斜纹夜蛾种群控制的研究概况

斜纹夜蛾Spodoptera litura(Fabricius)是重要的农业害虫之一。为了控制斜纹夜蛾,使农作物免受危害,前人研究了化学防治、杀虫灯和性诱捕器诱杀、植物诱集和驱避、转基因抗虫品种以及生物防治对其种群控制作用。化学防治在压制斜纹夜蛾种群暴发、减轻农作物遭受损失方面作出了巨大贡献,但日益增强的抗药性、农药残留造成的环境污染、对天敌的杀伤和人畜安全的影响等问题不断受到关注,人们开始对该害虫的一些新的治理策略进行了探讨。在这些无公害的控制技术中,植物诱集和生物防治是2种值得提倡的有效措施。不少植物源提取物和昆虫生长调节剂对斜纹夜蛾幼虫具有极好的效果,是值得研发的2种新型生物制剂。香芋和蓖麻等诱集作物对斜纹夜蛾有较好的诱集效果,如果能将作物诱集和释放天敌昆虫或病原微生物制剂结合,使之成为一套有效的生态控制体系,将可现实斜纹夜蛾种群的持续控制。     

苎麻田灯下金龟子种类组成及优势种群发生动态研究

为了调查苎麻田金龟子的种类及发生规律,于2013年4~9月,在湖北省咸宁市咸安区苎麻科技示范园进行了频振式杀虫灯诱虫试验,系统诱集金龟子并鉴定种类,分析灯下不同金龟子种群动态。结果表明：频振式杀虫灯在苎麻田诱集金龟子类4科10种,以铜绿丽金龟Anomala corpulenta Motschulsky和暗黑鳃金龟Holotrichia parallela Motschulsky为绝对优势种类。金龟子从4月末至9月初均灯下可见,5月中旬至6月上旬为铜绿丽金龟诱集高峰,6月上旬至7月中旬为暗黑腮金龟诱集高峰期。     

What is all the noise about in interval timing?

Cognitive processes such as decision-making, rate calculation and planning require an accurate estimation of durations in the supra-second range—interval timing. In addition to being accurate, interval timing is scale invariant: the time-estimation errors are proportional to the estimated duration. The origin and mechanisms of this fundamental property are unknown. We discuss the computational properties of a circuit consisting of a large number of (input) neural oscillators projecting on a small number of (output) coincidence detector neurons, which allows time to be coded by the pattern of coincidental activation of its inputs. We showed analytically and checked numerically that time-scale invariance emerges from the neural noise. In particular, we found that errors or noise during storing or retrieving information regarding the memorized criterion time produce symmetric, Gaussian-like output whose width increases linearly with the criterion time. In contrast, frequency variability produces an asymmetric, long-tailed Gaussian-like output, that also obeys scale invariant property. In this architecture, time-scale invariance depends neither on the details of the input population, nor on the distribution probability of noise.     

The evolution of the major histocompatibility complex in upstream versus downstream river populations of the longnose dace

Populations in upstream versus downstream river locations can be exposed to vastly different environmental and ecological conditions and can thus harbor different genetic resources due to selection and neutral processes. An interesting question is how upstream–downstream directionality in rivers affects the evolution of immune response genes. We used next‐generation amplicon sequencing to identify eight alleles of the major histocompatibility complex (MHC) class II β exon 2 in the cyprinid longnose dace (Rhinichthys cataractae) from three rivers in Alberta, upstream and downstream of municipal and agricultural areas along contaminant gradients. We used these data to test for directional and balancing selection on the MHC. We also genotyped microsatellite loci to examine neutral population processes in this system. We found evidence for balancing selection on the MHC in the form of increased nonsynonymous variation relative to neutral expectations, and selection occurred at more amino acid residues upstream than downstream in two rivers. We found this pattern despite no population structure or isolation by distance, based on microsatellite data, at these sites. Overall, our results suggest that MHC evolution is driven by upstream–downstream directionality in fish inhabiting this system.     

