Increased Acid Resistance of the Archaeon, Metallosphaera sedula by Adaptive Laboratory Evolution
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ABSTRACT:
ORGANISM(S): Metallosphaera sedula
PROVIDER: GSE81414 | GEO | 2016/05/14
SECONDARY ACCESSION(S): PRJNA321497
REPOSITORIES: GEO
Similar Datasets
Project description:Extremely thermoacidophilic members of the Archaea such as the lithoautotroph, Metallosphaera sedula, are among the most acid resistant forms of life and are of great relevance in bioleaching. Here, adaptive laboratory evolution was used to enhance the acid resistance of this organism while genomics and transcriptomics were used in an effort to understand the molecular basis for this trait. Unlike the parental strain, the evolved derivative, M. sedula SARC-M1, grew well at pH of 0.90. Enargite (Cu3AsS4) bioleaching conducted at pH 1.20 demonstrated SARC-M1 leached 23.78% more copper relative to the parental strain. Genome re-sequencing identified two mutations in SARC-M1 including a nonsynonymous mutation in Msed_0408 (an amino acid permease) and a deletion in pseudogene Msed_1517. Transcriptomic studies by RNA-seq of wild type and evolved strains at various low pH values demonstrated there was enhanced expression of genes in M. sedula SARC-M1 encoding membrane complexes and enzymes that extrude protons or that catalyze proton-consuming reactions. In addition, M. sedula SARC-M1 exhibited reduced expression of genes encoding enzymes that catalyze proton-generating reactions. These unique genomic and transcriptomic features of M. sedula SARC-M1 support a model for increased acid resistance arising from enhanced control over cytoplasmic pH. 3 samples were analyzed: 1 control and 2 experimental samples
2016-05-14 | E-GEOD-81414 | biostudies-arrayexpress
Project description:Abstract: The crenarchaeal order Sulfolobales collectively contains at least five major terminal oxidase complexes. Based on genome sequence information, all five complexes are found only in Metallosphaera sedula and Sulfolobus tokodaii, the two sequenced Sulfolobales capable of iron oxidization. While specific respiratory complexes in certain Sulfolobales have been characterized previously as proton pumps for maintaining intracellular pH and generating proton motive force (pmf), their contribution to sulfur and iron biooxidation has not been considered. For M. sedula growing in the presence of ferrous iron and reduced inorganic sulfur compounds (RISCs), global transcriptional analysis was used to track the response of specific genes associated with these complexes, as well as other known and putative respiratory electron transport chain elements. ORFs from all five terminal oxidase or bc1-like complexes were stimulated on one or more conditions tested. Components of the fox (Msed0467-0489) and soxNL-cbsABA (Msed0500-0505) terminal/quinol oxidase clusters were triggered by ferrous iron, while the soxABCDD' terminal oxidase cluster (Msed0285-0291) were induced by tetrathionate and S°. Chemolithotrophic electron transport elements, including a putative tetrathionate hydrolase (Msed0804), a novel polysulfide/sulfur/DMSO reductase-like complex (Msed0812-0818), and a novel heterodisulfide reductase-like complex (Msed1542-1550), were also stimulated by RISCs. Furthermore, several hypothetical proteins were found to have strong responses to ferrous iron or RISCs, suggesting additional candidates in iron or sulfur oxidation-related pathways. From this analysis, a comprehensive model for electron transport in M. sedula could be proposed as the basis for examining specific details of iron and sulfur oxidation in this bioleaching archaeon.
2008-10-22 | GSE12044 | GEO
Project description:Extremely thermoacidophilic Crenarchaeota belonging to the family Sulfolobales flourish in hot acidic habitats that are strongly oxidizing. However, the pH extremes of these habitats often exceed the acid tolerance of type species and strains. Here, experimental evolution was used to test whether such organisms harbor additional thermoacidophilic capacity. Three distinct cell lines derived from a single type species were subjected to high temperature serial passage while culture acidity was gradually increased. A 178-fold increase in thermoacidophily was achieved after 29 increments of shifted culture pH resulting in growth at pH 0.8 and 80°C. These strains are named super acid resistant crenarchaeota (SARC). Mathematical modeling using growth parameters predicted the limits of acid resistance while genome and transcriptome resequencing provided insights into the underlying mechanisms responsible for evolved thermoacidophily. Transcriptomics of the evolved strains indicates that their unique phenotype may be due to an increased rate of membrane turnover under strong acid conditions.
