Amino Acids herbicides, detection

Orejuela, E., and Silva, M., Rapid and sensitive determination of phosphorus-containing amino acid herbicides in soil samples by capillary zone electrophoresis with diode laser-induced fluorescence detection. Electrophoresis, 26, 4478, 2005. 

Molina, M. Silva, M. Analytical potential of fluorescein analogues for ultrasensitive determinations of phosphorus-containing amino acid herbicides by micellar electrokinetic chromatography with laser-induced fluorescence detection. Electrophoresis 2002,23,1096-1103. 

This approach has been used primarily to study photosynthesis, for example to introduce tolerance to a variety of stress conditions. Many studies have been successful in verifying the effea of single amino acid modifications on herbicide binding affinity. High affinity binding to the D1 protein is a useful property for the detection of herbicides. A fluorescence biosensor based on mutants resistant to various herbicide subclasses was developed, it makes possible to distinguish between subclasses of herbicides (e.g., triazines from urea and phenolic type herbicides). ... 

The specificity of the whole cells and isolated photosynthetic materials was obtained by applyir the knowledge available on the relationships between herbicide binding activity and the structure of the D1 protein. For example, distinctions among classes of chemicals could be achieved through mutations in amino acid residues of D1 which can impart resistance to individual triazine herbicides. Realisation of new, sophisticated transduction systems based on printed electrodes, fluorescence and chemiluminescence as well as alternative systems such as the reconstimtion of Qp site in overexpressed DI protein utilizing chromophore quinones to enhance sensitivity and specificity for detected signals. 

IPBC and glyphosate plus the herbicide atrazine (Tierney et al. 2007). After 30 min of exposure, all three pesticides eliminated the attraction behavior to L-histidine. The chemicals also reduced the EOG response to the amino acid. Interestingly Roundup was also detected by the olfactory sense and a behavioral response to the pesticide was observed. 

In phase four, a method will be developed for determination of glyphosate, a herbicide, in soybeans. Glyphosate is an extremely small, very polar molecule containing an amino acid moiety, which may hamper EIA detection. Development of a method for soybeans will provide an indication of the degree of fficulty in EIA determination of residues in fatty foods, which require significantly more cumbersome and time-consuming extraction and cleanup steps for determination by chromatographic approaches. 

M. Molina and M. Silva, In-capillary derivatization and analysis of amino acids, amino phospho-nic acid-herbicides and biogenic amines by capillary electrophoresis with laser-induced fluorescence detection. Electrophoresis, 23, 2333-2340, 2002. 

The antibiotic activity may be offset by the addition of (L)-glutamine. All the other natural amino acids show no such effect. If Bacillus subtilis is cultivated with glutamine as the only carbon source, even at a 250-times higher than the normally active concentration of phosphinothricylalanylalanine, no inhibition is detectable. This leads to the conclusion that glutamine synthase is affected. To exhibit its herbicidal activity, the tripeptide has to be hydrolysed in vivo [ 12 ], and thereby releases phosphinothricin as the actual blocking agent of glutamine synthase. 

FIuazifop (2-[4-(5-trifluoromethyl-2-pyr1dyloxy)phenoxy]propionate) is a grass-specific herbicide. It is an aryloxyphenoxypropionate compound and these herbicides have been shown to kill sensitive species by causing necrosis of meristematic tissues. A number of studies on the mode of action of the aryloxyphenoxypropionates have only been able to demonstrate an inhibition of lipid metabolism. No detectable effects on CO2 fixation or carbohydrate, amino acid or nucleic acid metabolism have been shown ( Walker 1988a,). Cyclohexanedione herbicides, such as sethoxydim,... 

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