Immunotoxicity of aminocarb : I. Comparative studies of sublethal exposure to aminocarb and dieldrin in mice

Immunotoxicity of a carbamate pesticide, aminocarb (Matacil), introduced orally in sublethal doses to C57B1/6 inbred mice, has been compared to the immunosupressive effects of the organochlorine pesticide, dieldrin (served as a positive control), in bacterial and viral infections. In vivo infection of pesticide-exposed mice with Salmonella typhimurium and mouse hepatitis virus 3 (MHV3) showed that two subsequent LD₅₀ doses of aminocarb did not decrease the resistance of animals to the pathogens, whereas exposure to dieldrin resulted in augmented mortality. In vitro studies showed that the spread of MHV3 virus infection and virus-induced cytopathic effects (cpe) were augmented in peritoneal macrophages after exposure to aminocarb, albeit to a much less extent than in the dieldrin group. Similarly, a decrease in the anti-MHV3 IgM serum antibody titer by aminocarb was less marked than in the dieldrin group. Alternatively, immunization of animals with a neutral antigen, sheep red blood cells (SRBC), showed a significant increase in the anti-SRBC humoral response 10 days after a single oral exposure to LD₅₀ aminocarb. The cellular immune response, determined by mixed lymphocyte reaction, was unaffected by sublethal aminocarb exposure. In addition, macrophage antigen processing of a single protein, avidin, was unaffected by aminocarb, contrary to the inhibition of avidin processing in macrophages from dieldrin-gavaged mice. The data do not indicate that immunotoxic properties are associated with aminocarb, and only slight effects with high sublethal doses of orally given aminocarb on macrophage susceptibility to the MHV3 viral pathogen were observed at a terminal phase of the disease.     

乙草胺人工抗原的合成及其单克隆抗体的制备

通过乙草胺与3-巯基丙酸在碱性条件下反应合成了半抗原——乙草胺-巯基丙酸(AMPA)。采用活性酯法将半抗原AMPA分别与牛血清白蛋白(BSA)和卵清蛋白(OVA)偶联制备了人工抗原。通过紫外光谱测定了AMPA与BSA及OVA间的分子结合比分别为41和26。用AMPA-BSA免疫小鼠,制备得到的单克隆抗体的效价为1∶ 16×104。以AMPA-OVA作包被抗原,用乙草胺单克隆抗体建立了ELISA检测方法,IC50值为0.55 μg/L,方法的检测范围为0.04~5 μg/L,检测限为0.04 μg/L。     

Humoral intestinal immunity against Encephalitozoon cuniculi (Microsporidia) infection in mice

Three strains of mice, BALB/c, IL-12 knock-out (KO) and INF-gamma knock-out, were chosen as an experimental model for the study of intestinal immunity induction against Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 infection. Mice were infected perorally with 10(7) spores and re-infected with the same dose 70 days after the first infection. The anti-E. cuniculi IgA, IgG and IgM responses in sera and extracts of stool samples were determined by ELISA. Results have shown specific antibody production in the sera and intestinal secretions of all three strains of mice induced orally by E. ciniculi spores. BALB/c mice developed a stronger humoral immune response than IL-12 KO mice. The lowest antibody response developed in INF-gamma KO mice that succumbed to the infection within 28 days post infection.     

The concentration of pesticides in sediments from Kolleru Lake in India

Kolleru Lake is the largest natural freshwater lake in India. Sediment samples were collected at different locations from Kolleru Lake at different seasons in a year over a period of three years and analyzed for eight selected pesticides. In general, pesticides were present at all locations. The selected pesticides alpha-BHC, gamma-BHC, malathion, chlorpyrifos and endosulfan were present at higher concentrations than isodrin, dieldrin and p,p'-DDT. The concentrations of alpha-BHC, gamma-BHC malathion, chlorpyrifos, isodrin, endosulfan, dieldrin and p,p'-DDT in sediments were 1.2-388, 1.4-212, from below the minimum detection limit (BDL)-186, 1.1-292, BDL-38.6, BDL-206, BDL-128 and BDL-191 micrograms kg-1 dry weight, respectively. The aim of this study is to evaluate baseline data, to try to account for the concentration of pesticides in sediments and to discuss their potential to affect human beings and aquatic organisms.     

