Find in Library

Sexual stage induction under in vitro conditions is useful for biological and molecular studies of <i>Babesia</i> parasites. Therefore, in the present study, we induced <i>B. ovata</i> tick stages using the chemical inducers: xanthurenic acid (XA), dithiothreitol (DTT) and tris (2-carboxyethyl) phosphine (TCEP) at 27 &#176;C or 37 &#176;C conditions. Cultures at low temperature (27 &#176;C) or treated with XA/TCEP induced a large number of extra-erythrocytic merozoites, which transformed into round shape cells at 12&#8722;24 h post-induction (pi). However, typical forms of tick stages (aggregation forms and the spiky forms/ray bodies) were only observed in the cultures treated with 40 mM or 60 mM of DTT during 3&#8722;6 h pi. The induced cells were recognized by anti-CCp2 rabbit antisera. DNA content of the cell population treated with 40 mM of DTT was analyzed by imaging flow cytometry at 0, 12 and 48 h pi. The results indicated that the parasite population with diploid-like double DNA content increased at 48 h pi. Our observations on morphological and changes in the DNA content provide useful information for understanding the life cycle of <i>B. ovata</i> under in vitro conditions, which will facilitate further studies on basic biology and the development of transmission blocking vaccines against bovine babesiosis.