Sulfur in pesticide action and metabolism: Edited by J. D. Rosen,P. S. Magee,and J. E. Casida,American Chemical Society,Washington, D.C., 1981. 172 pp., $33.00

The distribution of ¹⁴C-acid-, ¹⁴C-alcohol-, and ¹⁴C-cyano-labeled deltamethrin and selected metabolites were followed in the liver, blood, cerebrum, cerebellum, and spinal cord after iv administration of a toxic, but nonlethal dose (1.75 mg/kg) to rats. Approximately 50% of the dose was cleared from the blood within 0.7–0.8 min, after which the rate of clearance decreased. 3-Phenoxybenzoic acid (PBacid) was isolated from the blood in vivo, and was also the major metabolite when ¹⁴C-alcohol-labeled deltamethrin was incubated with blood in vitro. Deltamethrin levels in the liver peaked at 7–10 nmol/g at 5 min and then decreased to 1 nmol/g by 30 min. In contrast, peak central nervous system levels of deltamethrin were achieved within 1 min (0.5 nmol/g), decreasing to 0.2 nmol/g at 15 min, and remaining stable until 60 min. peak levels of deltamethrin did not correspond to the severity of toxicity, although the levels of non-pentane-soluble radiolabel did appear to correlate with motor signs of toxicity. Experiments with brain homogenates, using in vivo concentrations of deltamethrin, failed to reproduce the pentane-unextractable radioactivity in vitro nor was any metabolism demonstrated.     

Action of cismethrin and deltamethrin on functional attributes of isolated presynaptic nerve terminals from rat brain

Isolated presynaptic nerve terminals (synaptosomes) prepared from rat brain were used to evaluate the actions of a tremor (T)-syndrome (cismethrin) and a choreoathetosis-salivation (CS)-syndrome (deltamethrin) pyrethroid on the functional attributes of synaptosomes by measuring calcium influx and endogenous neurotransmitter (l-glutamate) release with fluorescent assays. Both cismethrin and deltamethrin stimulated calcium influx, however, only deltamethrin enhanced Ca²⁺-dependent neurotransmitter release and its action was stereospecific, concentration-dependent, stimulated by depolarization, unaltered by tetrodotoxin, and blocked by ω-conotoxin GVIA. Our results delineate a separate action of deltamethrin on presynaptic nerve terminals from that elicited by cismethrin and implicate Ca_v2.2 calcium channels as target sites for deltamethrin that is consistent with the observed in vivo release of neurotransmitter at the onset of convulsive symptom caused by CS-syndrome pyrethroids. This information will allow a more complete understanding of the molecular and cellular nature of pyrethroid-induced neurotoxicity and expands our knowledge of the structure–activity relationships of pyrethroids in regards to their action on voltage-sensitive calcium channels.     

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     

Binary mixtures of pyrethroids produce differential effects on Ca influx and glutamate release at isolated presynaptic nerve terminals from rat brain

Isolated rat brain synaptosomes were used to evaluate the action of pyrethroid mixtures on Ca²⁺ influx and subsequent glutamate release under depolarizing conditions. In equipotent binary mixtures at their respective and/or estimated EC₅₀s with deltamethrin always as one of the two components, cismethrin, λ-cyhalothrin, cypermethrin, esfenvalerate and permethrin were additive and S-bioallethrin, fenpropathrin and tefluthrin were less-than-additive on Ca²⁺ influx. In binary mixtures with deltamethrin always as one of the two components, esfenvalerate, permethrin and tefluthrin were additive and λ-cyhalothrin was less-than-additive on glutamate release. Binary mixture of S-bioallethrin and cismethrin was additive for both Ca²⁺ influx and glutamate release. Only a subset of pyrethroids (S-bioallethrin, cismethrin, cypermethrin, and fenpropathrin) in binary mixtures with deltamethrin caused a more-than-additive effect on glutamate release. These binary mixtures were, however, only additive (cismethrin and cypermethrin) or less-than-additive (S-bioallethrin and fenpropathrin) on Ca²⁺ influx. Therefore, increased glutamate release evoked by this subset of pyrethroids in binary mixture with deltamethrin is not entirely occurring by Ca²⁺-dependent mechanisms via their action at voltage-sensitive calcium channels. These results suggest that pyrethroids do not share a common mode of toxicity at presynaptic nerve terminals from rat brain and appear to affect multiple target sites, including voltage-sensitive calcium, chloride and sodium channels.     

