Identification and characterization of sugar transporter of cryptobia salmositica

초록

Protozoa having flagella belonging to the order Kinetoplastida are a unique group of microorganisms, distinguishable from other flagellates by the presence of a DNA-containing compartment of their mitochondrion called a kinetoplase. Among these flagellated protozoa Cryptobia salmositica, a hemoflagellate, is transmitted by the rhynchobdellid leech Piscicola salmositica. On the west coast of North America it cause cryptobiosis in economically important fishes (Oncorhynchus spp.). In order to clarify the sugar metabolism, the scaffold 107 from whole gene database was focused as sugar transporter named SGT107. SGT107 gene was isolated from total RNA of cultured Cryptobia salmositica using reverse transcription-polymerase chain reaction method. For the determination of transport function, the Xenopus oocyte expression system was employed. The SGT107 consists of 1545 base pairs that encode a 515 amino acid residue protein. Hydropathy analysis suggested that SGT107 possess 10 putative membrane-spanning domains. The SGT107 transport tritium labeled deoxyglucose (about 3.5 folds) with time-dependent manner and without sodium ion dependency. The kinetic and inhibitory experiment is necessary for more detail understand of Cryptobia salositica sugar metabolism.