[CDHC] Announcing New Paper: Symbiophagy as a cellular mechanism for coral bleaching

[Cheryl Woodley]

Dear CDHC List Members
Happy New Year...
I would like to let you know of a new publication co-authored by several 
CDHC members. The citation and abstract is provided below.
I would also like to encourage each of you having new papers coming out 
to post the information to the list.
All the best
Cheryl

Autophagy 5:2, 211-216; 16 February 2009]

Symbiophagy as a cellular mechanism for coral bleaching
Craig A. Downs, Esti Kramarsky-Winter, Jon Martinez, Ariel Kushmaro, 
Cheryl M. Woodley, Yossi Loya and Gary K. Ostrander

Abstract
Coral bleaching is a major contributor to the global declines of coral 
reefs. This phenomenon is characterized by the loss of symbiotic algae, 
their pigments or both. Despite wide scientific interest, the mechanisms 
by which bleaching occurs are still poorly understood. Here we report 
that the removal of the symbiont
during light and temperature stress is achieved using the host’s 
cellular autophagic-associated machinery. Host cellular and subcellular 
morphologies showed increased vacuolization and appearance of autophagic 
membranes surrounding a variety of organelles and surrounding the 
symbiotic algae. Markers of autophagy (Rab 7 and LAS) corroborate these 
observations. Results showed that during stress the symbiont vacuolar 
membrane is transformed from a conduit of nutrient exchange to a 
digestive organelle resulting in the consumption of the symbiont, a 
process we term symbiophagy. We posit that during a stress event, the 
mechanism maintaining symbiosis is destabilized and symbiophagy is 
activated, ultimately resulting in the phenomenon of bleaching. 
Symbiophagy may have evolved from a more general primordial innate 
intracellular protective pathway termed xenophagy.


-- 
Cheryl Woodley, Ph.D.
Coral Health and Disease Program

DOC/NOAA/NOS/NCCOS
Center for Coastal Environmental Health and Biomolecular Research
Hollings Marine Laboratory
331 Fort Johnson Rd
Charleston, SC 29412
843.762.8862 Phone
843.762.8737 Fax
cheryl.woodley at noaa.gov