Table 1. Widely different numbers of genes are differentially expressed in (A) C. elegans and (B) P. pacificus in response to the four bacteria.

(A) C. elegans	Up	Down	TOTAL	%Up	%Down
B. thuringiensis	5532	156	5688	97%	3%
S. aureus	181	68	249	73%	27%
S. marcescens	1465	4931	6396	23%	77%
X. nematophila	732	7884	8616	15%	85%

The genes were called differentially expressed on microarrays if the FDR corrected p-value was less than 0.05 and the absolute value of fold changes was greater than 1.42 (corresponding to log2 fold change of 0.5 where log2(1.42) = 0.5).