Motility of
            <i>Marichromatium gracile</i>
            in Response to Light, Oxygen, and Sulfide

Thar, Roland; Kühl, Michael

doi:10.1128/aem.67.12.5410-5419.2001

Cited by 24 publications

(23 citation statements)

References 44 publications

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“…Nevertheless, they play an important role in the sulfur cycle of the chemocline, since they possess capabilities for both anaerobic photosynthetic sulfide oxidation and lithotrophic sulfide oxidation using oxygen (34). In addition, they can move to a zone in the chemocline that is more favorable for the acquisition of light or oxygen (50). In order to overcome this limitation, PCR-DGGE analysis using a primer set specific for narrower groups (e.g., the Chromatiaceae) might be effective in investigating minor but ecologically important populations (9).…”

Section: Discussionmentioning

confidence: 99%

Dominant Microbial Composition and Its Vertical Distribution in Saline Meromictic Lake Kaiike (Japan) as Revealed by Quantitative Oligonucleotide Probe Membrane Hybridization

Koizumi

Kojima

Fukui

2004

Appl Environ Microbiol

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Vertical distributions of dominant bacterial populations in saline meromictic Lake Kaiike were investigated throughout the water column and sediment by quantitative oligonucleotide probe membrane hybridization. Three oligonucleotide probes specific for the small-subunit (SSU) rRNA of three groups of Chlorobiaceae were newly designed. In addition, three general domain (Bacteria, Archaea, and Eukarya)-specific probes, two ␦-Proteobacteria-specific probes, a Chlorobiaceae-specific probe, and a Chloroflexi-specific probe were used after optimization of their washing conditions. The abundance of the sum of SSU rRNAs hybridizing with probes specific for three groups of Chlorobiaceae relative to total SSU rRNA peaked in the chemocline, accounting for up to 68%. The abundance of the ␦-proteobacterial SSU rRNA relative to total SSU rRNA rapidly increased just below the chemocline up to 29% in anoxic water and peaked at the 2-to 3-cm sediment depth at ca. 34%. The abundance of SSU rRNAs hybridizing with the probe specific for the phylum Chloroflexi relative to total SSU rRNA was highest (31 to 54%) in the top of the sediment but then steeply declined with depth and became stable at 11 to 19%, indicating the robust coexistence of sulfate-reducing bacteria and Chloroflexi in the top of the sediment. Any SSU rRNA of Chloroflexi in the water column was under the detection limit. The summation of the signals of group-specific probes used in this study accounted for up to 89% of total SSU rRNA, suggesting that the DGGE-oligonucleotide probe hybridization approach, in contrast to conventional culture-dependent approaches, was very effective in covering dominant populations.Lake Kaiike is a small saline meromictic lake on the seaward side of Kamikoshiki Island, in southwest Japan. A dense population of phototrophic purple sulfur bacteria has been observed in the chemocline of this lake (19,25,30) as well as in other meromictic lakes (32,33,51). A previous denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified small-subunit (SSU)-rRNA genes in the water column and sediment demonstrated the occurrence of drastic depth-related changes in the microbial community at the chemocline and the sediment-water interface (19). Some conspicuous DGGE bands whose sequences were related to Chlorobiaceae (also known as green sulfur bacteria) and sulfate-reducing bacteria (SRB) affiliated with the ␦-Proteobacteria were observed in anoxic water. An analysis of chloropigments also confirmed the predominance of members of the Chlorobiaceae in anoxic water and classified them as the brown variety of Chlorobiaceae, which were considered better adapted to lower light intensity than the green variety (54), owing to their possession of bacteriochlorophyll e (30). On the basis of phylogenetic analysis, Chlorobiaceae observed in Lake Kaiike could be divided into three groups, of which two were distinct from any isolated strains found to date. A comparison of DGGE banding patterns of the water column and sediment revealed that Chlorobiaceae ...

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Section: Discussionmentioning

confidence: 99%

Dominant Microbial Composition and Its Vertical Distribution in Saline Meromictic Lake Kaiike (Japan) as Revealed by Quantitative Oligonucleotide Probe Membrane Hybridization

Koizumi

Kojima

Fukui

2004

Appl Environ Microbiol

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“…Opposing oxygen-sulfide gradients were prepared by filling one half of the capillary with an agar plug prepared from filtered seawater amended with neutralized sulfide solution (2 to 5 mM H 2 S), whereas the other half of the capillary was filled with samples from the enrichment culture. A detailed description of this technique can be found in Thar and Kühl (33).…”

Section: Methodsmentioning

confidence: 99%

“…Typical examples of such microorganisms are the chemolithotrophic sulfide-oxidizing Beggiatoa spp. (23) and T. majus (20), but the phototrophic purple sulfur bacterium Marichromatium gracile has also been shown to aggregate in a thin layer at the oxic-anoxic interface under conditions of darkness (33). The filamentous Beggiatoa spp.…”

