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)

The gene coding for N-acyl-D-mannosamine dehydrogenase (NAM-DH) from Flavobacterium sp. strain 141-8 was cloned and expressed under the control of a lac promoter in Escherichia coli JM109. The DNA sequence of the gene was determined, and an open reading frame encoding a polypeptide composed of 272 amino acid residues (Mr, 27,473) was identified. The E. coli transformants which showed over 200-fold higher NAM-DH activity than did the Flavobacterium strain produced the enzyme as a protein fused with beta-galactosidase. Despite being a fusion, NAM-DH produced by E. coli transformants appeared unchanged in pH optimum, Km, and substrate specificity from Flavobacterium sp. strain 141-8. This newly recombinant enzyme may be applicable to the quantitative determination of sialic acid in serum.
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PMID:Cloning, sequencing, and expression of the N-acyl-D-mannosamine dehydrogenase gene from Flavobacterium sp. strain 141-8 in Escherichia coli. 185 99

The sensitivities of monoclonal antibody-based enzyme immunoassays for 11-deoxycortisol using alkaline phosphatase (AP), horseradish peroxidase (HRP), beta-galactosidase (beta-GAL) and glucose oxidase (GOD) as labels were compared. The anti-11-deoxycortisol antibody used was that produced in ascites by inoculating antibody-secreting hybridoma cells into mice. Enzyme labeling of 11-deoxycortisol was carried out by the N-succinimidyl ester method. The activated ester of 4-(2-carboxyethylthio)-11-deoxycortisol was treated with each enzyme to give a homologous enzyme-labeled antigen. In the competitive immunoassay, the bound and free enzyme-labeled antigens were separated by a double antibody method and the enzymic activity of the immune precipitate was determined by colorimetric and fluorimetric methods. The AP activity was measured in three ways, using p-nitrophenyl phosphate, nicotinamide adenine dinucleotide phosphate (NADP), and 4-methylumbelliferyl phosphate as substrates. o-Nitrophenyl beta-D-galactopyranoside and 4-methylumbelliferyl beta-D-galactopyranoside were used for beta-GAL, and 3,3',5,5'-tetramethylbenzidine (TMB) and 3-(p-hydroxyphenyl)propionic acid (HPPA) for HRP. In the case of GOD, TMB and HPPA were used in combination with HRP. A dose-response curve with a high sensitivity was obtained in each 11-deoxycortisol assay system by the use of a minimum amount of the enzyme-labeled antigen at an appropriate dilution of monoclonal anti-11-deoxycortisol antibody (Ka = 2 x 10(10) M-1). The amounts of 11-deoxycortisol needed to displace 50% of the bound label ranged from 5 to 15 pg in the colorimetric methods, and 4-9 pg in the fluorimetric methods.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sensitivity of steroid enzyme immunoassays. Comparison of four label enzymes in an assay system using a monoclonal anti-steroid antibody. 268 Jan 24

Pulmonary alveolar macrophages exposed to very short chrysotile asbestos fibers present a typical cytotoxic response: extracellular releases of lactate dehydrogenase and beta-galactosidase, and a decrease in cellular ATP content. The objective of this study was to determine if nicotinamide and 3-aminobenzamide, two inhibitors of the ADP-ribosyl transferase, could modify the in vitro toxicity of chrysotile fibers. After 30 min of pre-exposure with each of the two inhibitors, pulmonary alveolar macrophage monolayers were concomitantly exposed for 18 hours to 50 micrograms of fibers. It was observed that, in a dose-effect relationship (5 to 30 mM), nicotinamide was very effective in reducing the extracellular liberation of the marker enzymes. At 30 mM, the enzyme releases in the medium had returned to control values; the restoration of cell viability was confirmed by ATP levels. Up to 5 mM 3-aminobenzamide did not provide any protection against chrysotile cytotoxicity. Nicotinic acid, a structural analogue of nicotinamide, but not an inhibitor of the ADP-ribosyl transferase, also showed no protective effect. Nicotinamide and 3-aminobenzamide increased the intracellular NAD+ pools, respectively by 350% and 250%. However, with or without additives, the chrysotile fibers caused a constant and significant decrease in NAD+ levels (40-55 pmoles). These results suggest that the inhibition of the nuclear ADP-ribosyl transferase is not the major mechanism by which nicotinamide protects pulmonary alveolar macrophages against the toxicity of chrysotile asbestos fibers.
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PMID:The cytotoxicity of chrysotile asbestos fibers to pulmonary alveolar macrophages. I. Effects of inhibitors of ADP-ribosyl transferase. 285 30

