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Whitaker AH, Austin RE, Holden KL, Jones JL, Michel FM, Peak D, Thompson A, Duckworth OW. The Structure of Natural Biogenic Iron (Oxyhydr)oxides Formed in Circumneutral pH Environments. GEOCHIMICA ET COSMOCHIMICA ACTA 2021; 308:237-255. [PMID: 34305159 PMCID: PMC8294128 DOI: 10.1016/j.gca.2021.05.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Biogenic iron (Fe) (oxyhydr)oxides (BIOS) partially control the cycling of organic matter, nutrients, and pollutants in soils and water via sorption and redox reactions. Although recent studies have shown that the structure of BIOS resembles that of two-line ferrihydrite (2LFh), we lack detailed knowledge of the BIOS local coordination environment and structure required to understand the drivers of BIOS reactivity in redox active environments. Therefore, we used a combination of microscopy, scattering, and spectroscopic methods to elucidate the structure of BIOS sampled from a groundwater seep in North Carolina and compare them to 2LFh. We also simulated the effects of wet-dry cycles by varying sample preparation (e.g., freezing, flash freezing with freeze drying, freezing with freeze drying and oven drying). In general, the results show that both the long- and short-range ordering in BIOS are structurally distinct and notably more disordered than 2LFh. Our structure analysis, which utilized Fe K-edge X-ray absorption spectroscopy, Mössbauer spectroscopy, X-ray diffraction, and pair distribution function analyses, showed that the BIOS samples were more poorly ordered than 2LFh and intimately mixed with organic matter. Furthermore, pair distribution function analyses resulted in coherent scattering domains for the BIOS samples ranging from 12-18 Å, smaller than those of 2LFh (21-27 Å), consistent with reduced ordering. Additionally, Fe L-edge XAS indicated that the local coordination environment of 2LFh samples consisted of minor amounts of tetrahedral Fe(III), whereas BIOS were dominated by octahedral Fe(III), consistent with depletion of the sites due to small domain size and incorporation of impurities (e.g., organic C, Al, Si, P). Within sample sets, the frozen freeze dried and oven dried sample preparation increased the crystallinity of the 2LFh samples when compared to the frozen treatment, whereas the BIOS samples remained more poorly crystalline under all sample preparations. This research shows that BIOS formed in circumneutral pH waters are poorly ordered and more environmentally stable than 2LFh.
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Affiliation(s)
- Andrew H. Whitaker
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Robert E. Austin
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Kathryn L. Holden
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Jacob L. Jones
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - F. Marc Michel
- Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24060, USA
| | - Derek Peak
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada
| | - Aaron Thompson
- Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia 30602, USA
| | - Owen W. Duckworth
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA
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Bonnineau C, Artigas J, Chaumet B, Dabrin A, Faburé J, Ferrari BJD, Lebrun JD, Margoum C, Mazzella N, Miège C, Morin S, Uher E, Babut M, Pesce S. Role of Biofilms in Contaminant Bioaccumulation and Trophic Transfer in Aquatic Ecosystems: Current State of Knowledge and Future Challenges. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 253:115-153. [PMID: 32166435 DOI: 10.1007/398_2019_39] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In freshwater environments, microbial assemblages attached to submerged substrates play an essential role in ecosystem processes such as primary production, supported by periphyton, or organic matter decomposition, supported by microbial communities attached to leaf litter or sediments. These microbial assemblages, also called biofilms, are not only involved in nutrients fluxes but also in contaminants dynamics. Biofilms can accumulate metals and organic contaminants transported by the water flow and/or adsorbed onto substrates. Furthermore, due to their high metabolic activity and their role in aquatic food webs, microbial biofilms are also likely to influence contaminant fate in aquatic ecosystems. In this review, we provide (1) a critical overview of the analytical methods currently in use for detecting and quantifying metals and organic micropollutants in microbial biofilms attached to benthic substrata (rocks, sediments, leaf litter); (2) a review of the distribution of those contaminants within aquatic biofilms and the role of these benthic microbial communities in contaminant fate; (3) a set of future challenges concerning the role of biofilms in contaminant accumulation and trophic transfers in the aquatic food web. This literature review highlighted that most knowledge on the interaction between biofilm and contaminants is focused on contaminants dynamics in periphyton while technical limitations are still preventing a thorough estimation of contaminants accumulation in biofilms attached to leaf litter or sediments. In addition, microbial biofilms represent an important food resource in freshwater ecosystems, yet their role in dietary contaminant exposure has been neglected for a long time, and the importance of biofilms in trophic transfer of contaminants is still understudied.
