Microgeographic and Temporal Genetic Differentiation in Natural Populations of DROSOPHILA SUBOBSCURA

Evidence of microgeographic and temporal genetic differentiation in natural populations of Drosophila subobscura is presented. The alcohol dehydrogenease locus was used as a genetic marker. Behavioral differences among the sexes and genotypes may explain these observations, although the molecular basis remains obscure.     

Teratogenic effect of trifluoperazine in rats and mice

Trifluoperazine was administered to pregnant mice and rats by gastric intubation during the period of organogenesis. Dams were treated at doses of 0.5, 5, 50 (mice and rats) and 100 (only rats) mg/kg/day. The drug affected the pregnant weight increment in a dose-related manner in rats but only the 50 mg/kg/day dose level affected the weight gain of mice. The foetal weight was not markedly affected in either species. The drug induced cleft palate and micrognathia in rats but did not produce a teratogenic effect in mice. Trifluoperazine caused abortions in mice and there were significant increases in the number of resorptions with the top dose levels in both species.     

Rhodotorula nothofagi sp. nov., isolated from decayed wood in the evergreen rainy Valdivian forest of southern Chile

An unusual Rhodotorula isolated from decayed wood of Nothofagus obliqua (Mirb.) Blume is described and illustrated. This species differs from all accepted Rhodotorula species (1–7, 10) to warrant its establishment as a new species, Rhodotorula nothofagi sp. nov.Postgraduate student from the Instituto de Ecología y de Evolución, Universidad Austral de Chile, Valdivia.     

Modification of the gene 5 DNA unwinding protein with ruthenium

A chemical modification of the gene 5 DNA binding protein (G5BP) from bacteriophage fd was investigated using X-ray diffraction and difference Fourier analysis. The crystalline protein was reacted with pentaammineruthenium (III) trichloride, Ru(NH₃)₅Cl₃, a reagent believed specific for histidine residues and useful in NMR and chemical modification studies of proteins. The major ruthenium site was found by difference Fourier analysis to be 4 Å from histidine 64, the only histidine residue in the molecule. A second bipartite site, believed to be a ruthenium-anion pair, appeared to be salt-bridged to glutamic acid 40 and arginine 16. Indications were present in the difference Fourier results to suggest that the loop containing tyrosine 41 had undergone a slight conformational rearrangement to accommodate this interaction.     

Metabolic response to ethanol and isopropanol in D. funebris and D. immigrans

Ethanol at low concentration increases larval viability in D. funebris and D. melanogaster and decreases it in D. immigrans. Isopropanol decreases viability in all three species. Isopropanol depresses alcohol dehydrogenase activity. This is accompanied by a change in the relative proportion of electrophoretic forms of the enzyme. Acetone appears in the medium when larvae of D. funebris and D. immigrans develop in the presence of isopropanol. It can be transformed again into isopropanol on reaching a threshold value. It seems that this transformation cannot be carried out by alcohol dehydrogenase alone.     

Phylogenetic relationships in the family Resedaceae L.

A study was made on the phylogenetic relationships of species of the family Resedaceae, based on morphological features, chromosome meiotic behaviour, karyotype features, size and fertility of pollen grains, nucleotypic parameters, seed protein profiles and esterase isozyme patterns.For the comparison of the seed protein profiles among species a method was developed based on the presence or absence of the bands by means of a computer program. The dendrogram obtained by such a method is in line, to a great extent, with the clusters (sections) obtained within the family based on morphological features.Data on meiotic behaviour and on morphology, such as the type of fruit, carpel numbers and others, suggest that x=5 is the primitive basic chromosome number of this family. x₁=6 and x₂=7 are considered as secondary basic numbers derived from x=5 through aneuploid changes.The results support a proposed phylogenetic tree of the genera and sections of the genus Reseda represented in the European Flora.The principal phenomena that have operated in the evolution of the Resedaceae seem to be aneuploid changes, polyploidy and structural rearrangements. A trend towards DNA increase in the evolution of this group is also apparent.     

Life-cycle and karyology of Branchiura sowerbyi Beddard (Oligochaeta,Tubificidae)

Data on the life-cycle of a population of Branchiura sowerbyi Beddard in a water-lily tank at the Botanical Garden in Padua are reported. The breeding period is from April to July, after which the reproductive system is partially resorbed (August–September) and reformed later in the autumn. The karyology of the species was also studied, and revealed 38 mitotic chromosomes in the gonia, and 19 bivalents in the primary spermatocytes and in the primary oocytes.     

Antagonism of diazepam-induced feeding in rats by antisera to opioid peptides

Diazepam-induced feeding in rats is antagonized not only by the opiate antagonist naloxone but also intraventricular administration of specific antisera to the endogenous opioid peptides met-enkephalin or beta-endorphin. Pituitary beta-endorphin is probably not implicated in the diazepam effect since blockade with the glucocorticoid dexamethasone of the release of beta-endorphin from the anterior pituitary does not modify the diazepam-induced feeding, which is however prevented by TRH, a suggested physiological antagonist of some of the effects of opioid peptides. The possible central participation of both beta-endorphin and met-enkephalin in the ingestive behavior induced by diazepam gives further support to the postulated physiological role of endogenous opioids in appetite regulation.     

Addition of an androgen-free epididymal protein extract increases the ability of immature hamster spermatozoa to fertilize in vivo and in vitro

The fertility of spermatozoa from the different epididymal segments of hamsters was tested by in-vivo insemination. Caput and proximal corpus spermatozoa were non-fertile; spermatozoa from the distal corpus epididymidis fertilized 13% (38/290) oocytes and those from the proximal and distal cauda epididymidis 71 and 87%, respectively. When tested by in-vitro insemination, distal corpus spermatozoa penetrated 44% of oocytes while those from the distal cauda fertilized 87% of oocytes. Spermatozoa from the distal corpus recovered in Medium BMOC fertilized 13% (28/219) of oocytes in vivo, while those mixed with an epididymal protein preparation (0.8 mg protein/ml) fertilized 24% (49/204; P less than 0.01) of oocytes. When distal corpus spermatozoa were inseminated in vivo with 0.8 mg epididymal protein preparation 34% (31/90) oocytes were fertilized and only 22% (23/103; P less than 0.05) oocytes were fertilized when the proteins were obtained from epididymides of animals castrated for 30 days. When distal corpus spermatozoa were preincubated for 5 h in medium without (control) or with protein preparation (0.8 or 1.6 mg protein/ml), a significant increase in in-vitro oocyte penetration was found (25 compared with 45%; P less than 0.05) when the protein was present at 1.6 mg/ml. These results confirm and extend previous observations suggesting a role for androgen-dependent glycoproteins secreted by the epididymis in the acquisition of fertilizing ability that occurs during sperm maturation.