Structural studies and photochemical re-arrangement of an animal metabolite of HEOD,the active component of dieldrin

The structure of 9-hydroxy HEOD was examined by spectroscopic methods and by photolysis. The hydroxyl group was found to be hydrogen bonded to the epoxy group, and the product of photolysis was a hydroxylated analogue of the previously described photoisomer of HEOD.     

Residues of organochlorine pesticides in broilers from feed fortified with known levels of these compounds

p, p'-DDT, HEOD, endrin, heptachlor epoxide, hexachlorobenzene and lindane were fed in combination to day-old broiler chickens at levels of 0.05, 0.15 and 0.30 part/million in the feed, for a period of about 7 weeks. Birds were killed at regular intervals and samples of abdominal fat and other tissues examined for residues of the chlorinated pesticides by gas-liquid chromatography. The lipid content of each sample was determined and the residue levels calculated for the whole tissue and also for the fat contained in the sample. At the end of the 7 weeks (when in practice broilers are slaughtered) residues were highest for heptachlor epoxide, followed by hexachlorobenzene, HEOD, DDT (total), endrin, and lindane. Heptachlor epoxide residue levels in fat were 13 times the levels in the feed, for lindane the ratio was 3.3. Fat residues of each pesticide reached a plateau level relatively quickly, and these levels were proportional to the fortification rates in the feed. HEOD and p, p'-DDT alone were fed to separate groups of birds. No differences in residue build-up of these compounds were found between these groups and the groups that had received these compounds in combination with the other pesticides. The total amounts of each pesticide in the tissues were reduced when the meat was fried, probably by loss of fat during preparation and frying. For p, p'-DDT and heptachlor epoxide also smaller residue were observed in the remaining fat after frying.     

Synthesis and structural studies of 9-Anti-hydroxy HEOD

9-Syn-hydroxy HEOD, a major mammalian metabolite of HEOD was oxidised to the ketone which, on reduction with sodium borohydride, gave a product identified by spectrometric methods as 9-anti-hydroxy HEOD. This product was not converted to the pentachloroketone metabolite of HEOD, either by photolysis or metabolically by a rat.     

Pharmacological evidence for a discrete neurotoxic action of dieldrin (HEOD) in the American cockroach,Periplaneta americana (L.)

The excitatory effects of HEOD poisoning on spontaneous activity, and synaptic function in the sixth abdominal ganglion of the American cockroach are described. These effects are shown to be antagonized by Mg²⁺, hemicholinium-3, atropine, and d-turbocurarine. HEOD poisoning did not alter the nicotine sensitivity of the ganglion. On the basis of the findings it is hypothesized that HEOD acts at presynaptic membranes of cholinergic junctions, causing excessive and spontaneous release of presynaptic stores of acetylcholine.     

Effects of nereistoxin on the neuroexcitatory action of insecticides

Nereistoxin suppressed the excitatory actions of α- and γ-BHC and HEOD in the central nervous system of Periplaneta americana (L.). However, it did not affect the neurotoxic action of DDT and DBrDT. Since nereistoxin is an acetylcholine antagonist, it is postulated that BHC and HEOD act to produce high level of acetylcholine and the resulting after-discharges, while DDT and DBrDT seem to attack the noncholinergic region of insect nervous system.     

Von Baeyer/IUPAC names and abbreviated chemical names of metabolites and artifacts of aldrin (HHDN), dieldrin (HEOD) and endrin

The correct von Baeyer/IUPAC names of aldrin (HHDN), dieldrin (HEOD), and endrin, of 5 previously incorrectly-named compounds and of 18 other related compounds which have not hitherto been named in this way are presented in tabular form alongside their structural formulae. The von Baeyer ring systems present in some of these compounds were identified by inspection of Schlegel diagrams (planar representation of bridged hydrocarbons), a guide to the construction of which is presented. Also included in the tables (which have been indexed) are abbreviated chemical names; the suitability of the choices made is discussed. The alternative “polyhydroaromatic” names for 12 of these compounds have been abstracted from the literature and listed.     

