| enzymatic iron oxidation by leptothrix discophora: identification of an iron-oxidizing protein. | an iron-oxidizing factor was identified in the spent culture medium of the iron- and manganese-oxidizing bacterial strain leptothrix discophora ss-1. it appeared to be a protein, with an apparent molecular weight of approximately 150,000. its activity could be demonstrated after fractionation of the spent medium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. a spontaneous mutant of l. discophora ss-1 was isolated which excreted neither manganese- nor iron-oxidizing activity, where ... | 1992 | 1610168 |
| freeze-substitution of gram-negative eubacteria: general cell morphology and envelope profiles. | freeze-substitution was performed on strains of escherichia coli, pasteurella multocida, campylobacter fetus, vibrio cholerae, pseudomonas aeruginosa, pseudomonas putida, aeromonas salmonicida, proteus mirabilis, haemophilus pleuropneumoniae, caulobacter crescentus, and leptothrix discophora with a substitution medium composed of 2% osmium tetroxide and 2% uranyl acetate in anhydrous acetone. a thick periplasmic gel ranging from 10.6 to 14.3 nm in width was displayed in e. coli k-12, k30, and hi ... | 1991 | 1999383 |
| manganese oxidation by leptothrix discophora. | cells of leptothrix discophora ss1 released mn2+-oxidizing factors into the medium during growth in batch culture. manganese was optimally oxidized when the medium was buffered with hepes (n-2-hydroxyethylpiperazine-n'-2-ethanesulfonic acid) at ph 7.5. manganese-oxidizing activity in the culture medium in which this strain had been grown previously was sensitive to heat, phosphate, tris, nan3, hgcl2 nacl, sodium dodecyl sulfate, and pronase; 0.5 mol of o2 was consumed per mol of mno2 formed. dur ... | 1987 | 3804969 |
| characterization of extracellular mn2+-oxidizing activity and isolation of an mn2+-oxidizing protein from leptothrix discophora ss-1. | supernatant fluid from leptothrix discophora ss-1 cultures possessed high mn2+-ozidizing activity. studies of temperature and ph optima, chemical inhibition, and protease sensitivity suggested that the activity may be enzymatic. kinetic studies of unconcentrated supernatant fluid indicated an apparent km of 7 microm mn2+ in the 1 to 200 microm mn2+ range. the greatest vmax value observed was 1.4 nmol of mn2+ oxidized min-1 micrograms of protein-1 in unconcentrated samples. when the supernatant f ... | 1987 | 3818545 |
| ultrastructure and chemical composition of the sheath of leptothrix discophora sp-6. | light microscopy and transmission electron microscopy of thin sections and metal-shadowed specimens showed that the sheath of leptothrix discophora sp-6 (atcc 51168) is a tube-like extracellular polymeric structure consisting of a condensed fabric of 6.5-nm-diameter fibrils underlying a more diffuse outer capsular layer. in thin sections, outer membrane bridges seen to contact the inner sheath layer suggested that the sheath fabric was attached to the outer layer of the gram-negative cell wall. ... | 1993 | 7504663 |
| role of disulfide bonds in maintaining the structural integrity of the sheath of leptothrix discophora sp-6. | isolated sheaths of leptothrix discophora sp-6 (atcc 51168) were tested for susceptibility to degradation by a variety of chemical denaturants and lytic enzymes and found to be resistant to many reagents and enzyme treatments. however, disulfide bond-reducing agents such as dithiothreitol (dtt), beta-mercaptoethanol, sodium cyanide, and sodium sulfite degraded the sheath, especially at elevated ph (ph 9) and temperature (50 degrees c). dtt and beta-mercaptoethanol caused more rapid degradation o ... | 1993 | 8253670 |
| development and application of 16s rrna-targeted probes for detection of iron- and manganese-oxidizing sheathed bacteria in environmental samples. | comparative sequence analysis of the 16s rrna genes from several leptothrix and sphaerotilus strains led to the design of an oligonucleotide probe (ps-1) based on a sequence within the hypervariable region 1 specific for four leptothrix strains and for one of the four sphaerotilus natans strains examined. another probe (psp-6) was based on a sequence within the hypervariable region 2. psp-6 was specific for one of the two evolutionary lineages previously described for leptothrix spp. (p. l. sier ... | 1997 | 9023942 |
| bacterial community dynamics during start-up of a trickle-bed bioreactor degrading aromatic compounds. | this study was performed with a laboratory-scale fixed-bed bioreactor degrading a mixture of aromatic compounds (solvesso100). the starter culture for the bioreactor was prepared in a fermentor with a wastewater sample of a care painting facility as the inoculum and solvesso100 as the sole carbon source. the bacterial community dynamics in the fermentor and the bioreactor were examined by a conventional isolation procedure and in situ hybridization with fluorescently labeled rrna-targeted oligon ... | 1998 | 9501433 |
| ecophysiological and phylogenetic studies of nevskia ramosa in pure culture. | during the last 100 years, the neuston bacterium nevskia ramosa has been described several times. this bacterium forms conspicuous rosette-like microcolonies at the air-water interface. in this study, pure cultures of nevskia ramosa were obtained for the first time, from a bog lake (strain soe1, dsmz 11499t) and a freshwater ditch (strain ol1, dsmz 11500). the isolates showed special adaptations to life in the epineuston. they formed hydrophobic surface films with a dull appearance. n. ramosa is ... | 1998 | 9572968 |
