Herbicides: Pesticides used to destroy unwanted vegetation, especially various types of weeds, grasses (POACEAE), and woody plants. Some plants develop HERBICIDE RESISTANCE.Herbicide Resistance: Diminished or failed response of PLANTS to HERBICIDES.Atrazine: A selective triazine herbicide. Inhalation hazard is low and there are no apparent skin manifestations or other toxicity in humans. Acutely poisoned sheep and cattle may show muscular spasms, fasciculations, stiff gait, increased respiratory rates, adrenal degeneration, and congestion of the lungs, liver, and kidneys. (From The Merck Index, 11th ed)2,4-Dichlorophenoxyacetic Acid: An herbicide with irritant effects on the eye and the gastrointestinal system.2-Methyl-4-chlorophenoxyacetic Acid: A powerful herbicide used as a selective weed killer.Linuron: A selective pre- and post-emergence herbicide. (From Merck Index, 11th ed)Plant Weeds: A plant growing in a location where it is not wanted, often competing with cultivated plants.2,4,5-Trichlorophenoxyacetic Acid: An herbicide with strong irritant properties. Use of this compound on rice fields, orchards, sugarcane, rangeland, and other noncrop sites was terminated by the EPA in 1985. (From Merck Index, 11th ed)Acetolactate Synthase: A flavoprotein enzyme that catalyzes the formation of acetolactate from 2 moles of PYRUVATE in the biosynthesis of VALINE and the formation of acetohydroxybutyrate from pyruvate and alpha-ketobutyrate in the biosynthesis of ISOLEUCINE. This enzyme was formerly listed as EC 126.96.36.199.Trifluralin: A microtubule-disrupting pre-emergence herbicide.Simazine: A triazine herbicide.3-Phosphoshikimate 1-Carboxyvinyltransferase: An enzyme of the shikimate pathway of AROMATIC AMINO ACID biosynthesis, it generates 5-enolpyruvylshikimate 3-phosphate and ORTHOPHOSPHATE from PHOSPHOENOLPYRUVATE and shikimate-3-phosphate. The shikimate pathway is present in BACTERIA and PLANTS but not in MAMMALS.Weed Control: The prevention of growth and or spread of unwanted plants.Paraquat: A poisonous dipyridilium compound used as contact herbicide. Contact with concentrated solutions causes irritation of the skin, cracking and shedding of the nails, and delayed healing of cuts and wounds.Picloram: A picolinic acid derivative that is used as a herbicide.Dicamba: A chlorinated organic herbicide.Protoporphyrinogen Oxidase: A membrane-bound flavoenzyme that catalyzes the oxygen-dependent aromatization of protoporphyrinogen IX (Protogen) to protoporphyrin IX (Proto IX). It is the last enzyme of the common branch of the HEME and CHLOROPHYLL pathways in plants, and is the molecular target of diphenyl ether-type herbicides. VARIEGATE PORPHYRIA is an autosomal dominant disorder associated with deficiency of protoporphyrinogen oxidase.Diuron: A pre-emergent herbicide.Triazines: Heterocyclic rings containing three nitrogen atoms, commonly in 1,2,4 or 1,3,5 or 2,4,6 formats. Some are used as HERBICIDES.Lolium: Common member of the Gramineae family used as cattle FODDER. It harbors several fungi and other parasites toxic to livestock and people and produces allergenic compounds, especially in its pollen. The most commonly seen varieties are L. perenne, L. multiflorum, and L. rigidum.Delftia acidovorans: A species of gram-negative rod-shaped bacteria found ubiquitously and formerly called Comamonas acidovorans and Pseudomonas acidovorans. It is the type species of the genus DELFTIA.ToluidinesDefoliants, Chemical: Herbicides that remove leaves from trees and growing plants. They may be either organic or inorganic. Several of the more persistent types have been used in military operations and many are toxic. (From Hawley's Condensed Chemical Dictionary, 11th ed)Chlorophenols: Phenols substituted with one or more chlorine atoms in any position.Pesticides: Chemicals used to destroy pests of any sort. The concept includes fungicides (FUNGICIDES, INDUSTRIAL); INSECTICIDES; RODENTICIDES; etc.Sulfonylurea