Effects of dieldrin (HEOD) and some of its metabolites on synaptic transmission in the frog motor end-plate

The effects of HEOD and some of its metabolites on synaptic transmission in the frog motor end-plate were studied by means of intracellular microelectrodes. HEOD itself and the metabolites 9-syn-hydroxy-HEOD and the aldrin-derived dicarboxilic acid had no significant effect on frequency and amplitude of miniature end-plate potentials, nor on end-plate membrane potential. In sharp contrast with this aldrin-transdiol (6,7-trans-dihydroxy-dihydro-aldrin) was very potent in exerting both pre- and postsynaptic actions. This metabolite caused a rapid and marked increase in miniature end-plate potential frequency, together with a decrease in their amplitude. Evidence is presented suggesting that the spontaneous transmitter release is enhanced by two prejunctional mechanisms: partly by a calcium-dependent effect, probably a depolarization of the nerve terminal, and partly by a calcium-independent action. Another typical prejunctional action of aldrin-transdiol is the reduction of the amount of transmitter released in response to high external potassium concentration. Aldrin-transdiol also affected the evoked transmitter release and caused a marked increase in end-plate potential amplitude followed by a decrease, and finally a complete blockade of neuromuscular transmission was observed. This transient increase in transmitter release was shown to be due to a transient increase in quantal content. The subsequent fall in end-plate potential amplitude and the fall in miniature end-plate potential amplitude are probably the result of a reduction of the sensitivity of the postsynaptic membrane to acetylcholine as demonstrated by ionophoretic application of this transmitter. There was no aldrin-transdiol-effect on the end-plate membrane potential. The present results strongly support the hypothesis that HEOD must be converted to aldrin-transdiol before it can exert its neurotoxic action.     

Residues of organochlorine insecticides in some fishes and birds in the gezira of Sudan

Twenty-eight specimens representing five types of fish and five types of birds from the Gezira Research Farm, Wad Medani, Sudan, were analysed for residues of organochlorine insecticides. All fish muscle samples were found to contain pp′-DDE, pp′-TDE and pp′-DDT in total concentrations ranging from 0.27 to 16.0 mg/kg. In addition to DDT-type residues, dieldrin (HEOD) was also found in the majority of bird samples. Concentrations in bird breast muscle ranged from 0.07 to 5.5 mg/kg. When bird liver samples were examined they were found to contain higher residues than the breast muscle in nearly all cases.     

Biological control of the tick fowl Argas persicargas persicus by the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae

The pathogenicity of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae against the tick fowl Argas persicargas persicus was studied. Bioassays revealed significant differences between the two fungi and the A. persicargas persicus stages exposed. The first nymphal instar was more highly susceptible to both fungi than the second nymphal instar. The unfed female of A. persicargas persicus was significantly less susceptible to both fungi than the engorged female. Application of M. anisopliae to sackcloth naturally infested with the tick fowl A. persicargas persicus induced mortality which reached 100% three weeks after treatment under field conditions. The present study suggests that entomopathogenic fungi have good potential for tick fowl, A. persicargas persicus, control.     

创制农药氯啶菌酯对小麦白粉病防治效果

对我国新创制的甲氧基丙烯酸酯类杀菌剂氯啶菌酯防治小麦白粉病进行了试验。小麦白粉病菌孢子萌发抑制试验表明,20、10、1 μg/mL氯啶菌酯对孢子萌发的抑制率为83.54%、67.78%、19.24%。室内盆栽试验确定氯啶菌酯对小麦白粉病的EC50为4.172 3 μg/mL。田间试验结果表明,15%氯啶菌酯乳油有效用量60、40 g/hm2防治效果极显著高于20 g/hm2,与对照15%三唑酮可湿性粉剂防效相当。     

Parietaria mottle virus, a possible new ilarvirus from Parietaria officinalis (Urticaceae)

A previously undescribed virus, probably a new member of the ilarvirus group, was isolated from Parietaria officinalis showing symptoms of yellow mosaic or mottling. This virus, for which the name parietaria mottle virus (ParMV) is proposed, differs in host range from other ilarviruses. ParMV was purified from Chenopodium quinoa by sap clarification with chloroform, and differential and sucrose density gradient centrifugation.
Purified particles were quasi-isometric to ovoid with diameters of about 24, 29 and 36 nm; no bacilliform particles were detected. Buoyant density in caesium chloride, determined on glutaraldehyde-fixed virus, was 1.35 g/cm³.
An antiserum to ParMV was obtained with a titre of 1:32 in agar gel double-diffusion tests. ParMV did not react with eight other viruses or virus strains belonging to the ilarvirus group or to pelargonium zonate spot virus.
Polyacrylamide gel electrophoresis indicated that ParMV contains a single major protein species of estimated molecular weight 24300 Da and four RNA species of estimated molecular weight 1 37, 1.19, 0.86 and 0.36 × 10⁶ Da.     