水中12 种农药的固相萃取及GC-MS 测定方法研究

利用气相色谱法进行测定 ,用己烷和丙酮做洗脱溶剂 ,用 Isolute TMENV+SPE柱对水中 12种农药的固相萃取方法进行了研究 ,并用 MS选择离子模式进行了定量分析。水中添加浓度为 1、5、10μg· L-1三个水平 ,其中 11种农药的添加回收率在 6 2 .3%～ 10 5.0 % ,只有克百威的回收率较低。     

Monoclonal antibody for the detection and identification of a phytoplasma associated with rice yellow dwarf

One stable hybridoma clone, 247B11, secreting specific monoclonal antibody (MA) against the mycoplasmalike organism (MLO), newly be termed phytoplasma, associated with rice yellow dwarf (RYD) was produced by employing an immunization scheme for inducing the immunological tolerance of mice to rice antigens prior to the administration of RYD-phytoplasma immunogens. Neonatal BALB/c mice were first injected with nontarget rice antigens present in the immunogen preparation and were immunized intrasplenically with RYD-phytoplasmaenriched antigens prepared by Percoll density-gradient fraction 6 wk later. The MA was of the IgG1 class. With this MA, RYD-phytoplasma in diseased rice was specifically detected by indirect enzyme-linked immunosorbent assay (ELISA), immunofluorescent staining and tissue-blotting techniques. Antibody titer determined by indirect ELISA for hybridoma-culture supernatant was 5120. The antibody recognized two polypeptides, 16 kDa and 41 kDa of RYD-phytoplasma determined by western blotting. RYD-phytoplasma was differentiated serologically from the phytoplasmas associated with sweetpotato, peanut, loofah, paulownia, andIpomoea obscura witches' broom, aster yellows (NJ strain), elm yellows, and sugarcane white leaf both in indirect ELISA and immunofluorescent staining.     

Activity of Soil Insecticides on Eggs of Diabrotica undecimpunctata howardi: Effects on Embryological Development and Influence of Egg Age

The activity of tefluthrin, carbofuran, terbufos and dieldrin in soil against eggs of different ages of the southern corn rootworm, Diabrotica undecimpunctata howardi (Barber) (Coleoptera: Chrysomelidae) was determined. Embryological development following treatment with these insecticides was also investigated to determine the stage of developmental arrest. Generally, younger eggs were found to be more susceptible, dieldrin being the least and tefluthrin the most potent ovicide of combined egg age mortalities. Terbufos and carbofuran were relatively inactive against older eggs compared with tefluthrin. Terbufos stopped embryonic development at the time when acetylcholine esterase activity has been shown to commence. Carbofuran, dieldrin and tefluthrin slowed but did not arrest embryonic development, although the two former compounds prevented eclosion to a greater degree than tefluthrin, suggesting death during absorption of serosal fluids at eclosion. Neonate emergence following treatment of eggs with tefluthrin resulted in death within a few hours. The results are discussed in relation to insecticidal action and permeability changes of egg membrane structure with age. © 1997 SCI.     

Action of pesticides on earthworms. Part I: The toxicity of cholinesterase-inhibiting insecticides to earthworms as evaluated by laboratory tests

The action of seven cholinesterase-inhibiting pesticides [aldicarb, carbaryl, carbofuran, oxamyl, paraoxon (diethyl 4-nitrophenyl phosphate) parathion and trichloronate], the organochlorine insecticide, gamma-HCH, and the nematicide potassium N-hydroxymethyl-N-methyl(dithiocarbamate) (PHMD) on four earthworm species was investigated by laboratory toxicity tests. Eisenia foetida was the most tolerant species to the pesticides tested. Aldicarb was the most toxic pesticide to this species, causing severe dehydration prior to death or at sublethal concentrations. Aldicarb was also toxic to the other species (Allolobophora caliginosa, A. chlorotica and Lumbricus rubellus), while oxamyl, the other oxime carbamate, was not toxic to any of them. Carbaryl and carbofuran at low concentrations were lethal to A. caliginosa, A. chlorotica and L. rubellus, but E. foetida could tolerate high concentrations without dying, although low concentrations severely affected its ability to work the soil or to disappear from the soil surface. Paraoxon, parathion, trichloronate and gamma-HCH were moderately toxic with low lethal effect to all species. The ability to work the soil was moderately affected by parathion, trichloronate and gamma-HCH. PHMD was toxic to all the species. The lethal and non-lethal effects of the pesticides are discussed in relation to their possible biochemical mode of action in earthworms, and the data are compared with published information from field trials.     

