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Bacterial stimulation of copper phytoaccumulation by bioaugmentation with rhizosphere bacteria

ANDREAZZA, Robson; OKEKE, Benedict C.; LAMBAIS, Marcio Rodrigues; BORTOLON, Leandro; MELO, George Wellington Bastos de; CAMARGO, Flavio Anastacio de Oliveira
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
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36.84%
Copper contaminated areas pose environmental health risk to living organisms. Remediation processes are thus required for both crop production and industrial activities. This study employed bioaugmentation with copper resistant bacteria to improve phytoremediation of vineyard soils and copper mining waste contaminated with high copper concentrations. Oatmeal plant (Avena sativa L) was used for copper phytoextraction. Three copper resistant bacterial isolates from oatmeal rhizosphere (Pseudomonas putida A1 Stenotrophomonas maltophilia A2 and Acinetobacter calcoaceticus A6) were used for the stimulation of copper phytoextraction. Two long-term copper contaminated vineyard soils (Mollisol and Inceptisol) and copper mining waste from Southern Brazil were evaluated. Oatmeal plants substantially extracted copper from vineyard soils and copper mining waste. As much as 1549 mg of Cu kg(-1) dry mass was extracted from plants grown in Inceptisol soil. The vineyard Mollisol copper uptake (55 mg Cu kg(-1) of dry mass) in the shoots was significantly improved upon inoculation of oatmeal plants with isolate A2 (128 mg of Cu kg(-1) of shoot dry mass). Overall oatmeal plant biomass displayed higher potential of copper phytoextraction with inoculation of rhizosphere bacteria in vineyard soil to the extent that 404 and 327 g ha(-1) of copper removal were respectively observed in vineyard Mollisol bioaugmented with isolate A2 (S. maltophilia) and isolate A6 (A. calcoaceticus). Results suggest potential application of bacterial stimulation of phytoaccumulation of copper for biological removal of copper from contaminated areas. (C) 2010 Elsevier Ltd. All rights reserved.; CAPES (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior); CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico)...

Copper impacts on grape berry cells : uptake and detoxification

Martins, Viviana; Hanana, Mohsen; Blumwald, Eduardo; Gerós, H.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 ENG
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36.8%
Copper has been extensively used as the active principle of fungicides, since the late 1800s when the “Bordeaux mixture” was developed and its spectacular efficiency proved against fungal pathogens such as downy mildew, which is a large threat to winegrowers. Although initially it seemed to improve plant growth in unproductive lands, repeated use of copper-based fungicides has led to the accumulation of large concentrations of this metal ion in vineyard soils and raised concerns regarding phytotoxicity. As major targets for heavy metal stress, plants have developed a number of mechanisms to withstand the elevated metal levels. Such responses include exclusion, chelation and compartmentation of metal ions. Both the mitochondria and plastids are copper sinks, and the vacuole is believed to constitute a copper delivery pathway within the cell, and not just a sequestration compartment, due to the proximity of the tonoplast to the other organelles of the plant cell. In the present study, grape berry cells (cv. Cabernet Sauvignon) were used as a model system to study the effect of copper on cell growth and viability. In the concentration range of 0 (+ the copper chelator BCS) to 100 μM CuSO4 growth was virtually unaffected. However...

Application of an acoustic wave sensor for copper quantification in the water and particulate matter of the Ria de Aveiro

Yamasaki, A.; Oliveira, J.; Duarte, A. C.; Gomes, M.
Fonte: Global Network for Environmental Science and Technology (Global-NEST) Publicador: Global Network for Environmental Science and Technology (Global-NEST)
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
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Copper is one of the most studied metals and its concentration in estuaries is of great concern, due to its possible toxic effect, as well as to its nutritional importance at low concentrations. A quartz crystal resonator can be used to quantify metals, but it needs to be combined with an electrochemical pre-concentration step to detect low copper concentrations [ 1 ] . Cathodic deposition of the metal at the gold electrodes of a quartz crystal for a period of 3 minutes allowed detecting copper in solutions at concentrations as low as 1.46 μ g L -1 , by measuring the frequency of oscillation of the crystal itself. This methodology was used to determine dissolved copper and “particulate copper” (copper content in the particulate matter) in samples from a channel which connects an estuary (Ria de Aveiro) to the ocean (Atlantic Ocean). The samples were collected at the centre of the channel at the surface and bottom, and at the surface in its Northern bank. Tidal influence was assessed by sampling during summer, at neap and spring tides. Samples were always collected at low tide, flood and high tide. It is known that hydrodynamics and physicochem ical characteristics of the water affect metal transport and its partition between water column...

