| molecular diversity of microbial community in acid mine drainages of yunfu sulfide mine. | two acid mine drainage (amd) samples were studied by a pcr-based cloning approach, which were from yunfu sulfide mine in guangdong province, china. a total of 15 operational taxonomic units (otus) were obtained from the two amd samples. the percentage of overlapped otus in two amd samples was 42.1%. phylogenetic analysis revealed that the bacterium in the two samples fell into four putative divisions, which were nitrospira, alpha-proteobacteria, beta-proteobacteria, and gamma-proteobacteria four ... | 2007 | 17177020 |
| differential expression of two bc1 complexes in the strict acidophilic chemolithoautotrophic bacterium acidithiobacillus ferrooxidans suggests a model for their respective roles in iron or sulfur oxidation. | three strains of the strict acidophilic chemolithoautotrophic acidithiobacillus ferrooxidans, including the type strain atcc 23270, contain a petiiabc gene cluster that encodes the three proteins, cytochrome c1, cytochrome b and a rieske protein, that constitute a bc1 electron-transfer complex. rt-pcr and northern blotting show that the petiiabc cluster is co-transcribed with cyca, encoding a cytochrome c belonging to the c4 family, sdra, encoding a putative short-chain dehydrogenase, and hip, e ... | 2007 | 17185539 |
| mineral and iron oxidation at low temperatures by pure and mixed cultures of acidophilic microorganisms. | an enrichment culture from a boreal sulfide mine environment containing a low-grade polymetallic ore was tested in column bioreactors for simulation of low temperature heap leaching. pcr-denaturing gradient gel electrophoresis and 16s rrna gene sequencing revealed the enrichment culture contained an acidithiobacillus ferrooxidans strain with high 16s rrna gene similarity to the psychrotolerant strain ss3 and a mesophilic leptospirillum ferrooxidans strain. as the mixed culture contained a strain ... | 2007 | 17187443 |
| the pio operon is essential for phototrophic fe(ii) oxidation in rhodopseudomonas palustris tie-1. | phototrophic fe(ii)-oxidizing bacteria couple the oxidation of ferrous iron [fe(ii)] to reductive co(2) fixation by using light energy, but until recently, little has been understood about the molecular basis for this process. here we report the discovery, with rhodopseudomonas palustris tie-1 as a model organism, of a three-gene operon, designated the pio operon (for phototrophic iron oxidation), that is necessary for phototrophic fe(ii) oxidation. the first gene in the operon, pioa, encodes a ... | 2007 | 17189359 |
| the cellular machinery of ferroplasma acidiphilum is iron-protein-dominated. | ferroplasma is a genus of the archaea, one of the three branches of the tree of life, and belongs to the order thermoplasmatales (euryarchaeota), which contains the most acidophilic microbes yet known. ferroplasma species live in acid mine drainage, acidic pools and environments containing sulphidic ores such as pyrite and characterized by ph values of 0-2 and high concentrations of ferrous iron and other heavy metals. f. acidiphilum strain y(t) is a chemoautotroph that grows optimally at ph 1.7 ... | 2007 | 17203061 |
| microbial communities in a porphyry copper tailings impoundment and their impact on the geochemical dynamics of the mine waste. | the distribution and diversity of acidophilic bacteria of a tailings impoundment at the la andina copper mine, chile, was examined. the tailings have low sulfide (1.7% pyrite equivalent) and carbonate (1.4% calcite equivalent) contents and are stratified into three distinct zones: a surface (0-70-80 cm) 'oxidation zone' characterized by low-ph (2.5-4), a 'neutralization zone' (70-80 to 300-400 cm) and an unaltered 'primary zone' below 400 cm. a combined cultivation-dependent and biomolecular app ... | 2007 | 17222129 |
| improved experimental and computational methodology for determining the kinetic equation and the extant kinetic constants of fe(ii) oxidation by acidithiobacillus ferrooxidans. | the variety of kinetics expressions encountered in the literature and the unreasonably broad range of values reported for the kinetics constants of acidithiobacillus ferrooxidans underscore the need for a unifying experimental procedure and for the development of a reliable kinetics equation. following an extensive and critical review of reported experimental techniques, a method based on batch ph-controlled kinetics experiments lasting less than one doubling time was developed for the determina ... | 2007 | 17261516 |
| volatilization and recovery of mercury from mercury-polluted soils and wastewaters using mercury-resistant acidithiobacillus ferrooxidans strains sug 2-2 and mon-1. | iron-oxidizing bacterium, acidithiobacillus ferrooxidans, is one of the most important bacteria for the bioleaching of copper and gold ores. in order to use the mercury reducing activity of a. ferrooxidans for the bioremediation of mercury, mercury-resistant a. ferrooxidans strains sug 2-2 and mon-1 were screened among 150 strains of iron-oxidizing bacteria isolated from natural environments. it was found that strains sug 2-2 and mon-1 have a novel ferrous iron-dependent mercury volatilization a ... | 2006 | 17273146 |
| bioleaching of chromium from tannery sludge by indigenous acidithiobacillus thiooxidans. | chromium in tannery sludge will cause serious environmental problems and is toxic to organisms. the acidophilic sulfur-oxidizing acidithiobacillus thiooxidans can leach heavy metals form urban and industrial wastes. this study examined the ability of an indigenous sulfur-oxidizing a. thiooxidans to leach chromium from tannery sludge. the results showed that the ph of sludge mixture inoculated with the indigenous a. thiooxidans decreased to around 2.0 after 4 days. after 6 days incubation in shak ... | 2007 | 17275185 |
| inter- and intraspecific genomic variability of the 16s-23s intergenic spacer regions (isr) in representatives of acidithiobacillus thiooxidans and acidithiobacillus ferrooxidans. | the complete sequences of 32 intergenic spacer regions (isr) from acidithiobacillus strains, including 29 field strains isolated from coal, copper, molybdenum mine wastes or sediment of different geoclimatic regions in china, reference strain atcc19859 and the type strains of the two species were determined. these data, together with other sequences available in the genbank database, were used to carry out the first detailed assessment of the inter- and intraspecific genomic variability of the i ... | 2007 | 17302937 |
| bacterial oxidation of ferrous iron at low temperatures. | this study comprises the first report of ferrous iron oxidation by psychrotolerant, acidophilic iron-oxidizing bacteria capable of growing at 5 degrees c. samples of mine drainage-impacted surface soils and sediments from the norilsk mining region (taimyr, siberia) and kristineberg (skellefte district, sweden) were inoculated into acidic ferrous sulfate media and incubated at 5 degrees c. iron oxidation was preceded by an approximately 3-month lag period that was reduced in subsequent cultures. ... | 2007 | 17304566 |
| uranium(vi) complexes with phospholipid model compounds--a laser spectroscopic study. | we present the complex formation of the uranyl ion (uo(2)(2+)) in the aqueous system with phosphocholine, o-phosphoethanolamine and o-phosphoserine. these phosphonates (r-o-po(3)(2-)) represent the hydrophilic head groups of phospholipids. the complexation was investigated by time-resolved laser-induced fluorescence spectroscopy (trlfs) at ph=2-6. an increase of the fluorescence intensity, connected with a strong red-shift of about 8 nm compared to the free uranyl ion, indicates a complex format ... | 2007 | 17320184 |
