Marine Ecosystems Research Department - jamstec japan agency ...

Japan Marine Science and Technology Center
Frontier Research System for Extremophiles
Fig. 8 Morphological properties of Sulfurihydrogenobium subterraneus
A FISH for S. subterraneus-specific probe B Whole
microbial cells stained with DAPI C Electron micrograph of
S. subterraneus
Persephonella hydrogenophila sp. nov.
A novel thermophilic, hydrogen-oxidizing bacterium,
designed as W T , was isolated from a deep-sea
hydrothermal vent chimney sample collected from the
Suiyo Seamount in the Izu-Bonin Arc, Japan, at a
depth of m. The cells were coccoids (.-. mm
in diameter) and straight rods (.-. mm long) under
static and agitated culture conditions, respectively.
The new isolate was an obligate chemolithoautotroph
growing by respiratory nitrate reduction with H
,
forming N
as a final product. Very low concentration
of O
(opt. .-. %, v/v) was also used as an alternative
electron acceptor while reduced sulfur compounds
did not serve as electron donors. Growth was observed
between and .˚C (opt. ˚C; min doubling
time), pH . and . (opt. pH .), and in the presence
of . and . % NaCl (opt. .%) on anoxic
hydrogen-oxidizing growth with nitrate. The G+C
content of the genomic DNA was . mol%.
Phylogenetic analysis based on S rDNA sequence
indicated that the isolate was a member of the recently
described genus Persephonella in a potential new family
within the order Aquificales. On the basis of the
physiological and molecular properties of the new isolate,
the name Persephonella hydrogeniphila sp. nov.
is proposed. The type strain is strain W T (= JCM
T = DSMZ T ).
Marinithermus hydrothermalis sp. nov.
A novel thermophilic marine bacterium, designated
as strain T T , was isolated from a deep-sea hydrothermal
vent chimney sample collected from the Suiyo
Seamount in the Izu-Bonin Arc, Japan, at a depth
of m. The cells were found to be rod-shaped,
occurring in pairs or filamentous, and stained gramnegative.
Growth was observed between and
.˚C (opt. .˚C; min doubling time) and pH
. and . (opt. pH .). The new isolate absolutely
required NaCl in the range between . and . %
NaCl (opt. %). It was a strictly aerobic heterotroph
capable of growing solely on the complex organic
substrates such as yeast extract, tryptone and
Casamino acid, and utilizing glutamate, proline, serine,
cellobiose, trehalose, sucrose, acetate, and pyruvate
as complementary substrates. The G+C content
of the genomic DNA was . mol%. The S rRNA
gene (rDNA) sequence of the isolate was most similar
to those of members of the genus Thermus but distantly
related to them on the genus level of differentiation
(< %). In addition, the phylogenetic analysis
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