Crystallization and preliminary X-ray analysis of three serotypes of foot-and-mouth disease virus.

Foot-and-mouth disease viruses from serotypes O, A and C have been crystallized. The particular strains studied include O1K, A10(61), A22 Iraq 24/64, A24 Cruzeiro and C-S8c1. In addition, crystals have been grown of G67, a monoclonal antibody neutralization escape mutant derived from O1K, and of virus R100, recovered after the establishment of a persistent infection in baby hamster kidney cells with C-S8c1. Empty particles, capsids which lack the RNA genome, have also been crystallized for subtypes A22 Iraq 24/64 and A10(61). In almost all cases, crystals suitable for high resolution structure determination were obtained from (NH4)2SO4 or mixtures of polyethylene glycol and NH4Cl.     

A rapid method to screen fungi for resistance to toxic chemicals

Although many species of fungi are able to degrade highly toxic chemicals, only a few species have been evaluated for resistance to toxic effects of these chemicals. In this paper we demonstrate the successful application of a method to rapidly screen several species of fungi for toxicity to chemicals or mixtures of chemicals using pentachlorophenol (PCP) as a model toxic compound. Cellulose antibiotic assay disks were soaked in solutions containing different concentrations of PCP (5, 10, 25, 50, and 80 mg l^–1) and then placed in a triangular pattern outside the growing edge of the mycelia of eighteen species of white rot fungi. The plates were incubated and observed for development of inhibition zones (non-growth areas) around the disks. The short-term (24 h) growth of all eighteen species of fungi was inhibited by 5–10 mg-PCP l^–1, a range similar to that observed using previously reported techniques. Long-term growth studies using this screening method were not useful since PCP diffused from the disk into the agar, decreasing the applied dose.     

Divergent Androgen Receptor and Beta-Catenin Signaling in Prostate Cancer Cells

Despite decades of effort to develop effective therapy and to identify promising new drugs, prostate cancer is lethal once it progresses to castration-resistant disease. Studies show mis-regulation of multiple pathways in castration-resistant prostate cancer (CRPC), reflecting the heterogeneity of the tumors and also hinting that targeting androgen receptor (AR) pathway alone might not be sufficient to treat CRPC. In this study, we present evidence that the Wnt/β-catenin pathway might be activated in prostate cancer cells after androgen-deprivation to promote androgen-independent growth, partly through enhanced interaction of β-catenin with TCF4. Androgen-independent prostate cancer cells were more prone to activate a Wnt-reporter, and inhibition of the Wnt/β-catenin pathway increased sensitivity of these cells to the second-generation antiandrogen, enzalutamide. Combined treatment of enzalutamide and Wnt/β-catenin inhibitor showed increased growth repression in both androgen-dependent and -independent prostate cancer cells, suggesting therapeutic potential for this approach.     

Testosterone stimulates reproductive behavior during autumn in mockingbirds (Mimus polyglottos)

Mockingbirds normally secrete little or no testosterone during the period of autumnal territoriality. To determine the behavioral effects of exogenously administered testosterone, 20-mm lengths of Silastic tubing filled with crystalline testosterone were implanted into free-living resident mockingbirds during the autumn. Control residents were given sealed empty implants. Focal animal sampling showed that T-implanted males sang significantly more than controls. Perhaps as a consequence, a significantly greater percentage of the T-implanted males acquired mates. Though nest building does not naturally occur in autumn, T-implanted males also showed significantly more nest building than control males. However, T-implanted males only built if there was a female in the territory, suggesting a synergy between the presence of testosterone and social cues provided by the female. Examination of the effects of testosterone on territorial aggression showed that despite the high levels of territorial activity common in this species in autumn, territorial fights were unaffected by the presence of testosterone. One aggressive call, known to function in fall territorial defense, was significantly decreased in T-implanted versus control males. The presence of fall testosterone appears to stimulate a number of reproductive activities in mockingbirds, leaving autumnal aggressive interactions either unchanged or decreased. We discuss the application of these data to the effects of testosterone on the mockingbird's reproductive behavior during the breeding season.