Telomerase is a ribonucleoprotein enzyme that can elongate telomeric DNA, which is thought to be required for the development of cellular immortality and oncogenesis in mammals. We examined telomerase activity in tissues and primary cultured lymphoid cells of adult penaeid shrimps. Using the telomeric repeat amplification protocol (TRAP), we studied the characteristics of a putative novel telomerase in Penaeus japonicus. This telomerase could be inactivated by heating or treatment with RNase A or proteinase K. At elongation, this telomerase required dATP, dGTP, and dTTP, but not dCTP, as substrates. Sequence analysis of the TRAP product revealed that this telomerase synthesized (TTAGG)(n) repeated sequences. The activity of this telomerase was decreased but still readily detectable in 100 ng of protein extract from lymphoid tissue. The telomerase activity was detected in all examined tissues including testis, ovary, lymphoid, heart, hepatopancreas, and muscle. The highest telomerase activity was in the extract of ovarian tissues. In primary cultured lymphoid cells, the telomerase activity was retained. Thus, primary cultured lymphoid cells of Penaeus japonicus possess one of the factors necessary for cell line establishment.

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The influence of different extraction solutions on the proteins extracted from rice grains was investigated. The largest amounts of salt-soluble proteins were extracted with solutions supplemented with Tris-HCl at pH 8.0. Rice allergens were analyzed by multiplex immunodetection. Except for -globulin extracted with the solutions at pH 8.0, which showed a low-molecularweight band besides the main band, no significant solution-dependent difference among the allergens was found. Total proteins were extracted with four kinds of solution. The extraction of the basic subunit of glutelin was found to be SDS-dependent, and more protein was obtained with extraction solutions supplemented with SDS. The contents of -globulin and -amylase/trypsin inhibitors were higher in the extracts without SDS than with SDS. We conclude from the present data that, in order to obtain comparable data from rice grain saltsoluble and total protein analyses, differences in the protein extraction efficiency of solutions used should be taken into consideration.