Submitted to: Journal of Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/1999
Publication Date: 1/31/2000
Citation: Siegel, J.P., Smith, A.R., Novak, R.J. 2000. Cellular fatty acid analysis of isolates of bacillus thuringiensis serovar kurstaki, strain hd-1. Journal of Biological Control. Volume(17):82-91.
Interpretive Summary: Bacillus thuringiensis serovar kurstaki HD-1 (Bt) is a bacterium that is grown commercially for use as an insecticide. The purpose of this research was to determine if commercially produced Bt could be fingerprinted so that it could be distinguished from naturally occurring Bt. These data would aid in determining the environmental fate of insecticides using this bacterium. Fingerprinting commercial products as well as Bt deposited in public collections was accomplished using a technique known as Cellular Fatty Acid analysis, based on Gas-Liquid Chromatography (GLC). A database of these fingerprints was assembled and the relationship between commercial products and material from the public collections was evaluated statistically. We concluded that HD-1 is a mixture of fatty acid strains. These strains were different from those recovered in non HD-1 Bt insecticides. We conclude that CFA analysis may be used to identify commercial products.
Technical Abstract: Whole cell cellular fatty acid (CFA) composition was utilized to determine if Bacillus thuringiensis serovar kurstaki (HD-1) larvicides produced by different manufacturers could be distinguished from each other and to determine whether these larvicides were distinguishable from isolates deposited in public collections. Isolates of HD-1 deposited in the collections of the American Type Culture Collection, Bacillus Genetic Stock Center, Pasteur Institute and United States Department of Agriculture, as well as the 1971 and 1980 Standards of HD-1 were also analyzed. The data were grouped by hierarchical cluster analysis based on the unpaired-group method using arithmetic averages (UPGMA). Isolates of HD-1 from commercial products and deposits of HD-1 in the public collections and Standards were polytypic; 22 separate strains were identified in the 1971 and 1980 Standards and 35 strains were identified in the public collections. The type strain for Btk was polytypic; three strains were present in both the Bacillus Genetic Stock Center and Pasteur Institute collections. In contrast, the type strain in the USDA collection (HD-73) was monotypic and unique. We could distinguish between HD-1 and non HD-1 larvicides using CFA composition. We conclude that CFA analysis may be used to identify commercial products.