Sensitivity of Fusarium moniliforme Isolates to Ipconazole

To estimate the sensitivity of Fusarium moniliforme to ipconazole, a sterol biosynthesis inhibitor (SBI), minimum inhibitory concentrations (MIC) were determined for isolates which were collected before the launch of ipconazole as a rice seed disinfectant. Research institutes from various prefectures in Japan supplied 211 isolates (group I) from their collections, and 84 isolates (group II) were isolated from rice paddy fields in Iwaki, Fukushima Prefecture. In group I, the MIC ranged from 0.10 to 6.25 μg/ml with a peak at 0.39 μg/ml. In group II, MIC values had the same range as group I, but the main peak was at 0.20 μg/ml. Ipconazole sensitivity did not differ significantly among groups I and II. Though the ranges of MIC values for ipconazole, pefurazoate and triflumizole were different in 60 isolates randomly chosen from group I, positive correlations were observed in their sensitivities to SBIs, suggesting a common mechanism in F. moniliforme for lowering sensitivities to SBIs. Among the 14 isolates tested, isolates with MIC values lower than 0.78 μg/ml for ipconazole were pathogenic to rice seedlings, and all the isolates with MIC values higher than or equal to 1.56 μg/ml were not pathogenic in the nursery test. Good protection against isolates causing “Bakanae” disease was obtained by dipping seeds for 24 hr in ipconazole. The pathogenic isolates can be controlled by the seed treatment with the practical dosage of ipconazole because of the adequate margin between the highest MIC value for the pathogenic isolates and the treatment concentration. In addition, the low or lack of pathogenicity of the isolates less sensitive to ipconazole may also contribute to the stable efficacy of ipconazole. Received 8 November 1999/ Accepted in revised form 18 April 2000     

低浓度Bt杀虫蛋白连续刺激对甜菜夜蛾飞翔力的影响

以人工饲料中添加低浓度的Cry1Ac杀虫蛋白(0、5、10、20μg/g)饲养甜菜夜蛾5个世代,探讨低浓度杀虫蛋白连续刺激对该虫处女蛾与产卵蛾飞行速度、飞行时间与飞行距离的影响。结果表明,甜菜夜蛾对低浓度Bt毒素的响应经过了敏感期、逐步适应期到最终适应甚至反弹几个阶段:在F1代,对照组的飞行距离显著长于最高浓度处理组。F2、F3代,低浓度处理(5~10μg/g)后的甜菜夜蛾飞行力开始增强,高浓度杀虫蛋白处理组(20μg/g)的飞行力仍低于对照,不同处理在飞行时间与飞行距离上差异显著。在F4代,处女蛾的飞行力开始回升,特别是低浓度处理(5μg/g)的飞行时间和飞行距离显著高于对照,也显著或极显著高于其他2个浓度处理,各处理在飞行时间和飞行距离上达到显著差异。到了F5代,所有处理的飞行力均大于对照,其飞行速度、飞行时间与飞行距离3个指标在各处理间均达到显著差异。研究同时发现,无论是处女蛾,还是产卵雌蛾,对低浓度Cry1Ac杀虫蛋白的响应基本一致。文章认为,阐述毒蛋白对昆虫飞行的影响需要研究多个世代。     

溴甲烷和磷化氢熏蒸杂交稻种对米象和干尖线虫的杀灭效果及对水稻发芽率的影响

在10~15 ℃、16~20 ℃、21~30 ℃3个温度范围下,不同剂量的溴甲烷、磷化氢熏蒸出口杂交稻种的试验表明：溴甲烷、磷化氢能有效地杀灭米象,但不能完全杀灭干尖线虫。熏蒸后对杂交稻种的发芽率检测表明磷化氢对杂交稻种表现安全,但16~20 ℃下,40 g/m3溴甲烷及21~30 ℃下,32 g/m3溴甲烷熏蒸处理24 h,杂交稻种子发芽率显著降低。     

