Delayed toxicity after intravenous administration of bioresmethrin to rats

Capillary gas-liquid chromatographic analysis of seven commercial samples of bioresmethrin [5-benzyl-3-furylmethyl (1R)-trans-chrysanthemate] demonstrated that each contained toxicologically significant amounts (1-5%) of the (1R)-cis-isomer (cismethrin) as an impurity. Intravenous injection of the labelled compounds to rats indicated that the concentrated solutions of these compounds may precipitate in the blood and subsequently become trapped in the lung. Slow release of the toxic isomer impurity probably accounts for the delay in appearance of symptoms after intravenous administration of impure bioresmethrin. Similarly, higher doses of cismethrin can be tolerated when concentrated solutions are administered intravenously.     

Pharmacokinetics of sulfluramid and its metabolite desethylsulfluramid after intravenous and intraruminal administration of sulfluramid to sheep

Pharmacokinetic properties and tissue residues of the insecticide sulfluramid (I) and its major metabolite desethylsulfluramid (II) were determined in healthy sheep after bolus intravenous (IV) administration (5 and 15 mg kg⁻¹; n = 10) and bolus intraruminal (IR) administration (100 and 400 mg kg⁻¹; n = 12) of I . Depression, lethargy, and dyspnea were noted for 4 h after the higher IV dose, but not after the other IV or IR doses. The time courses of the mean blood concentrations of I and II were best described by a two-compartment open model with rapid distribution and slow elimination phases. The blood-to-plasma concentration ratios for I and II were 1.43 (± 0.50) and 26.7 (± 9.41), respectively, suggesting binding of II to red blood cells. The T_1/2β values for I and II for the higher IV dose of I were 15.3 (± 4.68) h and 63.4 (± 4.75) h and for the higher IR dose of I , 31.5 (± 5.41) h and 74.9 (± 7.49) h, respectively. Bioavailability was 28.6 (± 2.96)% for the lower IR dose and 19.5 (± 0.99)% for the higher IR dose. C_max values for II were higher in female than male sheep after IR administration of I . Only II was found in tissue samples, with the highest concentration being in liver (9.4 (± 5.2) µg g⁻¹). © 1999 Society of Chemical Industry     

Metabolism of O,O,S-trimethyl phosphorothioate in rats after oral administration of a toxic dose,and the effect of coadministration of its antagonistic thionate isomer

The in vivo metabolism of [¹⁴CH₃S]- and [¹⁴CH₃O]O,O,S-trimethyl phosphorothioate (OOS) was followed in rats after oral administration of threshold or LD₅₀ toxic doses of 20 or 60 mg/kg. Similar metabolic studies were conducted with coadministration of 1% O,O,O-trimethyl phosphorothionate (OOO), which prevented all signs of delayed toxicity, including weight loss. When administered alone, OOS was metabolized mainly (50–60%) via removal of the CH₃S moiety, which was largely converted to expired CO₂. Approximately 20% of the compound was O-demethylated, presumably by conjugation with glutathione, and then further metabolized to CO₂. Major urinary products were identified as O,O-dimethyl phosphoric acid (50–60%) and O,S-dimethyl phosphorothioic acid (～20%). Coadministration of OOO caused a slight decrease (～5%) in the cleavage of the CH₃S moiety, indicated by a reduction in ¹⁴CO₂ from [¹⁴CH₃S]OOS and a quantitatively similar increase in the formation of O,S-dimethyl phosphoric acid. Limited pharmacokinetic studies indicated that OOS was rapidly absorbed and distributed throughout the body. Coadministration of 1% OOO caused a slight increase in the blood half-life of parent OOS when administered at 60 mg/kg. It was concluded that a small proportion of the cleavage of the CH₃S moiety from OOS is involved in the intoxication process, and that this intoxication reaction is specifically inhibited by OOO.     