| structural and biochemical analysis of the sheath of phormidium uncinatum. | the sheath of the filamentous, gliding cyanobacterium phormidium uncinatum was studied by using light and electron microscopy. in thin sections and freeze fractures the sheath was found to be composed of helically arranged carbohydrate fibrils, 4 to 7 nm in diameter, which showed a substantial degree of crystallinity. as in all other examined motile cyanobacteria, the arrangement of the sheath fibrils correlates with the motion of the filaments during gliding motility; i.e., the fibrils formed a ... | 1998 | 9683490 |
| c-type cytochromes and manganese oxidation in pseudomonas putida mnb1. | pseudomonas putida mnb1 is an isolate from an mn oxide-encrusted pipeline that can oxidize mn(ii) to mn oxides. we used transposon mutagenesis to construct mutants of strain mnb1 that are unable to oxidize manganese, and we characterized some of these mutants. the mutants were divided into three groups: mutants defective in the biogenesis of c-type cytochromes, mutants defective in genes that encode key enzymes of the tricarboxylic acid cycle, and mutants defective in the biosynthesis of tryptop ... | 1998 | 9758766 |
| the cytochrome c maturation operon is involved in manganese oxidation in pseudomonas putida gb-1. | a pseudomonas putida strain, strain gb-1, oxidizes mn2+ to mn oxide in the early stationary growth phase. it also secretes a siderophore (identified as pyoverdine) when it is subjected to iron limitation. after transposon (tn5) mutagenesis several classes of mutants with differences in mn2+ oxidation and/or secretion of the mn2+-oxidizing activity were identified. preliminary analysis of the tn5 insertion site in one of the nonoxidizing mutants suggested that a multicopper oxidase-related enzyme ... | 1998 | 9758767 |
| morphological and biochemical properties of a sphaerotilus sp. isolated from paper mill slimes. | four strains of filamentous bacteria were isolated from slimes collected in different paper mill factories. morphological and physiological characterization of the isolates indicated an affiliation with the genus sphaerotilus. however, while the physiological properties of the isolates were almost identical, pronounced physiological differences between the isolates and sphaerotilus natans dsm 6575(t), dsm 565, and dsm 566 with respect to their ability to metabolize complex polysaccharides, sugar ... | 1999 | 9872774 |
| production of biogenic mn oxides by leptothrix discophora ss-1 in a chemically defined growth medium and evaluation of their pb adsorption characteristics | biogenic mn oxides were produced by the bacterium leptothrix discophora ss-1 (= atcc 3182) in a chemically defined mineral salts medium, and the pb binding and specific surface area of these oxides were characterized. growth of ss-1 in the defined medium with pyruvate as a carbon and energy source required the addition of vitamin b12. complete oxidation of mn(ii) within 60 h required the addition of >/=0.1 &mgr;m feso4. pb adsorption isotherms were determined for the biogenic mn oxides (and asso ... | 1999 | 9872777 |
| cuma, a gene encoding a multicopper oxidase, is involved in mn2+ oxidation in pseudomonas putida gb-1. | pseudomonas putida gb-1-002 catalyzes the oxidation of mn2+. nucleotide sequence analysis of the transposon insertion site of a nonoxidizing mutant revealed a gene (designated cuma) encoding a protein homologous to multicopper oxidases. addition of cu2+ increased the mn2+-oxidizing activity of the p. putida wild type by a factor of approximately 5. the growth rates of the wild type and the mutant were not affected by added cu2+. a second open reading frame (designated cumb) is located downstream ... | 1999 | 10103278 |
| phylogenetic analysis of ara+ and ara- burkholderia pseudomallei isolates and development of a multiplex pcr procedure for rapid discrimination between the two biotypes. | a burkholderia pseudomallei-like organism has recently been identified among some soil isolates of b. pseudomallei in an area with endemic melioidosis. this organism is almost identical to b. pseudomallei in terms of morphological and biochemical profiles, except that it differs in ability to assimilate l-arabinose. these ara+ isolates are also less virulent than the ara- isolates in animal models. in addition, clinical isolates of b. pseudomallei available to date are almost exclusively ara-. t ... | 1999 | 10325345 |
| novel bacterial and archaeal lineages from an in situ growth chamber deployed at a mid-atlantic ridge hydrothermal vent. | the phylogenetic diversity was determined for a microbial community obtained from an in situ growth chamber placed on a deep-sea hydrothermal vent on the mid-atlantic ridge (23 degrees 22' n, 44 degrees 57' w). the chamber was deployed for 5 days, and the temperature within the chamber gradually decreased from 70 to 20 degrees c. upon retrieval of the chamber, the dna was extracted and the small-subunit rrna genes (16s rdna) were amplified by pcr using primers specific for the archaea or bacteri ... | 2000 | 10966393 |
| purification and properties of an enzyme capable of degrading the sheath of sphaerotilus natans. | microorganisms which can degrade and grow on the purified sheath of a sheathed bacterium sphaerotilus natans were collected from soil and river water. two bacterial strains were isolated from the soil and designated strains tb and tk. both strains are rod shaped, negatively stained by gram staining, facultatively anaerobic, and formed ellipsoidal endospores. these characteristics suggested that the isolates belong to the genus paenibacillus, according to ash et al. (c. ash, f. g. priest, and m. ... | 2000 | 11055955 |
