Bifunctional cosmid vector forStreptomyces

Summary AnEscherichia coli/Streptomyces bifunctional cosmid vector, pJP3, which selects for clones with insert size 23–33 kilobase pairs (kb), has been constructed. A genomic DNA library fromS. kanamyceticus has been stably maintained inE. coli using pJP3. This recombinant DNA can be transferred intoS. lividans with increased efficiency by utilizing heat treatment during protoplast formation.     

Overexpression of the Neurotrophic Cytokine S100β in Human Temporal Lobe Epilepsy

Abstract: Neuritic sprouting and disturbances of calcium homeostasis are well described in epilepsy. S100β is an astrocyte-derived cytokine that promotes neurite growth and induces increases in levels of intracellular calcium in neurons. In sections of neocortex of surgically resected temporal lobe tissue from patients with intractable epilepsy, we found that the number of S100β-immunoreactive astrocytes was approximately threefold higher than that found in control patients ( p < 0.001). These astrocytes were activated, i.e., enlarged, and had prominent processes. Temporal lobe tissue levels of S100β were shown by ELISA to be fivefold higher in 21 epileptics than in 12 controls ( p < 0.001). The expression of the astrocyte intermediate filament protein, glial fibrillary acidic protein, was not significantly elevated in epileptics, suggesting a selective up-regulation of S100β expression. Our findings, together with established functions of S100β, suggest that this neurotrophic cytokine may be involved in the pathophysiology of epilepsy.     

Regulation of rat liver microsomal cholesterol 7 alpha-hydroxylase: presence of a cytosolic activator

Microsomal cholesterol 7 alpha-hydroxylase (EC 1.14.13.7) in rat liver was assayed by a single-isotope-incorporation method, and factors influencing its activity were studied. Crude cytosol contained a non-catalytic activator which was heat-stable and on-dialyzable. This activator enhanced cholesterol 7 alpha-hydroxylase catalytic activity. The stimulatory property of this cytosolic activator was not altered by cholestyramine feeding, and was retained after fractionation by ammonium sulfate of saturation up to 65%. 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) stimulated hydroxylase activity at concentrations up to 90 micro M. ATP at concentration greater than 1.2 mM inhibited hydroxylase activity. NaF was stimulatory at concentrations up to 50 mM with a maximum stimulatory effect at 10 mM, and was antagonistic in effect to ATP. HMG-CoA and ATP at the above inhibitory concentrations and higher abolished the activating effect of the cytosolic factor.     

An apparatus for immunoelectrofocusing. A study of squid tyrosinase.

An apparatus which facilitates immunoelectrofocusing is described. Polyacrylamide is used as the support medium for both the thin-layer isoelectric focusing and immunodiffusion stages. The pH gradients formed during electrofocusing are reproducible and sufficiently stable. Immunoelectrofocused and isoelectric focused patterns indicate that at least one inactive form and four active forms of squid tyrosinase exist.     

Parrot conservation and ecotourism in the Windward Islands

The genus Amazona is represented on three islands in the Windward Islands. Since Europeans first visited the region in the fifteenth century, at least three parrot species have become extinct in the Windward Islands, and today all the extant parrots of the region are endangered. Several factors have contributed to the current plight of the parrots. The authorities in each of the islands of the Windward Islands that have endemic parrots have come to the realization that sound environmental management measures can complement rather than hinder national socioeconomic goals and objectives. Consequently, regional governments have begun to explore and foster linkages between conservation and other sectors of the economy. This article examines current parrot conservation efforts in the Windward Islands and the linkages which are being fostered between tourism and other sectors of the economy. Policy and research implications of the region's current parrot conservation efforts and ecotourism programme are also considered.