Copper in plants

Yruela,Inmaculada
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2005 EN
Relevância na Pesquisa
36.81%
Copper is an essential metal for normal plant growth and development, although it is also potentially toxic. Copper participates in numerous physiological processes and is an essential cofactor for many metalloproteins, however, problems arise when excess copper is present in cells. Excess copper inhibits plant growth and impairs important cellular processes (i.e., photosynthetic electron transport). Since copper is both an essential cofactor and a toxic element, involving a complex network of metal trafficking pathways, different strategies have evolved in plants to appropriately regulate its homeostasis as a function of the environmental copper level. Such strategies must prevent accumulation of the metal in the freely reactive form (metal detoxification pathways) and ensure proper delivery of this element to target metalloproteins. The mechanisms involved in the acquisition of this essential micronutrient have not been clearly defined although a number of genes have recently been identified which encode potential copper transporters. This review gives a briefly overview of the current understanding of the more important features concerning copper toxicity and tolerance in plants, and brings information of recent findings on copper trafficking including copper detoxification factors...

Physiological effects of copper in the euryhaline copepod Acartia tonsa: Waterborne versus waterborne plus dietborne exposure.

Pinho, Grasiela Lopes Leães; Pedroso, Mariana Saia; Rodrigues, Sandra Carvalho; Souza, Sandra Silvestre de; Bianchini, Adalto
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.8%
The physiological effects ofwaterborne andwaterborne plus dietborne copper exposure were determined in the euryhaline copepod Acartia tonsa at different salinities (5, 15 and 30 ppt). Copepods were exposed (48 h) to a reported 48-h LC50 for copper (CuCl2), which had been previously determined under the same experimental conditions. Whole body copper accumulation, ion concentrations (Na+, Cl−, Mg2+), and Na+, K+-ATPase activity were the endpoints measured in all experimental groups. Feeding rate was also measured in fed experimental groups. In copper-exposed copepods, whole body copper accumulation was dependent on salinity, decreasing as salinity increased. However, it was similar in copepods exposed to waterborne and waterborne plus dietborne copper, irrespective the salinity tested. Waterborne copper exposure induced a disturbance of the whole body Na+ concentration in all salinities tested. This effect was characterized by an increased whole body Na+ concentration in seawater (salinity 30 ppt) and a decreased whole body Na+ concentration at lower salinities (5 and 15 ppt). The ionoregulatory imbalance in low salinity (5 ppt) was associated with an inhibition of the whole body Na+, K+-ATPase activity, as observed in freshwater fish and crustaceans. When copepods were exposed to waterborne plus dietborne copper...

Acute toxicity, accumulation and tissue distribution of copper in the blue crab Callinectes sapidus acclimated to different salinities: In vivo and in vitro studies

