> Von: dieter waloszek <dieter.waloszek at biologie.uni-ulm.de>
> Datum: Sa, 11. Okt 2003 13:05:25 Europe/Berlin
> An: "Geoff Read" <g.read at niwa.co.nz>
> Betreff: Re: Report: loss of hemoglobin H2S-binding function in
> annelids
>> Dear Geoff, I would like to ask you and the Annelida List a question
> based on a notice you distruíbtures on Tuesday, May 2003 (just the
> reprot of a paper):
>>> Bailly, X.; Leroy, R.; Carney, S.; Collin, O.; Zal, F.; Toulmond, A.
>> ; Jollivet, D. 2003: The loss of the hemoglobin H2S-binding function
>> in annelids from
>> sulfide-free habitats reveals molecular adaptation driven by
>> Darwinian positive selection. Proceedings of the National Academy of
>> Sciences 100(10)[May 13, 2003]: 5885-5890. ABSTRACT: The hemoglobin
>> of the deep-sea hydrothermal vent vestimentiferan Riftia pachyptila
>> (annelid) is able to bind toxic hydrogen sulfide (H2S) to free
>> cysteine residues and to transport it to fuel endosymbiotic
>> sulfide-oxidising bacteria. The cysteine residues are conserved key
>> amino acids in annelid globins living in sulfide-rich environments,
>> but are absent in annelid globins from sulfide-free
>> environments.....................
>> Geoff, does this imply that originally annelids tolerated more H2S
> than more modern descendants, or that all taxa lost this capability
> indepedently? And if so, was this also valid for other metazoan taxa?
> Was this a very early invention? Or more primordian mode of
> metabolism? When was it needed first ? Before "Snowball Earth"? During
> this period? After it in the time of formation of large biomasses
> causing the black shales of the late Precambrian through the whole
> Cambrian period? The reason why I ask is the ongoing speculation that
> hydrothermal vents were the areas for animals to survive the period of
> "Snowball Earth". I consider this a rather unlikely story until it can
> be shown that all older branchings had this detoxification method and
> until it can be shown how the most significant larva of all Trochozoa,
> the trochophora could have survived too. Especially planctotrophic
> forms should have been much more affected by SE than any of the
> benthic forms.
>> Thanks for comments, DIETER
Prof. Dr. Dieter Waloszek
Head of the Section for Biosystematic Documentation
University of Ulm, Helmholtzstrasse 20, D-89081 Ulm, Germany
Tel. x49-(0)731-5031000, Fax 5031009
Biosystematic Information Service:
http://biosys-serv.biologie.uni-ulm.de/
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