Tracking the flight and landing behaviour of western flower thrips in response to single and two-colour cues

Real-time 3D tracking and high-speed videography was used to examine the behaviour of a worldwide greenhouse pest, the western flower thrips (WFT), in response to different colours in the context of improving trap design. Measurements were taken of the number of landings on, and flight activity near, a lamp containing two LEDs of either the same colour or a combination of two colours presented side by side. Main findings show that landing patterns of WFT are different between colours, with landings on UV(+ red) as highly attractive stimulus being mostly distributed at the bottom half of the lamp, while for yellow also as very attractive and green as a 'neutral' stimulus, landings were clearly on the upper rim of the lamp. Additionally, a positive interaction with the UV-A(+ red) and yellow combination elicited the highest number of landings and flight time in front of the LED lamp. Conversely, a negative interaction was observed with decreased landings and flight time found for yellow when blue was present as the adjacent colour. Overall, differences between treatments were less obvious for flight times compared to number of landings, with tracking data suggesting that WFT might use different colours to orientate at different distances as they approach a visual stimulus.

Phenotypic characterization of the Hordeum bulbosum derived leaf rust resistance genes Rph22 and Rph26 in barley

Aims

Two introgression lines (ILs), 182Q20 and 200A12, which had chromosomal segments introgressed from Hordeum bulbosum in H. vulgare backgrounds, were identified to show seedling resistance against Puccinia hordei, possibly attributed to two resistance genes, Rph22 and Rph26, respectively. This study characterized the phenotypic responses of the two genes against P. hordei over different plant development stages.

Methods and Results

Using visual and fungal biomass assessments, responses of ILs 182Q20, 200A12 and four other barley cultivars against P. hordei were determined at seedling, tillering, stem elongation and booting stages. Plants carrying either Rph22 or Rph26 were found to confer gradually increasing resistance over the course of different development stages, with partial resistant phenotypes (i.e. prolonged rust latency periods, reduced uredinia numbers but with susceptible infection types) observed at seedling stage and adult plant resistance (APR) at booting stage. A definitive switch between the two types of resistance occurred at tillering stage.

Conclusions

Rph22 and Rph26 derived from H. bulbosum were well characterized and had typical APR phenotypes against P. hordei.

Significance and Impact of the Study

This study provides important insights on the effectiveness and expression of Rph22 and Rph26 against P. hordei during plant development and underpins future barley breeding programmes using non‐host as a genetic resource for leaf rust management.

Feeding Volatiles of Larval Sparganothis pilleriana (Lepidoptera: Tortricidae) Attract Heterospecific Adults of the European Grapevine Moth

Plants release volatiles in response to caterpillar feeding. These herbivore-induced plant volatiles (HIPVs) attract natural enemies of the herbivores and repel or attract conspecific adult herbivores in a tri-trophic interaction which has been considered to be an indirect plant defense against herbivores. Recently, we demonstrated the attraction of male and female European grapevine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae) to a blend of phenylacetonitrile and acetic acid, two compounds identified as HIPVs in heterospecific apple-leafroller interactions. The ecological basis of our findings is not clearly understood. Thus, this work was undertaken to investigate HIPVs in the grapevine-leafroller interaction and study the response of heterospecific adults L. botrana, to these volatiles. We collected headspace volatiles emitted from uninfested grapevines and grapevines infested with larvae of a generalist herbivore, the grapevine leafroller moth, Sparganothis pilleriana (Denis & Schiffermüller), and analyzed them using gas chromatography/mass spectrometry. Infested grape leaves released three compounds (phenylacetonitrile, indole, and 2-phenylethanol) not found from uninfested leaves. Nine different blends, comprising a full factorial set of the three compounds with each blend containing acetic acid, were tested in a field-cage trial. Only lures containing phenylacetonitrile caused a significant increase in trap catches compared to the other lures and blank traps. Electroantennographic tests show that L. botrana can detect the compounds. The results confirm our hypothesis that phenylacetonitrile is released during grapevines infestation with herbivores, and attracts adult L. botrana.

Liquid Baits with Oenococcus oeni Increase Captures of Drosophila suzukii

Simple Summary

Among the challenges arising from climate change and the transformation of agroecosystems is that agricultural production is heavily affected by invasive insect species. Invasive insects can establish in new areas where their development can progress due to a suitable climate and lack of natural enemies. Farmers have few options to mitigate those insects’ attacks. Current control tactics using pesticides must be replaced with more sustainable methods to counter invasive insect species. We approached the control of the invasive spotted-wing drosophila Drosophila suzukii, using a baiting system that manipulates insect behavior without use of toxic or non-sustainable chemicals. The results of our work are utilized for the monitoring and mass trapping of this devastating invasive species. In our innovative smart-design trap system, we use odors that attract flies and decrease damage in open field scenarios. Our trapping system can efficiently detect the first spring arrival of D. suzukii in agricultural fields and as a such, represents a good early monitoring tool. We conducted four years of laboratory and open-field trials in different berry crops. As a source of odor attraction, we used a mixture of wine, apple cider vinegar, and different commercially available strains of lactic acid bacteria.

Abstract

The spotted-wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), native to Eastern Asia, is an invasive alien species in Europe and the Americas, where it is a severe pest of horticultural crops, including soft fruits and wine grapes. The conventional approach to controlling infestations of SWD involves the use of insecticides, but the frequency of application for population management is undesirable. Consequently, alternative strategies are urgently needed. Effective and improved trapping is important as an early risk detection tool. This study aimed to improve Droskidrink^® (DD), a commercially available attractant for SWD. We focused on the chemical and behavioral effects of adding the bacterium Oenococcus oeni (Garvie) to DD and used a new trap design to enhance the effects of attractive lures. We demonstrate that microbial volatile compounds produced by O. oeni are responsible for the increase in the attractiveness of the bait and could be later utilized for the development of a better trapping system. Our results showed that the attractiveness of DD was increased up to two-fold by the addition of commercially available O. oeni when combined with an innovative trap design. The new trap-bait combination increased the number of male and especially female catches at low population densities.

