Disulfide connectivity and reduction in pheromone-binding proteins of the gypsy moth, Lymantria dispar

Males of the gypsy moth, Lymantria dispar, are attracted by a pheromone released by females. Pheromones are detected by olfactory neurons housed in specialized sensory hairs located on the antennae of the male moth. Once pheromone molecules enter the sensilla lymph, a highly abundant pheromone-binding protein (PBP) transports the molecule to the sensory neuron. The PBPs are members of the insect odorant-binding protein family, with six conserved cysteine residues. In this study, the disulfide bond connectivities of the pheromone-binding proteins PBP1 and PBP2 from the gypsy moth were found to be cysteines 19–54, 50–109, and 97–118 for PBP1, and cysteines 19–54, 50–110, and 97–119 for PBP2, as determined by cyanylation reactions and cyanogen bromide chemical cleavage. We have discovered that the second disulfide linkage is the most easily reduced of the three, and this same linkage is missing among four cysteine-containing insect odorant-binding proteins (OBPs). We are the first to identify the unique steric and electronic properties of this second disulfide linkage. Electronic Supplementary Material  Supplementary material is available for this article at

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Attractants from Bartlett pear for codling moth, Cydia pomonella (L.), larvae

The alkyl ethyl and methyl esters of (2E,4Z)-2,4-decadienoic acid found in head-space samples of ripe Bartlett pear (Pyrus communis L.) stimulated a response from neonate larvae of the codling moth (CM), Cydia pomonella (L.), in both static-air Petri-plate and in upwind Y-tube and straight-tube olfactometer bioassays. In comparison with the known CM neonate attractant, (E,E)-!-farnesene, ethyl (2E,4Z)-2,4-decadienoate was attractive at 10-fold and 1,000-fold lower threshold dosages in the Petri-plate and in the Y-tube bioassays, respectively. Methyl (2E,4Z)-2,4-decadienoate was attractive to CM neonates in these bioassays at much higher doses than ethyl (2E,4Z)-2,4-decadienoate. Other principal head-space volatiles from ripe pear fruit and pear leaves, including butyl acetate, hexyl acetate, (Z)-3-hexenyl acetate, and (E)-#-ocimene, were not attractive to CM neonates. The potential uses of these pear kairomones for monitoring and control of CM in walnuts and apple are discussed.     

Selection on worker honeybee responses to queen pheromone (Apis mellifera L.)

 Disruptive selection for responsiveness to queen mandibular gland pheromone (QMP) in the retinue bioassay resulted in the production of high and low QMP responding strains of honeybees (Apis mellifera L.). Strains differed significantly in their retinue response to QMP after one generation of selection. By the third generation the high strain was on average at least nine times more responsive than the low strain. The strains showed seasonal phenotypic plasticity such that both strains were more responsive to the pheromone in the spring than in the fall. Directional selection for low seasonal variation indicated that phenotypic plasticity was an additional genetic component to retinue response to QMP. Selection for high and low retinue responsiveness to QMP was not an artifact of the synthetic blend because both strains were equally responsive or non-responsive to whole mandibular gland extracts compared with QMP. The use of these strains clearly pointed to an extra-mandibular source of retinue pheromones (Pankiw et al. 1995; Slessor et al. 1998; Keeling et al. 1999). Received: 2 March 2000 / Accepted in revised form: 4 September 2000     

A pear-derived kairomone with pheromonal potency that attracts male and female codling moth, Cydia pomonella (L.)

Ethyl (2E, 4Z)-2,4-decadienoate, a pear-derived volatile, is a species-specific, durable, and highly potent attractant to the codling moth (CM), Cydia pomonella (L.), a serious pest of walnuts, apples, and pears worldwide. This kairomone attracts both CM males and virgin and mated females. It is highly attractive to CM in both walnut and apple orchard contexts, but has shown limited effectiveness in a pear orchard context. Rubber septa lures loaded with ethyl (2E, 4Z)-2,4-decadienoate remained attractive for several months under field conditions. At the same low microgram load rates on septa, the combined gender capture of CM in kairomone-baited traps was similar to the capture rate of males in traps baited with codlemone, the major sex pheromone component. The particular attribute of attracting CM females renders this kairomone a novel tool for monitoring population flight and mating-ovipositional status, and potentially a major new weapon for directly controlling CM populations.     