| cota of bacillus subtilis is a copper-dependent laccase. | the spore coat protein cota of bacillus subtilis displays similarities with multicopper oxidases, including manganese oxidases and laccases. b. subtilis is able to oxidize manganese, but neither cota nor other sporulation proteins are involved. we demonstrate that cota is a laccase. syringaldazine, a specific substrate of laccases, reacted with wild-type spores but not with deltacota spores. cota may participate in the biosynthesis of the brown spore pigment, which appears to be a melanin-like p ... | 2001 | 11514528 |
| enzymatic manganese(ii) oxidation by a marine alpha-proteobacterium. | a yellow-pigmented marine bacterium, designated strain sd-21, was isolated from surface sediments of san diego bay, san diego, calif., based on its ability to oxidize soluble mn(ii) to insoluble mn(iii, iv) oxides. 16s rrna analysis revealed that this organism was most closely related to members of the genus erythrobacter, aerobic anoxygenic phototrophic bacteria within the alpha-4 subgroup of the proteobacteria (alpha-4 proteobacteria). sd-21, however, has a number of distinguishing phenotypic ... | 2001 | 11526000 |
| cuma multicopper oxidase genes from diverse mn(ii)-oxidizing and non-mn(ii)-oxidizing pseudomonas strains. | a multicopper oxidase gene, cuma, required for mn(ii) oxidation was recently identified in pseudomonas putida strain gb-1. in the present study, degenerate primers based on the putative copper-binding regions of the cuma gene product were used to pcr amplify cuma gene sequences from a variety of pseudomonas strains, including both mn(ii)-oxidizing and non-mn(ii)-oxidizing strains. the presence of highly conserved cuma gene sequences in several apparently non-mn(ii)-oxidizing pseudomonas strains ... | 2001 | 11526033 |
| identification of a gene essential for sheathed structure formation in sphaerotilus natans, a filamentous sheathed bacterium. | sphaerotilus natans, a filamentous bacterium that causes bulking in activated sludge processes, can assume two distinct morphologies, depending on the substrate concentration for growth; in substrate-rich media it grows as single rod-shaped cells, whereas in substrate-limited media it grows as filaments. to identify genes responsible for sheath formation, we carried out transposon tn5 mutagenesis. of the approximately 20,000 mutants obtained, 7 did not form sheathed structures. sequencing of the ... | 2002 | 11772646 |
| enzymatic manganese(ii) oxidation by metabolically dormant spores of diverse bacillus species. | bacterial spores are renowned for their longevity, ubiquity, and resistance to environmental insults, but virtually nothing is known regarding whether these metabolically dormant structures impact their surrounding chemical environments. in the present study, a number of spore-forming bacteria that produce dormant spores which enzymatically oxidize soluble mn(ii) to insoluble mn(iv) oxides were isolated from coastal marine sediments. the highly charged and reactive surfaces of biogenic metal oxi ... | 2002 | 11823231 |
| differences in hyporheic-zone microbial community structure along a heavy-metal contamination gradient. | the hyporheic zone of a river is nonphotic, has steep chemical and redox gradients, and has a heterotrophic food web based on the consumption of organic carbon entrained from downwelling surface water or from upwelling groundwater. the microbial communities in the hyporheic zone are an important component of these heterotrophic food webs and perform essential functions in lotic ecosystems. using a suite of methods (denaturing gradient gel electrophoresis, 16s rrna phylogeny, phospholipid fatty a ... | 2003 | 12957946 |
| quantitative molecular assay for fingerprinting microbial communities of wastewater and estrogen-degrading consortia. | a quantitative fingerprinting method, called the real-time terminal restriction fragment length polymorphism (real-time-t-rflp) assay, was developed for simultaneous determination of microbial diversity and abundance within a complex community. the real-time-t-rflp assay was developed by incorporating the quantitative feature of real-time pcr and the fingerprinting feature of t-rflp analysis. the assay was validated by using a model microbial community containing three pure strains, an escherich ... | 2005 | 15746346 |
| evidence for the presence of mn(iii) intermediates in the bacterial oxidation of mn(ii). | bacterial oxidation of mn(ii) to mn(iv) is believed to drive the oxidative segment of the global biogeochemical mn cycle and regulates the concentration of dissolved mn(ii) in the oceanic water column, where it is a critical nutrient for planktonic primary productivity. mn(ii) oxidizing activity is expressed by numerous phylogenetically diverse bacteria and fungi, suggesting that it plays a fundamental and ubiquitous role in the environment. this important redox system is believed to be driven b ... | 2005 | 15800042 |
| novel approach to quantitative detection of specific rrna in a microbial community, using catalytic dna. | we developed a novel method for the quantitative detection of the 16s rrna of a specific bacterial species in the microbial community by using deoxyribozyme (dnazyme), which possesses the catalytic function to cleave rna in a sequence-specific manner. a mixture of heterogeneous 16s rrna containing the target 16s rrna was incubated with a species-specific dnazyme. the cleaved target 16s rrna was separated from the intact 16s rrna by electrophoresis, and then their amounts were compared for the qu ... | 2005 | 16085888 |
| new chitosan-degrading strains that produce chitosanases similar to choa of mitsuaria chitosanitabida. | the betaproteobacterium mitsuaria chitosanitabida (formerly matsuebacter chitosanotabidus) 3001 produces a chitosanase (choa) that is classified in glycosyl hydrolase family 80. while many chitosanase genes have been isolated from various bacteria to date, they show limited homology to the m. chitosanitabida 3001 chitosanase gene (choa). to investigate the phylogenetic distribution of chitosanases analogous to choa in nature, we identified 67 chitosan-degrading strains by screening and investiga ... | 2005 | 16151097 |
