The chemical-transformation products of 1,6-dibromo-1,6-dideoxygalactitol and 1,2:5,6-dianhydrogalactitol in aqueous solution

After hydrolysis of 1,6-dibromo-1,6-dideoxygalactitol (1) and 1,2:5,6-dianhydrogalactitol (2), 11 compounds were isolated, three of them as tritylated derivatives. Their structures were established on the basis of chemical evidence and, for four compounds, by X-ray diffraction. The main product of the hydrolysis of 1 was 3,6-anhydro-1-bromo-1-deoxy-dl-galactitol; the end-products of the hydrolysis of 2 were 1,5-anhydro-dl-galactitol, 2,5-anhydro-dl-altritol, and galactitol.     

Economic incentives for conservation: beekeeping and Saturniidae caterpillar utilization by rural communities

The economic viability of the wildlife based enterprises (bee-keeping and caterpillar utilization) in Malawi is discussed in relation to conventional agricultural enterprises (maize, beans and ground-nuts). A strong incentive emerges for rural people to adopt wildlife management as an adjunct to subsistence agriculture, and therefore, to promote conservation of natural ecosystems and wildlife habitats in the face of growing human population and demand for land. Dependence on agriculture has depleted the wildlife resource outside protected areas and has been less effective in improving the wealth and living standards of most rural people. This study illustrates that the Malawi Department of National Parks and Wildlife needs to introduce economic incentives that integrate biological conservation with economic development for the rural people. The management programme involves the adoption of a rotation burning policy that promotes vegetation coppicing, eases harvesting and promotes high caterpillar yields.     

Polymorphism due to variable number of repeats in the human involucrin gene.

The coding region of the involucrin gene in higher primates contains a segment consisting of numerous tandem repeats of a 10-codon sequence. The process of repeat addition began in a common ancestor of all higher primates and subsequent repeats were added vectorially. As a result, the principal site of repeat addition has moved in the 3' to 5' direction and the most recently generated repeats (the late region) are close to the 5' end of the segment of repeats. In the human, most of the late region is made up of two different blocks, each consisting of nearly identical repeats. We describe here five polymorphic forms resulting from the addition of differing numbers of repeats to each block. As the variety and nature of the polymorphic alleles are different in different human populations, we postulate that the process of repeat addition is genetically determined.     

Substrate analogue induced changes of the CO-stretching mode in the cytochrome P450cam-carbon monoxide complex.

The CO-stretching mode of the carbon monoxide ligand in reduced cytochrome P450cam, in the absence or presence of camphor and in the presence of nine different camphor analogues, was measured at room temperature using Fourier transform infrared spectroscopy. Substrate-free cytochrome P450cam--CO reveals a broad, slightly structured band resulting from an overlap of several stretching mode signals. The multitude of the signals indicates that cytochrome P450 exists in a dynamic equilibrium of several conformational substates. Binding of camphor or camphor analogues strongly influences this equilibrium. For substrate analogues which are not able to form a hydrogen bond to the hydroxyl group of tyrosine 96, the CO-stretching band is rather broad and asymmetric. In contrast, substrate analogues with one quinone group which form a hydrogen bond to the Tyr96 OH induce a shift and a sharpening of the CO-stretching mode band. For substrate analogues with two hetero groups, the infrared spectrum is slightly asymmetric or a minor band appears. Sterical hindrance, substrate mobility, and protein flexibility finally determine the position and width of the CO-stretching mode signals.