Arsenic uptake, accumulation and phytofiltration by duckweed （Spirodela polyrhiza L.）

This study investigates arsenic (As) accumulation and tolerance of duckweed Spirodela polyrhiza L: and its potential for As phytofiltration. S. polyrhiza was able to survive in high concentration of As(V) solution: The EC50 values ( SE) based on the external As(V) were (181.66 20.12) mol/L. It accumulated (999 95) mg As/kg dw when exposed in 320 mol/L As(V) solution for one week, and was able to take up appropriately 400 mg As/kg dw in tissues without a significant biomass loss. The EC50 values (the e ective concentration of As(V) in the nutrient solution that caused a 50% inhibition on biomass production) was (866 68) mg/kg dw for the tissues, indicating that S. polyrhiza had a high capability of As accumulation and tolerance. The uptake kinetic parameters Vmax was (55.33 2.24) nmol/(g dw min) and Km was (0.144 0.011) mmol/L. Within 72 hr, S. polyrhiza decreased As concentration in the solution from 190 to 113 ng/mL with a removal rate of 41%. The study suggested that this floating aquatic plant has some potential for As phytofiltration in contaminated water bodies or paddy soils.     

Uptake of NO,NO2 and O3 by sunflower (Helianthus annuus L.) and tobacco plants (Nicotiana tabacum L.): dependence on stomatal conductivity

The uptake of NO, NO₂ and O₃ by sunflowers (Helianthus annuus L. var. giganteus) and tobacco plants (Nicotiana tabacum L. var. Bel W3), using concentrations representative for moderately polluted air, has been determined by gas exchange experiments. Conductivities for these trace gases were measured at different light fluxes ranging from 820 μEm⁻²s⁻¹ to darkness. The conductivities to water vapor and the trace gases are highly correlated. It is concluded that the uptake of NO, NO₂ and O₃ by sunflowers and tobacco plants is linearly dependent on stomatal opening. While the uptake of NO is limited by the mesophyll resistance, the uptake of NO₂ is only by diffusion through the stomata. Loss processes by deposition to the leaf surfaces are more pronounced for O₃ than for NO and NO₂.     

Evaluation of Steinernema feltiae and S. bibionis (Rhabditida: Steinernematidae) for suppression of Lymantria dispar (Lepidoptera: Lymantriidae) in Pennsylvania,U.S.A.

Lymantria dispar L. larvae exposed to the entomogenous nematodes Steinernema feltiae Filipjev and S. bibionis (Bovien) for ⩾ 16 h in laboratory petri dish tests averaged 93 and 91% mortality, respectively. Nylon pack cloth bands, lined with Pellon fleece or terry cloth, placed around oak tree boles were treated with nematode suspensions in central Pennsylvania. Fifth and 6th stage host larvae collected from beneath these bands after nematode treatment averaged 28% mortality.     

瑞典沿岸水域濒临消失的大叶藻(Zostera Marina,L.)

在瑞典斯卡格拉克海峡沿岸,大叶藻(Zostera marina)是一种生长在浅水软海底上的优势显花植物.大叶藻场是许多甲壳动物和鱼类,不管是洄游种或是稳定种的重要群落生境.在20世纪80年代期间,作为海岸带管理的基础,对瑞典西海岸有大叶藻生长的沿岸浅水区的资源进行了调查.在这次研究中我们再次考察了斯卡格拉克海峡200km沿岸的5个沿海地区中的2000hm2大叶藻场.资源调查的方法(水下测量镜)与80年代的一样,但通过使用全球定位系统(GPS)增加了绘图的精确度.这次研究的结果表明,在10～15年的时间里,大叶藻的区域延伸面积减少了58%,且地区变化很大.大叶藻的减少主要限于大叶藻场的浅水部分.本文探讨了原因和生态后果.     

Insecticide resistance may enhance the response to a host-plant volatile kairomone for the codling moth, <Emphasis Type="Italic">Cydia pomonella</Emphasis> (L.)

The behavioral and electroantennographic responses of Cydia pomonella (L.) to the ripe pear volatile ethyl (2E,4Z)-2,4-decadienoate (Et-E,Z-DD), were compared in insecticide-susceptible and -resistant populations originating from southern France. A dose–response relationship to this kairomonal attractant was established for antennal activity and did not reveal differences between susceptible and resistant strains. Conversely, males of the laboratory strains expressing metabolic [cytochrome P450-dependent mixed-function oxidases (mfo)] or physiological (kdr-type mutation of the sodium-channel gene) resistance mechanisms exhibited a significantly higher response to Et-E,Z-DD than those of the susceptible strain in a wind tunnel experiment. No response of the females to this kairomone could be obtained in our wind-tunnel conditions. In apple orchards, mfo-resistant male moths were captured at significantly higher rates in kairomone-baited traps than in traps baited with the sex pheromone of C. pomonella. Such a differential phenomenon was not verified for the kdr-resistant insects, which exhibited a similar response to both the sex pheromone and the kairomonal attractant in apple orchards. Considering the widespread distribution of metabolic resistance in European populations of C. pomonella and the enhanced behavioral response to Et-E,Z-DD in resistant moths, the development of control measures based on this kairomonal compound would be of great interest for the management of insecticide resistance in this species.     

