| isolation and characterization of an acidophilic, heterotrophic bacterium capable of oxidizing ferrous iron. | a heterotrophic bacterium, isolated from an acidic stream in a disused pyrite mine which contained copious growths of "acid streamers," displayed characteristics which differentiated it from previously described mesophilic acidophiles. the isolate was obligately acidophilic, with a ph range of 2.0 to 4.4 and an optimum ph of 3.0. the bacterium was unable to fix carbon dioxide but oxidized ferrous iron, although at a slower rate than either thiobacillus ferrooxidans or leptospirillum ferrooxidans ... | 1992 | 1622207 |
| thiobacillus ferrooxidans, a facultative hydrogen oxidizer. | the type strain (atcc 23270) and two other strains of thiobacillus ferrooxidans were able to grow by hydrogen oxidation, a feature not recognized before. when cultivated on h2, a hydrogenase was induced and the strains were less extremely acidophilic than during growth on sulfidic ores. cells of t. ferrooxidans grown on h2 and on ferrous iron showed 100% dna homology. hydrogen oxidation was not observed in eight other species of the genus thiobacillus and in leptospirillum ferrooxidans. | 1990 | 2275538 |
| cultural and phylogenetic analysis of mixed microbial populations found in natural and commercial bioleaching environments. | a range of autotrophic and heterotrophic enrichment cultures were established to determine the cultural bacterial diversity present in samples obtained from the acidic runoff of a chalcocite overburden heap and from laboratory-scale (1- to 4-liter) batch and continuous bioreactors which were being used for the commercial assessment of the bioleachability of zinc sulfide ore concentrates. strains identified as thiobacillus ferrooxidans, thiobacillus thiooxidans, "leptospirillum ferrooxidans," and ... | 1994 | 7517131 |
| bacterial populations in samples of bioleached copper ore as revealed by analysis of dna obtained before and after cultivation. | the composition of bacterial populations in copper bioleaching systems was investigated by analysis of dna obtained either directly from ores or leaching solutions or after laboratory cultures. this analysis consisted of the characterization of the spacer regions between the 16 and 23s genes in the bacterial rrna genetic loci after pcr amplification. the sizes of the spacer regions, amplified from dnas obtained from samples, were compared with the sizes of those obtained from cultures of the mai ... | 1996 | 8919792 |
| a tn7-like transposon is present in the glmus region of the obligately chemoautolithotrophic bacterium thiobacillus ferrooxidans. | the region downstream of the thiobacillus ferrooxidans atcc 33020 atp operon was examined, and the genes encoding n-acetylglucosamine-1-uridyltransferase (glmu) and glucosamine synthetase (glms) were found. this atpefhagdc-glmus gene order is identical to that of escherichia coli. the t. ferrooxidans glms gene was shown to complement e. coli glms mutants for growth on minimal medium lacking glucosamine. a tn7-like transposon, tn5468, was found inserted into the region immediately downstream of t ... | 1998 | 9603897 |
| molecular cloning, sequencing, and expression of a chemoreceptor gene from leptospirillum ferrooxidans. | we have cloned and sequenced a 2,262-bp chromosomal dna fragment from the chemolithoautotrophic acidophilic bacterium leptospirillum ferrooxidans. this dna contained an open reading frame for a 577-amino-acid protein showing several characteristics of the bacterial chemoreceptors and, therefore, we named this gene lcri for leptospirillum chemotaxis receptor i. this is the first sequence reported for a gene from l. ferrooxidans encoding a protein. the lcri gene showed both sigma 28-like and sigma ... | 1998 | 9647803 |
| importance of extracellular polymeric substances from thiobacillus ferrooxidans for bioleaching. | leaching bacteria such as thiobacillus ferrooxidans attach to pyrite or sulfur by means of extracellular polymeric substances (eps) (lipopolysaccharides). the primary attachment to pyrite at ph 2 is mediated by exopolymer-complexed iron(iii) ions in an electrochemical interaction with the negatively charged pyrite surface. eps from sulfur cells possess increased hydrophobic properties and do not attach to pyrite, indicating adaptability to the substrate or substratum. | 1998 | 9647862 |
| enzyme-linked immunofiltration assay to estimate attachment of thiobacilli to pyrite | an enzyme-linked immunofiltration assay (elifa) has been developed in order to estimate directly and specifically thiobacillus ferrooxidans attachment on sulfide minerals. this method derives from the enzyme-linked immunosorbent assay but is performed on filtration membranes which allow the retention of mineral particles for a subsequent immunoenzymatic reaction in microtiter plates. the polyclonal antiserum used in this study was raised against t. ferrooxidans dsm 583 and recognized cell surfac ... | 1998 | 9687454 |
| leaching of zinc sulfide by thiobacillus ferrooxidans: experiments with a controlled redox potential indicate no direct bacterial mechanism | the role of thiobacillus ferrooxidans in bacterial leaching of mineral sulfides is controversial. much of the controversy is due to the fact that the solution conditions, especially the concentrations of ferric and ferrous ions, change during experiments. the role of the bacteria would be more easily discernible if the concentrations of ferric and ferrous ions were maintained at set values throughout the experimental period. in this paper we report results obtained by using the constant redox po ... | 1998 | 9758769 |
| an immunological strategy to monitor in situ the phosphate starvation state in thiobacillus ferrooxidans | thiobacillus ferrooxidans is one of the chemolithoautotrophic bacteria important in industrial biomining operations. during the process of ore bioleaching, the microorganisms are subjected to several stressing conditions, including the lack of some essential nutrients, which can affect the rates and yields of bioleaching. when t. ferrooxidans is starved for phosphate, the cells respond by inducing the synthesis of several proteins, some of which are outer membrane proteins of high molecular weig ... | 1998 | 9835593 |
| potential role of thiobacillus caldus in arsenopyrite bioleaching | we investigated the potential role of the three strains of thiobacillus caldus (ku, bc13, and c-sh12) in arsenopyrite leaching in combination with a moderately thermophilic iron oxidizer, sulfobacillus thermosulfidooxidans. pure cultures of t. caldus and s. thermosulfidooxidans were used as well as defined mixed cultures. by measuring released iron, tetrathionate, and sulfur concentrations, we found that the presence of t. caldus ku and bc13 in the defined mixed culture lowered the concentration ... | 1999 | 9872756 |
| bacterial leaching of metal sulfides proceeds by two indirect mechanisms via thiosulfate or via polysulfides and sulfur | the acid-insoluble metal sulfides fes2, mos2, and ws2 are chemically attacked by iron(iii) hexahydrate ions, generating thiosulfate, which is oxidized to sulfuric acid. other metal sulfides are attacked by iron(iii) ions and by protons, resulting in the formation of elemental sulfur via intermediary polysulfides. sulfur is biooxidized to sulfuric acid. this explains leaching of metal sulfides by thiobacillus thiooxidans. | 1999 | 9872800 |
