A quantitative trait variant in Gabra2 underlies increased methamphetamine stimulant sensitivity

Psychostimulant (methamphetamine, cocaine) use disorders have a genetic component that remains mostly unknown. We conducted genome-wide quantitative trait locus (QTL) analysis of methamphetamine stimulant sensitivity. To facilitate gene identification, we employed a Reduced Complexity Cross between closely related C57BL/6 mouse substrains and examined maximum speed and distance traveled over 30 min following methamphetamine (2 mg/kg, i.p.). For maximum methamphetamine-induced speed following the second and third administration, we identified a single genome-wide significant QTL on chromosome 11 that peaked near the Cyfip2 locus (LOD = 3.5, 4.2; peak = 21 cM [36 Mb]). For methamphetamine-induced distance traveled following the first and second administration, we identified a genome-wide significant QTL on chromosome 5 that peaked near a functional intronic indel in Gabra2 coding for the alpha-2 subunit of the GABA-A receptor (LOD = 3.6–5.2; peak = 34–35 cM [66–67 Mb]). Striatal cis-expression QTL mapping corroborated Gabra2 as a functional candidate gene underlying methamphetamine-induced distance traveled. CRISPR/Cas9-mediated correction of the mutant intronic deletion on the C57BL/6J background to the wild-type C57BL/6NJ allele was sufficient to reduce methamphetamine-induced locomotor activity toward the wild-type C57BL/6NJ-like level, thus validating the quantitative trait variant (QTV). These studies show the power and efficiency of Reduced Complexity Crosses in identifying causal variants underlying complex traits. Functionally restoring Gabra2 expression decreased methamphetamine stimulant sensitivity and supports preclinical and human genetic studies implicating the GABA-A receptor in psychostimulant addiction-relevant traits. Importantly, our findings have major implications for studying psychostimulants in the C57BL/6J strain—the gold standard strain in biomedical research.     

Does COMT genotype influence the effects of d‐amphetamine on executive functioning?

In a widely cited study, Mattay et al. reported that amphetamine (0.25 mg/kg oral, or 17 mg for a 68 kg individual) impaired behavioral and brain indices of executive functioning, measured using the Wisconsin Card Sorting Task (WCST) and N‐Back working memory task, in 6 individuals homozygous for the met allele of the val158met polymorphism in the catechol‐O‐methyltransferase (COMT) gene, whereas it improved executive functioning in 10 individuals homozygous for the more active val allele. We attempted to replicate their behavioral findings in a larger sample, using similar executive functioning tasks and a broader range of amphetamine doses. Over four sessions, n = 200 healthy normal adults received oral placebo, d‐amphetamine 5, 10, and 20 mg (average of 0.07, 0.15 and 0.29 mg/kg), under counterbalanced double‐blind conditions and completed WCST and N‐back tests of executive functioning. Amphetamine had typical effects on blood pressure and processing speed but did not affect executive functioning. COMT genotype (val158met) was not related to executive functioning under placebo or amphetamine conditions, even when we compared only the homozygous val/val and met/met genotypes at the highest dose of amphetamine (20 mg). Thus, we were not able to replicate the behavioral interaction between COMT and amphetamine seen in Mattay et al. We discuss possible differences between the studies and the implications of our findings for the use of COMT genotyping to predict clinical responses to dopaminergic drugs, and the use of intermediate phenotypes in genetic research.     

Factors affecting the bionomics of the eastern African egg parasitoid Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae)

The trichogrammatid Trichogramma bournieri Pintureau & Babault is a polyphagous parasitoid of eggs of several cereal stemborer species in eastern Africa. The effects of host species, host age and duration of host deprivation on the performance of the parasitoid were studied in the laboratory. Host acceptance and suitability were tested using five stemborer species. The noctuids Sesamia calamistis Hampson, Sesamia nonagrioides (Lefebvre), Busseola fusca (Fuller) the crambid Chilo partellus (Swinhoe) and the pyralid Eldana saccharina Walker were successfully parasitized by T. bournieri. Parasitism, number of progeny and developmental time varied significantly with host species. The eggs of S. calamistis and B. fusca were the most suitable, whereas those of E. saccharina were the least suitable. While parasitism and number of progeny tended to decrease with age of hosts, there were no significant differences in sex ratio. Longevity of the parasitoid increased with increase in deprivation of hosts from 0 to 12 days. Average lifetime fecundity per female decreased, indicating resorption of eggs.     

