Search results for "ATRAZINE"
showing 10 items of 58 documents
Determination of pesticides in soil samples by solid phase extraction disks
1993
A systematic study comparing the methodology and analytical results obtained in an investigation of seven pesticide residues (Molinate, Atrazine, Carbofuran, Pirimicarb, Prometryn, Malathion and Tetrachlorvinphos) in soil samples is reported. Solid-phase extraction (SPE) using glass columns and 47 mm disks of octyl and octadecyl-bonded silica was used in the pesticide analysis. The best extraction efficiency and clearest extracts are obtained with C8 disks. The analyses were carried out by capillary gas chromatography with nitrogen and phosphorus detection. Recovery experiments were performed at ppb levels in spiked soil samples. The average recoveries of the compounds were 53–77%. Detectio…
Kinetics and metabolism of 14C-lindane and 14C-atrazine in early life stages of zebrafish (Brachydanio Rerio)
1990
Abstract Fertilized eggs, yolk sac larvae, and juveniles of zebrafish were exposed to 14C-lindane and 14C-atrazine under static conditions and the uptake was studied for a period of 48 hours. After 24 hours, a number of animals were transferred into pesticide-free running water and the elimination was examined for another 24 hours. The bioconcentration factors (BCFs) as well as the rate constants for uptake and elimination were calculated. Except for the lindane uptake by eggs and the atrazine uptake by juveniles, the steady state was reached within five hours. For all tested developmental stages the bioconcentration factor of lindane distinctly exceeded 100, whereas it was less than 10 in …
Horizontal gene transfer of atrazine-degrading genes (atz) from Agrobacterium tumefaciens St96-4 pADP1::Tn5 to bacteria of maize-cultivated soil
2005
International audience; The plasmid pADP1::Tn5 derived from pADP1[Atr(+)] carrying a TnS transposon conferring kanamycin and streptomycin resistances was constructed and introduced in Agrobacterium tumefaciens St96-4. This genetically modified strain was inoculated (similar to 108 cfu g(-1)) in potted soils planted with maize and treated or not with atrazine (1.5 mg kg(-1)). Bulk and maize rhizosphere soils were sampled 39 days after planting to look for soil indigenous bacteria that had acquired pADP1::Tn5. Four transconjugants were isolated from four different soil samples. The estimated transfer frequency of pADP1::Tn5 was 10(-4) per donor. Maize rhizosphere and atrazine treatment had no…
Response of soil bacterial community structure to successive perturbations of different types and intensities
2008
SummaryIn soil, genetic structure modifications of indigenousbacterial community consecutively to a severe stress(mercury contamination) were delayed when thecommunity was pre-exposed to various minor per-turbations (heat, copper and atrazine). Such minorperturbations induced transitory community struc-ture modifications leading to an increase of commu-nity stability towards a severe mercury stress. Theseresults illustrated well the short-term pre-adaptationprocess for bacterial community hypothesizing thatcommunity submitted to perturbations become moreresistant to withstand another stress. Compared with other environmental matrices of the bio-sphere, soils are considered as the main reservo…
Effect of primary mild stresses on resilience and resistance of the nitrate reducer community to a subsequent severe stress
2008
International audience; The factors regulating soil microbial stability (e.g. resistance and resilience) are poorly understood, even though microorganisms are essential for ecosystem functioning. In this study, we tested whether a functional microbial community subjected to different primary mild stresses was equally resistant or resilient to a subsequent severe stress. The nitrate reducers were selected as model community and analysed in terms of nitrate reduction rates and genetic structure by narG PCR-restriction fragment length polymorphism fingerprinting. Heat, copper and atrazine were used as primary stresses and mercury at a high concentration as a severe stress. None of the primary …
Genetic rearrangement of the atzAB atrazine-degrading gene cassette from pADP1::Tn5 to the chromosome of Variovorax sp. MD1 and MD2
2007
International audience; We report the characterization of the rearrangement phenomena responsible for the movement of the atrazine-degrading atzA and B genes from pADP1::Tn5 to the chromosome of Variovorax sp. MD1 and MD2. Long PCRs and Southern blot analyses revealed that the two genes forming a gene cassette moved in a unique rearrangement event. It also revealed that the boundaries of the plasmid sequence inserted in the chromosome correspond to IS1071or to sequences close to IS1071. It suggests that this genetic rearrangement could result from the transposition of the composite transposon delimited by IS1071 insertion sequences and containing atzA and atzB genes. In addition, for MD1 an…
Isolation and characterisation of Nocardioides sp. SP12, an atrazine-degrading bacterial strain possessing the gene trzN from bulk- and maize rhizosp…
2003
International audience; We report the characterisation of Nocardioides sp. SP12, an atrazine-degrading bacteria isolated from atrazine-treated bulk- and maize rhizosphere soil. Based on 16S rDNA alignment, strain SP12 showed close phylogenic relationships with Nocardioides sp. C157 and Nocardioides simplex. Internal transcribed spacer (ITS) sequences of strain SP12 were longer than those of other Nocardioides sp. and present Ala- and Ile-tRNA unlike Actinomycetales. Nocardioides sp. SP12 presents a novel atrazine catabolic pathway combining trzN with atzB and atzC. Atrazine biodegradation ends in a metabolite that co-eluted in HPLC with cyanuric acid. This metabolite shows an absorption spe…
Dissipation and distribution of atrazine, simazine, chlorpyrifos, and tetradifon residues in citrus orchard soil.
1997
An environmental fate study was conducted in a citrus orchard plot in Valencia (Spain) in the fall of 1993. Dissipation and distribution of atrazine, simazine, chlorpyrifos and tetradifon residues following their controlled addition for agricultural purposes in a mediterranean red soil (Luvic Calcisol, Rhodoxeralf) were evaluated. During a two-month period, the amounts of applied pesticides in different soil layers (0-0.05, 0.05-0.22, 0.22-0.42, and 0.42-0.52 m) were monitored. In addition, information on soils, weather and agricultural practice were collected. Degradation half-lives were calculated, assuming zero-order kinetics: 11 days for atrazine, 12 days for simazine, 10 days for chlor…
Toxicity of lindane, atrazine, and deltamethrin to early life stages of zebrafish (Brachydanio rerio).
1990
Fertilized eggs of zebrafish were exposed under flow-through conditions to several concentrations of the following pesticides: lindane 40, 80, 110, 130, and 150 micrograms/liter; atrazine 300, 1300, and 9100 micrograms/liter; deltamethrin 0.5, 0.8, and 1.2 micrograms/liter. Hatching, abnormalities in development (external deformations, edema, etc.), and mortality were recorded over a period of 35 days. At the end of the experiment, the body lengths of the fish were measured. Survival of juvenile fish after 35 days was reduced by increasing concentrations of all xenobiotics tested: lindane enhanced the mortality from 110 micrograms/liter and atrazine from 1300 micrograms/liter, and deltameth…
In vivo genotoxicity of selected herbicides in the mouse bone-marrow micronucleus test
1997
The herbicides alachlor, atrazine, terbuthylazine, gluphosinate-ammonium, isoproturon, pendimethaline and trifluralin were tested for genotoxicity in the mouse bone-marrow micronucleus test (MNT). Both atrazine and trifluraline caused a significant increase in the number of micronuclei at doses of 1,400 mg/kg body weight in female mice only. Alachlor, terbuthylazine, gluphosinate-ammonium, isoproturon and pendimethaline did not have any genotoxic effect in the mouse bone-marrow micronucleus test in either female or male animals.