Occurrence, ecology and potential impact of the New Zealand wheat bug Nysius huttoni White (Hemiptera: Lygaeidae) in Belgium

In 2002 the New Zealand wheat bug Nysius huttoni White was observed for the first time in the Netherlands and Belgium. The introduction of N. huttoni to our regions presumably occurred via overseas transport of apple and kiwi fruits from New Zealand. Laboratory experiments showed that both eggs and adults of N. huttoni were capable of surviving cold conditions similar to those in overseas transportation. Specimens were sampled in Belgium and the Netherlands, and a DNA sequence analysis indicated a 100% similarity with N. huttoni material collected in Christchurch, New Zealand. The distribution of the lygaeid in Belgium in 2008 was studied based on a systematic sampling at 105 locations. The bug had been able to spread over most of the Belgian territory, with the exception of the most southern and eastern provinces. Given the poor flight capacity of Belgian N. huttoni populations, other methods of dispersal may be involved. N. huttoni occurred primarily in ruderal habitats, and its weedy host plants belong to very common plant families. Several observations support N. huttoni not being a threat for agricultural crops in Belgium under the present conditions of climate and soil usage

Engineered flock house virus for targeted gene suppression through RNAi in fruit flies (Drosophila melanogaster) in vitro and in vivo

RNA interference (RNAi) is a powerful tool to study functional genomics in insects and the potential of using RNAi to suppress crop pests has made outstanding progress. However, the delivery of dsRNA is a challenging step in the development of RNAi bioassays. In this study, we investigated the ability of engineered Flock House virus (FHV) to induce targeted gene suppression through RNAi under in vitro and in vivo condition. As proxy for fruit flies of agricultural importance, we worked with S2 cells as derived from Drosophila melanogaster embryos, and with adult stages of D. melanogaster. We found that the expression level for all of the targeted genes were reduced by more than 70% in both the in vitro and in vivo bioassays. Furthermore, the cell viability and median survival time bioassays demonstrated that the recombinant FHV expressing target gene sequences caused a significantly higher mortality (60-73% and 100%) than the wild type virus (24 and 71%), in both S2 cells and adult insects, respectively. This is the first report showing that a single stranded RNA insect virus such as FHV, can be engineered as an effective in vitro and in vivo RNAi delivery system. Since FHV infects many insect species, the described method could be exploited to improve the efficiency of dsRNA delivery for RNAi-related studies in both FHV susceptible insect cell lines and live insects that are recalcitrant to the uptake of naked dsRNA

Engineered Flock House Virus for Targeted Gene Suppression Through RNAi in Fruit Flies (Drosophila melanogaster) in Vitro and in Vivo

RNA interference (RNAi) is a powerful tool to study functional genomics in insects and the potential of using RNAi to suppress crop pests has made outstanding progress. However, the delivery of dsRNA is a challenging step in the development of RNAi bioassays. In this study, we investigated the ability of engineered Flock House virus (FHV) to induce targeted gene suppression through RNAi under in vitro and in vivo condition. As proxy for fruit flies of agricultural importance, we worked with S2 cells as derived from Drosophila melanogaster embryos, and with adult stages of D. melanogaster. We found that the expression level for all of the targeted genes were reduced by more than 70% in both the in vitro and in vivo bioassays. Furthermore, the cell viability and median survival time bioassays demonstrated that the recombinant FHV expressing target gene sequences caused a significantly higher mortality (60–73% and 100%) than the wild type virus (24 and 71%), in both S2 cells and adult insects, respectively. This is the first report showing that a single stranded RNA insect virus such as FHV, can be engineered as an effective in vitro and in vivo RNAi delivery system. Since FHV infects many insect species, the described method could be exploited to improve the efficiency of dsRNA delivery for RNAi-related studies in both FHV susceptible insect cell lines and live insects that are recalcitrant to the uptake of naked dsRNA

Therapeutic effects of dietary intervention on neuroinflammation and brain metabolism in a rat model of photothrombotic stroke

