Molecular insight into extreme copper resistance in the extremophilic archaeon ‘Ferroplasma acidarmanus’ Fer1

Microbiology ◽  
2005 ◽  
Vol 151 (8) ◽  
pp. 2637-2646 ◽  
Author(s):  
Craig Baker-Austin ◽  
Mark Dopson ◽  
Margaret Wexler ◽  
R. Gary Sawers ◽  
Philip L. Bond
Keyword(s):  
Metal Binding ◽  
Stress Proteins ◽  
Mine Drainage ◽  
Copper Resistance ◽  
Genes Encoding ◽  
Ferroplasma Acidarmanus ◽  
Copper Contaminated ◽  
P Type ◽  
Growth Experiments ◽  
Insight Into

‘Ferroplasma acidarmanus’ strain Fer1 is an extremely acidophilic archaeon involved in the genesis of acid mine drainage, and was isolated from copper-contaminated mine solutions at Iron Mountain, CA, USA. Here, the initial proteomic and molecular investigation of Cu2+ resistance in this archaeon is presented. Analysis of Cu2+ toxicity via batch growth experiments and inhibition of oxygen uptake in the presence of ferrous iron demonstrated that Fer1 can grow and respire in the presence of 20 g Cu2+ l−1. The Fer1 copper resistance (cop) loci [originally detected by Ettema, T. J. G., Huynen, M. A., de Vos, W. M. & van der Oost, J. Trends Biochem Sci 28, 170–173 (2003)] include genes encoding a putative transcriptional regulator (copY), a putative metal-binding chaperone (copZ) and a putative copper-transporting P-type ATPase (copB). Transcription analyses demonstrated that copZ and copB are co-transcribed, and transcript levels were increased significantly in response to exposure to high levels of Cu2+, suggesting that the transport system is operating for copper efflux. Proteomic analysis of Fer1 cells exposed to Cu2+ revealed the induction of stress proteins associated with protein folding and DNA repair (including RadA, thermosome and DnaK homologues), suggesting that ‘Ferroplasma acidarmanus’ Fer1 uses multiple mechanisms for resistance to high levels of copper.

scholarly journals Genes Conferring Copper Resistance inSinorhizobium melilotiCCNWSX0020 Also Promote the Growth ofMedicago lupulinain Copper-Contaminated Soil

2014 ◽  
Vol 80 (6) ◽  
pp. 1961-1971 ◽  
Author(s):  
Zhefei Li ◽  
Zhanqiang Ma ◽  
Xiuli Hao ◽  
Christopher Rensing ◽  
Gehong Wei
Keyword(s):  
Host Plant ◽  
Contaminated Soil ◽  
Copper Resistance ◽  
Inverse Pcr ◽  
Copper Accumulation ◽  
Wild Type ◽  
Transposon Insertion ◽  
Metal Binding Domain ◽  
Copper Contaminated ◽  
P Type

ABSTRACTSinorhizobium melilotiCCNWSX0020, isolated from root nodules ofMedicago lupulinagrowing in gold mine tailings in the northwest of China, displayed both copper resistance and growth promotion of leguminous plants in copper-contaminated soil. Nevertheless, the genetic and biochemical mechanisms responsible for copper resistance inS. melilotiCCNWSX0020 remained uncharacterized. To investigate genes involved in copper resistance, anS. melilotiCCNWSX0020 Tn5insertion library of 14,000 mutants was created. Five copper-sensitive mutants, named SXa-1, SXa-2, SXc-1, SXc-2, and SXn, were isolated, and the disrupted regions involved were identified by inverse PCR and subsequent sequencing. Both SXa-1 and SXa-2 carried a transposon insertion inlpxXL(SM0020_18047), encoding the LpxXL C-28 acyltransferase; SXc-1 and SXc-2 carried a transposon insertion inmerR(SM0020_29390), encoding the regulatory activator; SXn contained a transposon insertion inomp(SM0020_18792), encoding a hypothetical outer membrane protein. The results of reverse transcriptase PCR (RT-PCR) combined with transposon gene disruptions revealed thatSM0020_05862, encoding an unusual P-type ATPase, was regulated by the MerR protein. Analysis of the genome sequence showed that this P-type ATPase did not contain an N-terminal metal-binding domain or a CPC motif but rather TPCP compared with CopA fromEscherichia coli. Pot experiments were carried out to determine whether growth and copper accumulation of the host plantM. lupulinawere affected in the presence of the wild type or the different mutants. Soil samples were subjected to three levels of copper contamination, namely, the uncontaminated control and 47.36 and 142.08 mg/kg, and three replicates were conducted for each treatment. The results showed that the wild-typeS. melilotiCCNWSX0020 enabled the host plant to grow better and accumulate copper ions. The plant dry weight and copper content ofM. lupulinainoculated with the 5 copper-sensitive mutants significantly decreased in the presence of CuSO4.

