scholarly journals Nanoscale Tungsten-Microbial Interface of the Metal Immobilizing Thermoacidophilic Archaeon Metallosphaera sedula Cultivated With Tungsten Polyoxometalate

2019 ◽  
Vol 10 ◽  
Author(s):  
Tetyana Milojevic ◽  
Mihaela Albu ◽  
Amir Blazevic ◽  
Nadiia Gumerova ◽  
Lukas Konrad ◽  
...  
2014 ◽  
Vol 196 (20) ◽  
pp. 3562-3570 ◽  
Author(s):  
S. McCarthy ◽  
C. Ai ◽  
G. Wheaton ◽  
R. Tevatia ◽  
V. Eckrich ◽  
...  

Archaea ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Matías Rivero ◽  
Constanza Torres-Paris ◽  
Rodrigo Muñoz ◽  
Ricardo Cabrera ◽  
Claudio A. Navarro ◽  
...  

Polyphosphates (PolyP) are linear polymers of orthophosphate residues that have been proposed to participate in metal resistance in bacteria and archaea. In addition of having a CopA/CopB copper efflux system, the thermoacidophilic archaeonMetallosphaera sedulacontains electron-dense PolyP-like granules and a putative exopolyphosphatase (PPXMsed,Msed_0891) and four presumedpho84-like phosphate transporters (Msed_0846,Msed_0866,Msed_1094, andMsed_1512) encoded in its genome. In the present report, the existence of a possible PolyP-based copper-resistance mechanism inM. sedulaDSM 5348Twas evaluated.M. sedulaDSM 5348Taccumulated high levels of phosphorous in the form of granules, and its growth was affected in the presence of 16 mM copper. PolyP levels were highly reduced after the archaeon was subjected to an 8 mM CuSO4shift. PPXMsedwas purified, and the enzyme was found to hydrolyze PolyPin vitro. Essential residues for catalysis of PPXMsedwere E111 and E113 as shown by a site-directed mutagenesis of the implied residues. Furthermore,M. sedula ppx,pho84-like, andcopTMAgenes were upregulated upon copper exposure, as determined by qRT-PCR analysis. The results obtained support the existence of a PolyP-dependent copper-resistance system that may be of great importance in the adaptation of this thermoacidophilic archaeon to its harsh environment.


1989 ◽  
Vol 12 (1) ◽  
pp. 38-47 ◽  
Author(s):  
Gertrud Huber ◽  
Carola Spinnler ◽  
Agata Gambacorta ◽  
Karl O. Stetter

2016 ◽  
Vol 82 (15) ◽  
pp. 4613-4627 ◽  
Author(s):  
Garrett H. Wheaton ◽  
Arpan Mukherjee ◽  
Robert M. Kelly

ABSTRACTThe extremely thermoacidophilic archaeonMetallosphaera sedulamobilizes metals by novel membrane-associated oxidase clusters and, consequently, requires metal resistance strategies. This issue was examined by “shocking”M. sedulawith representative metals (Co2+, Cu2+, Ni2+, UO22+, Zn2+) at inhibitory and subinhibitory levels. Collectively, one-quarter of the genome (554 open reading frames [ORFs]) responded to inhibitory levels, and two-thirds (354) of the ORFs were responsive to a single metal. Cu2+(259 ORFs, 106 Cu2+-specific ORFs) and Zn2+(262 ORFs, 131 Zn2+-specific ORFs) triggered the largest responses, followed by UO22+(187 ORFs, 91 UO22+-specific ORFs), Ni2+(93 ORFs, 25 Ni2+-specific ORFs), and Co2+(61 ORFs, 1 Co2+-specific ORF). While one-third of the metal-responsive ORFs are annotated as encoding hypothetical proteins, metal challenge also impacted ORFs responsible for identifiable processes related to the cell cycle, DNA repair, and oxidative stress. Surprisingly, there were only 30 ORFs that responded to at least four metals, and 10 of these responded to all five metals. This core transcriptome indicated induction of Fe-S cluster assembly (Msed_1656-Msed_1657), tungsten/molybdenum transport (Msed_1780-Msed_1781), and decreased central metabolism. Not surprisingly, a metal-translocating P-type ATPase (Msed_0490) associated with a copper resistance system (Cop) was upregulated in response to Cu2+(6-fold) but also in response to UO22+(4-fold) and Zn2+(9-fold). Cu2+challenge uniquely induced assimilatory sulfur metabolism for cysteine biosynthesis, suggesting a role for this amino acid in Cu2+resistance or issues in sulfur metabolism. The results indicate thatM. sedulaemploys a range of physiological and biochemical responses to metal challenge, many of which are specific to a single metal and involve proteins with yet unassigned or definitive functions.IMPORTANCEThe mechanisms by which extremely thermoacidophilic archaea resist and are negatively impacted by metals encountered in their natural environments are important to understand so that technologies such as bioleaching, which leverage microbially based conversion of insoluble metal sulfides to soluble species, can be improved. Transcriptomic analysis of the cellular response to metal challenge provided both global and specific insights into how these novel microorganisms negotiate metal toxicity in natural and technological settings. As genetics tools are further developed and implemented for extreme thermoacidophiles, information about metal toxicity and resistance can be leveraged to create metabolically engineered strains with improved bioleaching characteristics.