利用水浮莲(Pistia stratiotes L.)净化城市污水的实践

将城市污水的流量控制在400m3/d左右的条件下,在3200m2池面水浮莲净化塘内进行净化处理.结果表明,在滞留处理时间为8d时, SS、BOD5、CODCr、NH4-N与色度的去除率分别保持在91.85%、84.54%、81.91%、61.88%、86.96%以上,净化水的理化指标达到二级排放标准;细菌总数与大肠杆菌群总数的剩余率也仅为净化前的0.0078%和0.075%,水的卫生指标也得到明显改善.     

紫云英(Astragalus siniucus L.)对重金属胁迫的响应

为探明铜冶炼厂附近农田重金属污染对冬季绿肥作物的毒害作用,通过盆栽试验,研究了浙江富阳铜冶炼厂附近的铜、锌、铅等重金属离子混合污染的水稻土上,紫云英的生长,根、茎、叶、果各部位重金属积累量和细胞超微结构的变化.结果表明,在供试土壤重金属混合污染下,紫云英根系生长缓慢,主根细小、侧根稀少,根瘤生长受抑制;地上部分枝减少,长势矮小,叶片黄化,花期推迟.土壤中铜、锌、铅被紫云英吸收后主要分布于紫云英根部;根中铜含量明显高于锌和铅,茎、叶中锌含量最高,果中铜含量最低.透射电镜(TEM)观察结果表明,重金属混合污染主要毒害叶绿体、线粒体、细胞核等细胞器的超微结构,使叶绿体膨胀变形,基粒片层解体,外膜结构消失,类囊体模糊不清,腔内空泡化或形成大脂类;使线粒体变形、脊突膨胀或消失、外膜解体;使细胞核核膜破裂、核仁膨胀消失并与染色质凝集在一起.供试土壤重金属混合污染对紫云英各部位细胞的破坏程度为根>叶>茎.     

钼作用下油菜对镉胁迫的生理生化响应及其对镉吸收的特征

为了探讨施钼对不同浓度镉胁迫油菜的缓解效果,利用盆栽试验,研究了4种外源钼梯度（0、50、100、200 mg·kg^-1）对低镉（0.5 mg·kg^-1）和高镉（6.0 mg·kg^-1）两种胁迫下油菜生理生化、生物量、镉的转运富集等的影响作用.结果显示,外源钼可促进镉胁迫油菜长度、鲜重、干重增加.不同浓度的钼可使镉胁迫油菜生理生化指标丙二醛（MDA）、脯氨酸（Pro）积累量显著降低,可溶性蛋白（SP）含量、可溶性糖（SS）含量、叶绿素（Chla和Chlb）含量、超氧化物歧化酶（SOD）活性和谷胱甘肽过氧化物酶（GPX）活性显著提高;同时,施入钼能够有效抑制油菜对镉的吸收富集,但对其转运影响相对较小,同时又可显著提高油菜对镉的耐性.钼对镉的抑制作用表现为提高油菜的生物量水平、改善其生理生化性能,通过参与油菜生理过程降低油菜对镉的吸收,进而提高油菜对进入体内镉的耐受力,外源钼能有效地降低Cd胁迫对油菜的毒害.     

Combined toxicity of copper and cadmium to six rice genotypes （Oryza sativa L.）

Accumulation of copper (Cu) and cadmium (Cd) in six rice cultivars (94D-22, 94D-54, 94D-64, Gui630, YY-1 and KY1360) was evaluated through exposure to heavy metal contamination (100 mg/kg Cu, 1.0 mg/kg Cd, and 100 mg/kg Cu + 1.0 mg/kg Cd) in a greenhouse. The dry weight of shoot and root, concentrations of Cu and Cd in plant tissues and the Cu, Cd, P, Fe concentrations in the root surface iron plaques were analyzed eight weeks later after treatment. The results indicated that the plant biomass was mainly determined by rice genotypes, not Cu and Cd content in soil. Separated treatment with Cu/Cd increased each metal level in shoot, root and iron plaques. Soil Cu enhanced Cd accumulation in tissues. In contrast, Cu concentrations in shoot and root was unaffected by soil Cd. Compared to single metal contamination, combined treatment increased Cd content by 110.6%, 77.0% and 45.2% in shoot, and by 112.7%, 51.2% and 18.4% in root for Gui630, YY-1 and KY1360, respectively. The content level of Cu or Cd in root surface iron plaques was not affected by their soil content. Cu promoted Fe accumulation in iron plaques, while Cd has no effect on P and Fe accumulation in it. The translocation of Cu and Cd from iron plaques to root and shoot was also discussed. These results might be beneficial in selecting cultivars with low heavy metal accumulation and designing strategies for soil bioremediation.