CompoundsAminobutyrates: Derivatives of BUTYRIC ACID that contain one or more amino groups attached to the aliphatic structure. Included under this heading are a broad variety of acid forms, salts, esters, and amides that include the aminobutryrate structure.Agriculture: The science, art or practice of cultivating soil, producing crops, and raising livestock.4-Hydroxyphenylpyruvate Dioxygenase: An enzyme that catalyzes the conversion of 4-hydroxyphenylpyruvate plus oxygen to homogentisic acid and carbon dioxide. EC 188.8.131.52.Methylurea Compounds: Urea compounds which are substituted with one or more methyl groups.Propanil: A chlorinated anilide that is used as an herbicide.Phenyl Ethers: Ethers that are linked to a benzene ring structure.Agrochemicals: Chemicals used in agriculture. These include pesticides, fumigants, fertilizers, plant hormones, steroids, antibiotics, mycotoxins, etc.Diquat: A contact herbicide used also to produce desiccation and defoliation. (From Merck Index, 11th ed)Plants, Genetically Modified: PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.Pesticide Residues: Pesticides or their breakdown products remaining in the environment following their normal use or accidental contamination.Glycine: A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.Agricultural Workers' Diseases: Diseases in persons engaged in cultivating and tilling soil, growing plants, harvesting crops, raising livestock, or otherwise engaged in husbandry and farming. The diseases are not restricted to farmers in the sense of those who perform conventional farm chores: the heading applies also to those engaged in the individual activities named above, as in those only gathering harvest or in those only dusting crops.Heterocyclic Compounds, 2-Ring: A class of organic compounds containing two ring structures, one of which is made up of more than one kind of atom, usually carbon plus another atom. The heterocycle may be either aromatic or nonaromatic.Crops, Agricultural: Cultivated plants or agricultural produce such as grain, vegetables, or fruit. (From American Heritage Dictionary, 1982)Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Fungicides, Industrial: Chemicals that kill or inhibit the growth of fungi in agricultural applications, on wood, plastics, or other materials, in swimming pools, etc.Biodegradation, Environmental: Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.Glycolates: Derivatives of ACETIC ACID which contain an hydroxy group attached to the methyl carbon.Cyclohexanones: Cyclohexane ring substituted by one or more ketones in any position.Amaranthus: A plant genus, in the family AMARANTHACEAE, best known as a source of high-protein grain crops and of Red Dye No. 2 (AMARANTH DYE). Tumbleweed sometimes refers to Amaranthus but more often refers to SALSOLA.Soil Pollutants: Substances which pollute the soil. Use for soil pollutants in general or for which there is no specific heading.Acetamides: Derivatives of acetamide that are used as solvents, as mild irritants, and in organic synthesis.Drug Resistance: Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.Acetyl-CoA Carboxylase: A carboxylating enzyme that catalyzes the conversion of ATP, acetyl-CoA, and HCO3- to ADP, orthophosphate, and malonyl-CoA. It is a biotinyl-protein that also catalyzes transcarboxylation. The plant enzyme also carboxylates propanoyl-CoA and butanoyl-CoA (From Enzyme Nomenclature, 1992) EC 184.108.40.206.Alismatidae: A plant subclass of the class Liliopsida (monocotyledons) in the Chronquist classification system. This is equivalent to the Alismatales order in the APG classification system. It is a primitive group of more or less aquatic plants.Oxidoreductases Acting on CH-CH Group Donors: A subclass of enzymes which includes all dehydrogenases acting on carbon-carbon bonds. This enzyme group includes all the enzymes that introduce double bonds into substrates by direct dehydrogenation of carbon-carbon single bonds.