2015-12-31 | GSE76423 | GEO
Project description:Extremely thermoacidophilic Crenarchaeota belonging to the family Sulfolobales flourish in hot acidic habitats that are strongly oxidizing. However, the pH extremes of these habitats often exceed the acid tolerance of type species and strains. Here, experimental evolution was used to test whether such organisms harbor additional thermoacidophilic capacity. Three distinct cell lines derived from a single type species were subjected to high temperature serial passage while culture acidity was gradually increased. A 178-fold increase in thermoacidophily was achieved after 29 increments of shifted culture pH resulting in growth at pH 0.8 and 80°C. These strains are named super acid resistant crenarchaeota (SARC). Mathematical modeling using growth parameters predicted the limits of acid resistance while genome and transcriptome resequencing provided insights into the underlying mechanisms responsible for evolved thermoacidophily. Transcriptomics of the evolved strains indicates that their unique phenotype may be due to an increased rate of membrane turnover under strong acid conditions. 6 Samples were analyzed: 2 replicate control samples [SULA] and 2 replicate experimental samples [SULC and SULB]
2015-12-31 | E-GEOD-76423 | biostudies-arrayexpress
Project description:Hydrogen served as a competitive inorganic energy source, impacting the CuFeS2 bioleaching efficiency of the extremely thermoacidophilic archaeon Metallosphaera sedula. Open reading frames encoding key terminal oxidase and electron transport chain components were triggered by CuFeS2. Evidence of heterotrophic metabolism was noted after extended periods of bioleaching, presumably related to cell lysis.
2010-03-15 | GSE20554 | GEO
Project description:Metallosphaera sedula strain:SARC-M1 Genome sequencing and assembly
| PRJNA290374 | ENA
Project description:Hydrogen served as a competitive inorganic energy source, impacting the CuFeS2 bioleaching efficiency of the extremely thermoacidophilic archaeon Metallosphaera sedula. Open reading frames encoding key terminal oxidase and electron transport chain components were triggered by CuFeS2. Evidence of heterotrophic metabolism was noted after extended periods of bioleaching, presumably related to cell lysis. One 3 slide loop for Mse cells includes 3 conditions: M. sedula inoculum prior to introduction to chalcopyrite (d0~day 0), M. sedula after 3 days on chalcopyrite (d3~day 3), and M. sedula after 9 days on chalcopyrite (d9~day 9). Half of an RNA sample for one condition (consisting of pools of RNA from multiple cultures) was labeled with Cy3 while the other half was labeled with Cy5. The two differently labeled samples were run on different slides. Each probe is spotted on each slide 5 times (5 spots/slide x 2 slides = 10 technical replicates per condition; spot intensities for all replicates on slide provided in associated raw data file).
2010-05-05 | E-GEOD-20554 | biostudies-arrayexpress
Project description:Abstract: The crenarchaeal order Sulfolobales collectively contains at least five major terminal oxidase complexes. Based on genome sequence information, all five complexes are found only in Metallosphaera sedula and Sulfolobus tokodaii, the two sequenced Sulfolobales capable of iron oxidization. While specific respiratory complexes in certain Sulfolobales have been characterized previously as proton pumps for maintaining intracellular pH and generating proton motive force (pmf), their contribution to sulfur and iron biooxidation has not been considered. For M. sedula growing in the presence of ferrous iron and reduced inorganic sulfur compounds (RISCs), global transcriptional analysis was used to track the response of specific genes associated with these complexes, as well as other known and putative respiratory electron transport chain elements. ORFs from all five terminal oxidase or bc1-like complexes were stimulated on one or more conditions tested. Components of the fox (Msed0467-0489) and soxNL-cbsABA (Msed0500-0505) terminal/quinol oxidase clusters were triggered by ferrous iron, while the soxABCDD' terminal oxidase cluster (Msed0285-0291) were induced by tetrathionate and S°. Chemolithotrophic electron transport elements, including a putative tetrathionate hydrolase (Msed0804), a novel polysulfide/sulfur/DMSO reductase-like complex (Msed0812-0818), and a novel heterodisulfide reductase-like complex (Msed1542-1550), were also stimulated by RISCs. Furthermore, several hypothetical proteins were found to have strong responses to ferrous iron or RISCs, suggesting additional candidates in iron or sulfur oxidation-related pathways. From this analysis, a comprehensive model for electron transport in M. sedula could be proposed as the basis for examining specific details of iron and sulfur oxidation in this bioleaching archaeon. 5-slide loop of Mse cells includes 5 conditions tested: yeast exact (Y), yeast extract + ferrous sulfate (YFS), yeast extract + potassium sulfate (YKS), yeast extract + potassium tetrathionate (YKT), and yeast extract + elemental sulfur (YS). Half of an RNA sample for one condition was labeled with Cy3 while the other half was labeled with Cy5. The two differently labeled samples were run on different slides. Each probe is spotted on each slide 5 times (5 replicates; spot intensities for all replicates on slide provided in associated raw data file).
