11th ICRS Abstract book - Nova Southeastern University

8.230
Metabolic Profiling Of Microbial Communities Within The Surface
Mucopolysaccharide Layer Of Corals
Kathy KILGORE* 1,2 , Scott GRAVES 1 , Roy YANONG 1 , Craig WATSON 1 , Ilze
BERZINS 3
1 University of Florida, Tropical Aquaculture Laboratory, Ruskin, FL, 2 The Florida
Aquarium, Tampa, 3 The Florida Aquarium, Tampa, FL
As part of a larger project involving coral reef restoration in the Florida Keys using
colonies derived from aquacultured fragments, we attempted to characterize the
metabolic diversity of the surface microbiota of seven species of Atlantic Scleractinia
using Biolog ® EcoPlates. One of the overall goals of the project was to determine if
survival and growth of reintroduced fragments was affected by various culture techniques
(open ocean “control” site, land-based flow-through system, and greenhouse recirculating
system). Further, preliminary data involving the identification of individual bacterial
strains suggested that a shift in the coral surface microbial community occurs during
times of disease. Therefore, we addressed two separate questions with the metabolic
profiling methodology: 1) Do surface microbial communities shift during times of
disease; and 2) will these populations also shift depending upon their culture conditions?
Samples of the surface mucopolysaccharide layer (SML) from two fragments of each
species from the two land-based facilities were obtained after a six-month period in
culture (December 2006). These samples were obtained by direct suction with a syringe
and used to inoculate the EcoPlates. Turbidity and tetrazolium peak data were
collected for each sample every 12-24 hours for a 192-hour period. At that same time,
those fragments that passed a health certification process were then transplanted to the
field site with the “control” fragments. Subsequent SML samples from all three groups
were obtained in May, August, and December 2007.
Microbial community analyses at the 72-hour time point using a Jaccard Index revealed
similarities in the metabolic profiles of the coral SML at the two land-based culture sites
as well as in comparing those to samples from the open ocean site. In contrast,
comparison of healthy to diseased samples revealed differences in the metabolic profiles
obtained.
8.231
Characterizing Uncultured Coral-Associated Bacteria in Genotypically Distinct
Colonies of Acropora palmata Using Universal 16S rDNA Primers
Pascal MEGE* 1 , W. Owen MCMILLAN 2 , María Gloria DOMÍNGUEZ-BELLO 1 ,
Edwin HERNANDEZ DELGADO 1 , Tomas HRBEK 1
1 Department of Biology, University of Puerto Rico - Río Piedras, San Juan, Puerto Rico,
2 Department of Genetics, North Carolina State University, San Juan, NC
Over the last three decades, Caribbean Elkhorn coral Acropora palmata and Staghorn
coral Acropora cervicornis have suffered a considerable loss in numbers, resulting in
their recent listing under the US Endangered Species Act. This reduction has been mainly
attributed to White Band disease outbreaks. Because coral disease etiology is poorly
understood, previous efforts have focused on better understanding the coral associatedbacteria
that may act as a barrier to pathogens.
The aim of this study was to characterize the bacterial communities associated with five
healthy and genetically distinct colonies from the same reef near Mona Island, Puerto
Rico. Genotype identities were confirmed using six microsatellite markers. Utilizing
universal bacterial 16S rDNA primers in PCR, 669 sequences were isolated from the five
colonies (ranging from 94 to 158 sequences per sample). Sequence comparisons to the
closest known bacteria using BLAST analysis confirm the species-specificity of the
bacterial community structure as was previously reported for A. palmata and many other
corals. 54% of our sequences matched the uncultured bacterium AY323179 with 98%
similarity or more, a sequence originally isolated from Elkhorn coral (unpublished). Two
additional observations were particularly remarkable: (1) the main taxa found in this
study coincide with previous observations made for A. palmata (e.g. the majority of the
sequences are Proteobacteria), but the ribotypes identified were mostly unknown; (2)
Although species-specificity of the bacterial community structure was evident, there still
was intra-specific variation between colonies, possibly as a result of their own genotypic
variation.