Herbicide: Herbicide(s), also commonly known as weedkillers, are pesticides used to control unwanted plants. Selective herbicides control specific weed species, while leaving the desired crop relatively unharmed.List of varieties of genetically modified maize: This is a partial list of varieties of maize that have been modified.Atrazine chlorohydrolase: Atrazine Chlorohydrolase (AtzA) is an enzyme (E.C.Chromotropic acidMCPAAuxin: Auxins (plural of auxin ) are a class of plant hormones (or plant growth substances) with some morphogen-like characteristics. Auxins have a cardinal role in coordination of many growth and behavioral processes in the plant's life cycle and are essential for plant body development.Phenylacetylcarbinol: -PAC(R)-PACTrifluralinSimazineEPSP synthaseWeed control: Weed control is the botanical component of pest control, which attempts to stop weeds, especially noxious or injurious weeds, from competing with domesticated plants and livestock. Many strategies have been developed in order to contain these plants.Paraquat murders: The paraquat murders were a series of indiscriminate poisonings carried out in Japan in 1985. Police were unable to gather any evidence about the murders other than they were caused by a poisoned beverage that was left inside or around vending machines.PicloramDicambaAcifluorfenDimethylureaTriazine: A triazine is class of nitrogen-containing heterocycles. The parent molecules' molecular formula is 333.DimethylanilineU.S.-Vietnam Dialogue Group on Agent Orange/Dioxin: The U.S.DichlorophenolPesticides in the United States: Pesticides in the United States are used predominantly by the agricultural sector,Kellogg RL, Nehring R, Grube A, Goss DW, and Plotkin S (February 2000), Environmental indicators of pesticide leaching and runoff from farm fields. United States Department of Agriculture Natural Resources Conservation Service.GliquidoneChilalo Agricultural Development Union: Chilalo Agricultural Development Union (CADU) is the first comprehensive package project established in Arsi Zone, Oromia Region, Ethiopia to modernize traditional subsistence agriculture. The major components of the package programmes include fertilizers, ameliorated seeds, farm credits, marketing facilities, better tools and implements, and improved storage facilities.Tyrosinemia type IIIMonolinuronPropanilAllyl phenyl etherAgrochemical F.C.: James Omondi|DiquatPlant perception (physiology): Plant perception is the ability of plants to sense and respond to the environment to adjust their morphology, physiology and phenotype accordingly. Other disciplines such as plant physiology, ecology and molecular biology are used to assess this ability.Pesticide residues in New Zealand: Pesticide residues are of concern in New Zealand and foods are regularly checked to see if they are within set limits.Glycine (plant): Glycine is a genus in the bean family Fabaceae. The best known species is the soybean (Glycine max).Basic aromatic ring: Basic aromatic rings are aromatic rings in which the lone pair of electrons of a ring-nitrogen atom is not part of the aromatic system and extends in the plane of the ring. This lone pair is responsible for the basicity of these nitrogenous bases, similar to the nitrogen atom in amines.Plant breeders' rights: Plant breeders' rights (PBR), also known as plant variety rights (PVR), are rights granted to the breeder of a new variety of plant that give the breeder exclusive control over the propagating material (including seed, cuttings, divisions, tissue culture) and harvested material (cut flowers, fruit, foliage) of a new variety for a number of years.Fungicide: Fungicides are biocidal chemical compounds or biological organisms used to kill or inhibit fungi or fungal spores.Interaction of 2,4,5-trich|orophenylsulphonylmethyl thiocyanate with fungal spores Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, and profit.BiodegradationCyclohexanone monooxygenase: Cyclohexanone monooxygenase (, cyclohexanone 1,2-monooxygenase, cyclohexanone oxygenase, cyclohexanone:NADPH:oxygen oxidoreductase (6-hydroxylating, 1,2-lactonizing)) is an enzyme with system name cyclohexanone,NADPH:oxygen oxidoreductase (lactone-forming). This enzyme catalyses the following chemical reactionAgnes Benidickson Tricolour Award: The Tricolour Award and induction into the Tricolour Society is the highest tribute that can be paid to a student of Queen's University in Kingston, Ontario for valuable and distinguished service to the University in non-academic and non-athletic activities. Such service may have been confined to a single field, or it may have taken the form of a significant contribution over a wide range of activities.PyromorphiteDimethylacetamideACACB: Acetyl-CoA carboxylase 2 also known as ACC-beta or ACC2 is an enzyme that in humans is encoded by the ACACB gene.Posidonia Shale
(1/1376) Semiautomated preparation of 3,5,6-trichloro-2-pyridinol in human urine using a Zymate XP laboratory robot with quantitative determination by gas chromatography-negative-ion chemical ionization mass spectrometry.
A rapid and sensitive semiautomated method was developed for quantitation of the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCP) in human urine. A Zymark Zymate XP laboratory robotics system was used to mix urine samples, transfer aliquots, add the stable-isotope-labeled TCP internal standard (13C2- or 13C2,15N-), and liberate conjugates of TCP from urine via acid hydrolysis. Samples were manually extracted into toluene, derivatized, and analyzed by gas chromatography-negative-ion chemical ionization mass spectrometry. Determination of the metabolic TCP was performed by selected ion monitoring of the dichloropyridinol fragment ions: m/z 161 for TCP and m/z 165 for 13C2-TCP or m/z 168 for 13C2,15N-TCP. Interday precision and accuracy were demonstrated over 3 years of analyses using the 13C2-TCP internal standard, with an average recovery from fortified urine samples of 93+/-12% (N = 54, concentration range 1-140 ng/mL). The method was found to be linear over the range of 0.5 to 200 ng/mL, and the limit of detection for TCP in urine was estimated to be 0.2 ng/mL with a limit of quantitation of 1 ng/mL. The effect of solids distribution on the concentration of TCP in the thawed urine samples was examined, and the results indicated that homogeneous distribution is critical for quantitation. The precision and accuracy of the automated method with respect to the transfer of homgeneous urine aliquots and delivery of internal standard yielded equivalent or improved results over the manual techniques. Overall, this method is more simple than existing methodologies, and it yields results with improved precision, accuracy, and sensitivity over previously developed methods. (+info)
(2/1376) Effect of phenylurea herbicides on soil microbial communities estimated by analysis of 16S rRNA gene fingerprints and community-level physiological profiles.
