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Pontet NGM, Fernández C, Botté SE. Novel method of removing metals from estuarine water using whole microbial mats. Biometals 2024:10.1007/s10534-023-00578-7. [PMID: 38270738 DOI: 10.1007/s10534-023-00578-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024]
Abstract
This study addresses the limited understanding of chromium-microbial mat interactions in estuarine tidal flats. The aims were to evaluate (1) the efficiency of the microbial consortium in Cr(III) removal from seawater; (2) the elemental and mineralogical composition of the microbial mat as a natural system in the Cr removal, (3) the effects of metal on microphytobenthos, and (4) possible interactions of Cr with other metals present in the consortium. Microbial mats were exposed to Cr(III) solutions at different concentrations (2-30 mg Cr/L). Analysis such as metal concentration, organic matter content, chlorophyll a and phaeopigment concentrations, abundance of diatoms and cyanobacteria, SEM-EDS, and XRD were performed. Most of the Cr(III) was deposited, as chromium oxide/hydroxide, on the surface of all microbial mat components. The complete microbial mat, comprising sediments, detritus, EPS, and diverse microorganism communities, exhibited a remarkable capacity to accumulate Cr(III), retaining over 87% in the solution.
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Affiliation(s)
- Natalia Gabriela Morales Pontet
- Argentine Institute of Oceanography, CONICET - National University of the South (UNS), Carrindanga 7.5 km Road, B8000FWB , Bahía Blanca, Argentina.
- Department of Biology, Biochemistry, and Pharmacy, National University of the South (UNS), San Juan 670, B8000ICN, Bahía Blanca, Argentina.
| | - Carolina Fernández
- Institute of Biochemical Research of Bahía Blanca, CONICET - National University of the South (UNS), Carrindanga 7.5 km Road, B8000FWB, Bahía Blanca, Argentina
- Center for Entrepreneurship and Sustainable Territorial Development (CEDETS), Provincial University of the Southwest (UPSO) - Commission of Scientific Research of the Province of Buenos Aires (CIC), Cali 320 city, B8003FTH, Bahía Blanca, Argentina
| | - Sandra Elizabeth Botté
- Argentine Institute of Oceanography, CONICET - National University of the South (UNS), Carrindanga 7.5 km Road, B8000FWB , Bahía Blanca, Argentina
- Department of Biology, Biochemistry, and Pharmacy, National University of the South (UNS), San Juan 670, B8000ICN, Bahía Blanca, Argentina
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2
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Guardia AE, Wagner A, Busalmen JP, Di Capua C, Cortéz N, Beligni MV. The draft genome of Andean Rhodopseudomonas sp. strain AZUL predicts genome plasticity and adaptation to chemical homeostasis. BMC Microbiol 2022; 22:297. [PMID: 36494611 PMCID: PMC9733117 DOI: 10.1186/s12866-022-02685-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/29/2022] [Indexed: 12/13/2022] Open
Abstract
The genus Rhodopseudomonas comprises purple non-sulfur bacteria with extremely versatile metabolisms. Characterization of several strains revealed that each is a distinct ecotype highly adapted to its specific micro-habitat. Here we present the sequencing, genomic comparison and functional annotation of AZUL, a Rhodopseudomonas strain isolated from a high altitude Andean lagoon dominated by extreme conditions and fluctuating levels of chemicals. Average nucleotide identity (ANI) analysis of 39 strains of this genus showed that the genome of AZUL is 96.2% identical to that of strain AAP120, which suggests that they belong to the same species. ANI values also show clear separation at the species level with the rest of the strains, being more closely related to R. palustris. Pangenomic analyses revealed that the genus Rhodopseudomonas has an open pangenome and that its core genome represents roughly 5 to 12% of the total gene repertoire of the genus. Functional annotation showed that AZUL has genes that participate in conferring genome plasticity and that, in addition to sharing the basal metabolic complexity of the genus, it is also specialized in metal and multidrug resistance and in responding to nutrient limitation. Our results also indicate that AZUL might have evolved to use some of the mechanisms involved in resistance as redox reactions for bioenergetic purposes. Most of those features are shared with strain AAP120, and mainly involve the presence of additional orthologs responsible for the mentioned processes. Altogether, our results suggest that AZUL, one of the few bacteria from its habitat with a sequenced genome, is highly adapted to the extreme and changing conditions that constitute its niche.
