Corrélations de croissance entre le mycélium et les rhizomorphes chez le Sphaerostilbe repens

Correlation of Growth between Mycelium and Rhizomorphs in Sphaerostilbe repens In Sphaerostilbe repens Berkeley and Broome, cultured on a solid medium in Petri dishes, growth of mycelium and chizomorphs depends on the thickness of the culture medium underlying the thallus. On shallow layers of agar medium, aggregated units were fewer and rhizomorph growth reduced. Vegetative mycelium which starts growth earlier than rhizomorphs contributed to inhibit the development of these latter. On deep layers of substrate, rhizomorphs were numerous, elongated rapidly, and eventually inhibited undifferentiated mycelium. – There was no evidence for the involvement of any inhibitor substance diffusing into culture medium or located in the thallus. Development of aerial mycelium and rhizomorphs, could, on the contrary, be interpreted as nutritional competition between these two parts of the colony.     

Mise en evidence d'une reaction croisee entre les marqueurs allotypiques Aa1 et Aa2 du locus a chez le lapin

It is well known that, in rabbits, the allotypes of the b locus carried by the light chains of the IgG molecules cross-react. Nothing similar has been described for the allotypes of the a locus carried by the heavy chains of the IgG molecules. This paper describes a cross-reaction between the rabbit allotypic markers Aa1 and Aa2 of the a locus. This phenomenon became evident in successive I¹²⁵-labelled IgG precipitation experiments with a particular serum.     

Donnees chronologiques et morphologiques sur le mode de formation des corps jaunes,dans les conditions de la ponte provoquee chez la ratte

Résumé Les modalités morphologiques et chronologiques de la formation des corps jaunes ont été étudiées dans les conditions de la ponte provoquée chez la ratte.Des rattes Wistar offrant des cycles de 4 jours et préparées au début du cycle par une dose non lutéinisante d'oestradiol ont été soumises le 2ème jour de ce cycle à un stimulus copulatoire de 8 coïts.Ce stimulus suscite la formation de deux types de corps jaunes: les uns sont des corps jaunes postovulatoires édifiés aux dépens de follicules rompus; les autres sont des corps jaunes à ovule inclus formés aux dépens de follicules non encore aptes à se rompre mais déjà aptes à se lutéiniser.Ces corps jaunes se forment progressivement de la 11ème à la 24ème heure après le rapprochement sexuel. Un petit nombre d'entre eux sont déjà repérables dans les ovaires de rattes sacrifiées 11 heures après le coït. Leur nombre s'accroît au cours des 13 heures suivantes aux dépens de follicules prélutéiniques que l'on observe dans les ovaires des rattes sacrifiées 11 heures après le coït.

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Summary Morphological and chronological modalities of the formation of corpora lutea were studied in the conditions of evoked ovulation in the rat. 4-day cyclic female rats of the Wistar strain received at the beginning of the cycle a non luteinizing dose of oestradiol. They mated on the afternoon of the 2th day under visual control and mating was limited to 8 acts of coïtus. Two types of corpora lutea elicited by coïtus were observed i. e. postovulatory corpora lutea and corpora lutea with included ovocytes. Their formation proceed from about the 11th to the 24th hour after coïtus. A few number of these corpora lutea were already visible on the 11th hour post coïtum. Their number progressively increased during the following hours from preluteinic follicles which appeared in great number in the ovaries of animals sacrificed on the 11th hour after coïtus.

     

Relations entre le benthos,la derive,le rythme alimentaire et le taux de consommation de truites communes (S. trutta L.) en canal experimental

Relationships between benthos, drift, feeding rhythm and consumption rate of brown trout were investigated in an artificial stream in late spring. There are good correlations between insects activities and feeding rhythm of the trout. There are two feeding periods, the first one, more important, occurs at dusk and the second one in early morning. Daily ration is 6% of trout dry weight.     