2014 ◽  
Vol 80 (8) ◽  
pp. 2536-2545 ◽  
Author(s):  
Aaron B. Hawkins ◽  
Michael W. W. Adams ◽  
Robert M. Kelly

ABSTRACTThe extremely thermoacidophilic archaeonMetallosphaera sedula(optimum growth temperature, 73°C, pH 2.0) grows chemolithoautotrophically on metal sulfides or molecular hydrogen by employing the 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) carbon fixation cycle. This cycle adds two CO2molecules to acetyl coenzyme A (acetyl-CoA) to generate 4HB, which is then rearranged and cleaved to form two acetyl-CoA molecules. Previous metabolic flux analysis showed that two-thirds of central carbon precursor molecules are derived from succinyl-CoA, which is oxidized to malate and oxaloacetate. The remaining one-third is apparently derived from acetyl-CoA. As such, the steps beyond succinyl-CoA are essential for completing the carbon fixation cycle and for anapleurosis of acetyl-CoA. Here, the final four enzymes of the 3HP/4HB cycle, 4-hydroxybutyrate-CoA ligase (AMP forming) (Msed_0406), 4-hydroxybutyryl-CoA dehydratase (Msed_1321), crotonyl-CoA hydratase/(S)-3-hydroxybutyryl-CoA dehydrogenase (Msed_0399), and acetoacetyl-CoA β-ketothiolase (Msed_0656), were produced recombinantly inEscherichia coli, combinedin vitro, and shown to convert 4HB to acetyl-CoA. Metabolic pathways connecting CO2fixation and central metabolism were examined using a gas-intensive bioreactor system in whichM. sedulawas grown under autotrophic (CO2-limited) and heterotrophic conditions. Transcriptomic analysis revealed the importance of the 3HP/4HB pathway in supplying acetyl-CoA to anabolic pathways generating intermediates inM. sedulametabolism. The results indicated that flux between the succinate and acetyl-CoA branches in the 3HP/4HB pathway is governed by 4-hydroxybutyrate-CoA ligase, possibly regulated posttranslationally by the protein acetyltransferase (Pat)/Sir2-dependent system. Taken together, this work confirms the final four steps of the 3HP/4HB pathway, thereby providing the framework for examining connections between CO2fixation and central metabolism inM. sedula.


2014 ◽  
Vol 81 (5) ◽  
pp. 1700-1707 ◽  
Author(s):  
Julia Otte ◽  
Achim Mall ◽  
Daniel M. Schubert ◽  
Martin Könneke ◽  
Ivan A. Berg

ABSTRACTThe recently described ammonia-oxidizing archaea of the phylumThaumarchaeotaare highly abundant in marine, geothermal, and terrestrial environments. All characterized representatives of this phylum are aerobic chemolithoautotrophic ammonia oxidizers assimilating inorganic carbon via a recently described thaumarchaeal version of the 3-hydroxypropionate/4-hydroxybutyrate cycle. Although some genes coding for the enzymes of this cycle have been identified in the genomes ofThaumarchaeota, many other genes of the cycle are not homologous to the characterized enzymes from other species and can therefore not be identified bioinformatically. Here we report the identification and characterization of malonic semialdehyde reductase Nmar_1110 in the cultured marine thaumarchaeonNitrosopumilus maritimus. This enzyme, which catalyzes the reduction of malonic semialdehyde with NAD(P)H to 3-hydroxypropionate, belongs to the family of iron-containing alcohol dehydrogenases and is not homologous to malonic semialdehyde reductases fromChloroflexus aurantiacusandMetallosphaera sedula. It is highly specific to malonic semialdehyde (Km, 0.11 mM;Vmax, 86.9 μmol min−1mg−1of protein) and exhibits only low activity with succinic semialdehyde (Km, 4.26 mM;Vmax, 18.5 μmol min−1mg−1of protein). Homologues ofN. maritimusmalonic semialdehyde reductase can be found in the genomes of allThaumarchaeotasequenced so far and form a well-defined cluster in the phylogenetic tree of iron-containing alcohol dehydrogenases. We conclude that malonic semialdehyde reductase can be regarded as a characteristic enzyme for the thaumarchaeal version of the 3-hydroxypropionate/4-hydroxybutyrate cycle.


2012 ◽  
Vol 194 (24) ◽  
pp. 6856-6863 ◽  
Author(s):  
Y. Maezato ◽  
T. Johnson ◽  
S. McCarthy ◽  
K. Dana ◽  
P. Blum

2007 ◽  
Vol 20-21 ◽  
pp. 350-353 ◽  
Author(s):  
Katja Etzel ◽  
Harald Huber ◽  
Reinhard Rachel ◽  
Gottfried Schmalz ◽  
Michael Thomm ◽  
...  

To enhance our understanding of effects of microbially mediated pyrite dissolution and the influence parameters such as varied metabolism and crystallographic orientation of pyrite surfaces some dissolution experiments were performed. Microbial etching experiments on pyrite surfaces of different orientation, including {111} and {210} were devised. The experiments were performed using two strains of thermophilic Archaea (Sulfolobus metallicus, Metallosphaera sedula). Epifluorescence microscopy observations showed that the strains attach to the mineral surface. Studies with Scanning Electron Microscopy (SEM) showed cell attachment and etching effects after one week of incubation. Surface alteration produced structures following crystallographic orientation up to several 10 μm in size. For all incubated pyrite samples it became apparent that surface alteration was more pronounced with M. sedula than with S. metallicus.


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