Meeting Abstract
P1.13 Jan. 4 Oxidative Signaling in Metamorphosis of a Gastropod KONDRACKI*, M.A.*; SEVERI, K.E.; PIRES, A.; Dickinson College; Dickinson College; Dickinson College kondracm@dickinson.edu
Reactive oxygen species are usually associated with cellular injury, however they may also act as components of signal transduction systems. Earlier work with the nudibranch, Phestilla sibogae, showed that treatment of metamorphically-competent larvae with H2O2 leads to loss of the larval velum, an important feature of metamorphosis. In the present study we determined that 10-4 M H2O2 also caused loss of velar cell adhesion in intact larvae and isolated velar lobes of the caenogastropod, Crepidula fornicata. We exploited the large size and extremely rapid metamorphosis of this species to ask if endogenous reactive oxygen species are generated in the velum during natural metamorphosis. Intact larvae were loaded with the oxidant probe, 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA). They then metamorphosed in the presence of the natural inducer derived from conspecific adults. Intense labeling of oxidative activity in freshly-shed velar lobes was confined to the large preoral ciliated cells that line the margin of the velum, and are the first to detach in metamorphosis. These cells remained viable after metamorphosis, metabolizing calcein AM and excluding ethidum homodimer-1. Naturally-metamorphosing H2DCFDA-loaded larvae were imaged with laser-scanning confocal microscopy, which revealed intense oxidative activity in the preoral ciliated cells before their detachment from the velum. Such labeling was absent in swimming and crawling control larvae. Current experiments seek to characterize the reactive oxygen species that may mediate loss of cell adhesion in metamorphosis. Supported by NSF award IBN-0110832 to A.P.
