20uC. This helps remove the background of macromolecules not isolated from the intestine. The response to Cry5B is not altered in this strain compared to wild type [6] . Primers used for these experiments are described in Protocol S1. Approximately 15,000 L4 stage worms were used per 100 mm dish for each treatment group. Worms were exposed to Cry5B for the indicated period of time on either E. coli JM103 containing empty vector or E. coli JM103 expressing Cry5B as described [6, 38] . After exposure to each treatment, worms were rinsed from plates with water, centrifuged at 500 g for 45 seconds, and washed two additional times with water. RNA was prepared from worms using TRIZOL (Invitrogen) and further purified with RNeasy columns (Qiagen). cDNA was prepared by reverse transcription using oligo-dT. Standard PCR was used to detect xbp-1 splicing, and products were analyzed on 2% agarose gel. Unspliced xbp-1 transcript is 220 nucleotides and spliced transcript is 197 nucleotides. To quantitate the amount of xbp-1 splicing, loading was normalized by quantitating cDNA levels using real time PCR and eft-2 primers [6] . Equal amounts of cDNA were used for the xbp-1 splicing PCR experiments and 10 microliters of each reaction were loaded onto a 2% agaose gel and stained with ethidium bromide. NIH ImageJ was then used to quantitate the intensities of xbp-1 spliced forms in Cry5B treated samples relative to untreated samples at the same time point.