Rapid in vitro screening assay for immunotoxic effects of organophosphorus and carbamate insecticides on the generation of cytotoxic T-lymphocyte responses

There has been an increasing need for rapid and easily interpreted techniques for the screening of possible immunotoxicants. Besides the obvious detrimental effects of exposure to immunosuppressive agents, the modulation of the immune system which results from exposure to these toxicants may be a sensitive index to the toxicologic effects of such agents. Other researchers have proposed assays to screen the effect of in vitro treatment with immunotoxicants on mitogenic and humoral immune responses. In this report, we have described an in vitro technique for screening the effect of immunotoxicants, in the presence and absence of a NADPH fortified liver postmitochondrial supernatant (S-9) from Arochlor 1254-treated rat, on another aspect of the mammalian immune system, the generation of a T-cell-mediated cytolytic (CTL) response. This enzyme system altered the effect of organophosphorus compounds on the generation of a CTL response. Malathion and fenitrothion were no longer suppressive following this pretreatment; however, ethyl and methyl parathion and fenthion were only partially detoxified. In contrast, the S-9 enzyme system did not alter the effect of carbamate pesticides, carbaryl and carbofuran, on the generation of CTL responses. This report describes the effects of these seven organophosphorus and carbamate pesticides on the generation of the CTL response. In addition, some of the in vivo data published on the immunomodulatory effects of these compounds were collated from the literature and a correlation between in vitro and in vivo studies was discussed.     

The effects of DDT and dieldrin on rat peritoneal macrophages

The effects of DDT and dieldrin on cell population, viability, and phagocytic activity on the rat peritoneal macrophages were studied. It was observed that both pesticides, at low levels of concentration, exhibited a marked effect on this cell type. At the lowest concentrations tested both pesticides produced an increase in the macrophage population which appeared to be the result of a foreign-body response. At higher concentrations of pesticide this foreign-body response appears to be inhibited. The phagocytic activity of the cells steadily decreased as the concentration of the pesticide administered increased, and a decrease in cell viability with increased pesticide exposure was also noted.     

Lack of immunosuppressive effects of acute and subacute administration of malathion on murine cellular and humoral immune responses

Malathion has been previously shown to cause allergic responses and suppress the generation of a humoral immune response in vivo. In this study, the effect of in vivo administration of malathion on cellular, humoral and mitogenic responses was examined. Acute (50% LD₅₀) or subacute (10% LD₅₀ per day for 14 days) treatment with malathion in vivo did not affect the in vivo generation of specific antibody secreting cells to sheep red blood cells (SRBC) or cytotoxic T lymphocytes (CTL) to allogeneic tumor. However, 5 days following acute administration of malathion, there was a slight increase in humoral immune responsiveness. Acute treatment with 50% LD₅₀ purified malathion did not affect body weight, splenic cell number, or thymus size. However, mitogenic responses to Concanavalin A (Con A) and lipopolysaccharide (LPS) was significantly enhanced on all days tested following acute administration of malathion. In contrast, subacute treatment with malathion did not affect mitogenic response to Con A or LPS, but led to a significant decrease in thymic cell number.     

Stressor-specific induction of heat shock protein 70 in the freshwater prawn Macrobrachium malcolmsonii (H. Milne Edwards) exposed to the pesticides endosulfan and carbaryl

Agricultural run off that is contaminated with pesticides enters water bodies, thereby polluting the aquatic environment. The sensitivity of the freshwater prawn, Macrobrachium malcolmsonii, to such pesticides is well-documented. However, the stress response to sublethal concentrations of pesticides has scarcely been investigated. In the present study, the effect of two different sublethal concentrations (1/5th and 1/10th of LC₅₀ value) of endosulfan and carbaryl on the synthesis of hsp70 in various tissues of the prawn M. malcolmsonii was evaluated by Western blotting analysis. Among the tissues analyzed (gill, skeletal muscle, and hepatopancreas), induction of hsp70 synthesis was recorded only in the gill tissue of the prawns that had been exposed to either the high or low sublethal concentration of endosulfan. Induction of synthesis of hsp70 was not observed in any of the tissues sampled from the prawns that had been exposed to either the low or the high sublethal concentration of carbaryl. Pesticides interfere with the hydrophobic core of protein, thus leading to denaturation of the protein by exposing the lipophilic moieties to the aqueous environment. Specific induction of hsp70 in the gill possibly occurred since the gill is the route of exposure for pesticides in the prawns. The absence of induction of hsp70 synthesis in prawns that had been exposed to carbaryl suggests that induction of hsp70 synthesis is stressor-specific.     