Visually and olfactorily enhanced attractive devices for thrips management

'Lure-and-infect' is an insect pest management strategy with high potential but so far there are few examples of its application. Using traps as surrogates for auto-dissemination devices, we tested the attractiveness to naturally occurring thrips (Thysanoptera: Thripidae) of three trap types differing in colour and structure, with and without the thrips lure methyl isonicotinate (MI), and sticky plate traps as a control. The aim was to find more effective traps that could be further developed into devices for auto-dissemination and lure-and-infect of thrips. The number of thrips captured varied substantially with trap type and the presence of the MI lure. We found a high visual response to a sticky 'white ruffle' trap (i.e., a 30-cm-long cylindrical outline of folded fabric), compared to a commonly used blue sticky plate trap (Bug-scan) as the control. This effect was seen both in a greenhouse with roses (Rosa spp.), where we encountered western flower thrips, Frankliniella occidentalis (Pergande), and in a grass field, where we encountered onion thrips, Thrips tabaci Lindeman, and New Zealand flower thrips, Thrips obscuratus (Crawford). In the absence of MI, the white ruffle trap caught 7-22× more thrips than the control Bug-scan trap. A similarly designed blue ruffle trap and a modified Lynfield trap caught lower thrips numbers than the white ruffle and the control Bug-scan traps. Presence of MI substantially increased the captures of T. tabaci in all three trap types in the field (2.5-18×). In the greenhouse, without MI the white ruffle trap caught 3.5-14× more thrips than the Bug-scan, blue ruffle, or modified Lynfield traps. Presence of MI increased the captures of F. occidentalis males and females in the Lynfield and blue ruffle traps (1.4-2.8×), but not in the white ruffle trap in the greenhouse (ca. 1.1×). The importance of visual and olfactory factors for the design of effective auto-dissemination and lure-and-infect strategies for thrips management is discussed.

Selection of key floral scent compounds from fruit and vegetable crops by honey bees depends on sensory capacity and experience

Flowers have complex odours often comprising hundreds of volatile compounds. Floral scents are species-specific, and vary also among populations, varieties, sexes or lines, as well as with phenology. Honey bees, Apis mellifera, generally associate only a few key compounds among the complex floral scent with the food reward which guides their foraging choices. How these key compounds are selected remains partially unexplained, despite their crucial role in influencing foraging. Using electrophysiological techniques and behavioural assays, we identified the key bioactive compounds that bees detected with their antennae and that were associated with appetitive responses from four fruit crops and three vegetable crops. Three quantities of identified key volatile compounds were assayed with the two methods in each of four different seasons with experienced foragers. Whether the selection of these key compounds is determined by the sensory capability of the bee or influenced by its foraging experience was assessed by comparing experienced and naïve bees. Our results showed that experienced foragers were electrophysiologically-sensitive to a specific set of key compounds for each crop, independent of variation in quantity among several varieties. Experienced foragers responded to these compounds in all seasons, with increased electrophysiological amplitude with increasing quantities. Behavioural appetitive responses varied amongst compounds and seasons, revealing preferences based on associative learning. Naïve bees that were exposed to compounds and subsequently learned them, tended to be overall more sensitive. We discuss our results based on the identity of each bioactive compound and their presence in nature. Preferences for specific floral compounds based on sensory biases exist and associative learning may reinforce behavioural attraction depending on foraging experience in each season.

Host plant influences establishment and performance of Amblydromalus limonicus, a predator for Bactericera cockerelli

BACKGROUND

Management of tomato potato psyllid (TPP; Bactericera cockerelli (Šulc)) predominantly relies on insecticides. However, biological control agents (BCAs) could provide viable alternatives to suppress TPP populations. In this laboratory experiment, we assessed the predatory mite Amblydromalus limonicus (Garman & McGregor) as a BCA of TPP on whole plants of two tomato and two pepper cultivars over a 5-week period.

RESULTS

Plant species and cultivar had a significant effect on the ability of A. limonicus to suppress populations of TPP. Numbers of TPP were suppressed by A. limonicus on four pepper treatments, but on only one tomato treatment. Amblydromalus limonicus could survive and reproduce on pepper and tomato, but more were found on pepper at the end of the 5-week period.

CONCLUSION

Amblydromalus limonicus has the potential to suppress TPP populations on pepper but not tomato cultivars, based on the present study. Possible reasons for these results include the difference in leaf morphology between species, and higher predator:prey ratios on pepper than tomato because of the longer TPP generation time on pepper. © 2018 Society of Chemical Industry.

Genetic mapping of a barley leaf rust resistance gene Rph26 introgressed from Hordeum bulbosum

The quantitative barley leaf rust resistance gene, Rph26, was fine mapped within a H. bulbosum introgression on barley chromosome 1HL. This provides the tools for pyramiding with other resistance genes. A novel quantitative resistance gene, Rph26, effective against barley leaf rust (Puccinia hordei) was introgressed from Hordeum bulbosum into the barley (Hordeum vulgare) cultivar 'Emir'. The effect of Rph26 was to reduce the observed symptoms of leaf rust infection (uredinium number and infection type). In addition, this resistance also increased the fungal latency period and reduced the fungal biomass within infected leaves. The resulting introgression line 200A12, containing Rph26, was backcrossed to its barley parental cultivar 'Emir' to create an F₂ population focused on detecting interspecific recombination within the introgressed segment. A total of 1368 individuals from this F₂ population were genotyped with flanking markers at either end of the 1HL introgression, resulting in the identification of 19 genotypes, which had undergone interspecific recombination within the original introgression. F₃ seeds that were homozygous for the introgressions of reduced size were selected from each F₂ recombinant and were used for subsequent genotyping and phenotyping. Rph26 was genetically mapped to the proximal end of the introgressed segment located at the distal end of chromosome 1HL. Molecular markers closely linked to Rph26 were identified and will enable this disease resistance gene to be combined with other sources of quantitative resistance to maximize the effectiveness and durability of leaf rust resistance in barley breeding. Heterozygous genotypes containing a single copy of Rph26 had an intermediate phenotype when compared with the homozygous resistant and susceptible genotypes, indicating an incompletely dominant inheritance.

