A standardized method of propagating the marine fish parasite, Amyloodinium ocellatum

The peridinian dinoflagellate Amyloodinium ocellatum was propagated by serial passage in clownfish (Amphiprion ocellaris) and hybrid striped bass (Morone chrysops X Morone saxatilis). Each 25-50-mm fish was exposed to 4,000-6,000 dinospores in 400 ml of artificial seawater for 30 min. Two days after exposure, trophonts were harvested by immersing the fishes in fresh water. After encystment, tomonts were axenized by multiple washes with sterile distilled water and sterile artificial seawater containing penicillin and streptomycin, and then incubated in the antibiotic solution. High yields of both tomonts and dinospores of the same sizes and ages were obtained, and host mortalities were eliminated. Microbial growth in incubating cultures was inhibited until after dinospores had emerged from tomonts, and dinospores remained infective for at least 4 days at 26 C.     

Birth defects in infants conceived by intracytoplasmic sperm injection: an alternative interpretation.

OBJECTIVE: To test the hypothesis that liveborn infants conceived by intracytoplasmic sperm injection are at an increased risk of having a major birth defect. DESIGN: Reclassification of the birth defects reported in infants born after intracytoplasmic sperm injection in Belgium and comparison with prevalence estimated in Western Australian population by means of same classification system. SETTING AND SUBJECTS: 420 liveborn infants who were conceived after intracytoplasmic sperm injection in Belgium and 100,454 liveborn infants in Western Australia delivered during the same period. MAIN OUTCOME MEASURES: Estimates of birth prevalence of birth defects and comparisons of odds ratios between cohort conceived after intracytoplasmic sperm injection and Western Australian infants. RESULTS: Infants born after intracytoplasmic sperm injection were twice as likely as Western Australian infants to have a major birth defect (odds ratio 2.03 (95% confidence interval 1.40 to 2.93); P = 0.0002) and nearly 50% more likely to have a minor defect (1.49 (0.48 to 4.66); P = 0.49). Secondary data-led analyses, to be interpreted with caution, found an excess of major cardiovascular defects (odds ratio 3.99), genitourinary defects (1.33), and gastrointestinal defects (1.84), in particular cleft palate (5.11) and diaphragmatic hernia (7.73). CONCLUSIONS: These results do not confirm the apparently reassuring results published by the Belgian researchers of intracytoplasmic sperm injection. Further research is clearly required. Meanwhile, doctors practising intracytoplasmic sperm injection should bear this alternative interpretation in mind when they counsel couples and obtain informed consent for the procedure.     

Propagation of the marine dinoflagellate Amyloodinium ocellatum under germ-free conditions

Germ-free infections of Amyloodinium ocellatum were produced on both living fish and in organ cultures. Exposing gnotobiotic guppies (Poecilia reticulata) to 125 dinospores in multiwell tissue culture plates produced nonlethal infections that could be serially propagated. Exposure to 250 or more parasites killed the fish during the first infection cycle, but if the dead fish were incubated in a cell culture medium/seawater mixture, the parasites could survive and reproduce for up to 2 wk in these organ cultures. Organ cultures containing only seawater or those containing bacteria did not support the prolonged survival of Amyloodinium.