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Applied and Environmental Microbiology, October 2001, p. 4566-4572, Vol. 67, No. 10
0099-2240/01/$04.00+0 DOI: 10.1128/AEM.67.10.4566-4572.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Growth and Phylogenetic Properties of Novel Bacteria Belonging to
the Epsilon Subdivision of the Proteobacteria Enriched from
Alvinella pompejana and Deep-Sea Hydrothermal
Vents
Barbara J.
Campbell,1
Christian
Jeanthon,2
Joel E.
Kostka,3
George W.
Luther III,1 and
S. Craig
Cary1,*
College of Marine Studies, University of
Delaware, Lewes, Delaware 199581;
UMR6539, Centre National de la Recherche Scientifique and
Université de Bretagne Occidentale, 29280 Plouzané,
France2; and Department of
Oceanography, Florida State University, Tallahassee, Florida
323063
Received 20 March 2001/Accepted 4 July 2001
 |
ABSTRACT |
Recent molecular characterizations of microbial communities
from deep-sea hydrothermal sites indicate the predominance of bacteria
belonging to the epsilon subdivision of Proteobacteria (epsilon Proteobacteria). Here, we report the first
enrichments and characterizations of four epsilon
Proteobacteria that are directly associated with
Alvinella pompejana, a deep sea hydrothermal vent
polychete, or with hydrothermal vent chimney samples. These novel
bacteria were moderately thermophilic sulfur-reducing heterotrophs growing on formate as the energy and carbon source. In addition, two of
them (Am-H and Ex-18.2) could grow on sulfur lithoautrotrophically using hydrogen as the electron donor. Optimal growth temperatures of
the bacteria ranged from 41 to 45°C. Phylogenetic analysis of the
small-subunit ribosomal gene of the two heterotrophic bacteria demonstrated 95% similarity to Sulfurospirillum
arcachonense, an epsilon Proteobacteria isolated from
an oxidized marine surface sediment. The autotrophic bacteria grouped
within a deeply branching clade of the epsilon
Proteobacteria, to date composed only of uncultured
bacteria detected in a sample from a hydrothermal vent along the
mid-Atlantic ridge. A molecular survey of various hydrothermal vent
environments demonstrated the presence of two of these bacteria (Am-N and Am-H) in more than one geographic location and habitat. These results suggest that certain epsilon
Proteobacteria likely fill important niches in the
environmental habitats of deep-sea hydrothermal vents, where they
contribute to overall carbon and sulfur cycling at moderate
thermophilic temperatures.
 |
INTRODUCTION |
Several recent molecular studies
have demonstrated the presence and dominance of bacteria belonging to
the epsilon subdivision of Proteobacteria (epsilon
Proteobacteria) that are both free-living and found in
association with metazoans at deep-sea hydrothermal vents (4, 5,
14, 25, 29, 35; Campbell et al., unpublished data). Epsilon
Proteobacteria have also been detected and/or isolated from
deep subsurface sediments, oil fields, activated sludge, and marine
snow (13, 20, 34, 40, 45). Until now, however, epsilon
Proteobacteria have not been cultured from hydrothermal vent
environments. All epsilon Proteobacteria isolated to date are involved in the sulfur cycle by either reducing elemental sulfur to
sulfide or oxidizing sulfide to sulfur. In many cases, a single
bacterium is able to do both (24, 37). A hallmark of the
epsilon Proteobacteria is their ability to utilize a variety of electron acceptors, including oxygen (under microaerophilic conditions), nitrate, several sulfur species, and, in some cases, arsenate, selenate, manganese, and Fe(III) (12, 18, 27, 28,
42). Because of these capabilities, it is not surprising that
they flourish at hydrothermal vents, where there are high levels of
many sulfur species as well as an abundance of heavy metals (10,
17, 22, 23, 36).
Although inferences can be drawn about the biochemistry of hydrothermal
vent epsilon Proteobacteria, little is actually known about
the chemical and thermal conditions needed for the growth of this
dominant bacterial group. There is one report that suggests that an
epsilon Proteobacteria belonging to the
Arcobacter group is involved in filamentous sulfur
production at hydrothermal vents, although it has not been isolated or
phylogenetically characterized (44). Similar filamentous
production of sulfur occurred in continuous-flow H2S
reactors with an Arcobacter sp. isolated from shallow
coastal marine waters (43).
Our laboratory has been investigating the symbiotic relationship
between Alvinella pompejana, a deep-sea hydrothermal vent polychete, and the morphologically and phylogenetically diverse episymbiont community that is integrated into its dorsal epithelium (4, 5, 7, 14). We have demonstrated through a variety of
molecular techniques that members of a single clade of the epsilon
Proteobacteria dominate the microbial community (4, 5,
14). Several attempts have been made in the past to isolate A. pompejana epibionts under mesophilic, aerobic, and
heterotrophic conditions (16, 31-33). In a recent study,
we confirmed that these attempts did not isolate any epsilon
Proteobacteria and that members of the A. pompejana episymbiont community identified previously by molecular
studies (14) are not present in these extensive culture
collections (Campbell et al., unpublished data).
The goal in this study was to isolate epsilon Proteobacteria
from the dorsal epithelium of A. pompejana by enrichment
culture techniques. Positive enrichments would likely further our
understanding of the biochemical conditions necessary for both epibiont
and free-living bacterial growth. In addition, we extended our epsilon Proteobacteria isolation attempts to sulfidic chimney
samples from hydrothermal vents at 13°N latitude along the East
Pacific Rise (EPR) and at the Guaymas basin. A molecular survey of
various hydrothermal vent sites was also performed to investigate the ecology of two novel epsilon Proteobacteria that were
enriched from the 13°N A. pomejana epibiont community.
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MATERIALS AND METHODS |
Sampling and enrichment conditions.