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Affiliation(s)
- Aisha E. Guardia
- grid.473319.b0000 0004 0461 9871Ingeniería de Interfases y Bioprocesos, Instituto de Tecnología de Materiales (INTEMA-CONICET-UNMdP), Mar del Plata, Argentina
| | - Agustín Wagner
- grid.10814.3c0000 0001 2097 3211Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Juan P. Busalmen
- grid.473319.b0000 0004 0461 9871Ingeniería de Interfases y Bioprocesos, Instituto de Tecnología de Materiales (INTEMA-CONICET-UNMdP), Mar del Plata, Argentina
| | - Cecilia Di Capua
- grid.501777.30000 0004 0638 1836Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR), Universidad Nacional de Rosario, Rosario, Argentina
| | - Néstor Cortéz
- grid.501777.30000 0004 0638 1836Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR), Universidad Nacional de Rosario, Rosario, Argentina
| | - María V. Beligni
- grid.412221.60000 0000 9969 0902Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
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Mohsin H, Asif A, Rehman Y. Anoxic growth optimization for metal respiration and photobiological hydrogen production by arsenic-resistant Rhodopseudomonas and Rhodobacter species. J Basic Microbiol 2019; 59:1208-1216. [PMID: 31613006 DOI: 10.1002/jobm.201900100] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/26/2019] [Accepted: 09/20/2019] [Indexed: 11/09/2022]
Abstract
The current research focuses on anaerobic respiration of arsenic and other toxic metals by purple nonsulfur bacteria (PNSB). Among the optimization assays performed were carbon utilization, cross metal resistance, and metal respiration, along with a comparison of each assay in photoheterotrophic and chemoheterotrophic growth. The bacteria were identified by the classification of 16S ribosomal RNA gene sequences. Rhodobacter sp. PI3 proved to be more versatile in carbon source utilization (acetate, lactate, citrate, and oxalate), whereas Rhodopseudomonas palustris PI5 proved to be more versatile in metal resistance (arsenate, arsenite, cobalt, lead, selenium, and nickel). Both the strains were found to be positive for photofermentative hydrogen production along with arsenic respiration. This study reveals that anaerobic conditions are more appropriate for better efficiency of PNSB. Our study demonstrates that R. palustris PI5 and Rhodobacter sp. PI3 can be promising candidates for the biohydrogen production along with metal detoxification using heavy metal-polluted effluents as a substrate.
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Affiliation(s)
- Hareem Mohsin
- Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan
| | - Azka Asif
- Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan
| | - Yasir Rehman
- Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan.,Department of Life Sciences, School of Science, University of Management and Technology, Lahore, Pakistan
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Luo XW, Zhang DY, Zhu TH, Zhou XG, Peng J, Zhang SB, Liu Y. Adaptation mechanism and tolerance of Rhodopseudomonas palustris PSB-S under pyrazosulfuron-ethyl stress. BMC Microbiol 2018; 18:207. [PMID: 30526497 PMCID: PMC6286529 DOI: 10.1186/s12866-018-1361-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 11/29/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pyrazosulfuron-ethyl is a long lasting herbicide in the agro-ecosystem and its residue is toxic to crops and other non-target organisms. A better understanding of molecular basis in pyrazosulfuron-ethyl tolerant organisms will shed light on the adaptive mechanisms to this herbicide. RESULTS Pyrazosulfuron-ethyl inhibited biomass production in Rhodopseudomonas palustris PSB-S, altered cell morphology, suppressed flagella formation, and reduced pigment biosynthesis through significant suppression of carotenoids biosynthesis. A total of 1127 protein spots were detected in the two-dimensional gel electrophoresis. Among them, 72 spots representing 56 different proteins were found to be differently expressed using MALDI-TOF/TOF-MS, including 26 up- and 30 down-regulated proteins in the pyrazosulfuron-ethyl-treated PSB-S cells. The up-regulated proteins were involved predominantly in oxidative stress or energy generation pathways, while most of the down-regulated proteins were involved in the biomass biosynthesis pathway. The protein expression profiles suggested that the elongation factor G, cell division protein FtsZ, and proteins associated with the ABC transporters were crucial for R. palustris PSB-S tolerance against pyrazosulfuron-ethyl. CONCLUSION Up-regulated proteins, including elongation factor G, cell division FtsZ, ATP synthase, and superoxide dismutase, and down-regulated proteins, including ALS III and ABC transporters, as well as some unknown proteins might play roles in R. palustris PSB-S adaptation to pyrazosulfuron-ethyl induced stresses. Functional validations of these candidate proteins should help to develope transgenic crops resistant to pyrazosulfuron-ethyl.