| [biodiversity of acidophiles in the sediment at an acid mine drainage site]. | a sediment sample was collected at an acid mine drainage site in anhui. the acidophiles composition and community structure in the sediment was studied with 16s rdna clone library and denaturing gradient gel electrophoresis (dgge). the results indicated that the acidophiles in the sediment were novel compared with the data in genbank. the acidophiles affiliated with acidobacteria, beta/gamma-proteobacteria, delta-proteobacteria, nitrospira, candidate division tm7, low g + c gram-positive. delta- ... | 2006 | 17326436 |
| the growth, ferrous iron oxidation and ultrastructure of acidithiobacillus ferrooxidans in the presence of dibutyl phthalate. | the iron-oxidizing bacteria acidithiobacillus ferrooxidans is an example of strictly chemolitotrophic extremophile occurring in acidic environments. the prime niche of these microorganisms is an environment with low ph and high concentrations of iron, sulfide minerals or sulfur. besides these environments, a. ferrooxidans is also isolated from heavy metal contaminated environments such as soil and sewage sludge and is known to be useful in bioremediation processes of these environments. in the c ... | 2006 | 17338273 |
| second acyl homoserine lactone production system in the extreme acidophile acidithiobacillus ferrooxidans. | the acidophilic proteobacterium acidithiobacillus ferrooxidans is involved in the industrial biorecovery of copper. it is found in acidic environments in biofilms and is important in the biogeochemical cycling of metals and nutrients. its genome contains a cluster of four genes, glyq, glyss, gph, and act, that are predicted to encode the alpha and beta subunits of glycine trna synthetase, a phosphatase, and an acyltransferase, respectively (genbank accession no. dq149607). act, cloned and expres ... | 2007 | 17351095 |
| bioinformatic prediction and experimental verification of fur-regulated genes in the extreme acidophile acidithiobacillus ferrooxidans. | the gamma-proteobacterium acidithiobacillus ferrooxidans lives in extremely acidic conditions (ph 2) and, unlike most organisms, is confronted with an abundant supply of soluble iron. it is also unusual in that it oxidizes iron as an energy source. consequently, it faces the challenging dual problems of (i) maintaining intracellular iron homeostasis when confronted with extremely high environmental loads of iron and (ii) of regulating the use of iron both as an energy source and as a metabolic m ... | 2007 | 17355989 |
| regulation of a glutamyl-trna synthetase by the heme status. | glutamyl-trna (glu-trna), formed by glu-trna synthetase (glurs), is a substrate for protein biosynthesis and tetrapyrrole formation by the c(5) pathway. in this route glu-trna is transformed to delta-aminolevulinic acid, the universal precursor of tetrapyrroles (e.g., heme and chlorophyll) by the action of glu-trna reductase (glutr) and glutamate semialdehyde aminotransferase. glutr is a target of feedback regulation by heme. in acidithiobacillus ferrooxidans, an acidophilic bacterium that expre ... | 2007 | 17360620 |
| bioleaching of metals from spent lithium ion secondary batteries using acidithiobacillus ferrooxidans. | bioleaching of spent lithium ion secondary batteries, containing licoo2, was attempted in this investigation. the present study was carried out using chemolithotrophic and acidophilic bacteria acidithiobacillus ferrooxidans, which utilized elemental sulfur and ferrous ion as the energy source to produce metabolites like sulfuric acids and ferric ion in the leaching medium. these metabolites helped dissolve metals from spent batteries. bio-dissolution of cobalt was found to be faster than lithium ... | 2008 | 17376665 |
| the sulfhydryl group of cys138 of rusticyanin from acidithiobacillus ferrooxidans is crucial for copper binding. | rusticyanin is a small blue copper protein isolated from acidithiobacillus ferrooxidans with extreme acid stability and redox potential. the protein is thought to be a principal component in the iron respiratory electron transport chain in this microorganism, but its exact role in electron transfer remains controversial. the gene of rusticyanin was cloned then overexpressed in escherichia coli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. it was r ... | 2007 | 17395555 |
| kinetic constant variability in bacterial oxidation of elemental sulfur. | wide ranges of growth yields on sulfur (from 2.4 x 10(10) to 8.1 x 10(11) cells g(-1)) and maximum sulfur oxidation rates (from 0.068 to 1.30 mmol liter(-1) h(-1)) of an acidithiobacillus ferrooxidans strain (ccm 4253) were observed in 73 batch cultures. no significant correlation between the constants was observed. changes of the michaelis constant for sulfur (from 0.46 to 15.5 mm) in resting cells were also noted. | 2007 | 17449698 |
| purification and some properties of thiosulfate dehydrogenase from acidithiobacillus ferrooxidans. | thiosulfate dehydrogenase was purified from acidithiobacillus ferrooxidans using three purification steps. the purification procedure involved ammonium sulfate fractionation, ion-exchange chromatography, and gel permeation chromatography. specific activity of the purified enzyme (after iec) was 3.26 nkat/mg, and yield of the enzyme was 78%. the purity of the enzyme was checked by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. the enzyme is a tetramer composed of fo ... | 2007 | 17454821 |
| a novel acidimicrobium species in continuous cultures of moderately thermophilic, mineral-sulfide-oxidizing acidophiles. | a novel species of acidimicrobium appeared to be the predominant ferrous iron oxidizer in a mixed culture that effected the continuous, efficient extraction of nickel from a mineral concentrate at 49 degrees c, but it was not isolated in pure culture. it outcompeted acidimicrobium ferrooxidans, which was expected to have a major role in iron oxidation in reactors gassed with air, and was outnumbered at 49 degrees c only by the sulfur-oxidizing acidithiobacillus caldus. sulfobacillus species were ... | 2007 | 17468267 |
| the isca from acidithiobacillus ferrooxidans is an iron-sulfur protein which assemble the [fe4s4] cluster with intracellular iron and sulfur. | isca was proposed to be involved in the iron-sulfur cluster assembly in acidithiobacillus ferrooxidans encoded by the iscsua operon, but the role of isca in the iron-sulfur cluster assembly still remains controversial. in this study, the isca from a. ferrooxidans atcc 23270 was successfully expressed in escherichia coli, and purified by affinity chromatography to homogeneity. to our surprise, the purified isca was observed to be an iron-sulfur protein according to maldi-tof-ms and spectra result ... | 2007 | 17470358 |
| adaptive changes of chemolithoautotrophic acidophilic sulfur-oxidizing bacteria during growth in sewage sludge. | a chemolithoauthotrophic, acidophilic, sulfur-oxidizing strain was isolated from sewage sludge and identified as acidithiobacillus thiooxidans. the morphology and physiology of the isolate grown in mineral medium or sterilized sewage sludge were investigated. morphological and ultrastructural differences between cells grown in mineral medium and sewage sludge were clearly visible. sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed some changes in the protein expression profiles i ... | 2006 | 17473888 |
| [acidification treatment of woolscouring effluent by using acidophilic thiobacillus]. | suspended solids dispersed in woolscouring effluent (wse) could be flocculated and precipitated in low ph. the aim of this study is to decrease ph in wse, result in liquid-solid separation and remove cod of wse through bio-acidification of acidophilic thiobacillus. acidophilic thiobacillus ts6 and sulfur powder as energy substance were inoculated and added into wse for incubation in shaker at 180 r/min and 30 degrees c for 12 d. the results showed that suspended solids in wse would flocculate an ... | 2007 | 17489202 |
