11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 5: Functional Biology of Corals and Coral Symbiosis: Molecular Biology, Cell Biology and Physiology
5-50
Cell-Death Pathways Associated With Vibrio Infection And Inhibition Of Heat
Shock Proteins And Apoptosis "Cell Death Signals"in Clade Subtypes A,b,c,d
James CERVINO* 1,2 , Nancy KRUCHER 1 , Konrad HUGHEN 3
1 Biological Sciences, Pace University, NY, NY, 2 Geochemistry, Woods Hole
Oceanographic Inst., Woods Hole, 3 Geochemistry, Woods Hole Oceanographic Inst.,
Woods Hole, MA
The biochemical impairment mechanisms associated with infection of Symbiodinium spp.
results in a reduction of protein synthesis within 4 hr of treatment in vitro. Heat shock
proteins (HSPs) are a family of highly conserved proteins found in cells that are induced
due to cell stress. We have found an HSP70-related protein in Symbiodinium (sub-type
C1) with an apparent molecular weight of 120-140kd using HSP70 specific antibodies.
This putative HSP70-related protein is expressed highly in CLADE C, at low levels in
CLADE A, but was not found in CLADES B and D, which is consistent with the
observed patterns of CLADE D and A sub-type thermal tolerance. Interestingly,
inoculation of Vibrio pathogens reverse the induction of the HSP70-related protein in
heat stressed (33oC) Symbiodinium CLADE C1. These data are also consistent with cellcycle
mitotic index impairment analysis. All Symbiodinium CLADE subtypes show a
decline in cell division following 48 hr treatment with Vibrio pathogens together with
thermal stress. HSP and cell-cycle inhibition are also consistant with Apoptosis markers
using Annexin V flouresence staining. Improperly regulated apoptosis is implicated
during the Vibrio induced disease states at higher temperatures. Thermally stressed cells
are detected by annexin V binding to externalized phosphatidylserine, however with
thermal stress together with Vibrio infection, the presence of phosphatidylserine is not
evident. These data support the recent findings and hypothesis that coral disease cell
death mechanisms follow a different cell-death process compared to thermal bleaching
mechanisms. Using Symbiodinium CLADE subtypes as in vitro models can also give
researchers and better understanding into cancer cell research that are associated with
bacterial infections.
38