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Affiliation(s)
- Xiang-Wen Luo
- Key laboratory of pest management of horticultural crop of Hunan province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, No 726 Second Yuanda Road, Furong District, Changsha, 410125, Hunan province, People's Republic of China.,Plant Protection College, Hunan Agricultural University, Changsha, 410128, China
| | - De-Yang Zhang
- Key laboratory of pest management of horticultural crop of Hunan province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, No 726 Second Yuanda Road, Furong District, Changsha, 410125, Hunan province, People's Republic of China.,Plant Protection College, Hunan Agricultural University, Changsha, 410128, China
| | - Teng-Hui Zhu
- Plant Protection College, Hunan Agricultural University, Changsha, 410128, China
| | - Xu-Guo Zhou
- Department of Entomology, University of Kentucky, Lexington, KY, 40546, USA
| | - Jing Peng
- Key laboratory of pest management of horticultural crop of Hunan province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, No 726 Second Yuanda Road, Furong District, Changsha, 410125, Hunan province, People's Republic of China.,Plant Protection College, Hunan Agricultural University, Changsha, 410128, China
| | - Song-Bai Zhang
- Key laboratory of pest management of horticultural crop of Hunan province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, No 726 Second Yuanda Road, Furong District, Changsha, 410125, Hunan province, People's Republic of China.
| | - Yong Liu
- Key laboratory of pest management of horticultural crop of Hunan province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, No 726 Second Yuanda Road, Furong District, Changsha, 410125, Hunan province, People's Republic of China. .,Plant Protection College, Hunan Agricultural University, Changsha, 410128, China.
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Potential of Rhodobacter capsulatus Grown in Anaerobic-Light or Aerobic-Dark Conditions as Bioremediation Agent for Biological Wastewater Treatments. WATER 2017. [DOI: 10.3390/w9020108] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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6
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Venkidusamy K, Megharaj M. A Novel Electrophototrophic Bacterium Rhodopseudomonas palustris Strain RP2, Exhibits Hydrocarbonoclastic Potential in Anaerobic Environments. Front Microbiol 2016; 7:1071. [PMID: 27462307 PMCID: PMC4940424 DOI: 10.3389/fmicb.2016.01071] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/27/2016] [Indexed: 11/13/2022] Open
Abstract
An electrophototrophic, hydrocarbonoclastic bacterium Rhodopseudomonas palustris stain RP2 was isolated from the anodic biofilms of hydrocarbon fed microbial electrochemical remediation systems (MERS). Salient properties of the strain RP2 were direct electrode respiration, dissimilatory metal oxide reduction, spore formation, anaerobic nitrate reduction, free living diazotrophy and the ability to degrade n-alkane components of petroleum hydrocarbons (PH) in anoxic, photic environments. In acetate fed microbial electrochemical cells, a maximum current density of 305 ± 10 mA/m(2) (1000Ω) was generated (power density 131.65 ± 10 mW/m(2)) by strain RP2 with a coulombic efficiency of 46.7 ± 1.3%. Cyclic voltammetry studies showed that anaerobically grown cells of strain RP2 is electrochemically active and likely to transfer electrons extracellularly to solid electron acceptors through membrane bound compounds, however, aerobically grown cells lacked the electrochemical activity. The ability of strain RP2 to produce current (maximum current density 21 ± 3 mA/m(2); power density 720 ± 7 μW/m(2), 1000 Ω) using PH as a sole energy source was also examined using an initial concentration of 800 mg l(-1) of diesel range hydrocarbons (C9-C36) with a concomitant removal of 47.4 ± 2.7% hydrocarbons in MERS. Here, we also report the first study that shows an initial evidence for the existence of a hydrocarbonoclastic behavior in the strain RP2 when grown in different electron accepting and illuminated conditions (anaerobic and MERS degradation). Such observations reveal the importance of photoorganotrophic growth in the utilization of hydrocarbons from contaminated environments. Identification of such novel petrochemical hydrocarbon degrading electricigens, not only expands the knowledge on the range of bacteria known for the hydrocarbon bioremediation but also shows a biotechnological potential that goes well beyond its applications to MERS.