Multiple-Lure Surveillance Trapping for Ips Bark Beetles, Monochamus Longhorn Beetles, and Halyomorpha halys (Hemiptera: Pentatomidae)

Invasions by insects introduced via international trade continue to cause worldwide impacts. Surveillance programs using traps baited with host volatiles and pheromones can detect incursions of nonnative species. We report on two experiments executed to determine if attractants for several insect species can be combined without compromising trap catches and detection ability of target species. In the first experiment, we tested the effect of bark beetle pheromones (plus α-pinene) and trap contact with foliage on trap catches of the brown marmorated stink bug Halyomorpha halys Stål (Hemiptera: Pentatomidae) in traps baited with a mixture of bisabolenes and methyl (E,E,Z)-2,4,6-decatrienoate. Trap capture of H. halys adults was greater in traps not in contact with foliage, and the bark beetle pheromones ipsenol and ipsdienol did not affect trap capture of H. halys. In the second experiment, we tested the effects of multi-lure interactions among the primary host attractants α-pinene and ethanol, and the pheromones monochamol, ipsenol, ipsdienol, lanierone, and the H. halys compounds, on trap captures of various forest and agricultural insect pests. Specifically, we targeted Monochamus spp. (Coleoptera: Cerambycidae), Ips spp. (Coleoptera: Scolytinae) and H. halys. We found that a combination of all lures did not catch significantly lower numbers of Monochamus carolinensis Olivier, Monochamus scutellatus Say (Coleoptera: Cerambycidae), and Ips pini Say (Coleoptera: Scolytidae) than lure combinations missing components although removal of both lanierone and ipsdienol somewhat increased catches of Ips grandicollis Eichhoff (Coleoptera: Curculionidae). Our results support the use of traps baited with a full combination of these attractants in surveillance programs. This should reduce costs and increase detection rates of a wider range of conifer forest pests and H. halys.

Association mapping of starch chain length distribution and amylose content in pea (Pisum sativum L.) using carbohydrate metabolism candidate genes

BACKGROUND

Although starch consists of large macromolecules composed of glucose units linked by α-1,4-glycosidic linkages with α-1,6-glycosidic branchpoints, variation in starch structural and functional properties is found both within and between species. Interest in starch genetics is based on the importance of starch in food and industrial processes, with the potential of genetics to provide novel starches. The starch metabolic pathway is complex but has been characterized in diverse plant species, including pea.

RESULTS

To understand how allelic variation in the pea starch metabolic pathway affects starch structure and percent amylose, partial sequences of 25 candidate genes were characterized for polymorphisms using a panel of 92 diverse pea lines. Variation in the percent amylose composition of extracted seed starch and (amylopectin) chain length distribution, one measure of starch structure, were characterized for these lines. Association mapping was undertaken to identify polymorphisms associated with the variation in starch chain length distribution and percent amylose, using a mixed linear model that incorporated population structure and kinship. Associations were found for polymorphisms in seven candidate genes plus Mendel's r locus (which conditions the round versus wrinkled seed phenotype). The genes with associated polymorphisms are involved in the substrate supply, chain elongation and branching stages of the pea carbohydrate and starch metabolic pathways.

CONCLUSIONS

The association of polymorphisms in carbohydrate and starch metabolic genes with variation in amylopectin chain length distribution and percent amylose may help to guide manipulation of pea seed starch structural and functional properties through plant breeding.

Mobilization of horizontally acquired island 2 is induced in planta in the phytopathogen Pectobacterium atrosepticum SCRI1043 and involves the putative relaxase ECA0613 and quorum sensing

Integrative and conjugative elements (ICEs) contribute to the rapid evolution of bacterial pathogens via horizontal gene transfer of virulence determinants. ICEs have common mechanisms for transmission, yet the cues triggering this process under natural environmental or physiological conditions are largely unknown. In this study, mobilization of the putative ICE horizontally acquired island 2 (HAI2), present in the chromosome of the phytopathogen Pectobacterium atrosepticum SCRI1043, was examined during infection of the host plant potato. Under these conditions, mobilization of HAI2 increased markedly compared with in vitro cultures. In planta-induced mobilization of HAI2 was regulated by quorum sensing and involved the putative ICE-encoded relaxase ECA0613. Disruption of ECA0613 also reduced transcription of genes involved in production of coronafacic acid (Cfa), the major virulence factor harboured on HAI2, whereas their expression was unaffected in the quorum-sensing (expI) mutant. Thus, suppression of cfa gene expression was not regulated by the mobilization of the ICE per se, but was due directly to inactivation of the relaxase. The identification of genetic factors associated solely with in planta mobilization of an ICE demonstrates that this process is highly adapted to the natural environment of the bacterial host and can influence the expression of virulence determinants.