2008-10-22 | E-GEOD-12044 | biostudies-arrayexpress
Project description:Gene expression profiles of Escherichia coli K-12 W3110 were compared as a function of steady-state external pH. Cultures were grown with aeration to an optical density at 600 nm of 0.3 in potassium-modified Luria-Bertani medium buffered at pH 5.0, 7.0, and 8.7. For each of the three pH conditions, cDNA from RNA of five independent cultures was hybridized to Affymetrix E. coli arrays. Analysis of variance with a significance level of 0.001 resulted in 98% power to detect genes showing a twofold difference in expression. Normalized expression indices were calculated for each gene and intergenic region (IG). Differential expression among the three pH classes was observed for 763 genes and 353 IGs. Hierarchical clustering yielded six well-defined clusters of pH profiles, designated Acid High (highest expression at pH 5.0), Acid Low (lowest expression at pH 5.0), Base High (highest at pH 8.7), Base Low (lowest at pH 8.7), Neutral High (highest at pH 7.0, lower in acid or base), and Neutral Low (lowest at pH 7.0, higher at both pH extremes). Flagellar and chemotaxis genes were repressed at pH 8.7 (Base Low cluster), where the cell's transmembrane proton potential is diminished by the maintenance of an inverted pH gradient. High pH also repressed the proton pumps cytochrome o (cyo) and NADH dehydrogenases I and II. By contrast, the proton-importing ATP synthase F1Fo and the microaerophilic cytochrome d (cyd), which minimizes proton export, were induced at pH 8.7. These observations are consistent with a model in which high pH represses synthesis of flagella, which expend proton motive force, while stepping up electron transport and ATPase components that keep protons inside the cell. Acid-induced genes, on the other hand, were coinduced by conditions associated with increased metabolic rate, such as oxidative stress. All six pH-dependent clusters included envelope and periplasmic proteins, which directly experience external pH. Overall, this study showed that (i) low pH accelerates acid consumption and proton export, while coinducing oxidative stress and heat shock regulons; (ii) high pH accelerates proton import, while repressing the energy-expensive flagellar and chemotaxis regulons; and (iii) pH differentially regulates a large number of periplasmic and envelope proteins. Keywords: Steady State
2006-03-23 | GSE4511 | GEO
Project description:Gene expression profiles of Escherichia coli K-12 W3110 were compared as a function of steady-state external pH. Cultures were grown with aeration to an optical density at 600 nm of 0.3 in potassium-modified Luria-Bertani medium buffered at pH 5.0, 7.0, and 8.7. For each of the three pH conditions, cDNA from RNA of five independent cultures was hybridized to Affymetrix E. coli arrays. Analysis of variance with a significance level of 0.001 resulted in 98% power to detect genes showing a twofold difference in expression. Normalized expression indices were calculated for each gene and intergenic region (IG). Differential expression among the three pH classes was observed for 763 genes and 353 IGs. Hierarchical clustering yielded six well-defined clusters of pH profiles, designated Acid High (highest expression at pH 5.0), Acid Low (lowest expression at pH 5.0), Base High (highest at pH 8.7), Base Low (lowest at pH 8.7), Neutral High (highest at pH 7.0, lower in acid or base), and Neutral Low (lowest at pH 7.0, higher at both pH extremes). Flagellar and chemotaxis genes were repressed at pH 8.7 (Base Low cluster), where the cell's transmembrane proton potential is diminished by the maintenance of an inverted pH gradient. High pH also repressed the proton pumps cytochrome o (cyo) and NADH dehydrogenases I and II. By contrast, the proton-importing ATP synthase F1Fo and the microaerophilic cytochrome d (cyd), which minimizes proton export, were induced at pH 8.7. These observations are consistent with a model in which high pH represses synthesis of flagella, which expend proton motive force, while stepping up electron transport and ATPase components that keep protons inside the cell. Acid-induced genes, on the other hand, were coinduced by conditions associated with increased metabolic rate, such as oxidative stress. All six pH-dependent clusters included envelope and periplasmic proteins, which directly experience external pH. Overall, this study showed that (i) low pH accelerates acid consumption and proton export, while coinducing oxidative stress and heat shock regulons; (ii) high pH accelerates proton import, while repressing the energy-expensive flagellar and chemotaxis regulons; and (iii) pH differentially regulates a large number of periplasmic and envelope proteins. Experiment Overall Design: Gene expression profiles of Escherichia coli K-12 W3110 were compared as a function of steady-state external pH. Overnight cultures were diluted 1:1000 in potassium-modified Luria-Bertani medium (LBK) buffered with 50 mM HOMOPIPES at pH 5.0, pH 7.0, and pH 8.7. Bacteria were cultured in baffled flasks (less than 10% volume filled) with rotation at 240 rpm, incubated at 37°C to an optical density at 600 nm of 0.3. For each of the three pH conditions, RNA was isolated from five independent cultures. Labeled cDNA was hybridized to Affymetrix antisense arrays according to standard procedures. To analyze the expression levels, Dchip software was used to generate model-based expression indices normalized to sample pH 7 replicate 1. ANOVA was used to identify genes with sitnificant expression differences among the three pH classes (p = 0.001). For genes showing significant differences, the Log2 expression ratios were determined for each pair of pH classes, and significance was determined by Tukey's test (p = 0.001).
2007-09-21 | E-GEOD-4511 | biostudies-arrayexpress