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Affiliation(s)
- Krishnaveni Venkidusamy
- Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SAAustralia; CRC for Contamination Assessment and Remediation of the Environment, Mawson Lakes, SAAustralia
| | - Mallavarapu Megharaj
- Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SAAustralia; CRC for Contamination Assessment and Remediation of the Environment, Mawson Lakes, SAAustralia; Global Centre for Environmental Risk Assessment and Remediation, The University of Newcastle, Callaghan, NSWAustralia
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Katsaveli K, Vayenas D, Tsiamis G, Bourtzis K. Bacterial diversity in Cr(VI) and Cr(III)-contaminated industrial wastewaters. Extremophiles 2012; 16:285-96. [PMID: 22258276 DOI: 10.1007/s00792-012-0429-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 01/05/2012] [Indexed: 11/28/2022]
Abstract
The bacterial community structure of a chromium water bath, a chromium drainage waste system, a chromium pretreatment tank, and a trivalent chromium precipitation tank from the Hellenic Aerospace Industry S.A. was assessed using 16S rRNA libraries and a high-density DNA microarray (PhyloChip). 16S rRNA libraries revealed a bacterial diversity consisting of 14 distinct operational taxonomic units belonging to five bacterial phyla: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Actinobacteria, and Bacteroidetes. However, employing a novel microarray-based approach (PhyloChip), a high bacterial diversity consisting of 30 different phyla was revealed, with representatives of 181 different families. This made it possible to identify a core set of genera present in all wastewater treatment stages examined, consisting of members of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Epsilonproteobacteria, and Bacteroidetes. In the chromium pretreatment tank, where the concentration of Cr(VI) is high (2.3 mg/l), we identified the presence of Pseudomonadales, Actinomycetales, and Enterobacteriales in abundance. In the chromium precipitation tank, where the concentration of Cr(III) is high, the dominant bacteria consortia were replaced by members of Rhodocyclales and Chloroflexi. The bacterial community structure changed significantly with changes in the chromium concentration. This in-depth analysis should prove useful for the design and development of improved bioremediation strategies.
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Affiliation(s)
- Katerina Katsaveli
- Department of Environmental and Natural Resources Management, University of Ioannina, 2 Seferi St., 30100, Agrinio, Greece.
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Simmons SS, Isokpehi RD, Brown SD, McAllister DL, Hall CC, McDuffy WM, Medley TL, Udensi UK, Rajnarayanan RV, Ayensu WK, Cohly HHP. Functional Annotation Analytics of Rhodopseudomonas palustris Genomes. Bioinform Biol Insights 2011; 5:115-29. [PMID: 22084572 PMCID: PMC3201837 DOI: 10.4137/bbi.s7316] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Rhodopseudomonas palustris, a nonsulphur purple photosynthetic bacteria, has been extensively investigated for its metabolic versatility including ability to produce hydrogen gas from sunlight and biomass. The availability of the finished genome sequences of six R. palustris strains (BisA53, BisB18, BisB5, CGA009, HaA2 and TIE-1) combined with online bioinformatics software for integrated analysis presents new opportunities to determine the genomic basis of metabolic versatility and ecological lifestyles of the bacteria species. The purpose of this investigation was to compare the functional annotations available for multiple R. palustris genomes to identify annotations that can be further investigated for strain-specific or uniquely shared phenotypic characteristics. A total of 2,355 protein family Pfam domain annotations were clustered based on presence or absence in the six genomes. The clustering process identified groups of functional annotations including those that could be verified as strain-specific or uniquely shared phenotypes. For example, genes encoding water/glycerol transport were present in the genome sequences of strains CGA009 and BisB5, but absent in strains BisA53, BisB18, HaA2 and TIE-1. Protein structural homology modeling predicted that the two orthologous 240 aa R. palustris aquaporins have water-specific transport function. Based on observations in other microbes, the presence of aquaporin in R. palustris strains may improve freeze tolerance in natural conditions of rapid freezing such as nitrogen fixation at low temperatures where access to liquid water is a limiting factor for nitrogenase activation. In the case of adaptive loss of aquaporin genes, strains may be better adapted to survive in conditions of high-sugar content such as fermentation of biomass for biohydrogen production. Finally, web-based resources were developed to allow for interactive, user-defined selection of the relationship between protein family annotations and the R. palustris genomes.