Time-dependent changes in protein phosphorylation patterns in rat brain synaptosomes caused by deltamethrin

Effects of deltamethrin, a powerful pyrethroid insecticide, on the protein phosphorylation and dephosphorylation processes during depolarization in rat brain synaptosomes were studied by using [³²P]phosphoric acid as a starting radiotracer and high external concentration of potassium ions or veratridine (10^?-5 M) as depolarizing agents. At the onset of depolarization there was a quick rise in phosphorylation in various synaptic proteins for about 15–30 s followed by a gradual decline in levels of phosphorylation. The effect of deltamethrin (10^?-7 M) on this system was found to be dependent on the length of preincubation of the synaptosome with the pesticide prior to depolarization. At an early stage (0–3 min preincubation period) it caused a modest suppression of protein phosphorylation activities. When the period of deltamethrin preincubation was extended to 5–20 min, however, it caused a significant increase in protein phosphorylation throughout the depolarization period. At the later stage of the action of deltamethrin (e.g. preincubation period of 30–40 min), deltamethrin-treated synaptosomes no longer responded to the depolarization signal to raise the level of phosphorylation on many proteins. These results indicate that deltamethrin's actions on the synaptic process are complex. Depending on the length of exposure, its effects on protein phosphorylation responses in intact synaptosomes could be either stimulatory or inhibitory. To study the cause of deltamethrin-induced synaptic block at the later stage, effects of deltamethrin on protein kinases were studied by using lysed synaptic membranes with [gamma-³²P]ATP. Deltamethrin was shown to inhibit calcium–calmodulin-dependent protein phosphorylation activities at 10^?-7 M when given directly to the enzyme source 10 min prior to the addition of [³²P]ATP. Such an observation helps to explain the inhibitory action of deltamethrin on protein phosphorylation which occurs at the late stage of its action (i.e. preincubation time > 20 min).     

Effects of some nonionic polyoxyethylene surfactants on uptake of ethirimol and diclobutrazol from suspension formulations applied to wheat leaves

The influence of a number of commercial nonionic polyoxyethylene surfactants on the foliar penetration and movement of two systemic fungicides, ethirimol and diclobutrazol, was studied in outdoor-grown wheat plants at different growth stages and post-treatment temperatures in two consecutive growing seasons. Both fungicides were applied as ca 0·2 μl droplets of aqueous suspension formulations containing 0·5 g litre^?1 of ¹⁴C-labelled active ingredient; surfactants were added to these suspensions at concentrations ranging from 0·2-10 g litre^?1. To achieve optimum uptake of each fungicide the use of surfactants with different physicochemical properties was required. For diclobutrazol, a lipophilic compound, uptake of radiolabel was best with surfactants of low mean molar ethylene oxide (E) content (5-6) but it was necessary to use concentrations of ca 5 g litre^?1 to attain this. The surfactant threshold concentration for uptake enhancement of radiolabel from ethirimol formulations (< 2 g litre^?1) was much lower than that for diclobutrazol but surfactants with E contents > 10 induced the greatest amount of uptake. For both fungicides, surfactants with an aliphatic alcohol hydrophobe were generally more efficient in promoting their uptake than those with a nonylphenol moiety. The sorbitan-based surfactant ‘Tween 20’ proved to be an effective adjuvant only for the ethirimol formulation; the uptake enhancing properties of the block copolymer ‘Synperonic PE/F68’ were weak. Uptake performance could not be related to the spreading properties of the respective formulations on the wheat leaf surface or to differences in solubilisation of the two fungicides by the surfactants. Although surfactants could substantially increase the amount of acropetal transport of radiolabel from both fungicides, none of those tested specifically promoted it; a constant proportion of the radioactive dose absorbed by a treated leaf was usually exported away from the site of application. The results are discussed in the light of current theories about the mode of action of surfactants as spray adjuvants.     