| extremely acidic, pendulous cave wall biofilms from the frasassi cave system, italy. | the sulfide-rich frasassi cave system hosts an aphotic, subsurface microbial ecosystem including extremely acidic (ph 0-1), viscous biofilms (snottites) hanging from the cave walls. we investigated the diversity and population structure of snottites from three locations in the cave system using full cycle rrna methods and culturing. the snottites were composed primarily of bacteria related to acidithiobacillus species. other populations present in the snottites included thermoplasmata group arch ... | 2007 | 17504478 |
| the effects of acidithiobacillus ferrooxidans on the leaching of cobalt and strontium adsorbed onto soil particles. | bioleaching from soil artificially contaminated with analogues of radionuclides, co and sr, was carried out using a fe-oxidizing bacterium, acidithiobacillus ferrooxidans. due to bacterial metabolism, the ph and dissolved fe(3+) concentration in a biotic slurry decreased and increased respectively, over time, but the concentrations of co and sr extracted from the soil showed no significant enhancement compared with those under abiotic control. in both cases, co and sr were leached from the soil ... | 2007 | 17508258 |
| [characterization and heavy metal adsorption properties of schwertmannite synthesized by bacterial oxidation of ferrous sulfate solutions]. | an amorphous ferric hydroxysulfate named schwertmannite was synthesized by using bacterial oxidation of ferrous iron by resting a. ferrooxidans cells in acid ferrous sulfate solution (ph 2.5). the identification of the bacterially oxidized iron precipitate was carried out by sem, xrd, ftir and chemical analysis. results showed that resting cells of a. ferrooxidans lx5 could completely oxidize ferrous ions to ferric ions in the feso4-h2o system after 2 days of incubation. the solution ph decrease ... | 2007 | 17514978 |
| enhanced cr bioleaching efficiency from tannery sludge with coinoculation of acidithiobacillus thiooxidans ts6 and brettanomyces b65 in an air-lift reactor. | bioleaching process has been demonstrated to be an effective technology in removing cr from tannery sludge, but a large quantity of dissolved organic matter (dom) present in tannery sludge often exhibits a marked toxicity to chemolithoautotrophic bioleaching bacteria such as acidithiobacillus thiooxidans. the purpose of the present study was therefore to enhance cr bioleaching efficiencies through introducing sludge dom-degrading heterotrophic microorganism into the sulfur-based sludge bioleachi ... | 2007 | 17537479 |
| [isolation and characterization of acidiphilium strain teng-a and its metabolism of fe (iii) during pure- and mixed cultivation]. | an acidophilic, aerobic and chemoheterotrophic bacterial strain teng-a was isolated from acidic environmental samples collected at sulfidic hot springs of tengchong county, yunnan province, china. cells of strain teng-a was rod-shaped (0.6-0.8 microm x 1.0 - 1.5 microm), gram-negative, motile with flagella. strain teng-a grew well at temperature of 29-33 degrees c and at ph of 3.0-4.0. it used a wide variety of organic compounds for growth, but did not use ferrous iron, elemental sulfur, thiosul ... | 2007 | 17552248 |
| microbial communities and geochemical dynamics in an extremely acidic, metal-rich stream at an abandoned sulfide mine (huelva, spain) underpinned by two functional primary production systems. | an extremely acidic (ph 2.5-2.75) metal-rich stream draining an abandoned mine in the iberian pyrite belt, spain, was ramified with stratified macroscopic gelatinous microbial growths ('acid streamers' or 'mats'). microbial communities of streamer/mat growths sampled at different depths, as well as those present in the stream water itself, were analysed using a combined biomolecular and cultivation-based approach. the oxygen-depleted mine water was dominated by the chemolithotrophic facultative ... | 2007 | 17564609 |
| adaptive responses of chemolithoautotrophic acidophilic acidithiobacillus ferrooxidans to sewage sludge. | the aim of the present study was to investigate the phenotypic and genotypic variability of two strains of acidithiobacillus ferrooxidans genus during growth in sewage sludge. | 2007 | 17578413 |
| ribulose bisphosphate carboxylase activity and a calvin cycle gene cluster in sulfobacillus species. | the calvin-benson-bassham (cbb) cycle has been extensively studied in proteobacteria, cyanobacteria, algae and plants, but hardly at all in gram-positive bacteria. some characteristics of ribulose bisphosphate carboxylase/oxygenase (rubisco) and a cluster of potential cbb cycle genes in a gram-positive bacterium are described in this study with two species of sulfobacillus (gram-positive, facultatively autotrophic, mineral sulfide-oxidizing acidophiles). in contrast to the gram-negative, iron-ox ... | 2007 | 17600067 |
| microbial fuel cell operation with continuous biological ferrous iron oxidation of the catholyte. | the oxygen reduction rate at the cathode is a limiting factor in microbial fuel cell (mfc) performance. in our previous study, we showed the performance of an mfc with ferric iron (fe3+) reduction at the cathode. instead of oxygen, ferric iron was reduced to ferrous iron (fe2+) at the cathode with a bipolar membrane between the anode and cathode compartment. this resulted in a higher cathode potential than is usually obtained with oxygen on metal-based chemical catalysts in mfcs. in this study, ... | 2007 | 17612201 |
| [effect of initial ph on bioacidification treatment of woolscouring effluent]. | to remove biorefractory organic matter from woolscouring effluent, the bioacidification treatments pre-acidified by 4.5 mo x l(-1) sulfuric acid and bioacidified wastewater were performed through a 10 l stirred tank reactor. hydraulic retention time (hrt) for the treatment was obviously shortened through pre-acidification of woolscouring effluent. bioacidification treatment efficiency facilitated by pre-acidification with bioacidified wastewater was much higher than that by pre-acidification wit ... | 2007 | 17633639 |
| structure and quantum chemical analysis of nad+-dependent isocitrate dehydrogenase: hydride transfer and co-factor specificity. | the crystal structure of acidithiobacillus thiooxidans isocitrate dehydrogenase complexed with nad+ and citrate has been solved to a resolution of 1.9 a. the protein fold of this nad+-dependent enzyme shares a high similarity with those of nadp+-dependent bacterial icdhs. the nad+ and the citrate are clearly identified in the active site cleft with a well-defined electron density. asp-357 is the direct cofactor-specificity determinant that interacts with 2'-oh and 3'-oh of the adenosine ribose. ... | 2008 | 17634983 |
| expression, purification and characterization of a cysteine desulfurase, iscs, from acidithiobacillus ferrooxidans. | iron-sulfur clusters are one of the most common types of redox center in nature. three proteins of iscs (a cysteine desulfurase), iscu (a scaffold protein) and isca (an iron chaperon) encoded by the operon iscsua are involved in the iron-sulfur cluster assembly in acidithiobacillus ferrooxidans. in this study the gene of iscs from a. ferrooxidans atcc 23270 was cloned and expressed in escherichia coli, the protein was purified by one-step affinity chromatography to homogeneity. the molecular mas ... | 2007 | 17660944 |
| expression, purification and characterization of an iron-sulfur cluster assembly protein, iscu, from acidithiobacillus ferrooxidans. | an iron-sulfur cluster assembly protein, iscu, is encoded by the operon iscsua in acidithiobacillus ferrooxidans. the gene of iscu was cloned and expressed in escherichia coli. the protein was purified by one-step affinity chromatography to homogeneity. the protein was in apo-form, the [fe(2)s(2)] cluster could be assembled in apoiscu with fe(2+) and sulfide in vitro, and in the presence of isca and iscs, the iscu could utilize l: -cysteine and fe(2+) to synthesize [fe(2)s(2)] cluster in the pro ... | 2007 | 17660945 |
