Orange Montastrea cavernosa recruits?

Jeremy Woodley woodley at uwimona.edu.jm
Fri Aug 4 08:29:56 EDT 2000


Does the fluorescence make more of the energy of uv light available for
photosynthesis?  I am not sufficiently familiar with the action spectra to
judge for myself.

Jeremy Woodley

PO Box 269, McMaster University,        Tel: (905) 627-0393
1280 Main Street West,                  Fax: (905) 627-3966
Hamilton, ON L8S 1C0,                   woodley at uwimona.edu.jm
Canada.                                 or chopwood at hwcn.org

On Fri, 4 Aug 2000, Mikhail Matz wrote:

> ššš Dear Dr. Murray,
> ššš thank you very much for your posting. So, here comes the reasoning
> against photoprotection function of fluorescent pigments from corals.
> These pigments are (in the majority of cases) proteins homologous to
> green fluorescent protein (GFP) from Aequorea victoria, as we recently
> found outš (Matz et al, Nat.Biotechnol. 17: 969-973, 1999).
> ššš We already had a bit of this discussion with prof. Ove
> Hoegh-Guldberg of the University of Queensland (oveh at uq.edu.au), who was
> also suggesting photoprotection as the major role of fluorescent
> proteins. Here is a part of what I wrote to him directly in responce:
> 
> Concerning photoprotection I would rather disagree with you. First of
> all, corals possess a multitude of low-molecular sunscreen
> compounds for this purpose (see, for example, Dunlap, W.C. et al.
> Nature's sunscreen from the Great Barrier Reef, Australia. International
> Journal of Cosmetic Science 20, 41-51 (1998)), so additional recruitment
> of specialized proteins
> for the same purpose seems rather tedious. Still, if it still was
> protection from UV, there is no difference which
> fluorescent color to use - green or red, they are both UV-excitable.
> Meanwhile, our most recent data on molecular features of red-emitters
> suggest that they are advanced versions of greens, so that a point
> mutation would most likely damage
> the red protein making it green. Therefore, red color should have some
> special role in nature (different from green!)
> to be maintained by natural selection, otherwise all the red-emitters
> would have long since deteriorated into greens due to mutation pressure.
> In addition, red-emitters are heavily suboptimal in comparison to greens
> in terms of photoprotection - they all have much lower quantum yields of
> fluorescence.
> 
> ššš So, I think that the coral fluorescence file is still far from being
> closed.
> ššš I would be happy to continue this discussion, especially taking in
> account that the question of the fluorescent proteins function in corals
> is exactly the subject of my current research.
> 
> sincerely yours
> 
> Mikhail Matz, Ph.D.
> Institute of Bioorganic Chemistry
> Miklukho-Maklaya 16/10
> 117871 Moscow, Russia
> š
> 
> Robert Murray wrote:
> 
> > Hi Iain et al,šCoral photobiology is not my area of study, although I
> > did examine the topic some years ago. I believe it is fairly common
> > for many corals to exhibit brightly coloured fluorescence pigments
> > (especially those in shallowest water conditions where light intensity
> > is greatest).šFrom some of the literature I have read I seem to
> > remember a plausible case for these pigments operating as some sort of
> > protection against the destructive energy of short (UV) wavelengths,
> > by liberating some of this energy as harmless (less energetic) visible
> > fluorescence. Perhaps this is one of the discredited theories now. If
> > so, I would be interested to hear the evidence against it.šRegards to
> > allšRobert Murray.šš(What's up Iain?)šš=======================
> > ROBERT MURRAYš BSc, FGA,
> > Discovery Bay Marine Laboratory,
> > Discovery Bay, Jamaica, W.I.
> >
> > Tel. (876) 973 2946
> > Fax. (876) 973 3091
> > rmurray at infochan.com
> > WWW.DBML.ORG
> > =======================š
> >
> >      ----- Original Message -----
> >      From: Mikhail Matz
> >      To: Iain Macdonald ; coral list
> >      Sent: Tuesday, July 25, 2000 11:33
> >      Subject: Re: Orange Montastrea cavernosa recruits?
> >      šHi Iain,
> >      we know a little bit what is the substance causing the
> >      fluorescence in
> >      corals,
> >      and observations, measurements and photos were made about
> >      this
> >      (see http://www.nightsea.com/references.htm for the list of
> >      related
> >      papers and websites)
> >      Moreover, in particular M.cavernosa fluorescence was
> >      measured (in situ)
> >      by Charles Mazel
> >      and is studied by me (in vitro) right now.
> >
> >      However, so far we have absolutely no clue as to the
> >      function of this
> >      fluorescence in
> >      nature (if we forget for a moment about older hypotheses all
> >      of which
> >      seem wrong by now),
> >      and the subject is my primary interest. Your observation is,
> >      as far as I
> >      know, the first
> >      information which might help to link fluorescence to some
> >      aspect of coral
> >      ecology. I would be
> >      extremely grateful if you could provide some more details on
> >      your
> >      observations.
> >      I would like to ask all coral listers as well - perhaps you
> >      saw
> >      something like Iain? Anything
> >      which could give a hint about the function of fluorescence?
> >      Or perhaps I
> >      simply missed something
> >      in literature?
> >      best wishes,
> >
> >      Mike Matz
> >      š
> >
> >      Iain Macdonald wrote:
> >
> >      > During a recent field trip i noted the following along my
> >      transects.
> >      >
> >      > M. cavernosa recruits (i use the plural as this was seen
> >      three
> >      > different times), of only one polyp was noted at approx.
> >      15-20m depth
> >      > to appear to the unaided eye as fluorescent orange. Close
> >      by (ie
> >      > 10cm away) 5 polyps were the typical olive green colour
> >      with this
> >      > "day glow" orange colour around its edges. Again a few cms
> >      away
> >      > larger colonies 20-25 polyps were only olive green. Is
> >      this typical
> >      > for recruits (i think not) or maybe as a result of some
> >      stress
> >      > (sediment) stimulus? I was startled to see such colour
> >      from this type
> >      > of coral and would like to konw of any other observations.
> >
> >      >
> >      > Cheers
> >      >
> >      > Iain Macd.
> >      >
> >      > Room E402 John Dalton Extension Building,
> >      > Department of Environmental and Geographical Science,
> >      > Manchester Metropolitian University,
> >      > Chester Street,
> >      > Manchester,
> >      > M1 5GD
> >      > Tel: 0161 247 6234
> >      > Fax: 0161 247 6318
> >      š
> >
> 



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