Initial enrichments were
from A. pompejana worms sampled from various hydrothermal
vents along the EPR during the Amistad cruise, May to June 1999, to
13°N (12°49'N, 103°56'W) at a depth of approximately 2,500 m
(Table 1). A. pompejana
specimens (in their associated tubes) were collected and transported to
the surface via the deep-submergence vehicle (DSV) Nautile in an
enclosed container. Once on board, A. pompejana worms were
removed from their tubes and associated chimneys, and washed three
times in sterile 0.22-µm-filtered seawater, and the epibiont
community (found mainly on the hair-like projections) were scraped into a sterile 50-ml tube. The hairs were slightly homogenized with a
20-gauges needle in a final volume of 10 ml containing sterile seawater
and aseptically transferred to anaerobic medium (described below). A
portion of the homogenate was saved for DNA extraction and preservation
in glycerol at
80°C.
For the enrichments from chimney samples, sulfides were collected from
the Guaymas basin, a sediment- and hydrocarbon-rich
hydrothermal site
in the Gulf of California (27°00'N, 111°24'W)
at a depth of
approximately 2,000 m, during the Extreme 2000 cruise,
January 2000 (Table
1). The outsides of chimneys were scraped
aseptically into
sterile tubes, and anaerobic sterile seawater
was added (10×,
vol/vol).
Approximately 1 ml of diluted sample (hairs or chimney) was used for
each
enrichment.
Medium used for enrichments was modified from that of Widdel and Bak
(
47) and contained (per liter): 20 g of NaCl, 3 g of
MgCl
2 · 6H
2O, 0.15 g of
CaCl
2 · 2H
2O, 0.5 g of KCl,
0.25 g of
NH
4Cl, 0.2 g of
KH
2PO
4, 1 ml of trace element solution
(
46),
1 ml of selenite-tungstate solution, 0.015 g of
resazurin, 30
ml of 1 M NaHCO
3, 1 ml of vitamin
mixture solution, 1 ml of vitamin
B
12 solution, 1 ml
of thiamine solution, and 5 ml of 0.2 M Na
2S
as a reductant
(
47). Elemental sulfur (approximately 5 g/liter)
was
sterilized by heating to 100°C three times and added aseptically
after the medium was autoclaved. The final pH was adjusted to
approximately 7.0, and the headspace consisted of
N
2-CO
2 (80:20;
150
kPa).
A combination of three potential electron donors and carbon sources
(formate [20 mM final concentration], acetate [2 mM final
concentration], and pyruvate [20 mM final concentration]) was
added
separately from sterile, anoxic stocks to individual tubes
before
inoculation for the 13°N enrichments. Enrichments from
the chimneys
collected at Guaymas basin were performed in the
sulfur medium with
added formate and acetate. The
A. pompejana enrichments were
incubated at 30, 50, and 65°C, while the chimney
enrichments were
incubated at 45 and 60°C. Growth was monitored
microscopically.
Positive enrichments were subcultured five times on board ship and/or
in the laboratory until stable cultures (cultures that
did not change,
based on microscopic or molecular analysis) were
obtained. These
subcultures were considered pure when microscopic
and molecular
evidence indicated only one type of bacterium per
culture. DNA
was extracted from all the positive enrichments and
stable cultures and
subjected to DNA fingerprinting analysis (denaturing
gradient gel
electrophoresis [DGGE]) as described previously (
4,
38).
Universal primers for both bacteria and archaea were used
in the DGGE
analysis to assess the purity of the cultures. In
addition purity of
the cultures was assessed by microscopic
analysis.
Growth characterizations.
Two of the epsilon
Proteobacteria cultures that were considered pure (Am-H and
Am-N) were subjected to limited physiological assessment. Initial
cultures were grown in the sulfur medium described above with the
addition of formate and acetate as potential electron donor and carbon
source, respectively.
The temperature range tested was from 30 to 65°C. Other carbon
sources (CO
2, pyruvate [20 mM], fumarate [0.2%], 0.2%
peptone,
formate [10 mM], and acetate [10 mM]), electron donors
(H
2 and
formate), and electron acceptors [sulfite (5 mM), thiosulfate
(10 mM), and Fe(III)] were evaluated. In
addition, growth with
various gas mixtures
(H
2-CO
2, 90:10, 150 kPa, and N
2,
100%, 150
kPa) was tested. Growth using Fe(III)-oxyhydroxide was
evaluated
on media prepared and manipulated as above (
47).
We modified the medium for Fe reducers by adding 2 mM ferrous chloride
as a reductant in place of dissolved sulfide. Amorphous
Fe(III)-oxyhydroxide was added to the autoclaved medium as the
sole
electron acceptor to a final concentration of 50 mM. The
Fe(III) oxide
was prepared by neutralizing a solution of FeCl
3,
rinsing,
and autoclaving as described previously (
21). All medium
preparation and manipulations were carried out under strictly
anoxic
conditions unless otherwise specified. Sterile medium components
for
the Fe(III) medium were combined, and the medium was dispensed
into
serum bottles which were sealed with butyl rubber stoppers
under a gas
stream of 90% N
2 and 10% CO
2 (100 kPa).
Inocula for
all the metabolic characterizations were 1/20th volume.
Positive
cultures were subcultured an additional time to confirm growth
in the tested medium (and not growth from the original inoculum).
Negative cultures were tested from the source inoculum at least
twice.
Additional negative controls included growth with no added
substrates
(other than the basal minimal medium with and without
added sulfur).
Cells were counted after 3 days by epifluorescent
microscopy after
fixation with 3.7% formaldehyde, staining with
DAPI
(4',6'-diamidino-2-phenylindole) (2 µg/ml), and filtration
onto a
0.22-µm polycarbonate filter (
30). Growth was scored
as
positive if there was a greater than fivefold increase in cells
compared to control tubes with no added
substrates.
Growth curves of the stable subcultures were performed four times at
their optimal temperatures in minimal enrichment medium
with added
sulfur and formate (20 mM) under an N
2-CO
2 gas
headspace.
Growth was also measured in sulfur medium without formate.
Cells
were counted by epifluorescent microscopy as described
above.
