Activities of alkaline phosphatase in first trimester chorion biopsy tissue

We have determined the activity of alkaline phosphatase in chorionic villous tissue obtained in the first trimester of pregnancy, in order to obtain the normal range of values as a prerequisite for application to the prenatal diagnosis of the rare bone disease hypophosphatasia. The activities found were a combination of intestinal and liver/bone/kidney types; traces of placental type were present in only one sample.     

Radio-telemetric evidence of migration in the gregarious but not the solitary morph of the Mormon cricket (Anabrus simplex: Orthoptera: Tettigoniidae)

 The Mormon cricket, Anabrus simplex, is one of just a few species of katydids (or bushcrickets, Orthoptera: Tettigoniidae) that, like migratory locusts, appear to have solitary and migratory morphs. Using radio telemetry we studied movements of individuals of two morphs of this flightless species. Individuals within each migratory band had similar rates of movements along similar directional headings whereas solitary individuals moved little and showed little evidence of directionality in movement. Our results also add to other recent radio-telemetry studies showing that flightless insects of 1–2 g in mass can be tracked successfully using these methods. Received: 28 February 2000 / Accepted in revised form: 19 June 2000     

Hopanoid Biosynthesis and Function in Bacteria

   Hopanoids are pentacyclic triterpenoid lipids occurring in bacteria. They are synthesized from isopentenyl units which are formed in a new biosynthetic route leading to isopentenyl diphosphate. Six C₅ units are joined to form squalene, the immediate precursor in hopanoid synthesis. In a highly complex cyclization reaction that shares considerable similarities with that of oxidosqualene to sterols, the hopane skeleton is formed from squalene by the squalene-hopene cyclase. Recent elucidation of the X-ray structure of this membrane-bound cyclase has shed some light on the properties of this unusual enzyme. The active site is located in a cavity within the enzyme. The squalene substrate diffuses through a channel structure from the membrane into this cavity and is there transformed into hopene. Polar side chains are attached to hopene resulting in the amphiphilic molecular structure of many hopanoids. These hopanoids are membrane components involved in regulating membrane fluidity and stability. However, the many structural variants of hopanoids indicate that they may have other interesting but as yet unknown functions.     

莫桑比克的海洋生物学研究:过去、现在及未来

本文概述了莫桑比克包括渔业在内的海洋生物学研究的发展情况.莫桑比克的海岸线约为3000km,海洋的生物资源在莫桑比克的社会中起着重要的作用,主要是作为人们的蛋白质来源以及收入和出口创汇的来源.