Marker assisted separation of resistance genes Rph22 and Rym16 (Hb) from an associated yield penalty in a barley: Hordeum bulbosum introgression line

The resistance genes Rph22 and Rym16 (Hb) transferred into barley from Hordeum bulbosum have been separated from a large yield penalty locus that was present in the original introgression line '182Q20'. The Hordeum bulbosum introgression line '182Q20' possesses resistance to barley leaf rust (Rph22) and Barley mild mosaic virus (Rym16 (Hb) ) located on chromosome 2HL. Unfortunately, this line also carries a considerable yield penalty compared with its barley genetic background 'Golden Promise'. Quantitative trait locus (QTL) mapping of the components of yield (total yield, thousand grain weight, hectolitre weight, percentage screenings and screened yield) was performed using 75 recombinant lines derived from the original '182Q20' introgression line. A QTL for the yield penalty was located in the proximal region of the introgressed segment. Marker assisted selection targeting intraspecific recombination events between overlapping H. bulbosum introgression segments was used to develop the lines '372E' and '372H' which feature genetically small introgressions around Rph22. Further yield trials validated the separation of both Rph22 and Rym16 (Hb) from the proximal yield penalty. These results, combined with molecular markers closely linked to Rph22 and Rym16 (Hb) , make these resistance genes more attractive for barley breeding.

Joint analysis of BICEP2/keck array and Planck Data

We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400  deg^{2} patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2  μK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150  GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r_{0.05}<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.

Starch phosphorylation in potato tubers is influenced by allelic variation in the genes encoding glucan water dikinase, starch branching enzymes I and II, and starch synthase III

Starch phosphorylation is an important aspect of plant metabolism due to its role in starch degradation. Moreover, the degree of phosphorylation of starch determines its physicochemical properties and is therefore relevant for industrial uses of starch. Currently, starch is chemically phosphorylated to increase viscosity and paste stability. Potato cultivars with elevated starch phosphorylation would make this process unnecessary, thereby bestowing economic and environmental benefits. Starch phosphorylation is a complex trait which has been previously shown by antisense gene repression to be influenced by a number of genes including those involved in starch synthesis and degradation. We have used an association mapping approach to discover genetic markers associated with the degree of starch phosphorylation. A diverse collection of 193 potato lines was grown in replicated field trials, and the levels of starch phosphorylation at the C6 and C3 positions of the glucosyl residues were determined by mass spectrometry of hydrolyzed starch from tubers. In addition, the potato lines were genotyped by amplicon sequencing and microsatellite analysis, focusing on candidate genes known to be involved in starch synthesis. As potato is an autotetraploid, genotyping included determination of allele dosage. Significant associations (p < 0.001) were found with SNPs in the glucan water dikinase (GWD), starch branching enzyme I (SBEI) and the starch synthase III (SSIII) genes, and with a SSR allele in the SBEII gene. SNPs in the GWD gene were associated with C6 phosphorylation, whereas polymorphisms in the SBEI and SBEII genes were associated with both C6 and C3 phosphorylation and the SNP in the SSIII gene was associated with C3 phosphorylation. These allelic variants have potential as genetic markers for starch phosphorylation in potato.

Measurement of the distribution of non-structural carbohydrate composition in onion populations by a high-throughput microplate enzymatic assay

BACKGROUND

Non-structural carbohydrate (NSC; glucose, fructose, sucrose and fructan) composition of onions (Allium cepa L.) varies widely and is a key determinant of market usage. To analyse the physiology and genetics of onion carbohydrate metabolism and to enable selective breeding, an inexpensive, reliable and practicable sugar assay is required to phenotype large numbers of samples.

RESULTS

A rapid, reliable and cost-effective microplate-based assay was developed for NSC analysis in onions and used to characterise variation in tissue hexose, sucrose and fructan content in open-pollinated breeding populations and in mapping populations developed from a wide onion cross. Sucrose measured in microplates employing maltase as a hydrolytic enzyme was in agreement with HPLC-PAD results. The method revealed significant variation in bulb fructan content within open-pollinated 'Pukekohe Longkeeper' breeding populations over a threefold range. Very wide segregation from 80 to 600 g kg(-1) in fructan content was observed in bulbs of F2 genetic mapping populations from the wide onion cross 'Nasik Red × CUDH2150'.

CONCLUSION

The microplate enzymatic assay is a reliable and practicable method for onion sugar analysis for genetics, breeding and food technology. Open-pollinated onion populations may harbour extensive within-population variability in carbohydrate content, which may be quantified and exploited using this method. The phenotypic data obtained from genetic mapping populations show that the method is well suited to detailed genetic and physiological analysis.

Communication disruption of Epiphyas postvittana (Lepidoptera: Tortricidae) by using two formulations at four point source densities in vineyards

Light brown apple moth [Epiphyas postvittana (Walker)] is now established as an economic and quarantine pest in California, and new technologies are being investigated to increase options for its management. Two new organic formulations for mating disruption, SPLAT LBAM HD-O and organic Hercon Biotie (biodegradable) were field tested at four point source densities (25, 72, 322, and 500/ha) and compared with the standard Isomate LBAM Plus (500/ha, as a positive control) and an untreated (negative) control. Assessment involved trapping using synthetic lures and virgin females. In total, 175,776 male light brown apple moths were caught to both the caged females and synthetic lures, from 10 February to 19 May 2011. The light brown apple moth catch dramatically decreased from baseline measurements after the treatments were applied, with the highest density treatments reducing catch to below 10% of the catch in the untreated controls within the first week (> 90% disruption). In synthetic lure traps, the SPLAT and Biotie treatment performed similarly well over all rates (P = 0.317 for posttreatment percentage communication disruption), but SPLAT performed better at disrupting virgin female traps (P = 0.045). There was a significant increase in disruption with an increasing number of points/ha (P < 0.001). Disruption of communication was similar for all three technologies (SPLAT, Biotie and Isomate) at 500 points/ha for both types of trap (P > 0.74). Disruption of this species in vineyards is thus highly feasible.

