ABSTRACT
As larval trematodes live within tissues of their molluscan hosts and indulge in asexual reproduction on a phenomenal scale, it is not surprising that snail tissues show biochemical changes. Levels of tissue glycogen, lactate, pyruvate and LDH[1] isoenzyme were measured in extracts of whole soft tissues of Biomphalaria alexandrina snails, specific molluscan hosts of Schistosoma mansoni. Moreover, assay of adenine nucleotides [ATP, ADP and AMP] and inorganic phosphate [Pi] was established to evaluate the adenylate energy charge [AEC] and the phosphate potential in trematode-infected snails. These parameters were measured in infected snails over four weeks, at weekly interval post exposure to S. mansoni miracidia and compared to age-matching non-exposed snails. The highest lactate/pyruvate concentration ratio with the lowest LDH[1], isoenzyme activity and glycogen level were observed two weeks post exposure. In addition, the lowest ATP content, ATP/ADP and ATP/AMP concentration ratios were also recorded at the same duration post exposure. The energy charge does not co-vary with ATP level but was slightly manipulated within the non-stressed range, while phosphate potential as a direct measure of oxygen consumption was significantly altered within 1[st], 2[nd] and 3[rd] weeks post exposure. This study clarify the most characteristic pattern of changes induced by the developing parasite. Moreover it reflects the need for an efficient glycolytic flux in the B.alexandrina snails to ensure survival and further development of S mansoni parasite