detected on scarified fruits.     

Ofiuroideos de los archipielagos de Chiloe y los Chonos

In marine faunistical prospections made in the Chiloé and Chonos inlets between 1970 and 1973, five ophiuroid species were collected: Gorgonocephalus chilensis (Philippi, 1858),Astrotoma agassizii Lyman, 1875; Ophiomyxa vivipara Studer, 1876; Ophiophragmus chilensis (Müller and Troschel, 1843) and Ophiactis asperula (Philippi, 1858). Morphometric data about the specimens as well as the geographical distribution of the species are given. With the purpose of contributing to the zoogeographical knowledge of this area of the Chilean littoral, an analysis of the geographical distribution of all species mentioned for this region is done.     

Redescription of Antetintinnidium mucicola (Claparède and Lachmann, 1858) nov. gen., nov. comb. (Alveolata,Ciliophora, Tintinnina)

Tintinnid ciliates have traditionally been described and classified exclusively based on their lorica features. Although information on the cell characters is urgently needed for a natural classification, more molecular than cytological data has been accumulated over recent years. Apparently, the tintinnids developed in the marine environment and entered freshwater several times independently. Typical freshwater tintinnids belong to the genera Tintinnidium and Membranicola. The species are comparatively well‐known regarding their morphology and characterised by two unusual de novo originating ciliary rows, the ventral organelles. In contrast, the cell features in the marine/brackish Tintinnidium species, specifically their somatic ciliary patterns, are insufficiently known or not known at all. Therefore, the morphology of a common marine/brackish representative, Tintinnidium mucicola, is redescribed based on live observation and protargol‐stained material. Furthermore, biogeographical and autecological data of the species are compiled from literature and own records. The phylogenetic relationships of T. mucicola are inferred and the diversity of the family Tintinnidiidae is assessed from 18S rDNA sequences. The study shows that T. mucicola is not only molecularly distinct, but also characterised by many plesiomorphic features, for instance, it does not possess a verifiable homologue to the ventral organelles. Hence, a new genus, Antetintinnidium nov. gen., is established for T. mucicola. The new insights into the diversity of Tintinnidiidae shed light on the early evolution of tintinnids and might provide clues on their adaptions to freshwater.