Inactivation of PbTopo IIIβ causes hyper-excision of the Pathogenicity Island HAI2 resulting in reduced virulence of Pectobacterium atrosepticum

Topoisomerase III enzymes are present only in a limited set of bacteria and their physiological role remains unclear. Here, we show that PbTopo IIIβ, a homologue of topoisomerase III encoded on the chromosome of Pectobacterium atrosepticum strain SCRI1043 (Pba SCRI1043), is involved in excision of HAI2, a discrete ~100 kb region, from the Pba SCRI1043 chromosome. HAI2 is a Pathogenicity Island (PAI) that encodes coronafacic acid (Cfa), a major virulence determinant required for infection of potato. PAIs are horizontally acquired genetic elements that in some instances are able to excise from the chromosome of their host cell to form a circular episome prior to transfer to a recipient bacterium. We demonstrate excision of HAI2 from the chromosome, a process that is independent of growth phase and that results in the production of a circular intermediate. Inactivation of PbTopo IIIβ causes a 10(3) - to 10(4) -fold increase in excision, leading to reduced fitness in vitro and a decrease in the virulence of Pba SCRI1043 on potato. These results suggest that PbTopo IIIβ is required for stable maintenance of HAI2 in the chromosome of Pba SCRI1043 and may control as yet unidentified genes involved in viability and virulence of Pba SCRI1043 on potato.

Predicting Take-All Severity in Second-Year Wheat Using Soil DNA Concentrations of Gaeumannomyces graminis var. tritici Determined with qPCR

The lack of accurate detection of Gaeumannomyces graminis var. tritici inoculum in soil has hampered efforts to predict the risk of severe take-all for wheat growers. The current study used a molecular method to quantify soil G. graminis var. tritici concentrations in commercial wheat fields in New Zealand and to compare them with the proportion of crops surpassing the thresholds for visible and moderate to severe take-all over three growing seasons. The study evaluated a soil G. graminis var. tritici DNA-based take-all prediction system developed in Australia, with four take-all risk categories. These categories were found to be useful for predicting disease severity in second wheat but did not clearly separate risk between fields in medium- and high-risk categories. A sigmoidal relationship was identified between inoculum concentration and the proportion of fields exceeding the two disease thresholds. A logistic response curve was used to further examine this relationship and evaluate the boundaries between take-all risk categories. G. graminis var. tritici boundaries between medium- and high-risk categories were clustered near or within the upper plateau of the relationship. Alternative G. graminis var. tritici boundaries for a three-category system were identified that provided better separation of take-all risk between categories. This information could improve prediction of the risk of severe take-all.

Radiation biology and inherited sterility of light brown apple moth (Lepidoptera: Tortricidae): developing a sterile insect release program

The radiation biology of two geographically isolated populations of the light brown apple moth [Epiphyas postvittana (Walker)] was studied in Australia and New Zealand as an initiation of a SIT/F1 sterility program. Pharate and < or = 2 d pre-emergence pupae were exposed to increasing radiation doses up to a maximum dose of 300 Gy. Fertility and other life history parameters were measured in emerging adults (parental) and their progeny (F1-F3 adults). Parental fecundity was significantly affected by increasing irradiation dose in pharate pupae only. For both populations, parental egg fertility declined with increasing radiation. This was most pronounced for the irradiated parental females whose fertility declined at a higher rate than of irradiated males. At 250 Gy, females < or = 2 d preemergence pupae produced few larvae and no adults at F1. No larvae hatched from 250 Gy-irradiated female pharate pupae. At 300 Gy, males still had residual fertility of 2-5.5%, with pharate pupae being the more radio-sensitive. Radiation-induced deleterious inherited effects in offspring from irradiated males were expressed as increased developmental time in F1 larvae, a reduction in percent F1 female survival, decreased adult emergence and increased cumulative mortality over subsequent generations. Males irradiated at > or = 150 Gy produced few but highly sterile offspring at F1 and mortality was > 99% by F2 egg.

Comparison of life history parameters of two Frankliniella occidentalis (Thysanoptera: Thripidae) strains in New Zealand

Two strains of western flower thrips, Frankliniella occidentalis (Pergande), are reputedly found in New Zealand. One strain was recorded in 1934, and it is most common in flowers of Lupinus arboreus outdoors (lupin strain); the other strain was first recorded in New Zealand in 1992 and is found mostly indoors on greenhouse crops (greenhouse strain). Laboratory studies were conducted to compare the life history parameters of these two strains. Thrips from each strain were fed sucrose solution and capsicum or lupin pollen and reared at 25 degrees C, >60% RH, and 16 L:8 D photoperiod. Significant differences in life history parameters were found. Preoviposition time was significantly shorter, and oviposition rate and fecundity were markedly higher (four-fold) for the greenhouse than for the lupin strain. The lupin strain performed significantly better on the capsicum pollen, laying more than twice as many eggs than on the lupin pollen over a 14-d period. The greenhouse strain development time from larvae to adult was marginally faster (0.7-1.1 d less) than the lupin strain because of a shorter prepupal and a marginally shorter pupal development time. Females of the greenhouse strain lived on average 69% longer than females from the lupin strain. Large differences in the intrinsic growth rate (r(m)) were found, with r(m) being 1.4-1.8 times higher for the greenhouse strain than the lupin strain, depending on pollen source. The results are discussed in relation to different ecological requirements and pest status of the two strains.

Pyridine compounds increase thrips (Thysanoptera: Thripidae) trap capture in an onion crop

The effect of the thrips (Thysanoptera: Thripidae) lures ethyl isonicotinate, methyl isonicotinate, and ethyl nicotinate on numbers of thrips captured in white water traps in an onion (Allium spp.) crop, in New Zealand, was examined. Female onion thrips, Thrips tabaci Lindeman (69.0%), and Thrips obscuratus Crawford (27.8%) (males and females) were the most common species found in traps in the onion crop. Ethyl isonicotinate, methyl isonicotinate, and ethyl nicotinate caught 18, 12, and 4x more onion thrips, respectively, than controls (no-lure). In contrast, traps with ethyl isonicotinate set up in a grass field at the same time as the onion crop trial caught 84x more onion thrips than traps without this lure. For T. obscuratus, traps with ethyl isonicotinate, methyl isonicotinate, and ethyl nicotinate caught 10, 13, and 12x more thrips, respectively, than controls in the onion crop.