| [bacterial diversity analysis of moderately thermophilic microflora enriched by different energy sources]. | bacterial biodiversities of three moderately thermophilic bioleaching microfloras grown at 50 degrees c on media with pyrite, chalcopyrite, and pure ferrous iron supplemented with sulfur as energy sources were investigated respectively. the 16s rrna genes of the microorganisms in the cultures flasks were pcr amplified and cloned to identify the bacterial species by comparative sequence analysis, the structural differences of microfloras enriched by different energy sources were compared. a total ... | 2007 | 17672291 |
| the effects of fe(ii) and fe(iii) concentration and initial ph on microbial leaching of low-grade sphalerite ore in a column reactor. | in this study the effects of initial concentration of fe(ii) and fe(iii) ions as well as initial ph on the bioleaching of a low-grade sphalerite ore in a leaching column over a period of 120 days with and without bacteria were investigated. four different modifications of medium were used as column feed solutions to investigate the effects of initial concentration of fe(ii) and fe(iii) ions on zinc extraction. the experiments were carried out using a bench-scale, column leaching reactor, which w ... | 2008 | 17698352 |
| bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect. | bioleaching of metals from hazardous spent hydro-processing catalysts was attempted in the second stage after growing the bacteria with sulfur in the first stage. the first stage involved transformation of elemental sulfur particles to sulfuric acid through an oxidation process by acidophilic bacteria. in the second stage, the acidic medium was utilized for the leaching process. nickel, vanadium and molybdenum contained within spent catalyst were leached from the solid materials to liquid medium ... | 2008 | 17825485 |
| regulation of a novel acidithiobacillus caldus gene cluster involved in metabolism of reduced inorganic sulfur compounds. | acidithiobacillus caldus has been proposed to play a role in the oxidation of reduced inorganic sulfur compounds (riscs) produced in industrial biomining of sulfidic minerals. here, we describe the regulation of a new cluster containing the gene encoding tetrathionate hydrolase (teth), a key enzyme in the risc metabolism of this bacterium. the cluster contains five cotranscribed genes, isac1, rsrr, rsrs, teth, and doxd, coding for a transposase, a two-component response regulator (rsrr and rsrs) ... | 2007 | 17873067 |
| microbial populations in acid mineral bioleaching systems of tong shankou copper mine, china. | to understand the composition and structure of microbial communities in different acid mineral bioleaching systems, and to present a more complete picture of microbially mediated acid mine drainage production. | 2007 | 17897227 |
| convergent evolution of a new arsenic binding site in the arsr/smtb family of metalloregulators. | acidithiobacillus ferrooxidans has an arsenic resistance operon that is controlled by an as(iii)-responsive transcriptional repressor, afarsr, a member of the arsr/smtb family of metalloregulators. afarsr lacks the as(iii) binding site of the arsrs from plasmid r773 and escherichia coli, which have a cys(32)-val-cys(34)-asp-leu-cys(37) sequence in the dna binding site. in contrast, it has three cysteine residues, cys(95), cys(96), and cys(102), that are not present in the r773 and e. coli arsrs. ... | 2007 | 17897948 |
| identification of a gene encoding a tetrathionate hydrolase in acidithiobacillus ferrooxidans. | tetrathionate is one of the most important intermediates in dissimilatory sulfur oxidation and can itself be utilized as a sole energy source by some sulfur-oxidizing microorganisms. tetrathionate hydrolase (4thase) plays a significant role in tetrathionate oxidation and should catalyze the initial step in the oxidative dissimilation when sulfur-oxidizing bacteria are grown on tetrathionate. 4thase activity was detected in tetrathionate-grown acidithiobacillus ferrooxidans atcc 23270 cells but n ... | 2007 | 17904676 |
| expression, purification, and characterization of a [fe2s2] cluster containing ferredoxin from acidithiobacillus ferrooxidans. | the [2fe-2s] cluster containing ferredoxin has attracted much attention in recent years. genetic analyses show that it has an essential role in the maturation of various iron-sulfur (fe-s) proteins and functions as a component of the complex machinery responsible for the biogenesis of fe-s clusters. the gene of ferredoxin from a. ferrooxidans atcc 23270 was cloned, successfully expressed in escherichia coli, and purified by one-step affinity chromatography to homogeneity. the maldi-tof ms and sp ... | 2007 | 17909890 |
| periplasmic proteins of the extremophile acidithiobacillus ferrooxidans: a high throughput proteomics analysis. | acidithiobacillus ferrooxidans is a chemolithoautotrophic acidophile capable of obtaining energy by oxidizing ferrous iron or sulfur compounds such as metal sulfides. some of the proteins involved in these oxidations have been described as forming part of the periplasm of this extremophile. the detailed study of the periplasmic components constitutes an important area to understand the physiology and environmental interactions of microorganisms. proteomics analysis of the periplasmic fraction of ... | 2007 | 17911085 |
| quorum sensing detected by atomic force microscopy imaging of corrals surrounding multicellular arrangement of bacteria. | connectivity of the glycocalyx covering of small communities of acidithiobacillus ferrooxidans bacteria deposited on hydrophilic mica plates was imaged by atomic force microscopy. when part of the coverage was removed by water rinsing, an insoluble structure formed by corrals surrounding each individual bacterium was observed. a collective ring structure with clustered bacteria (>or=3) was observed, which indicates that the bacteria perceived the neighborhood in order to grow a protective struct ... | 2008 | 17943987 |
| prokaryotic community composition and ecology of floating macroscopic filaments from an extreme acidic environment, río tinto (sw, spain). | the prokaryotic diversity of macroscopic filaments located at the water surface in an extreme acidic environment, río tinto (sw, spain), has been analysed through denaturing gradient gel electrophoresis (dgge), cloning of 16s rrna genes and fluorescence in situ hybridization (fish). the dominant species present in the macrofilaments were acidithiobacillus ferrooxidans, leptospirillum ferrooxidans and acidiphilium spp., which represented the three main bacterial genera found in the water column o ... | 2007 | 17950555 |
| penetration analysis of elements and bioleaching treatment of spent refractory for recycling. | acidithiobacillus ferrooxidans atcc23270 and acidithiobacillus thiooxidans tm-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling. firstly, penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated. comparison on leaching efficiency by the strains atcc23270 and tm-32 found that the strain atcc23270 could treat larger amount of the refractories than t ... | 2007 | 17966524 |
| "bioshrouding": a novel approach for securing reactive mineral tailings. | a novel technique ("bioshrouding") for safeguarding highly reactive sulfidic mineral tailings deposits is proposed. in this, freshly milled wastes are colonised with ferric iron-reducing heterotrophic acidophilic bacteria that form biofilms on reactive mineral surfaces, thereby preventing or minimising colonisation by iron sulfide-oxidising chemolithotrophs such as acidithiobacillus ferrooxidans and leptospirillum spp. data from initial experiments showed that dissolution of pyrite could be redu ... | 2008 | 17975731 |