Hydrogen sulfide production was measured using the Cline method
(
6). Light photomicrographs were obtained after staining
with DAPI (2 µg/ml) as described above. The lengths and widths
of the
bacteria were measured on an Olympus Provis AX70 microscope
using a
100× objective with a Chroma 31000 band pass filter set.
Lengths and
widths of the bacteria were estimated from a frequency
plot of the
values for approximately 100 individual
bacteria.
Phylogenetic assessment.
The 16S ribosomal DNAs (rDNAs) of
the bacteria were amplified from extracted DNA using the 21F and 1518R
primers as described previously (14) and cloned into a
Topo-TA vector (Invitrogen, Carlsbad, Calif.) according to the
manufacturer's instructions. The resulting 16S rDNA clones were
bidirectionally sequenced on an ABI 310 sequencer (Applied Biosystems,
Inc. [ABI], Foster City, Calif.) using the TA vector-specific primers
M13F and M13R (Invitrogen) as well as 519F, 519R, 1100F, and
1100R (1). DNA sequences were assembled using the
ABI Autoassembler program (ABI) and aligned to other 16S rDNA sequences
using Genetic Data Environment (GDE) (39) as described
previously (14). DNA distance similarities were determined
by the method of Olsen (26). Neighbor-joining and
parsimony trees were obtained in GDE as previously described (14).
Presence of bacteria in the environment.
DNA was extracted
from the A. pompejana epibiont samples listed in Table 1
using an Isoquick DNA extraction kit (ORCA Research, Bothwell, Wash.)
as described previously (4). Several DNA extraction protocols were used on various chimney-flange samples (Table 1) to
evaluate extraction efficiencies and potential PCR inhibition effects.
DNA was initially extracted from approximately 500 µl of ground
chimney samples (slurries) from 9°N and 13°N with
acetyltrimethylammonium
bromide-polyvinylpyrrolidone-

-mercaptoethanol
(CTAB/PVP/

-ME)
method as described previously (
8)
and resuspended in 50 µl
of sterile H
2O. We found better
yields and less inhibition when
extracting from an equal amount of
chimney slurry with the QIAamp
DNA stool mini kit (Qiagen, Valencia,
Calif.). DNA was extracted
from the Guaymas chimney-flange samples
using this kit and resuspended
in 50 µl of sterile H
2O.
From 1 to 10 ng of DNA was used in PCR
for DGGE analysis as described
previously (
4,
38). The universal
forward primer 338F
(with a GC clamp) was also used in combination
with two strain-specific
16S rDNA primers (for Am-H, H607R [5'-
CTCCCGAACTCTAGTCTGA],
and for Am-N, N601R [5'- CTAGATAAACAGTTTCAAGA],
based on
Escherichia coli numbering [3]) in PCR
amplifications
for DGGE to determine the presence of strain Am-H or
Am-N in the
indicated
samples.
Nucleotide sequence accession numbers.
The 16S rDNA
sequences for Am-H, Am-N, Ex-18.1, and Ex-18.2 were deposited in
GenBank and assigned accession numbers AF357197, AF357198, AF357199,
and AF357196, respectively.
 |
RESULTS |
Enrichments.
Enrichments from A. pompejana samples
collected from 13°N that were grown at 30°C yielded bacteria that
varied widely in their morphologies, while little to no growth occurred
at 65°C. Successful enrichments of two morphologically different
populations of bacteria that were grown at 50°C were obtained from
A. pompejana samples collected from two separate
hydrothermal vent sites (Table 1). Initially, both enrichments
contained a dominant bacterial morphotype, with several minor
morphotypes. After subculturing, only the dominant bacterium in each
enrichment was detected by DGGE and microscopy. The first bacterial
morphotype recovered from three separate A. pompejana
specimens (A, N, and X) grew on acetate-formate-sulfur medium (Table
1). These cultures consisted of slow-growing (doubling time, >24 h at
50°C) motile vibrioid cells (Table 2).
Stable subcultures of the dominant morphotypes were obtained after
decreasing the incubation temperature to 45°C. DGGE analysis of the
three subcultures demonstrated three identically migrating bands that were indistinguishable by sequence analysis of 110 bp (data not shown).
These strains were considered similar. Therefore, a subculture from the
N enrichment was chosen to be characterized; it was designated Am-N.
The second bacterial morphotype (Am-H) was enriched from a single
A. pompejana specimen collected from PP55, also located
along the EPR at 13°N (Table
1). After several subcultures in
the
same medium as above, it was also confirmed to be a single
bacterium by
both microscopy and DGGE analysis (data not shown).
Compared to the
first bacterium, it grew faster at 50°C, was smaller
in
size, and was also motile (Table
2).
Two other epsilon
Proteobacteria, designated Ex-18.1 and
Ex-18.2, were enriched from several chimney samples collected from
hydrothermal vents in the Guaymas basin using similar conditions
as
above, except the initial incubation temperature was reduced
to 45°C
and the sulfur medium contained only formate and acetate.
The first
bacterium, Ex-18.1, was morphologically and phylogenetically
similar to
Am-N. Morphologic and DGGE analysis of enrichments
from K2 and Robin's
Roost indicated that bacteria identical to
Ex-18.1 were also found at
these vent sites (Table
1 and data
not shown). The types of samples
used in the enrichments were
somewhat different; the sample from K2 was
a flange outcropping,
while the sample from Robin's Roost was a
sulfidic chimney. The
second chimney bacterium, Ex-18.2, was enriched
from three other
samples collected from Guaymas: Robin's Roost flange,
another
K2 flange, and a flange collected from Kristin's Summit (Table
1 and data not shown). According to morphologic and DGGE analysis,
it
was morphologically and phylogenetically similar to Am-H.
Preliminary characterization of bacteria and growth rates.