Tridiphane [2-(3,5-dichlorophenyl)-2-(2,2,2-trichloroethyl)oxirane] an atrazine synergist: Enzymatic conversion to a potent glutathione S-transferase inhibitor

Glutathione S-transferases (GST) from corn, giant foxtail, onion, pea, house fly, and equine liver catalyzed conjugation of tridiphane with glutathione (GSH). The conjugate was characterized by soft ionization mass spectral methods. Tridiphane and the GSH conjugate of tridiphane both inhibited GSH conjugation of atrazine in vitro (corn and giant foxtail). Tridiphane did not inhibit GSH conjugation of 1-chloro-2,4-dinitrobenzene (CDNB) in corn or giant foxtail; however, the GSH conjugate of tridiphane was a competitive inhibitor with respect to GSH and was four times more effective with extracts from giant foxtail (K_i = 2 μM) than from corn (K_i = 8 μM). The GSH conjugate of tridiphane inhibited a variety of GST enzymes with several different substrates. When compared to other inhibitors of GST, only triphenyl tin chloride was more effective than the GSH conjugate of tridiphane in inhibition of GST from giant foxtail. Both GST and GSH decreased in corn and increased in giant foxtail as tissues matured. The catabolism of the GSH conjugate of tridiphane was compared in crude enzyme systems from corn, giant foxtail, and onion. The rate of catabolism was much greater in extracts from corn leaves than from giant foxtail leaves. Inhibition of GSH conjugation of CDNB was reversed as the GSH conjugate of tridiphane was catabolized. The possibility that synergism of atrazine toxicity by tridiphane is mediated by conversion of tridiphane to a GSH conjugate is discussed in relationship to the relative rates of GSH conjugation of tridiphane and atrazine, concentrations of GSH, K_i values, tissue age, and stability of the conjugate in different tissues.     

含1,3,4-噻二唑的吡啶联吡唑乙酰胺类化合物的合成及除草活性

以乙酰丙酮、溴乙酸乙酯和2,6-二氯吡啶为起始原料,经取代、肼基化、环合、水解、酸化及缩合等反应,得到9个未见文献报道的吡啶联吡唑乙酰基类化合物 B1~B9 。其结构均经核磁共振氢谱和质谱表征。初步生物活性测定表明:在150 g/hm2的处理剂量下,大部分目标化合物表现出一定的除草活性,其中化合物 B2、B3、B6 和 B8 对苘麻Abutilon theophrasti Medicus、反枝苋Amaranthus retroflexus和凹头苋Amaranthus lividus L.生长的抑制率接近100%。     

Metabolism of the insecticide SD 8280, 2-chloro-1-(2,4-dichlorophenyl)vinyl dimethyl phosphate,following its application to rice

The metabolism of the insecticide SD 8280 [2-chloro-1-(2,4-dichlorophenyl)vinyl dimethyl phosphate] in rice plants has been examined. When rice seedlings were treated with [¹⁴C]-SD 8280 the major metabolite was 1-(2,4-dichlorophenyl)ethanol which was present mainly conjugated with plant carbohydrates. This compound was also the major metabolite present in grain and straw from rice treated with [¹⁴C]-SD 8280 and grown to maturity under paddy conditions both in the glasshouse and in an outdoor enclosure. Other metabolites detected in the mature plants included 2-chloro-1-(2,4-dichlorophenyl)vinyl methyl hydrogen phosphate and 2,4-dichloro-benzoic acid, both of which occurred in free and conjugated forms. Paddy water was sampled at intervals after the application of [¹⁴C]-SD 8280 and the total residue in the water fell from initial levels of 0.28–1.1 μg/ml (expressed as SD 8280 equivalent) immediately after treatment to <0.01 μg/ml after 2–3 weeks. The total residues in the soil from these experiments were low and did not exceed 0.20 mg/kg (SD 8280 equivalents) through the 0–15 cm profile.     

A new general method of resolving racemic alcohols and its application to (rs)-2-hydroxy-2-(3-phenoxyphenyl)acetonitrile and (rs)-allethrolone

The preparation is described of pure (S)-2-hydroxy-2-(3-phenoxyphenyl)acetonitrile (the alcohol component of some very active pyrethroids) from the racemic form of this 2-hydroxyacetonitrile. The new resolution process is based on differences in physical properties of two diastereoisomeric ethers. The resolving agents used are chiral hemiacetal compounds; one of these, 4-hydroxy-6,6-dimethyl-3-oxabicyclo[3.1.0]hexan-2-one, is available from an industrial synthesis of chrysanthemic acid, and appears specially useful for a two-step resolution of many racemic alcohols, even base-sensitive types.     

Effects of 2-chloroethylphosphonic acid (Ethrel) on gooseberries

Solutions of 2-chloroethylphosphonic acid (Ethrel) up to 480 parts/million concentration were applied as foliar sprays to gooseberries (cv. Careless). Harvesting consisted of shaking the bushes by hand and collecting the dropped fruit. With increasing CEPA level pre-harvest fruit abscission increased and amount of fruit finally left on the bushes decreased. Splitting the application had the effect of reducing pre-harvest abscission. Berry size and total yield were not significantly affected by any of the treatments. Taste-panels did not detect any off-flavours in treated fruit. At hard green fruit stage, analyses for shear value, colour, acidity and soluble solids did not show any marked treatment effects. At ripe fruit stage, softening, yellowing and decrease in acidity were significantly greater for the 480 parts/million CEPA level than for the other treatments. There were no signs of phytotoxic or carry-over effects due to CEPA.     