The mutagenicity of urine obtained from five cigarette smokers was investigated using two bacterial assays: the Ames test and the SOS Chromotest. Urinary mutagens were extracted on Amberlite XAD-2 resin. Four urine samples showed activity towards Salmonella typhimurium tester strain TA98 with S9 mix while no SOS-inducing activity could be measured with Escherichia coli strain PQ37 in the SOS Chromotest. Using factorial design and a positive control benzo[a]pyrene (BaP), the concentration of S9, nicotinamide adenine dinucleotide phosphate (NADP) and glucose-6-phosphate (G6P) were optimized (2%, 0.5 mM and 10 mM respectively) for the SOS Chromotest. The SOS-inducing power of BaP was 1.42/nM with the standard S9 mix and 3.26/nM with the optimized S9 mix. B buffer and the age of L-broth were found to decrease the sensitivity of beta-galactosidase assays in the SOS Chromotest. A 4000-fold urine concentrate from a smoker was finally tested using the Ames test and the modified SOS Chromotest. Mutagenic and toxic activities were found toward tester strain TA98 (+S9 mix) showing that the SOS Chromotest is not at present suitable for assaying urinary mutagens in the presence of an in vitro metabolic activating mixture.
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PMID:Applicability of the SOS Chromotest to detect urinary mutagenicity caused by smoking. 313 23

The general methodology used for the determination of lactose in milk is considered, namely, polarimetry, gravimetry, infrared, colorimetry, gas-liquid chromatography, and high pressure liquid chromatography. The criteria for selecting an ideal analytical method followed by the relevance of most of these criteria in enzymatic methodology are discussed. The principle of the Boehringer-Mannheim method is presented, i.e., lactose is hydrolyzed to glucose and beta-galactose in the presence of beta-galactosidase and water. beta-Galactose is then oxidized by nicotinamide-adenine dinucleotide to galactonic acid in the presence of beta-galactose dehydrogenase. The amount of reduced nicotinamide-adenine dinucleotide formed is stoichiometric with the amount of lactose and is measured at 340 nm in a spectrophotometer possessing a slit width of less than or equal to 10 nm. The results of a recent Association of Official Analytical Chemists collaborative study of the B-M method are presented. From the overall mean of results on all samples, determinations by the enzymatic method averaged .49% lower than by the Association of Official Analytical Chemists gravimetric method. Standard deviations were similar for three sets of blind duplicates, which ranged between 3.67 and 4.55% lactose. F-Values revealed that variations between means obtained by laboratories differed significantly as compared with variations within laboratory means. The method has received Official First Action recognition by Association of Official Analytical Chemists.
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PMID:Determination of lactose by an enzymatic method. 406 42

The suitability of non-replicating thymidine kinase deficient herpes simplex virus type 1 expressing bacterial beta-galactosidase (tk-lacZ HSV-1) as a transfer vehicle into sympathetic preganglionic neurons in vivo was assessed. Many sympathoadrenal preganglionic neurons (451 +/- 105) with normal morphology were identified using beta-galactosidase histochemistry two days after inoculation of tk-lacZ HSV-1 into the adrenal gland of hamsters. Beta-galactosidase activity co-localized with nicotinamide adenine dinucleotide phosphate-diaphorase-positive sympathetic preganglionic neurons in the nucleus intermediolateralus, pars principalis. The maximal number of beta-galactosidase expressing neurons was found two days post-inoculation but this number dropped dramatically after this time. An inflammatory infiltrate was abundant around infected neurons and in the white matter at five days and infected neurons appeared morphologically abnormal. At 26 days, the infiltrate was still present but no infected sympathoadrenal preganglionic neurons were detected. Approximately 25% fewer nicotinamide adenine dinucleotide phosphate-diaphorase-positive neurons in the nucleus intermediolateralis, pars principalis were counted ipsilaterally than contralaterally in animals infected for 14, 21 or 26 days with tk-lacZ HSV-1, compared to the 3% difference in animals mock-infected for 26 days. Approximately 33% of the estimated number of sympathoadrenal preganglionic neurons infected with tk-lacZ HSV-1 at five days were apoptotic or necrotic. About 60% of neurons infected with tk-lacZ HSV-1 at two days no longer expressed nicotinamide adenine dinucleotide phosphate-diaphorase at 14-26 days. In conclusion, the non-replicating thymidine kinase deficient HSV-1 was efficiently retrogradely transported from the adrenal gland to infect sympathoadrenal preganglionic neurons. These gene transfer experiments using tk-lacZ HSV-1 suggest that foreign gene expression in sympathetic preganglionic neurons in vivo may be maximal two days after inoculation when beta-galactosidase was expressed in the greatest number of sympathetic preganglionic neurons. After two days, fewer neurons expressed beta-galactosidase and the presence of tk-lacZ HSV-1 appeared to be altering protein expression in sympathetic preganglionic neurons and/or leading to the demise of the infected neuron.
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PMID:Gene transfer into sympathetic preganglionic neurons in vivo using a non-replicating thymidine kinase-deficient herpes simplex virus type 1. 927 1