大猿叶虫滞育品系和非滞育品系交配行为的比较

大猿叶虫Colaphellus bowringi Blay是一种重要的十字花科蔬菜害虫,以成虫越冬和越夏。明确大猿叶虫非滞育品系生殖力下降的现象是否与交配行为的改变相关,将促进该非滞育品系在滞育遗传、滞育调控分子机制研究中的应用。本研究在25℃和L∶D=12∶12 h条件下,测定了大猿叶虫滞育品系和非滞育品系的交配节律、交配持续时间和交配频次。结果表明,大猿叶虫滞育品系和非滞育品系交配高峰均出现在光期开始后2 h,非滞育品系的交配比率显著低于滞育品系。滞育品系和非滞育品系第1次交配持续时间无显著差异,分别为122.7±7.4 min和100.1±10.2 min;但非滞育品系的总交配持续时间显著低于滞育品系。非滞育品系的交配频次为2.2±0.3次,显著低于滞育品系的3.8±0.5次。滞育品系和非滞育品系交配行为的比较发现,大猿叶虫非滞育品系生殖力降低与其交配比率下降、交配持续时间缩短和交配频次减少显著相关,本研究为进一步利用非滞育品系为材料解析滞育遗传、滞育调控机制奠定了基础。     

低频脉冲电场对PC12细胞酪氨酸羟化酶和多巴胺合成的影响

运用Western印迹和HPLC分别测定不同时间电场刺激和刺激后不同培养时间条件下,PC12细胞内酪氨酸羟化酶(TH)和细胞培养液中多巴胺(DA)含量的变化。结果显示,受到短时间(5、10min)脉冲电场刺激的PC12细胞,经较短时间(2天)的培养后,细胞内TH的含量和培养液中DA的含量均比对照组有所提高,但随着培养时间的延长(3~5天),TH和DA的含量均明显下降。然而,长时间(15、20、30min)脉冲电场刺激组则先表现为TH和DA的合成受到抑制,但随着培养时间的延长,其合成则被逐渐激活。采用蛋白激酶A(PKA)特异性抑制剂H-89和有丝分裂原活化蛋白激酶的激酶(MEK1/2)特异性抑制剂U0126,研究脉冲电场刺激所激活的与TH和DA合成相关的信号通路。结果表明,在没有神经生长因子(NGF)存在的情况下,PC12细胞主要通过PKA通路来激活TH的合成,低频脉冲电场刺激也主要激活PKA通路,因为抑制这条信号通路能显著抑制电场刺激所诱导的TH合成。     

WHBE兔血液蛋白的特性

目的比较大耳白黑眼兔（WHBE兔）与日本大耳白兔（JW兔）和新西澜兔（NZW兔）血液蛋白的多态性,从分子水平了解WHBE兔特殊性状的遗传背景。方法采用聚丙烯酰胺凝胶电泳对WHBE兔、JW兔和NZW兔血液中的前白蛋白（Pr）,后白蛋白（Po）,前转铁蛋白1（Prt1）,前转铁蛋白2（Prt2）,转铁蛋白1（Tf1）,转铁蛋白2（Tf2）,后转铁蛋白（Ptf）,慢α球蛋白（Sag）、血红蛋白（Hbα、Hbβ）和白蛋白（Alb）共11个蛋白位点进行检测。结果Pr、Ptf、Hbα、Hbβ、Alb、Po、Sag和Prt2在所有实验兔个体中的表型一致,而Tf1、Tf2和Prt1的表型在各实验兔品系间存在显著差异。在Tf1位点,NZW兔以BC表型为主,无AA型;JW兔只有AA型,而WHBE兔以AB型为主。在Tf2位点,NZW兔有AA型,而JW兔和WHBE兔无AA型。在Prt1位点,NZW兔无AB、BB和BC表型而有AC表型。NZW兔蛋白位点的平均杂合度大于JW兔和WHBE兔。JW兔与WHBE兔的遗传距离最近。结论Tf1、Tf2和Prt1可作为区分NZW兔、JW兔和WHBE兔的特征标记,并且与WHBE兔特殊性状形成有关。JW兔与WHBE兔的亲缘关系最近。     

Computational analysis of DNA photolyases using digital signal processing methods

