Isolation and characterization of arsenic resistant <i>Geobacillus kaustophilus</i> strain from geothermal soils

Cuebas, Mariola; Sannino, David R.; Bini, Elisabetta

doi:10.1002/jobm.201000314

Cited by 27 publications

(21 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Members of this genus have been isolated from a wide range of environments, including temperate soils, as well as natural and artificial hot environments (4,21,35). This implies great environmental adaptability, which is supported by the remarkable properties of isolated Geobacillus species, such as ethanol tolerance (10), arsenate resistance (7), and the ability to degrade long-chain alkanes (35) and herbicides (21). Because of these properties, along with their thermophilicity and catabolic versatility, Geobacillus spp.…”

mentioning

confidence: 99%

Counterselection System for Geobacillus kaustophilus HTA426 through Disruption of pyrF and pyrR

Suzuki

Murakami

Yoshida

2012

Appl Environ Microbiol

View full text Add to dashboard Cite

bCounterselection systems facilitate marker-free genetic modifications in microbes by enabling positive selections for both the introduction of a marker gene into the microbe and elimination of the marker from the microbe. Here we report a counterselection system for Geobacillus kaustophilus HTA426, established through simultaneous disruption of the pyrF and pyrR genes. The pyrF gene, essential for pyrimidine biosynthesis and metabolization of 5-fluoroorotic acid (5-FOA) to toxic metabolites, was disrupted by homologous recombination. The resultant MK54 strain (⌬pyrF) was auxotrophic for uracil and resistant to 5-FOA. MK54 complemented with pyrF was prototrophic for uracil but insensitive to 5-FOA in the presence of uracil. To confer 5-FOA sensitivity, the pyrR gene encoding an attenuator to repress pyrimidine biosynthesis by sensing uracil derivatives was disrupted. The resultant MK72 strain (⌬pyrF ⌬pyrR) was auxotrophic for uracil and resistant to 5-FOA. MK72 complemented with pyrF was prototrophic for uracil and 5-FOA sensitive even in the presence of uracil. The results suggested that pyrF could serve as a counterselection marker in MK72, which was demonstrated by efficient marker-free integrations of heterologous ␤-galactosidase and ␣-amylase genes. The integrated genes were functionally expressed in G. kaustophilus and conferred new functions on the thermophile. This report describes the first establishment of a pyrF-based counterselection system in a Bacillus-related bacterium, along with the first demonstration of homologous recombination and heterologous gene expression in G. kaustophilus. Our results also suggest a new strategy for establishment of counterselection systems.

show abstract

mentioning

confidence: 99%

Counterselection System for Geobacillus kaustophilus HTA426 through Disruption of pyrF and pyrR

Suzuki

Murakami

Yoshida

2012

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…These mechanisms, such as efflux, intra-or extracellular precipitation, and enzyme-mediated transformations, control intracellular concentrations of heavy metal ions that may be inhibitory to physiological functions and form nonspecific complex compounds in the cell (28). While much of our existing knowledge of these resistance mechanisms has arisen from research motivated by metal contamination from the perspective of human and environmental health (5,9,11,26,29), a cosmopolitan distribution of metal-resistant microorganisms inhabiting environments that are enriched with metals of geological origin suggests evolution of metal ion resistance prior to industrial release of metal contaminants (2,13,50).…”

mentioning

confidence: 99%

Mercury Resistance and Mercuric Reductase Activities and Expression among Chemotrophic Thermophilic Aquificae