| leaching of pyrite by acidophilic heterotrophic iron-oxidizing bacteria in pure and mixed cultures. | seven strains of heterotrophic iron-oxidizing acidophilic bacteria were examined to determine their abilities to promote oxidative dissolution of pyrite (fes2) when they were grown in pure cultures and in mixed cultures with sulfur-oxidizing thiobacillus spp. only one of the isolates (strain t-24) oxidized pyrite when it was grown in pyrite-basal salts medium. however, when pyrite-containing cultures were supplemented with 0.02% (wt/vol) yeast extract, most of the isolates oxidized pyrite, and o ... | 1999 | 9925586 |
| mechanism of pyrite dissolution in the presence of thiobacillus ferrooxidans. | in spite of the environmental and commercial interests in the bacterial leaching of pyrite, two central questions have not been answered after more than 35 years of research: does thiobacillus ferrooxidans enhance the rate of leaching above that achieved by ferric sulfate solutions under the same conditions, and if so, how do the bacteria affect such an enhancement? experimental conditions of previous studies were such that the concentrations of ferric and ferrous ions changed substantially thro ... | 1999 | 10388693 |
| seasonal variations in microbial populations and environmental conditions in an extreme acid mine drainage environment. | microbial populations, their distributions, and their aquatic environments were studied over a year (1997) at an acid mine drainage (amd) site at iron mountain, calif. populations were quantified by fluorescence in situ hybridizations with group-specific probes. probes were used for the domains eucarya, bacteria, and archaea and the two species most widely studied and implicated for their role in amd production, thiobacillus ferrooxidans and leptospirillum ferrooxidans. results show that microbi ... | 1999 | 10427059 |
| leaching of zinc sulfide by thiobacillus ferrooxidans: bacterial oxidation of the sulfur product layer increases the rate of zinc sulfide dissolution at high concentrations of ferrous ions. | this paper reports the results of leaching experiments conducted with and without thiobacillus ferrooxidans at the same conditions in solution. the extent of leaching of zns with bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. a porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, while no sulfur is present on the surfaces of the bacterially leached particles. the analysis of the data using the shrink ... | 1999 | 10583978 |
| the chromosomal arsenic resistance genes of thiobacillus ferrooxidans have an unusual arrangement and confer increased arsenic and antimony resistance to escherichia coli. | the chromosomal arsenic resistance genes of the acidophilic, chemolithoautotrophic, biomining bacterium thiobacillus ferrooxidans were cloned and sequenced. homologues of four arsenic resistance genes, arsb, arsc, arsh, and a putative arsr gene, were identified. the t. ferrooxidans arsb (arsenite export) and arsc (arsenate reductase) gene products were functional when they were cloned in an escherichia coli ars deletion mutant and conferred increased resistance to arsenite, arsenate, and antimon ... | 2000 | 10788346 |
| evaluation of a fluorescent lectin-based staining technique for some acidophilic mining bacteria. | a fluorescence-labeled wheat germ agglutinin staining technique (r. k. sizemore et al., appl. environ. microbiol. 56:2245-2247, 1990) was modified and found to be effective for staining gram-positive, acidophilic mining bacteria. bacteria identified by others as being gram positive through 16s rrna sequence analyses, yet clustering near the divergence of that group, stained weakly. gram-negative bacteria did not stain. background staining of environmental samples was negligible, and pyrite and s ... | 2000 | 10788401 |
| development and application of small-subunit rrna probes for assessment of selected thiobacillus species and members of the genus acidiphilium. | culture-dependent studies have implicated sulfur-oxidizing bacteria as the causative agents of acid mine drainage and concrete corrosion in sewers. thiobacillus species are considered the major representatives of the acid-producing bacteria in these environments. small-subunit rrna genes from all of the thiobacillus and acidiphilium species catalogued by the ribosomal database project were identified and used to design oligonucleotide dna probes. two oligonucleotide probes were synthesized to co ... | 2000 | 10877807 |
| isolation of a new broad-host-range incq-like plasmid, ptc-f14, from the acidophilic bacterium acidithiobacillus caldus and analysis of the plasmid replicon. | a moderately thermophilic (45 to 50 degrees c), highly acidophilic (ph 1.5 to 2.5), chemolithotrophic acidithiobacillus caldus strain, f, was isolated from a biooxidation process used to treat nickel ore. trans-alternating field electrophoresis analysis of total dna from the a. caldus cells revealed two plasmids of approximately 14 and 45 kb. the 14-kb plasmid, designated ptc-f14, was cloned and shown by replacement of the cloning vector with a kanamycin resistance gene to be capable of autonomo ... | 2001 | 11344137 |
| ferric iron reduction by acidophilic heterotrophic bacteria. | fifty mesophilic and five moderately thermophilic strains of acidophilic heterotrophic bacteria were tested for the ability to reduce ferric iron in liquid and solid media under aerobic conditions; about 40% of the mesophiles (but none of the moderate thermophiles) displayed at least some capacity to reduce iron. both rates and extents of ferric iron reduction were highly strain dependent. no acidophilic heterotroph reduced nitrate or sulfate, and (limited) reduction of manganese(iv) was noted i ... | 1991 | 16348395 |
| existence of a hydrogen sulfide:ferric ion oxidoreductase in iron-oxidizing bacteria. | the existence of a hydrogen sulfide:ferric ion oxidoreductase, which catalyzes the oxidation of elemental sulfur with ferric ions as an electron acceptor to produce ferrous and sulfite ions, was assayed with washed intact cells and cell extracts of various kinds of iron-oxidizing bacteria, such as thiobacillus ferrooxidans 13598, 13661, 14119, 19859, 21834, 23270, and 33020 from the american type culture collection, leptospirillum ferrooxidans 2705 and 2391 from the deutsche sammlung von mikroor ... | 1992 | 16348640 |
| evaluation of leptospirillum ferrooxidans for leaching. | the importance of leptospirillum ferrooxidans for leach processes has been evaluated by studying the lithotrophic flora of three mine biotopes and a heap leaching operation, by percolation experiments with inoculated, sterilized ore, and by morphological, physiological, and genetic investigations of pure and mixed cultures of l. ferrooxidans, thiobacillus ferrooxidans, and thiobacillus thiooxidans. in biotopes of 20 degrees c or above, leptospirillum-like bacteria are as abundant as t. ferrooxid ... | 1992 | 16348642 |