A non-replicating triple-mutant herpes simplex virus (14H delta 3vhsZ) expressing the bacterial marker enzyme beta-galactosidase, was assessed for neurotropism and cytopathic effects as a vector for gene transfer into differentiated phaeochromocytoma 12 cells in vitro and into spinal sympathetic neurons in vivo. In the in vivo study, the 14H delta 3vhsZ was injected into the adrenal gland of hamsters. For comparison, an evaluation of two adenovirus vectors, AdCA17lacZ and AdCA36lacZ, was performed. Infection of the differentiated phaeochromocytoma 12 cells by 14H delta 3vhsZ resulted in intense beta-galactosidase staining in 80-90% of the cells without changes in cell morphology, detected by light microscopy, after a period of four days. No cytoskeletal disruption was detected by immunocytochemistry for the neurofilament protein and no apoptosis was demonstrated by the Hoescht stain for nuclear chromatin in virus-infected cells in comparison to mock-infected control cells. Twoto three days after adrenal inoculation with 14H delta 3vhsZ, beta-galactosidase was detected in 240 preganglionic neurons per hamster (n = 8), a number equal to about 25% of the population of targeted neurons. The beta-galactosidase reaction product extended throughout the normal kite-shaped neuronal somata and extensive dendritic arbour. The number decreased to 120 by five days (n = 3) and to two by eight days (n = 4). This decrease was presumably due to loss of expression of the marker gene and not to cell death because, at eight days, the number of sympathetic pregnanglionic neurons in the nucleus intermediolateralis, pars principalis, that were immunoreactive for the neurotransmitter enzyme choline acetyltransferase, and demonstrated nicotinamide adenine dinucleotide phosphate-diaphorase activity, were the same on the infected left side of the cord as on the uninfected right side. Inflammatory cells surrounded some of the infected neurons at five days but by eight days the infiltrate was reduced. Infection of differentiated phaeochromocytoma 12 cells by AdCA17lacZ and AdCA36lacZ also resulted in marker gene expression in a large proportion of the cells (80-90%) in the absence of cytopathic effects. In contrast, four days after adrenal injection of AdCA17lacZ or AdCA36lacZ (n = 5 for each) only an average of three preganglionic neurons per hamster expressed beta-galactosidase activity, despite clear adrenal infection. AdCA17lacZ and AdCA36lacZ both produced light patches of staining confined to the neuronal soma. These neurons had normal morphology but sometimes were surrounded by an inflammatory infiltrate. In conclusion, the non-replicating herpes simplex virus, 14H delta 3vhsZ, had minimal cytotoxic effects in neurons, in vitro or in vivo, and was efficiently transported from the adrenal gland to infect many sympathoadrenal pregnanglionic neurons. In contrast, very few neurons demonstrated beta-galactosidase activity after injection into the adrenal gland of AdCA17lacZ and AdCA36lacZ. Therefore, 14H delta 3vhsZ is a more suitable vector than either of the adenovirus vectors tested for eliciting short-term changes in preganglionic neuron gene expression.
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PMID:Analysis of a multi-mutant herpes simplex virus type 1 for gene transfer into sympathetic preganglionic neurons and a comparison to adenovirus vectors. 969 36