Modeling environmental effects on enhanced carbofuran degradation

Prediction of the fate of pesticides in soil is of interest from an environmental (pollution) as well as an agricultural (efficacy, carryover) viewpoint. Two environmental parameters that control microbial degradation of pesticides in soil are moisture and temperature. This study was designed to quantify the impact of soil water content and temperature on microbial degradation rates of the insecticide carbofuran (2, 3-dihydro-2, 2-dimethylbenzofuran-7-yl methyl-carbamate). Carbofuran degradation was determined by monitoring the [ 14 C] carbondioxide production from soils amended with [carbonyl- 14 C]carbofuran. Soils were incubated at seven soil-water tensions over the range of 0–03 to 1–5 MPa, and at five temperatures (10°C to 30°C). The sigmoidal degradation kinetics observed from these incubations were modeled using a general saturation model. For the moisture experiments, maximum rate of hydrolysis and half-life (DT₅₀) were accurately modeled by an exponential relationship. The response of carbofuran degradation to temperature was also well described by an exponential relationship, from which it was estimated that the Q₁₀ associated with the maximum rate was 1.68, and the Q₁₀ for DT₅₀ was 1–89.     

Bioconversion of dieldrin by wood‐rotting fungi and metabolite detection

BACKGROUND: Dieldrin is one of the most persistent organochlorine pesticides, listed as one of the 12 persistent organic pollutants in the Stockholm Convention. Although microbial degradation is an effective way to remediate environmental pollutants, reports on aerobic microbial degradation of dieldrin are limited. Wood‐rotting fungi can degrade a wide spectrum of recalcitrant organopollutants, and an attempt has been made to select wood‐rotting fungi that can degrade dieldrin, and to identify the metabolite. RESULTS: Thirty‐four isolates of wood‐rotting fungi were investigated for their ability to degrade dieldrin. Strain YK543 degraded 39.1 ± 8.8% of dieldrin during 30 days of incubation. Phylogenetic analysis demonstrated that strain YK543 was closely related to the fungus Phlebia brevispora Nakasone TMIC33929, which has been reported as a fungus that can degrade chlorinated dioxins and polychlorinated biphenyls. 9‐Hydroxydieldrin was detected as a metabolite in the cultures of strain YK543. CONCLUSION: It is important to select the microorganisms that degrade organic pollutants, and to identify the metabolic pathway for the development of bioremediation methods. Strain YK543 was selected as a fungus capable of degrading dieldrin. The metabolic pathway includes 9‐hydroxylation reported in rat's metabolism catalysed by liver microsomal monooxygenase. This is the first report of transformation of dieldrin to 9‐hydroxydieldrin by a microorganism. Copyright © 2010 Society of Chemical Industry     

桑脉带相关病毒N蛋白多克隆抗体的制备

 桑脉带相关病毒(Mulberry vein banding associated virus,MVBaV)属于番茄斑萎病毒科(Tospoviridae)正番茄斑萎病毒属(Orthotospovirus)的新成员,是广西桑树病毒病的主要病原病毒。本研究将MVBaV核外壳蛋白(nucleocapsid protein, N protein)基因连接到pET-30a原核表达载体上,获得重组表达载体pET-30a-MVBaV-N并转化大肠杆菌菌株BL21(DE3),经IPTG诱导可表达产生一个含His标签、分子量约36.0 kDa的融合蛋白。用 Ni^{2 +} -NTA树脂纯化融合蛋白,将其免疫日本大耳兔制备多克隆抗体。间接ELISA测定抗体的效价为1∶256 000。Western blot 检测结果显示,该多克隆抗体在稀释倍数1∶1 000时与细菌表达的融合N蛋白及感病桑叶中的N蛋白产生特异性识别,但不与寄主蛋白产生交叉反应,表明具有良好的特异性和较高的灵敏度。将抗体按1∶2 500稀释后进行间接ELISA,可有效检出桑叶中的MVBaV。MVBaV N蛋白抗体的成功研制,为桑脉带病毒病的诊断及MVBaV与寄主相互作用机制的研究提供了重要的试剂。     

昆虫病原真菌在害虫防治中对天敌生物的影响研究进展

昆虫病原真菌是一类重要的微生物杀虫剂,广泛应用于农林害虫的生物防治。由于寄主范围广和主动侵染的特点,昆虫病原真菌在侵染、致死靶标害虫的同时,对包括天敌昆虫在内的非靶标节肢动物等会产生潜在的致病或亚致死风险。本文总结了昆虫病原真菌在害虫防治中的研究进展及对天敌生物的影响,并展望了昆虫病原真菌作为极具潜力的生物农药与天敌生物联合防治害虫的未来发展方向。     

Blood organochlorine pesticide levels in Virginia residents.

This study attempts to establish 1972 baseline levels for 31 organochlorine pesticides and industrial chemicals in postmortem human whole blood in Virginia. These pesticides and industrial chemicals have been detected previously in other parts of the food chain and environment. In the present study DDT and its metabolites, DDE and TDE, were detected most frequently and at highest levels. DDT and DDE tended to appear more frequently as people grew older although TDE levels remained constant. Dieldrin and lindane showed peak levels in the middle age group. Analyzing distribution of pesticides in blood by sex showed that females had higher levels of lindane and dieldrin and males had higher levels of DDT, DDE, and TDE. Analyzing racial distribution showed blacks with higher levels of DDT, TDE, and DDE and indicated little difference from whites for lindane and dieldrin. Higher levels were found in Richmond and Norfolk than in the Fairfax and Roanoke regions.     