4-Pyridyl carbonyl compounds as thrips lures: effectiveness for Western flower thrips in y-tube bioassays

In a search for chemical lures to manage the cosmopolitan crop pest western flower thrips (WFT), Frankliniella occidentalis, a Y-tube olfactometer was used to screen 20 compounds, including 18 4-pyridyl compounds. Comparison of Y-tube results for New Zealand flower thrips (NZFT), Thrips obscuratus, with field trapping data for ethyl nicotinate and ethyl isonicotinate, suggested that the minimum attractive dose (MAD) of an odor compound, where significantly ( p < 0.05) more than 50% of thrips walked up the odor-laden arm, provided a measure for selecting compounds to evaluate for potential lure efficacy in the field. Eighteen synthetic 4-pyridyl compounds were tested on female WFT in a Y-tube olfactometer and four 4-pyridyl carbonyl compounds had MADs lower than the known WFT attractants p-anisaldehyde (MAD 10 (-3) microL) and ethyl nicotinate (10 (-2) microL): methyl isonicotinate (10 (-6) microL), ethyl-2-chloropyridine-4-carboxylate (10 (-6) microL), ethyl isonicotinate (10 (-4) microL) and methyl 4-pyridyl ketone (10 (-5) microL). The suitability of MAD for selecting compounds for further evaluation of practical lure efficacy is discussed. Comparisons of activities within homologous series of esters and ketones showed that attractant activity decreased with chain length. 4-Formyl pyridine was an attractant at a dose of 10 (-5) microL, but was repellent at higher doses (10 (-2)-10 degrees microL).

Real-time quantitative PCR measurement of ileal Lactobacillus salivarius populations from broiler chickens to determine the influence of farming practices

A real-time quantitative PCR assay targeting a 16S-23S intergenic spacer region sequence was devised to measure the sizes of populations of Lactobacillus salivarius present in ileal digesta collected from broiler chickens. This species has been associated with deconjugation of bile salts in the small bowel and reduced broiler productivity. The assay was tested as a means of monitoring the sizes of L. salivarius populations from broilers fed diets with different compositions, maintained at different stocking densities, or given the antimicrobial drugs bacitracin and monensin in the feed. Stocking densities did not influence the numbers of L. salivarius cells in the ileum. A diet containing meat and bone meal reduced the size of the L. salivarius population relative to that of chickens given the control diet, as did administration of bacitracin and monensin in the feed. These changes in the target bacterial population were associated with improved broiler weight gain.

Use of quantitative real-time PCR to estimate maize endogenous DNA degradation after cooking and extrusion or in food products

Polymerase chain reaction (PCR) is being used increasingly to detect DNA sequences for food quality testing for GM content, microbial contamination, and ingredient content. However, food processing often results in DNA degradation and therefore may affect the suitability of PCR or even DNA sequence detection for food quality assurance. This paper describes a novel approach using quantitative real-time PCR (qPCR) to estimate the extent of DNA degradation. With use of two maize endogenous nuclear sequences, sets of four qPCR assays were developed to amplify target sequences ranging from<100 bp to approximately 1000 bp. The maize nuclear sequences used encode chloroplastic glyceraldehyde-3-phosphate dehydrogenase and cell wall invertase. The utility of the qPCR approach for quantifying the effective concentration of maize DNA that is needed to amplify variable length DNA sequences was demonstrated using samples of maize cornmeal cooked in water for variable times, extrusion products developed using different barrel temperature and torque settings, and a range of food products from supermarket shelves. Results showed that maize DNA was substantially degraded by a number of processing procedures, including cooking for 5 min or more, extrusion at high temperatures and/or high torque settings, and in most processed foods from supermarket shelves. Processing also reduced the effective concentration of DNA sequences capable of directing amplification of the <100 bp assays as well, particularly after popping of popping corn or extrusion at a combination of high temperature and torque settings. The approach for quantifying DNA degradation described in this paper may also be of use in disciplines where understanding the extent of DNA degradation is important, such as in environmental, forensic, or historical samples.

Starvation period and age affect the response of female Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) to odor and visual cues

The effects of starvation or age on the walking or flying response of female Frankliniella occidentalis to visual and/or odor cues in two types of olfactometer were examined in the laboratory. The response of walking thrips starved for 0, 1, 4, or 24h to an odor cue (1microl of 10% p-anisaldehyde) was examined in a Y-tube olfactometer. The take-off and landing response of thrips (unknown age) starved for 0, 1, 4, 24, 48 or 72h, or of thrips of different ages (2-3 days or 10-13 days post-adult emergence) starved for 24h, to a visual cue (98 cm(2) yellow sticky trap) and/or an odor cue (0.5 or 1.0 ml p-anisaldehyde) was examined in a wind tunnel. More thrips walked up the odor-laden arm in the Y-tube when starved for at least 4h (76%) than satiated thrips (58.7%) or those starved for 1h (62.7%, P<0.05). In the wind tunnel experiments the percentage of thrips to fly or land on the sticky trap increased between satiated thrips (7.3% to fly, 3.3% on trap) and those starved for 4h (81.2% to fly, 29% on trap) and decreased between thrips starved for 48 (74.5% to fly, 23% on trap) and 72 h (56.5% to fly, 15.5% on trap, P<0.05). Fewer younger thrips (38.8%) landed on a sticky trap containing a yellow visual cue of, those that flew, than older thrips (70.4%, P<0.05), although a similar percentage of thrips flew regardless of age or type of cue present in the wind tunnel (average 44%, P>0.05).