Two
of the isolates, Am-H and Am-N, were chosen for further
characterization. Am-H and Am-N are slightly curved rods with widths of
0.3 and 0.3 µm and lengths of 0.4 and 0.8 µm, respectively (Table
2). Am-H is highly motile, while Am-N is less motile. As shown in Table
2, the temperature growth ranges of these organisms varied slightly;
Am-H generally grew at higher temperatures (up to 55°C but not above)
and had a higher temperature optimum (45°C) than Am-N (50 and 41°C,
respectively). Growth curves for the two bacteria were performed at
least four separate times in a basal minimal medium with added
elemental sulfur and formate. Representative curves are illustrated in
Fig. 1. Am-N had a slightly longer
doubling time than Am-H (9 h versus 6 h, respectively), as
calculated by the slope of the growth curves during the linear phase of
growth (Fig. 1). Based on the graphic comparison of the number of cells per mole of H2S produced, growth yields of Am-H were
approximately twice that of Am-N (data not shown).

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FIG. 1.
Representative growth curves of strains Am-H (A, )
and Am-N (B, ). Cell densities (solid lines) and hydrogen sulfide
production (dashed lines) were measured with formate as the electron
donor and elemental sulfur as the electron acceptor at their individual
temperature optimums under anaerobic conditions
(N2-CO2 gas phase). Controls were inoculated
tubes without added formate ( ).
|
|
Growth of Am-N and Am-H was tested with a limited series of gas
mixtures, electron acceptors, and carbon sources (Table
2).
Both Am-N
and Am-H grew heterotrophically using formate as a carbon
source and
sulfur as the electron acceptor. They were not able
to use thiosulfate,
sulfite, and Fe(III)-oxyhydroxide as alternative
electron acceptors in
the presence of formate. None used acetate
as an energy and carbon
source. With sulfur, Am-H was able to
grow lithoautotrophcally using
hydrogen and formate as electron
donors and heterotrophically in the
presence of pyruvate. Fermentation
of fumarate was performed by Am-N.
The ability of Am-N and Am-H
to grow under low levels of oxygen and
with nitrate as electron
acceptors was not
tested.
Phylogenetic affiliations.
According to their 16S rDNA
sequences, Am-N and Am-H and their close relatives from the Guaymas
basin (Ex-18.1 and Ex-18.2) grouped into the epsilon subdivision of the
Proteobacteria (Fig. 2). Am-N
showed 99.2% identity with Ex-18.1 and 96.5 and 94.5% identity with
Sulfurospirillum arcachonense and Sulfurospirillum barnesii, respectively, by DNA distance analysis. Am-H and Ex-18.2 (Fig. 2) were much more distantly related to the
Sulfurospirillum, grouping into a previously described
deeply branching epsilon clade that contains uncultured 16S rDNA clones
from a hydrothermal vent cap deployed at the Snake Pit vent along the
mid-Atlantic ridge (35). Am-H was 99% identical to
Ex-18.2 and showed 95.4 and 87.5% identity to VC2.1 Bac43 and VC2.1
Bac30, respectively.

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FIG. 2.
Phylogenetic tree showing the relationships between
isolated strains with other members of the epsilon subdivision of the
Proteobacteria. The trees are based on alignments of
approximately 1,500 bp from the 16S rDNA gene minus insertions,
deletions, and ambiguous bases. E. coli was used as the
outgroup. Bootstrap values from 100 resamplings are indicated prior to
the branch points of the tree. Sequences from the isolates are marked
in boldface type. The scale bar represents the calculated number of
changes per nucleotide position.
|
|
Ecological significance of isolates.
Nine A. pompejana samples and nine chimney or flange samples (samples
designated by letters and numbers in Table 1) were tested by PCR with
strain-specific primers, followed by DGGE analysis for the presence of
bacteria with migration patterns identical to those of either Am-N or
Am-H (Fig. 3). Positive PCRs which migrated identically to Am-N on a DGGE gel were obtained from all
A. pompejana specimens tested from the 13°N latitude with the primer designed to specifically amplify Am-N (representative amplifications are shown in Fig. 3A). Bands migrating identically to
Am-N were also amplified from DNA extracted from two chimney samples,
one from 13°N (M chim.) and one from 9°N (97 chim.). No positive
PCRs were obtained with the Am-N-specific primer with DNA extracted
from one chimney sample from 9°N (215 chim.) or from any of the
samples collected from the Guaymas basin. Similar results were obtained
with an Am-H-specific primer. However, two A. pompejana
specimens were negative (Am-G and Am-N), while all the chimney samples
from 9°N and 13°N were positive (Fig. 3B). Very weak amplification
products were obtained with an Am-H-specific primer on two samples
collected from the Guaymas basin, and three others were negative.

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FIG. 3.
DGGE of positive PCR products obtained after
amplification using strain-specific primers for Am-N (A) and Am-H (B).
Lanes 1 to 8, separated amplification products obtained from samples of
various A. pompejana epibiont biomass and hydrothermal
chimney samples as listed in Table 1. Lane 9, positive controls (Am-N
in A, Am-H in B). A slight frown occurred in the gel shown in panel
B.
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|
The
A. pompejana worms and the three chimney samples from
9°N and 13°N were also tested for the presence of the isolates Am-H
and Am-N by DGGE analysis with universal primers to detect all
bacteria
present in the samples (Fig.
4). The
A. pompejana bacterial
communities from 13°N contained
very similar members, as indicated
by the number of identically
migrating bands. However, no bands
corresponding to Am-H or Am-N were
observed on the gel, suggesting
that these bacteria were minor members
of the communities tested.
This was also the case for two of the
chimney samples (M and 97).
Chimney 215 did have observable bands
migrating similarly to PCR
amplicons from the bacterial cultures Am-H
and Am-N (indicated
by the arrows in Fig.
4). After sequencing these
highly visible
bands, it was determined that they were not identical to
either
Am-H or Am-N, confirming the previous negative PCR results with
the Am-N-specific primers on the sample from chimney 215.

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FIG. 4.
