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Sample records for enzyme induction

  1. Enzyme induction in cryopreserved human hepatocyte cultures.

    PubMed

    Kafert-Kasting, Sabine; Alexandrova, Krassimira; Barthold, Marc; Laube, Britta; Friedrich, Gerhard; Arseniev, Lubomir; Hengstler, Jan G

    2006-03-15

    Freshly isolated human hepatocytes are considered as the gold standard for in vitro testing of drug candidates. Meanwhile also cryopreserved human hepatocyte suspensions are available. However, a drawback of these cells is the incalculability of attachment to the culture dish. Therefore, we established a technique freezing hepatocytes cultured on a collagen gel. After thawing damaged cells were removed to a certain extent by gentle washing with culture medium prior to adding an upper gel layer. The morphology of the resulting hepatocyte cultures could not be distinguished from that of non-frozen cells. However, basal activities of cytochrome P450 isoforms decreased in cryopreserved compared to non-frozen hepatocytes, as evidenced by analysis of testosterone hydroxylation (OHT) in positions 6beta, 16alpha, 2beta and 6alpha. Nevertheless, enzyme induction factors caused by 24 h incubation with 50 microM rifampicin were similar in cryopreserved and non-frozen hepatocytes. In cryopreserved hepatocytes rifampicin caused an increase in mean values of 6beta-OHT formation from 57.2 to 157.7 pmol/well/min (2.8-fold), compared to an increase from 115.8 to 269.1 pmol/well/min (2.3-fold) in non-frozen cells. Similarly, 16alpha- and 2beta-OHT showed induction factors of 2.4- and 2.3-fold in cryopreserved compared to 1.6- and 2.4-fold in non-frozen hepatocytes, respectively. In conclusion, human hepatocytes cryopreserved on collagen gels show a clear induction of CYP3A4 by rifampicin, although the basal activities are reduced compared to non-frozen cells. PMID:16473453

  2. [Examination of hormonal contraceptives by enzyme induction (author's transl)].

    PubMed

    Klinger, G; Hempel, E

    1979-01-01

    The influence of drug stimulated biotransformation on the biological effectiveness of two different contraceptives (Deposition and Gravistat) was observed.--Phenobarbital, a potent enzyme inducer, is known to increase the metabolism of steroid hormones, including estrogens and progrestogens. -- The clinical symptoms of drug mediated enzyme induction of hormonal steroid contraceptives are dysfunctional bleedings. This phenomenon is discussed. PMID:463398

  3. The induction of microsomal electron transport enzymes.

    PubMed

    Waterman, M R; Estabrook, R W

    1983-01-01

    Liver endoplasmic reticulum contains as NADPH-dependent electron transport complex where the family of hemeproteins, termed cytochrome P-450, serve as catalysts for the oxidation of a variety of different organic chemicals. The content and inventory of the types of cytochrome P-450 is readily modified following in vivo treatment of animals with 'inducing agents' such as barbiturates, steroids and polycyclic hydrocarbons. Recent studies have applied the methods of molecular biology to evaluate changes in the transcription and translation of genomic information occurring concomitant with the initiation of synthesis of various types of cytochrome P-450. The ability to isolate unique cytochrome P-450 proteins and to prepare specific antibodies now permits the study of in vitro translation of mRNA and the preparation of specific cDNAs. The present review summarizes the historic background leading to current concepts of cytochrome P-450 induction and describes recent advances in our knowledge of the regulation of cytochrome P-450 synthesis in the liver. PMID:6353196

  4. Enzyme induction, mutagen activation and carcinogen testing in yeast

    SciTech Connect

    Wiseman, A.

    1987-01-01

    This book documents the scientific basis for using yeasts to detect mutagenic chemicals likely to cause cancer in humans, a phenomenon explained by the presence of the enzyme cytochrome P-450 in some tissues. Explains the nature and roles of this enzyme in detail, and explores a range of related topics, including the genetic features of yeast, the mitochondrial DNA system and petite mutants, the molecular biology of transcription of genes in yeast, and enzyme induction. Also examined is DNA repair and how mutagenesis in yeast and other microorganisms relates to the practical detection of mutagens.