The effect of three phenyl urea herbicides (diuron, linuron, and chlorotoluron) on soil microbial communities was studied by using soil samples with a 10-year history of treatment. Denaturing gradient gel electrophoresis (DGGE) was used for the analysis of 16S rRNA genes (16S rDNA). The degree of similarity between the 16S rDNA profiles of the communities was quantified by numerically analysing the DGGE band patterns. Similarity dendrograms showed that the microbial community structures of the herbicide-treated and nontreated soils were significantly different. Moreover, the bacterial diversity seemed to decrease in soils treated with urea herbicides, and sequence determination of several DGGE fragments showed that the most affected species in the soils treated with diuron and linuron belonged to an uncultivated bacterial group. As well as the 16S rDNA fingerprints, the substrate utilization patterns of the microbial communities were compared. Principal-component analysis performed on BIOLOG data showed that the functional abilities of the soil microbial communities were altered by the application of the herbicides. In addition, enrichment cultures of the different soils in medium with the urea herbicides as the sole carbon and nitrogen source showed that there was no difference between treated and nontreated soil in the rate of transformation of diuron and chlorotoluron but that there was a strong difference in the case of linuron. In the enrichment cultures with linuron-treated soil, linuron disappeared completely after 1 week whereas no significant transformation was observed in cultures inoculated with nontreated soil even after 4 weeks. In conclusion, this study showed that both the structure and metabolic potential of soil microbial communities were clearly affected by a long-term application of urea herbicides. (+info)
(3/1376) Cytotoxic effect of paraquat on rat C6 glioma cells: evidence for the possibility of non-oxidative damage to the cells.
Although paraquat has been shown to cause oxidative damage to neuronal cells, little is known about its effect on glial cells. Thus the effect of paraquat on glial cells was examined using rat C6 glioma cells as a model system. Paraquat reduced cell viability in a concentration- and time-dependent manner, and this toxic effect was not significantly attenuated by various kinds of antioxidants. Furthermore, paraquat failed to increase 8-hydroxy-deoxyguanosine formation in the cells. These results indicate that paraquat can be toxic to glial cells and suggest that this cytotoxic effect may not be associated with the oxidative damage to the cells. (+info)
(4/1376) High-performance liquid chromatography column switching applied to the trace determination of herbicides in environmental and drinking water samples.
A selective and sensitive coupled-column high-performance liquid chromatographic method is developed for the simultaneous determination of 5 phenylurea herbicides (monuron, linuron, isoproturon, monolinuron, and diuron) in environmental and drinking water samples. Sample clean-up is performed automatically by means of a column switching technique. Using 2 octadecyl silica columns connected via two programmable 6-port valves and ultraviolet detection at 244 nm, the aforementioned compounds can be determined at the low concentration levels required for pesticide residue analysis in water samples. A mobile phase consisting of a mixture of methanol-water (55:45, v/v) is pumped at 1 mL/min. For the 5 phenylureas, high recoveries ranging from 94.9 to 101.6%, good reproducibility with relative standard deviations lower than 5%, and wide linear ranges up to 20 micrograms/L are observed with determination limits of 0.05 microgram/L. The method is successfully applied to the screening of different environmental water samples such as surface, ground, rain, and drinking water. (+info)
(5/1376) Construction and characterization of a functional mutant of Synechocystis 6803 harbouring a eukaryotic PSII-H subunit.
