Field Evaluation of Insecticides for Control of Cabbage Maggot (Diptera: Anthomyiidae) in Rutabaga in Canada.

At the time of this research, there were only two insecticides registered for control of cabbage maggot, Delia radicum L., in rutabaga in Canada, one of which (diazinon) will be deregistered by 2017, and resistance having been reported in some areas for the other (chlorpyrifos). To screen for chemistries to replace these organophosphates, and obtain efficacy data comparable between key vegetable brassica production areas in Canada, four small plot field studies were conducted concurrently in British Columbia, Saskatchewan, Ontario, and Quebec in 2009. These studies followed standardized protocols for seeding, application of insecticide drenches, sampling and damage assessment, and generally tested the same products. Of the insecticides evaluated, none provided maggot control comparable with the industry standard, chlorpyrifos. However, cyantraniliprole (Cyazypyr 200SC; registered in 2015 as Verimark) applied at 3 g AI (15.0 ml product)/100 m row of seeded rutabagas consistently provided the next highest reduction in % culls, suggesting the efficacy of this chemical may be improved if used at higher rates. The results of these studies are discussed in the context of current literature on D. radicum management in rutabaga. Future management strategies are also discussed, including a transplant plug treatment approach for increasing the dosage per plant and efficacy of chemistries such as Cyazypyr 200SC in the field.

Transitional sublethal and lethal effects of insecticides after dermal exposures to five economic species of wireworms (Coleoptera: Elateridae).

During an insecticide toxicity study involving field-collected dusky wireworm, Agriotes obscurus (L.) (Coleoptera: Elateridae), wireworms exposed dermally to six classes of insecticides exhibited characteristic transitional symptoms of toxicity. These symptoms, collectively termed "morbidity," were categorized as "writhing," "leg and mouthpart movements," or "mouthpart-only body movements." These symptoms could persist for long periods, depending on insecticide and dose, with morbid wireworms ultimately recovering or dying. Additional LC50 and LD50 toxicity studies showed that these stages of morbidity also occurred in four other wireworm species, notably Agriotes sputator (L.), Limonius canus LeConte, Ctenicera pruinina (Horn), and Ctenicera destructor (Brown). In addition, all species exposed dermally to clothianidin moved in significant numbers to the surface of soil in posttreatment holding cups. This movement was not observed when these species were exposed to chlorpyrifos or the control solvent. These findings suggest that toxicity trials involving wireworms should include observations on morbidity, and the duration of trials should continue until symptoms of morbidity cease. The long-term morbidity and potential recovery or death of wireworms exposed to certain insecticides has implications for how laboratory and field studies can be better designed and interpreted in the future.

Mortality of a wireworm, Agriotes obscurus (Coleoptera: Elateridae), after topical application of various insecticides.

Ten insecticides representing seven chemical groups were applied at various concentrations topically by using a Potter Spray Tower to evaluate their relative toxicities on the European wireworm Agriotes obscurus L. (Coleoptera: Elateridae). Wireworms were stored at 15 degrees C after exposure to organophosphate (OP) (chlorpyrifos, diazinon), pyrethroid (tefluthrin), thianicotinoid (thiamethoxam, clothianidin), chloronicotinoid (imidacloprid, acetamiprid), phenyl pyrazole (fipronil), organochlorine (lindane), and spinosyn (spinosad) insecticides, and their postapplication health was evaluated weekly for up to 301 d. LC50, LC90, LT50, and LT90 values were calculated for each chemical except acetamiprid, and compared with those of lindane, clothianidin, and chlorpyrifos. Wireworms exposed to OPs died or recovered more quickly (LT50 < 20 d, LT90 < 50 d), than those exposed to all other insecticides tested except tefluthrin (LT50 = 25.5 d, LT90 = 66.5 d). Wireworms exposed to sublethal concentrations of all neonicotinoids quickly became moribund after application but made a full recovery. Wireworms exposed to fipronil at concentrations near the LC90 value showed no intoxication symptoms for up to 35 d, and they did not recover after symptoms developed. For each chemical, increasing the concentration increased the time required for wireworms to recover but decreased the time required to kill wireworms. Fipronil was highly toxic to wireworms (LC50 = 0.0001%), but acetamiprid (LC50 = 1.82%), imidacloprid (LC50 = 0.83%), tefluthrin (LC50 = 0.23%), diazinon (LC50 = 0.54%), and spinosad (LC50 = 0.51%) were not. The toxicity of both clothianidin (LC50 = 0.07%) and thiamethoxam (LC50 = 0.17%) were similar to those oflindane (LC50 = 0.06%) and chlorpyrifos (LC50 = 0.10%).