  5. Induction of drug metabolizing enzymes by sulfinpyrazone.

    PubMed

    Walter, E; Staiger, C; de Vries, J; Zimmermann, R; Weber, E

    1981-01-01

    A previous interaction study of sulfinpyrazone (Anturano) suggested that it induced microsomal drug metabolizing enzymes in the liver. To verify this finding the effect of sulfinpyrazone 800 mg per day for four weeks was investigated in ten healthy volunteers. Both the therapeutic actions of sulfinpyrazone, the uricosuric and the antiaggregating effects, were demonstrated (p less than 0.05). The influence on the microsomal drug metabolizing system in the liver was demonstrated by an increase in serum-gamma-glutamyl transpeptidase from 15.1 to 23.3 U/l (p greater than 0.05), a significant increase in the urinary excretion of d-glucaric acid (29.6 to 77.9 microMol/24 h, p less than 0.05) and an increase in antipyrine clearance from 50.3 ml/min to 83.9 ml/min (p less than 0.05). The possibility of enhancement of drug metabolism during treatment with sulfinpyrazone in combination with other drugs should be kept in mind. PMID:6113147

  6. In vitro induction of lysosomal enzymes by phagocytosis.

    PubMed

    Axline, S G; Cohn, Z A

    1970-06-01

    The in vitro induction of lysosomal enzymes by phagocytosis was demonstrated in cultivated mouse peritoneal macrophages. The contribution of each of several steps in the endocytic process to enzyme induction was examined. The enzymatic response after the uptake of equal numbers of erythrocytes (RBC) and nondigestible particles were compared. Phagocytosis of RBC produced a marked increase in the levels of acid phosphatase, beta-glucuronidase, and cathepsin D. Puromycin (1 microg/ml) inhibited the enzyme response. In contrast, phagocytosis of polyvinyl toluene, polystyrene, and insoluble starch particles produced no increase in macrophage lysosomal enzymes, although fusion of phagosomes with preexisting lysosomes occurred normally. The endocytic stimulus to synthesis of inducible lysosomal enzymes, therefore, occurred at or beyond the stage of digestion. Purified protein (bovine gamma globulin) aggregates and homopolymer coacervates of poly-l-glutamic acid: poly-l-lysine were effective inducers of lysosomal acid phosphatase, beta-glucuronidase, and cathepsin D, whereas homopolymers of the same D-amino acids were ineffective as inducers. Both the quantity of phagocytized substrate and its rate of enzymatic hydrolysis appear to control the level and persistance of lysosomal hydrolases. PMID:4911552

  7. Relevance of induction of human drug-metabolizing enzymes: pharmacological and toxicological implications

    PubMed Central

    PARK, B. K.; KITTERINGHAM, N. R.; PIRMOHAMED, M.; TUCKER, G. T.

    1996-01-01

    1Human drug-metabolizing systems can be induced, or activated, by a large number of exogenous agents including drugs, alcohol, components in the diet and cigarette smoke, as well as by endogenous factors. 2Such perturbation of enzyme activity undoubtedly contributes to both intra- and inter-individual variation both with respect to the rate and route of metabolism for a particular drug. Induction may, in theory, either attenuate the pharmacological response or exacerbate the toxicity of a particular drug, or both. 3The clinical impact of enzyme induction will depend upon the number of different enzyme isoforms affected and the magnitude of the inductive response within an individual, and also on the therapeutic indices of the affected substrates. 4The toxicological implications will be determined either by any change in the route of metabolism, or by a disturbance of the balance between activation and detoxication processes, which may be isozyme selective. PMID:8799511

  8. Quantitative Site-Specific Phosphoproteomics of Trichoderma reesei Signaling Pathways upon Induction of Hydrolytic Enzyme Production.