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Affiliation(s)
| | - Joan Artigas
- Université Clermont Auvergne, CNRS, Laboratoire Microorganismes: Génome et Environnement (LMGE), Clermont-Ferrand, France
| | | | | | - Juliette Faburé
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, Versailles, France
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Field HR, Whitaker AH, Henson JA, Duckworth OW. Sorption of copper and phosphate to diverse biogenic iron (oxyhydr)oxide deposits. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 697:134111. [PMID: 31487593 DOI: 10.1016/j.scitotenv.2019.134111] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 08/23/2019] [Accepted: 08/24/2019] [Indexed: 06/10/2023]
Abstract
Iron (Fe) transformations partially control the biogeochemical cycling of biologically and environmentally important elements, such as carbon (C), nitrogen (N), phosphorus (P), and trace metals. In marine and freshwater environments, iron oxidizing bacteria commonly promote the oxidation of ferrous iron (Fe(II)) at circumneutral oxic-anoxic interfaces, resulting in the formation of mineral-organic composites known as biogenic Fe(III) (oxyhydr)oxides (BIOS). Previous studies have examined the microbial ecology, composition, morphology, and sorption reactivity of BIOS. However, a broad survey of BIOS properties and sorption reactivity is lacking. To further explore these relationships, this study utilized X-ray absorption spectroscopy (XAS) to characterize the Fe mineral species, acid digestions and elemental analysis to determine composition, Brunauer-Emmett-Teller (BET) analysis to measure specific surface area, and copper (Cu) and phosphorus (P) adsorption experiments at concentrations designed to measure maximum sorption to evaluate reactivity of BIOS samples collected in lakes and streams of the North Carolina Piedmont. Sample composition varied widely, with Fe and C content ranging from 6.3 to 34% and 3.4-13%, respectively. XAS spectra were best fit with 42-100% poorly crystalline Fe (oxyhydr)oxides, with the remainder composed of crystalline Fe minerals and organic complexes. On a sorbent mass basis, Cu and P sorption varied by a factor of two and 15, respectively. Regression analyses reveal interrelationships between physicochemical properties, and suggest that differences in P binding are driven by sorption to Fe(III) (oxyhydr)oxide surfaces. In total, results suggest that the physical and chemical characteristics of organic and Fe(III) (oxyhydr)oxide phases in BIOS interplay to control the sorption of solutes, and thus influence nutrient and contaminant cycling in soil and natural waters.
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Affiliation(s)
- Hannah R Field
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695-7620, USA; Department of Geological and Environmental Sciences at Appalachian State University, Boone, NC 28608-2067, USA
| | - Andrew H Whitaker
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695-7620, USA
| | - Joshua A Henson
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695-7620, USA
| | - Owen W Duckworth
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695-7620, USA.
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Lakshman Kumar A, Eashwar M, Sreedhar G, Vengatesan S, Prabu V, Shanmugam VM. Portraying manganese biofilms via a merger of EPR spectroscopy and cathodic polarization. BIOFOULING 2019; 35:768-784. [PMID: 31530181 DOI: 10.1080/08927014.2019.1658747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 08/01/2019] [Accepted: 08/16/2019] [Indexed: 06/10/2023]
Abstract
Microbial biofilms on stainless steel surfaces exposed to water from a freshwater pond were dominated by manganese-oxidizing bacteria, as initially diagnosed by microscopy and elemental analysis. The application of electron paramagnetic resonance (EPR) spectroscopy revealed conspicuous sextet (six-line) patterns that intensified with immersion time, implying the gradual accumulation of Mn(II) in the biofilms. Correspondingly, cathodic polarization designated the manganese oxide (MnOx) reduction peak in the form of a distinctive 'nose', which grew increasingly more negative with biofilm growth. The progressive expansion of cathodic current densities and the concurrent area-under-the-curve also allowed the quantification of microbially mediated MnOx deposition. Furthermore, the merger of EPR and cathodic polarization techniques yielded key insights, in tandem with Mn speciation data, into the pathways of microbial manganese transformations in biofilms, besides providing meaningful interpretations of prevailing literature. Accordingly, the natural freshwater biofilm was inferred as one supporting a complete manganese cycle encompassing multiple redox states.
