Detection, identification and geographical distribution of European corn borer larval parasitoids using molecular markers.

Biological control requires specific tools for the accurate detection and identification of natural enemies, and to detect unusual variations in their density, which may follow changes in agricultural practices. Here we have developed specific molecular markers to detect Lydella thompsoni (Herting) and Pseudoperichaeta nigrolineata (Walker) (Diptera: Tachinidae) within the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae). Primers amplifying fragments of the mitochondrial COI gene were designed following alignment of comparable sequences for a range of parasitoid and host species.

Description and technical pitfalls of a hepatoma model and of intra-arterial injection of radiolabelled lipiodol in the rat.

Intra-arterial metabolic radiotherapy (using lipiodol labelled with iodine-131 or rhenium-188) is a therapeutic approach that can be used for the treatment of hepatocellular carcinomas (HCC). We propose a detailed description of the tumoral model using the N1-S1 cell line as well as a technique for intra-arterial injection of radiolabelled lipiodol in order to undertake preclinical studies necessary for the evaluation of a new molecule. We also report the principal technical pitfalls that were faced.

Effect of stabilized iodized oil emulsion on experimentally induced hepatocellular carcinoma in rats.

Purpose: Previous studies have shown that the use of Lipiodol UltraFluid (LUF) emulsified with water leads to an increase in the tumoral uptake of iodine I 131-labeled LUF and reduced pulmonary uptake. Although emulsions containing LUF are currently used for chemoembolization of hepatocellular carcinomas (HCCs), this approach is impossible with intraarterial radiation therapy (RT) because of the problems of radiation protection linked to instability of the emulsions. The aims of this study were to develop stabilized emulsions of radiolabeled LUF of different particle sizes and viscosities and to study its biodistribution in rats with HCC.

Regulating insect resistance management: the case of non-Bt corn refuges in the US.

In this paper, we analyze the insect resistance management (IRM) plan put in place by the US Environmental Protection Agency (EPA) to delay the evolution of resistance to Bt corn in natural populations of the European corn borer, Ostrinia nubilalis Hübner. This IRM plan is the most impressive mandatory IRM system ever developed. It forms a coherent whole and includes mandatory refuges, actions to increase growers' compliance and a program for monitoring the evolution of resistance.

Assortative mating in sympatric host races of the European corn borer.

Although a growing body of work supports the plausibility of sympatric speciation in animals, the practical difficulties of directly quantifying reproductive isolation between diverging taxa remain an obstacle to analyzing this process. We used a combination of genetic and biogeochemical markers to produce a direct field estimate of assortative mating in phytophagous insect populations. We show that individuals of the same insect species, the European corn borer Ostrinia nubilalis, that develop on different host plants can display almost absolute reproductive isolation-the proportion of assortative mating was >95%-even in the absence of temporal or spatial isolation.

Differences between rats and mice in the involvement of the aryl hydrocarbon receptor in 4-vinylcyclohexene diepoxide-induced ovarian follicle loss.

Repeated dosing with the occupational chemical 4-vinylcyclohexene diepoxide (VCD) selectively depletes small pre-antral follicles in the ovaries of rats and mice via apoptosis. The aryl hydrocarbon receptor (AhR) plays a role in mediating the effects of several xenobiotics. Therefore, this study was designed to investigate a potential role of the AhR in VCD-induced ovotoxicity.

Ostrinia nubilalis parasitism and the field abundance of non-target insects in transgenic Bacillus thuringiensis corn (Zea mays).

In this study, we evaluated in field trials the effects on non-target species, of transgenic corn producing the Cry1Ab toxin of Bacillus thuringiensis (Bt). In 1998, we collected Ostrinia nubilalis (Hübner) larvae from transgenic Bt corn (Novartis Hybrid 176) and non-Bt corn at four geographical sites. We found a significant variation in parasitism by the tachinids Lydella thompsoni (Herting) and Pseudoperichaeta nigrolineata (Walker) among sites, and more parasitism in non-Bt than in Bt fields.

