Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Whole-cell-based sensing systems that respond to cadmium and lead ions have been designed and developed using genetically engineered bacteria. These systems take advantage of the ability of certain bacteria to survive in environments polluted with cadmium and lead ions. The bacteria used in this investigation have been genetically engineered to produce reporter proteins in response to the toxic ions. This was achieved by modifying a strain of Escherichia colito harbor plasmids pYSC1 and pYS2/pYSG1. In these dual-plasmid-based sensing systems, the expression of the reporters beta-galactosidase and red-shifted green fluorescent protein (rs-GFP) was controlled by CadC, the regulatory protein of the cad operon. Regulation of the expression of the reporter proteins is related to the amount of cadmium and lead ions employed to induce the bacteria. The bacterial sensing systems were found to respond to cadmium, lead, and zinc ions, and had no significant response to nickel, copper, manganese, and cobalt.
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PMID:Luminescence-based whole-cell-sensing systems for cadmium and lead using genetically engineered bacteria. 1273 13

The ability of selected phthalocyanines and metallophthalocyanines to block HIV infection has been evaluated in an epithelial HeLa-CD4 cell line with an integrated LTR-beta-galactosidase gene. Sulfonated phthalocyanine itself (PcS), as well as its copper, nickel, and vanadyl chelates, were the most effective in blocking viral infection. These compounds were also very effective in blocking the fusion activity of the viral Env proteins. All of these compounds are expected to bind axial ligands weakly or not at all. In contrast, sulfonated phthalocyanines bearing metals expected to bind axial ligands more tightly (aluminum, cobalt, chromium, iron, silicon, and zinc) were less effective in blocking HIV infection and also less effective at inhibiting fusion. A number of active compounds were found to block binding of gp120 to CD4. Selected cationic and carboxy phthalocyanines, as well as porphyrazines, were also evaluated. Our results indicate that at least some of the compounds render the virus noninfectious, i.e. that they are virucidal. These compounds have potential as microbicides that might be used to provide protection against sexually transmitted HIV.
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PMID:Prevention of HIV-1 infection by phthalocyanines. 1289 93

Immobilized copper(II) affinity chromatography [Cu(II)-immobilized metal affinity chromatography (IMAC)] has been used in proteomics to simplify sample mixtures by selecting histidine-containing peptides from proteolytic digests. This paper examines the specificity of four different support materials with an iminodiacetic acid (IDA) stationary phase in the selection of only histidine-containing peptides in the single step capture-release mode. Three of the sorbents examined were commercially available: HiTrap Chelating HP (agarose), TSK Chelate-5PW, and Poros 20MC. IDA was also immobilized on CIM discs (monolithic glycidylmethacrylate-ethylene dimethacrylate). Tryptic digests of transferrin and beta-galactosidase were used as model samples to evaluate these sorbents. It was found that among the examined matrices, the TSK Chelate-5PW sorbent bound histidine-containing peptides the strongest, while Poros matrix was found to have a high degree of non-specific bindings. Agarose-based columns showed relatively high selectivity and specificity.
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PMID:Contributions of commercial sorbents to the selectivity in immobilized metal affinity chromatography with Cu(II). 1505 70

In vitro test systems using yeast cells are a useful tool for the determination of the estrogenic activity of estrogens, phyto- and xeno-estrogens and can be used for monitoring large sample numbers in a routine analysis procedure. Our conventional transactivation assay functions with an expression plasmid expressing estrogen receptor alpha (ERalpha) under the control of a copper-inducible CUP1 promoter and a reporter plasmid expressing beta-galactosidase under the control of the vitellogenin estrogen response element (ERE). In the novel yeast screen system the lacZ gene in the reporter plasmid was substituted by a gene for green fluorescent protein (GFP). Incubation of yeast with various concentrations of estrogenically active substances led to expression of the reporter gene product GFP in a dose dependent manner. The yeast transactivation assay was further down-scaled to be performed in a microplate scale, which is an important step to facilitate handling of large sample numbers. The sensitivity and reproducibility of the novel test system could be confirmed by analysis of the potencies of various estrogenically active substances. Thus, the newly developed yeast estrogen screen using GFP as a reporter can substitute the assay that has been used for a period of several years.
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PMID:GFP-reporter for a high throughput assay to monitor estrogenic compounds. 1599 33