Relations entre production et localisation de mycosporine et morphogenèses reproductrices chez le Pyrénomycète Gnomonia leptostyla

Relations between production and localisation of mycosporin and reproductive morphogenesis in the Pyrenomycete Gnomonia leptostyla.
The production of mycosporin (P310) has been analysed in Gnomonia leptostyla (FT.) Ces. et de Not. during mycelial growth and reproductive morphogenesis (macroconidiogenesis, microconidiogenesis and differentiation of perithecia). Conidiogenesis is induced in illuminated cultures while darkness promotes perithecial development. At 20°C, the cultures produce either macroconidia or perithecia with abortive sporophyte. Microconidia differentiation and perithecia maturation require low temperature (10°C). Mycosporin is, at all times, present in the thallus. However, the concentration of mycosporin in highest in the conidiogenous thallus, intermediate in the perithecial thallus. and lowest in the vegetative mycelium. In the conidiogenous thallus, macroconidia and microconidia are both sites of mycosporin accumulation. On the contrary, in the perithecial thallus, mycosporin levels are not higher in perithecia than in mycelia, even during their maturation period. The quantitative variations of mycosporin during the thallus development and its accumulation inside conidia suggest translocation from sites of synthesis towards reproductive cells.     

Testicule et sperme dans le Syndrome de Klinefelter chez l'adulte

Klinefelter's syndrome is characterised by azoospermia, gynecomastia and hypogonadotropic hypogonadism. The testes are reduced in volume. Microscopically, seminiferous tubules show a reduced diameter and a thickening of peritubular sheath. The seminiferous epithelium contains Sertoli cells with a clear typical nucleus and a heterogeneous nucleolus. Usually there are no germ cells. When present they degenerate at the spermatocyte stage. Very few achieve a complete maturation until the spermatozoon form. The interstitial gland appears relatively hypertrophied, due to the decrease in volume in the other components of the testis. Sometimes Leydig cells display an adenomatous morphology. Therefore the steroidogenic function is impaired. Azoospermia is a major event in Klinefelter's syndrome but sometimes restricted to severe oligozoospermia. In that cases, fertility may be somewhat preserved, and the caryotype usually reveals a mosaicism, 47,XY/47,XXY with a better prognosis than in pure syndrome.     

Analyse comparative de la séquence sexuelle chez les Ipopodes Oniscoidea de la série ligienne en relation avec le développement de la volvation chez les Armadillidiidae et les Armadillidae

A comparative study of the sexual sequence is carried out in four Oniscoidea of the ligiid series Porcellio laevis, Metoponorthus sexfasciatus (Porcellionidae), Armadillidium vulgare (Armadillidiidae) and Armadillo officinalis (Armadillidae). The differences between the four species chiefly appear in the precopulatory manoeuvres. The integration of coiling or uncoiling reactions in the sexual sequence of coiling forms is studied in two genera: Armadillidium and Armadillo. Results of the behavioral study provide information about the evolution of the group.     

Influence de l'intensité et de la longueur d'onde de la lumière sur le rendement des radicaux libres dans les semences de tomate et de carotte

Influence of light intensity and wavelength on the yield of free radicals in seeds of tomato and carrot.
Seeds of tomato ( Lycopersicum esculentum L. cv. Gribovsky-1180) and carrot ( Daucus carota L. cv. Santanet) were irradiated by continuous light of different wavelengths (white, blue, green, red, far-red and He-Ne laser) and different power density. Free radical output was measured using Electron Spin Resonance spectra (ESR). The dependence of the content of free radicals (FR) on the light power density was established. The yield of FR in the seeds irradiated with monochromatic light of the same power density was inversely proportional to the wavelength. The ESR spectra showed maximum absolute number of FR for white light. Successive irradiations gave cumulative effects on the output of free radicals in both directions: increase by the action of white light and decrease by the action of red and far-red light. The contact of irradiated seeds with steam decreased the amount of FR.