INTRODUCTION: A possible target for stroke management is modulation of neuroinflammation. Evidence suggests that food components may exert anti-inflammatory properties and thus may reduce stroke-induced brain damage. AIM: To investigate the efficacy of a diet, containing anti-inflammatory ingredients, as treatment for focal ischemic brain damage induced by photothrombotic stroke in the somatosensory cortex of rats. RESULTS: Brain lesions were surrounded by strong astrogliosis on both day 7 and day 21 after stroke and were accompanied by a trend toward globally decreased glucose metabolism on day 7. The investigational diet applied 2 weeks before the ischemia did not affect astrocyte activation on day 7, but reduced it at day 21. The investigational diet applied immediately after the ischemia, increased astrocyte activation on day 7 and completely reversed this effect on day 21. Moreover, postischemic intervention increased glucose metabolism in somatosensory cortex ipsilateral to the lesion on day 7. CONCLUSION: This study reveals potentially beneficial effects of a diet containing elevated amounts of anti-inflammatory nutrients on the recovery from ischemic brain damage. Therefore, dietary intervention can be considered as an adjuvant therapy for recovery from this brain pathology

Oral RNAi to control Drosophila suzukii: laboratory testing against larval and adult stages

The spotted wing Drosophila (Drosophila suzukii) is an invasive and serious economic pest to small and stone fruits and its control is difficult. RNA interference (RNAi) or double-stranded RNA (dsRNA)-mediated gene silencing is rapidly becoming a widely used functional genomics tool in insects and holds great potential for insect pest control. This study investigates whether RNAi is functional in D. suzukii and whether oral delivery of dsRNA can elicit gene silencing and insecticidal activity. Firstly, microinjection of dsRNA targeting two essential genes (alpha COP and shrb) into the haemolymph of adult flies was performed, confirming that the RNAi system is functional and that gene silencing results in mortality. Secondly, dsRNA targeting alpha-COP and two extra essential genes, rpl13 and vha26, was mixed with artificial diet and fed to the larval and adult stages of D. suzukii. With naked dsRNA, no clear silencing and mortality were scored. However, combining dsRNA with a transfection reagent led to a significant increase in gene silencing and insect mortality. The best results were obtained with ds-Vha26. The results are discussed in relation to future optimization of the production, formulation, combinations and delivery of dsRNA

Effect of starvation on the cold tolerance of adult Drosophila suzukii (Diptera: Drosophilidae)

International audienceThe spotted wing drosophila, Drosophila suzukii , is an invasive pest in Europe and North America. Access to resources may be challenging in late fall, winter and early spring and flies may suffer from food deprivation along with cold stress in these periods. Whereas a plethora of studies have been performed on the overwintering capacity of D. suzukii , the effects of starvation on the fly's cold tolerance have not been addressed. In the present study, young D. suzukii adults (reared at 25°C, LD 12:12 h) were deprived of food for various periods (0, 12, 24 and 36 h), after which chill coma recovery time, critical thermal minimum, as well as acute and chronic cold tolerance were assessed. Additionally, the body composition of adults (body mass, water content, total lipid, glycerol, triglycerides, glucose and proteins) before and after starvation periods was analysed to confirm that starvation had detectable effects. Starved adults had a lower body mass, and both lipid and carbohydrate levels decreased with starvation time. Starvation slightly increased critical thermal minimum and affected chill coma recovery time; however, these changes were not gradual with starvation duration. Starvation promoted acute cold tolerance in both sexes. This effect appeared faster in males than in females. Food deprivation also led to enhanced survival to chronic cold stress. Short-term starvation was thus associated with significant changes in body composition in D. suzukii , and these alterations could alter some ecologically relevant traits related to cold tolerance, particularly in females. Our results suggest that food deprivation during short time (<36 h) can promote cold tolerance (especially survival after a cold stress) of D. suzukii flies. Future studies should address the ecological significance of these findings as short food deprivation may occur in the fields on many occasions and seasons

Association between retinal neovascularization and serial weight measurements in murine and human newborns