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Affiliation(s)
- A Lakshman Kumar
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
- Biofilms and Biogeochemistry Group, Corrosion and Materials Protection Division, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - M Eashwar
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
- Biofilms and Biogeochemistry Group, Corrosion and Materials Protection Division, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - G Sreedhar
- Electro-Pyrometallurgy Division, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - S Vengatesan
- Electro-Inorganic Chemicals Division, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - V Prabu
- Central Instrumentation Facility, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
| | - V M Shanmugam
- Central Instrumentation Facility, CSIR-Central Electrochemical Research Institute , Karaikudi , Tamil Nadu , India
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Lawrence JR, Swerhone GDW, Neu TR. Visualization of the Sorption of Nickel within Exopolymer Microdomains of Bacterial Microcolonies Using Confocal and Scanning Electron Microscopy. Microbes Environ 2019; 34:76-82. [PMID: 30799318 PMCID: PMC6440736 DOI: 10.1264/jsme2.me18134] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The sorption and distribution of nickel, a common metal contaminant in aquatic systems, were assessed in bacterial microcolonies using a combination of fluorescent staining with Newport Green and confocal laser scanning microscopy (CLSM) with confirmation by scanning electron microscopy (SEM) and X-ray microprobe analyses. CLSM with Newport Green, selected fluor-conjugated lectins, and DNA staining allowed for the discrimination of the microdomains present in the microcolony exopolymeric matrix and detection of bound nickel. This approach avoided the artefacts associated with drying and fixation required by analytical electron microscopy. The results obtained indicated that specific microcolonies within river biofilms sorbed nickel within limited microdomains present in the complex tripartite exopolymeric matrix surrounding bacterial cells. Sorption occurred such that nickel was concentrated within the exopolymeric matrix, but not directly associated with cells. These microdomains appeared to have neutral pH and be dominated by negatively charged residues favoring the sorption of nickel and other cations. These results also suggest an important role for specific community members in the sorption and concentration of metals in aquatic biofilm communities.
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Affiliation(s)
| | | | - Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research-UFZ
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Whitaker AH, Peña J, Amor M, Duckworth OW. Cr(vi) uptake and reduction by biogenic iron (oxyhydr)oxides. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:1056-1068. [PMID: 29922797 DOI: 10.1039/c8em00149a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The mobility and toxicity of chromium (Cr) in soil and water systems are largely controlled by its oxidation state and interactions with solid phases. Relative to abiotic minerals, biogenic iron (Fe) (oxyhydr)oxides (BIOS) may enhance Cr(vi) adsorption and reduction due to their poorly ordered structures, large surface areas, and incorporation of cell derived organic matter. To determine the extent and mechanisms of the reaction between Cr(vi) and BIOS, sorption isotherm and kinetic studies were conducted using two-line ferrihydrite, BIOS, and BIOS amended with 0.135 M ferrozine (an Fe(ii) chelator). X-ray absorption near edge structure (XANES) spectroscopy of BIOS reacted with Cr(vi) showed approximately 50% reduction of the total sorbed Cr from Cr(vi) to Cr(iii) after 14 days of exposure. Sorbed Cr(iii) was best fit with an organic carboxylate complex after 1 d of reaction, but after 7 d mineral-associated Cr(iii) was the predominant form. In the presence of ferrozine, Cr(vi) reduction by BIOS was inhibited, confirming a key role for Fe(ii) as the Cr(vi) reductant. However, the lack of a 3 : 1 reaction stoichiometry between Fe(ii) and Cr(iii) produced suggests roles for reaction with organic matter and Cr(v) autoreduction in Cr(iii) production. This study thus elucidates an unrecognized mechanism of Cr sequestration by ubiquitous natural Fe (oxyhydr)oxide deposits. Furthermore, the redox transformation of mobile Cr(vi) to less soluble Cr(iii) species observed in our study implies that biogenic Fe (oxyhydr)oxides in soils and natural waters may naturally attenuate Cr(vi) concentrations through sorption and reduction processes, thus limiting its transport to downstream environments.