Development of a monoclonal antibody immunoassay for the eyespot pathogen Pseudocercosporella herpotrichoides

A double-antibody-sandwich ELISA test has been developed for the detection of Pseudocercosporella herpotrichoides using a highly specific monoclonal antibody PH-10 as the capture antibody and genus-specific rabbit polyclonal antiserum as the detector antibody. The assay recognizes extracts from plants both artificially and naturally infected with P. herpotrichoides giving at least three-fold higher absorbance values with extracts from Pseudocercosporella-infected tissue than with extracts from healthy tissues or from tissues naturally infected with Microdochium nivale, Rhizoctonia cerealis or material artificially inoculated with P. anguioides. The assay tested positively against all isolates of P. herpotrichoides , including both W-type and R-type isolates. In this assay system, extraction of the antigen from the stem bases of infected plants is a one-step process not requiring any dilution procedures. The assay can be used to detect the pathogen in presymptomatic infected seedlings. The immunogen used to generate the specific monoclonal antibody and the rabbit antiserum was a mycelial extract from which the high-molecular-weight proteins and glycoproteins had been removed by ammonium sulphate precipitation. The high-molecular-weight fraction was shown to contain cross-reactive antigens; it induced antiserum in mice that cross-reacted with the other stem-base fungi even at high dilutions. The monoclonal antibody PH-10 is an IgM antibody. Heat and periodate treatment of the antigen indicate that it is a glycoprotein and that the epitope recognized by the antibody is a protein.     

CTMAB-膨润土对水溶液中4种农药的吸附特性

用溴化十六烷基三甲铵(CTMAB) 制得改性膨润土, 研究了CTMAB-膨润土吸附水中甲萘威、甲基对硫磷、克百威、多菌灵的性能和适宜条件。结果表明: CTMAB-膨润土对水溶液中4 种农药有较强的吸附能力, 且与CTMAB 在膨润土上的实际交换量有关, 随着表面活性剂浓度的增大而增大; 但CTMAB 浓度≥4% 时, 实际发生吸附的农药就不再随着加入量的增加而增大。4 种农药的吸附等温线呈线性, 表明分配模式是主要的吸附形式。有机膨润土对4 种农药的吸附很快, 大部分农药在10 m in 内被吸附。pH 值变化对吸附有不同的影响, 并与农药性质有关: 低pH 值会降低有机农药的吸附量, 4 种农药在pH4～ 10 时吸附量较稳定,高pH 值导致多菌灵的吸附量增加, 而甲萘威、甲基对硫磷和克百威有分解现象。     

斑痣悬茧蜂对受药寄主幼虫的选择性及其后代表现

为探究受到杀虫剂亚致死影响的寄主幼虫对寄生蜂的寄主选择及其子代蜂的影响,以容性寄生蜂斑痣悬茧蜂Meteorus pulchricornis为研究对象,以氯氰菊酯亚致死浓度处理的甜菜夜蛾Spodoptera exigua4龄幼虫为寄主幼虫,进行非选择性和选择性试验。非选择性试验表明,斑痣悬茧蜂成功寄生（完成化蛹）的概率随受药寄主的体重增大而提高,而且受药寄主有效存活的概率亦随其体重增大而提高;与对照寄主相比,寄生蜂对受药寄主的寄生率降低60.2%、子代蜂发育历期显著延长、子代蜂体型（用后足胫节长度表示）显著增大。与来自对照寄主的子代蜂相比,来自受药寄主的子代蜂的寄生能力（用寄生率表示）未受影响,但其后代的结茧率降低10%、发育历期显著缩短、体型显著增大,说明羽化蜂的发育适合度得到了提高。选择性试验结果得出不一致的结论,根据对寄生蜂攻击次数的分析,未发现其在对照与受药寄主之间存在显著偏好;但根据第2次攻击的寄主识别期变量进行的风险分析,受药寄主被寄生风险显著低于对照寄主（低59.7%）,说明寄生蜂偏好攻击对照寄主幼虫。研究结果说明,斑痣悬茧蜂通过偏好体型较大的寄主幼虫,而减轻了受到杀虫剂亚致死效应的间接不良影响。结果表明该寄生蜂具有鉴别出接受亚致死杀虫剂不久的寄主幼虫的能力。