Long-acting contraceptive agents: Norethisterone esters of arylcarboxylic acids

The synthesis of esters of norethisterone (17α-ethynyl-17β-hydroxy-estr-4-en-3-one) with acids containing a benzene ring is described, two methods of esterification being compared in terms of yield and convenience. The activities of these esters as long-acting contraceptive agents have been evaluated.     

Long-acting contraceptive agents: norethisterone esters of monoalkenyl and monoalkynyl acids

The synthesis of nine new esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) is described, with the esterifying acids bearing an acetylenic or olefinic function in a chain of eight or nine carbon atoms, for evaluation as long-acting contraceptive agents.     

The steroids and fatty acids of the basidiomycete Scleroderma polyrhizum

The fruit bodies of the Basidiomycete Scleroderma polyrhizum have been shown to contain the steroids ergosta-4,6,8(14) 22-tetraen-3-one and 5α,8α-epidoxyergosta-6,22-dien-3β-ol and also palmitic and oleic acids.     

Fertility interactions in Drosophila: Theoretical model and experimental tests

The results of 11 experiments with Drosophila species show that fertility is not a reducible property: the fertility of a mating pair cannot be predicted from the average fertility of the two genotypes involved. We propose a model of fertility selection that does not assume additivity (or multiplicativity) but assumes random mating and that the genotypic frequencies are in Hardy-Weinberg equilibrium. Numerical simulations show that removal of the assumption of Hardy-Weinberg frequencies does not significantly change the equilibrium frequencies predicted by the model.     

Identification of the membrane component of the anion pump encoded by the arsenical resistance operon of R-factor R773

The arsenical resistance (ars) operon of the conjugative R-factor R773 encodes an ATP-driven anion extrusion pump, producing bacterial resistance to arsenicals. There are three structural genes, of which the product of the middle gene, arsB, has not previously been identified. From nucleotide sequence data, the ArsB protein is predicted to be a 45577 Dalton hydrophobic protein. A mini-Mu transposition procedure was used to construct an arsB-lacZ gene fusion, producing a hybrid ArsB-beta-galactosidase protein which was localized in the inner membrane. The operon was cloned into a T7 RNA polymerase expression vector. In addition to the previously identified ArsA and ArsC proteins, the cells synthesized an inner membrane protein with an apparent mass of 36 kD identified as the ArsB protein.     

Mitochondrial DNA evolution in theDrosophila nasuta subgroup of species

Summary TheDrosophila nasuta group consists of about 12 closely related species distributed throughout the Indo-Pacific region. They are of great interest because of their evolutionary idiosyncrasies including little morphological differentiation, the ability to intercross in the laboratory often producing fertile offspring, and substantial chromosomal evolution. Studies of metric traits, reproductive isolation, and chromosomal and enzyme polymorphisms have failed to resolve the phylogeny of the species. We report the results of a survey of the mitochondrial DNA (mtDNA) restriction patterns of the species. The phylogeny obtained is consistent with other available information and suggests thatD. albomicans may represent the ancestral lineage of the group. The amount of polymorphism in local populations (=1.0% per site) is within the typical range observed in other animals, includingDrosophila. The degree of differentiation between species is, however, low: the origin of the group is tentatively dated about 6–8 million years ago. This study confirms the usefulness of mtDNA restriction patterns for ascertaining the phylogeny of closely related species.