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PloS One 2012Among herbivorous insects that have exploited agro-ecosystems, the peach-potato aphid, Myzus persicae, is recognized as one of the most important agricultural pests...
BACKGROUND
Among herbivorous insects that have exploited agro-ecosystems, the peach-potato aphid, Myzus persicae, is recognized as one of the most important agricultural pests worldwide. Uses over 400 plant species and has evolved different insecticides resistance mechanisms. As M. persicae feeds upon a huge diversity of hosts, it has been exposed to a wide variety of plant allelochemicals, which probably have promoted a wide range of detoxification systems.
METHODOLOGY/PRINCIPAL FINDINGS
In this work we (i) evaluated whether insecticide resistance mutations (IRM) in M. persicae can give an advantage in terms of reproductive fitness when aphids face two hosts, pepper (Capsicum annuum) a suitable host and radish (Raphanus sativus) the unfavorable host and (ii) examined the transcriptional expression of six genes that are known to be up-regulated in response to insecticides. Our results show a significant interaction between host and IRM on the intrinsic rate of increase (r(m)). Susceptible genotypes (not carrying insensitivity mutations) had a higher r(m) on pepper, and the transcriptional levels of five genes increased on radish. The r(m) relationship was reversed on the unfavorable host; genotypes with multiple IRM exhibited higher r(m), without altering the transcriptional levels of the studied genes. Genotypes with one IRM kept a similar r(m) on both hosts, but they increased the transcriptional levels of two genes.
CONCLUSIONS/SIGNIFICANCE
Although we have studied only nine genotypes, overall our results are in agreement with the general idea that allelochemical detoxification systems could constitute a pre-adaptation for the development of insecticide resistance. Genotypes carrying IRM exhibited a higher r(m) than susceptible genotypes on radish, the more unfavorable host. Susceptible genotypes should be able to tolerate the defended host by up-regulating some metabolic genes that are also responding to insecticides. Hence, our results suggest that the trade-off among resistance mechanisms might be quite complex, with a multiplicity of costs and benefits depending on the environment.
Topics: Adaptation, Physiological; Animals; Aphids; Capsicum; Carbamates; Carboxylesterase; Cathepsin B; Cytochrome P-450 Enzyme System; Evolution, Molecular; Gene Expression Regulation; Genotype; Glutathione Transferase; HSP70 Heat-Shock Proteins; Host Specificity; Humans; Insect Proteins; Insecticide Resistance; Insecticides; Isoenzymes; Mutation; Prunus; Pyrimidines; Raphanus; Reverse Transcriptase Polymerase Chain Reaction; Up-Regulation
PubMed: 22685539
DOI: 10.1371/journal.pone.0036810 -
PloS One 2012Insecticide resistance is one of the best examples of rapid micro-evolution found in nature. Since the development of the first synthetic insecticide in 1939, humans...
BACKGROUND
Insecticide resistance is one of the best examples of rapid micro-evolution found in nature. Since the development of the first synthetic insecticide in 1939, humans have invested considerable effort to stay ahead of resistance phenotypes that repeatedly develop in insects. Aphids are a group of insects that have become global pests in agriculture and frequently exhibit insecticide resistance. The green peach aphid, Myzus persicae, has developed resistance to at least seventy different synthetic compounds, and different insecticide resistance mechanisms have been reported worldwide.
METHODOLOGY/PRINCIPAL FINDINGS
To further characterize this resistance, we analyzed genome-wide transcriptional responses in three genotypes of M. persicae, each exhibiting different resistance mechanisms, in response to an anti-cholinesterase insecticide. The sensitive genotype (exhibiting no resistance mechanism) responded to the insecticide by up-regulating 183 genes primarily ones related to energy metabolism, detoxifying enzymes, proteins of extracellular transport, peptidases and cuticular proteins. The second genotype (resistant through a kdr sodium channel mutation), up-regulated 17 genes coding for detoxifying enzymes, peptidase and cuticular proteins. Finally, a multiply resistant genotype (carrying kdr and a modified acetylcholinesterase), up-regulated only 7 genes, appears not to require induced insecticide detoxification, and instead down-regulated many genes.