马铃薯晚疫病菌对烯酰吗啉的敏感性基线及其室内抗药突变体的研究

 2003-2004年在内蒙古和黑龙江省共分离获得100株马铃薯晚疫病菌,并测定了这些菌株对烯酰吗啉和甲霜灵的敏感性。结果表明,不同地区、不同年份的马铃薯晚疫病菌对烯酰吗啉的敏感性无显著差异,其敏感性呈连续的单峰曲线分布,EC₅₀在0.0631-0.2206μg/mL之间,最不敏感菌株是最敏感菌株的3.1倍,平均为(0.1153±0.0308)μg/mL,未出现敏感性下降的抗药性亚群体,因此可作为马铃薯晚疫病菌对烯酰吗啉的敏感性基线;64%的供试菌株对甲霜灵的敏感性下降,甲霜灵与烯酰吗啉之间不存在交互抗药性。采用紫外线诱变菌丝的方法仅从3个菌株中的1个菌株获得了3%突变频率的抗烯酰吗啉突变体,抗性倍数为1.5-1.9,没有获得高抗药水平的突变体。这些突变体与氟吗啉之间具有正交互抗药性,而与霜脲氰或嘧菌酯之间无交互抗药性;与野生亲本菌株相比,抗药突变体的生长速率和产孢子囊能力显著下降,不利于抗药群体的发展。但由于马铃薯晚疫病菌被杀菌剂抗性行动委员会认为是高抗药性风险病原菌,建议生产上应将烯酰吗啉与其它无交互抗性的药剂交替使用或混合使用,以避免或延缓抗药性的产生。     

Toxicity of spray and fumigant products containing cassia oil to Dermatophagoides farinae and Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

The toxicity of formulations of oil of cassia, Cinnamomum cassia Blume, (20 and 50 g L(-1) sprays and 100% oil-based fumigant) to adult Dermatophagoides farinae Hughes and D. pteronyssinus Trouessart was examined using contact and vapour-phase toxicity bioassays. Results were compared with the lethal activity of three commercial acaricides: benzyl benzoate, dibutyl phthalate and diethyl-m-toluamide (deet). The contact toxicity of cassia oil to both dust mite species was comparable with that of benzyl benzoate but was higher than that of the other two acaricides. Sprays containing 20 and 50 g L(-1) cassia oil were effective against both mite species when applied to fabric, glass, paper, plastic, tin or wood substrates. Applications of the 50 g L(-1) spray to different space volumes and surface areas determined that 50-60 mg of cassia oil was needed to control dust mites in 3.4 m(3) or in 1 m(2). In tests with fumigant devices, toxicity varied according to the thickness of non-woven fabric covering the device, the exposure time, the number of fumigant devices used and the volume of the space sprayed. Fumigant toxicity to adult D. pteronyssinus was more pronounced with devices enclosed in thinner (40 microm) versus thicker (45 or 50 microm) non-woven fabric covers. A single fumigant device with a 40 microm thick non-woven fabric cover resulted in substantial control in a space of 0.05 m(3) but exhibited only moderate to weak control in spaces >or= 0.097 m(3) at 4 days after application. Two fumigant devices gave 88% mortality in a space of 1.73 m(3). Cassia oil applied as sprays or in fumigant devices appears to provide effective protection of humans from house dust mites.     