Martins, Camila De Martinez Gaspar; Barcarolli, Indianara Fernanda; Menezes, Eliana Jaime de; Giacomin, Marina Mussoi; Wood, Chris; Bianchini, Adalto
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.81%
In vivo and in vitro studies were performed to evaluate acute toxicity, organ-specific distribution, and tissue accumulation of copper in Callinectes sapidus acclimated to two different experimental salinities (2 and 30 ppt). Blue crabs were quite tolerant to copper. Acute dissolved copper toxicity (96-h LC50 and its corresponding 95% confident interval) was higher at salinity 2 ppt (5.3 (3.50–8.05)_M Cu) than at 30 ppt (53.0 (27.39–102.52)_M Cu). The difference between salinities can be completely explained based on the water chemistry because it disappeared when 96-h LC50 values were expressed as the free Cu2+ ion (3.1 (1.93–4.95)_M free Cu at 2 ppt versus 5.6 (2.33–13.37)_M free Cu at 30 ppt) or the Cu2+ activity (1.4 (0.88–2.26)_M Cu activity at 2 ppt versus 1.7 (0.71–4.07)_M Cu activity at 30 ppt). The relationships between gill Cu burden and % mortality were very similar at 2 and 30 ppt, in accord with the Biotic Ligand Model. In vivo experiments showed that copper concentration in the hemolymph is not dependent on metal concentration in the surrounding medium at either experimental salinity. They also showed that copper flux into the gills is higher than into other tissues analyzed, and that anterior and posterior gills are similarly important sites of copper accumulation at both experimental salinities. In vitro experiments with isolated-perfused gills showed that there is a positive relationship between copper accumulation in this tissue and the metal concentration in the incubation media for both anterior and posterior gills. A similar result was observed at both low and high salinities. Furthermore...

Role of ORF pCT0018 for copper homeostasis in Listeria monocytogenes strain DRDC8.

Hii, Mei Mei
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2009
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36.89%
Sequence analysis of part of a large plasmid carried by Australian environmental isolate of Listeria monocytogenes strain DRDC8 has lead to identification of an islet of genes that encode proteins similar to copper binding and transport genes found in other Gram positive bacteria. Comparative sequence analysis showed that there are at least four genes (pCT0017, pCT0018, pCT0019 and ctpA) on this islet predicted to be involved in copper homeostasis. One of these, ctpA, is predicted to encode a P-type ATPase with a function analogous to CopA, a copper transporting gene in Enterococcus hirae. ORF pCT0017 is likely to be a CopY-like regulatory protein which could control the expression of ctpA. ORF pCT0019 is predicted to be a Cu²⁺ binding protein. In addition, two genes located downstream of the ctpA are predicted to encode a two component regulatory system region. The predicted function of ORF pCT0018 is not clear. A related chromosomal gene (cutR) is predicted to also encode a copper transporting P-type ATPase. To investigate the role of the protein encoded by pCT0018, the growth behavior of L. monocytogenes strain DRDC8, other strains carrying mutations within pCT0018, pCT0019, cutR and ctpA, as well as strains cured of the large plasmid...

Copper tolerance of Listeria monocytogenes strain DRDC8.

Bell, Francesca Y.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2010
Relevância na Pesquisa
36.86%
Listeria monocytogenes is one of the most important food-borne pathogens due to the severity of the disease it can cause. While the virulence factors required for effective colonisation and infection of mammalian hosts have been well described, other genes may modulate disease persistence. For L. monocytogenes strain DRDC8, the ctpA gene encodes a copper transporting P-type ATPase that apparently maintains intra-cellular copper ion homeostasis (Francis & Thomas, 1997a) and is also required for persistent infection of the liver and spleens of mice (Francis & Thomas, 1997b). However, the distribution of this gene is apparently limited to non-clinically derived environmental L. monocytogenes isolates (Bell, 2002). This may be explained by carriage of ctpA on plasmid DNA (Bell, 2002). Based on predictions of function and proximity to the ctpA gene (pCT0020), ORFs pCT0017, pCT0018, pCT0019 and ctpA were identified as a putative a cop-like operon involved in copper ion transport in L. monocytogenes (Bell, 2002). Southern hybridisation analysis was used to confirm that the ctpA gene is carried on plasmid pCT100 in strain DRDC8. In addition, evidence to suggest that ctpA was encoded by bacteriophage DNA was not obtained. Furthermore, sequence analysis of DNA flanking ctpA identified ORFs that encode polypeptide sequences similar to proteins involved in plasmid replication and other plasmid-associated functions. Mating experiments provided evidence to show that plasmid pCT100 is not conjugative. This suggested that lateral transfer of this plasmid between cohabitating organisms may be limited. Sequence analysis of a 37.279 kbp region of plasmid pCT100 from L. monocytogenes strain DRDC8 (GenBank Accession U15554) showed this plasmid had regions of gene content and organisation similar to that of other characterised Listeria plasmids...