Overwintering of Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) within target and non-target host eggs

Trichogramma ostriniae was imported into the USA from China and it continues to be evaluated as a biological control agent against the European corn borer and other lepidopteran pest species. A natural enemy's ability to overwinter is a facet of its biology with important ramifications for biological control and non-target effects. Thus, studies were conducted to examine the ability of the introduced egg parasitoid to survive over winters in central New York State. Eggs of Ostrinia nubilalis, Ephestia kuehniella, Trichoplusia ni, Helicoverpa zea and Utetheisa ornatrix were subjected to parasitism by adult T. ostriniae and then placed out of doors and exposed to winter conditions. For trials initiated in 2003 and 2004, the adult parental wasps were exposed to a diapause-inducing photoperiod and temperature regime in the laboratory; in 2010, parental wasps were conditioned out of doors and prior to the onset of winter conditions. Emergence of their progeny was monitored over time by taking aliquots of parasitised eggs, and holding them under warm conditions until emergence was complete. The level of wasp emergence generally displayed a decline followed by gradual increase until spring. Levels of overwintering ranged from 1% for O. nubilalis to 76% for E. kuehniella, and logistic regression indicated that the odds of overwintering was dependent on the year, host species, time out of doors and varied over exposure time depending on host. The potential to overwinter in New York was further confirmed by positive identification of T. ostriniae from naturally occurring O. nubilalis eggs collected from field sites where augmentative releases had been made in previous years.     

室内外评价在黄淮海夏玉米区释放玉米螟赤眼蜂防治亚洲玉米螟的可行性

为了评价在黄淮海夏玉米区释放米蛾卵繁育的玉米螟赤眼蜂Trichogramma ostriniae防治亚洲玉米螟Ostrinia furnacalis的可行性,本试验在室内组建了玉米螟赤眼蜂在亚洲玉米螟卵上的实验种群生命表的基础上,在河南省鹤壁市滑县测定了玉米螟赤眼蜂对亚洲玉米螟的防治效果,筛选出了具有较好防治效果的释放密度和释放方法。结果显示,米蛾卵繁育的玉米螟赤眼蜂在亚洲玉米螟卵上的净生殖力R0为9.8240,单雌平均产雌率R0'为12.6256,2013年在河南省鹤壁市滑县释放玉米螟赤眼蜂能使亚洲玉米螟虫口密度减退73.91%,释放密度为2.25×105头/hm2。2014年在鹤壁市淇滨区钜桥镇采用传统的人工挂卡和新型的无人机释放玉米螟赤眼蜂,亚洲玉米螟虫口密度减退54.55%-68.16%。结果表明,在黄淮海夏玉米区释放米蛾卵繁育的玉米螟赤眼蜂防治玉米螟是可行的。     

温度对麦蛾卵繁育的玉米螟赤眼蜂发育和生殖的影响

玉米螟赤眼蜂Trichogramma ostriniae Pang et Chen是玉米螟的重要卵寄生性天敌,控制适宜的温度有利于室内大规模繁育。本试验以麦蛾卵为寄主,研究了不同温度(18℃、20℃、23℃、25℃、28℃、30℃、33℃、36℃)对玉米螟赤眼蜂的寿命、生殖力、子代羽化率和发育历期的影响。结果表明,20℃-25℃条件下雌蜂寿命最长,达7.9-9.0 d。在18℃-30℃亲代生殖力和子代羽化率无显著差异,亲代产卵量为40.9-61.7粒;羽化率为74.31%-84.22%。玉米螟赤眼蜂从卵到羽化的发育历期随温度的升高而显著缩短,由18℃时的22.6 d缩短至33℃的7.0 d。36℃时,雌蜂的寿命仅为0.56 d,且不能进行正常的生殖活动。因此,室内用麦蛾卵大规模繁育玉米螟赤眼蜂,适宜的温度为28℃-30℃;仅保存蜂种时,可选用温度18℃-20℃。     

松毛虫赤眼蜂两性生殖品系和孤雌产雌品系在不同品种柞蚕卵中的寄生和生长发育表现

[目的]明确两性生殖品系和孤雌产雌品系松毛虫赤眼蜂Trichogramma dendrolimi在不同品种柞蚕Antheraea pernyi卵中的寄生及发育表现,为以柞蚕卵为替代寄主更好地规模化繁育赤眼蜂提供依据.[方法]测定两性生殖品系和孤雌产雌品系雌蜂在6个品种柞蚕卵[抗大(KD)、大四(DS)、高新(GX)、9...     

(+)-Strigol,a witchweed seed germination stimulant,from Menispermum dauricum root culture

(+)-Strigol was isolated from Menispermum dauricum root culture filtrate. Its identity was confirmed by HPLC, 1H NMR, UV and MS, and on the basis of its CD spectrum. This is the first report on isolation of strigolactone from aseptic plant culture.     

Patch time allocation in male parasitoids

Abstract 1. Patch time allocation has been mostly studied in female parasitoids exploiting patches of hosts. Different parameters such as oviposition, host encounters, patch quality, etc. have been repeatedly shown to modify the time females invest on hosts. 2. Male parasitoids are expected to maximise their lifetime fitness by maximising the number of females inseminated during their life. Because they can be sperm and/or time limited, they should optimise their time allocation on emergence patches. 3. Patch time allocation thus appears to be an important question for both male and female parasitoids. 4. In this study, we determined the parameters used by males of the egg parasitoid Trichogramma turkestanica to decide when to leave the emergence patch. Among the different patch‐leaving parameters tested, only contacts with parasitised hosts and presence of virgin females significantly influenced the patch‐leaving tendency. 5. Our results suggest that males express behaviours that could enable them to optimise their patch exploitation time, as females do, but using different strategies.