Cellular polyamines were acid-extracted
from 36 methanogens, 35 extreme halophiles and 10
thermophiles and analyzed by HPLC and GC. Six
methanogenic archaeal orders were located within the
phylum Euryarchaeota. Spermidine and spermine
were distributed in the genera Methanobacterium and
Methanothermobacter of the order Methanobacteriales.
A high spermine level was found in an alkaliphilic
Methanobacterium species and three thermophilic
Methanothermobacter species. In Methanococcales,
Methanococcus contained spermidine and agmatine
whereas hyperthermophilic Methanocaldococcus
contained spermine and a branched penta-amine,
N4
-bis(aminopropyl)spermidine, in addition to the two
polyamines. Distribution of homospermidine was
limited in Methanoculleus (Methanomicrobiales),
Methanoplanus, Methanocella (Methanocellales),
Methanosaeta, Methanosarcina, Methanolobus,
Methanomethylovorans, Methanosalsum
(Methanosarcinales), but was heterogeneous within the
orders and genera. Low spermidine and spermine
levels in halophilic Methanohalophilus halophilus
(Methanosarcinales) and high spermine and agmatine
levels in alkaliphilic Methanosalsum zhilinae were
observed. In extreme halophiles (Halobacteriales of
Euryarchaeota), agmatine was accumulated in
alkaliphilic species and low polyamine concentration
was detected in acidophilic and neutrophilic species. In
euryarchaeal thermophiles, slightly/moderately
thermophilic acidophiles belonging to
Thermoplasmatales contained spermidine and spermine
whereas extreme thermophiles belonging to
Thermococcales and Archaeglobales ubiquitously
contained N4
-bis(aminopropyl)spermidine (plus
N4
-bis(aminopropyl)norspermidine). Linear
penta-amines, caldopentamine and thermopentamine,
and a linear hexa-amine, caldohexamine, were detected
in some crenarchaeal extreme/hyper-thermophiles
belonging to Desulfurococcales and Thermoproteales but
not in the acidophilic thermophiles belonging to
Sulfolobales and Acidilobales. Branched penta-amines
found in many euryarchaeal extreme/hyper-thermophiles
have never been found in crenarchaeal
extreme/hyper-thermophiles.
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