sjhoward at nyx10.cs.du.edu (Scott Howard) wrote:
>In article <43l2cv$j5c at agate.berkeley.edu>, xxx at yyy.berkeley.edu wrote:
>>>Two questions - first, are the bacteria that are found along
>>the deep sea vents most closely related to other chemoautotrophic
>>species found elsewhere, or are the deepsea bacteria more closely
>>related to normal strains of bacteria (ie, non-chemoautotrphic
>>ones.)?
>>The bacteria and archae found near the many types of deep sea vents
>are related to a broad range of microorganisms found outside deep sea
>hydrothermal zones, at least if you believe phylogenies inferred from rRNA
>sequences. Whatever "normal" means is completely a matter of
>perspective- I think its remarkable that organisms can function in an
>atmosphere as caustic as oxygen and have their chemical reactions still work
>at temperatures low as 25C.
Many people consider "normal" to be E.coli!!!! As in "if E.coli doesn't
do it, it doesn't happen!"
There's a huge range of bacteria found around the vents. Among the
obligately autotrophic ones oxidizing sulphide, many are closely related
to (or members of) the genus Thiomicrospira (as, it seems, are many of
the symbionts). The more versatile colourless sulphur bacteria seem to be
dominated by members of the genus Beggiatoa - including some of the
largest bacteria known. There are other bacteria, including methane
oxidizers.
>>>>Secondly, the professor said that most of these bacteria use the
>>Calvin cycle. She did mention that there were some bacteria that
>>didn't use the Calvin cycle... what types of bacteria are these?
>>And how do they function?
>>>>There are at least three other ways of fixing carbon outside of the Calvin
>Cycle,
>and the distribution on these methods is widely scattered among microbial
>groups.
>For a nice perspective on this, pick up a copy of "Bacterial Metabolism"
>by Gottschalk.
Good thought! - and for information specifically about the vents, I
suggest you do a search on reviews by Holger Jannasch.
--
Dr. Lesley A. Robertson
Kluyver Laboratory for Biotechnology
Delft University of Technology, the Netherlands
L.A.Robertson at stm.tudelft.nl