The relationship between the pharmacokinetics of intravenous cismethrin and bioresmethrin and their mammalian toxicity

The distribution and excretion of [¹⁴C]alcohol-labeled cismethrin and bioresmethrin was determined after intravenous administration to rats. Initially the label distribution of both isomers was similar, but differences occurred at later times mainly due to the retention of 5-benzyl-3-furylcarboxylic acid, a metabolite of bioresmethrin, in high concentration in the blood. Retention of this metabolite accounted for the slower excretion of bioresmethrin label compared to cismethrin. After administration of either isomer, parent pyrethroid was rapidly cleared from the blood and liver, and both isomers rapidly entered the central nervous system reaching peak concentrations within 2–5 min. Brain cismethrin concentrations exceeding 3.5 nmol/g were associated only with animals showing tremors. These levels of cismethrin are maintained for up to 30 min but bioresmethrin was depleted more rapidly possibly due to brain metabolism. It is concluded that the low toxicity of bioresmethrin is possibly due to the inability of this isomer to interact with the site of action in the central nervous system and not, as previously suggested, primarily because of more rapid metabolism in the liver.     

The elimination of (N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide) by the boll weevil

Boll weevils, Anthonomus grandis Boheman, were either dipped in or injected with a solution of [¹⁴C]diflubenzuron (N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide) or fed on cotton squares that had been treated with the chemical to determine its turnover time and metabolic fate. No significant differences were observed between male and female weevils in their ability to eliminate [¹⁴C]diflubenzuron. Only minor differences were observed when immersion and injection treatments were compared. When weevils were treated with 66.3 ng of [¹⁴C]deflubenzuron per weevil by injection, the insects contained 13 to 15% of the radiolabel after 6 days and 4 to 6% after 13 days. The remainder of the radiolabel was in the frass. When weevils fed for 66 hr on cotton squares that had been treated with a wettable [¹⁴C]diflubenzuron preparation (Dimilin W-25), the insects averaged 120 ng of diflubenzuron per weevil. Forty-four hours after removing insects from the treated squares, 50% of the radiolabel had been excreted. In all cases, the radiolabel found in the frass or in the weevil was unchanged diflubenzuron. There were no data to indicate that the boll weevil could metabolize appreciable amounts of diflubenzuron.     

Action of deltamethrin on N-type (Cav2.2) voltage-sensitive calcium channels in rat brain

Isolated presynaptic nerve terminals prepared from whole rat brain were used to evaluate the action of deltamethrin on voltage-sensitive calcium channels by measuring calcium influx and endogenous glutamate release. Deltamethrin-enhanced K⁺-stimulated calcium influx and subsequent Ca²⁺-dependent glutamate release. The effect of deltamethrin was concentration-dependent, stereospecific, blocked by ω-conotoxin MVIIC but unaltered in the presence of tetrodotoxin. These results suggest that N-type voltage-sensitive calcium channels are a site of action at the presynaptic nerve terminal. Electrophysiological studies were carried out using rat brain Ca_v2.2 and β₃ subunits coexpressed in Xenopus oocytes to validate such action. Deltamethrin reduced barium peak current in a concentraion-dependent and stereospecific manner, increased the rate of activation, and prolonged the inactivation rate of this channel. These experiments support the conclusion that N-type voltage-sensitive calcium channel operation is altered by deltamethrin.     

Action of deltamethrin on the calcium/calmodulin-dependent protein kinase from the rat brain

The action of deltamethrin on the calcium/calmodulin-dependent protein kinase (CaM-Kinase II) and phosphatase system in the rat brain synapse was studied under various experimental conditions to optimize these enzyme activities and to facilitate the studies of the mechanism of interaction of this pesticide with several components of this enzyme system. To obtain a clear-cut inhibition of this enzyme by deltamethrin the following conditions must be met: (a) the enzyme system should be purified by precipitation with ammonium sulfate (450 g litre^?1) prior to the addition of deltamethrin, (b) both Ca²⁺ and calmodulin (CaM) should be added to the incubated media before the addition of [y-³²P]ATP, (c) deltamethrin should be incubated at least 10 min (but less than 30 min) with the enzyme system before [y-³²P]ATP addition, (d) the incubation temperature should be above 20°C (optimum 30°C), (e) [y-³²P]ATP concentration should be in the order of 10^? M (concentration adjusted using cold ATP), and (f) the incubation time with [y^?P]ATP for incorporation of ³²P into the protein should be in the neighborhood of 60 s. Under these conditions, the inhibitory potency of various active and inactive isomers or analogs of pyrethroids and DDT was tested. The order of the inhibitory power of these active forms of pesticides was 1 R-deltamethrin > (S)(RS) fenvalerate ≥ p,p′-DDT. Other compounds were not active at the concentration tested, indicating the differential sensitivity of this enzyme and the existence of a correlation of inhibitory power to insecticidal activity.     

