Cellular Fatty-Acid Analysis of Bacillus thuringiensis Var. kurstaki Commercial Preparations

Abstract

Cellular fatty acid (CFA) composition of Bacillus thuringiensis var. kurstaki (Btk) preparations was determined by use of the MIDI Sherlock microbial identification system on a Hewlett-Packard 5890 gas chromatograph. Four commercial preparations--one Btk sample obtained from the U.S. Forest Service, one Btk sample obtained from Dugway Proving Ground, and Btk and Bacillus thuringiensis var. israelensis (Bti) preparations obtained from American Type Culture Collection (ATCC)--were analyzed and evaluated. This study demonstrated the capability to detect the strain variation in the bacterial species Btk and to clearly differentiate strain variants on the basis of qualitative and quantitative differences in hydrolyzable whole CFA compositions in the preparations examined. We conclude that CFA analysis may be used to identify commercial products but that a more intensive study would be required to evaluate the potential of CFA to provide an inexpensive screening tool applicable to several levels of isolate or product evaluation, including how applied preparations might interact with natural populations over time.

The Detection of Bacillus thuringiensis in Mass Rearing of Cactoblastis cactorum (Lepidoptera: Pyralidae)

“…kurstaki. The inability of this method to place this isolate close to known B. thuringiensis may reflect the wide variation among different Bt isolates and/or the fact that the precision of MIDI is reliant on a high stringency of method standardization (Adams et al 2005). The association of Bt isolates with B. cereus subgroup A is in agreement with the results of both MIDI and sequence analyses that have been conducted on this bacterial group (Wintzingerode et al 1997;Bavykin et al 2004).…”

A Novel Radiation-Resistant Strain of Filobasidium sp. Isolated from the West Sea of Korea

“…Fatty acid analysis. The cellular fatty acid (CFA) composition of the RRY1 strain was determined using a standard protocol of the MIDI/Hewlett Packard Microbial Identification System [1], in which fatty acid methyl esters of freeze-dried yeast cells (unirradiated or irradiated at 3 kGy) were extracted after saponification and methylation, and then analyzed by gas chromatography. The Agilent 6890N GC system (Agilent Technologies Inc., DE, USA) with a methyl phenyl silicone fused silica capillary column (HP 19092B-102) and flame ionization detector (FID) (carrier gas: H 2 ; initial temperature: 170 o C; final temperature: 270 o C; FID temperature: 300 o C; injection port temperature: 250 o C) was used for the analysis.…”

Identification of airborne bacteria by 16S rDNA sequencing, MALDI-TOF MS and the MIDI microbial identification system

“…In addition to identification, FAME analysis has been used for strain or subspecies level comparisons (Van den Velde et al 2006). Previously, the MIDI MIS system has been successfully utilized for the differentiation of various strains of Bacillus thuringiensis (Adams et al 2005). The cellular fatty acid profiles of 67 strains belonging to three different species of the genus Mycobacterium have been determined from clinical samples (Ozbek and Aktas 2003).…”