Existence of an ejaculatory-like reaction in ewes ovariectomized and treated with androgens in adulthood

The complete behavioral repertoire of male sexual activity can be observed during daily androgen treatment (testosterone propionate, 15 mg/day) of normal ewes ovariectomized as adults. This includes the ejaculatory pattern (deep thrust accompanied by a rapid backwards movement of the head) which is followed by a dramatic decrease in the frequency of sexual interactions, similar to the male's postejaculatory reduction of activity. However, the sexual performances of the genetic females remain lower than those of normal males in ejaculation latency, postejaculation latency, and mount/ejaculation ratio.     

Isolation of the RAD18 gene of Saccharomyces cerevisiae and construction of rad18 deletion mutants

Summary The RAD18 gene of Saccharomyces cerevisiae is involved in mutagenic DNA repair. We describe its isolation from a yeast library introduced into the centromeric YCp50 vector, a low copy number plasmid. The insert was sublconed into YCp50 and into the multicopy YRp7 plasmid. RAD18 is not toxic when present in multiple copies but the UV survival response indicates an heterogeneity in the cell population, a fraction of it being more sensitive. A DNA segment, close to RAD18, is toxic on the multicopy plasmid and may correspond to the tRAN sup61 known to be tightly linked to RAD18. Chromosomal deletions of RAD18 were constructed. The gene is not essential and the deleted strains have the properties of single site mutants. Thus, RAD18 appears to be essentially involved in DNA repair metabolism.     

Detection by DGGE of a new polymorphism closely linked to the adenomatous polyposis coli region

Summary The EF5.44 locus is in close proximity to the chromosome 5 region to which the genetic defect responsible for familial adenomatous polyposis has been mapped. We have devised two oligonucleotides that promote the specific polymerase chain reaction (PCR) amplificiation of a 365-bp sequence in this region. Analysis by denaturing gradient gel electrophoresis of the resulting fragment has unravelled individual differences that could be identified as a single base pair change in aMnlI restriction site. This PCR assayable polymorphism increases the informativeness at this locus, and should be useful in the presymptomatic diagnosis of familial adenomatous polyposis.     

Cloning of genes that encode a new heat-labile enterotoxin of Escherichia coli.

The genes for a new enterotoxin were cloned from Escherichia coli SA53. The new toxin was heat labile and activated adenylate cyclase but was not neutralized by antisera against cholera toxin or E. coli heat-labile enterotoxin. Subcloning and minicell experiments indicated that the toxin is composed of two polypeptide subunits that are encoded by two genes. The two toxin subunits exhibited mobilities on polyacrylamide gels that are similar to those of cholera toxin and E. coli heat-labile enterotoxin subunits. A 0.8-kilobase DNA probe for the new enterotoxin failed to hybridize with the cloned structural genes for E. coli heat-labile enterotoxin.     

Introduction dans le Sud-Est de la france d'un parasite:Pauesia cedrobii [Hym.: Aphidiidae] du puceron:Cedrobium laportei [Hom.: Lachnidae] du cèdre de l'atlas:Cedrus atlantica

Résumé Le parasitePauesia cedrobii Stary et Leclant, spécifique du puceron du CèdreCedrobium laportei Remaudière, a été récolté dans le Moyen-Atlas, (Maroc) puis introduit dans un peuplement de cèdre (Cedrus atlantica Manetti) du sud-est de la France au printemps 1981. La méthode utilisée a consisté en une introduction directe des parasites, préalablement isolés sur le lieu de récolte (momies) puis mis à éclore en chambre climatisée de fa?on à éliminer les hyperparasites. Après accouplement, 225 adultes ont été introduits dans des manchons installés sur des rameaux abritant des colonies deC. laportei. L'évolution des populations de l'h?te et du parasite a été suivie au niveau des points de lacher d'une part, et dans la parcelle d'autre part. L'installation définitive du parasite dans la parcelle s'est produite, 1 an après le lacher, grace à un automne et à un hiver particulièrement doux, qui ont favorisé la multiplication de l'h?te. Le parasite est définitivement implanté: il est encore présent 4 années après le lacher. Entre temps, il a été étendu à d'autres forêts de cèdre du sud-est de la France. Huit espèces d'hyperparasites autochtones se sont portés surP. cedrobii, mais ceci ne remet pas en cause la réussite de l'introduction de l'aphidiide. Avec la collaboration technique deE. Robert, A. Chalon, J. Chizky.     

Endocrine aging in C57 BL mice--II. Dynamics of estrogen receptors in the hypothalamic-pituitary axis

Specific cytosolic and nuclear binding sites for estrogens were measured in the hypothalamic-pituitary axis (HPA) of young (4-8 months) and old (16-18 months) C57 BL mice in order to determine any age-related alteration in hormone-receptor interaction. Our results indicated no age differences in the affinity (KD = 0.89 +/- 0.03 (SEM) vs 1.09 +/- 0.2 X 10(-9) M), the specificity, the sedimentation profile (6 s) or in the number (98.9 +/- 4.9 vs 84.4 +/- 2.3 fmol/mg protein) of unoccupied estrogen binding sites in the cytosols. Estradiol administration to young mice induced a complete translocation of cytosolic estrogen receptors to the nucleus, and two types of nuclear binding sites were observed: Type I were specific for estrogens with high affinity (KD = 0.51 +/- 0.06 X 10(-9) M) and low binding capacity (115.1 +/- 22.7 fmol/mg DNA) and sedimented in the 4.0 s area, while Type II binding sites showed a much higher capacity and lower affinity for R2858. HPA nuclear suspensions of aged untreated mice showed undetectable (less than 50 fmol/mg DNA) levels of nuclear estrogen receptors and E2 pre-treatment resulted in a significant increase in both types of binding sites. While no significant changes in the physicochemical characteristics of these nuclear receptors were observed, when compared to young animals, aging was manifested by a translocation defect in the HPA of C57 BL mice. These results suggest aging changes in the endocrine regulating centers of the brain with defective activation of estrogen receptors.     

A UV-supersensitive mutant in the yeast Schizosaccharomyces pombe

Summary A high UV-sensitive mutant was obtained from a UV-sensitive strain of the yeast Schizosaccharomyces pombe after a mutagenic treatment. By genetic analysis, it was possible to distinguish two independent loci. The double mutant is supersensitive, that is more UV-sensitive than either of the two single mutants. This suggests that the mutations involved interfere with two repair pathways that are, at least partially, independent of each other.Some properties of the two single mutants were studied. These mutants differ notably in their response to caffeine, to liquid-holding, to exposure to visible light after UV irradiation, and in their UV-sensitive during the logarithmic growth phase.Comparison of the properties of the wild-type strain and of the different UV sensitive mutants leads to the conclusion that one repair pathway is used preferentially in the wild-type strain.Abbreviations DRF dose reduction factor - LH liquid holding