Future work will explore the extent of within-species variation, and focus on its
implication for coral defense mechanisms and possible contributions to conservation.
Poster Mini-Symposium 8: Coral Microbial Interactions
8.232
Metamorphosis Decision Of acropora Larvae in Response To Mixtures Of Exclusive
Cues From Environments
Masayuki HATTA* 1 , Ayaka HORIKOSHI 1 , Chie SASAKI 1 , Yoshimi FURUTA 1
1 Marine and Coastal Biology Center, Ochanomizu University, Tokyo, Japan
Planula larvae of acroporids require positive cues from environments for the initiation of
metamorphosis and settlement, and some calcareous algae and bacteria have been identified as
metamorphosis inducers on the substrata indeed. We also isolated 3 novel bacteria strains that
induce metamorphosis of acroporids, and they were identified as 2 independent species in the
genus Alteromonas. Planulae may sense particular products by those bacteria and convert the
external cues to internal signals that trigger metamorphosis and settlement. A neuropeptide
GLWamide induces metamorphosis of acroporids as we have reported, so it is a candidate for
internal cues as the “Go” sign. On the other hand, there would be also bacteria inhibiting
settlement of planulae on substrata where various bacteria grow in nature. We screened bacteria
that inhibit metamorphosis induction by GLWamide, and isolated two strains. One strain
transiently inhibited the metamorphosis induction by simultaneous application with GLWa.
The active material(s) appeared to be heat labile and larger than 5kDa. The other strain
revealed a persistent inhibitory activity though it required 6hrs-pretreatments prior to the GLWa
administration. Curious but a heat treatment enhanced the activity and split the active
material(s) to two fractions of over and below 5kDa. The both strains turned out to belong to
the genus Pseudoalteromonas. Another neuropeptide, RFamide, can transiently inhibit
GLWamide-induced metamorphosis, and it is one of candidates for the corresponding internal
signal molecules as the “Stop” sign. There would be a number of different positive and
negative metamorphic cues in each small area of the substrata for larvae of acroporids in natural
environments. There should be ecological strategies for larvae to make decisions on
metamorphosis in response to the complicated situations that exclusive positive and negative
cues are simultaneously displayed.
8.233
The Impact Of Ph On Coral Bacterial Community
Maoz FINE 1 , Ehud BANIN 2 , Dalit MERON* 2
1 faculty of life sciences, Bar Ilan University, Ramat GAN, Israel, 2 faculty of life sciences, Bar
Ilan University, Ramat Gan, Israel
Rising concentrations of atmospheric carbon dioxide is acidifying the world’s oceans. Surface
seawater pH is already 0.1 units lower than pre-industrial values and is predicted to decrease by
up to 0.4 units by the end of the century. This drastic change in pH may result in dramatic
changes in the physiology of corals and other ocean organisms, in particular organisms that
build their skeletons/shells from calcium carbonate. In a recent paper (Fine and Tchernov,
Science 2007) our group reported that a decrease in pH (8.2 to 7.4) led to physiology alterations
in the coral Oculina patagonica and Madracis pharensis, leading to complete dissolution of
their skeleton. Interestingly the corals returned to calcify when returned, after a year, to ambient
pH. This physiological change may lead to shifts in the holobiont members. (zooxanthellae,
bacteria etc.). One such shift may involve coral associated microbial communities which in turn
may affect the coral health. In the present study we examined interactions between the coral
Acropora eurystoma and its microbial community following exposure to different pH
treatments (7.3, 7.6 , 8.2) for 10 weeks. The changes in bacterial community in the coral mucus,
tissue and skeleton were analyzed by DGGE, 16s rRNA clone library followed by sequencing,
molecular and classical microbiology methodologies. Our preliminary results show changes in
bacterial community between the treatments. These changes in bacterial communities and their
impact on the coral will be presented.
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