| influence of manganese on growth of a sheathless strain of leptothrix discophora. | mn exerted various effects on the growth of leptothrix discophora strain ss-1 in batch cultures depending on the concentration added to the medium. concentrations of 0.55 to 5.5 mum mn, comparable to those in the environment from which strain ss-1 was isolated, decreased cell yield and prolonged stationary-phase survival, but did not affect growth rate. elevated concentrations of 55 to 910 mum mn also decreased cell yield and prolonged survival, but growth rate was decreased as well. the additio ... | 1985 | 16346750 |
| oxidation of manganese and iron by leptothrix discophora: use of n,n,n',n'-tetramethyl-p-phenylenediamine as an indicator of metal oxidation. | a new method for the quantification and characterization of manganese-oxidizing activity by spent culture medium of leptothrix discophora ss-1 was developed. it is based on the formation of the dye wurster blue from n,n,n',n'-tetramethyl-p-phenylenediamine by oxidized manganese generated in the spent medium. the kinetic parameters thus obtained agreed well with data obtained with other methods. it was also possible to demonstrate iron oxidation by spent culture medium. the kinetics of the proces ... | 1990 | 16348351 |
| isolation, cultural maintenance, and taxonomy of a sheath-forming strain of leptothrix discophora and characterization of manganese-oxidizing activity associated with the sheath. | leptothrix discophora sp-6 was isolated from the outflow reservoir of an artificial iron seep. its sheathforming phenotype was maintained by slow growth in a mineral salts-vitamin-pyruvate medium under minimal aeration at 20 to 25 degrees c. a sheathless variant, sp-6(sl), was isolated from smooth colonies that appeared on spread plates after rapid growth of sp-6 in well-aerated cultures. sp-6 and sp-6(sl) are closely related but not identical to the previously studied sheathless strain ss-1 (at ... | 1992 | 16348826 |
| ennoblement of stainless steel by the manganese-depositing bacterium leptothrix discophora. | the noble shift in open-circuit potential exhibited by microbially colonized stainless steel (ennoblement) was investigated by examining the relationship among surface colonization, manganese deposition, and open-circuit potential for stainless steel coupons exposed to batch cultures of the manganese-depositing bacterium leptothrix discophora. open-circuit potential shifted from -100 to +330 mv(infsce) as a biofilm containing 75 nmol of mno(infx) cm(sup-2) formed on the coupon surface but change ... | 1997 | 16535635 |
| coupled photochemical and enzymatic mn(ii) oxidation pathways of a planktonic roseobacter-like bacterium. | bacteria belonging to the roseobacter clade of the alpha-proteobacteria occupy a wide range of environmental niches and are numerically abundant in coastal waters. here we reveal that roseobacter-like bacteria may play a previously unrecognized role in the oxidation and cycling of manganese (mn) in coastal waters. a diverse array of mn(ii)-oxidizing roseobacter-like species were isolated from elkhorn slough, a coastal estuary adjacent to monterey bay in california. one isolate (designated azwk-3 ... | 2006 | 16672501 |
| a novel lineage of proteobacteria involved in formation of marine fe-oxidizing microbial mat communities. | for decades it has been recognized that neutrophilic fe-oxidizing bacteria (feob) are associated with hydrothermal venting of fe(ii)-rich fluids associated with seamounts in the world's oceans. the evidence was based almost entirely on the mineralogical remains of the microbes, which themselves had neither been brought into culture or been assigned to a specific phylogenetic clade. we have used both cultivation and cultivation-independent techniques to study fe-rich microbial mats associated wit ... | 2007 | 17668050 |
| in vitro studies indicate a quinone is involved in bacterial mn(ii) oxidation. | manganese(ii)-oxidizing bacteria play an integral role in the cycling of mn as well as other metals and organics. prior work with mn(ii)-oxidizing bacteria suggested that mn(ii) oxidation involves a multicopper oxidase, but whether this enzyme directly catalyzes mn(ii) oxidation is unknown. for a clearer understanding of mn(ii) oxidation, we have undertaken biochemical studies in the model marine alpha-proteobacterium, erythrobacter sp. strain sd21. the optimum ph for mn(ii)-oxidizing activity w ... | 2008 | 17673976 |
| in vitro studies indicate a quinone is involved in bacterial mn(ii) oxidation. | manganese(ii)-oxidizing bacteria play an integral role in the cycling of mn as well as other metals and organics. prior work with mn(ii)-oxidizing bacteria suggested that mn(ii) oxidation involves a multicopper oxidase, but whether this enzyme directly catalyzes mn(ii) oxidation is unknown. for a clearer understanding of mn(ii) oxidation, we have undertaken biochemical studies in the model marine alpha-proteobacterium, erythrobacter sp. strain sd21. the optimum ph for mn(ii)-oxidizing activity w ... | 2008 | 17673976 |
| direct identification of a bacterial manganese(ii) oxidase, the multicopper oxidase mnxg, from spores of several different marine bacillus species. | microorganisms catalyze the formation of naturally occurring mn oxides, but little is known about the biochemical mechanisms of this important biogeochemical process. we used tandem mass spectrometry to directly analyze the mn(ii)-oxidizing enzyme from marine bacillus spores, identified as an mn oxide band with an in-gel activity assay. nine distinct peptides recovered from the mn oxide band of two bacillus species were unique to the multicopper oxidase mnxg, and one peptide was from the small h ... | 2008 | 18165363 |
