scholarly journals Mercury and cadmium trigger expression of the copper importer Ctr1B, which enables Drosophila to thrive on heavy metal-loaded food

2009 ◽  
Vol 390 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Kuppusamy Balamurugan ◽  
Haiqing Hua ◽  
Oleg Georgiev ◽  
Walter Schaffner
Keyword(s):  
Heavy Metal ◽  
Binding Sites ◽  
Sequence Motifs ◽  
Excess Copper ◽  
Number Of Genes ◽  
Zinc Cadmium ◽  
Copper Zinc ◽  
Dna Sequence Motifs ◽  
Transcription Factor 1 ◽  
Transcription Enhancer

Abstract Organisms from insects to mammals respond to heavy metal load (copper, zinc, cadmium, and mercury) by activating the metal-responsive transcription factor 1 (MTF-1). MTF-1 binds to short DNA sequence motifs, termed metal response elements, and boosts transcription of a number of genes, notably those for metallothioneins. In Drosophila, MTF-1 somewhat counter-intuitively also activates transcription of a copper importer gene (Ctr1B) in response to copper starvation. Here, we report that mutant flies lacking Ctr1B are extremely sensitive to cadmium and mercury treatment, but can be rescued by excess copper in the food. We thus propose that copper, by competing for binding sites on cellular proteins, alleviates the toxic effects of mercury and cadmium. Such a scenario also explains a seemingly fortuitous metal response, namely, that cadmium and mercury strongly induce the expression of a Ctr1B reporter gene. Thus, the transcription enhancer/promoter region of the Ctr1B copper importer gene is subject to three modes of regulation. All of them depend on MTF-1 and all make biological sense, namely, (i) induction by copper starvation, (ii) repression by copper abundance, and (iii), as shown here, induction by cadmium or mercury at normal copper supply.

RECOVERY AND EXTRACTION OF HEAVY METAL IONS USING IONIC LIQUID AS GREEN SOLVENT

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4051-4056 ◽  
Author(s):  
MASAMI KUMANO ◽  
TOMOKI YABUTANI ◽  
JUNKO MOTONAKA ◽  
YUJI MISHIMA
Keyword(s):  
Heavy Metal ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Volume Ratio ◽  
Chelating Agent ◽  
Good Solubility ◽  
Zinc Cadmium ◽  
Copper Zinc

Ionic liquids are expected to replace conventional organic solvents in organic synthesis, solvent extraction and electrochemistry due to their unique characters such as low volatility, high stability and so on. In this work, N , N ,-diethyl- N -methyl- N -(2-methoxyethyl) ammonium bis(trifluoromethansulfonyl)imide was used as an alternative solvent to extract heavy metal ions. As the extracting conditions, the additional effect of 8-hydroxyquinoline (8-HQ) as metal chelating agent into ionic liquids, shaking time and volume ratio were investigated. As extraction efficiency depended on 8-HQ concentration significantly, in order to extract high concentrated metal ions the solubility of 8-HQ into ionic liquid was tested. N , N ,-diethyl- N -methyl- N -(2-methoxyethyl) ammonium bis(trifluoromethansulfonyl)imide had good solubility of 8-HQ. Consequently, 5 μmol of copper, zinc, cadmium and manganese could be completely recovered with 100 μl of ionic liquid.

scholarly journals G-quadruplexes are transcription factor binding hubs in human chromatin

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jochen Spiegel ◽  
Sergio Martínez Cuesta ◽  
Santosh Adhikari ◽  
Robert Hänsel-Hertsch ◽  
David Tannahill ◽  
...  
Keyword(s):  
Binding Sites ◽  
Regulation Of Gene Expression ◽  
Secondary Structures ◽  
Sequence Motifs ◽  
Binding Interaction ◽  
Double Stranded Dna ◽  
Genome Wide ◽  
Highly Expressed Genes ◽  
Dna Secondary Structures ◽  
Dna Sequence Motifs

AbstractBackgroundThe binding of transcription factors (TF) to genomic targets is critical in the regulation of gene expression. Short, double-stranded DNA sequence motifs are routinely implicated in TF recruitment, but many questions remain on how binding site specificity is governed.ResultsHerein, we reveal a previously unappreciated role for DNA secondary structures as key features for TF recruitment. In a systematic, genome-wide study, we discover that endogenous G-quadruplex secondary structures (G4s) are prevalent TF binding sites in human chromatin. Certain TFs bind G4s with affinities comparable to double-stranded DNA targets. We demonstrate that, in a chromatin context, this binding interaction is competed out with a small molecule. Notably, endogenous G4s are prominent binding sites for a large number of TFs, particularly at promoters of highly expressed genes.ConclusionsOur results reveal a novel non-canonical mechanism for TF binding whereby G4s operate as common binding hubs for many different TFs to promote increased transcription.