Persistence,distribution and dislodgeable residues of 2, 4-d following its application to turfgrass

In growth room studies, total recoverable 2, 4-D residues on or in turfgrass (Kentucky bluegrass, Poa pratensis) declined from 92% of that originally applied, to less than 66% by day 15. Although a high proportion of the applied chemical remained associated with the leaf surface under growth room conditions, only 10% was dislodged by vigorous mechanical wiping of the leaf surfaces with moistened cheese-cloth. In field studies with 1 kg acid equivalent (a.e.) ha⁻¹, less than 5% of the chemical originally applied could be dislodged with a cheese-cloth wipe at day 0. Disappearance of dislodgeable residues was very rapid. Less than 0.01% of the applied chemical was dislodgeable after 1 day in turf that received 18 mm of rainfall 1 h after spraying. Residues in turfgrass that received no rainfall required 7 days to dissipate to the same level. In a study in which the clippings were not removed, the disappearance of dislodgeable residues, when the turf was mowed at 3, 7, and 11 days after application, was nearly as rapid as in unmowed turf. In turf treated with 2.24 kg a.e. ha⁻¹ of liquid or granular formulations, dislodgeable residues were less than 1% by days 5 and 3, respectively.     

Preparation of (R)-2-(4-hydroxyphenoxy) propionic acid by biotransformation

With Beauveria bassiana Lu 700 as biocatalyst an ecologically beneficial process has been developed for the production of (R)-2-(4-hydroxyphenoxy) propionic acid. The fungal strain used in this process, B. bassiana Lu 700, is also a very suitable catalyst for the selective monohydroxylation of other aromatic carboxylic acids.     

Foliar residues and toxicity to green leafhoppers of the systemic insecticides aldicarb and its isomer butocarboxim in young peach and plum groves

The isomeric systemic carbamoyloximes aldicarb and butocarboxim were applied at two dose rates to the soil in young peach and plum groves to control the green leafhopper Asymmetrasca decedens Paoli. The effectiveness of the treatments was assessed indirectly by measuring the growth rate of shoots, and by determining the adult mortality of leafhoppers that were collected in the field and kept for 24 h on detached peach leaves in the laboratory. Residues of the insecticides and of their sulphoxide and sulphone metabolites, in the leaves of the peach trees, were determined 18 and 31 days after treatment. Only the sulphoxides and sulphones were found; the sulphoxides amounted to 70–80% of the toxic residues after 18 days, and to 50–70% after 31 days. At an identical rate of application, the leaves from aldicarb-treated peach trees contained higher concentrations of the toxic metabolites and were more toxic to leafhoppers than those of trees treated with butocarboxim.     

Titres of precocene ii (6, 7-dimethoxy-2, 2- dimethylchromene) and its metabolites in the haemolymph of larvae of the african armyworm Spodoptera exempta (walker) following topical treatment with the compound

No precocious metamorphosis or other morphogenetic effects were seen following topical treatment of fifth instar Spodoptera exempta with pre- cocene II. [3H]-Precocene II penetrated the larvae rapidly following topical application. An uptake of 47% was recorded in the first hour and an average of 27% for the first 3 h. Radioactivity in the haemolymph reached a maximum 4 h after treatment at 6–8% of the applied dose. A maximum titre of precocene of 1.1 × 10^?4 _M was observed 2 h after treatment and a biological half-life of around 1 h was recorded for the first 6 h. The metabolite precocene 11–3, 4-dihydrodiol appeared in the haemolymph with a maximum titre of 1.1 × 10^?4 _M at 4 h suggesting metabolism via the 3, 4-epoxide. At the same time an unidentified metabolite was observed possibly corresponding to the 6- and 7-(O)-desmethylated products described by others. Very large quantities of highly polar materials were observed in the haemolymph throughout the experiment and it is thought that these corresponded to conjugates. The evidence suggests that peripheral detoxication mechanisms do not operate sufficiently rapidly to prevent the establishment of a high titre of precocene. This, however, did not affect the corpora allata in this insect, whereas in a sensitive species that has been studied by other workers, necrosis of the glands would have resulted. Alternative explanations for insensitivity are discussed.     