| direct identification of a bacterial manganese(ii) oxidase, the multicopper oxidase mnxg, from spores of several different marine bacillus species. | microorganisms catalyze the formation of naturally occurring mn oxides, but little is known about the biochemical mechanisms of this important biogeochemical process. we used tandem mass spectrometry to directly analyze the mn(ii)-oxidizing enzyme from marine bacillus spores, identified as an mn oxide band with an in-gel activity assay. nine distinct peptides recovered from the mn oxide band of two bacillus species were unique to the multicopper oxidase mnxg, and one peptide was from the small h ... | 2008 | 18165363 |
| phylogenetic relationships and functional genes: distribution of a gene (mnxg) encoding a putative manganese-oxidizing enzyme in bacillus species. | several bacillus and paenibacillus species were isolated from fe and mn oxide minerals precipitating at a deep subsurface oxic-anoxic interface at henderson molybdenum mine, empire, co. the isolates were investigated for their mn(ii)-oxidizing potential and interrogated for possession of the mnxg gene, a gene that codes for a putative mn(ii)-oxidizing enzyme in bacillus species. seven of eight bacillus species were capable of mn(ii) oxidation; however, the mnxg gene was detected in only one isol ... | 2008 | 18849460 |
| iron requirement for mn(ii) oxidation by leptothrix discophora ss-1. | a common form of biocatalysis of mn(ii) oxidation results in the formation of biogenic mn(iii, iv) oxides and is a key reaction in the geochemical cycling of mn. in this study, we grew the model mn(ii)-oxidizing bacterium leptothrix discophora ss-1 in media with limited iron (0.1 microm iron/5.8 mm pyruvate) and sufficient iron (0.2 microm iron/5.8 mm pyruvate). the influence of iron on the rate of extracellular mn(ii) oxidation was evaluated. cultures in which cell growth was limited by iron ex ... | 2009 | 19114505 |
| iron requirement for mn(ii) oxidation by leptothrix discophora ss-1. | a common form of biocatalysis of mn(ii) oxidation results in the formation of biogenic mn(iii, iv) oxides and is a key reaction in the geochemical cycling of mn. in this study, we grew the model mn(ii)-oxidizing bacterium leptothrix discophora ss-1 in media with limited iron (0.1 microm iron/5.8 mm pyruvate) and sufficient iron (0.2 microm iron/5.8 mm pyruvate). the influence of iron on the rate of extracellular mn(ii) oxidation was evaluated. cultures in which cell growth was limited by iron ex ... | 2009 | 19114505 |
| mn(ii) oxidation is catalyzed by heme peroxidases in "aurantimonas manganoxydans" strain si85-9a1 and erythrobacter sp. strain sd-21. | a new type of manganese-oxidizing enzyme has been identified in two alphaproteobacteria, "aurantimonas manganoxydans" strain si85-9a1 and erythrobacter sp. strain sd-21. these proteins were identified by tandem mass spectrometry of manganese-oxidizing bands visualized by native polyacrylamide gel electrophoresis in-gel activity assays and fast protein liquid chromatography-purified proteins. proteins of both alphaproteobacteria contain animal heme peroxidase and hemolysin-type calcium binding do ... | 2009 | 19411418 |
| aurantimonas manganoxydans, sp. nov. and aurantimonas litoralis, sp. nov.: mn(ii) oxidizing representatives of a globally distributed clade of alpha-proteobacteria from the order rhizobiales. | several closely related mn(ii)-oxidizing alpha-proteobacteria were isolated from very different marine environments: strain si85-9a1 from the oxic/anoxic interface of a stratified canadian fjord, strain htcc 2156 from the surface waters off the oregon coast, and strain ae01 from the dorsal surface of a hydrothermal vent tubeworm. 16s rrna analysis reveals that these isolates are part of a tight phylogenetic cluster with previously characterized members of the genus aurantimonas. other organisms ... | 2009 | 19768133 |
| identification of a two-component regulatory pathway essential for mn(ii) oxidation in pseudomonas putida gb-1. | bacterial manganese(ii) oxidation has a profound impact on the biogeochemical cycling of mn and the availability of the trace metals adsorbed to the surfaces of solid mn(iii, iv) oxides. the mn(ii) oxidase enzyme was tentatively identified in pseudomonas putida gb-1 via transposon mutagenesis: the mutant strain gb-1-007, which fails to oxidize mn(ii), harbors a transposon insertion in the gene cuma. cuma encodes a putative multicopper oxidase (mco), a class of enzymes implicated in mn(ii) oxidat ... | 2010 | 20038702 |
| identification of a two-component regulatory pathway essential for mn(ii) oxidation in pseudomonas putida gb-1. | bacterial manganese(ii) oxidation has a profound impact on the biogeochemical cycling of mn and the availability of the trace metals adsorbed to the surfaces of solid mn(iii, iv) oxides. the mn(ii) oxidase enzyme was tentatively identified in pseudomonas putida gb-1 via transposon mutagenesis: the mutant strain gb-1-007, which fails to oxidize mn(ii), harbors a transposon insertion in the gene cuma. cuma encodes a putative multicopper oxidase (mco), a class of enzymes implicated in mn(ii) oxidat ... | 2010 | 20038702 |