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Affiliation(s)
- Shaneka S Simmons
- Department of Biology, Center for Bioinformatics & Computational Biology, Department of Biology, Jackson State University, PO Box 18540 Jackson MS 39217 USA
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9
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Scientific Opinion on the maintenance of the list of QPS microorganisms intentionally added to food or feed (2009 update). EFSA J 2009. [DOI: 10.2903/j.efsa.2009.1431] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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10
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Okubo Y, Futamata H, Hiraishi A. Characterization of phototrophic purple nonsulfur bacteria forming colored microbial mats in a swine wastewater ditch. Appl Environ Microbiol 2006; 72:6225-33. [PMID: 16957249 PMCID: PMC1563592 DOI: 10.1128/aem.00796-06] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The community structure of pink-colored microbial mats naturally occurring in a swine wastewater ditch was studied by culture-independent biomarker and molecular methods as well as by conventional cultivation methods. The wastewater in the ditch contained acetate and propionate as the major carbon nutrients. Thin-section electron microscopy revealed that the microbial mats were dominated by rod-shaped cells containing intracytoplasmic membranes of the lamellar type. Smaller numbers of oval cells with vesicular internal membranes were also found. Spectroscopic analyses of the cell extract from the biomats showed the presence of bacteriochlorophyll a and carotenoids of the spirilloxanthin series. Ubiquinone-10 was detected as the major quinone. A clone library of the photosynthetic gene, pufM, constructed from the bulk DNA of the biomats showed that all of the clones were derived from members of the genera Rhodobacter and Rhodopseudomonas. The dominant phototrophic bacteria from the microbial mats were isolated by cultivation methods and identified as being of the genera Rhodobacter and Rhodopseudomonas by studying 16S rRNA and pufM gene sequence information. Experiments of oxygen uptake with lower fatty acids revealed that the freshly collected microbial mats and the Rhodopseudomonas isolates had a wider spectrum of carbon utilization and a higher affinity for acetate than did the Rhodobacter isolates. These results demonstrate that the microbial mats were dominated by the purple nonsulfur bacteria of the genera Rhodobacter and Rhodopseudomonas, and the bioavailability of lower fatty acids in wastewater is a key factor allowing the formation of visible microbial mats with these phototrophs.
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Affiliation(s)
- Yoko Okubo
- Ecological Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan
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Jiao Y, Kappler A, Croal LR, Newman DK. Isolation and characterization of a genetically tractable photoautotrophic Fe(II)-oxidizing bacterium, Rhodopseudomonas palustris strain TIE-1. Appl Environ Microbiol 2005; 71:4487-96. [PMID: 16085840 PMCID: PMC1183355 DOI: 10.1128/aem.71.8.4487-4496.2005] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Accepted: 03/11/2005] [Indexed: 11/20/2022] Open
Abstract
We report the isolation and characterization of a phototrophic ferrous iron [Fe(II)]-oxidizing bacterium named TIE-1 that differs from other Fe(II)-oxidizing phototrophs in that it is genetically tractable. Under anaerobic conditions, TIE-1 grows photoautotrophically with Fe(II), H2, or thiosulfate as the electron donor and photoheterotrophically with a variety of organic carbon sources. TIE-1 also grows chemoheterotrophically in the dark. This isolate appears to be a new strain of the purple nonsulfur bacterial species Rhodopseudomonas palustris, based on physiological and phylogenetic analysis. Fe(II) oxidation is optimal at pH 6.5 to 6.9. The mineral products of Fe(II) oxidation are pH dependent: below pH 7.0 goethite (alpha-FeOOH) forms, and above pH 7.2 magnetite (Fe3O4) forms. TIE-1 forms colonies on agar plates and is sensitive to a variety of antibiotics. A hyperactive mariner transposon is capable of random insertion into the chromosome with a transposition frequency of approximately 10(-5). To identify components involved in phototrophic Fe(II) oxidation, mutants of TIE-1 were generated by transposon mutagenesis and screened for defects in Fe(II) oxidation in a cell suspension assay. Among approximately 12,000 mutants screened, 6 were identified that are specifically impaired in Fe(II) oxidation. Five of these mutants have independent disruptions in a gene that is predicted to encode an integral membrane protein that appears to be part of an ABC transport system; the sixth mutant has an insertion in a gene that is a homolog of CobS, an enzyme involved in cobalamin (vitamin B12) biosynthesis.
