11th ICRS Abstract book - Nova Southeastern University

7-21
Coral Host Processes Associated With Disease Pathology And Patterns Of Tissue
Loss.
Tracy AINSWORTH* 1
1 ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville,
Australia
Recent advances in sequencing cnidarian transcriptomes have revealed the unexpected
genetic complexity of these morphologically simple basal organisms and have the
potential to provide novel insights into the biology of these economically and
ecologically important organisms. The emerging insights into cnidarian genomics provide
the opportunity to develop an array of tools that can be applied to better understand the
physiology, molecular biology and cellular responses of corals, and also to improve our
understanding of the pathological changes that are seen on coral reefs today. Patterns of
disease, tissue loss and bleaching have been described on coral reefs worldwide and
appear to be increasing under increased environmental pressures. The apparent link
between environmental stress and degraded coral health, and the recent information
demonstrating the complexity of the cnidarians, highlights the need to understand the
biology of the coral host and host responses in these patterns of change. Here we combine
genome biology and pathology tools to investigate the host responses associated with
coral diseases. We outline the diversity of responses that occur at the molecular and
cellular level that are involved in different stages and types of disease and tissue loss. We
have identified the coral homologs of many of the key molecules that are involved in the
recognition of pathogen associated molecular patterns, in extrinsically and intrinsically
activated apoptotic pathways, and pro- and anti-apoptotic molecules in mammals. This
study demonstrates the complexity of the coral host biology associated with disease, and
highlights the requirement for better understanding of the underlying physiological
processes associated with coral diseases.
7-22
Natural Resistance To Disease in The Endangered Staghorn Coral acropora
Cervicornis
Steve VOLLMER* 1 , David KLINE 2
1 Marine Science Center, Northeastern University, Nahant, MA, 2 Centre for Marine
Studies, University of Queensland, St. Lucia, Australia
Disease epidemics are reshaping tropical coral reefs from the reef corals on up, and yet
we know very little about the abilities of the coral host to respond or resist disease
infection. Understanding the potential for natural disease resistance in corals is
particularly important in the Caribbean where the two ecologically dominant shallowwater
corals Acropora cervicornis and A. palmata have suffered an unprecedented
mass die-off due to White Band Disease and are now listed as threatened on the US
Endangered Species Act. We examined the potential for natural resistance to WBD in the
endangered staghorn coral Acropora cervicornis using in situ transmission assays and
field monitor of WBD on tagged staghorn coral genotypes and present evidence for the
occurence for WBD resistant genotypes. This WBD resistance demonstrates that staghorn
corals have an innate ability to respond to the WBD epidemic, and that the propagation of
WBD resistant genotypes can be used to facilitate the recovery of these endangered
corals.
Oral Mini-Symposium 7: Diseases on Coral Reefs
7-23
Differential Gene Expression Displayed By pocillopora Damicornis in Response To
Infection By vibrio Coralliilyticus
Angela POOLE* 1 , Sara EDGE 2 , Amy LANE 3 , Joshua VOSS 2 , Michael MORGAN 1
1 Berry College, Mount Berry, GA, 2 Harbor Branch Oceanographic Institute, Ft. Pierce, FL,
3 School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA
Coral degradation is occurring worldwide at an alarming rate and one of the contributors is the
increasing frequency and severity of disease. Previous studies have demonstrated that the coral
Pocillopora damicornis is susceptible to a temperature-dependent infection by the bacteria
Vibrio coralliilyticus, which induces both bleaching and lysis of the tissue. Molecular
investigations can provide additional information about the coral’s response to this infection. In
this project, RDA (Representational Difference Analysis) was used to detect differentially
expressed genes in P. damicornis as a result of the infection by V. coralliilyticus. Coral
samples were collected from Fiji in August of 2006 and exposed to V.coralliilyticus in the
laboratory. The RDA protocol successfully isolated 90 uniquely different gene fragments.
Results from Northern Dot Blot analysis have confirmed differential expression for several of
the isolated RDA products. Expression profiles for individual genes reveals that some of these
transcripts can also be detected in other diseased conditions. These results suggest that some of
these genes maybe useful biomarkers of disease pathology.
7-24
Pigmentation As Part Of A General Immune Response in Scleractinians
Caroline PALMER* 1,2 , John BYTHELL 1 , Bette WILLIS 2
1 School of Biology, Newcastle University, Newcastle, United Kingdom, 2 ARC Centre of
Excellence for Coral Reef Studies and School of Marine and Tropical Biology, James Cook
University, Townsville, Australia
The ability of hard coral to resist infection and to recover from injury remains poorly
understood, yet with the increase in coral disease and coincident global reef degradation, a
greater understanding of the immune capabilities of corals is becoming increasingly important.
Many invertebrates induce a basic inflammatory response to tissue invasion using the melanin
producing signalling pathway and phagocytosis to encapsulate and remove the invading foreign
organism. The presence of potential defence mechanisms in two different types of scleracatinian
coral, Acropora millepora and Porites sp. was investigated. Compromised tissue was
compared to healthy tissue using enzyme activation assays for the presence of the
phenoloxidase pathway. Histological samples of compromised and healthy tissue were taken to
assess differences at a cellular level using the Fontanna-Masson stain and cryo-histology. The
phenoloxidase pathway was found in healthy tissue of both A. millepora and the Porites sp.,
with an up-regulation in compromised tissue of A. millepora. Histological examinations show
reduced numbers of zooxanthellae in compromised tissue of both species. In addition,
investigations also suggest the presence of putative ameobocytes in both corals, conclusively
determined the presence and location of melanin in Porites sp., and the presence of a red
fluorescent protein responsible for the non-normal pigmentation observed macroscopically in
areas of wound healing. These results indicate that the prophenoloxidase pathway is activated in
compromised tissue of scleractinian coral, and suggest the presence of fluorescent proteins as
part of a generalised defence response to localised stress. This study demonstrates the presence
of general immune response mechanisms in scleractinian corals and also contributes to current
understanding of how differential development of innate immunity might influence ecological
and life history differences among coral species.
51