| manganese-oxidizing bacteria mediate the degradation of 17α-ethinylestradiol. | manganese (ii) and manganese-oxidizing bacteria were used as an efficient biological system for the degradation of the xenoestrogen 17α-ethinylestradiol (ee2) at trace concentrations. mn(2+)-derived higher oxidation states of mn (mn(3+), mn(4+)) by mn(2+)-oxidizing bacteria mediate the oxidative cleavage of the polycyclic target compound ee2. the presence of manganese (ii) was found to be essential for the degradation of ee2 by leptothrix discophora, pseudomonas putida mb1, p. putida mb6 and p. ... | 2008 | 21261871 |
| isolation and characterization of a mn(ii)-oxidizing bacillus strain from the demosponge suberites domuncula. | in this study we demonstrate that the demosponge suberites domuncula harbors a mn(ii)-oxidizing bacterium, a bacillus strain, termed bac-subdo-03. our studies showed that mn(ii) stimulates bacterial growth and induces sporulation. moreover, we show that these bacteria immobilize manganese on their cell surface. comparison of the 16s rdna sequence allowed the grouping of bac-subdo-03 to the mn-precipitating bacteria. analysis of the spore cell wall revealed that it contains an mn(ii)-oxidizing en ... | 2010 | 21339943 |
| isolation and characterization of a mn(ii)-oxidizing bacillus strain from the demosponge suberites domuncula. | in this study we demonstrate that the demosponge suberites domuncula harbors a mn(ii)-oxidizing bacterium, a bacillus strain, termed bac-subdo-03. our studies showed that mn(ii) stimulates bacterial growth and induces sporulation. moreover, we show that these bacteria immobilize manganese on their cell surface. comparison of the 16s rdna sequence allowed the grouping of bac-subdo-03 to the mn-precipitating bacteria. analysis of the spore cell wall revealed that it contains an mn(ii)-oxidizing en ... | 2010 | 21339943 |
| Structural and spatial associations between Fe, O, and C in the network structure of the Leptothrix ochracea sheath surface. | The structural and spatial associations of Fe with O and C in the outer coat fibers of the Leptothrix ochracea sheath were shown to be substantially similar to the stalk fibers of Gallionella ferruginea, i.e., a central C core, probably of bacterial origin, and aquatic Fe interacting with O at the surface of the core. | 2011 | 21926209 |
| enumeration and detection of anaerobic ferrous iron-oxidizing, nitrate-reducing bacteria from diverse european sediments. | anaerobic, nitrate-dependent microbial oxidation of ferrous iron was recently recognized as a new type of metabolism. in order to study the occurrence of three novel groups of ferrous iron-oxidizing, nitrate-reducing bacteria (represented by strains brg1, brg2, and brg3), 16s rrna-targeted oligonucleotide probes were developed. in pure-culture experiments, these probes were shown to be suitable for fluorescent in situ hybridization, as well as for hybridization analysis of denaturing gradient ge ... | 1998 | 9835573 |
| a dna microarray platform based on direct detection of rrna for characterization of freshwater sediment-related prokaryotic communities. | a dna microarray platform for the characterization of bacterial communities in freshwater sediments based on a heterogeneous set of 70 16s rrna-targeted oligonucleotide probes and directly labeled environmental rna was developed and evaluated. application of a simple protocol for the efficient background blocking of aminosilane-coated slides resulted in an improved signal-to-noise ratio and a detection limit of 10 ng for particular 16s rrna targets. an initial specificity test of the system usin ... | 2006 | 16820477 |
| selective phylogenetic analysis targeted at 16s rrna genes of thermophiles and hyperthermophiles in deep-subsurface geothermal environments. | deep-subsurface samples obtained by deep drilling are likely to be contaminated with mesophilic microorganisms in the drilling fluid, and this could affect determination of the community structure of the geothermal microflora using 16s rrna gene clone library analysis. to eliminate possible contamination by pcr-amplified 16s rrna genes from mesophiles, a combined thermal denaturation and enzyme digestion method, based on a strong correlation between the g+c content of the 16s rrna gene and the o ... | 2006 | 16391020 |
| outlook for benefits of sediment microbial fuel cells with two bio-electrodes. | the benefits of sediment microbial fuel cells (smfcs) go beyond energy generation for low-power applications. aside from producing electrical energy, smfcs can enhance the oxidation of reduced compounds at the anode, thus bringing about the removal of excessive or unwanted reducing equivalents from submerged soils. moreover, an smfc could be applied to control redox-dependent processes in sediment layers. several cathodic reactions that may drive these sediment oxidation reactions are examined. ... | 2008 | 21261866 |
| isolation of bacteria whose growth is dependent on high levels of co2 and implications of their potential diversity. | although some bacteria require an atmosphere with high co(2) levels for their growth, co(2) is not generally supplied to conventional screening cultures. here, we isolated 84 bacterial strains exhibiting high-co(2) dependence. their phylogenetic affiliations imply that high-co(2) culture has potential as an effective method to isolate unknown microorganisms. | 2008 | 18487395 |
| promotion of mn(ii) oxidation and remediation of coal mine drainage in passive treatment systems by diverse fungal and bacterial communities. | biologically active, passive treatment systems are commonly employed for removing high concentrations of dissolved mn(ii) from coal mine drainage (cmd). studies of microbial communities contributing to mn attenuation through the oxidation of mn(ii) to sparingly soluble mn(iii/iv) oxide minerals, however, have been sparse to date. this study reveals a diverse community of mn(ii)-oxidizing fungi and bacteria existing in several cmd treatment systems. | 2010 | 20495049 |