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confidence: 99%

Conspicuous Veils Formed by Vibrioid Bacteria on Sulfidic Marine Sediment

Thar

Kühl

2002

Appl Environ Microbiol

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We describe the morphology and behavior of a hitherto unknown bacterial species that forms conspicuous veils (typical dimensions, 30 by 30 mm) on sulfidic marine sediment. The new bacteria were enriched on complex sulfidic medium within a benthic gradient chamber in oxygen-sulfide countergradients, but the bacteria have so far not been isolated in pure culture, and a detailed characterization of their metabolism is still lacking. The bacteria are colorless, gram-negative, and vibrioid-shaped (1.3-to 2.5-by 4-to 10-m) cells that multiply by binary division and contain several spherical inclusions of poly-␤-hydroxybutyric acid. The cells have bipolar polytrichous flagella and exhibit a unique swimming pattern, rotating and translating along their short axis. Free-swimming cells showed aerotaxis and aggregated at ca. 2 M oxygen within opposing oxygen-sulfide gradients, where they were able to attach via a mucous stalk, forming a cohesive whitish veil at the oxic-anoxic interface. Bacteria attached to the veil kept rotating and adapted their stalk lengths dynamically to changing oxygen concentrations. The joint action of rotating bacteria on the veil induced a homogeneous water flow from the oxic water region toward the veil, whereby the oxygen uptake rate could be enhanced up to six times, as shown by model calculations. The veils showed a pronounced succession pattern. New veils were generated de novo within 24 h and had a homogeneous whitish translucent appearance. Bacterial competitors or eukaryotic predators were apparently kept away by the low oxygen concentration prevailing at the veil surface. Frequently, within 2 days the veil developed a honeycomb pattern of regularly spaced holes. After 4 days, most veils were colonized by grazing ciliates, leading to the fast disappearance of the new bacteria. Several-week-old veils finally developed into microbial mats consisting of green, purple, and colorless sulfur bacteria.Marine sediments and biofilms are characterized by opposing gradients of chemical compounds, which can react with each other via exergonic redox reactions (6, 14). The bestinvestigated gradient systems are sulfide-oxygen or sulfide-nitrate countergradients, and a variety of microorganisms which are specialized in efficiently utilizing the energy released by the redox reaction of the two gradient compounds have been described. Detailed physiological studies of species which can be cultured in homogeneous media, e.g., Thiobacillus spp., have been performed (18). However, many conspicuous gradient microorganisms in natural habitats (e.g., the colorless sulfide oxidizer Thiovulum majus) can be kept in the laboratory only as enrichment cultures, and only a few species have been successfully isolated in pure culture based on gradient media (24). While detailed physiological studies are still lacking, the behavior and motility of gradient microorganisms, especially of the relatively large and easily identifiable colorless and photosynthetic sulfur-oxidizing bacteria, have been described in the literature...

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“…There are detailed studies of the chemotactic behavior of various swimming sulfur bacteria and of the formation of mats and veils of these organisms (Thar & Fenchel, 2001, 2005Thar & Kühl, 2001;Fenchel & Thar, 2004). Some swimming sulfur bacteria reverse their swimming direction at a critical oxygen concentration of 1-10 mM oxygen (Thar & Fenchel, 2005).…”

Section: Introductionmentioning

confidence: 99%

Motility patterns of filamentous sulfur bacteria, Beggiatoa spp.

Dunker

Røy²,

Kamp

et al. 2011

FEMS Microbiology Ecology

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The large sulfur bacteria, Beggiatoa spp., live on the oxidation of sulfide with oxygen or nitrate, but avoid high concentrations of both sulfide and oxygen. As gliding filaments, they rely on reversals in the gliding direction to find their preferred environment, the oxygen–sulfide interface. We observed the chemotactic patterns of single filaments in a transparent agar medium and scored their reversals and the glided distances between reversals. Filaments within the preferred microenvironment glided distances shorter than their own length between reversals that anchored them in their position as a microbial mat. Filaments in the oxic region above the mat or in the sulfidic, anoxic region below the mat glided distances longer than the filament length between reversals. This reversal behavior resulted in a diffusion‐like spreading of the filaments. A numerical model of such gliding filaments was constructed based on our observations. The model was applied to virtual filaments in the oxygen‐ and sulfide‐free zone of the sediment, which is a main habitat of Beggiatoa in the natural environment. The model predicts a long residence time of the virtual filament in the suboxic zone and explains why Beggiatoa accumulate high nitrate concentrations in internal vacuoles as an alternative electron acceptor to oxygen.

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Motility of Marichromatium gracile in Response to Light, Oxygen, and Sulfide

Cited by 24 publications

References 44 publications

Dominant Microbial Composition and Its Vertical Distribution in Saline Meromictic Lake Kaiike (Japan) as Revealed by Quantitative Oligonucleotide Probe Membrane Hybridization

Dominant Microbial Composition and Its Vertical Distribution in Saline Meromictic Lake Kaiike (Japan) as Revealed by Quantitative Oligonucleotide Probe Membrane Hybridization

Conspicuous Veils Formed by Vibrioid Bacteria on Sulfidic Marine Sediment

Motility patterns of filamentous sulfur bacteria, Beggiatoa spp.

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