Copper toxicosis with hemolysis and hemoglobinuric nephrosis in three adult Boer goats

Bozynski, C.; Evans, T.; Kim, D.; Johnson, G.; Hughes-Hanks, J.; Mitchell, W.; Rottinghaus, G.; Perry, J.; Middleton, J.
Fonte: Amer Assoc Veterinary Laboratory Diagnosticians Inc Publicador: Amer Assoc Veterinary Laboratory Diagnosticians Inc
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
36.84%
Acute and, particularly, chronic copper exposures, along with defects in hepatic copper metabolism, altered excretion of copper, and/or nutritional imbalances between copper and other trace elements, can lead to hepatic accumulation of copper and primary copper toxicosis. There is interspecies variation in susceptibility to copper toxicosis, with sheep being the species most likely to develop this condition. Adult dairy goats and Boer crosses are generally considered resistant to chronic copper toxicosis, especially the hemolytic stage of this disease. The current report is rather unusual in that it describes instances of naturally occurring copper toxicosis with hemolysis and hemoglobinuric nephrosis in 3 adult Boer goats. In 2 of these goats, a possible source of excessive dietary copper was investigated but not definitively identified. In the third goat, the etiologic factors associated with the copper toxicosis were not determined. It appears that mature Boer goats are susceptible to the hemolytic stage of chronic copper toxicosis, which was not observed in a recent, large-scale copper intoxication involving lactating dairy goats. Copper analyses on both liver and kidney samples were necessary to confirm the diagnosis of copper toxicosis in all 3 goats. All feedstuffs associated with instances of copper toxicosis should be analyzed for iron...

CHARACTERIZATION OF THE COPPER RESISTANCE MECHANISM IN STREPTOCOCCUS PNEUMONIAE

Fu, Yue
Fonte: [Bloomington, Ind.] : Indiana University Publicador: [Bloomington, Ind.] : Indiana University
Tipo: Doctoral Dissertation
EN
Relevância na Pesquisa
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Thesis (Ph.D.) - Indiana University, Biochemistry, 2015; Pneumococcal related disease is an infection caused by Streptococcus pneumoniae (pneumococcus), including but not limited to otitis media, pneumoniae and meningitis. About 40 % of the infections are caused by drug resistant Streptococcus pneumoniae (DRSP). The prevalence of DRSP requires identifying novel targets for fighting against pneumococcal related diseases. The bacterial copper homeostasis machinery emerges as one important determinant for survival and virulence for bacteria in human host and serves as one potential drug development target. One cop operon (copY-cupA-copA) has been demonstrated to be essential for copper resistance in S .pneumoniae cells. The transcription of the cop operon is induced in S. pneumoniae isolated from the lungs and nasopharynx of intranasally infected mice and is required for bacterial growth in nasopharynx. The cop operon encodes three proteins, the copper-specific transcriptional regulator CopY, a protein of unknown function prior to this thesis work CupA and a copper-exporting P1B type ATPase CopA. In my thesis work, CupA has been shown to represent a novel class of copper chaperone widely distributed among lactobacillus and streptococcus...

What is the Potential for More Copper Fabrication in Zambia?

World Bank
Fonte: World Bank Publicador: World Bank
Tipo: Economic & Sector Work :: Other Financial Sector Study
ENGLISH
Relevância na Pesquisa
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The copper fabrication industry lies between: (1) the industry that produces copper (as a commodity metal from mined ores as well as from recycling), and (2) the users of copper in finished products such as electronic goods. Copper fabrication involves the manufacture of products such as copper wire, wire rod, low-voltage cable, and other copper based semi-manufactures. Copper is clearly a major input into the copper fabrication industry. However, aside from this supply relationship, the copper mining and refining and copper fabrication industries are almost completely separate, with different drivers, competitive forces, structures, and economics. The former produces a fungible commodity which can be sold anywhere and (in most cases) has a market of last resort in the metal exchanges, while the latter is highly dependent on customer demands and needs, stockholding patterns, and technical requirements. The Government and population of Zambia have long looked to copper fabrication as a potential opportunity for adding more value to the country's copper. Zambia has long held a desire to add more value to its copper...