| species sorting and neutral processes are both important during the initial assembly of bacterial communities. | many studies have shown that species sorting, that is, the selection by local environmental conditions is important for the composition and assembly of bacterial communities. on the other hand, there are other studies that could show that bacterial communities are neutrally assembled. in this study, we implemented a microcosm experiment with the aim to determine, at the same time, the importance of species sorting and neutral processes for bacterial community assembly during the colonisation of ... | 2011 | 21270841 |
| population structure of manganese-oxidizing bacteria in stratified soils and properties of manganese oxide aggregates under manganese-complex medium enrichment. | manganese-oxidizing bacteria in the aquatic environment have been comprehensively investigated. however, little information is available about the distribution and biogeochemical significance of these bacteria in terrestrial soil environments. in this study, stratified soils were initially examined to investigate the community structure and diversity of manganese-oxidizing bacteria. total 344 culturable bacterial isolates from all substrata exhibited mn(ii)-oxidizing activities at the range of 1 ... | 2013 | 24069232 |
| microscale gradients of oxygen, hydrogen peroxide, and ph in freshwater cathodic biofilms. | cathodic reactions in biofilms employed in sediment microbial fuel cells is generally studied in the bulk phase. however, the cathodic biofilms affected by these reactions exist in microscale conditions in the biofilm and near the electrode surface that differ from the bulk phase. understanding these microscale conditions and relating them to cathodic biofilm performance is critical for better-performing cathodes. the goal of this research was to quantify the variation in oxygen, hydrogen peroxi ... | 2013 | 23766295 |
| cota, a multicopper oxidase from bacillus pumilus wh4, exhibits manganese-oxidase activity. | multicopper oxidases (mcos) are a family of enzymes that use copper ions as cofactors to oxidize various substrates. previous research has demonstrated that several mcos such as mnxg, mofa and moxa can act as putative mn(ii) oxidases. meanwhile, the endospore coat protein cota from bacillus species has been confirmed as a typical mco. to study the relationship between cota and the mn(ii) oxidation, the cota gene from a highly active mn(ii)-oxidizing strain bacillus pumilus wh4 was cloned and ove ... | 2013 | 23577125 |
| elimination of manganese(ii,iii) oxidation in pseudomonas putida gb-1 by a double knockout of two putative multicopper oxidase genes. | bacterial manganese(ii) oxidation impacts the redox cycling of mn, other elements, and compounds in the environment; therefore, it is important to understand the mechanisms of and enzymes responsible for mn(ii) oxidation. in several mn(ii)-oxidizing organisms, the identified mn(ii) oxidase belongs to either the multicopper oxidase (mco) or the heme peroxidase family of proteins. however, the identity of the oxidase in pseudomonas putida gb-1 has long remained unknown. to identify the p. putida g ... | 2013 | 23124227 |
| identification of mn(ii)-oxidizing bacteria from a low-ph contaminated former uranium mine. | biological mn oxidation is responsible for producing highly reactive and abundant mn oxide phases in the environment that can mitigate metal contamination. however, little is known about mn oxidation in low-ph environments, where metal contamination often is a problem as the result of mining activities. we isolated two mn(ii)-oxidizing bacteria (mob) at ph 5.5 (duganella isolate ab_14 and albidiferax isolate tb-2) and nine strains at ph 7 from a former uranium mining site. isolate tb-2 may contr ... | 2014 | 24928873 |
| high voltage electrochemiluminescence (ecl) as a new method for detection of pah during screening for pah-degrading microbial consortia. | the search for new bacterial consortia capable of removing pah from the environment is associated with the need to employ novel, simple, and economically efficient detection methods. a fluorimetric method (fl) as well as high voltage electrochemiluminescence (ecl) on a modified surface of an aluminum electrode were used in order to determine the changes in the concentrations of pah in the studied aqueous solutions. the ecl signal (the spectrum and emission intensity for a given wavelength) was d ... | 2015 | 26213425 |
| characterization of ph dependent mn(ii) oxidation strategies and formation of a bixbyite-like phase by mesorhizobium australicum t-g1. | despite the ubiquity of mn oxides in natural environments, there are only a few observations of biological mn(ii) oxidation at ph < 6. the lack of low ph mn-oxidizing bacteria (mob) isolates limits our understanding of how ph influences biological mn(ii) oxidation in extreme environments. here, we report that a novel mob isolate, mesorhizobium australicum strain t-g1, isolated from an acidic and metalliferous uranium mining area, can oxidize mn(ii) at both acidic and neutral ph using different e ... | 2015 | 26236307 |
| surface mn(ii) oxidation actuated by a multicopper oxidase in a soil bacterium leads to the formation of manganese oxide minerals. | in this manuscript, we report that a bacterial multicopper oxidase (mco266) catalyzes mn(ii) oxidation on the cell surface, resulting in the surface deposition of mn(iii) and mn(iv) oxides and the gradual formation of bulky oxide aggregates. these aggregates serve as nucleation centers for the formation of mn oxide micronodules and mn-rich sediments. a soil-borne escherichia coli with high mn(ii)-oxidizing activity formed mn(iii)/mn(iv) oxide deposit layers and aggregates under laboratory cultur ... | 2015 | 26039669 |
