#Freshwater fish parasite identification full#

1 and supplemental material ), suggesting that this gene might encode an enzymatically inactive product. cruzi Tyr342 and Trp312, among others ( 4, 6) (see Fig. Some residues critical for the catalytic activity are not conserved, like the ones corresponding to T. The deduced TcaTS protein is predicted to have a signal peptide cleavage site between residues 22 and 23 ( 15 ), and a GPI anchor signal (Fig. AY142111) was compared with that of the gene coding for T.

#Freshwater fish parasite identification full#

The translated full sequence of the tcats gene (GenBank accession no. Using the sequence information present in clone 05b16, we designed oligonucleotide primers to amplify the missing 5′ region and to confirm and extend the sequence of the 3′ region of the putative T. Clone 05b16 contains part of the C-terminal lectin-like domain of the gene. BU096369) that showed significant similarity (E = 10 −16, 37% identity for the best hit) to members of the T. In our EST data set, we found one clone (05b16 GenBank accession no. carassii trypomastigote extract has TS activity similar to those described in T. This confirms that the negative charge of the reaction product is due to the transfer of a sialic acid residue from the donor to the labeled lactose acceptor, indicating the presence of a transferase activity in the parasite extracts. Neuraminidase treatment of the purified reaction product prevented its interaction with a QAE-Sephadex resin and thus resulted in a decrease of radioactivity in this fraction (Table 2). The parasite extract contained an activity that was able to transfer sialic acid from sialyllactose to a lactose acceptor. TS activity was measured essentially as described in reference 19. TS activity was assayed with extracts from lyophilized T. Hence, we investigated whether TS activity was present in T. However, the trypanosomes studied so far do not synthesize sialic acid de novo but acquire it from the medium by using the enzyme TS ( 9). carassii have mucin-like surface molecules that are sialylated, as is the case in T.