Expression profiles of select genes in C. parvum-infected HCT-8 cells. The expression level of each gene is calculated as the ratio of its RT-PCR product to that of C. parvum 18s rRNA. (a) glucose-6-phospate isomerase; (b) leucine aminopeptidase; (c) pteridine transporter (BT-1); (d) tyrosyl-tRNA synthetase; (e) calcium-dependent protein kinase; (f) dihydrofolate reductase-thymidine synthetase (DHFR-TS). The genes examined in (a-c, e) represent transferred genes of different origins; (d, f) represent non-transferred references. Error bars show the standard deviation of the mean of six independent time-course experiments.