11th ICRS Abstract book - Nova Southeastern University

8.238
Coral Mucus As A Source Of Bacteria With Antimicrobial Activity
Maya SHNIT-ORLAND* 1 , Ariel KUSHMARO 2
1 Environmental engineering, Ben Gurion University of the Negev, Beer-Sheva, Israel,
2 Biotechnology engineering, Ben Gurion University of the Negev, Beer-Sheva, Israel
In the oligotrophic marine environment there are ecological niches rich in nutrients and
diverse in bacterial populations. One such niche is the coral surface mucus layer.
Interactions amongst microorganisms found in coral mucus may be symbiotic or
competitive; competing over space and food. It has been hypothesized that the microbial
communities found on the coral surface may play a role in the coral defense, possibly
through the production of antimicrobial substances. To find potentially active compounds
produced by coral-mucus bacteria, over 200 selected microorganisms isolated from
mucus layer of a number of scleractinian coral species were grown using agar plating
technique. Screening for antimicrobial substances was performed using overlay and drop
techniques, and antibacterial activity was tested against indicator microorganisms.
Results indicated that approximately 25% of the mucus-associated bacteria demonstrated
bioactivity. Isolates related to the genus Vibrio and Pseudoalteromonas demonstrated
high activity against both gram positive and gram negative bacteria. Isolates related to the
genus Shewanella demonstrated activity against gram positive bacteria. Gram positive
bacteria (Bacillus, Planomicrobium) demonstrated lower activity, primarily against gram
positive bacteria. These results demonstrate the existence of microorganisms with
antimicrobial activity on the coral surface, indicating that they may play a role in
protecting the coral host against pathogens. Further isolation and characterization of these
active substances may lead to novel substances for use in medical and biotechnological
applications.
8.239
Changes in Coral-Surface Bacterial Communities Following Bleaching Induced
Coral Mortality And Their Implications For Ecosystem Function.
Ron JOHNSTONE* 1 , Mark DAVEY 1 , Anna EDLUND 2 , Sara SJÖLING 2
1 Centre for Marine Studies, University of Queensland, St Lucia, Australia, 2 School of
Life Sciences, Södertörn University College, Huddinge, Sweden
The processing and remineralisation of carbon and nutrients by prokaryotes is critical to
the development and sustainability of coral reef ecosystems - underpinning productivity
at all trophic levels. Both the structure and function of coral associated bacterial
communities can alter following a disturbance. This study investigated the differences in
the primary colonization and early succession of bacteria on coral skeletons over time
after coral mortality. Bacterial populations were characterised using denaturing gradient
gel electrophoresis (DGGE) and terminal-restriction fragment length polymorphism (T-
RFLP) analysis of the 16S rRNA gene. This determined there were significant
differences in surface bacterial populations between live and dead coral and a clear
succession of bacteria on dead coral surfaces over a period of 6 months after coral
mortality. Sequencing of DNA fragments from DGGE additionally allowed identification
of specific individuals. By assessing these changes in light of concurrent community
metabolism studies there is clear indication that the changes observed in bacterial
populations from living to dead coral may have significant consequences for
biogeochemical process.
Poster Mini-Symposium 8: Coral Microbial Interactions
8.240
Phenotypic characterization of a coral white pox pathogen, Serratia marcescens
Cory KREDIET* 1 , Kim RITCHIE 2 , Erin LIPP 3 , Max TEPLITSKI 4
1 School of Natural Resources and Environment, University of Florida, Gainesville, FL, 2 Marine
Microbiology, Mote Marine Laboratory, Sarasota, FL, 3 Environmental Health Science,
University of Georgia, Athens, GA, 4 Soil and Water Science, University of Florida, Gainesville,
FL
The surface mucopolysaccharide layer (SML) secreted by corals is a rich environment where
bacteria proliferate, with population levels often being several orders of magnitude higher than
in the surrounding waters. Colonization of coral SML and bacterial growth on coral mucus
most likely requires specific regulatory genes and catabolic enzymes. However, the activities
that are required for SML colonization by bacterial pathogens and commensals are not yet
known. Serratia marcescens is an opportunistic pathogen that causes white pox disease of the
elkhorn coral, Acropora palmata. To characterize mechanisms of SML colonization by the S.