Polyamine-substituted epoxy-grafted silica for aqueous metal recovery

2011 ◽  
Vol 65 (6) ◽  
Author(s):  
Madjid Hadioui ◽  
Med Mecherri ◽  
Rastislav Šípoš ◽  
Yan Yvon ◽  
Patrick Sharrock
Keyword(s):  
Heavy Metal ◽  
Silica Gel ◽  
Aqueous Media ◽  
Acid Washing ◽  
Zinc Cadmium ◽  
Copper Zinc ◽  
Flow Through ◽  
Terminal Amino ◽  
Silica Gel Particles ◽  
General Method

AbstractGlycidoxypropyltriethoxysilane (GPS) was used as a reactive silane to graft metal- complexing ligands onto silica gel in aqueous media under mild conditions. The synthesis entailed the reaction of GPS with silica gel, followed by grafting polyamine onto the epoxy functional group. GPS was added to silica gel in ethanol with 5 vol. % water and the mixture was air-dried for 24 h. Subsequently, excess amounts of polyamines: triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine were individually added to the silanised silica, followed by solvent evaporation and ovendrying at 60°C. The ligand-grafted silica gel particles showed a rapid heavy metal uptake in batch or flow-through experiments with capacities reaching 0.1 mmol g−1 for copper, zinc, cadmium, or lead ions. Columns packed with the modified particles could be readily regenerated by acid-washing with only a small decrease in activity. The particles could be used for the colourimetric detection of heavy metal pollution or for pre-concentration for analytical purposes. Competition between Cu2+, Zn2+, Pb2+, and Cd2+ ions for the three synthesised silica showed that Cu2+ ions were adsorbed more strongly than the other metal ions. The general method developed can be applied to graft other molecules with terminal amino groups for other purposes.

Metal-responsive transcription factor-1 (MTF-1) selects different types of metal response elements at low vs. high zinc concentration

2004 ◽  
Vol 385 (7) ◽  
Author(s):  
Y. Wang ◽  
I. Lorenzi ◽  
O. Georgiev ◽  
W. Schaffner
Keyword(s):  
Transcription Factor ◽  
Dna Sequence ◽  
Zinc Concentration ◽  
Sequence Motifs ◽  
Response Elements ◽  
High Zinc ◽  
Different Types ◽  
Zinc Concentrations ◽  
Dna Sequence Motifs ◽  
Transcription Factor 1

AbstractMetalresponsive transcription factor-1 (MTF-1) is a zinc finger protein with a central role in heavy metal homeostasis/ detoxification. MTF-1 binds to DNA sequence motifs known as metal response elements (MREs) with a core consensus TGCRCNC. Since MTF-1 is also involved in other stress responses, we tested whether it is able to recognize different types of DNA sequence motifs. To this end we selected MTF-1-binding oligonucleotides from a collection of random sequences. Since MTF-1 binds to known target sequences at relatively high zinc concentrations, oligonucleotide selection was performed in a mammalian cell nuclear extract both at high and low zinc concentrations. Irrespective of zinc concentration, we find a robust representation of MRE consensus sequences, however with specific features. Selection was most efficient at 100 M zinc, yielding many oligonucleotides with two MRE motifs in divergent orientation of the sequence

Metallic pollution in clogging materials of urban porous pavements

1995 ◽  
Vol 32 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Valérie Colandini ◽  
Michel Legret ◽  
Yves Brosseaud ◽  
Jean-Daniel Baladès
Keyword(s):  
Heavy Metal ◽  
Particle Size ◽  
Road Traffic ◽  
Total Concentration ◽  
Extraction Procedure ◽  
Interaction Strength ◽  
Metal Mobility ◽  
Residual Fraction ◽  
Metal Contents ◽  
Copper Zinc

Porous pavements infiltrated with stormwater are faced with clogging problems: runoff particles seep and clog the pervious surface layer of these structures. Clogging material samples (in the form of sludge) have been collected in cleaning operations on the pervious asphalt. This study aims at characterizing these materials, particle size distribution, heavy metal contents by particle size, and studying interactions between metals and particles. A sequential extraction procedure proposed by the experts of the Community Bureau of Reference (B.C.R.) was applied to provide information about heavy metal distribution on particles and to evaluate interaction strength, and consequently potential metal mobility when chemical variations occurred in the environment. Mainly made up of sand, the materials are polluted with lead, copper, zinc and cadmium. The concentrations appeared to be linked with road traffic intensity. The heavy metal contents by particle size showed that the finer are the particles, the higher are the heavy metal concentrations. Heavy metals were found potentially labile; metals contents in the residual fraction (mineral fraction) represented less than 20 % of the total concentration. Cadmium and zinc were apparently more labile than lead and copper.

scholarly journals Genome Wide Analysis of the Transcriptional Profiles in Different Regions of the Developing Rice Grains

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ting-Ying Wu ◽  
Marlen Müller ◽  
Wilhelm Gruissem ◽  
Navreet K. Bhullar
Keyword(s):  
Gene Expression ◽  
Dna Sequence ◽  
Expression Patterns ◽  
Grain Filling ◽  
Aleurone Layer ◽  
Rice Grain ◽  
Sequence Motifs ◽  
Grain Development ◽  
Spatio Temporal ◽  
Dna Sequence Motifs