scholarly journals Resistance to Ag(I) Cations in Bacteria: Environments, Genes and Proteins

1999 ◽  
Vol 6 (4-5) ◽  
pp. 315-320 ◽  
Author(s):  
Simon Silver ◽  
Amit Gupta ◽  
Kazuaki Matsui ◽  
Jeng-Fan Lo
Keyword(s):  
Dna Sequencing ◽  
Dna Sequences ◽  
Metal Binding ◽  
Bacterial Resistance ◽  
Copper Resistance ◽  
Resistant Bacteria ◽  
Amino Terminal ◽  
Two Component Systems ◽  
P Type

Bacterial resistance to Ag(I) has been reported periodically with isolates from many environments where toxic levels of silver might be expected to occur, but initial reports were limited to the occurrence of resistant bacteria. The availability of silver-resistance conferring DNA sequences now allow genetic and mechanistic studies that had basically been missing. The genes determining Ag(I) resistance were sequenced from a plasmid found in a burn ward isolate. The 14.2 kb determinant contains seven recognized genes, arranged in three mRNA transcriptional units. The silE gene determines an extracellular (periplasmic space) metal-binding protein of 123 amino acids, including ten histidine residues implicated in Ag(I) binding. SilE is homologous to PcoE, of copper resistance. The next two genes, silR and silS, determine a two protein, histidine-kinase membrane sensor and aspartyl phosphate transcriptional responder, similar to other two component systems such as CzcR and CzcS (for cadmium, zinc and cobalt resistance) and PcoR and PcoS (for copper resistance). The remaining four genes, silCBAP, are co-transcribed and appear to determine Ag+ efflux, with SilCBA homologous to CzcCBA, a three component cation/proton antiporter, and SilP a novel P-type ATPase with a amino-terminal histidine-rich cation-specificity region. The effects of increasing Ag+ concentrations and growth medium halides (Cl-, Br- and I-) have been characterized, with lower Cl- concentrations facilitating resistance and higher concentrations toxicity. The properties of this unique Ag(I)-binding SilE protein are being characterized. Sequences similar to the silver-resistance DNA are being characterized by Southern blot DNA/DNA hybridization, PCR in vitro DNA synthesis and DNA sequencing. More than 25 additional closely related sequences have been identified in bacteria from diverse sources. Initial DNA sequencing results shows approximately 5-20% differences in DNA sequences.

Localization of metallothionein, heat shock protein (Hsp70), and superoxide dismutase expression in Hemidiaptomus roubaui (Copepoda, Crustacea) exposed to cadmium and heat stress

2007 ◽  
Vol 85 (3) ◽  
pp. 362-371 ◽  
Author(s):  
Martine Liberge ◽  
Roxane-M. Barthélémy
Keyword(s):  
Superoxide Dismutase ◽  
Heat Stress ◽  
Heat Shock ◽  
Metal Binding ◽  
Stress Proteins ◽  
Reproductive Function ◽  
Cadmium Stress ◽  
Specific Distribution ◽  
Freshwater Crustacean ◽  
Shock Proteins

Immunohistochemical methods were applied in the present study to investigate the expression of stress proteins such as metallothioneins (MT), which are metal-binding proteins, and heat shock proteins (Hsp70), as well as an antioxidant enzyme (superoxide dismutase, SOD), in the freshwater crustacean copepod Hemidiaptomus roubaui (Richard, 1888) exposed to cadmium or heat stress. The results show a tissue-specific distribution of MT-like protein after cadmium exposure in the brain and in the nerve cord. Cadmium stress did not provoke inducible Hsp70 or SOD expression. Unlike cadmium, heat stress induced the expression of Hsp70 and SOD in the shell glands, a structure involved in the reproductive function, and more particularly in the formation of the diapause egg envelope. MT expression is not induced in animals exposed to heat stress.

scholarly journals Reconstitution of the Human tRNA Splicing Endonuclease Complex: insight into the regulation of pre-tRNA cleavage