marcescens White Pox pathogen, its ability for carbohydrate catabolism was characterized. A
complement of enzymatic activities induced by growth on coral mucus was identified using
defined chromogenic (p-Nitrophenyl) substrates. N-Acetyl-B-D-Galactosaminadase, a-Dgalactopyranosidase,
a-D-glucopyranosidase, B-D-glucopyranosidase and a-L-fucopyranosidase
were induced after two hours of S. marcescens incubation with coral mucus, while B-Dgalactopyranosidase,
a-L-arabinopyranosidase and B-D-fucopyranosidase were induced after
eighteen hours of incubation. The characterization of glycosidases induced by growth on coral
mucus demonstrates that Serratia marcescens relies on specific catabolic genes for its
colonization of Acroporid SML. Induction of these specific enzymes also provides insight into
the types of bonds found in coral mucus. A Biolog EcoPlate was used to characterize the ability
of several isolates of S. marcescens to catabolize model carbon sources. The ability to utilize
fourteen substrates was common to the isolates of S. marcescens isolated from humans, plant
soft rots, channel water, and a White Pox lesion. The coral pathogenic S. marcescens was able
to utilize no additional substrates while the known pathogenic isolates were capable of
metabolizing 13 additional carbon sources. The repertoire of carbohydrate degrading enzymes
in the coral pathogen is likely to be distinct from that of the human and plant pathogenic
isolates.
8.241
Free living Symbiodinium sp. existence in the rocky reef of the Pacific Coast of
Colombia
Pedro CASTRO* 1 , Juan A. SANCHEZ 2
1 Ciencias Biologicas, Universidad de los Andes, Bogota, Colombia, 2 Laboratorio de Biologia
Molecular Marina, Departamento de Ciencias Biologicas, Universidad de los Andes, Bogota,
Colombia
The major climate changes occurring in the Colombian pacific coast are producing dramatic
transformations in the coral reef ecosystems. The free living dynoflagellate Symbiodinium sp.
is a great biological indicator of the resilience of the reef. The hypothesis of the adaptive
bleaching explains how the coral expels the less convenient symbionts and up-takes, from the
water column, the better adapted ones to the actual conditions of the reef. Some studies have
proven the actual existence of this free-living symbionts in the Indopacific ocean, the
Caribbean sea, the Chinese sea and in the Australian great barrier.
The Gorgona Island is a continental-oceanic land mass located at 56 km of the Colombian
Pacific coast. It possesses a perfect environment for the coral reef development. The coral reefs
in Gorgona have been highly affected by the negative action of commercial fisheries and
natives, plus the climatic phenomena such as the ENSO. These harmful environmental and
human-induced factors almost resulted in the total loss of the coral ecosystem. Today a no-take
Marine Protected Area has been established by the government to help to protect the marine
Island Biodiversity. The main goal of this study was to isolate free-living zooxanthella from the
water column taken from the surroundings of the Gorgona Island. The samples were cultured in
a specific-Symbiodinium F/2 media, and subsequently analyzed using a number of molecular
tools. Here we present ecological and molecular evidence demonstrating the existence of
demersal free-living Symbiodinium populations in Pacific reefs. Different cultures were
identified according to the nuclear internal transcribed spacer (ITS2) and posterior banding
pattern (fingerprinting) with the Denaturing Gradient Gel Electrophoresis, DGGE. It is
suggestive that predictions on coral-zooxanthellae symbiosis aclimatation/adaptation and reef
resilience could significantly improve by including the occurrence of free-living zooxanthellae
and their potential dispersers as part of the reef ecosystem
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