Introduction: Retinopathy of prematurity (ROP) is a leading cause of preventable blindness throughout the world. Several risk factors have been studied, but most studies remain inconclusive. Evidence is accumulating that one of the strongest predictors of ROP, in addition to oxygen use and low gestational age, is poor weight gain during the first postnatal weeks.
Methods: In a prospective study, we sought to determine the importance of serial weight measurements to help predict neovascularization (NV). In a first stage, a summary of the response in each case is identified and calculated as area under the curve (AUC). In a second stage, these different AUCs are analyzed by nonparametric Mann-Whitney U test. For the murine study, pups were redistributed in smaller and larger litters. On postnatal day (P)7-12, the oxygen-induced retinopathy (OIR) model was applied. Body weight was measured on P7, P14, and P17. Retinal NV was assessed on P17. For the human study, the subjects were part of the control arm of the NIRTURE trial. Ophthalmologists screened for ROP. Birthweight was recorded. Weekly weight measurements were performed for the first 4 weeks.
Results: The AUC of serial weight (gain) measurements was significantly lower in murine (14 vs 17 g; p = 0.01) and human (140 g/wk vs 240 g/wk; p = 0.0001) newborns developing retinal NV.
Conclusion: This prospective study supports previous findings, using a new way of statistical analysis, that early postnatal weight gain is an important indicator in the development of neovascular disease.status: publishe

Inoculative release strategies of Macrolophus pygmaeus Rambur (Hemiptera: Miridae) in tomato crops : population dynamics and dispersal

Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a key biological control agent in greenhouse tomato crops. In the present study, we describe the population dynamics of M. pygmaeus after release during two generations in semi-commercial greenhouses in order to optimize biocontrol programs. We tested the effect of the number of weekly supplementary food applications consisting of a mixture of Ephestia kuehniella Zeller and Artemia franciscana Kellogg in a tomato crop on population numbers of M. pygmaeus at low and high initial release densities of the predator. Also, the effect of supplementary feeding on the predator's dispersal was studied. Larger population densities of M. pygmaeus were obtained when food was supplied for a longer period. However, we observed fruit damage by M. pygmaeus at high densities resulting from too frequent food applications. Also, dispersal was slowed down as the number of supplementary food applications increased. Distributing M. pygmaeus over more plants at release results in higher total population densities. The optimal inoculative release strategy of M. pygmaeus is a trade-off between high population densities and fruit damage, fast or slow dispersal throughout the greenhouse and the number of release plants and work/costs related to the supplementation of food. The optimal strategy to overcome negative effects like fruit damage, slow dispersal and potential cannibalism proved to be a weekly provision of supplementary food during 6-8 weeks, with an initial release density strategy of 20 M. pygmaeus adults per plant. These results contribute to a more sustainable tomato production. A reliable and efficient inoculative release strategy for the key predator M. pygmaeus enhances the biocontrol potential and is of great value for tomato growers

Overwintering potential of the invasive leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) as a pest in greenhouse tomato production in Western Europe

The South American tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest in tomato crops. After having spread rapidly in the Mediterranean area since its first detection in 2006, it has recently become established in greenhouses in Western Europe. It was assumed that the low temperatures commonly associated with the winters in this area would prevent this exotic species from successful overwintering. However, the observed presence of T. absoluta at the start of the growing season in Belgium sparked a study on its potential to overwinter in Western Europe. In this study, the insect's cold hardiness and overwintering potential was assessed by determining: (1) the supercooling point (SCP) of larvae, pupae, and adults, (2) the lower lethal time (LT) for these stages at 0 and 5 A degrees C, and (3) the reproductive diapause incidence, as indicated by the reproductive performance of females reared at two temperatures (18 and 25 A degrees C) and two photoperiods [16:8 and 8:16 (L:D) h]. The mean SCP recorded for pupae (-16.7 A degrees C) was significantly higher than for adults (-17.8 A degrees C) and larvae (-18.2 A degrees C). Based on estimates of the LT adults demonstrated better cold hardiness than larvae and pupae at both 0 and 5 A degrees C with the median LT of adults averaging 17.9 and 27.2 days, respectively. No reproductive diapause was observed under the tested regimes. The results of this study indicate that T. absoluta is likely to successfully overwinter between two successive tomato crops in commercial greenhouses in Western Europe

Effect of starvation on the cold tolerance of Drosophila suzukii (Diptera: Drosophilidae) adults

International audienc