DGGE of positive PCR products obtained after
amplification using universal primers. Lanes 1 to 11, separated
amplification products obtained from samples of various A. pompejana epibiont biomass and hydrothermal chimney samples as
listed in Table 1. Lanes 12 and 13, positive controls. Arrows indicate
bands that were reamplified for DNA sequencing.
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 |
DISCUSSION |
This is the first report of the isolation of
Proteobacteria belonging to the epsilon subdivision from
deep-sea hydrothermal vents. Our and previous PCR-based experiments
demonstrated that in hydrothermal vent environments, epsilon
Proteobacteria dominate the free-living organisms on the
outer surfaces of chimneys and/or are closely associated with
invertebrate hosts (4, 5, 14, 25, 29). Large percentages
of diverse epsilon Proteobacteria have also been detected
from a vent cap deployment along the mid-Atlantic ridge
(35). These reports suggest that the epsilon subdivision of Proteobacteria plays a major role in the bacterial
communities at hydrothermal vents. One of the strains described here
(Am-H) has some properties similar to other cultured epsilon
Proteobacteria, such as growth with fumarate. However, both
strains are novel in that they grow at moderate thermophilic
temperatures. While we have no direct evidence for carbon fixation by
Am-H, the deeply branching epsilon Proteobacteria are able
to autotrophically use elemental sulfur, hydrogen, and CO2
for growth under anaerobic conditions.
Autotrophy involving the reduction of elemental sulfur is not unique to
the Proteobacteria, but has only been described in one
other previously identified epsilon Proteobacteria (an
Arcobacter sp.) isolated from oil field brine
(13). Until this report, all anaerobic elemental
sulfur-reducing chemolithoautotrophic bacteria described from
hydrothermal vents were thermophiles and hyperthermophiles (2,
19, 41). Many sulfur-oxidizing chemolithoautotrophs have been described from marine environments, including hydrothermal vents, but these microorganisms oxidize sulfides in the presence of
O2 (9, 15). Alternate chemolithoautotrophic
metabolisms involving the disproportionation of elemental sulfur have
been described in marine environments (11), but have not
been described from bacteria isolated at deep-sea hydrothermal vents or
by epsilon Proteobacteria. It seems likely that the deeply
branching epsilon Proteobacteria described here (Am-H), and
possibly other phylogenetically similar bacteria (35),
fill an important niche in the environmental habitat of deep-sea
hydrothermal vents, where they may contribute both to an increase in
biomass and to overall carbon production.
Two of the epsilons (Am-N and Ex-18.1) described in this report
phylogenetically group with the Sulfurospirillum spp., a
distinct clade within the epsilon subdivision of
Proteobacteria (12, 37, 42). Other members of
the Sulfurospirillum group are not able to grow at 42°C
but have pH requirements similar to that of Am-N.
Sulfurospirillum spp. also use a variety of electron donors and are able to ferment fumarate (42). S. arcachonense, the closest phylogenetic representative to
Am-N, also seems very close metabolically since, like Am-N, it
does not reduce thiosulfate, sulfite, and Fe(III). However, another
species of this genus, S. barnesii, is able to use a diverse
spectrum of electron acceptors, including arsenate, selenate, and
Fe(III) (18, 27, 42), indicating the potential of diverse
physiological abilities of these bacteria, an adaptation certainly
appropriate for organisms thriving in deep-sea hydrothermal vent environments.
The epsilon Proteobacteria described in this paper
were enriched from both A. pompejana samples and
geographically distinct chimney samples from deep-sea hydrothermal
vents from 13°N and the Guaymas basin. Because of the presumed and
measured chemical differences in the samples from the sediment-starved
EPR and the hydrocarbon and sediment-rich Guaymas basin (10, 22,
23; Luther et al., unpublished data), we were initially
surprised by our ability to enrich for such phylogenetically similar
bacteria (99%) from these two areas. We therefore believe that the
physiological abilities of the cultured epsilon
Proteobacteria reported in this paper are possibly far more
diverse than we have described. The molecular survey that demonstrated
these isolates at geographically and chemically distinct
hydrothermal vent sites (9°N, 13°N, and the Guaymas basin) supports
the hypothesis that these epsilon Proteobacteria
potentially have wide physiological abilities.
While we were able to cultivate hydrothermal vent epsilon
Proteobacteria from the A. pompejana episymbiont
community as well as from chimney samples, we were unsuccessful in
enriching for the dominant filamentous epsilon
Proteobacteria phylotypes found integrated into the
hair-like projections on the worm's dorsal epithelium (5,
14). We found, during the course of this investigation, that the
medium designed for cultivation of epsilons was limited and
selected for specific growth of two types of epsilon
Proteobacteria. The culturing conditions were restricted by
temperature range, carbon source used, electron donor-acceptor
pairs tested, and pH. Any one or a combination of these factors will
need to be tested further for potential growth of the free-living
counterparts of the dominant episymbionts that were detected in chimney
samples during our previous investigation (5).
Furthermore, as determined by their relative band intensities by DGGE
analysis, neither Am-N nor Am-H was numerically dominant in any of the
13°N A. pompejana samples or chimney samples from 9°N.
However, a bacterium phylogenetically identical to Am-H was detected by
DGGE analysis in a 10
7 dilution of a hydrothermal vent
chimney enrichment for Fe(III) reducers from the same cruise at 13°N
(38). Additionally, phylogenetically similar deeply
branching bacteria have been observed at other hydrothermal vent sites
devoid of A. pompejana specimens (35). It seems
likely, then, that Am-H (or phylogenetically similar bacteria) exists
in higher numbers in the chimney samples than on A. pompejana specimens from 13°N EPR.
Bacteria belonging to the epsilon subdivision of the
Proteobacteria are clearly important in the ecology of
hydrothermal vents, as indicated by their dominance in several
molecular surveys (4, 14, 25, 35). The enrichment of
autotrophic and heterotrophic epsilon Proteobacteria
contributes to our understanding of carbon and sulfur cycling in
hydrothermal vent environments. Our successful culturing of four
phylogenetically distinct epsilon Proteobacteria from
different hydrothermal vent environments paves the way for more
biochemical testing of these isolates and further attempts to culture
additional epsilons from these extreme environments.
 |
ACKNOWLEDGMENTS |
This research was supported by grants to S.C.C. from the LEXEN
initiative (OCE-9907666) and the Delaware Sea Grant Program (R/B37) as
well as a LEXEN initiative grant to G. Luther and S.C.C. (OCE-9729784).