Monitoring ligand-mediated nuclear receptor-coregulator interactions by noncovalent mass spectrometry.

Retinoid receptors are ligand-dependent transcription factors belonging to the nuclear receptor superfamily. Retinoic acid (RARalpha, beta, gamma) and retinoid X (RXRalpha, beta, gamma) receptors mediate the retinoid/rexinoid signal to the transcriptional machineries by interacting at the first level with coactivators or corepressors, which leads to the recruitment of enzymatically active noncovalent complexes at target gene promoters. It has been shown that the interaction of corepressors with nuclear receptors involves conserved LXXI/HIXXXI/L consensus sequences termed corepressor nuclear receptor (CoRNR) boxes.

Genetic isolation between two sympatric host plant races of the European corn borer, Ostrinia nubilalis Hubner. II: assortative mating and host-plant preferences for oviposition.

The European corn borer, Ostrinia nubilalis Hubner, colonized maize (Zea mays L.) after its introduction into Europe about 500 years ago and is now considered one of the main pests of this crop. In northern France, two sympatric host races have been described: one feeding on maize and the other on mugwort (Artemisia vulgaris L.

Characterization of the interaction between retinoic acid receptor/retinoid X receptor (RAR/RXR) heterodimers and transcriptional coactivators through structural and fluorescence anisotropy studies.

Retinoid receptors (RARs and RXRs) are ligand-activated transcription factors that regulate the transcription of target genes by recruiting coregulator complexes at cognate promoters. To understand the effects of heterodimerization and ligand binding on coactivator recruitment, we solved the crystal structure of the complex between the RARbeta/RXRalpha ligand-binding domain heterodimer, its 9-cis retinoic acid ligand, and an LXXLL-containing peptide (termed NR box 2) derived from the nuclear receptor interaction domain (NID) of the TRAP220 coactivator. In parallel, we measured the binding affinities of the isolated NR box 2 peptide or the full-length NID of the coactivator SRC-1 for retinoid receptors in the presence of various types of ligands.

Managing the evolution of Bacillus thuringiensis resistance in natural populations of the European corn borer, Ostrinia nubilalis: host plant, host race and pherotype of adult males at aggregation sites.

The European corn borer (ECB) consists of at least two, genetically differentiated host races: one feeding on maize, the other feeding on mugwort and hop. It is unclear to what extent individuals feeding on these, or other host plants, contribute to natural ECB populations. The mechanisms underlying the genetic differentiation between both races are not well understood; they may include sexual attraction via different pheromone blends (E or Z) and differences in the location of mating sites.

188Re-SSS lipiodol: radiolabelling and biodistribution following injection into the hepatic artery of rats bearing hepatoma.

Background: Although intra-arterial radiation therapy with 131I-lipiodol is a useful therapeutic approach to the treatment of hepatocellular carcinoma, various disadvantages limit its use.

Aim: To describe the development of a method for the labelling of lipiodol with 188Re-SSS (188Re (S2CPh)(S3CPh)2 complex) and to investigate its biodistribution after injection into the hepatic artery of rats with hepatoma.

Methods: 188Re-SSS lipiodol was obtained after dissolving a chelating agent, previously labelled with 188Re, in cold lipiodol.

Genetics of resistance to transgenic Bacillus thuringiensis poplars in Chrysomela tremulae (Coleoptera: Chrysomelidae).

The area under genetically engineered plants producing Bacillus thuringiensis (Bt) toxins is steadily increasing. This increase has magnified the risk of alleles conferring resistance to these toxins being selected in natural populations of target insect pests. The speed at which this selection is likely to occur depends on the genetic characteristics of Bt resistance.

Synthesis of furano-epothilone D.

The total synthesis of furano-epothilone D by a convergent route is reported. The key fragments are available on a large scale to provide sufficient material for biological evaluation. The approach involves a palladium-catalyzed coupling that generates a highly functionalized aldehyde which is connected in a stereoselective aldol reaction to yield the framework of furano-epothilone D.