| sensitivity of iron-oxidizing bacteria, thiobacillus ferrooxidans and leptospirillum ferrooxidans, to bisulfite ion. | when grown on iron-salt medium supplemented with the bisulfite ion, leptospirillum ferrooxidans was much more sensitive to the ion than was thiobacillus ferrooxidans. the causes of the sensitivity of l. ferrooxidans to the bisulfite ion were studied. the bisulfite ion completely inhibited the iron-oxidizing activities of l. ferrooxidans and t. ferrooxidans at 0.02 and 0.2 mm, respectively. a trapping reagent for the bisulfite ion, formaldehyde, completely reversed the inhibition. the treatment o ... | 1994 | 16349199 |
| macroscopic streamer growths in acidic, metal-rich mine waters in north wales consist of novel and remarkably simple bacterial communities. | the microbial composition of acid streamers (macroscopic biofilms) in acidic, metal-rich waters in two locations (an abandoned copper mine and a chalybeate spa) in north wales was studied using cultivation-based and biomolecular techniques. known chemolithotrophic and heterotrophic acidophiles were readily isolated from disrupted streamers, but they accounted for only <1 to 7% of the total microorganisms present. fluorescent in situ hybridization (fish) revealed that 80 to 90% of the microbes in ... | 2006 | 16517651 |
| sulfur chemistry in bacterial leaching of pyrite. | in the case of pyrite bioleaching by leptospirillum ferrooxidans, an organism without sulfur-oxidizing capacity, besides the production of tetra- and pentathionate, a considerable accumulation of elemental sulfur occurred. a similar result was obtained for chemical oxidation assays with acidic, sterile iron(iii) ion-containing solutions. in the case of thiobacillus ferrooxidans, only slight amounts of elemental sulfur were detectable because of the organism's capacity to oxidize sulfur compounds ... | 1996 | 16535406 |
| chemolithotrophic bacteria in copper ores leached at high sulfuric acid concentration. | extensive bacterial growth was observed when copper sulfide ores were leached with 0.6 n sulfuric acid. the bacterial population developed in this condition was examined by characterization of the spacer regions between the 16s and 23s rrna genetic loci obtained after pcr amplification of the dna extracted from the leached ore. the spacers observed had the sizes found in strains of "leptospirillum ferrooxidans" and thiobacillus thiooxidans, except for a larger one, approximately 560 bp long, tha ... | 1997 | 16535497 |
| bacterial community in copper sulfide ores inoculated and leached with solution from a commercial-scale copper leaching plant. | most copper bioleaching plants operate with a high concentration of sulfate salts caused by the continuous addition of sulfuric acid and the recycling of the leaching solution. since the bacteria involved in bioleaching have been generally isolated at low sulfate concentrations, the bacterial population in ores leached with the high-sulfate solution (1.25 m) employed in a copper production plant was investigated. the complexity of the original population was assessed by the length pattern of the ... | 1997 | 16535570 |
| succession of sulfur-oxidizing bacteria in the microbial community on corroding concrete in sewer systems. | microbially induced concrete corrosion (micc) in sewer systems has been a serious problem for a long time. a better understanding of the succession of microbial community members responsible for the production of sulfuric acid is essential for the efficient control of micc. in this study, the succession of sulfur-oxidizing bacteria (sob) in the bacterial community on corroding concrete in a sewer system in situ was investigated over 1 year by culture-independent 16s rrna gene-based molecular tec ... | 2007 | 17142362 |
| 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 |
| 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 |
| isolation, sequence analysis, and comparison of two plasmids (28 and 29 kilobases) from the biomining bacterium leptospirillum ferrooxidans atcc 49879. | two plasmids, of 28,878 bp and 28,012 bp, were isolated from leptospirillum ferrooxidans atcc 49879. altogether, a total of 67 open reading frames (orfs) were identified on both plasmids, of which 32 had predicted products with high homology to proteins of known function, while 11 orfs had predicted products with homology to previously identified proteins of unknown function. twenty-four orfs had products with no homologues in the genbank/ncbi database. an analysis of the orfs and other features ... | 2005 | 16269793 |
| 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 |
| 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 |
| genome-directed isolation of the key nitrogen fixer leptospirillum ferrodiazotrophum sp. nov. from an acidophilic microbial community. | analysis of assembled random shotgun sequence data from a low-diversity, subsurface acid mine drainage (amd) biofilm revealed a single nif operon. this was found on a genome fragment belonging to a member of leptospirillum group iii, a lineage in the nitrospirae phylum with no cultivated representatives. based on the prediction that this organism is solely responsible for nitrogen fixation in the community, we pursued a selective isolation strategy to obtain the organism in pure culture. an amd ... | 2005 | 16204553 |
| bacterial diversity in a mine water treatment plant. | we investigated the microbial community in a pilot plant for treatment of acid mine water by biological ferrous iron oxidation using clone library analysis and calculated statistical parameters for further characterization. the microbial community in the plant was conspicuously dominated by a group of betaproteobacteria affiliated with "ferribacter polymyxa". | 2009 | 19047391 |
| bacterial diversity in a mine water treatment plant. | we investigated the microbial community in a pilot plant for treatment of acid mine water by biological ferrous iron oxidation using clone library analysis and calculated statistical parameters for further characterization. the microbial community in the plant was conspicuously dominated by a group of betaproteobacteria affiliated with "ferribacter polymyxa". | 2009 | 19047391 |
| diversity and functional analysis of bacterial communities associated with natural hydrocarbon seeps in acidic soils at rainbow springs, yellowstone national park. | in this paper we describe the bacterial communities associated with natural hydrocarbon seeps in nonthermal soils at rainbow springs, yellowstone national park. soil chemical analysis revealed high sulfate concentrations and low ph values (ph 2.8 to 3.8), which are characteristic of acid-sulfate geothermal activity. the hydrocarbon composition of the seep soils consisted almost entirely of saturated, acyclic alkanes (e.g., n-alkanes with chain lengths of c15 to c30, as well as branched alkanes, ... | 2005 | 16204508 |
| an atypical kdpd homologue from the cyanobacterium anabaena sp. strain l-31: cloning, in vivo expression, and interaction with escherichia coli kdpd-ctd. | the kdpfabc operon of escherichia coli, coding for the high-affinity k(+) transport system kdpfabc, is transcriptionally regulated by the products of the adjacently located kdpde genes. the kdpd protein is a membrane-bound sensor kinase consisting of a large n-terminal domain and a c-terminal transmitter domain interconnected by four transmembrane segments (the transmembrane segments together with the c-terminal transmitter domain of kdpd are referred to as ctd), while kdpe is a cytosolic respon ... | 2005 | 15995207 |
