TgESTzyf11b03.y1 TgME49 B7 Tachyzoite cDNA Library 1 Toxoplasma gondii cDNA clone TgESTzyf11b03.y1 5' similar to SW:DRTS_TOXGO Q07422 BIFUNCTIONAL DIHYDROFOLATE REDUCTASE-THYMIDYLATE SYNTHASE, mRNA sequence