Absorption and translocation of 14C-3,6-dichloropicolinic acid in Cirsium arvense (L.) Scop.

Experiments were conducted in a growth cabinet to investigate the absorption and translocation of ¹⁴C-3, 6-dichloropicolinic acid by Cirsium arvense (L.) Scop. (Canada thistle, creeping thistle), a sensitive species. Applications were made, either to the middle four leaves of 12-cm-tall vegetative plants grown under low (40%) and/or high (>95%) relative humidity (r.h.), or to four upper or lower leaves of 30-cm-tall flowering plants grown under low r.h. Following application to vegetative plants, absorption and translocation of ¹⁴C-3,6-dichloropicolinic acid was rapid and was approximately doubled by high r.h. High r.h. increased the amount of radioactivity retained by the treated leaves or translocated to the shoots but did not affect greatly the amount retained in the roots. The herbicide was highly mobile, with over half of that absorbed, translocated out of the treated leaves after two days. The apex accumulated most of the radioactivity, while approximately 8% was recovered from the roots. The absorption and translocation patterns were similar to those reported in the literature for picloram in C. arvense. Absorption of 3,6-dichloropicolinic acid was greater in vegetative than in flowering C. arvense plants, and placement of herbicide on lower leaves tended to decrease the amount of radioactivity recovered from shoot apex and increase the amount recovered from the roots. Approximately 15% of the applied radioactivity could not be recovered from treated plants by 2 days after treatment.     

Red leaf blotch (Dactuliochaeta glycines) of soybeans (Glycine max) and its relationship to yield

Red leaf blotch of soybeans, caused by Dactuliochaeta glycines, was evaluated on soybean plants in field plots located in Zambia. Two experiments were conducted in each of two seasons. Experiment 1 had four cultivars that were either fungicide-sprayed or not sprayed. Disease severity was greatest on leaves at the lowest nodes from early vegetative through the reproductive growth stages. Area under the disease progress curve (AUDPC) values and percentage of nodes defoliated at growth stage R5 were significantly ( P  = 0.05) greater in unsprayed plots for all cultivars in both seasons. Yield losses ranged from 8 to 37% while reduced seed size ranged from 21 to 29% for the four cultivars. Number of pods per plant in fungicide-sprayed plots did not differ from those in unsprayed plots. However, the number of seeds per plant and seeds per pod were significantly ( P  = 0.05) greater in sprayed than unsprayed plots for some cultivars. In experiment 2, cultivar Tunia was either fungicide-sprayed at different times or not sprayed. The lowest attached leaf had the most variation in the amount of disease while ratings of the most median leaf in the canopy were generally less variable. The AUDPC values calculated from the lowest attached leaf, the mean of all attached leaves, and the median attached leaf differed significantly ( P  = 0.05) the number of times plants were sprayed with fungicide. Defoliation and vertical incidence of red leaf blotch from lower to higher nodes were significantly ( P  = 0.05) reduced in fungicide-sprayed plots in one season, but not the other. One thousand-seed weight and yield differed significantly ( P  = 0.05) with treatment as one application of triphenyltin acetate increased yields by 18% over unsprayed plots in season 1. One thousand-seed weight and yield, regressed on the AUDPC for the median leaf in the canopy, explained 92 and 72% of the variation, respectively.     

黄胸蓟马对香蕉的危害及其防治

１９９６～１９９７年在香蕉花期调查结果表明,黄胸蓟马在广州地区香蕉园中普遍存在,香蕉花感虫率达１００％,平均每花苞感虫８２．８头。感虫数与花苞着生高度有关,以高度１２０～１４０ｃｍ的花苞感虫数最高,以后随高度的增加剧减。黄胸蓟马只危害稍开和已开的第１至第４苞片内花段,且虫口数由外向里递减。园中杂草有助于蓟马对香蕉花的危害,平均每花苞虫口数多杂草蕉园比管理精细的无杂草园多３．６倍。室内药效试验结果表明,毒死蜱、乐果、丁基克百威和灭多威对黄胸蓟马有很好的毒杀效果,氯氰菊酯和顺式氯氰菊酯效果不理想。     