| the bldc developmental locus of streptomyces coelicolor encodes a member of a family of small dna-binding proteins related to the dna-binding domains of the merr family. | the bldc locus, required for formation of aerial hyphae in streptomyces coelicolor, was localized by map-based cloning to the overlap between cosmids d17 and d25 of a minimal ordered library. subcloning and sequencing showed that bldc encodes a member of a previously unrecognized family of small (58- to 78-residue) dna-binding proteins, related to the dna-binding domains of the merr family of transcriptional activators. bldc family members are found in a wide range of gram-positive and gram-nega ... | 2005 | 15629942 |
| reduction of arsenic content in a complex galena concentrate by acidithiobacillus ferrooxidans. | bioleaching is a process that has been used in the past in mineral pretreatment of refractory sulfides, mainly in the gold, copper and uranium benefit. this technology has been proved to be cheaper, more efficient and environmentally friendly than roasting and high pressure moisture heating processes. so far the most studied microorganism in bioleaching is acidithiobacillus ferrooxidans. there are a few studies about the benefit of metals of low value through bioleaching. from all of these, ther ... | 2004 | 15482595 |
| immobilization of arsenite and ferric iron by acidithiobacillus ferrooxidans and its relevance to acid mine drainage. | weathering of the as-rich pyrite-rich tailings of the abandoned mining site of carnoulès (southeastern france) results in the formation of acid waters heavily loaded with arsenic. dissolved arsenic present in the seepage waters precipitates within a few meters from the bottom of the tailing dam in the presence of microorganisms. an acidithiobacillus ferrooxidans strain, referred to as cc1, was isolated from the effluents. this strain was able to remove arsenic from a defined synthetic medium onl ... | 2003 | 14532077 |
| microbial ecology of an extreme acidic environment, the tinto river. | the tinto river (huelva, southwestern spain) is an extreme environment with a rather constant acidic ph along the entire river and a high concentration of heavy metals. the extreme conditions of the tinto ecosystem are generated by the metabolic activity of chemolithotrophic microorganisms thriving in the rich complex sulfides of the iberian pyrite belt. molecular ecology techniques were used to analyze the diversity of this microbial community. the community's composition was studied by denatur ... | 2003 | 12902280 |
| production of glycolic acid by chemolithotrophic iron- and sulfur-oxidizing bacteria and its role in delineating and sustaining acidophilic sulfide mineral-oxidizing consortia. | glycolic acid was detected as an exudate in actively growing cultures of three chemolithotrophic acidophiles that are important in biomining operations, leptospirillum ferriphilum, acidithiobacillus (at.) ferrooxidans, and at. caldus. although similar concentrations of glycolic acid were found in all cases, the concentrations corresponded to ca. 24% of the total dissolved organic carbon (doc) in cultures of l. ferriphilum but only ca. 5% of the total doc in cultures of the two acidithiobacillus ... | 2010 | 19933342 |
| production of glycolic acid by chemolithotrophic iron- and sulfur-oxidizing bacteria and its role in delineating and sustaining acidophilic sulfide mineral-oxidizing consortia. | glycolic acid was detected as an exudate in actively growing cultures of three chemolithotrophic acidophiles that are important in biomining operations, leptospirillum ferriphilum, acidithiobacillus (at.) ferrooxidans, and at. caldus. although similar concentrations of glycolic acid were found in all cases, the concentrations corresponded to ca. 24% of the total dissolved organic carbon (doc) in cultures of l. ferriphilum but only ca. 5% of the total doc in cultures of the two acidithiobacillus ... | 2010 | 19933342 |
| isolation of sulfur reducing and oxidizing bacteria found in contaminated drywall. | drywall from china has been reported to release sulfur producing products which are corrosive to metals, result in noxious odors, and represent a significant health risk. it has been reported that these emissions produce medical symptoms such as respiratory or asthma type problems, sinusitis, gastrointestinal disorders, and vision problems in home owners and their household pets. we report here a method of identifying a causative agent for these emissions by sampling affected gypsum wallboard an ... | 2010 | 20386658 |
| gene function analysis in environmental isolates: the nif regulon of the strict iron oxidizing bacterium leptospirillum ferrooxidans. | a random genomic library from an environmental isolate of the gram-negative bacterium leptospirillum ferrooxidans has been printed on a microarray. gene expression analysis was carried out with total rna extracted from l. ferrooxidans cultures in the presence or absence of ammonium as nitrogen source under aerobic conditions. although practically nothing is known about the genome sequence of this bacterium, this approach allowed us the selection and sequencing of only those clones bearing genes ... | 2003 | 12808145 |
| enumeration and characterization of acidophilic microorganisms isolated from a pilot plant stirred-tank bioleaching operation. | microorganisms were enumerated and isolated on selective solid media from a pilot-scale stirred-tank bioleaching operation in which a polymetallic sulfide concentrate was subjected to biologically accelerated oxidation at 45 degrees c. four distinct prokaryotes were isolated: three bacteria (an acidithiobacillus caldus-like organism, a thermophilic leptospirillum sp., and a sulfobacillus sp.) and one archaeon (a ferroplasma-like isolate). the relative numbers of these prokaryotes changed in the ... | 2003 | 12676667 |
| an exported rhodanese-like protein is induced during growth of acidithiobacillus ferrooxidans in metal sulfides and different sulfur compounds. | by proteomic analysis we found a 21-kda protein (p21) from acidithiobacillus ferrooxidans atcc 19859 whose synthesis was greatly increased by growth of the bacteria in pyrite, thiosulfate, elemental sulfur, cus, and zns and was almost completely repressed by growth in ferrous iron. after we determined the n-terminal amino acid sequence of p21, we used the available preliminary genomic sequence of a. ferrooxidans atcc 23270 to isolate the dna region containing the p21 gene. the nucleotide sequenc ... | 2002 | 11916703 |
| molecular relationship between two groups of the genus leptospirillum and the finding that leptospirillum ferriphilum sp. nov. dominates south african commercial biooxidation tanks that operate at 40 degrees c. | iron-oxidizing bacteria belonging to the genus leptospirillum are of great importance in continuous-flow commercial biooxidation reactors, used for extracting metals from minerals, that operate at 40 degrees c or less. they also form part of the microbial community responsible for the generation of acid mine drainage. more than 16 isolates of leptospirilla were included in this study, and they were clearly divisible into two major groups. group i leptospirilla had g+c moles percent ratios within ... | 2002 | 11823226 |
