Effects of the antiandrogen cyproterone acetate on reproduction in male and female ring doves

The present experiment was designed to study the role of increased plasma androgens which are seen in male and female doves during courtship. In pairs of doves either the male or female was injected daily with oil or with 6 or 15 mg of cyproterone acetate (CA), starting 3 days before pairing. Cyproterone acetate at both dose levels reduced the amount of bow-cooing shown by the male on the day of pairing, and at the higher dose resulted in a reduction of nest soliciting by injected males and their untreated mates over the 7 days of testing. At the high dose only, the size of the testes was reduced. In pairs where females received CA, there was a decrease in levels of nest soliciting by both partners and ovarian development was blocked. The results are discussed in terms of the possible significance of fluctuating androgen levels found in doves during the prelaying period.     

Self-induced water intoxication in a schizophrenic patient.

Water intoxication occurred in a 53-year-old woman with chronic simple schizophrenia and poorly controlled diabetes. For several years she had had a compulsive habit of drinking excessive amounts of water. Coma, fever, convulsions and other neurologic signs appeared suddenly, and she had severe hyponatremia. Her condition improved rapidly when the electrolyte abnormality was corrected.     

Influence of microclimate and species interactions on the composition of plant and invertebrate communities in alpine northern Norway

We assessed the effects of both biotic processes and abiotic factors on the community composition of vascular plant species and invertebrates at a site in northern Norway. Plant species were assigned to functional (woody versus herbaceous) and biogeographic (boreal versus alpine) groups. Invertebrate species were classified as either herbivore or predator. When species interactions and effects of the abiotic environment were partitioned, boreal species appeared to influence the distribution of alpine species and woody species the distribution of herbaceous species. Analysis of partial correlations indicated that facilitation was the dominant mode of interaction between the two pairs of plant groups. Among abiotic factors, the thermal environment probably influenced all components of the plant and invertebrate communities, except for predatory invertebrates, and wind appeared important in determining the composition of woody and alpine components of the plant community but not the herbaceous component. The composition of the boreal component of the plant community apparently influenced the composition of all invertebrate communities, except for predatory invertebrates. The composition of the woody component of the plant community influenced the composition of both herbivore and predator communities. The alpine plant-community composition influenced predatory invertebrate community composition. Woody plant community composition influenced the composition of both herbivore and predator communities. Our analytic approach, based on two kinds of structural equation models (d-separation and path analysis), provides a useful method for identifying the biotic as well as abiotic factors that influence community structure.     

Structure-function analyses of the ATX1 metallochaperone.

Saccharomyces cerevisiae Atx1p represents a member of the family of metallochaperone molecules that escort copper to distinct intracellular targets. Atx1p specifically delivers copper to the Ccc2p copper transporter in the Golgi. Additionally, when overproduced, Atx1p substitutes for superoxide dismutase 1 in preventing oxidative damage; however the mechanistic overlap between these functions is unresolved. The crystal structure of Atx1p has been solved recently. By examining a surface electrostatic potential distribution, multiple conserved lysines are revealed on one face of Atx1p. An additional conserved lysine (Lys65) lies in close proximity to the metal binding site. Through site-directed mutagenesis, residues in the metal binding region including Lys65 were found to be necessary for both copper delivery to Ccc2p and for Atx1p antioxidant activity. Copper trafficking to Ccc2p also relied on the lysine-rich face of Atx1p. Surprisingly however, elimination of these lysines did not inhibit the antioxidant activity of Atx1p. We provide evidence that Atx1p does not suppress oxidative damage by a metallochaperone mechanism but may directly consume superoxide. Purified Cu-Atx1p reacts noncatalytically with superoxide anion in vitro. We conclude that the copper-trafficking and antioxidant functions of Atx1p arise from chemically and structurally distinct attributes of this metallochaperone.