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Affiliation(s)
- Andrew H Whitaker
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695-7620, USA.
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Lawrence JR, Swerhone GDW, Kuhlicke U, Neu TR. In situevidence for metabolic and chemical microdomains in the structured polymer matrix of bacterial microcolonies. FEMS Microbiol Ecol 2016; 92:fiw183. [DOI: 10.1093/femsec/fiw183] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2016] [Indexed: 11/13/2022] Open
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Liu X, Eusterhues K, Thieme J, Ciobota V, Höschen C, Mueller CW, Küsel K, Kögel-Knabner I, Rösch P, Popp J, Totsche KU. STXM and NanoSIMS investigations on EPS fractions before and after adsorption to goethite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:3158-3166. [PMID: 23451805 DOI: 10.1021/es3039505] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Extracellular polymeric substances (EPS) are expected to be an important source for the formation of mineral-organic associations in soil. Because such formations affect the composition of mobile and immobile organic matter as well as the reactivity of minerals, we investigated the composition of EPS before and after adsorption to goethite. Raman measurements on EPS extracted from Bacillus subtilis distinguished four fractions rich in proteins, polysaccharides, lipids, or lipids and proteins. Scanning transmission X-ray microscopy identified three different EPS-fractions that varied in their composition in proteins, nonaromatic proteins, and polysaccharides. Reaction of EPS with goethite led to a preferential adsorption of lipids and proteins. The organic coverage was heterogeneous, consisting of ~100 × 200 nm large patches of either lipid-rich or protein-rich material. Nanoscale secondary ion mass spectrometry showed a strong S enrichment in aggregates of ~400 nm in the goethite adsorbed EPS. From our simplified model system, we learned that only a small portion (<10%) of EPS was immobilized via adsorption to goethite. This fraction formed a coating of subμm spaced protein-rich and lipid-rich domains, i.e., of two materials which will strongly differ in their reactive sites. This will finally affect further adsorption, the particle mobility and eventually also colloidal stability.
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Affiliation(s)
- Xinran Liu
- Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Germany
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Isotope fractionations in the biosynthesis of cell components by different fungi: a basis for environmental carbon flux studies. FEMS Microbiol Ecol 2012; 46:121-8. [PMID: 19719589 DOI: 10.1016/s0168-6496(03)00203-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Abstract The isotope fractionation of carbon from substrates possessing different isotope ratios into fatty acids of polar lipids and amino acids was determined for four different fungi (Rhizopus arrhizus, Mortierella isabellina, Fusarium solani, Aspergillus niger). Carbon isotope ratios of fungi closely followed that of the substrates. Palmitic acid (C16:0), derived from phospholipids, did not display a large carbon isotope fractionation against the substrate. Stearic acid (C18:0), however, was depleted in (13)C against C16:0 in all strains. The desaturation of C18:0 to oleic acid (C18:1omega9) had little effect on the carbon isotope ratio. The subsequent desaturation of C18:1omega9 to linolic acid (C18:2omega6,9) enriched the resulting C18:2omega6,9 by +3.9 per thousand and varied little among strains. This result is important because C18:2omega6,9 is often used as a biomarker in environmental studies. Most amino acids were enriched in (13)C compared to the substrates, but isoleucine and lysine were close to the isotope ratio of the substrate and phenylalanine and leucine were depleted. Interestingly, the carbon isotope ratios of many amino acids differed significantly among different species. A discriminant analysis based on the isotope ratio of four amino acids (Thr, Ile, Phe, Val) resolved the two phyla in the first discriminant function and all four strains in the first two discriminant functions and confirmed a taxon-specific manner of isotope fractionation. The derived rules provide the basis for the use of stable isotopes in environmental studies to elucidate the role of fungi in the carbon flow in the environment.
