Fig. 4. D. antillarum response to experimental ciliate challenge.

(A) Proportion of observed grossly normal urchins in control (both <5-μm filtrate and DI water treatments; open circles) and ciliate-challenged treatments (gray circles) following experimental inoculation. (B) Philaster-like 28S rRNA abundance determined by qPCR in discarded spines of ciliate-treated or control urchins at 24, 72, 84, 111, and 168 hours after inoculation. ND, not detected; X, specimen terminated due to spine loss; /, specimens not available because of prior termination; blank indicates no lost spines. Philaster-like 28S rRNA abundance in dissected tissues of terminated specimens (C) and in >0.2-μm aquarium water particulate matter (D) of grossly normal (open box) and abnormal (gray box), ciliate-inoculated urchins. No ciliates were detected in body compartments of any of the control specimens by histopathology.