解淀粉芽胞杆菌DS-1菌剂的研制及田间应用效果

本文以一株解淀粉芽胞杆菌DS-1生防菌为研究对象,采用单因素法和正交试验法优化该菌株的发酵条件和生产工艺,通过菌剂的研制测定了其温室防效。结果表明:该菌株最佳固态发酵为以玉米粉为基质,培养条件为可溶性淀粉200 mg/g、小米粉50 mg/g、接种量0.8 mL/g、培养时间96 h、pH 8.0;最适的菌株助剂为壳聚糖20 mg/g(载体)、聚四氟乙烯浓缩分散液100 mg/g(分散剂)和糊精50 mg/g(保护剂)。粉剂与颗粒剂均能提高番茄和黄瓜的株高和鲜重,且颗粒剂效果更突出;并对辣椒枯萎病的防治效果可达60.75%和62.86%,对黄瓜枯萎病的防效达63.58%和66.12%,两种制剂的防效均显著高于发酵液的防效。     

七种杀虫剂对暗黑鳃金龟成虫和幼虫的毒力及田间防控效果

为筛选防治暗黑鳃金龟Holotrichia parallela的有效药剂,用浸虫法测定了7种药剂对暗黑鳃金龟幼虫的毒力,分别采用浸虫法、浸叶法、药膜法测定了7种药剂对其成虫的毒力,并通过大田试验作了进一步验证。浸虫法测得高效氯氟氰菊酯对成虫的毒力最高,LC₅₀值为1.38 mg/L;浸叶法测得辛硫磷毒力最高,为42.05 mg/L;药膜法测得毒死蜱毒力最高,为18.51 mg/L。其中,高效氯氟氰菊酯毒力值变化最大,浸虫法毒力是浸叶法毒力的61.86倍;氯虫苯甲酰胺、氟虫腈在3种生测方法中毒力相当,但均较低。丁硫克百威对暗黑鳃金龟幼虫的毒力最高,LC₅₀值为7.29 mg/L。田间试验结果显示,35%辛硫磷微囊悬浮剂4 500 g/hm²(有效成分,余同)防效达80.66%,对花生的保果、增产幅度分别为77.90%、17.56%;30%毒死蜱微囊悬浮剂2 250 g/hm²、20%丁硫克百威乳油3 000 g/hm²与辛硫磷防效相当,且显著高于其它药剂。因此,选用以上药剂于7月中下旬花生封垄前田间灌墩可以有效减轻暗黑鳃金龟为害。     

Pre- and postnatal exposure to dieldrin: Persistent stimulatory and behavioral effects

Dieldrin was fed to two generations of albino rats at levels often found in the environment (0.35 μg/kg/day, orally). A two-by-two factorial design was employed to investigate the simultaneous effect of a malnutrition condition consisting of low protein and dieldrin exposure. Second generation animals were tested using comprehensive behavioral criteria (swimming ability, righting reflex, motivational test, and a series of learning tasks) in order to detect any subtle diffeences between groups. Significant differences were seen between all of the test groups in the development of swimming ability. Animals in the 10% protein plus dieldrin (10% + D) were significantly inferior to the 10% protein group. However, rats in the 20% protein plus dieldrin (20% + D) were superior to all of the other groups in overall swimming ability. Both dieldrin groups were significantly superior to their control groups in the retention test (running the animals on the same problem 48 hr later), thus suggesting a stimulatory effect of low-dose dieldrin. No implication is made to suggest that the stimulatory effect is not harmful, since the consequences of such effects have not been determined by long-term studies.     

Purification, serology and properties of five zucchini yellow mosaic virus isolates

Five zucchini yellow mosaic virus (ZYMV) isolates designated ZYMV-1, -3, -5, -7 and -FL were purified from zucchini plants grown under the same environmental conditions. Isolates were divided into three groups on the basis of yield of purified virus: group one (ZYM V-5 and -7) yielded 18-24 mg/100 g tissue, group two (ZYMV-3) 5.0-5.7 mg/100 g tissue, and group three (ZYMV-1 and -FL) low yields of 0-5-1-5 mg/100 g tissue. The yield of purified virus was positively correlated with the number of local lesions produced by inoculation of Chenopodium amaranticolor with extracts from infected zucchini leaf tissue. No serological differences were exhibited among the isolates in SDS-immunodiffusion tests. Results of ELISA tests indicated that ZYMV-FL differed from the other isolates and that antiserum to ZYMV-7 absorbed with ZYMV-FL failed to react with ZYMV-FL but retained some serological activity to ZYMV-7 and the other three Taiwanese isolates. The relative molecular masses of capsid proteins for the four ZYMV isolates from Taiwan and ZYMV-FL were similar.