A new mutation of the androgen receptor, P817A, causing partial androgen insensitivity syndrome: in vitro and structural analysis.

Androgen insensitivity syndrome (AIS) is an X-linked disease caused by mutations in the androgen receptor (AR) resulting in various degrees of defective masculinization in 46,XY individuals. In the present study, we describe a novel mutation in exon 7 of the AR gene in an Egyptian patient with partial AIS (PAIS). Sequencing analysis of the AR gene revealed a novel missense mutation, P817A, within the ligand-binding domain (LBD).

Purification and crystallization of the heterodimeric complex of RARbeta and RXRalpha ligand-binding domains in the active conformation.

The ligand-binding domains of the retinoid X receptor alpha (RXRalpha) and of the retinoic acid receptor beta (RARbeta) were overexpressed separately and copurified in the heterodimeric form. Using a crystallization solution containing sodium formate and PEG 3350 as precipitant, the heterodimer was cocrystallized with the promiscuous ligand 9-cis-retinoic acid (9C-RA) and a 13-residue fragment of the nuclear receptor interaction domain (NID) of the transcriptional coactivator TRAP220. The crystals grew in the trigonal space group P3(1)21, with unit-cell parameters a = b = 115.

Development of 99mTc labelled Lipiodol: biodistribution following injection into the hepatic artery of the healthy pig.

Background: We develop a method for the radiolabelling of Lipiodol with Tc, using a lipophilic complex, [99mTc-(S2CPh)(S3Ph)2], dissolved in Lipiodol (99mTc-SSS Lipiodol).

Results: The labelling yield is high (96 +/- 0.8%), and the radiochemical purity satisfactory (92 +/- 2.

A comparison of the National Ambulatory Medical Care Survey (NAMCS) measurement approach with direct observation of outpatient visits.

Background: The National Ambulatory Medical Care Survey (NAMCS) informs a wide range of important policy and clinical decisions by providing nationally representative data about outpatient practice. However, the validity of the NAMCS methods has not been compared with a reference standard.

Methods: Office visits of 549 patients visiting 30 family physicians in Northeastern Ohio were observed by trained research nurses.

Fitness costs of insecticide resistance in natural breeding sites of the mosquito Culex pipiens.

Genetic changes conferring adaptation to a new environment may induce a fitness cost in the previous environment. Although this prediction has been verified in laboratory conditions, few studies have tried to document this cost directly in natural populations. Here, we evaluated the pleiotropic effects of insecticide resistance on putative fitness components of the mosquito Culex pipiens.

Occurrence and linkage between secreted insecticidal toxins in natural isolates of Bacillus thuringiensis.

Little is known about the occurrence and linkage between secreted insecticidal virulence factors in natural populations of Bacillus thuringiensis (Bt). We carried out a survey of 392 Bt strains isolated from various samples originating from 31 countries. The toxicity profile of the culture supernatants of these strains was determined individually against Anthonomus grandis (Coleoptera) and Spodoptera littoralis (Lepidoptera).

Development and biodistribution of 188Re-SSS lipiodol following injection into the hepatic artery of healthy pigs.

Although intra-arterial radiotherapy with (131)I-labelled lipiodol is a useful therapeutic approach in the treatment of hepatocellular carcinomas, various disadvantages limit its use. Here we describe the development of (188)Re-SSS lipiodol, as well as its biodistribution in the healthy pig after injection into the hepatic artery. The (188)Re-SSS lipiodol was obtained after dissolving a chelating agent, previously labelled with (188)Re, in cold lipiodol.

Application of a specific and sensitive radiometric assay for microbial lipase activities in marine water samples from the lagoon of nouméa.

Marine microbiologists commonly assay lipase activities by using a synthetic fluorescent analog, 4-methylumbelliferyl (MUF)-oleate. The technique is convenient, but it is considered to be unspecific because of the structure of this analog. This study reports the design of a new specific and sensitive lipase assay based on the use of a radiolabeled triglyceride, [3H]triolein.