Abstract Background Rice is an important food source for humans worldwide. Because of its nutritional and agricultural significance, a number of studies addressed various aspects of rice grain development and grain filling. Nevertheless, the molecular processes underlying grain filling and development, and in particular the contributions of different grain tissues to these processes, are not understood. Main Text Using RNA-sequencing, we profiled gene expression activity in grain tissues comprised of cross cells (CC), the nucellar epidermis (NE), ovular vascular trace (OVT), endosperm (EN) and the aleurone layer (AL). These tissues were dissected using laser capture microdissection (LCM) at three distinct grain development stages. The mRNA expression datasets offer comprehensive and new insights into the gene expression patterns in different rice grain tissues and their contributions to grain development. Comparative analysis of the different tissues revealed their similar and/or unique functions, as well as the spatio-temporal regulation of common and tissue-specific genes. The expression patterns of genes encoding hormones and transporters indicate an important role of the OVT tissue in metabolite transport during grain development. Gene co-expression network prediction on OVT-specific genes identified several distinct and common development-specific transcription factors. Further analysis of enriched DNA sequence motifs proximal to OVT-specific genes revealed known and novel DNA sequence motifs relevant to rice grain development. Conclusion Together, the dataset of gene expression in rice grain tissues is a novel and useful resource for further work to dissect the molecular and metabolic processes during rice grain development.

Bioremediation of Acid Mine Drainage in an Uranium Deposit

2007 ◽  
Vol 20-21 ◽  
pp. 248-257 ◽  
Author(s):  
Stoyan N. Groudev ◽  
Plamen S. Georgiev ◽  
Irena Spasova ◽  
Marina Nicolova
Keyword(s):  
Mine Drainage ◽  
Plant Biomass ◽  
Uranium Deposit ◽  
Water Flow Rate ◽  
Ambient Temperatures ◽  
Zinc Cadmium ◽  
Copper Zinc ◽  
Cadmium Lead ◽  
Dead Plant ◽  
The Individual

Acid drainage waters generated in the uranium deposit Curilo, Bulgaria, were treated by means of different passive systems such as natural and constructed wetlands, alkalizing limestone drains, permeable reactive multibarriers and a rock filter, used separately or in different combinations. The waters had a pH in the range of about 2 – 4 and contained radionuclides (uranium, radium), heavy metals (copper, zinc, cadmium, lead, nickel, cobalt, iron, manganese), arsenic and sulphates in concentrations usually much higher than the relevant permissible levels for waters intended for use in agriculture and/or industry. The water flow rate through the individual systems was different and not stable, and varied in the range approximately from 0.02 to 1.5 l/s. Efficient removal of pollutants was achieved by means of these systems during the different climatic seasons, even during the cold winter months at water and ambient temperatures close to 0 oC. The removal was due to different mechanisms but microbial sulphate reduction, biosorption by living and dead plant biomass and chemical neutralization played the main roles.

scholarly journals Distinctiveness of Genotypes of Helicobacter pylori in Calcutta, India

2000 ◽  
Vol 182 (11) ◽  
pp. 3219-3227 ◽  
Author(s):  
Asish K. Mukhopadhyay ◽  
Dangeruta Kersulyte ◽  
Jin-Yong Jeong ◽  
Simanti Datta ◽  
Yoshiyuki Ito ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
East Asia ◽  
Disease Status ◽  
Gene Pools ◽  
Sequence Motifs ◽  
The West ◽  
Global Understanding ◽  
H Pylori ◽  
Dna Sequence Motifs ◽  
Cytotoxin Gene

ABSTRACT The genotypes of 78 strains of Helicobacter pylori from Calcutta, India (55 from ulcer patients and 23 from more-benign infections), were studied, with a focus on putative virulence genes and neutral DNA markers that were likely to be phylogenetically informative. PCR tests indicated that 80 to 90% of Calcutta strains carried the cag pathogenicity island (PAI) and potentially toxigenic vacAs1 alleles of the vacuolating cytotoxin gene (vacA), independent of disease status. This was higher than in the West (where cag PAI+ vacAs1 genotypes are disease associated) but lower than in east Asia. The iceA2 gene was weakly disease associated in Calcutta, whereas in the West the alternative but unrelatediceA1 gene at the same locus is weakly disease associated. DNA sequence motifs of vacAm1 (middle region) alleles formed a cluster that was distinct from those of east Asia and the West, whereas the cagA sequences of Calcutta and Western strains were closely related. An internal deletion found in 20% of Calcutta iceA1 genes was not seen in any of ∼200 strains studied from other geographic regions and thus seemed to be unique to this H. pylori population. Two mobile DNAs that were rare in east Asian strains were also common in Calcutta. About 90% of Calcutta strains were metronidazole resistant. These findings support the idea that H. pylori gene pools differ regionally and emphasize the potential importance of studies of Indian and other non-Western H. pylori populations in developing a global understanding of this gastric pathogen and associated disease.

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