| the hunt for living gold. the search for organisms in extreme environments yields useful enzymes for industry. | | 2001 | 11713183 |
| in situ characterization of nitrospira-like nitrite-oxidizing bacteria active in wastewater treatment plants. | uncultivated nitrospira-like bacteria in different biofilm and activated-sludge samples were investigated by cultivation-independent molecular approaches. initially, the phylogenetic affiliation of nitrospira-like bacteria in a nitrifying biofilm was determined by 16s rrna gene sequence analysis. subsequently, a phylogenetic consensus tree of the nitrospira phylum including all publicly available sequences was constructed. this analysis revealed that the genus nitrospira consists of at least fou ... | 2001 | 11679356 |
| isafe1, an isl3 family insertion sequence from acidithiobacillus ferrooxidans atcc 19859. | a 1.3-kb insertion sequence, termed isafe1 (u66426), from acidithiobacillus ferrooxidans atcc 19859 is described. isafe1 exhibits the features of a typical bacterial insertion sequence. it has 26-bp, imperfectly matched, terminal inverted repeats and an open reading frame (orf) that potentially encodes a transposase (tpase) of 404 amino acids (aab07489) with significant similarity to members of the isl3 family of insertion sequences. a potential ribosome-binding site and potential -10 and -35 pr ... | 2001 | 11418574 |
| influence of tomato genotype on growth of inoculated and indigenous bacteria in the spermosphere. | we previously demonstrated a genetic basis in tomato for support of the growth of a biological control agent, bacillus cereus uw85, in the spermosphere after seed inoculation (k. p. smith, j. handelsman, and r. m. goodman, proc. natl. acad. sci. usa 96:4786-4790, 1999). here we report results of studies examining the host effect on the support of growth of bacillus and pseudomonas strains, both inoculated on seeds and recruited from soil, using selected inbred tomato lines from the recombinant i ... | 2001 | 11157211 |
| comparison of acid mine drainage microbial communities in physically and geochemically distinct ecosystems. | this study presents population analyses of microbial communities inhabiting a site of extreme acid mine drainage (amd) production. the site is the inactive underground richmond mine at iron mountain, calif., where the weathering of a massive sulfide ore body (mostly pyrite) produces solutions with phs of approximately 0.5 to approximately 1.0. here we used a suite of oligonucleotide probes, designed from molecular data recently acquired from the site, to analyze a number of microbial environment ... | 2000 | 11055950 |
| phylogeny of microorganisms populating a thick, subaerial, predominantly lithotrophic biofilm at an extreme acid mine drainage site. | an unusually thick ( approximately 1 cm) slime developed on a slump of finely disseminated pyrite ore within an extreme acid mine drainage site at iron mountain, near redding, calif. the slime was studied over the period of 1 year. the subaerial form of the slime distinguished it from more typical submerged streamers. phylogenetic analysis of 16s rrna genes revealed a diversity of sequences that were mostly novel. nearest relatives to the majority of sequences came from iron-oxidizing acidophile ... | 2000 | 10966399 |
| rethinking proteasome evolution: two novel bacterial proteasomes. | the proteasome is a multisubunit structure that degrades proteins. protein degradation is an essential component of regulation because proteins can become misfolded, damaged, or unnecessary. proteasomes and their homologues vary greatly in complexity: from hslv (heat shock locus v), which is encoded by 1 gene in bacteria, to the eukaryotic 20s proteasome, which is encoded by more than 14 genes. despite this variation in complexity, all the proteasomes are composed of homologous subunits. we sear ... | 2008 | 18389302 |
| the molecular evolution of the qo motif. | quinol oxidation in the catalytic quinol oxidation site (q(o) site) of cytochrome (cyt) bc(1) complexes is the key step of the q cycle mechanism, which laid the ground for mitchell's chemiosmotic theory of energy conversion. bifurcated electron transfer upon quinol oxidation enables proton uptake and release on opposite membrane sides, thus generating a proton gradient that fuels atp synthesis in cellular respiration and photosynthesis. the q(o) site architecture formed by cyt b and rieske iron- ... | 2014 | 25115012 |
| microarray analysis of defined mycobacterium tuberculosis populations using rna amplification strategies. | the amplification of bacterial rna is required if complex host-pathogen interactions are to be studied where the recovery of bacterial rna is limited. here, using a whole genome mycobacterium tuberculosis microarray to measure cross-genome representation of amplified mrna populations, we have investigated two approaches to rna amplification using different priming strategies. the first using oligo-dt primers after polyadenylation of the bacterial rna, the second using a set of mycobacterial ampl ... | 2008 | 18298834 |
| novel nickel resistance genes from the rhizosphere metagenome of plants adapted to acid mine drainage. | metal resistance determinants have traditionally been found in cultivated bacteria. to search for genes involved in nickel resistance, we analyzed the bacterial community of the rhizosphere of erica andevalensis, an endemic heather which grows at the banks of the tinto river, a naturally metal-enriched and extremely acidic environment in southwestern spain. 16s rrna gene sequence analysis of rhizosphere dna revealed the presence of members of five phylogenetic groups of bacteria and the two main ... | 2007 | 17675438 |
| mobilizable incq-related plasmid carrying a new quinolone resistance gene, qnrs2, isolated from the bacterial community of a wastewater treatment plant. | plasmid-encoded quinolone resistance was previously reported for different bacteria isolated from patients not only in the united states and asia but also in europe. here we describe the isolation, by applying a new selection strategy, of the quinolone resistance plasmid pgnb2 from an activated sludge bacterial community of a wastewater treatment plant in germany. the hypersensitive escherichia coli strain kam3 carrying a mutation in the multidrug efflux system genes acrab was transformed with t ... | 2006 | 16940104 |
| extremophiles and their application to veterinary medicine. | : extremophiles are organisms that can grow and thrive in harsh conditions, e.g., extremes of temperature, ph, salinity, radiation, pressure and oxygen tension. thermophilic, halophilic and radiation-resistant organisms are all microbes, some of which are able to withstand multiple extremes. psychrophiles, or cold-loving organisms, include not only microbes, but fish that live in polar waters and animals that can withstand freezing. extremophiles are structurally adapted at a molecular level to ... | 2004 | 21851659 |