Identification of all chromosome arms and their involvement in meiotic homoeologous associations at metaphase I in 2 Hordeum vulgare L. x Hordeum bulbosum L. hybrids

We have identified all Hordeum bulbosum chromosomes in 2 diploid Hordeum vulgare x Hordeum bulbosum hybrids using suitable probes and fluorescence in situ hybridization. Using the parental idiograms allowed us to carry out a full analysis of chromosome associations among all chromosome arms in the hybrids. Association frequencies were generally lower for the short arms than for the long arms. There were also significant differences among the chromosome arms in association frequencies, partly correlated with the absolute length of the chromosome arm, as well as with the frequency of recombinant lines, which were recovered from partially fertile interspecific hybrids. The H. bulbosum idiogram will be useful for further chromosome association studies and will enable the identification of H. bulbosum chromosomes involved in chromosome addition or substitution lines.

Reduced metaphase I associations between the short arms of homologous chromosomes in a Hordeum vulgare L. x H. bulbosum L. diploid hybrid influences the frequency of recombinant progeny

Hordeum vulgare (cultivated barley) x H. bulbosum (bulbous barley grass) hybrids have been used to obtain disease-resistant recombinant lines (RLs). The RLs contain chromatin transferred from the wild species mostly onto the long arms of recipient barley chromosomes. To determine whether differences in meiotic metaphase I (MI) associations between the long and short arms of homologous chromosomes can account for the preponderance of introgressions on the long arms, we carried out fluorescent in situ hybridisation on MI chromosome preparations obtained from pollen mother cells of a diploid interspecific hybrid. By using various probes, we established that MI associations between the long arms occurred more frequently than between the short arms for the five chromosomes tested.

Quantification of progeny classes in two facultatively apomictic accessions of Hieracium

Hieracium is an established model system for studying the cytological and genetic basis of gametophytic apomixis. In common with most known apomicts, the formation of 'maternal seed' is not exclusive in Hieracium, as apomixis operates in conjunction with a low level of sexuality. When this occurs the form of apomixis is described as 'facultative'. The formation of maternal seed in these plants is characterised by the avoidance of meiosis followed by the parthenogenetic development of an unreduced egg cell. In some ovules, however, meiosis does proceed, and sometimes the fertilisation of an egg cell presages embryogenesis. As a result, this mechanism of facultative apomixis leads to the formation of several different types of progeny, each representing a unique combination of meiosis/apomeiosis and fertilisation/parthenogenesis. Furthermore, fertilisation may involve either self or non-self pollen, leading to the recognition of six progeny classes from each individual plant. To facilitate an understanding of these processes we have developed a method for identifying individuals from different progeny classes based on the inheritance of introduced heterologous marker genes. This technique permits the screening of many thousands of seedlings at germination, and the consequent isolation of individuals associated with rare classes. Progeny profiles were determined for two apomictic accessions of Hieracium. Both were found to develop approximately 2.5% of their seed from meiotically derived eggs under the experimental conditions used and to have a rate of hybridity of approximately 2%. Evidence was also found for the action of a self-incompatibility mechanism operating in these plants despite the autonomous nature of apomixis in Hieracinum. As a demonstration of the utility of this approach, a study was conducted of polyembryony in one accession. The results indicate that there was a 7 fold greater likelihood that a meiotically derived seedling would arise in a polyembryonic seed than in a single-embryo seed. This indicates that facultative apomixis in Hieracium not only results from the simultaneous occurrence of sexual and asexual seed formation in the same capitulum as previously demonstrated, but most often as parallel processes within the same ovule.

Ruptured ectopic pregnancy after elective termination of intrauterine pregnancy discovered by use of ultrasonography in the emergency department

The authors report a case of a 27-year-old female who was diagnosed as having a ruptured ectopic pregnancy approximately 12 hours after an elective termination of an intrauterine pregnancy (IUP) was performed. Multiple previous evaluations by an obstetrician for a chief complaint of abdominal pain revealed an IUP but did not disclose the underlying pathology. The ectopic pregnancy was identified by the emergency physician's use of ultrasound in the emergency department.

Electrocautery-ignited endotracheal tube fire: case report

The risk of fire in the airway associated with laser surgery is well known, but there are reports of endotracheal tube fires ignited by electrocautery, particularly during pharyngeal surgery or tracheostomy or both. This uncommon complication has potentially devastating consequences. Surgeons undertaking these procedures should be aware of this complication and be familiar with measures to avoid them. We present a case report of an electrocautery-ignited endotracheal tube fire during an elective tracheostomy, which resulted in the patient's death.

Effect of a comprehensive program to reduce needlestick injuries

The Arlington Hospital Needlestick Injury (NSI) Prevention Program was created to protect healthcare workers from NSI and to assess the effectiveness of our interventions. Interventions included revising NSI policy and procedures. The average NSI rate dropped from 109 to 43 per year after the interventions, over a period of 4 years.