| thickness and surface density of extracellular polymers on acidithiobacillus ferrooxidans. | in vivo force microscopy measurements of acidithiobacillus ferrooxidans revealed a repulsive force that was due to the presence of extracellular polymers on the bacterium's surface. measured force-distance profiles were fit to steric force theory to estimate the density and thickness values of these exopolymers. the polymer densities were 3.4 x 10(16) to 7.1 x 10(16) molecules m(-2), and the equilibrium thickness was 29 nm. | 2008 | 17981935 |
| comparison of ferric iron generation by different species of acidophilic bacteria immobilized in packed-bed reactors. | flooded packed-bed bioreactors, prepared by immobilizing four different species of acidophilic iron-oxidizing bacteria on porous glass beads, were compared for their ferric iron-generating capacities when operated in batch and continuous flow modes over a period of up to 9 months, using a ferrous iron-rich synthetic liquor and acid mine drainage (amd) water. the bacteria used were strains of acidithiobacillus ferrooxidans, leptospirillum ferrooxidans, a ferrimicrobium-like isolate (tstr) and a n ... | 2008 | 17983721 |
| purification and characterization of sulfide:quinone oxidoreductase from an acidophilic iron-oxidizing bacterium, acidithiobacillus ferrooxidans. | sulfide:quinone oxidoreductase (sqr) was purified from membrane of acidophilic chemolithotrophic bacterium acidithiobacillus ferrooxidans nasf-1 cells grown on sulfur medium. it was composed of a single polypeptide with an apparent molecular mass of 47 kda. the apparent k(m) values for sulfide and ubiquinone were 42 and 14 mum respectively. the apparent optimum ph for the sqr activity was about 7.0. a gene encoding a putative sqr of a. ferrooxidans nasf-1 was cloned and sequenced. the gene was e ... | 2007 | 17986789 |
| increase in fe2+-producing activity during growth of acidithiobacillus ferrooxidans atcc23270 on sulfur. | when acidithiobacillus ferrooxidans atcc23270 cells, grown for many generations on sulfur were grown in sulfur medium with and without fe(3+), the bacterium markedly increased not only in iron oxidase activity but also in fe(2+)-producing sulfide:ferric ion oxidoreductase (sforase) activity during the early log phase, and retained part of these activities during the late log phase. the activity of sforase, which catalyzes the production of fe(2+) from fe(3+) and sulfur, of sulfur-grown cells was ... | 2007 | 17986795 |
| identification and characterization of four strains of acidithiobacillus ferrooxidans isolated from different sites in china. | four strains of acidithiobacillus ferrooxidans (a. ferrooxidans), af1, af2, af3 and afc, were isolated from samples with different geological sources using a 9k medium. these four isolates were identified as a. ferrooxidans by phenotypic and 16s rdna sequence analyses. all four isolates were able to use ferrous ion (fe(2+)), elemental sulfur (s0) or pyrite as a sole energy source, but they showed differences in ph optima and range of activity, optimum temperature of activity, resistance to chlor ... | 2009 | 17993268 |
| novel combination of atomic force microscopy and epifluorescence microscopy for visualization of leaching bacteria on pyrite. | bioleaching of metal sulfides is an interfacial process comprising the interactions of attached bacterial cells and bacterial extracellular polymeric substances with the surface of a mineral sulfide. such processes and the associated biofilms can be investigated at high spatial resolution using atomic force microscopy (afm). therefore, we visualized biofilms of the meso-acidophilic leaching bacterium acidithiobacillus ferrooxidans strain a2 on the metal sulfide pyrite with a newly developed comb ... | 2008 | 18039818 |
| construction of conjugative gene transfer system between e. coli and moderately thermophilic, extremely acidophilic acidithiobacillus caldus mth-04. | a genetic transfer system for introducing foreign genes to biomining microorganisms is urgently needed. thus, a conjugative gene transfer system was investigated for a moderately thermophilic, extremely acidophilic biomining bacterium, acidithiobacillus caldus mth-04. the broad-host-range incp plasmids rp4 and r68.45 were transferred directly into a. caldus mth-04 from escherichia coli by conjugation at relatively high frequencies. additionally the broad-host-range incq plasmids pjrd215, pvlt33, ... | 2007 | 18051368 |
| expression, purification and characterization of a high potential iron-sulfur protein from acidithiobacillus ferrooxidans. | the high potential iron-sulfur protein (hipip) is involved in the iron respiratory electron transport chain of acidithiobacillus ferrooxidans but its exact role is unclear. the gene of hipip from a. ferrooxidans atcc 23270 was cloned and expressed in escherichia coli, and the protein then purified by one-step affinity chromatography to homogeneity. the molecular mass of the hipip monomer was 7250.43 da by maldi-tof ms, indicating the presence of the [fe(4)s(4)] cluster. the optical and epr spect ... | 2008 | 18058071 |
| integrated bacterial process for the treatment of a spent nickel catalyst. | integrated biological processes involving the dissolution and subsequent precipitation have been used for the treatment of the spent material from the hydrogenation of vegetable oil containing a high-level of nickel. our results show that nickel was successfully leached using acidithiobacillus thiooxidans. the percentages of nickel leached using a. thiooxidans were higher than those obtained with dilute sulphuric acid solutions. due to the physical characteristics of the residue, the best result ... | 2008 | 18079054 |
| the genome sequence of the metal-mobilizing, extremely thermoacidophilic archaeon metallosphaera sedula provides insights into bioleaching-associated metabolism. | despite their taxonomic description, not all members of the order sulfolobales are capable of oxidizing reduced sulfur species, which, in addition to iron oxidation, is a desirable trait of biomining microorganisms. however, the complete genome sequence of the extremely thermoacidophilic archaeon metallosphaera sedula dsm 5348 (2.2 mb, approximately 2,300 open reading frames [orfs]) provides insights into biologically catalyzed metal sulfide oxidation. comparative genomics was used to identify p ... | 2008 | 18083856 |
| ph gradient-induced heterogeneity of fe(iii)-reducing microorganisms in coal mining-associated lake sediments. | lakes formed because of coal mining are characterized by low ph and high concentrations of fe(ii) and sulfate. the anoxic sediment is often separated into an upper acidic zone (ph 3; zone i) with large amounts of reactive iron and a deeper slightly acidic zone (ph 5.5; zone iii) with smaller amounts of iron. in this study, the impact of ph on the fe(iii)-reducing activities in both of these sediment zones was investigated, and molecular analyses that elucidated the sediment microbial diversity w ... | 2008 | 18083864 |
| microbial diversity in acid mineral bioleaching systems of dongxiang copper mine and yinshan lead-zinc mine. | to understand the composition and structure of microbial communities in acid mineral bioleaching systems, the molecular diversity of 16s rdna genes was examined using a pcr-based cloning approach. a total of 31 operational taxonomic units (otus) were obtained from the four samples taken from four different bioleaching sites in yinshan lead-zinc mine and dongxiang copper mine in jiangxi province, china. the percentages of overlapping otus between sites ranged from 22.2 to 50.0%. phylogenetic anal ... | 2008 | 18157706 |