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Affiliation(s)
- Yongqin Jiao
- California Institute of Technology, Division of Geological and Planetary Sciences, Mail Stop 100-23, Pasadena, CA 91125, USA
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12
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Sheng GP, Yu HQ, Yu Z. Extraction of extracellular polymeric substances from the photosynthetic bacterium Rhodopseudomonas acidophila. Appl Microbiol Biotechnol 2004; 67:125-30. [PMID: 15309338 DOI: 10.1007/s00253-004-1704-5] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2004] [Revised: 06/20/2004] [Accepted: 06/25/2004] [Indexed: 10/26/2022]
Abstract
Among the four methods for extracting extracellular polymeric substances (EPS) from Rhodopseudomonas acidophila (EDTA, NaOH, H(2)SO(4), heating/centrifugation), EDTA extraction was found to be the most effective. The contents of the major components of EPS from R. acidophila, i.e., carbohydrate, protein and nucleic acid, were 6.5, 58.4 and 5.4 mg g(-1) dry cells, respectively. The optimum extraction time was 1-3 h and the EDTA dosage was approximately 2.8 g g(-1) dry cells. Under these conditions, no cell lysis was observed. The EPS content and the percentage of the three main components were greatly dependent on the extraction method. The intensity of absorption peaks for photosynthetic pigments in the UV-visible spectrum of bacteria remained unchanged prior to and after EDTA extraction; and no pigment peaks appeared in the EPS spectrum. This suggests that few cells were destroyed and lysis did not occur. UV-visible spectrum analysis, an easy and rapid technique, could be used to monitor cell lysis during EPS extraction from R. acidophila.
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Affiliation(s)
- Guo-Ping Sheng
- Department of Chemistry, Laboratory of Environmental Biotechnology, University of Science and Technology of China, Hefei, Anhui 230026, China
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Kretschmer XC, Meitzner G, Gardea-Torresdey JL, Webb R. Determination of Cu environments in the cyanobacterium Anabaena flos-aquae by X-ray absorption spectroscopy. Appl Environ Microbiol 2004; 70:771-80. [PMID: 14766554 PMCID: PMC348884 DOI: 10.1128/aem.70.2.771-780.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Whole cells and peptidoglycan isolated from cell walls of the cyanobacterium Anabaena flos-aquae were lyophilized and used at pH 2 and pH 5 in Cu(II) binding studies. X-ray absorption spectra measured at the Cu K-edge were used to determine the oxidation states and chemical environments of Cu species in the whole-cell and peptidoglycan samples. In the whole-cell samples, most of the Cu retained at both pH values was coordinated by phosphate ligands. The whole-cell fractions contained significant concentrations of Cu(I) as well as Cu(II). An X-ray absorption near-edge spectrum analysis suggested that Cu(I) was coordinated by amine and thiol ligands. An analysis of the peptidoglycan fractions found that more Cu was adsorbed by the peptidoglycan fraction prepared at pH 5, due to increased chelation by amine and carboxyl ligands. The peptidoglycan fractions, also referred to as the cell wall fractions, contained little or no Cu(I). The Cu loading level was 30 times higher in the cell wall sample prepared at pH 5 than in the sample prepared at pH 2. Amine and bidentate carboxyl ligands had similar relative levels of importance in cell wall peptidoglycan samples prepared at both pH values, but phosphate coordination was insignificant.
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Affiliation(s)
- X C Kretschmer
- Department of Environmental Science and Engineering, The University of Texas at El Paso, El Paso, Texas 79968, USA.
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14
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Determination of copper binding in Anabaena flos-aquae purified cell walls and whole cells by X-ray absorption spectroscopy. Microchem J 2002. [DOI: 10.1016/s0026-265x(02)00022-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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