双唑草腈的除草活性及对不同水稻品种和后茬作物的安全性

双唑草腈(pyraclonil)为原卟啉原氧化酶(PPO)抑制剂,为明确其在水稻田的应用前景,采用室内生物测定法研究了双唑草腈的除草活性及对不同水稻品种的安全性,通过大田试验作了进一步验证,并评价了双唑草腈对水稻及后茬作物的安全性。结果表明,双唑草腈对水稻田禾本科杂草稗草、阔叶杂草鸭舌草均有很好的除草活性。在室内试验中,该药剂对稻田稗草和鸭舌草的ED50分别为11.50g/hm~2和8.22g/hm~2,均高于对照药剂丙草胺对稗草和鸭舌草的活性;双唑草腈在3种水稻和稗草之间的选择性指数分别为4.15、3.44和3.73,高于对照药剂;田间试验结果显示,1.8%双唑草腈颗粒剂162、216、324g/hm~2处理在药后20、40d对稗草、鸭舌草、节节菜及异型莎草的株防效均在98%以上,显著优于对照药剂80%丙炔噁草酮可湿性粉剂和50%丙草胺乳油;双唑草腈对水稻以及三种主要后茬作物小麦、油菜和小白菜安全。研究表明双唑草腈具有很好的应用前景。     

Toxico‐kinetics,recovery efficiency and microsomal changes following administration of deltamethrin to black Bengal goats

A study of the toxico‐kinetics, recovery percentage from different substrates, cytotoxicity and role of cytochrome P₄₅₀ and b₅ of liver microsome in the metabolism of deltamethrin were carried out in female black Bengal goat. The ALD₅₀ value of deltamethrin in goat by intravenous route lies between 0.2 and 0.6 mg kg^?1. Intravenous disposition kinetics using a dose of 0.2 mg kg^?1 showed that the maximum blood concentration of deltamethrin was recorded at 0.5 min, followed by rapid decline, and a minimum concentration was detected at 6 min after administration. The following values were obtained : Vd_area 0.148 (± 0.02) litre kg^?1; t_1/2 (α) 0.22 (± 0.02) min; t_1/2 (β) 2.17 (± 0.37) min; K_el 1.05 (± 0.24) min^?1; AUC 4.30(± 0.45) µg min ml^?1; Cl_B 0.05 (± 0.006) litre kg^?1 min^?1; T～B 1.93 (± 0.58); fc 0.40(± 0.05). After 10 min, liver retained the maximum residue, and heart, adrenal gland, kidney, spleen, fat and brain also held the insecticide; liver, fat, heart and spleen retained residue after 30 min, and bone, liver and fat retained residue after 60 min of intravenous administration. Oral absorption of deltamethrin was poor and inconsistent, and approximately 65% of administered dose was recovered from faeces and gastrointestinal contents. The excretion of deltamethrin through urine was meagre, and only 0.01 and 0.013% of the administered dose was recovered after 3 and 5 days of oral administration respectively. All the tissues retained the residue after 3 days; while fat, rumen, reticulum, omasum, abomasum, large and small intestine and bone retained the residue after 5 days of oral administration; and the percentage recoveries were 1.73 and 0.027 respectively. Deltamethrin reduced the level of cytochrome P₄₅₀ content of liver microsomal pellet of goat after 5 days of oral administration. Histopathological examination of liver, kidney, heart, spleen brain and lung sections of treated goats did not reveal any pathological changes. © 2001 Society of Chemical Industry     

2-(溴代吡咯腈-1-基)乙酸衍生物的设计、合成及生物活性

为了发现具有生物活性的新化合物,以溴代吡咯腈为先导化合物,通过亲核取代等反应合成了一系列新型2-(溴代吡咯腈-1-基)乙酸衍生物(5a～5m, 6a～6o),其结构均经核磁共振氢谱(¹H NMR)、碳谱(¹³C NMR)和高分辨质谱(HRMS)确证。杀菌活性测定结果显示：化合物2、3和5m对水稻稻瘟病菌Magnaporthe oryzae均表现出良好的杀菌活性,其EC₅₀值分别为0.0532、0.0470和0.0174 mmol/L,优于对照药剂咯菌腈(0.0914 mmol/L),但不及对照药剂嘧菌酯(0.0001 mmol/L);化合物5m表现出一定的杀菌广谱性,其对水稻纹枯病菌Rhizoctonia solani和小麦根腐病菌Bipolaris sorokiniana的EC₅₀值分别为0.0218和0.0420 mmol/L,但均不及对照药剂咯菌腈(EC₅₀值分别为0.0002和0.0010 mmol/L)。杀虫、杀螨活性测定结果显示,在0.2 mmol/L浓度下,目标化...