Evaluation of sampling methodology for determining the population dynamics of onion thrips (Thysanoptera: Thripidae) in Ontario onion fields.

Onion thrips, Thrips tabaci Lindeman, are an economic pest of alliums worldwide. In Ontario onion-growing regions, seasonal abundance and population trends of onion thrips are not well known. The objectives of this research were to investigate onion thrips population dynamics by using both white sticky traps and plant counts, to gain insight into flight height, and to determine the genus and sex of thrips fauna present in monitored fields. Adult thrips were captured on white sticky traps placed in two commercial onion fields in the Thedford-Grand Bend Marsh region as early as mid-May in 2001, 2002, and 2003. Thrips were not recorded on onion plants in these fields until late June and early July. A comparison of sticky trap captures to plant counts revealed a strong, positive correlation, indicating that sticky traps, which consistently detected thrips earlier than plant counts, could be used instead of plant counts early in the season to monitor onion thrips populations. Pole traps placed in onion and an adjacent soybean, Glycine max (L.) Merr., field revealed that regardless of crop type, most thrips were captured 0.7-0.95 m above the soil surface. During this study, 70% of 137,000 thrips captured on sticky traps and 89% of 1,482 thrips captured in pan traps were female onion thrips. No male onion thrips were identified in this study: most of the remaining thrips were Frankliniella spp.

A pilot evaluation of tibia lead concentrations in Taiwan.

BACKGROUND: The aims of this study were to examine some of the factors that influence tibia lead concentrations, tibia lead x-ray fluorescence measurement uncertainty and blood lead concentrations, and to compare tibia lead concentrations in Taiwanese lead workers to those observed in lead workers from other countries. METHODS: A pilot evaluation of 43 adult lead workers who underwent measurements of tibia lead and blood lead concentrations. RESULTS: Mean and maximum tibia lead concentrations were 54 microg of Pb per g of bone mineral(microg/g) and 193 microg/g, respectively. Mean and maximum blood lead concentrations were 44 microg/dl and 92 microg/dl, respectively. CONCLUSION: Past occupational control of lead exposure in Taiwan, ROC, did not prevent these workers from accumulating tibia lead concentrations greater than those in similar workers elsewhere in the world.

Structural and dynamic analysis of residual dipolar coupling data for proteins.

The measurement of residual dipolar couplings in weakly aligned proteins can potentially provide unique information on their structure and dynamics in the solution state. The challenge is to extract the information of interest from the measurements, which normally reflect a convolution of the structural and dynamic properties. We discuss here a formalism which allows a first order separation of their effects, and thus, a simultaneous extraction of structural and motional parameters from residual dipolar coupling data. We introduce some terminology, namely a generalized degree of order, which is necessary for a meaningful discussion of the effects of motion on residual dipolar coupling measurements. We also illustrate this new methodology using an extensive set of residual dipolar coupling measurements made on (15)N,(13)C-labeled human ubiquitin solvated in a dilute bicelle solution. Our results support a solution structure of ubiquitin which on average agrees well with the X-ray structure (Vijay-Kumar, et al., J. Mol. Biol. 1987, 194, 531--544) for the protein core. However, the data are also consistent with a dynamic model of ubiquitin, exhibiting variable amplitudes, and anisotropy, of internal motions. This work suggests the possibility of primary use of residual dipolar couplings in characterizing both structure and anisotropic internal motions of proteins in the solution state.

Cross-correlated chemical shift modulation: a signature of slow internal motions in proteins.

A novel NMR experiment allows one to characterize slow motion in macromolecules. The method exploits the fact that motions, such as rotation about dihedral angles, induce correlated fluctuations of the isotropic chemical shifts of the nuclei in the vicinity. The relaxation of two-spin coherences involving C(alpha) and Cbeta nuclei in proteins provides information about correlated fluctuations of the isotropic chemical shifts of C(alpha) and Cbeta. The difference between the relaxation rates of double- and zero-quantum coherences and is shown to be affected by cross-correlated chemical shift modulation. In ubiquitin, evidence for slow motion is found in loops or near the ends of beta-strands and alpha-helices.

Dipolar couplings as a probe of molecular dynamics and structure in solution.