Evaluation of copper resistant bacteria from vineyard soils and mining waste for copper biosorption

Andreazza,R; Pieniz,S; Okeke,B.C; Camargo,F.A.O
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2011 EN
Relevância na Pesquisa
36.82%
Vineyard soils are frequently polluted with high concentrations of copper due application of copper sulfate in order to control fungal diseases. Bioremediation is an efficient process for the treatment of contaminated sites. Efficient copper sorption bacteria can be used for bioremoval of copper from contaminated sites. In this study, a total of 106 copper resistant bacteria were examined for resistance to copper toxicity and biosorption of copper. Eighty isolates (45 from vineyard Mollisol, 35 from Inceptisol) were obtained from EMBRAPA (Empresa Brasileira de Pesquisa Agropecuária) experimental station, Bento Gonçalves, RS, Brazil (29º09'53.92''S and 51º31'39.40''W) and 26 were obtained from copper mining waste from Caçapava do Sul, RS, Brazil (30º29'43.48''S and 53'32'37.87W). Based on resistance to copper toxicity and biosorption, 15 isolates were identified by 16S rRNA gene sequencing. Maximal copper resistance and biosorption at high copper concentration were observed with isolate N2 which removed 80 mg L-1 in 24 h. Contrarily isolate N11 (Bacillus pumilus) displayed the highest specific copper biosorption (121.82 mg/L/OD unit in 24 h). GenBank MEGABLAST analysis revealed that isolate N2 is 99% similar to Staphylococcus pasteuri. Results indicate that several of our isolates have potential use for bioremediation treatment of vineyards soils and mining waste contaminated with high copper concentration.

New Copper Resistance Determinants in the Extremophile Acidithiobacillus ferrooxidans: A Quantitative Proteomic Analysis

Von Bernath Preece, Diego; Paradela, Alberto; Jerez Guevara, Carlos Antonio; Albar, Juan Pablo; Navarro, Claudio A.; Almárcegui, Rodrigo J.
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo de revista
EN
Relevância na Pesquisa
36.81%
Artículo de publicación ISI; Acidithiobacillus ferrooxidans is an extremophilic bacterium used in biomining processes to recover metals. The presence in A. ferrooxidans ATCC 23270 of canonical copper resistance determinants does not entirely explain the extremely high copper concentrations this microorganism is able to stand, suggesting the existence of other efficient copper resistance mechanisms. New possible copper resistance determinants were searched by using 2DPAGE, real time PCR (qRT-PCR) and quantitative proteomics with isotopecoded protein labeling (ICPL). A total of 594 proteins were identified of which 120 had altered levels in cells grown in the presence of copper. Of this group of proteins, 76 were up-regulated and 44 down-regulated. The up-regulation of RND-type Cus systems and different RND-type efflux pumps was observed in response to copper, suggesting that these proteins may be involved in copper resistance. An overexpression of most of the genes involved in histidine synthesis and several of those annotated as encoding for cysteine production was observed in the presence of copper, suggesting a possible direct role for these metal-binding amino acids in detoxification. Furthermore, the up-regulation of putative periplasmic disulfide isomerases was also seen in the presence of copper...

Copper in plants: acquisition, transport and interactions

Yruela Guerrero, Inmaculada
Fonte: CSIRO Publishing Publicador: CSIRO Publishing
Tipo: Artículo Formato: 344475 bytes; application/pdf
ENG
Relevância na Pesquisa
36.8%
The definitive version is available at: www.publish.csiro.au/journals/fpb; Copper is an essential metal for plants. It plays key roles in photosynthetic and respiratory electron transport chains, in ethylene sensing, cell wall metabolism, oxidative stress protection and biogenesis of molybdenum cofactor. Thus, deficiency in the copper supply can alter essential functions in plant metabolism. On the other hand, copper during decades has been used in agriculture as an antifungal agent and it is also extensively released into the environment by human activities that often cause environmental pollution. Accordingly, excess copper is present in certain regions and environments, and exposure to that can be potentially toxic to plants causing phytotoxicity by the formation of reactive oxygen radicals that damage cells or by the interaction with proteins impairing key cellular processes, inactivating enzymes and disturbing protein structure. Plants have a complex network of metal trafficking pathways in order to appropriately regulate copper homeostasis in response to environmental copper level variations. Such strategies must prevent accumulation of the metal in the freely reactive form (metal detoxification pathways) and to ensure proper delivery of this element to target metalloproteins. The mechanisms involved in the acquisition and the distribution of copper have not been clearly defined although emerging data in last decade...