Sun light energy is used by plants to trigger their growth and development. However, an increase of UV-B light may lead to DNA damage. DNA photolyases are enzymes that repair the cyclobutane pyridine dimer (CPD) and 6–4 photoproduct lesions formed through UV irradiation of DNA. Many aspects of the repair process are under intense scientific investigation but still poorly understood. Here we have computationally analysed DNA-photolyases using the resonant recognition model (RRM), a physico-mathematical approach based on digital signal processing methods. The RRM proposes that protein interactions represent the transfer of resonant electromagnetic energy between interacting molecules at the particular frequency. Within this study we have determined photolyases characteristic frequency, “hot spots” amino acids corresponding to the functional mutations and functional active/binding sites, and designed photolyase peptide analogous. A mutual relationship between photolyase and p53 tumour suppressor protein has also been investigated. The results obtained provide new insights into the structure–function relationships of photolyase protein family.     

Germ banks affect the inference of past demographic events

Continuous progress in empirical population genetics based on the whole‐genome polymorphism data requires the theoretical analysis of refined models in order to interpret the evolutionary history of populations with adequate accuracy. Recent studies focus prevalently on the aspects of demography and adaptation, whereas age structure (for example, in plants via the maintenance of seed banks) has attracted less attention. Germ banking, that is, seed or egg dormancy, is a prevalent and important life‐history trait in plants and invertebrates, which buffers against environmental variability and modulates species extinction in fragmented habitats. Within this study, we investigate the combined effect of germ banking and time‐varying population size on the neutral coalescent and particularly derive the allele frequency spectrum under some simplifying assumptions. We then perform an ABC analysis using two simple demographic scenarios—a population expansion and an instantaneous decline. We demonstrate the appreciable influence of seed banks on the estimation of demographic parameters depending on the germination rate with biases scaled by the square of the germination rate. In the more complex case of a population bottleneck, which comprises an instantaneous decline and an expansion phase, ignoring information on the germination rate denies reliable estimates of the bottleneck parameters via the allelic spectrum. In particular, when seeds remain in the bank over several generations, recent expansions may remain invisible in the frequency spectrum, whereas ancient declines leave signatures much longer than in the absence of seed bank.     

Effect of organic and mineral fertilizers on N-use by wheat under different irrigation frequencies

A field trial was established in Errachidia, southern Morocco, to investigate the interaction between wheat residue management and mineral 15N-labelled ammonium sulphate, under different irrigation treatments, applied to wheat (Triticum durum var. Karim). In treatments I1, I2, I3 and I4, plots were irrigated every 10, 15, 21 and 30 days. Each plot contained three sub-plots that received three fertilization treatments: T1 received 42 kg N ha-1 of ammonium sulphate before seedling, 42 kg N ha-1 of ammonium sulphate labelled with 9.764 at % 15N excess at tillering and 84 N kg ha-1 of ammonium sulphate at flowering; T2 received 42 kg N ha-1 of ammonium sulphate labelled with 9.764 at % 15N excess at seedling, 42 kg N ha-1 at tillering and 42 kg N ha-1 at flowering; T3 received 4800 kg ha-1 of wheat residue labelled with 1.504 at % 15N excess and 42 kg N ha-1 of ammonium sulphate before seedling and 42 kg N ha-1 of ammonium sulphate at flowering. Nitrogen fertilization with 168 kg N ha-1 did no significantly increase grain and straw yields in comparison to the 126 kg N ha-1 application. The combination of the organic input and supplementary application of mineral fertilizer N has been found as a more attractive management option. For all irrigation treatments, the % recovery of N in the whole plant was higher in plants that received 15N at tillering (63%, 49% respectively for irrigation intervals between 10 and 30 d) than in plants that received 15N just after seeding (28% for irrigation each 10- and 30-d intervals). For the irrigation treatment each 10 and 15 days, the 15N was mainly recovered by the grain for all fertilization treatments, whereas for irrigation treatment each 30 days, the grain and straw recovered nearly equal amounts of fertilizer. For grain and straw of wheat, nitrogen in the plant derived from the fertilizer was low, while most of the N was derived from the soil for all irrigation and fertilization treatments. The % nitrogen in the plant derived from the fertilizer values showed no significant difference between the different plant parts. The results suggested a dominant influence of moisture availability on the fertilizer N uptake by wheat. Under dry conditions the losses of N can be allotted to denitrification and volatilisation.