The Amistad cruise was organized by the Centre National de la Recherche Scientifique.
We gratefully acknowledge the following people for their technical
assistance: L. Waidner, S. L'Haridon, D. Dalton, and M. Cottrell. We
thank K. Coyne, C. DiMeo, and two anonymous reviewers for critically
reviewing the manuscript. We thank the captains and crews of the
R/Vs Atlantis and L'Atalante and
especially the pilots of the DSVs Alvin and
Nautile for their essential roles in the collection of specimens.
 |
FOOTNOTES |
*
Corresponding author. Mailing address: College of
Marine Studies, University of Delaware, Lewes, DE 19958. Phone: (302)
645-4078. Fax: (302) 645-4007, E-mail: caryc{at}udel.edu.
 |
REFERENCES |
| 1.
|
Amann, R. I.,
W. Ludwig, and K. H. Schleifer.
1995.
Phylogenetic identification and in situ detection of individual microbial cells without cultivation.
Microbiol. Rev.
59:143-169[Abstract/Free Full Text].
|
| 2.
|
Blochl, E.,
R. Rachel,
S. Burggraf,
D. Hafenbradl,
H. W. Jannasch, and K. O. Stetter.
1997.
Pyrolobus fumarii, gen. and sp. nov., represents a novel group of archaea, extending the upper temperature limit for life to 113 degrees C.
Extremophiles
1:14-21[CrossRef][Medline].
|
| 3.
|
Brosius, J.,
T. J. Dull,
D. D. Sleeter, and H. Noller.
1981.
Gene organization and primary structure of a ribosomal RNA operon from Escherichia coli.
J. Mol. Biol.
148:107-127[CrossRef][Medline].
|
| 4.
|
Campbell, B. J., and S. C. Cary.
2001.
Characterization of a novel spirochete associated with the hydrothermal vent polychaete annelid Alvinella pompejana.
Appl. Environ. Microbiol.
67:110-117[Abstract/Free Full Text].
|
| 5.
|
Cary, S. C.,
M. T. Cottrell,
J. L. Stein,
F. Camacho, and D. Desbruyères.
1997.
Molecular identification and localization of a filamentous symbiotic bacteria associated with the hydrothermal vent annelid Alvinella pompejana.
Appl. Environ. Microbiol.
63:1124-1130[Abstract].
|
| 6.
|
Cline, J. D.
1969.
Spectrophotometric determination of hydrogen sulfide in naturals waters.
Limnol. Oceanogr.
14:454-458.
|
| 7.
|
Cottrell, M. T., and S. C. Cary.
1999.
Diversity of dissimilatory bisulfite reductase genes of bacteria associated with the deep-sea hydrothermal vent polychaete annelid Alvinella pompejana.
Appl. Environ. Microbiol.
65:1127-1132[Abstract/Free Full Text].
|
| 8.
|
Dempster, E. L.,
K. V. Pryor,
D. Francis,
J. E. Young, and H. J. Rogers.
1999.
Rapid DNA extraction from ferns for PCR-based analyses.
Biotechniques
27:66-68[Medline].
|
| 9.
|
Durand, P.,
A. L. Reysenbach,
D. Prieur, and N. Pace.
1993.
Isolation and characterization of Thiobacillus hydrothermalis sp. nov., a mesophilic obligately chemolithotrophic bacterium isolated from a deep-sea hydrothermal vent in Fiji Basin.
Arch. Microbiol.
159:39-44[CrossRef].
|
| 10.
|
Edmond, J. M., and K. L. Von Damm.
1985.
Chemisty of ridge crest hot springs.
Biol. Soc. Wash. Bull.
6:43-47.
|
| 11.
|
Finster, K.,
W. Liesack, and B. Thamdrup.
1998.
Elemental sulfur and thiosulfate disproportionation by Desulfocapsa sulfoexigens sp. nov., a new anaerobic bacterium isolated from marine surface sediment.
Appl. Environ. Microbiol.
64:119-125[Abstract/Free Full Text].
|
| 12.
|
Finster, K.,
W. Liesack, and B. J. Tindall.
1997.
Sulfurospirillum arcachonense sp. nov., a new-microaerophilic sulfur-reducing bacterium.
Int. J. Syst. Bacteriol.
47:1212-1217[Abstract/Free Full Text].
|
| 13.
|
Gevertz, D.,
A. J. Telang,
G. Voordouw, and G. E. Jenneman.
2000.
Isolation and characterization of strains CVO and FWKOB, two novel nitrate-reducing, sulfide-oxidizing bacteria isolated from oil field brine.
Appl. Environ. Microbiol.
66:2491-2501[Abstract/Free Full Text].
|
| 14.
|
Haddad, M. A.,
F. Camacho,
P. Durand, and S. C. Cary.
1995.
Phylogenetic characterization of the epibiotic bacteria associated with the hydrothermal vent polychaete Alvinella pompejana.
Appl. Environ. Microbiol.
61:1679-1687[Abstract].
|
| 15.
|
Jannasch, H. W.,
C. O. Wirsen,
D. C. Nelson, and L. A. Robertson.
1985.
Thiomicrospira crunogena sp. nov., a colorless, sulfur-oxidizing bacterium from a deep-sea hydrothermal vent.
Int. J. Syst. Bacteriol.
35:422-424[Abstract/Free Full Text].
|
| 16.
|
Jeanthon, C., and D. Prieur.
1990.
Susceptibility to heavy metals and characterization of heterotrophic bacteria isolated from two hydrothermal vent polychaetes, Alvinella pompejana and Alvinella caudata.