Studies on the effect of deltamethrin sprays on the numbers of epigeal predatory arthropods occurring in arable fields

The effect of spraying winter rape and winter wheat with deltamethrin on the numbers of epigeal Carabidae, Staphylinidae and Linyphiidae caught in pitfall traps was studied in Northern Germany in 1980 and 1981. Two experiments were performed with each crop, deltamethrin being sprayed at 7.5 g a.i. ha^?1 in 300 litres of water in springtime on rape, and in midsummer on wheat. Sprayed plots were rectangles of 2 and 3 ha; unsprayed plots were squares of 0.5 ha each (two replicates). Ten pitfall traps were placed per replicate at least 3 weeks before spraying and were left for at least 3 weeks after spraying, the traps being emptied weekly. Beneficial Carabid species which have been shown already to have an economic significance, were rare during this study, but four other species (three of them were autumn breeders) were not affected by deltamethrin. At the spraying dates the autumn breeders were hidden in the soil as pupae. Three Staphylinid species, studied in only one experiment each, appeared to be strongly reduced in numbers by deltamethrin. The Linyphiid spiders were affected most heavily by deltamethrin sprayed in spring or in midsummer; the initial mortality of more than 92% lasted longer than 4 weeks, and an adverse effect was still significant in winter wheat 6 weeks after spraying. Overall, deltamethrin appears to have a broad spectrum effect concerning the epigeal predatory arthropods.     

Pyrethroid insecticides: Potent,stereospecific enhancers of mouse brain sodium channel activation

Deltamethrin and NRDC 157, pyrethroid insecticides that produce different poisoning syndromes in mammals, enhanced veratridine-dependent, sodium channel-mediated ²²Na⁺ uptake in mouse brain synaptosomes. Concentrations producing half-maximal enhancement were 2.5 × 10^?8M (deltamethrin) and 2.2 × 10^?7M (NRDC 157). This effect was stereospecific: The nontoxic 1S enantiomers had no significant effect on veratridine-dependent activation. At high deltamethrin concentrations, enhancement was maximal at 5 × 10^?5?1 × 10^?4M veratridine. Pyrethroid enhancement was completely blocked by 5 × 10^?6M tetrodotoxin, and neither pyrethroid affected ²²Na⁺ uptake in the absence of veratridine at concentrations up to 1 × 10^?5M. The relative potencies of deltamethrin and NRDC 157 in the synaptosomal sodium channel assay agree well with their relative acute toxicities to mice when administered by intracerebral injection. These findings demonstrate that pyrethroids exemplifying both characteristic poisoning syndromes are potent, stereospecific modifiers of sodium channel function in mammalian brain.     

Effects of deltamethrin and its commercial formulation DECIS on different cell types in vitro: Cytotoxicity,cellular binding,and intracellular localization

To investigate the effect of deltamethrin and other pyrethroids on nonexcitable cells, we tested these molecules on animal (fibroblasts) and plant (algae) cells in culture. The effects of pyrethroids on cellular proliferation vary according to their structure. Deltamethrin (from 5 × 10⁻⁵ M) affected the growth of fibroblasts, but was inactive on other cells. Commercial formulations (DECIS EC and DECIS FLO) were more active to cells, but this effect was due mostly to the matrix. However, these matrices facilitated the penetration of deltamethrin into cells. Studies of [³H]deltamethrin uptake indicated the labeling of macromolecules, but labeling was reduced significantly after treatment with organic solvents. Autoradiographic studies with [³H]deltamethrin showed labeling of cells at the cytpolasmic level.     