| whole-genome transcription profiling reveals genes up-regulated by growth on fucose in the human gut bacterium "roseburia inulinivorans". | "roseburia inulinivorans" is an anaerobic polysaccharide-utilizing firmicute bacterium from the human colon that was identified as a producer of butyric acid during growth on glucose, starch, or inulin. r. inulinivorans a2-194 is also able to grow on the host-derived sugar fucose, following a lag period, producing propionate and propanol as additional fermentation products. a shotgun genomic microarray was constructed and used to investigate the switch in gene expression that is involved in chan ... | 2006 | 16740940 |
| diversity of microorganisms in fe-as-rich acid mine drainage waters of carnoulès, france. | the acid waters (ph 2.7 to 3.4) originating from the carnoulès mine tailings contain high concentrations of dissolved arsenic (80 to 350 mg.liter(-1)), iron (750 to 2,700 mg.liter(-1)), and sulfate (2,000 to 7,500 mg.liter(-1)). during the first 30 m of downflow in reigous creek issuing from the mine tailings, 20 to 60% of the dissolved arsenic is removed by coprecipitation with fe(iii). the microbial communities along the creek have been characterized using terminal-restriction fragment length ... | 2006 | 16391091 |
| characterization of cytochrome 579, an unusual cytochrome isolated from an iron-oxidizing microbial community. | a novel, soluble cytochrome with an unusual visible spectral signature at 579 nm (cyt(579)) has been characterized after isolation from several different microbial biofilms collected in an extremely acidic ecosystem. previous proteogenomic studies of an fe(ii)-oxidizing community indicated that this abundant red cytochrome could be extracted from the biofilms with dilute sulfuric acid. here, we found that the fe(ii)-dependent reduction of cyt(579) was thermodynamically favorable at a ph of >3, r ... | 2008 | 18469132 |
| characterization of a bacterial community in an abandoned semiarid lead-zinc mine tailing site. | bacterial diversity in mine tailing microbial communities has not been thoroughly investigated despite the correlations that have been observed between the relative microbial diversity and the success of revegetation efforts at tailing sites. this study employed phylogenetic analyses of 16s rrna genes to compare the bacterial communities present in highly disturbed, extremely (ph 2.7) and moderately (ph 5.7) acidic lead-zinc mine tailing samples from a semiarid environment with those from a vege ... | 2008 | 18424534 |
| conserved amino acid sequence features in the alpha subunits of mofe, vfe, and fefe nitrogenases. | this study examines the structural features and phylogeny of the alpha subunits of 69 full-length nifd (mofe subunit), vnfd (vfe subunit), and anfd (fefe subunit) sequences. | 2009 | 19578539 |
| bioleaching genomics. | | 2009 | 21261924 |
| nitrospira-like bacteria associated with nitrite oxidation in freshwater aquaria. | oxidation of nitrite to nitrate in aquaria is typically attributed to bacteria belonging to the genus nitrobacter which are members of the alpha subdivision of the class proteobacteria. in order to identify bacteria responsible for nitrite oxidation in aquaria, clone libraries of rrna genes were developed from biofilms of several freshwater aquaria. analysis of the rdna libraries, along with results from denaturing gradient gel electrophoresis (dgge) on frequently sampled biofilms, indicated the ... | 1998 | 16349486 |
| structure of human j-type co-chaperone hscb reveals a tetracysteine metal-binding domain. | iron-sulfur proteins play indispensable roles in a broad range of biochemical processes. the biogenesis of iron-sulfur proteins is a complex process that has become a subject of extensive research. the final step of iron-sulfur protein assembly involves transfer of an iron-sulfur cluster from a cluster-donor to a cluster-acceptor protein. this process is facilitated by a specialized chaperone system, which consists of a molecular chaperone from the hsc70 family and a co-chaperone of the j-domain ... | 2008 | 18713742 |
| comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations. | carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. these bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. to have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine s ... | 2008 | 19055775 |
| medical bioremediation of age-related diseases. | abstract: catabolic insufficiency in humans leads to the gradual accumulation of a number of pathogenic compounds associated with age-related diseases, including atherosclerosis, alzheimer's disease, and macular degeneration. removal of these compounds is a widely researched therapeutic option, but the use of antibodies and endogenous human enzymes has failed to produce effective treatments, and may pose risks to cellular homeostasis. another alternative is "medical bioremediation," the use of m ... | 2009 | 19358742 |
| biofilm bacterial community structure in streams affected by acid mine drainage. | we examined the bacterial communities of epilithic biofilms in 17 streams which represented a gradient ranging from relatively pristine streams to streams highly impacted by acid mine drainage (amd). a combination of automated ribosomal intergenic spacer analysis with multivariate analysis and ordination provided a sensitive, high-throughput method to monitor the impact of amd on stream bacterial communities. significant differences in community structure were detected among neutral to alkaline ... | 2009 | 19363070 |
| community genomic and proteomic analyses of chemoautotrophic iron-oxidizing "leptospirillum rubarum" (group ii) and "leptospirillum ferrodiazotrophum" (group iii) bacteria in acid mine drainage biofilms. | we analyzed near-complete population (composite) genomic sequences for coexisting acidophilic iron-oxidizing leptospirillum group ii and iii bacteria (phylum nitrospirae) and an extrachromosomal plasmid from a richmond mine, iron mountain, ca, acid mine drainage biofilm. community proteomic analysis of the genomically characterized sample and two other biofilms identified 64.6% and 44.9% of the predicted proteins of leptospirillum groups ii and iii, respectively, and 20% of the predicted plasmid ... | 2009 | 19429552 |
| type iv pili of acidithiobacillus ferrooxidans are necessary for sliding, twitching motility, and adherence. | we used conventional methods to investigate the mechanism by which acidithiobacillus ferrooxidans colonizes a solid surface by assessing pili-mediated sliding, twitching motility, and adherence. a. ferrooxidans slided to form circular oxidized zones around each colony. this suggested that slide motility occurs through pili or flagella, though a. ferrooxidans strains atcc 19859 and atcc 23270 lack flagella. the results of reverse transcription-pcr demonstrated that the putative major pili gene of ... | 2010 | 19806397 |
