We studied host selection and exploitation, two crucial aspects of parasite ecology, in Achrysocharoides parasitoid wasps, which show remarkable host specificity and unusual offspring sex allocation. We estimated a molecular phylogeny of 15 Achrysocharoides species and compared this with host (plant and insect) phylogenies. This tri-trophic phylogenetic comparison provides no evidence for cospecia

Acetohydroxyacid synthase (AHAS) is the target enzyme for a number of herbicides. A S653N mutation in the AHAS gene results in an increased tolerance to imidazolinone herbicides. We have investigated the use of the mutated gene as selection gene for potato transformation. This resulted in a transformation system with a very high transformation frequency and low rate of escapes. The mutated AHAS ge

HIV particles that use the chemokine receptor CXCR4 as a coreceptor for entry into cells (X4-HIV) inefficiently transmit infection across mucosal surfaces [1], despite their presence in seminal fluid and mucosal secretions from infected individuals [2] [3] [4]. In addition, although intestinal lymphocytes are susceptible to infection with either X4-HIV particles or particles that use the chemokine

The use of valproic acid during human pregnancy increases the risk of hypospadias in the offspring. Rats exposed in utero to valproic acid did not develop hypospadias and even had a slightly increased anogenital distance in males 3-4 days after birth. A classical antiandrogenic drug, flutamide, caused hypospadias as well as a reduction of the anogenital distance in males. At the age of 3 months, r

Despite the growing evidence that elevated total homocysteine (tHcy) in plasma is a cardiovascular risk factor, the mechanism underlying the vascular injury is still unknown. Studies are difficult due to the fact that little is known about the formation of different homocysteine species in vivo. In the present study we have investigated the different fractions of tHcy in 21 patients with acute cor

At evaluation of contact dermatitis caused by solid material, patch testing is usually performed with the material as such and with extracts of it. In this study, optimization of the extraction technique monitored by quantitative HPLC analysis of the extracted haptens is described for mercaptobenzothiazole derivatives. Several solvents with different properties are included. Acetone has traditiona

The relationships among cellular nutrient status, environmental conditions (temperature and nutrient availability), and cyst production were studied in batch cultures of three cold-water dinoflagellates (Scrippsiella hangoei, Gymnodinium corollarium, and Woloszynskia halophila) isolated from the Baltic Sea. We tested the effect of increasing temperature while providing nutrient-replete conditions

The theory of sexual conflict predicts that sexual coevolution will be very dynamic, with in principle perpetual evolutionary arms races and chases. These arms races are expected to stop once the costs of conflict adaptations become too high. We argue that this prediction is contingent on specific assumptions about the sexual interaction and the adaptations involved in the arms race. More generall

During ultrafiltration (UF), the driving force along the membrane is diminished due to concentration increase and frictional pressure drop. In most applications of ultrafiltration the influence of the frictional pressure drop is negligible. However, when treating concentrated, viscous liquids the frictional pressure drop can reduce the transmembrane pressure (TMP) significantly. The influence of c

The binding of iodine-labelled plasminogen to Helicobacter pylori CCUG 17874 was characterized. Inhibition of the binding was observed after preincubation of H. pylori cells with nonradiolabelled plasminogen, lysine, or the lysine analogue -aminocaproic acid. Fragments of plasminogen, kringles 1 to 3, kringle 4, and mini-plasminogen, were also studied as potential inhibitors. Mini-plasminogen caus

The paper provides new information on morphological characters which are useful in generic diagnostics of the Proisotoma complex of Isotomidae. Based on this information, a number of known species are excluded from the redefined Proisotoma s. str. and moved to the genus Scutisotoma Bagnall, 1949, which is again given generic status. The following genera are given more precise definitions: Subisoto

l-DOPA-induced dyskinesia (LID) is a major complication of the pharmacotherapy of Parkinson's Disease. A model of LID has recently been described in rats with unilateral 6-hydroxydopamine (6-OHDA) lesions. In the present study, the model was used in order to compare the efficacies of some clinically available compounds that have shown antidyskinetic effects in nonhuman primate models of LID and/or

We present an approach for proving the global existence of classical solutions of certain quasilinear parabolic systems with homogeneous Dirichlet boundary conditions in bounded domains with a smooth boundary. (C) 2003 Elsevier Inc. All rights reserved.

Information is a crucial currency for animals from both a behavioural and evolutionary perspective. Adaptive behaviour relies upon accurate estimation of relevant ecological parameters; the better informed an individual, the better it can develop and adjust its behaviour to meet the demands of a variable world. Here, we focus on the burgeoning interest in the impact of ecological uncertainty on ad

The Drosophila melanogaster deoxyribonucleoside kinase (Dm-dNK) double mutant N45D/N64D was identified during a previous directed evolution study. This mutant enzyme had a decreased activity towards the natural substrates and decreased feedback inhibition with dTTP, whereas the activity with 3'-modified nucleoside analogs like 3'-azidothymidine (AZT) was nearly unchanged. Here, we identify the mut

Simulations of future tropospheric composition often include substantial increases in biogenic isoprene emissions arising from the Arrhenius-like leaf emission response and warmer surface temperatures, and from enhanced vegetation productivity in response to temperature and atmospheric CO2 concentration. However, a number of recent laboratory and field data have suggested a direct inhibition of le