CONCLUSIONS/SIGNIFICANCE
This study suggests strongly that insecticide resistance in M. persicae is more complex that has been described, with the participation of a broad array of resistance mechanisms. The sensitive genotype exhibited the highest transcriptional plasticity, accounting for the wide range of potential adaptations to insecticides that this species can evolve. In contrast, the multiply resistant genotype exhibited a low transcriptional plasticity, even for the expression of genes encoding enzymes involved in insecticide detoxification. Our results emphasize the value of microarray studies to search for regulated genes in insects, but also highlights the many ways those different genotypes can assemble resistant phenotypes depending on the environmental pressure.
Topics: Animals; Aphids; Carbamates; Gene Expression Regulation; Genome, Insect; Genotype; Humans; Insect Proteins; Insecticide Resistance; Insecticides; Oligonucleotide Array Sequence Analysis; Prunus; Pyrimidines; Reverse Transcriptase Polymerase Chain Reaction; Transcriptome
PubMed: 22685538
DOI: 10.1371/journal.pone.0036366 -
Iranian Journal of Pharmaceutical... 2011A gas chromatography mass spectrometry with spike calibration curve method was used to quantify three carbamate pesticides residue in cooked white rice and to estimate...
UNLABELLED
A gas chromatography mass spectrometry with spike calibration curve method was used to quantify three carbamate pesticides residue in cooked white rice and to estimate the reduction percentage of the cooking process duration. The selected pesticides are three carbamate pesticides including carbaryl and pirimicarb that their MRL is issued by "The Institute of Standards of Iran" and propoxur which is used as a widely consumed pesticide in rice.
THE ANALYTICAL METHOD ENTAILED THE FOLLOWING STEPS
1- Blending 15 g cooked sample with 120 mL acetonitrile for 1 min in solvent proof blender, 2- Adding 6 g NaCl and blending for 1 min, 3- Filtering upper layer through 25 g anhydrous Na2SO4, 4- Cleaning up with PSA and MgSO4, 5- Centrifuging for 7 min, 6- Evaporating about 0.3 mL and reconstituting in toluene till 1 mL, 7- Injecting 2 μL extract into GC/MS and analyzing by single quadruple selected ion monitoring GC/MS-SQ-SIM. The concentration of pesticides and the percentage of pesticides amounts after the cooking were determined by gas chromatography mass-spectrometry (GC/MS) using with interpolation of the relative peak areas for each pesticide to internal standard peak area in the sample on the spiked calibration curve. Calibration curve was linear over the range of 25 to 1000 ng/g, and LOQ was 25 ng/g for all three pesticides. The percent of loss for the three pesticides were 78%, 55% and 35% for carbaryl, propoxur and pirimicarb respectively. Different parameters such as vapor pressure, boiling point, and suspect ability of the compound to hydrolysis, could be responsible for the losing of pesticides during the cooking process.
PubMed: 24363690
DOI: No ID Found -
Acta Crystallographica. Section E,... Jul 2010In the title compound, C(11)H(18)N(4)O(2) (systematic name: 2-dimethyl-amino-5,6-dimethyl-pyrimidin-4-yl N,N-dimethyl-carb-amate), the pyrimidine ring and dimethyl-amino...
In the title compound, C(11)H(18)N(4)O(2) (systematic name: 2-dimethyl-amino-5,6-dimethyl-pyrimidin-4-yl N,N-dimethyl-carb-amate), the pyrimidine ring and dimethyl-amino group are almost in the same plane, making a dihedral angle of 1.6 (1)°. The dihedral angle between the mean plane of the pyrimidine ring and that of the dimethyl-carbamate group is 83.42 (5)°. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds contribute to the stabilization of the packing.
