The list of highly expressed cyst genes was significantly enriched

for the molecular function “”structural constituents of ribosomes”" (p = 3.15 × 10-28), as well as other cellular constituents and biological processes related to ribosome (p = 1.03 × 10-20) and ribonucleoprotein complex (p = 3.13 × 10-16). These three GO categories had the lowest probability values. Similar GO categories were identified among the 215 highest ranking trophozoite transcripts. “”Structural constituents of ribosomes”" was again the eFT-508 chemical structure top-ranking molecular function (p = 7.9 × 10-28) “”ribonucleoprotein complex”" (p = 2.9 × 10-17) and “”non-membrane bound organelle”" A-769662 in vitro (p = 1.2 × 10-11). In contrast to the overall functional similarity between cyst and trophozoite transcriptome, when considering only genes SAHA HDAC concentration with the highest mRNA level significant differences were apparent between cyst and trophozoite. In addition to ribosomal proteins, the annotation of the most highly expressed cyst transcripts includes several structural proteins and variant surface proteins (Table 1). Only one gene (ubiquitin) featured in the cyst and trophozoite list of highly expressed genes. These analyses reveal that in spite of the over-representation of ribosomal functions in both stages, the cyst and trophozoite transcriptome are not only quantitatively but also qualitatively different.

Table 1 Gene ID and annotation of 14 most expressed cyst and trophozoite genes cysts trophozoites gene ID annotation gene ID annotation GL50803_7110 ubiquitin GL50803_16044 hypothetical GL50803_135002 histone H4 GL50803_10919 ribosomal protein S10B GL50803_121046 histone H2B GL50803_17153 α11 giardin GL50803_9848 dynein light chain GL50803_31374 hypothetical GL50803_32146 α-tubulin

GL50803_31532 ribosomal protein L18a GL50803_135231 histone H3 GL50803_7110 ubiquitin GL50803_6430 14-3-3 protein GL50803_15228 ribosomal protein S15A GL50803_4812 Olopatadine β-giardin GL50803_116306 variant surface protein GL50803_16114 ribosomal protein L36-1 GL50803_35316 protein 21.1 GL50803_19182 hypothetical GL50803_31107 hypothetical GL50803_15046 ribosomal protein L26 GL50803_135002 histone H4 GL50803_137610 variant surface protein GL50803_32002 ribosomal protein L10 GL50803_136001 variant surface protein GL50803_6135* ribosomal protein S17 GL50803_16501 variant surface protein GL50803_35621 protein 21.1 Validation of microarray data The abundance of selected transcripts was further investigated with quantitative PCR. Equal portions of cDNA were amplified with primers specific for 10 G. lamblia genes (Table 2). The raw Crossing Point values are displayed in Table 3 together with the log2 of the cyst/trophozoite ratios. The ratios are generally in agreement with the microarray data presented in Figure 1 in showing negative values for most genes.