Freedman

Zhu

Barkay

2012

Appl Environ Microbiol

View full text Add to dashboard Cite

ABSTRACTMercury (Hg) resistance (mer) by the reduction of mercuric to elemental Hg is broadly distributed among theBacteriaandArchaeaand plays an important role in Hg detoxification and biogeochemical cycling. MerA is the protein subunit of the homodimeric mercuric reductase (MR) enzyme, the central function of themersystem. MerA sequences in the phylumAquificaeform the deepest-branching lineage in Bayesian phylogenetic reconstructions of all known MerA homologs. We therefore hypothesized that themerAhomologs in two thermophilicAquificae,Hydrogenobaculumsp. strain Y04AAS1 (AAS1) andHydrogenivirgasp. strain 128-5-R1-1 (R1-1), specified Hg resistance. Results supported this hypothesis, because strains AAS1 and R1-1 (i) were resistant to >10 μM Hg(II), (ii) transformed Hg(II) to Hg(0) during cellular growth, and (iii) possessed Hg-dependent NAD(P)H oxidation activities in crude cell extracts that were optimal at temperatures corresponding with the strains' optimal growth temperatures, 55°C for AAS1 and 70°C for R1-1. While these characteristics all conformed with themersystem paradigm, expression of theAquificaemeroperons was not induced by exposure to Hg(II) as indicated by unity ratios ofmerAtranscripts, normalized togyrAtranscripts for hydrogen-grown AAS1 cultures, and by similar MR specific activities in thiosulfate-grown cultures with and without Hg(II). The Hg(II)-independent expression ofmerin the deepest-branching lineage of MerA from bacteria whose natural habitats are Hg-rich geothermal environments suggests that regulated expression ofmerwas a later innovation likely in environments where microorganisms were intermittently exposed to toxic concentrations of Hg.

show abstract

“…Nevertheless, both strains are highly resistant to arsenate. Geobacillus kaustophilus HTA426 [68], Bacillus cereus strain AG27 [69], and B . subtilis strain B-1232 [70], for example, exhibited MICs of 80 mM, 40 mM, and 110 mM of arsenate, respectively.…”

Section: Resultsmentioning

confidence: 99%

Complete genome sequence and metabolic potential of the quinaldine-degrading bacterium Arthrobacter sp. Rue61a

et al. 2012

View full text Add to dashboard Cite

BackgroundBacteria of the genus Arthrobacter are ubiquitous in soil environments and can be considered as true survivalists. Arthrobacter sp. strain Rue61a is an isolate from sewage sludge able to utilize quinaldine (2-methylquinoline) as sole carbon and energy source. The genome provides insight into the molecular basis of the versatility and robustness of this environmental Arthrobacter strain.ResultsThe genome of Arthrobacter sp. Rue61a consists of a single circular chromosome of 4,736,495 bp with an average G + C content of 62.32%, the circular 231,551-bp plasmid pARUE232, and the linear 112,992-bp plasmid pARUE113 that was already published. Plasmid pARUE232 is proposed to contribute to the resistance of Arthrobacter sp. Rue61a to arsenate and Pb2+, whereas the linear plasmid confers the ability to convert quinaldine to anthranilate. Remarkably, degradation of anthranilate exclusively proceeds via a CoA-thioester pathway. Apart from quinaldine utilization, strain Rue61a has a limited set of aromatic degradation pathways, enabling the utilization of 4-hydroxy-substituted aromatic carboxylic acids, which are characteristic products of lignin depolymerization, via ortho cleavage of protocatechuate. However, 4-hydroxyphenylacetate degradation likely proceeds via meta cleavage of homoprotocatechuate. The genome of strain Rue61a contains numerous genes associated with osmoprotection, and a high number of genes coding for transporters. It encodes a broad spectrum of enzymes for the uptake and utilization of various sugars and organic nitrogen compounds. A. aurescens TC-1 is the closest sequenced relative of strain Rue61a.ConclusionsThe genome of Arthrobacter sp. Rue61a reflects the saprophytic lifestyle and nutritional versatility of the organism and a strong adaptive potential to environmental stress. The circular plasmid pARUE232 and the linear plasmid pARUE113 contribute to heavy metal resistance and to the ability to degrade quinaldine, respectively.

show abstract

Isolation and characterization of arsenic resistant Geobacillus kaustophilus strain from geothermal soils

Cited by 27 publications

References 29 publications

Counterselection System for Geobacillus kaustophilus HTA426 through Disruption of pyrF and pyrR

Counterselection System for Geobacillus kaustophilus HTA426 through Disruption of pyrF and pyrR

Mercury Resistance and Mercuric Reductase Activities and Expression among Chemotrophic Thermophilic Aquificae

Complete genome sequence and metabolic potential of the quinaldine-degrading bacterium Arthrobacter sp. Rue61a

Contact Info

Product

Resources

About