Empirical and physiological assessment of in vitro growth in the mermithid nematode Romanomermis culicivorax

In vitro growth of R. culicivorax preparasites was monitored in 2 culture media under differing conditions of crowding. Crowding was more important that the character of the medium itself in stimulating in vitro growth. The glycogen, protein, and lipid content of nematodes that had developed after 5 weeks under crowded conditions was significantly greater than that of uncrowded nematodes. The lipid content of such crowded nematodes was greater than that of nematodes after 4 days of in vivo development in larvae of Aedes aegypti, although glycogen and protein levels were lower than the 4 day in vivo norm. Nematodes that had developed in vitro contained a higher proportion of long-chain and polyunsaturated fatty acids than did nematodes cultured in vivo. The significance of these findings is discussed in relation to the establishment of a continuous in vitro culture system for this nematode..