| absorption mechanisms of cu(2+) on a biogenic bixbyite-like mn2o3 produced by bacillus cua isolated from soil. | although most reported biogenic mn oxides are hexagonal birnessites, other types of biogenic mn oxides also commonly occur in the environment. however, sorption characteristics and underlying mechanisms of the adsorption of heavy-metal ions on these biogenic mn oxides are still rarely addressed. in this study, the sorption mechanisms of cu(ii) on a low valence biogenic mn oxide, poorly crystallized bixbyite-like mn2o3 (α-mn2o3), were investigated. | 2015 | 25987886 |
| treatment of leptothrix cells with ultrapure water poses a threat to their viability. | the genus leptothrix, a type of fe/mn-oxidizing bacteria, is characterized by its formation of an extracellular and microtubular sheath. although almost all sheaths harvested from natural aquatic environments are hollow, a few chained bacterial cells are occasionally seen within some sheaths of young stage. we previously reported that sheaths of leptothrix sp. strain oums1 cultured in artificial media became hollow with aging due to spontaneous autolysis within the sheaths. in this study, we inv ... | 2015 | 25634812 |
| manganese(iv) oxide production by acremonium sp. strain kr21-2 and extracellular mn(ii) oxidase activity. | ascomycetes that can deposit mn(iii, iv) oxides are widespread in aquatic and soil environments, yet the mechanism(s) involved in mn oxide deposition remains unclear. a mn(ii)-oxidizing ascomycete, acremonium sp. strain kr21-2, produced a mn oxide phase with filamentous nanostructures. x-ray absorption near-edge structure (xanes) spectroscopy showed that the mn phase was primarily mn(iv). we purified to homogeneity a laccase-like enzyme with mn(ii) oxidase activity from cultures of strain kr21-2 ... | 2006 | 17021194 |
| heterologous expression and characterization of the manganese-oxidizing protein from erythrobacter sp. strain sd21. | the manganese (mn)-oxidizing protein (mopa) from erythrobacter sp. strain sd21 is part of a unique enzymatic family that is capable of oxidizing soluble mn(ii). this enzyme contains two domains, an animal heme peroxidase domain, which contains the catalytic site, followed by a c-terminal calcium binding domain. different from the bacterial mn-oxidizing multicopper oxidase enzymes, little is known about mopa. to gain a better understanding of mopa and its role in mn(ii) oxidation, the 238-kda ful ... | 2014 | 25172859 |
| the influence of environmental conditions on kinetics of arsenite oxidation by manganese-oxides. | manganese-oxides are one of the most important minerals in soil due to their widespread distribution and high reactivity. despite their invaluable role in cycling many redox sensitive elements, numerous unknowns remain about the reactivity of different manganese-oxide minerals under varying conditions in natural systems. by altering temperature, ph, and concentration of arsenite we were able to determine how manganese-oxide reactivity changes with simulated environmental conditions. the interact ... | 2015 | 26388696 |
| microbial community analysis in the roots of aquatic plants and isolation of novel microbes including an organism of the candidate phylum op10. | a number of molecular ecological studies have revealed complex and unique microbial communities in various terrestrial plant roots; however, little is known about the microbial communities of aquatic plant roots in spite of their potential use for water quality improvement in aquatic environments (e.g. floating treatment wetland system). here, we report the microbial communities inhabiting the roots of emerged plants, reed (phragmites australis) and japanese loosestrife (lythrum anceps), collect ... | 2011 | 22791047 |
| microbial community analysis in the roots of aquatic plants and isolation of novel microbes including an organism of the candidate phylum op10. | a number of molecular ecological studies have revealed complex and unique microbial communities in various terrestrial plant roots; however, little is known about the microbial communities of aquatic plant roots in spite of their potential use for water quality improvement in aquatic environments (e.g. floating treatment wetland system). here, we report the microbial communities inhabiting the roots of emerged plants, reed (phragmites australis) and japanese loosestrife (lythrum anceps), collect ... | 2011 | 22791047 |
| removal and recovery of toxic silver ion using deep-sea bacterial generated biogenic manganese oxides. | products containing silver ion (ag(+)) are widely used, leading to a large amount of ag(+)-containing waste. the deep-sea manganese-oxidizing bacterium marinobacter sp. mni7-9 efficiently oxidizes mn(2+) to generate biogenic mn oxide (bmo). the potential of bmo for recovering metal ions by adsorption has been investigated for some ions but not for ag(+). the main aim of this study was to develop effective methods for adsorbing and recovering ag using bmo produced by marinobacter sp. mni7-9. in a ... | 2013 | 24312566 |
| metagenomic analyses of the autotrophic fe(ii)-oxidizing, nitrate-reducing enrichment culture ks. | nitrate-dependent ferrous iron [fe(ii)] oxidation (ndfo) is a well-recognized chemolithotrophic pathway in anoxic sediments. the neutrophilic chemolithoautotrophic enrichment culture ks originally obtained from a freshwater sediment (k. l. straub, m. benz, b. schink, and f. widdel, appl environ microbiol 62:1458-1460, 1996) has been used as a model system to study ndfo. however, the primary fe(ii) oxidizer in this culture has not been isolated, despite extensive efforts to do so. here, we presen ... | 2016 | 26896135 |