Electroantennogram response of alfalfa seed chalcid,Bruchophagus roddi (Hymenoptera: Eurytomidae) to host- and nonhost-plant volatiles.

The alfalfa seed chalcid (ASC),Bruchophagus roddi, is a monophagous pest of alfalfa that parasitizes developing seeds. To further understand the olfactory basis of host-plant recognition by ASCs, we recorded electroantennograms (EAGs) from females and males to 39 volatiles from both alfalfa and red clover. The chemoreceptive sensitivity of ASCs was selective for certain general classes of compounds, defined by their carbon-chain length (C6 and C8), structure (aliphatics and phenolics), isomerism, and/or functional group (acetates, ketones, and alcohols).

The radical experiment: transforming Britain's national health system to interlocking markets.

The reforms of Britain's National Health Service (NHS) are the most sweeping attempt in the world to transform a social system of administered services into a system of buyers and sellers. At issue are basic questions about the nature of human behavior and the nature of inefficiency. This article outlines the NHS and its problems, shows how narrow and misleading the market-based diagnosis was of those problems, explains the reforms, and assesses their likely impact.

Intravenous recombinant soluble human thrombomodulin prevents venous thrombosis in a rat model.

Thrombomodulin is an endothelial surface thrombin receptor. Thrombin bound to thrombomodulin loses all procoagulant activity and instead activates the protein C anticoagulant pathway. We developed a recombinant thrombomodulin analog and compared the effects of recombinant thrombomodulin (100 micrograms/ea), saline (controls), recombinant hirudin (1.

Cloning and Sequencing of the cDNA Encoding the Rubber Elongation Factor of Hevea brasiliensis.

In Hevea brasiliensis, the rubber particle in the laticiferous vessel is the site of rubber (cis-1-4-polyisoprene) biosynthesis. A 14 kilodalton protein, rubber elongation factor (REF), is associated with the rubber particle in a ratio of one REF to one rubber molecule (Dennis M, Henzel W, Bell J, Kohr W, Light D [1989] J Biol Chem 264: 18618-18628; Dennis M, Light D [1989] J Biol Chem 264: 18608-18617). To obtain more information concerning the function of REF and its synthesis and assembly in the rubber particle, we isolated cDNA clones encoding REF.

Biting hard on the research bit.

Underfunding can be a major source of waste argues Donald Light in the fourth of a five part series of articles as he identifies some systemic inefficiencies.

Labelling waste as inefficiency.

In the third of a five part series of articles, Donald Light goes in search of justification for the sweeping changes affecting the NHS and finds that the current reforms ignore some basic problems.

Bending the rules.

It is naive to claim that competition leads to efficiency, warns Donald Light. In the second of five articles, he describes how sellers have manipulated the US healthcare market.

Learning from their mistakes?

Embracing competition American style could turn out to be an expensive mistake, says Donald Light. In the first of a series of five articles he explains how bad advice and underfunding could turn the American dream into a British nightmare.

A GTP-binding protein activates chloride channels in a renal epithelium.

Although G proteins have been shown to regulate cation channels, regulation of Cl- channels by G proteins has not been demonstrated directly. Accordingly, the objective of this study was to examine whether a G protein regulates Cl- channels in the apical membrane of rabbit kidney CCD cells grown in culture. Previous studies showed that this channel is activated by adenosine and protein kinase C and has a single channel conductance of 305 picosiemens.

Dual ion-channel regulation by cyclic GMP and cyclic GMP-dependent protein kinase.

Atrial natriuretic peptide, acting through its second messenger guanosine 3',5'-cyclic monophosphate (cGMP), suppresses Na+ absorption across the renal inner-medullary collecting duct and increases urinary Na+ excretion. Patch clamp studies show that cGMP reduces Na+ absorption by inhibiting an amiloride-sensitive cation channel in the apical membrane. We have now examined, using the patch clamp technique, the molecular mechanisms of cGMP inhibition.

The human growth hormone receptor. Secretion from Escherichia coli and disulfide bonding pattern of the extracellular binding domain.

A gene fragment encoding the extracellular domain of the human growth hormone (hGH) receptor from liver was cloned into a plasmid under control of the Escherichia coli alkaline phosphatase promoter and the heat-stable enterotoxin (StII) signal peptide sequence. Strains of E. coli expressing properly folded hGH binding protein were identified by blotting colonies with 125I-hGH.

Chloride channels in the apical membrane of cortical collecting duct cells.

Ion channels in the apical membrane of cortical collecting duct (CCD) cells in culture were studied by the patch-clamp technique. CCD cells from rabbit kidney were isolated by solid-phase immunoadsorption with a monoclonal antibody. The majority of CCD cells (93%) had phenotypic characteristics similar to intercalated cells (ICC).

Amino acid sequence of rubber elongation factor protein associated with rubber particles in Hevea latex.

The amino acid sequence of rubber elongation factor, a recently discovered protein tightly bound to rubber particles isolated from the commercial rubber tree Hevea brasiliensis, is presented. The role of this protein in rubber elongation and its interaction with prenyltransferase and rubber particles have been discussed in the preceding paper in this series (Dennis, M. S.

Rubber elongation by farnesyl pyrophosphate synthases involves a novel switch in enzyme stereospecificity.

A prenyltransferase purified from the commercial rubber tree, Hevea brasiliensis, that elongates existing cis-polyisoprene rubber molecules also catalyzes the formation of all trans-farnesyl pyrophosphate (t,t-FPP) from dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP). In assays of the latter activity trans-geranyl pyrophosphate is the only other product identified. In contrast to this limited addition of IPP to DMAPP, we measured 7000 additions of isoprene per rubber molecule in a previous titration of active allylic ends of rubber molecules by purified prenyltransferase (Light, D.