Recent work suggesting that cellular oxidative stress exerts an inhibitory effect on aromatic hydrocarbon receptor (AHR)-dependent gene expression led us to test the hypothesis that pro-oxidant environmental pollutants might alter the induction of detoxification genes by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an AHR ligand. We found that, in mouse hepatoma Hepa-1 cells, TCDD-inducible cytochrome P450, Cyp1a1, and nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase (Nqo1) mRNA accumulation were differentially affected by cadmium (Cd(2+)), chromium (Cr(6+)), and arsenic (As(3+)). Cadmium or arsenic did not change Cyp1a1 mRNA levels but did enhance TCDD-inducible levels of Nqo1 mRNA, an effect that paralleled the ability of these metals to activate a beta-galactosidase gene reporter system regulated by an electrophile response promoter element. Chromium inhibited mRNA accumulation for both Cyp1a1 and Nqo1. Manipulation of cellular thiol status did not modify the response to combined chromium-TCDD exposure, suggesting that the response was not caused by oxidative stress. Chromium did not block DNA-binding competence of the AHR and did not have an effect on mRNA stability, but it inhibited Cyp1a1 gene transcription and the expression of an AHR-dependent luciferase reporter. These data indicate that coexposure to pro-oxidant metals and AHR ligands, which is common in the environment, can disrupt the regulation of phase I and phase II detoxification genes, leading to imbalances in gene expression that may have important consequences for the toxicity of complex mixtures.
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PMID:Disruption of dioxin-inducible phase I and phase II gene expression patterns by cadmium, chromium, and arsenic. 1097 92

Glucose-6-phosphate dehydrogenase (G6PD) is involved in the generation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) and the maintenance of the cellular redox balance. The biological effects of G6PD deficiency in nucleated cells were studied using G6PD-deficient human foreskin fibroblasts (HFF). In contrast to that of normal HFF, the doubling time of G6PD-deficient cells increased readily from population doubling level (PDL) 15 to 63. This was accompanied by a significant increase in the percentage of G(1) cells. The slow-down in growth preceded an early entry of these cells into a nondividing state reminiscent of cellular senescence. These cells exhibited a significant increase in level of senescence-associated beta-galactosidase (SA-beta-gal) staining. The importance of G6PD activity in cell growth was corroborated by the finding that ectopic expression of active G6PD in the deficient cells prevented their growth retardation and early onset of senescence. Mechanistically, the enhanced fluorescence in dichlorofluorescin (H(2)DCF)-stained G6PD-deficient cells suggests the possible involvement of reactive oxygen species in senescence. Taken together, our results show that G6PD deficiency predisposes human fibroblasts to retarded growth and accelerated cellular senescence. Moreover, G6PD-deficient HFF provides a useful model system for delineating the effects of redox alterations on cellular processes.
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PMID:Enhanced oxidative stress and accelerated cellular senescence in glucose-6-phosphate dehydrogenase (G6PD)-deficient human fibroblasts. 1098 Apr 4

Aging appears to be an irreversible process. Here we report that nicotinamide (NAA) can induce rapid and reversible reversion of aging phenotypes in human diploid fibroblasts in terms of cell morphology and senescence-associated beta-galactosidase activity. Although NAA seems to enhance the replicative potential of the cells, it has little effect on their growth rate and life span, suggesting that NAA action is rather separated from the cellular replicative system. The effects are unique to NAA: none ofthe NAA-related compounds examined (an NAD precursor/niacin, NAD analogs, and poly(ADP-ribose) polymerase inhibitors) exerted similar effects. Thus, NAD-related metabolism and poly(ADP-ribosyl)ation are unlikely related to the NAA action. On the other hand, histone acetyltransferase (HAT) activity was elevated in NAA-exposed cells, while in aged cells, HAT activity and histone H4 acetylation were lowered. Taken together, the results suggest that NAA may cause rejuvenation by restoring, at least in part, altered gene expression in aged cells through its activation of HAT.
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PMID:Rapid reversion of aging phenotypes by nicotinamide through possible modulation of histone acetylation. 1181 60


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