The introduction of residual dipolar coupling methodology has increased the scope of structural biological problems that can be addressed by NMR spectroscopy. Conformational changes, the relative orientation of domains, and intermolecular complexes can now be characterized accurately and rapidly using NMR. The development of residual dipolar coupling methodology for the rapid recognition of homologous protein folds and for studies of submillisecond timescale dynamics has also seen considerable progress.

Discovery of a potent, orally bioavailable beta(3) adrenergic receptor agonist, (R)-N-[4-[2-[[2-hydroxy-2-(3-pyridinyl)ethyl]amino]ethyl]phenyl]-4-[4 -[4-(trifluoromethyl)phenyl]thiazol-2-yl]benzenesulfonamide.

As part of our investigation into the development of orally bioavailable beta(3) adrenergic receptor agonists, we have identified a series of pyridylethanolamine analogues possessing a substituted thiazole benzenesulfonamide pharmacophore that are potent human beta(3) agonists with excellent selectivity against other human beta receptor subtypes. Several of these compounds also exhibited an improved pharmacokinetic profile in dogs. For example, thiazole sulfonamide 2e (R = 4-F(3)C-C(6)H(4)) is a potent full beta(3) agonist (EC(50) = 3.6 nM, 94% activation) with >600-fold selectivity over the human beta(1) and beta(2) receptors, which also displays good oral bioavailability in several mammalian species, as well as an extended duration of action.

Estimation of diaphragm length in patients with severe chronic obstructive pulmonary disease.

In patients with advanced chronic obstructive pulmonary disease (COPD) diaphragm function may be compromised because of reduced muscle fibre length. Diaphragm length (L(Di)) can be estimated from measurements of transverse diameter of the rib cage (D(Rc)) and the length of the zone of apposition (L(Zapp)) in healthy subjects, but this method has not been validated in patients with COPD. Postero-anterior chest radiographs were obtained at total lung capacity (TLC), functional residual capacity (FRC) and residual volume (RV) in nine male patients with severe COPD (mean [S.D.]; FEV(1), 23 [6] %pred.; FRC, 199 [15] %pred.). Radiographs taken at TLC were used to identify the lateral costal insertions of the diaphragm (L(Zapp) assumed to approach zero at TLC). L(Di) was measured directly and also estimated from measurements of L(Zapp) and D(Rc) using a prediction equation derived from healthy subjects. The estimation of L(Di) was highly accurate with an intraclass correlation coefficient of 0.93 and 95% CI of approximately +/-8% of the true value. L(Di) decreased from 426 (64) mm at RV to 305 (31) mm at TLC. As there were only small and variable changes in D(Rc) across the lung volume range, most of the L(Di) changes occurred in the zone of apposition. Additional studies showed that measurements of L(Di) from PA and lateral radiographs performed at different lung volumes were tightly correlated. These results suggest that non-invasive measurements of L(Zapp) in the coronal plane (e.g. using ultrasonography) and D(Rc) (e.g. using magnetometers) can be used to provide an accurate estimate of L(Di) in COPD patients.

Potent, selective 3-pyridylethanolamine beta3 adrenergic receptor agonists possessing a thiazole benzenesulfonamide pharmacophore.

A series of thiazole benzenesulfonamide-substituted 3-pyridylethanolamines was prepared and evaluated for their human beta3 adrenergic receptor agonist activity. Incorporation of aryl and heteroaryl substitution in the 4-position of the thiazole ring resulted in a number of highly potent and selective beta3 agonists. Results of preliminary in vivo evaluation of several of these compounds is described.

Orienting domains in proteins using dipolar couplings measured by liquid-state NMR: differences in solution and crystal forms of maltodextrin binding protein loaded with beta-cyclodextrin.