| the chemolithoautotroph acidithiobacillus ferrooxidans can survive under phosphate-limiting conditions by expressing a c-p lyase operon that allows it to grow on phosphonates. | the chemolithoautotrophic bacterium acidithiobacillus ferrooxidans is of great importance in biomining operations. during the bioleaching of ores, microorganisms are subjected to a variety of environmental stresses and to the limitations of some nutrients, such as inorganic phosphate (p(i)), which is an essential component for all living cells. although the primary source of phosphorus for microorganisms is p(i), some bacteria are also able to metabolize p(i) esters (with a c-o-p bond) and phosp ... | 2008 | 18203861 |
| changes in nutrient profile of soil subjected to bioleaching for removal of heavy metals using acidithiobacillus thiooxidans. | studies were carried out to assess changes in nitrogen, phosphorus and potassium contents in soil during bioleaching of heavy metals from soil contaminated by tannery effluents. indigenous sulfur oxidizing bacteria acidithiobacillus thiooxidans isolated from the contaminated soil were used for bioremediation. solubilization efficiency of chromium, cadmium, copper and zinc from soil was 88, 93, 92 and 97%, respectively. however, loss of nitrogen, phosphorus and potassium from the soil was 30, 70 ... | 2008 | 18206305 |
| an oligonucleotide prokaryotic acidophile microarray: its validation and its use to monitor seasonal variations in extreme acidic environments with total environmental rna. | an oligonucleotide microarray that monitors prokaryotic diversity in extremely acidic environments has been developed. the oligonucleotide probes target most known acidophilic microorganisms, including members of the nitrospira phylum, acidithiobacillus genus, acidobacteria, sulfur reducing bacteria, actinobacteria and archaea of the ferroplasma and thermoplasma genera. the probes were tested for their specificity against the corresponding type strain by microarray hybridization using pcr-amplif ... | 2008 | 18248453 |
| biological ferrous sulfate oxidation by a. ferrooxidans immobilized on chitosan beads. | the immobilization of acidithiobacillus ferrooxidans cells on chitosan and cross-linked chitosan beads and the biooxidation of ferrous iron to ferric iron in a packed-bed bioreactor were studied. the biofilm formation was carried out by using a glass column reactor loaded with chitosan or cross-linked chitosan beads and 9 k medium previously inoculated with a. ferrooxidans cells. the immobilization cycles on the carrier matrix with the bioreactor operating in batch mode were compared. then, the ... | 2008 | 18294712 |
| [the dependence of intracellular atp level on the nutrition mode of the acidophilic bacteria sulfobacillus thermotolerans and alicyclobacillus tolerans]. | the dynamics of the atp pool in the aerobic spore-forming acidothermophilic mixotrophic bacteria sulfobacillus thermotolerans kr1t and alicyclobacillus tolerans k1t were studied in the course of their chemolithoheterotrophic, chemoorganoheterotrophic, and chemolithoautotrophic growth. it was established that, during mixotrophic growth, the maximum atp concentrations in the cells of s. thermotolerans kr1 and a. tolerans k1 were 3.8 and 0.6 nmol/mg protein, respectively. the atp concentrations in ... | 2007 | 18297864 |
| optimization of fe2 +/solids content ratio for a novel sludge heavy metal bioleaching process. | a novel bioleaching process, preincubation bioleaching (pb) has been recently developed in our laboratory for decontamination of heavy-metal-laden sewage sludge by removing the toxic low molecular weight organic acids using an isolated degradative yeast species. the objective of the present study was to optimize fe2+ /solids content ratio required for removing heavy metals from sewage sludge by using this novel process at high solids content. results from the present study showed that regardless ... | 2008 | 18309225 |
| expression, purification and characterization of the sulfite reductase hemo-subunit, sir-hp, from acidithiobacillus ferrooxidans. | sulfite reductase (sir) is a large and soluble enzyme which catalyzes the transfer of six electrons from nadph to sulfite to produce sulfide. the sulfite reductase flavoprotein (sir-fp) contains both fad and fmn, and the sulfite reductase hemoprotein (sir-hp) contains an iron-sulfur cluster coupled to a siroheme. the enzyme is arranged so that the redox cofactors in the fad-fmn-fe(4)s(4)-heme sequence make an electron pathway between nadph and sulfite. here we report the cloning, expression, and ... | 2008 | 18317695 |
| selection of leptospirillum ferrooxidans srpcbl and development for enhanced ferric regeneration in stirred tank and airlift column reactor. | presence of leptospirillum ferrooxidans plays significant role in ferric sulphate generation during bioleaching process. thus, an attempt was made to select l. ferrooxidans from the polymetallic concentrate leachate and further developed it for enhanced ferric iron regeneration from the leachate in shake flask, stirred tank and column reactor. when ferric to ferrous iron ratio in the shake flask reached to 20:1, l. ferrooxidans out competed acidithiobacillus ferrooxidans and accounted for more t ... | 2008 | 18325759 |
| characterization of arsenic resistant and arsenopyrite oxidizing acidithiobacillus ferrooxidans from hutti gold leachate and effluents. | four arsenic resistant ferrous oxidizers were isolated from hutti gold mine ltd. (hgml) samples. characterization of these isolates was done using conventional microbiological, biochemical and molecular methods. the ferrous oxidation rates with these isolates were 16, 48, 34 and 34 mg l(-1)h(-1) and 15, 47, 34 and 32 mg l(-1)h(-1) in absence and presence of 20 mm of arsenite (as3+) respectively. except isolate hgm 8, other three isolates showed 2.9-6.3% inhibition due to the presence of 20 mm ar ... | 2008 | 18367394 |
| genomic and phenotypic heterogeneity of acidithiobacillus spp. strains isolated from diverse habitats in china. | the genetic variability among 32 chinese acidithiobacillus spp. environmental isolates and four reference strains representing three recognized species of the genus acidithiobacillus was characterized by using a combination of molecular methods, namely restriction fragment length polymorphisms of pcr-amplified 16s rrna genes and 16s-23s rrna gene intergenic spacers, repetitive element pcr, arbitrarily primed pcr and 16s rrna gene sequence analyses. 16s rrna gene sequences revealed that all acidi ... | 2008 | 18373686 |
| gene expression of the arsenic resistance operon in chromobacterium violaceum atcc 12472. | chromobacterium violaceum atcc 12472 presents an arsrcb-type operon, which is involved in arsenic resistance. the regulating protein of this resistance system (arsr) does not have the small conserved site (elcvdcl) to link to the metalloid, as observed in escherichia coli, and is thus considered to be an atypical arsr protein, like that observed in acidithiobacillus ferrooxidans. in the present study, the gene expression profile of the ars operon under induction at different concentrations of ar ... | 2008 | 18388983 |
| isolation and characterization of acidithiobacillus ferrooxidans strain d3-2 active in copper bioleaching from a copper mine in chile. | acidithiobacillus ferrooxidans strain d3-2, which has a high copper bioleaching activity, was isolated from a low-grade sulfide ore dump in chile. the amounts of cu(2+) solubilized from 1% chalcopyrite (cufes(2)) concentrate medium (ph 2.5) by a. ferrooxidans strains d3-2, d3-6, and atcc 23270 and 33020 were 1360, 1080, 650, and 600 mg x l(-1) x 30 d(-1). the iron oxidase activities of d3-2, d3-6, and atcc 23270 were 11.7, 13.2, and 27.9 microl o(2) uptake x mg protein(-1) x min(-1). in contrast ... | 2008 | 18391470 |