Freeze-induced perturbations of the protein native fold are poorly understood owing to the difficulty of monitoring their structure in ice. Here, we report that binding of the fluorescence probe 1-anilino-8-naphthalene sulfonate (ANS) to proteins in ice can provide a general monitor of ice-induced alterations of their tertiary structure. Experiments conducted with copper-free azurin from Pseudomonas aeruginosa and mutants I7S, F110S, and C3A/C26A correlate the magnitude of the ice-induced perturbation, as inferred from the extent of ANS binding, to the plasticity of the globular fold, increasing with less stable globular folds as well as when the flexibility of the macromolecule is enhanced. The distortion of the native structure inferred from ANS binding was found to draw a parallel with the extent of irreversible denaturation by freeze-thawing, suggesting that these altered conformations play a direct role on freeze damage. ANS binding experiments, extended to a set of proteins including serum albumin, alpha-amylase, beta-galactosidase, alcohol dehydrogenase from horse liver, alcohol dehydrogenase from yeast, lactic dehydrogenase, and aldolase, confirmed that a stressed condition of the native fold in the frozen state appears to be general to most proteins and pointed out that oligomers tend to be more labile than monomers presumably because the globular fold can be further destabilized by subunit dissociation. The results of this study suggest that the ANS binding method may find practical utility in testing the effectiveness of various additives employed in protein formulations as well as to devise safer freeze-drying protocols of pharmaceutical proteins.
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PMID:ANS fluorescence detects widespread perturbations of protein tertiary structure in ice. 1646 96

Several cell wall-bound glycosidases present in Avena sativa coleoptiles were assayed by following the hydrolysis of p-nitrophenyl-glycosides. Particular emphasis was placed on characterizing some parameters affecting the activity of beta-galactosidase. The pH optimum of this enzyme is 4.5 to 5.5; it is sensitive to copper ions and p-chloromercuribenzoate treatment and apparently has an exceptionally low turnover rate. Indoleacetic acid treatment enhanced in vivo beta-galactosidase activity of coleoptile segments by 36% over control after 60 minutes. This enhancement was prevented by abscisic acid and cycloheximide. High buffer strengths and low pH reduced the indoleacetic acid-enhanced increase in enzyme activity. These data lend support to the following proposed model of indoleacetic acid action. Indoleacetic acid enhances the release of hydrogen ions into the cell wall which promote the activities of cell wall glycosidases, some of which may participate in the cell extension process.
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PMID:Activation of Avena coleoptile cell wall glycosidases by hydrogen ions and auxin. 1665 80

The aim of the present work is the assessment of metal toxicity in runoff, in their contaminated soils and in the groundwater sampled from two mining areas in the region of Marrakech using a microbial bioassay MetPLATE. This bioassay is based on the specific inhibition of the beta-galactosidase enzyme of a mutant strain of Escherichia coli, by the metallic pollutants. The stream waters from all sampling stations in the two mines were all very toxic and displayed percent enzyme inhibition exceeding 87% except SWA4 and SWB1 stations in mine C. Their high concentrations of copper (Cu) and zinc (Zn) confirm the acute toxicity shown by MetPLATE. The pH of stream waters from mine B and C varied between 2.1 and 6.2 and was probably responsible for metal mobilization, suggesting a problem of acid mine drainage in these mining areas. The bioassay MetPLATE was also applied to mine tailings and to soils contaminated by the acidic waters. The results show that the high toxicity of these soils and tailings was mainly due to the relatively concentration of soluble Zn and Cu. The use of MetPLATE in groundwater toxicity testing shows that, most of the samples exhibited low metal toxicity (2.7-45.5% inhibition) except GW3 of the mine B (95.3% inhibition during the wet season and 82.9% inhibition during the dry season). This high toxicity is attributed to the higher than usual concentrations of Cu (189 microg Cu l(-1)) and Zn (1505 microg Zn l(-1)). These results show the potential risk of the contamination of different ecosystems situated to the vicinity of these two metalliferous sites. The general trend observed was an increase in metal toxicity measured by the MetPLATE with increasing total and mobile metal concentrations in the studied matrices. Therefore, the MetPLATE bioassay is a reliable and fast bioassay to estimate the metals toxicity in the aquatic and solids samples.
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PMID:Heavy metal contamination from mining sites in South Morocco: monitoring metal content and toxicity of soil runoff and groundwater. 1737 71