PubMed: 21588312
DOI: 10.1107/S160053681002684X -
Roczniki Panstwowego Zakladu Higieny 2008The aim of this paper was to present occurrence of plant protection product residues in apples in 2007. Gas chromatographic and spectroscopy methods were used. The most...
The aim of this paper was to present occurrence of plant protection product residues in apples in 2007. Gas chromatographic and spectroscopy methods were used. The most frequently found were fungicides: dithiocarbamate residues (18% of the analysed samples), captan residues (13%), pyrimethanil residues (6%) and insecticides: chlorpiryfos residues (6%), diazinon residues (6%) and pirimicarb residues (5%). 5.6% of analysed samples exceeded the national Maximum Residue Level established for apples. Violations were found for: flusilazole (n = 2), propiconazole (n = 2), cyprodinil (n = 1), dimethoate (n = 1), fenitrothion (n = 1).
Topics: Bridged Bicyclo Compounds; Chromatography, High Pressure Liquid; Environmental Exposure; Environmental Monitoring; Food Contamination; Fruit; Fungicides, Industrial; Humans; Insecticides; Pesticide Residues; Poland; Pyrimidines
PubMed: 19143426
DOI: No ID Found -
Journal of Chromatography. A Jun 2007We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different...
Development and validation of a multi-residue method for pesticide determination in honey using on-column liquid-liquid extraction and liquid chromatography-tandem mass spectrometry.
We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran, Methiocarb, Pirimicarb, Dimethoate, Fipronil, Imidacloprid; herbicides: Amidosulfuron, Rimsulfuron, Atrazine, Simazine, Chloroturon, Linuron, Isoxaflutole, Metosulam; fungicides: Diethofencarb) and 2 metabolites (Methiocarb sulfoxide and 2-Hydroxytertbutylazine) in honey. This method is based on an on-column liquid-liquid extraction (OCLLE) using diatomaceous earth as inert solid support and liquid chromatography (LC) coupled to mass spectrometry (MS) operating in tandem mode (MS/MS). Method specificity is ensured by checking retention time and theoretical ratio between two transitions from a single precursor ion. Linearity is demonstrated all along the range of concentration that was investigated, from 0.1 to 20 ng g(-1) raw honey, with correlation coefficients ranging from 0.921 to 0.999, depending on chemicals. Recovery rates obtained on home-made quality control samples are between 71 and 90%, well above the range defined by the EC/657/2002 document, but in the range we had fixed to ensure proper quantification, as levels found in real samples could not be corrected for recovery rates. Reproducibility is found to be between 8 and 27%. Calculated CCalpha and CCbeta (0.0002-0.943 ng g(-1) for CCalpha, and 0.0002-1.232 ng g(-1) for CCbeta) show the good sensitivity attained by this multi-residue analytical method. The robustness of the method has been tested in analyzing more than 100 raw honey samples collected from different areas in Belgium, as well as some wax and bee samples, with a slightly adapted procedure.
Topics: Chromatography, Liquid; Honey; Pesticide Residues; Reproducibility of Results; Sensitivity and Specificity; Tandem Mass Spectrometry
PubMed: 17416380
DOI: 10.1016/j.chroma.2007.03.035 -
Mededelingen (Rijksuniversiteit Te... 2001Vegetable open field areas increased for 15 years in Wallonia, mainly in Hesbaye. To be in accordance with quality standards, especially in terms of agro-chimical...