| type iv pili of acidithiobacillus ferrooxidans are necessary for sliding, twitching motility, and adherence. | we used conventional methods to investigate the mechanism by which acidithiobacillus ferrooxidans colonizes a solid surface by assessing pili-mediated sliding, twitching motility, and adherence. a. ferrooxidans slided to form circular oxidized zones around each colony. this suggested that slide motility occurs through pili or flagella, though a. ferrooxidans strains atcc 19859 and atcc 23270 lack flagella. the results of reverse transcription-pcr demonstrated that the putative major pili gene of ... | 2010 | 19806397 |
| characterization of the human hsc20, an unusual dnaj type iii protein, involved in iron-sulfur cluster biogenesis. | the importance of mitochondrial iron-sulfur cluster (isc) biogenesis for human health has been well established, but the roles of some components of this critical pathway still remain uncharacterized in mammals. among them is human heat shock cognate protein 20 (hhsc20), the putative human homolog of the specialized dnaj type co-chaperones, which are crucial for bacterial and fungal isc assembly. here, we show that the human hsc20 protein can complement for its counterpart in yeast, jac1p, and i ... | 2010 | 20668094 |
| sorting out the mix in microbial genomics. | | 2008 | 19025554 |
| depth-dependent geochemical and microbiological gradients in fe(iii) deposits resulting from coal mine-derived acid mine drainage. | we evaluated the depth-dependent geochemistry and microbiology of sediments that have developed via the microbially-mediated oxidation of fe(ii) dissolved in acid mine drainage (amd), giving rise to a 8-10 cm deep "iron mound" that is composed primarily of fe(iii) (hydr)oxide phases. chemical analyses of iron mound sediments indicated a zone of maximal fe(iii) reducing bacterial activity at a depth of approximately 2.5 cm despite the availability of dissolved o2 at this depth. subsequently, fe(i ... | 2014 | 24860562 |
| use of an intelligent control system to evaluate multiparametric effects on iron oxidation by thermophilic bacteria | a learning-based intelligent control system, the bioexpert, was developed and applied to the evaluation of multiparametric effects on iron oxidation by enrichment cultures of moderately thermophilic, acidophilic mining bacteria. the control system acquired and analyzed the data and then selected and maintained the sets of conditions that were evaluated. through multiple iterations, the bioexpert selected sets of conditions that resulted in improved iron oxidation rates. the results obtained with ... | 1998 | 9797322 |
| rna secondary structure prediction by centroids in a boltzmann weighted ensemble. | prediction of rna secondary structure by free energy minimization has been the standard for over two decades. here we describe a novel method that forsakes this paradigm for predictions based on boltzmann-weighted structure ensemble. we introduce the notion of a centroid structure as a representative for a set of structures and describe a procedure for its identification. in comparison with the minimum free energy (mfe) structure using diverse types of structural rnas, the centroid of the ensemb ... | 2005 | 16043502 |
| characteristics and adaptability of iron- and sulfur-oxidizing microorganisms used for the recovery of metals from minerals and their concentrates. | microorganisms are used in large-scale heap or tank aeration processes for the commercial extraction of a variety of metals from their ores or concentrates. these include copper, cobalt, gold and, in the past, uranium. the metal solubilization processes are considered to be largely chemical with the microorganisms providing the chemicals and the space (exopolysaccharide layer) where the mineral dissolution reactions occur. temperatures at which these processes are carried out can vary from ambie ... | 2005 | 15877814 |
| environmental transcriptome analysis reveals physiological differences between biofilm and planktonic modes of life of the iron oxidizing bacteria leptospirillum spp. in their natural microbial community. | extreme acidic environments are characterized by their high metal content and lack of nutrients (oligotrophy). macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers). in the río tinto (spain), brown filaments develop under the water stream where the gram-negative iron-oxidizing bacteria leptospirillum spp. (l. ferrooxidans and l. ferriphilum) and acidithiobacillus ferrooxidans are abundant. these microorganisms play ... | 2010 | 20576116 |
| characterization of bacterial community structure in a drinking water distribution system during an occurrence of red water. | the role of bacteria in the occasional emergence of red water, which has been documented worldwide, has yet to be determined. to better understand the mechanisms that drive occurrences of red water, the bacterial community composition and the relative abundance of several functional bacterial groups in a water distribution system of beijing during a large-scale red water event were determined using several molecular methods. individual clone libraries of the 16s rrna gene were constructed for th ... | 2010 | 20851995 |
| ecophysiology of fe-cycling bacteria in acidic sediments. | using a combination of cultivation-dependent and -independent methods, this study aimed to elucidate the diversity of microorganisms involved in iron cycling and to resolve their in situ functional links in sediments of an acidic lignite mine lake. using six different media with ph values ranging from 2.5 to 4.3, 117 isolates were obtained that grouped into 38 different strains, including 27 putative new species with respect to the closest characterized strains. among the isolated strains, 22 st ... | 2010 | 20971876 |
| application of a depositional facies model to an acid mine drainage site. | lower red eyes is an acid mine drainage site in pennsylvania where low-ph fe(ii) oxidation has created a large, terraced iron mound downstream of an anoxic, acidic, metal-rich spring. aqueous chemistry, mineral precipitates, microbial communities, and laboratory-based fe(ii) oxidation rates for this site were analyzed in the context of a depositional facies model. depositional facies were defined as pools, terraces, or microterracettes based on cm-scale sediment morphology, irrespective of the d ... | 2010 | 21097582 |
| application of a depositional facies model to an acid mine drainage site. | lower red eyes is an acid mine drainage site in pennsylvania where low-ph fe(ii) oxidation has created a large, terraced iron mound downstream of an anoxic, acidic, metal-rich spring. aqueous chemistry, mineral precipitates, microbial communities, and laboratory-based fe(ii) oxidation rates for this site were analyzed in the context of a depositional facies model. depositional facies were defined as pools, terraces, or microterracettes based on cm-scale sediment morphology, irrespective of the d ... | 2010 | 21097582 |
| terminal oxidase diversity and function in "metallosphaera yellowstonensis": gene expression and protein modeling suggest mechanisms of fe(ii) oxidation in the sulfolobales. | "metallosphaera yellowstonensis" is a thermoacidophilic archaeon isolated from yellowstone national park that is capable of autotrophic growth using fe(ii), elemental s, or pyrite as electron donors. analysis of the draft genome sequence from m. yellowstonensis strain mk1 revealed seven different copies of heme copper oxidases (subunit i) in a total of five different terminal oxidase complexes, including doxbcef, foxabcdefghij, soxabc, and the soxm supercomplex, as well as a novel hypothetical t ... | 2011 | 21239558 |