Deltamethrin induced alterations of hematological and biochemical parameters in fingerlings of Catla catla (Ham.) and their amelioration by dietary supplement of vitamin C

The present study was carried out to investigate the sub-lethal toxicity of technical grade deltamethrin (a synthetic pyrethroid) of concentration 1.61 μg/L (1/3rd of 96 h LC₅₀) on hematological and biochemical parameters of catla (Catla catla) fingerlings and its amelioration through dietary vitamin C. The deltamethrin exposed fishes were fed with different levels of supplemented vitamin C such as 50, 250, 500 and 1000 mg/kg diet to see its ameliorating effect by assaying hematological parameters viz. total erythrocyte count (TEC), total leukocyte count (TLC), hemoglobin content (Hb), total serum protein, albumin, globulin, albumin–globulin ratio and biochemical parameters such as lactate dehydrogenase (LDH), acetylcholine esterase (AChE), alanine amino transferase (ALT), aspartate amino transferase (AST), total adenosine triphosphatase (ATPase), magnesium adenosine triphosphatase (Mg²⁺-ATPase) and sodium potassium adenosine triphosphatase (Na⁺, K⁺-ATPase) activities. The finding of this study showed that deltamethrin had negative effect on the hematological and biochemical parameters of Catla catla. The experimental group, which was exposed to deltamethrin and fed with normal diet showed significantly lower values (P ? 0.05) of all parameters studied except ALT activity. This might be due to possible disruption of hematopoiesis and proteosynthesis. However, the fish fed with varied concentration of vitamin C in diets neutralized the toxic effect of deltamethrin, as evidenced by significantly lowered hematological and biochemical response. Vitamin C @ 1000 mg/kg diet was the most effective in amelioration of harmful effect of deltamethrin on hematological and biochemical parameters of catla fingerlings. The result suggests that vitamin C can be effectively used to neutralize the toxic effect of deltamethrin on catla.     

Fate and persistence of residues on wheat used to explain efficacy differences between deltamethrin suspension concentrate and emulsifiable concentrate formulations

To help explain the increased residual activity of a deltamethrin suspension concentrate (SC) formulation against grasshoppers, the persistence, location and nature of residues from the SC and an emulsifiable concentrate (EC) formulation have been compared. Wheat plants were sprayed in a cabinet sprayer at 7.6 g ha^?1 for the EC and 5.6 g ha^?1 for the SC, then weathered outdoors for 16 days. With the SC formulation, residues were more persistent, more residues were located on the exterior of the leaves, and less deltamethrin was converted to inactive isomers. Eight days after spraying, the exterior deltamethrin residues were 0.13 μg plant^?1 from the SC versus 0.06 μg plant^?1 from the EC. Thus, more residual deltamethrin is available to grasshoppers with the SC formulation.     

Alfalfa metabolism of propham

Root-treated alfalfa absorbs, translocates, and metabolizes [phenyl-¹⁴C]isopropyl carbanilate ([¹⁴C]propham). After 7 days of root treatment, the distribution of radiolabel was 73% for shoots and 27% for roots. Shoots and roots were extracted and separated into the polar, nonpolar, and solid residual components using a mixture of chloroform, methanol and water. The insoluble residues accounted for approximately 40% of the ¹⁴C found in shoots and roots. The nonpolar fraction (6.1% of the radiolabel in shoots and roots) was not characterized, but was shown to be some component other than parent propham. Propham was not found in either shoots or roots. The polar metabolites were partly purified on Amberlite XAD-2. Cellulase-liberated aglycones were derivatized and separated by high-performance liquid and gas-liquid chromatography. The infrared, nuclear magnetic resonance, and mass spectral data showed that the polar metabolites of alfalfa shoots and roots were glycoside conjugates of isopropyl 2-hydroxycarbanilate (2-hydroxypropham) and isopropyl 4-hydroxycarbanilate (4-hydroxypropham). Conjugated 4-hydroxypropham accounted for 45.9% of the ¹⁴C in the shoots and 3.4% of the ¹⁴C in the roots. Conjugated 2-hydroxypropham accounted for 3.4% of the ¹⁴C in the shoots and 1.4% of the ¹⁴C in the roots.     

Enhancement of neurotransmitter release from invertebrate synaptosomes by pyrethroids during pulsed-depolarization: A functional assay for effects on repolarization

The release of [³H]neurotransmitters was used as a functional assay to assess the actions of selected neurotoxins on the synaptosomal membranes prepared from the invertebrate nervous systems of squid and house fly. A reproducible release of [³]neurotransmitter was evoked by pulsed-depolarization in the presence of elevated K⁺ or of veratridine. Pretreatment with deltamethrin resulted in a substantial enhancement of [³H]neuro-transmitter release during pulsed-depolarization. This enhanced neurotransmitter release was greatly reduced or absent when synaptosomes of knockdown-resistant house flies were examined. No enhanced neurotransmitter release due to deltamethrin pretreatment was apparent from any synaptosomal preparation under non-depolarizing conditions. Under similar conditions, collaborative experiments demonstrated that deltamethrin causes a significant change in protein phosphorylation activities which follow depolarization. The most significant change caused by deltamethrin was the prolonged elevation of the level of phosphorylation on a number of key synaptic proteins beyond the normal time of their recovery to the dephosphorylated state. The most notable protein reacting to deltamethrin in this manner was calcium-cadlmodulin-dependent protein kinase.     

