Discussion

* This abstract/presentation is in memoriam to our wonderful and inspiring colleague Paula Ribeiro, who passed away. One of the fascinating features of schistosomes is that the sexual maturation of the adult female depends on a permanent pairing contact with the male. Although males appears sexually mature before pairing, male-female interaction of schistosomes seems to be a bidirectional process. Although a number of studies have addressed this in the past, our knowledge about this part of schistosome reproductive biology and the underlying molecular principles is still fragmentary. By organ-isolation and subsequent comparative sub-transcriptomics with RNA of gonads from both paired and unpaired adult S. mansoni, we identified transcripts of >7,000 genes in both sexes. Of these, many transcripts occurred pairing-dependently, 3,600 in ovaries and 243 in testes. Besides evolutionary aspects, bioinformatics provided new insights into the potential roles of kinases, GPCRs, and neuropeptides in schistosome development and differentiation. Evidence was obtained for a prominent role of kinases for female traits, whereas part of the GPCRs and neuropeptides may be involved in male-associated, gonad-independent processes. Furthermore, male-female interaction even influences neural activities in females, which downregulate the expression of some GPCR and neuropeptides following pairing. The obtained results suggest that the male-female interaction of schistosomes is more complex than envisaged before.