2019 ◽  
Author(s):  
Cassandra K. Hayne ◽  
Casey A. Schmidt ◽  
A. Gregory Matera ◽  
Robin E. Stanley
Keyword(s):  
Animal Cells ◽  
Trna Splicing ◽  
Polynucleotide Kinase ◽  
Genes Encoding ◽  
Intron Removal ◽  
And Function ◽  
Insight Into ◽  
Negative Modulator

ABSTRACTThe splicing of tRNA introns is a critical step in pre-tRNA maturation. In archaea and eukaryotes, tRNA intron removal is catalyzed by the tRNA splicing endonuclease (TSEN) complex. Eukaryotic TSEN is comprised of four core subunits (TSEN54, TSEN2, TSEN34, and TSEN15). The human TSEN complex additionally co-purifies with the polynucleotide kinase CLP1; however, CLP1’s role in tRNA splicing remains unclear. Mutations in genes encoding all four TSEN subunits, as well as CLP1, are known to cause neurodegenerative disorders, yet the mechanisms underlying the pathogenesis of these disorders are unknown. Here, we developed a recombinant system that produces active TSEN complex. Co-expression of all four TSEN subunits is required for efficient formation and function of the complex. We show that human CLP1 associates with the active TSEN complex, but is not required for tRNA intron cleavage in vitro. Moreover, RNAi knockdown of the Drosophila CLP1 orthologue, cbc, promotes biogenesis of mature tRNAs and circularized tRNA introns (tricRNAs) in vivo. Collectively, these and other findings suggest that CLP1/cbc plays a regulatory role in tRNA splicing by serving as a negative modulator of the direct tRNA ligation pathway in animal cells.

scholarly journals Analyzing transport properties of p-type Mg2Si–Mg2Sn solid solutions: optimization of thermoelectric performance and insight into the electronic band structure

2019 ◽  
Vol 7 (3) ◽  
pp. 1045-1054 ◽  
Author(s):  
Hasbuna Kamila ◽  
Prashant Sahu ◽  
Aryan Sankhla ◽  
Mohammad Yasseri ◽  
Hoang-Ngan Pham ◽  
...  
Keyword(s):  
Band Structure ◽  
Transport Properties ◽  
Carrier Concentration ◽  
Solid Solutions ◽  
Figure Of Merit ◽  
Electronic Band Structure ◽  
Thermoelectric Performance ◽  
Electronic Band ◽  
P Type ◽  
Insight Into

Figure of merit zT mapping of p-Mg2Si1−xSnx with respect to carrier concentration.

scholarly journals The Role of the CopA Copper Efflux System in Acinetobacter baumannii Virulence

2019 ◽  
Vol 20 (3) ◽  
pp. 575 ◽  
Author(s):  
Saleh Alquethamy ◽  
Marjan Khorvash ◽  
Victoria Pederick ◽  
Jonathan Whittall ◽  
James Paton ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Copper Toxicity ◽  
In Silico Analysis ◽  
Opportunistic Pathogen ◽  
Copper Resistance ◽  
Copper Stress ◽  
Causative Agents ◽  
High Level ◽  
P Type

Acinetobacter baumannii has emerged as one of the leading causative agents of nosocomial infections. Due to its high level of intrinsic and adapted antibiotic resistance, treatment failure rates are high, which allows this opportunistic pathogen to thrive during infection in immune-compromised patients. A. baumannii can cause infections within a broad range of host niches, with pneumonia and bacteraemia being associated with the greatest levels of morbidity and mortality. Although its resistance to antibiotics is widely studied, our understanding of the mechanisms required for dealing with environmental stresses related to virulence and hospital persistence, such as copper toxicity, is limited. Here, we performed an in silico analysis of the A. baumannii copper resistome, examining its regulation under copper stress. Using comparative analyses of bacterial P-type ATPases, we propose that A. baumannii encodes a member of a novel subgroup of P1B-1 ATPases. Analyses of three putative inner membrane copper efflux systems identified the P1B-1 ATPase CopA as the primary mediator of cytoplasmic copper resistance in A. baumannii. Using a murine model of A. baumannii pneumonia, we reveal that CopA contributes to the virulence of A. baumannii. Collectively, this study advances our understanding of how A. baumannii deals with environmental copper toxicity, and it provides novel insights into how A. baumannii combats adversities encountered as part of the host immune defence.

scholarly journals Evidence for Involvement of at Least Six Proteins in Adaptation of Lactobacillus sakei to Cold Temperatures and Addition of NaCl