A Synechocystis 6803 mutant carrying a chimaeric photosystem II (PSII), in which the Zea mays PsbH subunit (7.7 kDa calculated molecular mass) replaces the cyanobacterial copy (7.0 kDa), was constructed. With the exception of the N-terminal 12 amino acid extension, which has a phosphorylatable threonine, the eukaryotic polypeptide is 78% homologous to its bacterial counterpart. Biochemical characterization of this mutant shows that it expresses the engineered gene correctly and is competent for photoautotrophic growth. Fluorescence analysis and oxygen evolution measurements in the presence of exogenous acceptors indicate that the observed phenotype results from a chimaeric PSII rather than from the absence of function associated with PsbH, suggesting that the heterologous protein is assembled into a functional PSII. Inhibition of oxygen evolution by herbicides belonging to different classes shows that the sensitivity of the mutant PSII is changed only towards phenolic compounds. This result indicates slight conformational modification of the QB/herbicide binding pocket of the D1 polypeptide caused by the bulky PsbH protein in the mutant, and also suggests close structural interaction of the D1 and PsbH subunits in the topological arrangement of PSII. (+info)
(6/1376) A comparison of electron-capture GLC, electrolytic-conductivity GLC and UV-absorption HPLC for the analysis of some herbicides in foods.
A comparison of gas chromatography with electron-capture or electrolytic-conductivity (nitrogen mode) detection, and high-pressure liquid chromatography (HPLC) with UV-absorption detection (254 nm) was carried out for the analysis of several herbicides in foods. Linuron, propanil, terbacil, benzoylprop-ethyl, and the fungicide DCNA in samples of cabbage, corn, potato, and wheat spiked at 2 and 0.2 ppm were examined. The pesticides were extracted with acetone, partitioned into petroleum ether-methylene chloride, and cleaned up on a 2% deactivated Florisil column before direct chromatographic analysis. Electron-capture gas-liquid chromatography (GLC) was most suitable for DCNA and benzoylprop-ethyl while UV-absorption HPLC was best for terbacil analysis. Linuron and propanil gave similar results for both electron-capture GLC and HPLC. Electrolytic-conductivity GLC could detect all pesticides at the 0.2 ppm level and exhibited the least number of extraneous peaks in the chromatograms. (+info)
(7/1376) Selected phenolic compounds in cultivated plants: ecologic functions, health implications, and modulation by pesticides.
Phenolic compounds are widely distributed in the plant kingdom. Plant tissues may contain up to several grams per kilogram. External stimuli such as microbial infections, ultraviolet radiation, and chemical stressors induce their synthesis. The phenolic compounds resveratrol, flavonoids, and furanocoumarins have many ecologic functions and affect human health. Ecologic functions include defense against microbial pathogens and herbivorous animals. Phenolic compounds may have both beneficial and toxic effects on human health. Effects on low-density lipoproteins and aggregation of platelets are beneficial because they reduce the risk of coronary heart disease. Mutagenic, cancerogenic, and phototoxic effects are risk factors of human health. The synthesis of phenolic compounds in plants can be modulated by the application of herbicides and, to a lesser extent, insecticides and fungicides. The effects on ecosystem functioning and human health are complex and cannot be predicted with great certainty. The consequences of the combined natural and pesticide-induced modulating effects for ecologic functions and human health should be further evaluated. (+info)
(8/1376) Induction of the multispecific organic anion transporter (cMoat/mrp2) gene and biliary glutathione secretion by the herbicide 2,4,5-trichlorophenoxyacetic acid in the mouse liver.
The canalicular multispecific organic anion transporter, cMoat, is an ATP-binding-cassette protein expressed in the canalicular domain of hepatocytes. In addition to the transport of endo- and xenobiotics, cMoat has also been proposed to transport GSH into bile, the major driving force of bile-acid-independent bile flow. We have shown previously that the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a peroxisome-proliferator agent, significantly increases bile-acid-independent bile flow in mice. On this basis, the effect of the herbicide on cMoat gene expression was studied. A 3.6-fold increase in cMoat mRNA levels and a 2.5-fold increase in cMoat protein content were observed in the liver of mice fed on a diet supplemented with 0.125% 2,4,5-T. These effects were due to an increased rate of gene transcription (3.9-fold) and were not associated with peroxisome proliferation. Significant increases in bile flow (2.23+/-0.39 versus 1.13+/-0.15 microl/min per g of liver; P<0.05) and biliary GSH output (7.40+/-3.30 versus 2.65+/-0.34 nmol/min per g of liver; P<0.05) were observed in treated animals. The hepatocellular concentration of total glutathione also increased in hepatocytes of treated mice (10.95+/-0.84 versus 5.12+/-0.47 mM; P<0.05), because of the induction (2.4-fold) of the heavy subunit of the gamma-glutamylcysteine synthetase (GCS-HS) gene. This is the first model of co-induction of cMoat and GCS-HS genes in vivo in the mouse liver, associated with increased glutathione synthesis and biliary glutathione output. Our observations are consistent with the hypothesis that the cMoat transporter plays a crucial role in the secretion of biliary GSH. (+info)