Mutation of threonine 422 to glutamic acid mimics the phosphorylation state and alters the action of deltamethrin on Cav2.2

Effects of deltamethrin on voltage-sensitive calcium channels (VSCC) from rat brain (Ca_v2.2) expressed in Xenopus oocytes were assessed electrophysiologically. Deltamethrin reduced peak current of wild-type Ca_v2.2 in a stereospecific and concentration-dependent manner with an EC₅₀ of 1 × 10⁻⁹ M. Phosphorylation of threonine 422 enhances voltage-sensitive calcium current, increases the probability that Ca_v2.2 will open under depolarizing conditions and antagonizes the inhibition of the channel by the betagamma subunit of heterotrimeric G-protein (Gβγ). Site-directed mutagenesis of threonine 422 to glutamic acid (T422E) results in a channel that acts as if it were permanently phosphorylated. Deltamethrin (10⁻⁷ M) significantly enhanced peak current via the T422E channel (1.5-fold) compared to the nontreated control and the increase was significantly greater than for either the wild-type (T422) or T422A (permanently unphosphorylated mutant) channels. The effect of deltamethrin on T422E Ca_v2.2 was stereospecific and concentration-dependent with an EC₅₀ of 9.8 × 10⁻¹¹ M. Thus, Ca_v2.2 is modified by deltamethrin but the resulting perturbation is dependent upon the phosphorylation state of threonine 422.     

直接竞争酶联免疫吸附分析法测定小白菜中溴氰菊酯的残留量

应用作者所在实验室自制的、对溴氰菊酯具有特异性亲和力的多克隆抗体和酶标半抗原,建立了包被抗体-酶标半抗原直接竞争酶联免疫吸附分析法(DC-ELISA)。小白菜样品经超声提取、浓缩和10%甲醇定容后采用DC-ELISA法测定,并采用高效液相色谱法进行验证。结果表明:在抗体包被浓度为2.0 mg/L、辣根过氧化物酶(HRP)标记溴氰菊酯半抗原稀释2.0×105倍、包被介质为pH 7.2 PB、反应介质为含0.125 mol/L NaCl pH 6.8 PB的优化条件下,DC-ELISA法检测溴氰菊酯的线性范围为0.10~10 mg/L,溴氰菊酯对抗体-酶标半抗原反应的抑制中浓度(IC50)为1.68 mg/L,相对标准偏差(RSD,n=5)为2.11%,IC10值为0.16 mg/L。在5、1和0.2 mg/kg 3个添加水平下,DC-ELISA法测定小白菜中溴氰菊酯的平均回收率分别为97%、106%和95%,RSD(n=5)分别为8.5%、8.1%和8.1%。高效液相色谱法同步测定小白菜中添加0.2 mg/kg溴氰菊酯的回收率为107%。本研究建立的DC-ELISA法可用于小白菜中溴氰菊酯含量的快速测定。     

近红外光谱法快速测定农药中溴氰菊酯含量

用近红外(NIR)光谱技术结合偏最小二乘法(PLS)进行了敌杀死乳油中有效成分溴氰菊酯含量的快速检测。通过比较敌杀死乳油与常用溶剂的近红外光谱,确定了乳油中使用的溶剂为二甲苯。在敌杀死乳油中加入二甲苯或溴氰菊酯原药来配制不同浓度的校正集,采用PLS建立了有效成分溴氰菊酯的分析模型,模型的决定系数R2、校正标准差(SEC)、交互验证参差均方根(RMSECV)值分别为0.999 9,0.013和0.022。结果表明:近红外光谱技术可以准确测定商品农药制剂中有效成分含量,方法简便、快速,适用于溴氰菊酯制剂的现场、在线分析。