Copper in plants

Yruela Guerrero, Inmaculada
Fonte: Sociedade Brasileira de Fisiologia Vegetal Publicador: Sociedade Brasileira de Fisiologia Vegetal
Tipo: Artículo Formato: 361730 bytes; application/pdf
ENG
Relevância na Pesquisa
36.81%
http://www.scielo.br/; Copper is an essential metal for normal plant growth and development, although is also potentially toxic. Copper participates in numerous physiological processes and is essential cofactor for many metalloproteins, however, problems arise when excess copper is present in cells. Excess copper inhibits plant growth and impairs important cellular processes (i.e., photosynthetic electron transport). Since copper is both an essential cofactor and a toxic element, different strategies with a complex network of metal trafficking pathways have been evolved in plants to appropriately regulate its homeostasis as a function of changing environmental copper level. Such strategies must prevent accumulation of the metal in the freely reactive form (metal detoxification pathways) and to ensure proper delivery of this element to target metalloproteins. The mechanisms involved in the acquisition of this essential micronutrient have not been clearly defined although a number of genes have been recently identified which encode potential copper transporters. This review gives a briefly overview of the current understanding of main features concerning copper toxicity and tolerance in plants as well as information of recent findings on copper trafficking including copper detoxification factors...

Copper at the Interface of Chemistry and Biology: New Insights into hCtr1 Function and the Role of Histidine in Human Cellular Copper Acquisition

Haas, Kathryn Louise
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 5201855 bytes; application/pdf
Publicado em //2010 EN_US
Relevância na Pesquisa
36.82%

Mechanisms of copper homeostasis are of great interest partly due to their connection to debilitating genetic and neurological disorders. The family of high-affinity copper transporters (Ctr) is responsible for extracellular copper acquisition and internalization in yeast, plants, and mammals, including human. The extracellular domain of the human high-affinity copper transporter (hCtr1) contains essential Cu-binding methionine-rich MXXM and MXM (Mets) motifs that are important for copper acquisition and transport. The hCtr1 extracellular domain also contains potential copper binding histidine (His) clusters, including a high-affinity Cu(II) ATCUN site. As of yet, extracellular His clusters have no established significance for hCtr1 function. We have made model peptides based on the extracellular copper acquisition domain of hCtr1 that is rich in His residues and Mets motifs. The peptides' Cu(I) and Cu(II) binding properties have been characterized by UV-Vis and mass spectrometry. Our findings have been extended to a mouse cell model and we show that His residues are important for hCtr1 function likely because of their contribution to strong copper-binding sites in the hCtr1 extracellular domain responsible for copper acquisition.

Copper's pro-oxidant property is also medicinally promising if it can be harnessed to induce oxidative stress as a cancer chemotherapy strategy. Our lab has designed a photocleavable caged copper complex that can selectively release redox-active copper in response to light. The thermodynamic copper binding properties of these potential chemotherapeutics have been characterized

; Dissertation

Characterization of Drosophila Ctr1a: New Roles for Ctr1 Proteins and Copper in Physiology and Cell Signaling Pathways

Turski, Michelle Lynn
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 18627255 bytes; application/pdf
Publicado em 21/10/2008 EN_US
Relevância na Pesquisa
36.82%

Copper is an essential trace element required by all aerobic organisms as a co-factor for enzymes involved in normal growth, development and physiology. Ctr1 proteins are members of a highly conserved family of copper importers responsible for copper uptake across the plasma membrane. Mice lacking Ctr1 die during embryogenesis from widespread developmental defects, demonstrating the need for adequate copper acquisition in the development of metazoan organisms via as yet uncharacterized mechanisms. The early lethality of the Ctr1 knockout mouse has made it difficult to study the functions of copper and Ctr1 proteins in metazoan development and physiology. Drosophila melanogaster, a genetically tractable system expresses three Ctr1 genes, Ctr1A, Ctr1B and Ctr1C, and may help to further understand the roles of copper and Ctr1 proteins in metazoan development and physiology. Described here is the characterization of Drosophila Ctr1A.