| isolation and characterization of ferroplasma thermophilum sp. nov., a novel extremely acidophilic, moderately thermophilic archaeon and its role in bioleaching of chalcopyrite. | to isolate ferroplasma thermophilum l1(t) from a low ph environment and to understand its role in bioleaching of chalcopyrite. | 2008 | 18422958 |
| molecular insights into quorum sensing in acidithiobacillus ferrooxidans bacteria via molecular modelling of the transcriptional regulator afer and of the binding mode of long-chain acyl homoserine lactones. | amino acid sequence alignments of the transcriptional regulator afer, which is involved in type 1 quorum sensing (qs) in acidithiobacillus ferrooxidans bacteria, with other acyl homoserine lactone (ahl)-dependent qs regulators, revealed the presence of strictly or highly conserved residues located in the active site of these proteins. as a consequence, a model of afer was constructed to study the binding mode of long-chain ahls using molecular dynamics and subsequent rigid ligand docking. this s ... | 2008 | 18478280 |
| an effective method of dna extraction for bioleaching bacteria from acid mine drainage. | an effective and versatile method for microorganism lysis and direct extraction of dna from bioleaching bacteria was developed using pure cultures and an acid mine drainage (amd) sediment sample. in the described method, microorganisms are treated at three different incubation temperatures: boiling water incubation for 6-10 min, followed by 60 +/- 5 degrees c for 30 min, then 72 degrees c for 30 min. the extracted dna is purified using a phenol/chloroform/alcohol mixture and precipitated in abso ... | 2008 | 18481056 |
| microbiological and geochemical dynamics in simulated-heap leaching of a polymetallic sulfide ore. | the evolution of microbial populations involved in simulated-heap leaching of a polymetallic black schist sulfide ore (from the recently-commissioned talvivaara mine, finland) was monitored in aerated packed bed column reactors over a period of 40 weeks. the influence of ore particle size (2-6.5 mm and 6.5-12 mm) on changes in composition of the bioleaching microflora and mineral leaching dynamics in columns was investigated and compared to fine-grain (<2 microm) ore that was bioprocessed in sha ... | 2008 | 18496880 |
| culturable and molecular phylogenetic diversity of microorganisms in an open-dumped, extremely acidic pb/zn mine tailings. | a combination of cultivation-based and molecular-based approaches was used to reveal the culturable and molecular diversity of the microbes inhabiting an open-dumped pb/zn mine tailings that was undergoing intensive acid generation (ph 1.9). culturable bacteria found in the extremely acidic mine tailings were acidithiobacillus ferrooxidans, leptospirillum ferriphilum, sulfobacillus thermotolerans and acidiphilium cryptum, where the number of acidophilic heterotrophs was ten times higher than tha ... | 2008 | 18512002 |
| presence of a family of plasmids (29 to 65 kilobases) with a 26-kilobase common region in different strains of the sulfur-oxidizing bacterium acidithiobacillus caldus. | three large cryptic plasmids from different isolates of acidithiobacillus caldus were rescued by using an in vitro transposition system that delivers a kanamycin-selectable marker and an escherichia coli plasmid origin of replication. the largest of the plasmids, the 65-kb plasmid ptcm1, was isolated from a south african a. caldus strain, mng. this plasmid was sequenced and compared to that of ptcf1 (39 kb, from strain "f," south africa) and pc-sh12 (29 kb, from strain c-sh12, australia). with t ... | 2008 | 18515486 |
| ribb and ribba genes from acidithiobacillus ferrooxidans: expression levels under different growth conditions and phylogenetic analysis. | acidithiobacillus ferrooxidans is a gram-negative, chemolithoautotrophic bacterium involved in metal bioleaching. using the rna arbitrarily primed polymerase chain reaction (rap-pcr), we have identified several cdnas that were differentially expressed when a. ferrooxidans lr was submitted to potassium- and phosphate-limiting conditions. one of these cdnas showed similarity with ribb. an analysis of the a. ferrooxidans atcc 23270 genome, made available by the institute for genomic research, showe ... | 2008 | 18534824 |
| effects of dissolved low molecular weight organic acids on oxidation of ferrous iron by acidithiobacillus ferrooxidans. | a few researchers have reported on work concerning bioleaching of heavy-metal-contaminated soil using acidithiobacillus ferrooxidans, since this acidophile is sensitive to dissolved low molecular weight (lmw) organic acids. iron oxidation by a. ferrooxidans r2 as well as growth on ferrous iron was inhibited by a variety of dissolved lmw organic acids. growth experiments with ferrous iron as an oxidant showed that the inhibition capability sequence was formic acid>acetic acid>propionic acid>oxali ... | 2009 | 18554786 |
| biomodification of coal to remove mercury. | a biological process for removal of mercury from coal is under investigation. iron and sulfur oxidizing bacteria have previously been used for desulfurization of coal and for mineral mining. we have shown that removal of mercury from coal is also possible via the same principles. two pure cultures, leptospirillum ferrooxidans and acidithiobacillus ferrooxidans and four environmental consortium samples obtained from an acid mine drainage site were studied for mercury removal from coal. four diffe ... | 2006 | 18563664 |
| in vitro assembly of [fe4s4] cluster in high potential iron-sulfur protein from acidithiobacillus ferrooxidans. | high-potential iron-sulfur protein (hipip) has been proposed to be involved in the iron respiratory electron transport chain in acidithiobacillus ferrooxidans, which contains an [fe(4)s(4)] cluster. we report here the assembly of an [fe(4)s(4)] cluster in hipip from a. ferrooxidans atcc 23270 in vitro in the presence of fe(2+) and sulfide. the spectra and matrix-assisted laser desorption ionization-time of flight mass spectrometry results of holohipip confirmed that the iron-sulfur cluster was c ... | 2008 | 18574631 |
| bioleaching of zinc and iron from steel plant waste using acidithiobacillus ferrooxidans. | the bacterial leaching of zinc and iron from solid wastes at the isdemir iron and steel plant has been investigated using acidithiobacillus ferrooxidans as the bacterial agent. the effects of a range of operational parameters, including particle size, solids concentration and ph, on the efficiency of the bioleaching process were investigated. in each test, several variables were determined to assess the efficiency of leaching, including slurry ph and redox potential, temperature, bacteria popula ... | 2009 | 18581266 |
| quantitative microbial community analysis of three different sulfidic mine tailing dumps generating acid mine drainage. | the microbial communities of three different sulfidic and acidic mine waste tailing dumps located in botswana, germany, and sweden were quantitatively analyzed using quantitative real-time pcr (q-pcr), fluorescence in situ hybridization (fish), catalyzed reporter deposition-fish (card-fish), sybr green ii direct counting, and the most probable number (mpn) cultivation technique. depth profiles of cell numbers showed that the compositions of the microbial communities are greatly different at the ... | 2008 | 18586975 |
| biosynthesis of nanocrystal akaganéite from fecl2 solution oxidized by acidithiobacillus ferrooxidans cells. | akaganéite (beta-feooh) is a major iron oxyhydroxide component in some soils, marine concretions, and acid mine drainage environments. recently, synthetic beta-feooh has been found to be a promising absorbent in the treatment of metal-contaminated water. it has been recognized in previous study that akaganéite could be formed via fecl2 chemical oxidation under specific conditions. here we report a novel and simple method for akaganéite bioformation from fecl2 solution oxidized by acidithiobacill ... | 2008 | 18589982 |