Vegetable open field areas increased for 15 years in Wallonia, mainly in Hesbaye. To be in accordance with quality standards, especially in terms of agro-chimical residues (R.M.L.), biological pest control was developed and allowed to reduce the insecticide use, leading to have safer fresh products. Among cultivated species in Wallonia, leguminous crops represent more than 85% of the vegetable production. To assess the impact of insecticide treatment on both pests (mainly aphids) and beneficial insects (predators and parasitoïds), broad bean (Vicia faba L.) fields were investigated during all the production duration. Twelve fields between Waremme and Hannut were visited weakly from May to July. In each field, control untreated and treated plots were investigated. Insects were caught using yellow traps and determined until the family level. Approximately 90.000 insects belonging to 59 major families (99% of captures) and 64 minor families were identified. These results showed that biodiversity in terms of family numbers was significantly higher in unsprayed plots. In addition, biodiversity and biomass (insect density) increased gradually during the season. Evaluation of pest and beneficial diversity and density was discussed in relation to aphicid (lambda-cyhalothrin, pirimicarb) treatments and the development of I.P.M. program in vegetable crops.
Topics: Animals; Belgium; Biomass; Female; Insecta; Insecticides; Male; Pest Control, Biological; Population Density; Population Dynamics; Vegetables; Vicia faba
PubMed: 12425061
DOI: No ID Found -
Environmental Health Perspectives Feb 2001Dermal exposure has become the major route of human occupational exposure to pesticides. Detergents are used as part of formulated pesticide products and are known to...
Dermal exposure has become the major route of human occupational exposure to pesticides. Detergents are used as part of formulated pesticide products and are known to change the barrier properties of human skin in vitro. However, studies on the influence of detergents as well as protective glove materials on dermal penetration of pesticides are scarce. In an experiment using in vitro static diffusion cells mounted with human skin, we evaluated the effect of nonylphenol-ethoxylate on dermal penetration of three extensively used pesticides--methiocarb, paclobutrazol, and pirimicarb--and the protection against dermal penetration offered by protective gloves made of latex or nitrile. There was a general tendency, though not statistically significant for all pesticides, for nonylphenolethoxylate to decrease the percutaneous penetration of the three pesticides. The nitrile generally offered better protection against percutaneous penetration of pesticides than did latex, but the degree of protection decreased over time and depended on the pesticides used.
Topics: Aged; Aged, 80 and over; Cadaver; Carbamates; Denmark; Detergents; Ethylene Glycols; Female; Gloves, Protective; Humans; Methiocarb; Middle Aged; Occupational Exposure; Pesticides; Pyrimidines; Skin Absorption; Triazoles
PubMed: 11266321
DOI: 10.1289/ehp.01109129 -
Occupational and Environmental Medicine Nov 2000The dominant route of occupational exposure to pesticides in horticulture is dermal. However, preventive measures are seldom used when handling plant cultures recently...
OBJECTIVES
The dominant route of occupational exposure to pesticides in horticulture is dermal. However, preventive measures are seldom used when handling plant cultures recently treated with pesticides, thus causing significant dermal exposure and potential absorption. Assessment of exposure often depends on biological monitoring of blood or urine samples. The skin often acts as a temporary reservoir for chemicals before absorption. Failure to consider the lag time between dermal exposure and appearance of pesticide or metabolites in the general circulation may lead to false conclusions about assessment of exposure.
METHODS
In an experimental model in which in vitro static diffusion cells were mounted with human skin, dermal penetration of three extensively used pesticides (methiocarb, paclobutrazol, pirimicarb) was evaluated.
RESULTS
Pirimicarb and paclobutrazol had comparable rates of dermal penetration and lag times of around 18 hours. Methiocarb had a considerably shorter lag time. Dermal penetration continued for extended periods after exposure had ended.
CONCLUSIONS
With lag times sometimes considerably longer than a normal working day, biological monitoring at the end of exposure may seriously underestimate the actual exposure. There may be implications for regulatory guidelines, which often require only 24 hour observation periods.
Topics: Adult; Aged; Aged, 80 and over; Female; Humans; In Vitro Techniques; Insecticides; Methiocarb; Middle Aged; Occupational Exposure; Permeability; Plant Growth Regulators; Skin; Skin Absorption; Time Factors; Triazoles
PubMed: 11024196
DOI: 10.1136/oem.57.11.734