Reference

Induction of wheat and maize glutathione S-transferase by some herbicide safeners and their effect on enzyme activity against butachlor and terbuthylazine

All Rights Reserved. Induction of wheat and maize glutathione S-transferase by some herbicide safeners and their effect on enzyme activity against butachlor and terbuthylazine. Scarponi, Luciano; Quagliarini, Elisa; Del Buono, Daniele ( Dipartimento di Scienze Agrarie e Ambientali, Universita degli Studi di Perugia, Perugia 06121, Italy). Pest Management Science, 62(10), 927-932 (English) 2006 John Wiley & Sons Ltd. CODEN: PMSCFC. 50812-37-8 and 103112-35-2 are cas registry numbers. These chemicals are also mentioned in this article. ISSN: 1526-498X. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemical Bioregulators) The expression of glutathione S-transferase (GST) activity in wheat and maize (corn) shoots was investigated in response to treatments with the herbicide safeners (protecting crops from adverse herbicide effects) benoxacor, cloquintocet-mexyl, fenchlorazole-Et, fenclorim, fluxofenim, and oxabetrinil. The safeners enhanced the GST activity towards 1-chloro-2,4-dinitrobenzene (CDNB, std. substrate), with the exception of oxabetrinil in maize. The enhanced GST (CDNB) activity was concomitant with increased Vmax (reaction rate when the enzyme is fully satd. with substrate) in wheat following cloquintocet-mexyl and fenchlorazole-Et treatments, and in maize following fenchlorazole-Et treatment. Decreased Vmax values were obsd. in wheat and maize with fenclorim and fluxofenim treatments. With the exception of oxabetrinil, all the safeners decreased the apparent KM (Michealis const.; substrate concn. for 50% of max. GST activity) of both wheat and maize GST. The Vmax and KM changes following safener treatments are discussed in terms of increased expression of GST enzymes and increased affinity for the CDNB substrate. The activity of wheat and maize GST was also assayed towards butachlor and terbuthylazine, resp. The results indicated the ability of cloquintocet-mexyl, fenchlorazole-Et, and fluxofenim to enhance the GST enzyme activity in wheat and of benoxacor and fenchlorazole-Et in maize. .

Influence of fenchlorazole-ethyl on the metabolism of fenoxaprop-ethyl in wheat, barley, and crabgrass

Influence of fenchlorazole-ethyl on the metabolism of fenoxaprop-ethyl in wheat, barley, and crabgrass. Yaacoby, Tuvia; Hall, J. Christopher; Stephenson, G. R.Several substances are used for example 66441-23-4 and 103112-35-2 which are their cas registry numbers. (Dep. Environ. Biol., Univ. Guelph, Guelph, ON N1G 2W1, Can.). Pestic. Biochem. Physiol., 41(3), 296-304 (English) 1991. CODEN: PCBPBS. ISSN: 0048-3575. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemical Bioregulators) Section cross-reference(s): 4 The safener, fenchlorazole-Et (ethyl-1-(2,4-dichlorophenyl)-5-trichloromethyl-1H-1,2,4-triazole-3-carbo xylate), eliminated and reduced, resp., the phototoxicity of the herbicide fenoxaprop-Et (ethyl-(±)2-[(6-chloro-2-benzoxazolyl)-oxy]phenoxy] propanoate) to wheat (Triticum aestivum) and barley (Hordeum vulgare). In barley the ED50 value for foliar-applied fenoxaprop-Et was 150 g ai/ha. In wheat an ED50 value could not be detd. because of its tolerance to the herbicide but there was a 30% redn. in dry wt. after application of 600 g ai/ha. In both wheat and barley no redn. in dry wt. occurred when the same resp. doses of the herbicide were applied in combination with the safener (4:1 wt./wt., herbicide:safener). Conversely, addn. of fenchlorazole-Et increased the toxicity of fenoxaprop-Et to crabgrass (Digitaria ischaemum). Metab. studies on foliar-applied [14C]fenoxaprop-Et indicated that the herbicide was dessterified to fenoxaprop in all three species. Regardless of whether the safener was present or not, three major metabolites, 6-chloro-2,3-dihydro-benzoxazol-2-one (HOE 054014), and two unidentified water-sol. metabolites, were found in wheat, barley, and crabgrass 48 h after treatment. When [14C]fenoxaprop-Et was applied alone, approx. 29, 63, and 9% of the applied radioactivity was metabolized to products other than fenoxaprop 48 h after treatment, whereas 48, 96, and 8% was metabolized when the safener also was applied to wheat, barley, and crabgrass, resp. Fenchlorazole-Et may protect barley and wheat from the phytotoxic action of fenoxaprop-Et by increasing both the rate of deesterification of fenoxaprop-Et to fenoxaprop and the rate of metab. of fenoxaprop to other metabolites. In crabgrass deesterification of and the rate of metab. of fenoxaprop to other metabolites. In crabgrass, deesterification of fenoxaprop-Et was increased by the safener but the subsequent detoxification of fenoxaprop was not increased in a manner similar to that found in the other two species. .