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Jaroch D, McLamore E, Zhang W, Shi J, Garland J, Banks MK, Porterfield DM, Rickus JL. Cell-mediated deposition of porous silica on bacterial biofilms. Biotechnol Bioeng 2011; 108:2249-60. [DOI: 10.1002/bit.23195] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 04/11/2011] [Accepted: 04/22/2011] [Indexed: 11/07/2022]
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Megacities as sources for pathogenic bacteria in rivers and their fate downstream. Int J Microbiol 2010; 2011. [PMID: 20885968 PMCID: PMC2946570 DOI: 10.1155/2011/798292] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 07/09/2010] [Accepted: 07/19/2010] [Indexed: 12/27/2022] Open
Abstract
Poor sanitation, poor treatments of waste water, as well as catastrophic floods introduce pathogenic bacteria into rivers, infecting and killing many people. The goal of clean water for everyone has to be achieved with a still growing human population and their rapid concentration in large cities, often megacities. How long introduced pathogens survive in rivers and what their niches are remain poorly known but essential to control water-borne diseases in megacities. Biofilms are often niches for various pathogens because they possess high resistances against environmental stress. They also facilitate gene transfers of antibiotic resistance genes which become an increasing health problem. Beside biofilms, amoebae are carriers of pathogenic bacteria and niches for their survival. An overview about our current understanding of the fate and niches of pathogens in rivers, the multitude of microbial community interactions, and the impact of severe flooding, a prerequisite to control pathogens in polluted rivers, is given.
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Miyata N, Sugiyama D, Tani Y, Tsuno H, Seyama H, Sakata M, Iwahori K. Production of biogenic manganese oxides by repeated-batch cultures of laboratory microcosms. J Biosci Bioeng 2007; 103:432-9. [PMID: 17609158 DOI: 10.1263/jbb.103.432] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Accepted: 02/14/2007] [Indexed: 11/17/2022]
Abstract
We investigated the production of manganese (Mn) oxides using repeated-batch bioreactors maintained over long periods under laboratory conditions. Freshwater epilithic biofilms were used as the initial inocula. The bioreactors yielded suspended solids that could remove 0.1 mM dissolved Mn(II) within a few days. Chemical titration, X-ray absorption near-edge structure spectroscopy, and X-ray diffraction analysis revealed that the Mn(II) had been converted to poorly crystallized layer-type Mn(IV) oxides, which were similar to known biogenic Mn oxides from pure bacterial cultures. Spherical or rod-shaped Mn microconcretions occurred in the suspended solids; transmission electron microscopy showed that these structures likely resulted from the microbial activity but not represent living cells. Instead, the presence of encapsulated, sheathed, and hyphal budding cells in the suspended solids indicated that a range of Mn-depositing bacteria contributed to the Mn oxide formation. To our knowledge, our data represent the first observation of production of such Mn oxides in a laboratory microcosm wherein a range of Mn-depositing bacteria coexist. The fact that sorption of trace Zn(II) and Ni(II) ions onto the suspended solids co-occurred with the removal of dissolved Mn(II) emphasizes the important role of Mn-oxidizing microorganisms in the fates of trace or contaminant metals in the aquatic environment.
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Affiliation(s)
- Naoyuki Miyata
- Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga, Shizuoka, Japan.
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Lawrence JR, Swerhone GDW, Kuhlicke U, Neu TR. In situ evidence for microdomains in the polymer matrix of bacterial microcolonies. Can J Microbiol 2007; 53:450-8. [PMID: 17538657 DOI: 10.1139/w06-146] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Confocal laser scanning microscopy and fluorescent lectin-binding analyses (FLBA) were used to study the form, arrangement, and composition of exopolymeric substances (EPS) surrounding naturally occurring microcolonies in biofilms. FLBA, using multiple lectin staining and multichannel imaging, indicated that the EPS of many microcolonies exhibit distinct multiple binding regions. A common pattern in the microcolonies is a three zone arrangement with cell-associated, intercellular, and an outer layer of EPS covering the exterior of the colony. Differential binding of lectins suggests that there are differences in the glycoconjugate composition or their arrangement in the EPS of microcolonies. The combination of FLBA with fluorescent in situ hybridization (FISH) indicates that the colonies consist of the major groups, α- and β-Proteobacteria. It is suggested that the EPS arrangement observed provides a physical structuring mechanism that can segregate extracellular activities at the microscale.
