11th ICRS Abstract book - Nova Southeastern University

7.199
Antibacterial Chemical Defenses in Corals: Widespread But Selective Resistance
To Bacterial Pathogens
Deborah GOCHFELD* 1,2 , Greta S. AEBY 3 , Katerina PAPPAS 1
1 National Center for Natural Products Research, University of Mississippi, University,
MS, 2 Environmental Toxicology Research Program, University of Mississippi,
University, 3 Hawaii Institute of Marine Biology, Kaneohe, HI
One potential mechanism of resistance to disease in corals is the production of
antibacterial chemical defenses that protect corals from bacterial pathogens. In an effort
to determine whether corals produce antibacterial chemical defenses, we have tested
aqueous extracts from Caribbean and Pacific corals in bacterial growth assays using a
series of test strains including known coral pathogens, potential marine pathogens found
in human waste and bacteria previously identified from the surfaces of corals. Extracts
from all three species of Hawaiian corals exhibited high levels of antibacterial activity.
This activity varied at the coral colony, population and species level, and the activity was
highly selective against different bacterial strains, rather than broad-spectrum in nature.
In addition, some extracts were stimulatory to certain bacteria. Caribbean corals also
exhibited widespread antibacterial activity against the strains tested, and these were also
highly selective in their activity against different bacterial strains. Extracts from several
Caribbean species, however, stimulated the growth of Caribbean coral pathogens,
providing evidence for a correlation between coral chemical defenses and disease
incidence. Antibacterial chemical defenses clearly have the potential to provide corals
with protection from bacterial pathogens. The high degree of selectivity observed is
necessary so that the coral can maintain its naturally associated microbial community, yet
still ward off potentially harmful bacteria. Differences in levels or types of antibacterial
chemical defenses may represent a mechanism by which variability in resistance or
susceptibility to pathogens might be realized and may provide insight into patterns of
disease incidence and prevalence on coral reefs.
7.200
Optimization Of Bacterial Challenge Protocols For Study Of montipora White
Syndrome
Teresa LEWIS* 1 , Megan COLVIN 1 , Ashley SMITH 1 , Greta AEBY 1 , Thierry WORK 2 ,
Jo-Ann LEONG 1
1 Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI,
2 USGS-BRD-NWHC, Honolulu, HI
Laboratory studies characterizing coral bacterial pathogens provide an essential
foundation for moving coral disease from descriptive nomenclature (i.e., white
syndromes) into identification of putative etiological agents. While a number of methods
have been published to test Koch’s Postulate’s, none have been applied for coral disease
research in Hawaii. Montipora white syndrome is a disease recently described in Hawaii
involving tissue loss. Developing a model for disease transmission studies using methods
described by others has led to some interesting observations, the most prominent being
the need to verify methods for each species of coral under study to account for
differences in physiology and adaptability to stress. “Model” bacteria isolated from M.
capitata associated with healthy (Alteromonas sp.) and diseased coral mucus (Vibrio
parahaemolyticus) were used in pilot studies to optimize methods for future bacterial
challenge experiments. Growth curves in Glycerol Artificial Seawater (GASW) and
sterile filtered seawater (FSW) established both bacteria capable of growing to log phase
in GASW but not FSW. Corals were fragmented and recovered in water tables with
flow-through conditions for one week, then placed in triplicate in static aquaria
containing FSW and provided aeration. Log phase Alteromonas or Vibrio cultures were
inoculated into the water or directly onto exposed surfaces of corals and after two hours
the water level was raised. Corals were monitored for two weeks, photographed, and
sampled periodically. At the end of the study no signs of disease at gross or microscopic
levels were observed. Analysis of mucus plated onto GASW agar at the conclusion of
experiments showed significant elevation of colonization of Alteromonas or Vibrio
without any disease signs. This study highlights the need for stringent validation of
bacterial challenge models for coral disease and continued refinement of methods.
Funding: NOAA/HCRI-RP grant #NOA06NOS4260200
Poster Mini-Symposium 7: Diseases on Coral Reefs
7.201
Parrotfish As Vectors Of Coral Disease - Evaluation By Comparison Of Bacterial
Populations
Christopher SHERIDAN* 1 , John C BYTHELL 2 , Reia GUPPY 2 , Randi D ROTJAN 3
1 School of Marine Science and Technology, Newcastle University, Newcastle, United
Kingdom, 2 School of Biology, Newcastle University, Newcastle Upon Tyne, United Kingdom,
3 Department of Organismc and Evolutionary Biology, Harvard University, Cambridge, MA
The role of parrotfish as bio-eroders and grazers is well described, but examination of bacterial
communities associated with parrotfish-inflicted lesions and parrotfish jaws suggest that they
may also act as vectors of coral pathogens. The microbiological and genetic analyses of these
microbial communities suggested a potential exchange of micro-organisms between parrotfish
jaws and bites taken from live coral. However, the defence mechanisms of corals seemed
sufficient to prevent both the penetration of these microbes within their tissues, and the
resulting disease causation. Mucus secretion in particular appeared to be the predominant
defence response to injury and possibly to the presence of foreign organisms.
7.202
Spatio-Temporal Transmission Patterns Of Black Band Disease (Bbd) in A Coral
Community
Assaf ZVULONI* 1,2 , Yael ARTZY-RANDRUP 3 , Lewi STONE 3 , Esti KRAMARSKY-
WINTER 1 , Roy BARKAN 4 , Ariel KUSHMARO 5 , Yossi LOYA 1
1 Department of Zoology, Tel-Aviv University, Tel-Aviv, Israel, 2 The Interuniversity Institute
for Marine Sciences of Eilat, Eilat, Israel, 3 Biomathematics Unit, Department of Zoology, Tel-
Aviv University, Tel-Aviv, Israel, 4 Department of Geophysics and Planetary Sciences, Tel-Aviv
University, Tel-Aviv, Israel, 5 Department of Biotechnology Engineering, Ben-Gurion
University of the Negev, Be’er-Sheva, Israel
Transmission mechanisms of black band disease (BBD) in open marine systems are poorly
understood although this disease is considered as a widespread and destructive coral infectious
disease. The major objective of the study was to assess transmission mechanisms of BBD in an
open marine community from the spatio-temporal patterns of the disease. Susceptible and
infected corals were mapped over an area of 10x10 m in Eilat (Israel, Red Sea) and the
distribution of the disease was examined monthly throughout almost two full disease cycles
(June 2006 – December 2007). We found that the prevalence of the disease is strongly
associated with high water temperature. Infected corals start showing aggregated distributions
(among susceptible corals) on small spatial scales of up to 1.9 m in July, when water
temperatures rise and the disease prevalence increases. Additionally, newly infected corals
clearly develop in proximity to previously infected corals. This provides, what we believe to be
first evidence, that local transmission, often not by direct contact alone, is likely to be an
important factor in the spread of the disease within the studied site. We suggest that loose
infectious material released into the water originating from infected corals may be a significant
mechanism of transmission of the disease. Although potential vectors with limited mobility
(i.e., snails, fireworms) were not observed to be common in the studied site, we can not refute
the possibility that vector mediation mechanism also contributes to disease aggregation.
Another novel finding of this spatio-temporal analysis is that the number of corals that survived
the first disease season and became re-infected during the second season is much higher than
expected by random processes. This points to the possibility that those corals are ‘winter
reservoirs’ of the disease in this reef.
313