Localization studies using an affinity purified anti-Ctr1A peptide antibody show Ctr1A is predominantly expressed at the plasma membrane in whole embryos and in larval tissues. Ctr1A is an essential gene in Drosophila as loss-of-function mutants, generated by imprecise p-element excision arrest at early larval stages of development. Inductively coupled plasma mass spectroscopy (ICP-MS) demonstrated that whole body copper levels are reduced in Ctr1A mutants and consequently...

Mechanisms of Eukaryotic Copper Homeostasis

Wood, Lawrence Kent
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2010
Relevância na Pesquisa
36.81%

Copper (Cu) is a co-factor that is essential for oxidative phosphorylation, protection from oxidative stress, angiogenesis, signaling, iron acquisition, peptide hormone maturation, and a number of other cellular processes. However, excess copper can lead to membrane damage, protein oxidation, and DNA cleavage. To balance the need for copper with the necessity to prevent accumulation to toxic levels, cells have evolved sophisticated mechanisms to regulate copper acquisition, distribution, and storage. The basic components of these regulatory systems are remarkably conserved in most eukaryotes, and this has allowed the use of a variety of model organisms to further our understanding of how Cu is taken into the cell and utilized.

While the components involved in Cu uptake, distribution, and storage are similar in many eukaryotes, evolution has led to differences in how these processes are regulated. For instance, fungi regulate the components involved in Cu uptake and detoxification primarily at the level of transcription while mammals employ a host of post-translational homeostatic mechanisms. In Saccharomyces cerevisiae, transcriptional responses to copper deficiency are mediated by the copper-responsive transcription factor Mac1. Although Mac1 activates the transcription of genes involved in high affinity copper uptake during periods of deficiency...

Copper Physical Development of Copper Latent Images

Tashker, Gregg; Schreiber, Peter
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
36.8%
Copper physical development of copper latent images was researched. The proposed method for producing copper latent images was to soak a titanium dioxide in a copper (II) sulfate nucleating bath and expose to UV radiation below 4l0nm. The exposures were to produce the copper latent image. Three physical developers were used to try to intensify the latent images. The developers utilize an iron (II)/iron (III) redox system to reduce copper (II) sulfate to copper metal. The developers also contain carboxylic acids as complexing agents for iron (III) ions and cationic surfactants for stability. The printout achieved was not stable and shown not to be copper metal. A copper colloid emulsion was prepared. The three physical developers bleached the copper colloid. A physical developer using formaldehyde as a reducing agent was prepared. The developer produced a brown to purple color change on the copper colloid emulsions.

Copper accumulation, distribution and fractionation in vineyard soils of Victoria, Australia

Pietrzak, Ursula; McPhail, Derry
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
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The use of copper-based fungicides by Victorian vinegrowers has increased the total copper concentration in some vineyard soils to 250 mg/kg compared to background levels of approximately 10 mg/kg. The Australian and New Zealand guidelines for the assessment of contaminated sites recommend that total copper concentrations in soil exceeding 60 mg/kg require environmental investigation, and this level is exceeded in 8 of the 14 vineyards investigated. The focus of this paper is to measure the accumulation, distribution and fractionation of copper in contaminated and uncontaminated soils as a step towards understanding copper existence in soils and its potential for availability to flora and fauna. Physical and chemical properties and total copper concentrations were measured in soil samples from four selected wine-producing regions of Victoria, including vineyard soils and adjacent background soils. Copper fractionation in soils with high total copper concentrations was measured using a selective extraction procedure. Copper in surface soils (0-1 cm) and throughout soil profiles (maximum depth of 50 cm) was separated in the following fractions: water soluble (WS), exchangeable (E), sorbed (S), easily reducible Mn (ERMn), bound to carbonates (CA)...