Appl. Environ. Microbiol.
56:3308-3314[Abstract/Free Full Text].
|
| 17.
|
Juniper, S. K., and J. Sarrizan.
1995.
Interaction of vent biota and hydrothermal deposits: present evidence and future experimentation, p. 178-193.
In
S. E. Humpris, R. A. Zierenberg, L. S. Mullineaux, and R. E. Thomson (ed.), Seafloor hydrothermal systems: physical, chemical, biological, and geological interactions. American Geophysical Union, Washington, D.C.
|
| 18.
|
Laverman, A. M.,
J. S. Blum,
J. K. Schaefer,
E. J. P. Phillips,
D. R. Lovley, and R. S. Oremland.
1995.
Growth of strain SES-3 with arsenate and other diverse electron acceptors.
Appl. Environ. Microbiol.
61:3556-3561[Abstract].
|
| 19.
|
L'Haridon, S.,
V. Cilia,
P. Messner,
G. Raguenes,
A. Gambacorta,
U. B. Sleytr,
D. Prieur, and C. Jeanthon.
1998.
Desulfurobacterium thermolithotrophum gen. nov., sp. nov., a novel autotrophic, sulpfur-reducing bacterium isolated from a deep-sea hydrothermal vent.
Int. J. Syst. Bacteriol.
48:701-711[Abstract/Free Full Text].
|
| 20.
|
Li, L. N.,
C. Kato, and K. Horikoshi.
1999.
Bacterial diversity in deep-sea sediments from different depths.
Biodivers. Conserv.
8:659-677[CrossRef].
|
| 21.
|
Lovley, D. R., and E. J. P. Phillips.
1986.
Organic-matter mineralization with reduction of ferric iron in anaerobic sediments.
Appl. Environ. Microbiol.
51:683-689[Abstract/Free Full Text].
|
| 22.
|
Luther, G. W.,
B. T. Glazer,
L. Hohmann,
J. I. Popp,
M. Taillefert,
T. F. Rozan,
P. J. Brendel,
S. M. Theberge, and D. B. Nuzzio.
2001.
Sulfur speciation monitored in situ with solid state gold amalgam voltammetric microelectrodes: polysulfides as a special case in sediments, microbial mats and hydrothermal vent waters.
J. Environ. Manage.
62:61-66[CrossRef].
|
| 23.
|
Luther, G. W.,
T. F. Rozan,
M. Taillefert,
D. B. Nuzzio,
C. Di Meo,
T. M. Shank,
R. A. Lutz, and S. C. Cary.
2001.
Chemical speciation drives hydrothermal vent ecology.
Nature
410:813-816[CrossRef][Medline].
|
| 24.
|
Macy, J. M.,
I. Schroder,
R. K. Thauer, and A. Kroger.
1986.
Growth the Wolinella succinogenes on H2S plus fumarate and on formate plus sulfur as energy-sources.
Arch. Microbiol.
144:147-150[CrossRef].
|
| 25.
|
Moyer, C. L.,
F. C. Dobbs, and D. M. Karl.
1995.
Phylogenetic diversity of the bacterial community from a microbial mat at an active, hydrothermal vent system, Loihi Seamount, Hawaii.
Appl. Environ. Microbiol.
61:1555-1562[Abstract].
|
| 26.
|
Olsen, G. J.
1988.
Phylogenetic analysis using ribosomal RNA.
Methods Enzymol.
164:793-812[Medline].
|
| 27.
|
Oremland, R. S.,
J. S. Blum,
C. W. Culbertson,
P. T. Visscher,
L. G. Miller,
P. Dowdle, and F. E. Strohmaier.
1994.
Isolation, growth, and metabolism of an obligately anaerobic, selenate-respiring bacterium, strain SES-3.
Appl. Environ. Microbiol.
60:3011-3019[Abstract/Free Full Text].
|
| 28.
|
Pfenning, N., and H. Biebl.
1981.
The dissimilatory sulfur-reducing bacteria, p. 941-947.
In
M. P. Starr, H. Stolp, H. G. Truper, A. Balows, and H. G. Schlegel (ed.), The prokaryotes, vol. 1. Springer-Verlag, New York, N.Y.
|
| 29.
|
Polz, M. F., and C. M. Cavanaugh.
1995.
Dominance of one bacterial phylotype at a mid-Atlantic Ridge hydrothermal vent site.
Proc. Natl. Acad. Sci. USA
92:7232-7236[Abstract/Free Full Text].
|
| 30.
|
Porter, K. G., and Y. S. Feig.
1980.
The use of DAPI for identifying and counting aquatic microflora.
Limnol. Oceangr.
25:943-948.
|
| 31.
|
Prieur, D., and C. Jeanthon.
1987.
Preliminary study of heterotrophic bacteria isolated from deep sea hydrothermal vent invertebrates: Alvinella pompejana (Polychaete) and Bathymodiolus thermophilus (Bivalve).
Symbiosis
4:87-98.
|
| 32.
|
Prieur, D.,
S. Chamroux,
P. Durand,
G. Erauso,
P. Fera,
C. Jeanthon,
L. Le borgne,
G. Mével, and P. Vincent.
1990.
Metabolic diversity in epibiotic flora associated with the pompeii worms, Alvinella pompejana and Alvinella caudata (Polychaeta: Annelida) from deep-sea hydrothermal vents.
Mar. Biol.
106:361-367[CrossRef].
|
| 33.
|
Raguenes, G.,
P. Pignet,
G. Gauthier,
A. Peres,
R. Christen,
H. Rougeaux,
G. Barbier, and J. Guezennec.
1996.
Description of a new polymer-secreting bacterium from a deep-sea hydrothermal vent, Alteromonas macleodii subsp. fijiensis, and preliminary characterization of the polymer.
Appl. Environ. Microbiol.
62:67-73[Abstract].
|
| 34.
|
Rath, J.,
K. Y. Wu,
G. J. Herndl, and E. F. DeLong.
1998.
