Achromatium oxaliferum Understanding the Unmistakable

Head, Ian M; Gray, Neil; Howarth, R; Pickup, Roger W.; Clarke, Ken J.; Jones, J. G.

doi:10.1007/978-1-4615-4187-5_1

Cited by 28 publications

(73 citation statements)

References 62 publications

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“…This indicates that environmental selection determines the composition of the Achromatium community in the two lakes. This experimental finding is consistent with observed environmental differences between the sites (Head et al, 2000) and some limited information on functional differences between the geographically separated Achromatium populations. RY has low sulfate (15-168 nmol cm À3 ) and high organic carbon (14.8-15.9 wt%) concentrations, Measured sulfate reduction rates are in the range of 10-300 nmol cm À3 per day and reduced sulfur species concentrations range from 3.4 to 9.5 mmol cm À3 .…”

Section: Discussionsupporting

confidence: 90%

“…Validation of the experimental approach It has been shown in experimental microcosms similar to those used here that redox gradients and the small-scale distribution of Achromatium species are rapidly re-established when microcosms are re-constituted from bulk sediments (Head et al, 2000). Furthermore, Achromatium community composition is maintained when reconstituted sediments are incubated (as in this study) with oxic overlying water (Gray et al, 2004).…”

Section: Discussionmentioning

confidence: 65%

“…Achromatium are large uncultured sulfur-oxidizing bacteria found in freshwater sediments (Gray and Head, 1999;Head et al, 2000). Although Achromatium are relatively large compared to most bacteria, their size is fairly typical of many eukaryotic microorganisms and well below the size limitation proposed to be permissive for effective dispersal by agents such as wind, animals and birds (Finlay, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…As a result, Achromatium cannot form conspicuous mats and cannot rely on the diffusive flux of free sulfide, as do other giant sulfur bacteria. Instead, they are distributed throughout the zone of sulfate reduction and may even use other reduced sulfur resources (Gray et al, 1997;Gray and Head, 1999;Head et al, 2000). Achromatium communities comprise coexisting species, some of which exploit different redoxdefined niches as a basis for coexistence (Gray et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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The biogeographical distribution of closely related freshwater sediment bacteria is determined by environmental selection

et al. 2007

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The role of environmental selection in governing the structure of communities of freshwater sulfur bacteria (Achromatium spp) was experimentally tested by mixing sediments from two geographically separated lakes (Rydal Water (RY) and Hell Kettles (HK)) that harboured Achromatium spp. Community profiles of Achromatium spp in sediment microcosms at day 0 and after 60 days were compared to determine whether initial Achromatium community composition or subsequent selection by the sediment environment had greater influence in dictating the final Achromatium community structure. It was found that Achromatium spp from the HK community became established in mixed sediments at the expense of members of the RY community. This selection for the HK Achromatium community was more pronounced when sediment composition was manipulated to resemble HK sediments. Our findings definitively demonstrate that environmental selection is the primary determinant of Achromatium community structure in these sediments.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The biogeographical distribution of closely related freshwater sediment bacteria is determined by environmental selection

et al. 2007

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“…Their most conspicuous characteristic is the accumulation of numerous large inclusions filling the majority of the cell that were first described as calcium oxalate, giving the type species Achromatium oxaliferum its name, but which were later recognized as colloidal calcite (West and Griffiths, 1913;Bersa, 1920;Head et al, 1996). Recently, cyanobacteria (Gloeobacterales) were found to form amorphous calcium-magnesium-strontium-barium carbonate inclusions (Couradeau et al, 2012); however, the massive accumulation of CaCO 3 in Achromatium is still a unique peculiarity in the microbial world (Head et al, 2000;Gray and Head, 2014). The biological function of internal calcite is under investigation, and hypotheses include its usage as buffer, a source of CO 2 or a mechanism of buoyancy regulation (Gray, 2006, reviewed in Head et al, 2000.…”

Section: Introductionmentioning

confidence: 99%

Calcite-accumulating large sulfur bacteria of the genus Achromatium in Sippewissett Salt Marsh

et al. 2015

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Large sulfur bacteria of the genus Achromatium are exceptional among Bacteria and Archaea as they can accumulate high amounts of internal calcite. Although known for more than 100 years, they remain uncultured, and only freshwater populations have been studied so far. Here we investigate a marine population of calcite-accumulating bacteria that is primarily found at the sediment surface of tide pools in a salt marsh, where high sulfide concentrations meet oversaturated oxygen concentrations during the day. Dynamic sulfur cycling by phototrophic sulfide-oxidizing and heterotrophic sulfate-reducing bacteria co-occurring in these sediments creates a highly sulfidic environment that we propose induces behavioral differences in the Achromatium population compared with reported migration patterns in a low-sulfide environment. Fluctuating intracellular calcium/sulfur ratios at different depths and times of day indicate a biochemical reaction of the salt marsh Achromatium to diurnal changes in sedimentary redox conditions. We correlate this calcite dynamic with new evidence regarding its formation/mobilization and suggest general implications as well as a possible biological function of calcite accumulation in large bacteria in the sediment environment that is governed by gradients. Finally, we propose a new taxonomic classification of the salt marsh Achromatium based on their adaptation to a significantly different habitat than their freshwater relatives, as indicated by their differential behavior as well as phylogenetic distance on 16S ribosomal RNA gene level. In future studies, whole-genome characterization and additional ecophysiological factors could further support the distinctive position of salt marsh Achromatium.

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Achromatium

Babenzien¹,

Glöckner²,

Head³

2015

Bergey's Manual of Systematics of Archaea and Bacteria

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A.chro.ma' ti.um . Gr. pref. a not; Gr. n. chromatium color, paint; M.L. neut. n. Achromatium that which is not colored. Proteobacteria / Gammaproteobacteria / Thiotrichales / Thiotrichaceae / Achromatium Spherical to ovoid or cylindrical unicells with hemispherical ends. In natural populations, cells of widely different sizes appear . Cells vary in size from spheres of about 10 µm in diameter to giant cylindrical forms up to 30 × 125 µm (extremes are dividing stages); cells are on average 15 × 50 μm . Many size classes may be present within a sample. However, genetically different sub‐populations that overlap in their dimensions can occur in a single habitat. Division of cells by binary constriction. Gram negative. Calcium carbonate (calcite) is deposited intracellularly . Additionally, the cells contain globules of S 0 . The mol % G + C of the DNA is : not known. Type species : Achromatium oxaliferum Schewiakoff 1893, 1.

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Achromatium oxaliferum Understanding the Unmistakable

Cited by 28 publications

References 62 publications

The biogeographical distribution of closely related freshwater sediment bacteria is determined by environmental selection

The biogeographical distribution of closely related freshwater sediment bacteria is determined by environmental selection

Calcite-accumulating large sulfur bacteria of the genus Achromatium in Sippewissett Salt Marsh

Achromatium

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