2004 ◽  
Vol 70 (12) ◽  
pp. 7260-7268 ◽  
Author(s):  
Anika Marceau ◽  
Monique Zagorec ◽  
Stéphane Chaillou ◽  
Thérèse Méra ◽  
Marie-Christine Champomier-Vergès
Keyword(s):  
Stationary Phase ◽  
Stress Proteins ◽  
Environmental Changes ◽  
Gene Clusters ◽  
Lactobacillus Sakei ◽  
Fresh Meat ◽  
Cold Temperatures ◽  
Natural Flora ◽  
Insight Into

ABSTRACT Lactobacillus sakei is a lactic acid bacterium widely represented in the natural flora of fresh meat. The aim of this study was to analyze the differences in protein expression during environmental changes encountered during technological processes in which L. sakei is involved in order to gain insight into the ability of this species to grow and survive in such environments. Using two-dimensional electrophoresis, we observed significant variation of a set of 21 proteins in cells grown at 4°C or in the presence of 4% NaCl. Six proteins could be identified by determination of their N-terminal sequences, and the corresponding gene clusters were studied. Two proteins belong to carbon metabolic pathways, and four can be clustered as general stress proteins. A phenotype was observed at low temperature for five of the six mutants constructed for these genes. The survival of four mutants during stationary phase at 4°C was affected, and surprisingly, one mutant showed enhanced survival during stationary phase at low temperatures.

Signals regulating trafficking of Menkes (MNK; ATP7A) copper-translocating P-type ATPase in polarized MDCK cells

2004 ◽  
Vol 287 (5) ◽  
pp. C1463-C1471 ◽  
Author(s):  
M. Greenough ◽  
L. Pase ◽  
I. Voskoboinik ◽  
M. J. Petris ◽  
A. Wilson O'Brien ◽  
...  
Keyword(s):  
Metal Binding ◽  
Laser Scanning ◽  
Mdck Cells ◽  
Laser Scanning Microscopy ◽  
Site Directed Mutagenesis ◽  
Confocal Laser ◽  
Molecular Evidence ◽  
Copper Absorption ◽  
P Type

The Menkes protein (MNK; ATP7A) functions as a transmembrane copper-translocating P-type ATPase and plays a vital role in systemic copper absorption in the gut and copper reabsorption in the kidney. Polarized epithelial cells such as Madin-Darby canine kidney (MDCK) cells are a physiologically relevant model for systemic copper absorption and reabsorption in vivo. In this study, cultured MDCK cells were used to characterize MNK trafficking and enabled the identification of signaling motifs required to target the protein to specific membranes. Using confocal laser scanning microscopy and surface biotinylation we demonstrate that MNK relocalizes from the Golgi to the basolateral (BL) membrane under elevated copper conditions. As previously shown in nonpolarized cells, the metal binding sites in the NH2-terminal domain of MNK were found to be required for copper-regulated trafficking from the Golgi to the plasma membrane. These data provide molecular evidence that is consistent with the presumed role of this protein in systemic copper absorption in the gut and reabsorption in the kidney. Using site-directed mutagenesis, we identified a dileucine motif proximal to the COOH terminus of MNK that was critical for correctly targeting the protein to the BL membrane and a putative PDZ target motif that was required for localization at the BL membrane in elevated copper.

Experiments and Entrepreneurship in Developing Countries

2019 ◽  
Vol 11 (1) ◽  
pp. 225-248 ◽  
Author(s):  
Simon Quinn ◽  
Christopher Woodruff
Keyword(s):  
Developing Countries ◽  
Labor Markets ◽  
Small Firms ◽  
Firm Growth ◽  
Small Enterprises ◽  
Skilled Workers ◽  
Individual Decision ◽  
Managerial Training ◽  
Growth Experiments ◽  
Insight Into

We discuss the value of experiments in illuminating constraints on the growth of firms in developing countries. Experiments have provided insight into both the value and the difficulty of alleviating capital constraints in small firms. They suggest that urban, low-skilled labor markets appear to work reasonably well for firms, although there is a suggestion that frictions in markets for skilled workers may have more effect on firms. While observational data suggest that managerial training is important, experiments have shown that the traditional methods of delivering this training to small enterprises, at least, are not effective. Finally, while most work has focused on alleviating supply constraints, recent experiments have shown that positive demand shocks can be sufficient to generate firm growth. Experiments have been particularly illuminating in uncovering patterns in individual decision making, showing how agents respond to the specific changes in circumstances or incentives generated by the experiment. They are most valuable when they complement insight driven by theory.

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