Pseudomonas butanovora possesses an alcohol-inducible alkane monooxygenase, butane monooxygenase (BMO), that initiates growth on C(2)-C(9) alkanes. A lacZ transcriptional reporter strain, P. butanovora bmoX::lacZ, in which the BMO promoter controls the expression of beta-galactosidase activity, was used to show that 1-butanol induced the BMO promoter in the presence or absence of O(2) when lactate-grown, BMO-repressed cells were washed free of lactate and incubated in NH(4)Cl-KNa phosphate buffer. In contrast, when lactate-grown cells of the reporter strain were incubated in phosphate buffer containing the mineral salts of standard growth medium, 1-butanol-dependent induction was significantly repressed at low O(2) (1 to 2% [vol/vol]) and totally repressed under anoxic conditions. The repressive effect of the mineral salts was traced to its copper content. In cells exposed to 1% (vol/vol) O(2), CuSO(4) (0.5 microM) repressed 1-butanol-dependent induction of beta-galactosidase activity. Under oxic conditions (20% O(2) [vol/vol]), significantly higher concentrations of CuSO(4) (2 microM) were required for almost complete repression of induction in lactate-grown cells. A combination of the Cu(2+) reducing agent Na ascorbate (100 microM) and CuSO(4) (0.5 microM) repressed the induction of beta-galactosidase activity under oxic conditions to the same extent that 0.5 microM CuSO(4) alone repressed it under anoxic conditions. Under oxic conditions, 2 microM CuSO(4) repressed induction of the BMO promoter less effectively in butyrate-grown cells of the bmoX::lacZ strain and of an R8-bmoX::lacZ mutant reporter strain with a putative BMO regulator, BmoR, inactivated. Under anoxic conditions, CuSO(4) repression remained highly effective, regardless of the growth substrate, in both BmoR-positive and -negative reporter strains.
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PMID:Evidence for involvement of copper ions and redox state in regulation of butane monooxygenase in Pseudomonas butanovora. 1828 3

The electrochemical oxidation of mono- and disaccharides at various copper-modified electrodes is reported: glassy carbon modified at open circuit or by electrochemical deposition of copper, gold modified by electrochemical deposition, and at bulk copper electrodes. A comparative study of these four electrodes was made by linear sweep voltammetry and amperometry. The maximum oxidation peak separation between disaccharides and monosaccharides is about 200mV. After optimization, amperometric determination of monosaccharides was done at +0.30 versus Ag/AgCl in 0.15M NaOH at the copper-modified gold electrode. Using the developed method, the enzymatic activities of invertase and beta-galactosidase were determined through their reaction with sucrose and lactose, respectively. Validation was carried out by a spectrophotometric method based on 3,5-dinitrosalicylic acid, and it was shown that the proposed electrochemical method is more sensitive. The analytical utility of the copper-modified gold electrode was tested for the determination of organic mercury. Addition of phenylmercury standards to the invertase solution caused a decrease in the enzyme activity, and allowed the determination of phenylmercury in pharmaceutical samples. The concentration has been determined in the 10-55ngml(-1) range.
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PMID:Copper-modified gold electrode specific for monosaccharide detection Use in amperometric determination of phenylmercury based on invertase enzyme inhibition. 1896 85

Metal responsive MerR family transcriptional regulators are widespread in bacteria and activate the transcription of genes involved in metal ion detoxification, efflux, or homeostasis, in response to the presence of cognate metal species in the cytoplasm. MerR family regulators recognize and bind to dyad symmetrical DNA sequences in specific promoters that have a spacer region between the -35 and -10 sequences which is longer than the canonical 16-18 bp spacer for other sigma(70)-dependent promoters. In this study we report beta-galactosidase assays of MerR family-regulated gene expression in the multiple metal resistant bacterium Cupriavidus metallidurans. A series of pMU2385 reporter plasmid derivatives containing cloned MerR family-activated promoters were used to determine metal ion-induced responses from different MerR family regulated promoters, as well as regulators cloned with the cognate promoter into pMU2385. Mercuric ion-responsive MerR and lead ion-responsive PbrR activity was confirmed using this assay system as well as MerR family activator activity on heterologous promoters PcopA, PcadA, and Pzcc from Escherichia coli, Pseudomonas aeruginosa and Bordetella pertussis, respectively. In C. metallidurans CH34, transcription from these promoters was activated by MerR family regulators encoded on the chromosome or megaplasmids in response to copper (PcopA), and lead (PcadA and PzccA), showing that MerR family activators in C. metallidurans can act on MerR family promoters from other organisms, which have sequence differences to the predicted C. metallidurans promoters.
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PMID:Transcriptional activation of MerR family promoters in Cupriavidus metallidurans CH34. 1900 73


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