Protein function is often regulated by conformational changes that occur in response to ligand binding or covalent modification such as phosphorylation. In many multidomain proteins these conformational changes involve reorientation of domains within the protein. Although X-ray crystallography can be used to determine the relative orientation of domains, the crystal-state conformation can reflect the effect of crystal packing forces and therefore may differ from the physiologically relevant form existing in solution. Here we demonstrate that the solution-state conformation of a multidomain protein can be obtained from its X-ray structure using an extensive set of dipolar couplings measured by triple-resonance multidimensional NMR spectroscopy in weakly aligning solvent. The solution-state conformation of the 370-residue maltodextrin-binding protein (MBP) loaded with beta-cyclodextrin has been determined on the basis of one-bond (15)N-H(N), (15)N-(13)C', (13)C(alpha)-(13)C', two-bond (13)C'-H(N), and three-bond (13)C(alpha)-H(N) dipolar couplings measured for 280, 262, 276, 262, and 276 residues, respectively. This conformation was generated by applying hinge rotations to various X-ray structures of MBP seeking to minimize the difference between the experimentally measured and calculated dipolar couplings. Consistent structures have been derived in this manner starting from four different crystal forms of MBP. The analysis has revealed substantial differences between the resulting solution-state conformation and its crystal-state counterpart (Protein Data Bank accession code 1DMB) with the solution structure characterized by an 11(+/-1) degrees domain closure. We have demonstrated that the precision achieved in these analyses is most likely limited by small uncertainties in the intradomain structure of the protein (ca 5 degrees uncertainty in orientation of internuclear vectors within domains). In addition, potential effects of interdomain motion have been considered using a number of different models and it was found that the structures derived on the basis of dipolar couplings accurately represent the effective average conformation of the protein.

Oxidative stress increases ubiquitin--protein conjugates in synaptosomes.

Synaptosomes were incubated in the presence of FeSO4 to test the hypothesis that iron-catalyzed oxidative damage causes an increase in the ubiquitination of synaptosomal proteins. Incubation with 10 or 50 microM FeSO4 caused concentration-dependent increases in carbonyl groups (an indication of protein oxidation) and ubiquitinated proteins (determined by probing Western blots with a monoclonal antibody to ubiquitin). Differences in protein ubiquitination occurred within 5 min of incubation, indicating a rapid response to oxidative stress. Results of experiments with MG-132, an inhibitor of the degradation of ubiquitinated proteins, suggested that oxidative damage stimulated ubiquitination rather than inhibited degradation of ubiquitinated proteins. The data are consistent with the hypothesis that synaptic terminals utilize the ubiquitin/proteasome proteolytic pathway to degrade oxidatively damaged proteins.

An HNCO-based Pulse Scheme for the Measurement of 13Cα-1Hα One-bond Dipolar couplings in 15N, 13C Labeled Proteins.

A triple resonance pulse scheme is presented for recording 13Cα-1Hα one-bond dipolar couplings in 15N, 13C labeled proteins. HNCO correlation maps are generated where the carbonyl chemical shift is modulated by the 13Cα-1Hα coupling, with the two doublet components separated into individual data sets. The experiment makes use of recently described methodology whereby the protein of interest is dissolved in a dilute solution of bicelles which orient above a critical temperature, thus permitting measurement of significant couplings (Tjandra and Bax, 1997a). An application to the protein ubiquitin is described.

NMR evidence for slow collective motions in cyanometmyoglobin.

Residual dipolar couplings observed in NMR spectra at very high magnetic fields have been measured to a high degree of accuracy for the paramagnetic protein cyanometmyoglobin. Deviations of these measurements from predictions based on available crystallographic and solution structures are largely systematic and well correlated within a given helix of this highly alpha-helical protein. These observations can be explained by invoking collective motion and small displacements of representative helices from their reported average positions in the solid state. Thus, the measurements appear to be capable of providing important insights into slower, collective protein motions, which are likely to be important for function, and which have been difficult to study using established experimental techniques.

A quantitative J-correlation experiment for the accurate measurement of one-bond amide 15N-1H couplings in proteins.

Very precise measurements of 1JNH couplings have been made for approximately 40% of the amide sites in cyanometmyoglobin using two different experimental approaches. The first approach is a previously described frequency-based method in which the couplings are observed as splittings in the frequency-domain spectrum. The second is a new approach, along the lines of quantitative J-correlation spectroscopy, in which the coupling is encoded in the resonance intensity. Measurements obtained from the two experimental techniques are in agreement to a high degree of precision (s.d. of 0.17 Hz) and residual deviations appear to be largely random. The new method offers substantial time savings when resonances are widely dispersed in the frequency domain and may offer improved precision in these instances.

Nuclear magnetic dipole interactions in field-oriented proteins: information for structure determination in solution.

The measurement of dipolar contributions to the splitting of 15N resonances of 1H-15N amide pairs in multidimensional high-field NMR spectra of field-oriented cyanometmyoglobin is reported. The splittings appear as small field-dependent perturbations of normal scalar couplings. Assignment of more than 90 resonances to specific sequential sites in the protein allows correlation of the dipolar contributions with predictions based on the known susceptibility and known structure of the protein. Implications as an additional source of information for protein structure determination in solution are discussed.