Browsing by Author "Clark, BW"

Now showing 1 - 4 of 4
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    Environmental fate and effects of Bacillus thuringiensis (Bt) proteins from transgenic crops: a review.
    (Journal of agricultural and food chemistry, 2005-06) Clark, BW; Phillips, TA; Coats, JR
    This paper reviews the scientific literature addressing the environmental fate and nontarget effects of the Cry protein toxins from Bacillus thuringiensis (Bt), specifically resulting from their expression in transgenic crops. Published literature on analytical methodologies for the detection and quantification of the Cry proteins in environmental matrices is also reviewed, with discussion of the adequacy of the techniques for determining the persistence and mobility of the Bt proteins. In general, assessment of the nontarget effects of Bt protein toxins indicates that there is a low level of hazard to most groups of nontarget organisms, although some investigations are of limited ecological relevance. Some published reports on the persistence of the proteins in soil show short half-lives, whereas others show low-level residues lasting for many months. Improvements in analytical methods will allow a more complete understanding of the fate and significance of Bt proteins in the environment.
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    Subacute effects of transgenic Cry1ab Bacillus thuringiensis corn litter on the isopods Trachelipus rathkii and Armadillidium nasatum.
    (Environmental toxicology and chemistry / SETAC, 2006-10) Clark, BW; Prihoda, KR; Coats, JR
    Laboratory studies were conducted to investigate the subacute effects of transgenic Cry1Ab corn leaf material containing Bacillus thuringiensis (Bt) protein on the terrestrial isopods Trachelipus rathkii and Armadillidium nasatum. Survival and growth were measured for eight weeks in isopods fed leaf material of two Bt11 corn varieties, two Monsanto 810 (Mon810) corn varieties, and the isolines of each. Total lipid and protein content of the organisms was measured to examine effects on energetic reserves. Armadillidium nasatum individuals in all treatments responded similarly. For T. rathkii, no statistically significant effect of Bt was observed, but statistical differences were observed in growth between hybrids. Protein and sugar content of the food were found to be correlated with the differences in growth for T. rathkii. Total protein content was higher in T. rathkii and A. nasatum fed material with higher protein and sugar content. A trend toward less growth in T. rathkii on Bt corn varieties versus their isolines triggered a concentration-response assay with purified Cry1Ab protein. No adverse effects of purified Bt protein were observed. These results indicate that little hazard to T. rathkii and A. nasatum from Bt corn leaf material from these hybrids exists. However, nutritional differences in corn hybrids contributed to differences in isopod growth.
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    Toxicity of pendimethalin to nontarget soil organisms.
    (Bulletin of environmental contamination and toxicology, 2005-04) Belden, JB; Phillips, TA; Clark, BW; Coats, JR