Polymorphisms in mitochondrial DNA of European and Africanized honeybees (Apis mellifera)

This study demonstrates polymorphisms in both the length and in the restriction enzyme cleavage sites of honeybee mitochondrial DNA (mtDNA). The levels of variation are typical of those found in other metazoan species. These polymorphisms are potentially useful for the identification of Africanized bees in the western hemisphere and for study of honeybee phylogenetics.     

Vanadium biochemistry: The unknown role of vanadium-containing cells in ascidians (sea squirts)

Summary This article reviews several new developments in vanadium biochemistry, as elucidated from studies of ascidians. A hypothesis correlating ascidian blood cell function to anaerobiosis, via two prominent redox constituents, namely vanadium(III) and the tunichromes, a family of metal ion complexing/reducing hydroquinonoid peptides, is presented.     

The performance of the octopus circulatory system: A triumph of engineering over design

Summary Despite the very considerable difficulties presented by the basic molluscan anatomy and the possession of a blood pigment with an oxygen carrying capacity that never exceeds 4.5 vols%, the cephalopod circulatory system contrives to deliver oxygen at a rate fully comparable with that of an active fish. This is achieved by adding accessory pumps to push blood through the gills, by a multiplicity of pulsatile veins and by raising the systemic blood pressure considerably above the levels found in other molluscs. Detailed control of blood distribution is a necessity in a system where the peripheral resistences may be expected to change dramatically when the animal starts to move and large parts of the central nervous system are apparently dedicated to this task. In this account we have reviewed blood pressure and flow at rest and in exercise. We have further examined the evidence which indicates how the animals modulate the cardiac output, drawing attention to the very different response found in cephalopods and the higher vertebrates.     

Gigantecin: a novel antimitotic and cytotoxic acetogenin, with nonadjacent tetrahydrofuran rings, from Goniothalamus giganteus (Annonaceae)

Gigantecin (I), a novel tetrahydroxy-di-tetrahydrofuran fatty acid gamma-lactone (acetogenin), was isolated from an ethanolic extract of the stem bark of Goniothalamus giganteus Hook. f., Thomas (Annonaceae), by means of activity-directed fractionation (brine shrimp lethality test). This new compound is extremely cytotoxic to human tumor cells, inhibits crown gall tumors on potato discs, and is active in an assay designed to detect antimitotic agents (9 ASK).