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Affiliation(s)
- J R Lawrence
- National Water Research Institute, 11 Innovation Boulevard, Saskatoon, SK S7N3H5, Canada.
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Dynes JJ, Tyliszczak T, Araki T, Lawrence JR, Swerhone GDW, Leppard GG, Hitchcock AP. Speciation and quantitative mapping of metal species in microbial biofilms using scanning transmission X-ray microscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:1556-65. [PMID: 16568770 DOI: 10.1021/es0513638] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A scanning transmission X-ray microscope illuminated with synchrotron light was used to investigate the speciation and spatial distributions of metals in a microbial biofilm cultivated from river water. Metal 2p absorption edge signals were used to provide metal speciation (through shapes of the absorption spectra) and quantitative spatial distributions of the metal species. This paper presents sample data and describes methods for extracting quantitative maps of metal species from image sequences recorded in the region of the metal 2p edges. Comparisons were made with biochemical characterization of the same region using images recorded at the C 1s and O 1s edges. The method is applied to detailed quantitative analysis of ferrous and ferric iron in a river biofilm, in concert with mapping Ni(II) and Mn(II) species in the same region. The distributions of the metal species are discussed in the context of the biofilm structure. These results demonstrate that soft X-ray STXM measurements at the metal 2p absorption edges can be used to speciate metals and to provide quantitative spatial distribution maps for metal species in environmental samples with 50 nm spatial resolution.
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Affiliation(s)
- James J Dynes
- Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, Canada L8S 4M1
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Bohuss I, Rékasi T, Szikora S, Barkács K, Záray G, Ács É. Interaction of acetochlor and atrazine with natural freshwater biofilms grown on polycarbonate substrate in lake Velence (Hungary). Microchem J 2005. [DOI: 10.1016/j.microc.2004.08.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Dong D, Hua X, Li Y, Zhang J, Yan D. Cd adsorption properties of components in different freshwater surface coatings: the important role of ferromanganese oxides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2003; 37:4106-4112. [PMID: 14524442 DOI: 10.1021/es034070s] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Surface coatings developed in different natural waters were used to study the role of the composition of surface coatings in controlling Cd adsorption in aquatic environments. To investigate the adsorption property of each component, the method of extraction techniques followed by Cd adsorption and statistical analysis were employed. Hydroxylamine hydrochloride was used to remove Mn oxides selectively, sodium dithionite was used to remove Mn and Fe oxides, and oxalic acid was used to remove most metal oxides and part of the organic material. Adsorption of Cd to surface coatings was measured before and after extraction under controlled laboratory conditions. The observed Cd adsorptions to unextracted and extracted surface coatings were analyzed using nonlinear least-squares fitting to estimate the adsorption property of each surface coating constituent. In different waters, the relative contribution to Cd adsorption of each component was different, but in all the waters studied, ferromanganese oxides contributed most with lesser roles indicated for organic phase and Al oxides. The Cd adsorption ability of manganese oxides was significantly higher than that of the other components.
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Affiliation(s)
- Deming Dong
- College of Environment and Resources, Jilin University, 115 Jiefang Road, Changchun 130023, People's Republic of China.
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Bohuss I, Bozóki J, Barkács K, Záray G. Comparison of sample preparation methods applied for determination of atrazine in freshwater biofilms by gas chromatograph-mass spectrometer system. Microchem J 2003. [DOI: 10.1016/s0026-265x(03)00004-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Lawrence JR, Kopf G, Headley JV, Neu TR. Sorption and metabolism of selected herbicides in river biofilm communities. Can J Microbiol 2001; 47:634-41. [PMID: 11547883 DOI: 10.1139/w01-061] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, biofilms were grown in rotating annular bioreactors with river water as inoculum and sole source of nutrients. The herbicides atrazine and diclofop methyl were applied to the bioreactors, while an identical reactor acted as a control. Biofilm structure was visualized using specific fluorescent probes in conjunction with confocal laser scanning microscopy. The concentration of both herbicides in the bulk water phase followed the pattern of application. Atrazine and metabolites were detected in biofilm samples using direct insertion probe tandem mass spectrometry (DIP-MS/MS) and only trace levels were detected after the addition phase. Monoclonal antibody (MAb) studies indicated that sorption of atrazine was associated with a unique microcolony type. In contrast, diclofop and metabolites reached a maximum level in the biofilm at the end of the addition phase and persisted in the biofilm. Experiments with 14C-labeled atrazine and diclofop methyl indicated that mineralization of these compounds to CO2 (<1%) occurred in the river biofilms. Thus, both herbicides were sorbed and metabolized by the river biofilm community and detected in biofilms when they were not detected in the bulk water phase. These results indicate that biofilms and specific community members may act as a sink for herbicides, and that this should be taken into account in terms of both sampling and studies of the environmental chemodynamics of contaminants.