Evaluation of the Vidas Chlamydia test to detect and verify Chlamydia trachomatis in urogenital specimens

The Vidas Chlamydia test (CHL) is an automated enzyme-linked immunofluorescence assay for the detection of Chlamydia trachomatis. Positive and equivocal results are confirmed with a blocking assay. A mouse monoclonal antibody directed against the chlamydial lipopolysaccharides was used for the test. The CHL assay is widely used in Europe, but U.S. experience with it is limited. Three clinical test sites (The Arlington Hospital, Arlington, Va., Indiana University, Indianapolis, and the University of California, San Francisco) compared CHL with tissue culture (TC) for the identification of chlamydia in urogenital specimens (2,453 females and 850 males). True positives (TP) were defined as either TC positive or TC negative and CHL positive by a positive direct fluorescent-antibody assay or PCR test. Overall prevalence was 5.5% for females, 10.3% for male urethral swabs, and 10.7% for combined male TC urethral swabs and CHL with first catch urine (FCU) specimens. Compared to TP, CHL and TC had sensitivities of 89.6 and 94.1% with female cervical swabs and 90.9 and 86.4% with male urethral swabs, respectively. CHL sensitivity was 81.2 for male FCU specimens and 77.7% for matching male TC swabs. There were relatively few false-positive results, with all specificities being >99.4%. With the blocking assay, Vidas CHL specificity was >99.7%. However, male FCU specimen sensitivity was compromised because 9.2% (7 of 76) of the TP were initially positive but were not confirmed. An improvement in the Vidas blocking assay is needed before we can recommend its use with male urine. Alternatively, one could argue that the specificity of the test is so high that a confirmatory assay is not needed. For male and female swabs, the Vidas CHL assay has a performance that is similar to that of TC.

Cellular immunity to cartilage aggrecan core protein in patients with rheumatoid arthritis and non-arthritic controls

OBJECTIVE

To identify antigen(s) among purified deglycosylated aggrecan peptides spanning the chondroitin sulphate domain that may be responsible for the initiation or perpetuation of the autoimmune responses in rheumatoid arthritis (RA).

METHODS

Aggrecan was purified from human articular cartilage and deglycosylated with either bacterial glycosidases or trifluoromethanesulphonic acid (TFMS). Twelve overlapping peptides (15 residues) spanning the chondroitin sulphate domain with N-terminal residues offset by three amino acids were synthesised. T cell responses to these antigens in RA patients and age matched controls were assessed in vitro by antigen specific T cell proliferation assays.

RESULTS

Enzymically deglycosylated aggrecan (EDA) stimulated proliferation of T cells isolated from the peripheral blood in a greater proportion of patients with RA than controls. In a subset (12.5%) of RA patients, the magnitude of stimulation lay outside the control range. T cell proliferative responses to TFMS treated aggrecan were greater than, but well correlated with, responses to EDA. T cells from 15 patients were also stimulated with the pooled synthetic peptides. Four of seven patients who demonstrated T cell reactivity to EDA (seven of 15) also showed enhanced T cell proliferation to synthetic peptides.

CONCLUSION

These data suggest that an autoantigenic T cell epitope may lie within the chondroitin sulphate domain of aggrecan.

Use of 0.3% triclosan (Bacti-Stat) to eradicate an outbreak of methicillin-resistant Staphylococcus aureus in a neonatal nursery

BACKGROUND

Once established in an institution, methicillin-resistant Staphylococcus aureus (MRSA) outbreaks have proved difficult to eradicate, despite intensive infection control measures. This report describes the nosocomial infection with MRSA of 22 male infants in a neonatal nursery during a 7-month period and the infection control procedures that effectively brought this outbreak under control and eliminated recurrence for more than 3 1/2 years.

METHODS

After a single index case of bullous impetigo caused by MRSA in a neonate discharged from the nursery 2 weeks previously, an additional 18 cases of MRSA skin infections were clustered in a 7-week period. Aggressive infection control measures were instituted, including changes in umbilical cord care, circumcision procedures, diapers, handwashing, gloves, gowns, linens, disinfection, placement in cohorts of neonates and staff, surveillance, and monitoring.

RESULTS

These measures were not effective in slowing the outbreak. The single additional measure of changing handwashing and bathing soap to a preparation containing 0.3% triclosan (Bacti-Stat) was associated with the immediate termination of the acute phase of the MRSA outbreak.

CONCLUSION

The nursery has remained free of MRSA for more than 3 1/2 years, attesting to the success of our program.

Resistance of cowpea [Vigna unguiculata (L.) Walp.] to Striga gesnerioides (Willd.) Vatke, a parasitic angiosperm

An in vitro growth system was used to investigate the expression of resistance of cowpea [Vigna unguiculata (L.) Walp.] varieties B301 and 58-57 to the angiosperm parasite Striga gesnerioides (Willd.) Vatke. Variety Blackeye was included in experiments as a susceptible control. Seeds of S. gesnerioides germinated on the roots of all varieties. Two different mechanisms of resistance were expressed in B301 and 58-57 after penetration of host roots by parasite radicles. The first mechanism was expressed in both varieties; host tissue around invading Striga radicles became necrotic in association with the early death of the parasite and lack of tubercle formation. On variety 58-57, the necrosis response was expressed only when the roots were inoculated with Striga from Burkina Faso but Striga from Mali successfully parasitized the roots of variety 58-57. The second mechanism was observed only on variety B301. Striga radicles infected cowpea roots, tubercles were formed but remained at 1-2 mm in diameter with very limited stem growth. No further development of the parasite occurred in vitro or when infected cowpeas were grown in soil or vermiculite. Similarities between the expression of resistance of cowpea to Striga and ot plants to plant pathogenic fungi are discussed.

Dosage effects of pulsed steroid therapy on serum cortisol levels in oral and maxillofacial surgery patients

The purpose of this study was to determine the effects of two dosage regimens of dexamethasone on the serum cortisol levels of a group of patients undergoing major maxillofacial surgical procedures. Analysis of the data demonstrated that the use of dexamethasone, 10 to 20 mg intravenously given every 3 hours intraoperatively and every 4 hours postoperatively over 24 hours, followed by a repository dose of 80 mg of intramuscular methylprednisolone, causes short-term serum cortisol suppression. The maximum depression occurred on postoperative day 3; normal levels were restored by postoperative day 7. Therefore, pulsed therapy can be considered relatively safe when known contraindications have been considered.