High phylogenetic diversity in a marine-snow-associated bacterial assemblage.
Aquat. Microb. Ecol.
14:261-269[CrossRef].
|
| 35.
|
Reysenbach, A. L.,
K. Longnecker, and J. Kirshtein.
2000.
Novel bacterial and archaeal lineages from an in situ growth chamber deployed at a mid-Atlantic Ridge hydrothermal vent.
Appl. Environ. Microbiol.
66:3798-3806[Abstract/Free Full Text].
|
| 36.
|
Rozan, T. F.,
S. M. Theberge, and G. Luther.
2000.
Quantifying elemental sulfur (S0), bisulfide (HS ) and polysulfides (Sx2 ) using a voltammetric method.
Anal. Chim. Acta
415:175-184[CrossRef].
|
| 37.
|
Schumacher, W.,
P. M. H. Kroneck, and N. Pfennig.
1992.
Comparative systematic study on "Spirillum" 5175, Campylobacter, and Wolinella species description of "Spirillum" 5175 as Sulfurospirillum deleyianum gen., nov. spec. nov.
Arch. Microbiol.
158:287-293[CrossRef].
|
| 38.
|
Slobodkin, A.,
B. J. Campbell,
S. C. Cary,
E. Bonch-Osmolovskaya, and C. Jeanthon.
2001.
Thermophilic Fe(III)-reducing microorganisms inhabit deep-sea hydrothermal vents on the east Pacific rise.
FEMS Microbiol. Ecol.
36:235-243[Medline].
|
| 39.
|
Smith, S. W.,
R. Overbeek,
G. Olsen,
C. Woese,
P. M. Gillevet, and W. Gilbert.
1992.
Genetic data environment and the Harvard genome database: genome mapping and sequencing.
Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.
|
| 40.
|
Snaidr, J.,
R. Amann,
I. Huber,
W. Ludwig, and K. H. Schleifer.
1997.
Phylogenetic analysis and in situ identification of bacteria in activated sludge.
Appl. Environ. Microbiol.
63:2884-2896[Abstract].
|
| 41.
|
Stetter, K. O.
1996.
Hyperthermophilic procaryotes.
FEMS Microbiol. Rev.
18:149-158[CrossRef].
|
| 42.
|
Stolz, J. F.,
D. J. Ellis,
J. S. Blum,
D. Ahmann,
D. R. Lovley, and R. S. Oremland.
1999.
Sulfurospirillum barnesii sp. nov. and Sulfurospirillum arsenophilum sp. nov., new members of the Sulfurospirillum clade of the epsilon Proteobacteria.
Int. J Syst. Bacteriol.
49:1177-1180[Abstract/Free Full Text].
|
| 43.
|
Taylor, C. D., and C. O. Wirsen.
1997.
Microbiology and ecology of filamentous sulfur formation.
Science
277:1483-1485[Abstract/Free Full Text].
|
| 44.
|
Taylor, C. D.,
C. O. Wirsen, and F. Gaill.
1999.
Rapid microbial production of filamentous sulfur mats at hydrothermal vents.
Appl. Environ. Microbiol.
65:2253-2255[Abstract/Free Full Text].
|
| 45.
|
Watanabe, K.,
Y. Kodama,
K. Syutsubo, and S. Harayama.
2000.
Molecular characterization of bacterial populations in petroleum-contaminated groundwater discharged from underground crude oil storage cavities.
Appl. Environ. Microbiol.
66:4803-4809[Abstract/Free Full Text].
|
| 46.
|
Widdel, F.
1983.
Methods for enrichment and pure culture isolation of filamentous gliding sulfate-reducing bacteria.
Arch. Microbiol.
134:282-285[CrossRef].
|
| 47.
|
Widdel, F., and F. Bak.
1992.
Gram-negative mesophilic sulfate-reducing bacteria, p. 3352-3378.
In
A. Balows, H. G. Truper, M. Dworkin, W. Harder, and K. H. Schleifer (ed.), The prokaryotes, vol. IV. Springer-Verlag, New York, N.Y.
|
Applied and Environmental Microbiology, October 2001, p. 4566-4572, Vol. 67, No. 10
0099-2240/01/$04.00+0 DOI: 10.1128/AEM.67.10.4566-4572.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
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[Full Text]
-
Brisbarre, N., Fardeau, M.-L., Cueff, V., Cayol, J.-L., Barbier, G., Cilia, V., Ravot, G., Thomas, P., Garcia, J.-L., Ollivier, B.
(2003). Clostridium caminithermale sp. nov., a slightly halophilic and moderately thermophilic bacterium isolated from an Atlantic deep-sea hydrothermal chimney. Int. J. Syst. Evol. Microbiol.
53: 1043-1049
[Abstract]
[Full Text]
-
Alazard, D., Dukan, S., Urios, A., Verhe, F., Bouabida, N., Morel, F., Thomas, P., Garcia, J.-L., Ollivier, B.
(2003). Desulfovibrio hydrothermalis sp. nov., a novel sulfate-reducing bacterium isolated from hydrothermal vents. Int. J. Syst. Evol. Microbiol.
53: 173-178
[Abstract]
[Full Text]
-
Podar, M., Mullineaux, L., Huang, H.-R., Perlman, P. S., Sogin, M. L.
(2002). Bacterial Group II Introns in a Deep-Sea Hydrothermal Vent Environment. Appl. Environ. Microbiol.
68: 6392-6398
[Abstract]
[Full Text]
-
Takai, K., Hirayama, H., Sakihama, Y., Inagaki, F., Yamato, Y., Horikoshi, K.
(2002). Isolation and Metabolic Characteristics of Previously Uncultured Members of the Order Aquificales in a Subsurface Gold Mine. Appl. Environ. Microbiol.
68: 3046-3054
[Abstract]
[Full Text]
-
Reysenbach, A.-L., Shock, E.
(2002). Merging Genomes with Geochemistry in Hydrothermal Ecosystems. Science
296: 1077-1082
[Abstract]
[Full Text]