| geomicrobiology of la zarza-perrunal acid mine effluent (iberian pyritic belt, spain). | effluent from la zarza-perrunal, a mine on the iberian pyrite belt, was chosen to be geomicrobiologically characterized along a 1,200-m stream length. the ph at the origin was 3.1, which decreased to 1.9 at the final downstream sampling site. the total iron concentration showed variations along the effluent, resulting from (i) significant hydrolysis and precipitation of fe(iii) (especially along the first reach of the stream) and (ii) concentration induced by evaporation (mostly in the last reac ... | 2011 | 21357431 |
| metatranscriptomic analysis of extremely halophilic viral communities. | hypersaline environments harbour the highest number of viruses reported for aquatic environments. in crystallizer ponds from solar salterns, haloviruses coexist with extremely halophilic archaea and bacteria and present a high diversity although little is known about their activity. in this work, we analyzed the viral expression in one crystallizer using a metatranscriptomic approach in which clones from a metaviromic library were immobilized in a microarray and used as probes against total mrna ... | 2011 | 21490689 |
| microbial diversity in anaerobic sediments at rio tinto, a naturally acidic environment with a high heavy metal content. | the tinto river is an extreme environment located at the core of the iberian pyritic belt (ipb). it is an unusual ecosystem due to its size (100 km long), constant acidic ph (mean ph, 2.3), and high concentration of heavy metals, iron, and sulfate in its waters, characteristics that make the tinto river basin comparable to acidic mine drainage (amd) systems. in this paper we present an extensive survey of the tinto river sediment microbiota using two culture-independent approaches: denaturing gr ... | 2011 | 21724883 |
| spatial and temporal analysis of the microbial community in the tailings of a pb-zn mine generating acidic drainage. | analysis of spatial and temporal variations in the microbial community in the abandoned tailings impoundment of a pb-zn mine revealed distinct microbial populations associated with the different oxidation stages of the tailings. although acidithiobacillus ferrooxidans and leptospirillum spp. were consistently present in the acidic tailings, acidophilic archaea, mostly ferroplasma acidiphilum, were predominant in the oxidized zones and the oxidation front, indicating their importance to generatio ... | 2011 | 21705549 |
| microbial community structure across the tree of life in the extreme río tinto. | understanding biotic versus abiotic forces that shape community structure is a fundamental aim of microbial ecology. the acidic and heavy metal extreme río tinto (rt) in southwestern spain provides a rare opportunity to conduct an ecosystem-wide biodiversity inventory at the level of all three domains of life, because diversity there is low and almost exclusively microbial. despite improvements in high-throughput dna sequencing, environmental biodiversity studies that use molecular metrics and c ... | 2010 | 20631808 |
| microbial community structure across the tree of life in the extreme río tinto. | understanding biotic versus abiotic forces that shape community structure is a fundamental aim of microbial ecology. the acidic and heavy metal extreme río tinto (rt) in southwestern spain provides a rare opportunity to conduct an ecosystem-wide biodiversity inventory at the level of all three domains of life, because diversity there is low and almost exclusively microbial. despite improvements in high-throughput dna sequencing, environmental biodiversity studies that use molecular metrics and c ... | 2010 | 20631808 |
| significance of microbial communities and interactions in safeguarding reactive mine tailings by ecological engineering. | pyritic mine tailings (mineral waste generated by metal mining) pose significant risk to the environment as point sources of acidic, metal-rich effluents (acid mine drainage [amd]). while the accelerated oxidative dissolution of pyrite and other sulfide minerals in tailings by acidophilic chemolithotrophic prokaryotes has been widely reported, other acidophiles (heterotrophic bacteria that catalyze the dissimilatory reduction of iron and sulfur) can reverse the reactions involved in amd genesis, ... | 2011 | 21965397 |
| contemporary environmental variation determines microbial diversity patterns in acid mine drainage. | a wide array of microorganisms survive and thrive in extreme environments. however, we know little about the patterns of, and controls over, their large-scale ecological distribution. to this end, we have applied a bar-coded 16s rrna pyrosequencing technology to explore the phylogenetic differentiation among 59 microbial communities from physically and geochemically diverse acid mine drainage (amd) sites across southeast china, revealing for the first time environmental variation as the major fa ... | 2012 | 23178673 |
| bacteria dialog with santa rosalia: are aggregations of cosmopolitan bacteria mainly explained by habitat filtering or by ecological interactions? | since the landmark santa rosalia paper by hutchinson, niche theory addresses the determinants of biodiversity in terms of both environmental and biological aspects. disentangling the role of habitat filtering and interactions with other species is critical for understanding microbial ecology. macroscopic biogeography explores hypothetical ecological interactions through the analysis of species associations. these methods have started to be incorporated into microbial ecology relatively recently, ... | 2014 | 25472003 |
| bacterial proteasome activator bpa (rv3780) is a novel ring-shaped interactor of the mycobacterial proteasome. | the occurrence of the proteasome in bacteria is limited to the phylum of actinobacteria, where it is maintained in parallel to the usual bacterial compartmentalizing proteases. the role it plays in these organisms is still not fully understood, but in the human pathogen mycobacterium tuberculosis (mtb) the proteasome supports persistence in the host. in complex with the ring-shaped atpase mpa (called arc in other actinobacteria), the proteasome can degrade proteins that have been post-translatio ... | 2014 | 25469515 |
| contemporary environmental variation determines microbial diversity patterns in acid mine drainage. | a wide array of microorganisms survive and thrive in extreme environments. however, we know little about the patterns of, and controls over, their large-scale ecological distribution. to this end, we have applied a bar-coded 16s rrna pyrosequencing technology to explore the phylogenetic differentiation among 59 microbial communities from physically and geochemically diverse acid mine drainage (amd) sites across southeast china, revealing for the first time environmental variation as the major fa ... | 2012 | 23178673 |
| the microbial ferrous wheel: iron cycling in terrestrial, freshwater, and marine environments. | | 2012 | 23118735 |