Viability, infectivity and fatty acid synthetic activity of Perkinsus marinus meront cells incubated in estuarine and artificial seawater.
We investigated the viability and fatty acid synthetic activity of in vitro cultured Perkinsus marinus (Dermo) in lipid-free medium and estuarine water, and the infectivity of P. marinus maintained in artificial seawater (ASW). Viability and fatty acid synthetic activity in 7 d old P. marinus meronts maintained in lipid-free medium and estuarine water were tested. The infectivity of meronts incubated in ASW was examined by first incubating P. marinus meronts in ASW for 2, 3 or 7 d, and then inoculating viable ASW-incubated meronts into the shell cavity of individual oysters Crassostrea virginica. P. marinus infection prevalence and intensity in oysters were determined 9 wk post-inoculation. Heavy mortality occurred in meronts maintained in estuarine water, a drop from an initial value of 100% viable to 7.8 and 6.1% after 3 and 14 d incubation, respectively. Viability was 85 and 67% in meronts maintained in lipid-free medium for 3 and 24 d, respectively. Meronts kept in lipid-free medium for 14 d retained their ability to synthesize fatty acids. Viable meronts incubated in ASW remained infective for up to 7 d. The infection prevalences were 85, 48 and 100%, in the treatments inoculated with viable meronts that were incubated in ASW for 2, 3 and 7 d, respectively. Infection prevalence in the group inoculated with viable meronts immediately after they were transferred to ASW ranged from 61 to 85%. Our results suggest that in nature meronts can survive for at least 14 d outside the host. Viable meronts are not only infective, but are also able to replicate and retain their fatty acid synthetic ability for 7 d.
Chu
Fu-Lin E
FL
Virginia Institute of Marine Science, College of William and Mary, Gloucester Point 23062, USA. chu@vims.edu
Lund
Eric D
ED
D000818:Animals; D002478:Cells, Cultured; D049896:Crassostrea / Q000469:parasitology*; D056890:Eukaryota / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*; D005227:Fatty Acids / Q000032:analysis / Q000096:biosynthesis*; D008018:Life Cycle Stages / Q000502:physiology; D012623:Seawater / Q000469:parasitology*; D013997:Time Factors
D005227:Fatty Acids