[Coral-List] bacteria reservoirs and coral disease

[Shini Sunagawa]

Dear Tom and Andrew,

I read your recent exchange on bacteria reservoirs and coral disease and
thought you may be interested in a study we published a couple of weeks 
ago.
It describes the first-time application of a 16S rRNA microarray to the 
study
of coral diseases, which we believe has high potential to be used as a cost
efficient, high-throughput approach to expedite this field of research.

For more information:
http://newscenter.lbl.gov/feature-stories/2009/02/02/coral-reefs/

We could confirm that A. corallicida was not present in replicate 
samples of
WP diseased M. faveolata colonies, using either of 16S microarray or 
clone library
sequencing data. Besides the proof-of-principle aspect of this study, I 
would like
to highlight the fact that this study was a result of a collaboration 
between E. Weil
in Puerto Rico, the Lawrence Berkeley National Lab, and our lab at UC 
Merced. Similar
efforts will hopefully advance our understanding of bacterial reservoirs 
and their
potential linkage to coral diseases.

The original article can be found here:
http://www.nature.com/ismej/journal/vaop/ncurrent/abs/ismej2008131a.html

Best wishes,
Shini
-------------
PhD candidate
School of Natural Sciences
UC Merced, P.O. Box 2039, Merced, CA 95344
http://sequoia.ucmerced.edu/Shini/index.php



Dear Andrew,

Your observations are very interesting, and I am sure there is
something to them. But to do more you will need to compile 16S rRNA
libraries of the bacterial populations on corals and nearby waters,
rocks, and sediments , and and I know only too well that back home in
Jamaica we don't have the resources to pay for such work! What is
worse is that the funding agencies in the rich countries have
repeatedly dropped the ball on good field work to identify pathogens
and understand how and where these bacteria spread from, so very
little information is available, although Rohwer and Fouke and their
colleagues and others are doing great work on this.

In my view disease results from proliferation of parasites, and has
little to do with coral health per se or pollution in most cases
(Bruce Fouke's group's work on BBD bacteria in Curacao and Serratia
marecescens in White Pox being the exceptions), because if they were
correlated we would see much more disease concentrated in polluted and
stressed areas than we do. In the Turks and Caicos there was no
association of coral diseases with any obvious stress or pollution
factors, but there WERE associations with specific algae. So the key
is to understand where the bacteria come from and how they move.

As mentioned in another post, we found strong statistical evidence
from large scale distribution patterns of association between White
Plague, Black Band, and Gorgonian Disease and various algae in the
Turks and Caicos. That was not based on small scale experiments like
Vu et al., Smith et al., and Nugues et al., which is the obvious next
step to test if there is an association, followed by microbiology. We
did not see such patterns in YBD, but it was too rare there to
tabulate. We did see Pseudo-White Band on palmata and cervicornis, but
I lumped it with WP because they all showed very wide white bands,
5-10 cm across, characteristic of WP, but not the few millimeter-wide
to centimeter bands typical of classic WBD.

Of all the coral diseases, the only one whose pathogens are clearly
known is YBD, thanks to James Cervino's work, and White Pox, thanks to
Katie Patterson. No one has ever convincingly found the pathogen for
WBD to my knowledge, despite some early claims in that direction
(Garriett Smith and Kim Ritchie thought a Vibrio might be involved).
The cyanobacteria in BBD was shown very early on by Antonius and
Rutzler (and later validated by Richardson and colleagues) NOT to be a
pathogen per se, and the coral death resulted from sulfide production
by bacteria at night in the reduced oxygen diffusion matrix created by
cyanobacteria, rather than a pathogenic disease per se. Claims that
Aurantimonas is the cause of WP are now known to be wrong, and it is
likely only to be an occasional secondary opportunist, with the
primary pathogen unknown. Hopefully this situation will change soon,
and perhaps our colleagues can update this brief summary.

Best wishes,
Tom


On Feb 26, 2009, at 3:12 PM, Andrew Ross wrote:


> > Dr. Goreau,
> > After one of the hurricane wave-sets this summer i had several  
> > mature nursery-growing A. cervicornis develop WBD resulting in  
> > partial or total death. Diseased samples were not necessarily  
> > adjacent in the nursery or able to touch.
> > Infection occurred on suspended line nurseries .8 and 1.5M from the  
> > sand on propagated corals that had no physical damage/disease entry  
> > points. No (particular) abrasion, no predation/vectors.
> > The rock 4m away has some sort of endemic WBD as all samples planted  
> > to it die of WBD symptoms. No A. cerv occurs on this rock naturally,  
> > though there is (old) rubble. This rock is a set-point for jack- 
> > season (summertime) fish-pots (not sure if this is important, but  
> > thought i'd mention). The main reef 7m seaward/the other direction  
> > has some living A. cervicornis without disease.
> >
> > The site is the Widowmaker Cave dive site off the MoBay airport. You  
> > may know the spot. I've been growing coral on lines here for 3 years  
> > and have only seen WBD in the nursery on this occasion.
> >
> > The illness/pathogen seems to be in the sand or in the sediments of  
> > that rock. The nursery corals were infected when the storm brought  
> > up/over the pathogen.
> >
> > Thanks for the paper. i've enjoyed all the discussion this week and  
> > the papers mentioned have been very useful.
> >
> > Andrew