| asp97 is a crucial residue involved in the ligation of the [fe4s4] cluster of isca from acidithiobacillus ferrooxidans. | isca was proposed to be involved in the iron-sulfur cluster assembly encoded by the iscsua operon, but the role of isca in the iron-sulfur cluster assembly still remains controversial. in our previous study, the isca from a. ferrooxidans was successfully expressed in escherichia coli, and purified to be a [fe4s4]-cluster-containing protein. cys35, cys99, and cys101 were important residues in ligating with the [fe4s4] cluster. in this study, asp97 was found to be another ligand for the iron-sulfu ... | 2008 | 18600049 |
| reduction of hg2+ with reduced mammalian cytochrome c by cytochrome c oxidase purified from a mercury-resistant acidithiobacillus ferrooxidans strain, mon-1. | acidithiobacillus ferrooxidans ap19-3, atcc 23270, and mon-1 are mercury-sensitive, moderately mercury-resistant, and highly mercury-resistant strains respectively. it is known that 2,3,5,6-tetramethyl-p-phenylendiamine (tmpd) and reduced cytochrome c are used as electron donors specific for cytochrome c oxidase. resting cells of strain mon-1 had tmpd oxidase activity and volatilized metal mercury with tmpd as an electron donor. cytochrome c oxidase purified from strain mon-1 reduced mercuric io ... | 2008 | 18603796 |
| insights into two high homogenous genes involved in copper homeostasis in acidithiobacillus ferrooxidans. | acidithiobacillus ferrooxidans, an important microorganism in bioleaching industry, has been sequenced recently, and from the annotated information, there are four genes involved in copper homeostasis. sequence analysis showed that two of them, afe0329 and afe0663, were high homologous (94.43% identity). with the polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) cloning approach, the differential gene expression of these two high homologous genes in a genome was succe ... | 2008 | 18618174 |
| a new iron-oxidizing/o2-reducing supercomplex spanning both inner and outer membranes, isolated from the extreme acidophile acidithiobacillus ferrooxidans. | the iron respiratory chain of the acidophilic bacterium acidithiobacillus ferrooxidans involves various metalloenzymes. here we demonstrate that the oxygen reduction pathway from ferrous iron (named downhill pathway) is organized as a supercomplex constituted of proteins located in the outer and inner membranes as well as in the periplasm. for the first time, the outer membrane-bound cytochrome c cyc2 was purified, and we showed that it is responsible for iron oxidation and determined that its r ... | 2008 | 18632666 |
| micro-raman analysis and afm imaging of acidithiobacillus ferrooxidans biofilm grown on uranium ore. | acidithiobacillus ferrooxidans biofilm grown on uranium ore substrate was analyzed by a micro-raman spectrometer and an atomic force microscope (afm). the bacterium employed for this study, a. ferrooxidans bm1, was isolated from a uranium mine (jaduguda, india). micro-raman analysis revealed the different constituents of molecular fragments present in microbial cells and in secreted extracellular polymeric substances (epss). afm images clearly revealed bacterial cells surrounded by eps. from ram ... | 2008 | 18640267 |
| bioleaching of chalcopyrite concentrate by a moderately thermophilic culture in a stirred tank reactor. | a mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainage samples collected from several chalcopyrite mines in china. such mixed culture can be used to effectively extract copper from chalcopyrite. furthermore, after being adapted to gradually increased concentration of chalcopyrite concentrate, the tolerance of the mixed culture to chalcopyrite concentrate was brought up to 80 g/l. the effects of several leaching parameters on copper recovery in stirred tank ... | 2009 | 18657418 |
| construction of arsb and teth mutants of the sulfur-oxidizing bacterium acidithiobacillus caldus by marker exchange. | acidithiobacillus caldus is a moderately thermophilic, acidophilic bacterium that has been reported to be the dominant sulfur oxidizer in stirred-tank processes used to treat gold-bearing arsenopyrite ores. it is also widely distributed in heap reactors used for the extraction of metals from ores. not only are these bacteria commercially important, they have an interesting physiology, the study of which has been restricted by the nonavailability of defined mutants. a recently reported conjugatio ... | 2008 | 18658286 |
| the rus operon genes are differentially regulated when acidithiobacillus ferrooxidans lr is kept in contact with metal sulfides. | acidithiobacillus ferrooxidans is a gram-negative bacterium that obtains energy from the oxidation of ferrous iron or reduced sulfur compounds. in this bacterium, the proteins encoded by the rus operon are involved in electron transfer from fe(ii) to o(2), and the first two proteins in this pathway also participate in the electron transfer pathway from fe(ii) to nad(p). in this work we analyzed the expression, by real-time pcr, of the eight genes from the rus operon when a. ferrooxidans lr was g ... | 2008 | 18665419 |
| 16s rdna and 16s-23s internal transcribed spacer sequence analyses reveal inter- and intraspecific acidithiobacillus phylogeny. | in order to contribute to our understanding of acidithiobacillus taxonomy, we determined 16s rdna sequences and the 16s-23s internally transcribed spacer (its) sequence of 35 chinese acidithiobacillus isolates and three reference strains representing three validly described species and used them to construct phylogenetic trees. the two phylogenetic trees were roughly similar topologically, and acidithiobacillus strains were assigned to eight phylogenetic groups. in addition, the results of phylo ... | 2008 | 18667572 |
| toxicity evaluation of complex metal mixtures using reduced metal concentrations: application to iron oxidation by acidithiobacillus ferrooxidans. | in this study, we investigated the inhibition effects of single and mixed heavy metal ions (zn2+, ni2+, cu2+, and cd2+) on iron oxidation by acidithiobacillus ferrooxidans. effects of metals on the iron oxidation activity of a. ferrooxidans are categorized into four types of patterns according to its oxidation behavior. the results indicated that the inhibition effects of the metals on the iron oxidation activity were noncompetitive inhibitions. we proposed a reduced inhibition model, along with ... | 2008 | 18667860 |
| reconstitution of iron oxidase from sulfur-grown acidithiobacillus ferrooxidans. | the iron oxidation system from sulfur-grown acidithiobacillus ferrooxidans atcc 23270 cells was reconstituted in vitro. purified rusticyanin, cytochrome c, and aa(3)-type cytochrome oxidase were essential for reconstitution. the iron-oxidizing activity of the reconstituted system was 3.3-fold higher than that of the cell extract from which these components were purified. | 2008 | 18791023 |
| toxicity of select organic acids to the slightly thermophilic acidophile acidithiobacillus caldus. | acidithiobacillus caldus is a thermophilic acidophile found in commercial biomining, acid mine drainage systems, and natural environments. previous work has characterized a. caldus as a chemolithotrophic autotroph capable of utilizing reduced sulfur compounds under aerobic conditions. organic acids are especially toxic to chemolithotrophs in low-ph environments, where they diffuse more readily into the cell and deprotonate within the cytoplasm. in the present study, the toxic effects of oxaloace ... | 2009 | 18803441 |