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Affiliation(s)
- J R Lawrence
- National Water Research Institute, Saskatoon, SK, Canada.
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Guggenheim M, Shapiro S, Gmür R, Guggenheim B. Spatial arrangements and associative behavior of species in an in vitro oral biofilm model. Appl Environ Microbiol 2001; 67:1343-50. [PMID: 11229930 PMCID: PMC92733 DOI: 10.1128/aem.67.3.1343-1350.2001] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The spatial arrangements and associative behavior of Actinomyces naeslundii, Veillonella dispar, Fusobacterium nucleatum, Streptococcus sobrinus, and Streptococcus oralis strains in an in vitro model of supragingival plaque were determined. Using species-specific fluorescence-labeled antibodies in conjunction with confocal laser scanning microscopy, the volumes and distribution of the five strains were assessed during biofilm formation. The volume-derived cell numbers of each strain correlated well with respective culture data. Between 15 min and 64 h, populations of each strain increased in a manner reminiscent of batch growth. The microcolony morphologies of all members of the consortium and their distributions within the biofilm were characterized, as were interspecies associations. Biofilms formed 15 min after inoculation consisted principally of single nonaggregated cells. All five strains adhered strongly to the saliva-conditioned substratum, and therefore, coadhesion played no role during the initial phase of biofilm formation. This observation does not reflect the results of in vitro coaggregation of the five strains, which depended upon the nature of the suspension medium. While the possibility cannot be excluded that some interspecies associations observed at later stages of biofilm formation were initiated by coadhesion, increase in bacterial numbers appeared to be largely a growth phenomenon regulated by the prevailing cultivation conditions.
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Affiliation(s)
- M Guggenheim
- Institute for Oral Microbiology and General Immunology, Center for Dental and Oral Medicine and Maxillofacial Surgery, University of Zürich, CH-8028 Zürich, Switzerland
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Samrakandi MM, Roques C, Michel G. Influence of trophic conditions on exopolysaccharide production: bacterial biofilm susceptibility to chlorine and monochloramine. Can J Microbiol 1997; 43:751-8. [PMID: 9304786 DOI: 10.1139/m97-108] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study examines the controversial efficacy of chlorine and monochloramine against biofilms that differ in their extracellular polysaccharide (EPS) content. The results point out a net variability of bacterial biofilm susceptibility according to the nutrients present. Chlorine and monochloramine showed an equal biocidal activity on lactose medium-grown E. coli ATCC 10536 and glycerol-ammonium nitrate medium-grown nonmucoid Pseudomonas aeruginosa biofilms. In contrast, the effect of monochloramine is greater compared with that of chlorine on E. coli and mucoid P. aeruginosa biofilms grown in sucrose and glycerol-ammonium nitrate media, respectively. In these culture conditions, treatment with 25 mg monochloramine/L for 2 h reduced culturable cells by 4.5 logs (99.997%) for E. coli and about 3 logs (99.87%) for mucoid P. aeruginosa while the similar treatment with chlorine reduced culturable cells in these biofilms by 2.2 logs (99.4%) and 1 log (10%), respectively. The decrease of chlorine disinfection efficacy on sucrose and glycerol-ammonium nitrate medium-grown biofilms is postulated to be linked to the higher polysaccharide production observed in these media. It seems likely that monochloramine produces a high leakage of material absorbing at 260 nm from sucrose medium-grown E. coli biofilm, which could indicate its better penetration into biofilms.
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Affiliation(s)
- M M Samrakandi
- Laboratoire de bactériologie, virologie et microbiologie industrielle, Faculté des sciences pharmaceutiques, Toulouse, France.
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