    PubMed

    Nguyen, Elizabeth V; Imanishi, Susumu Y; Haapaniemi, Pekka; Yadav, Avinash; Saloheimo, Markku; Corthals, Garry L; Pakula, Tiina M

    2016-02-01

    The filamentous fungus Trichoderma reesei is used for industrial production of secreted enzymes including carbohydrate active enzymes, such as cellulases and hemicellulases. The production of many of these enzymes by T. reesei is influenced by the carbon source it grows on, where the regulation system controlling hydrolase genes involves various signaling pathways. T. reesei was cultivated in the presence of sorbitol, a carbon source that does not induce the production of cellulases and hemicellulases, and then exposed to either sophorose or spent-grain extract, which are efficient inducers of the enzyme production. Specific changes at phosphorylation sites were investigated in relation to the production of cellulases and hemicellulases using an MS-based framework. Proteome-wide phosphorylation following carbon source exchange was investigated in the early stages of induction: 0, 2, 5, and 10 min. The workflow involved sequential trypsin digestion, TiO2 enrichment, and MS analysis using a Q Exactive mass spectrometer. We report on the identification and quantitation of 1721 phosphorylation sites. Investigation of the data revealed a complex signaling network activated upon induction involving components related to light-mediated cellulase induction, osmoregulation, and carbon sensing. Changes in protein phosphorylation were detected in the glycolytic pathway, suggesting an inhibition of glucose catabolism at 10 min after the addition of sophorose and as early as 2 min after the addition of spent-grain extract. Differential phosphorylation of factors related to carbon storage, intracellular trafficking, cytoskeleton, and cellulase gene regulation were also observed. PMID:26689635

  9. Induction and inhibition of mouse cytochrome P-450 2B enzymes by musk xylene.

    PubMed

    Lehman-McKeeman, L D; Johnson, D R; Caudill, D

    1997-01-01

    Musk xylene (MX) (1,3,5-trinitro-2-t-butylxylene) is a nitromusk perfume ingredient that although uniformly negative in a battery of genotoxicity tests, produces a high incidence of liver tumors in mice. The purpose of this work was to characterize the profile and dose-response relationship of microsomal enzyme induction following exposure to MX. MX was dosed by gavage to male B6C3F1 mice for 7 days at 0, 1, 5, 10, 20, 50, 100, and 200 mg/kg after which microsomes were prepared. At 200 mg/kg, MX increased liver weight by about 65% and increased microsomal cytochrome P-450 content 2-fold over control. MX increased microsomal activity for O-dealkylation of 7-ethoxy and 7-methoxyresorufin 4- and 2-fold, respectively, and increased the N-demethylation of erythromycin approximately 2-fold. These results were generally consistent with increased CYP1A1, 1A2, and 3A protein levels determined by Western blotting. In contrast, whereas no increase in O-dealkylation of 7-pentoxyresorufin (PROD) was observed, MX treatment increased CYP2B protein levels about 25-fold over control at 200 mg/kg. Furthermore, a single dosage of MX (200 mg/kg) increased Cyp2b-10 mRNA to a maximal level and with a time course similar to phenobarbital (PB). To study inhibition of CYP2B enzymes in vivo, mice were treated with PB (0.05% in drinking water for 5 days), then given a single dosage of corn oil or MX (200 mg/kg) at 2 or 18 hr before necropsy. PB treatment increased PROD activity 25-fold, and at 2 hr after MX treatment (associated with peak plasma levels of MX), there was no change in the PB-induced PROD activity. However, at 18 hr, MX treatment decreased PROD activity by 90%. Despite the in vivo inhibition, in vitro studies indicated that MX did not cause mechanism-based inactivation of CYP2B enzymes. The potential for nitroreduction of MX (catalyzed by anaerobic intestinal bacteria) to contribute to the inhibition of CYP2B enzyme activity was evaluated in a separate group of PB-induced mice

  10. Oxygen-independent induction of enzyme activities related to oxygen metabolism in yeast by copper.

    PubMed

    Galiazzo, F; Schiesser, A; Rotilio, G

    1988-04-14

    Aerobic growth of Saccharomyces cerevisiae in the presence of CuSO4 (between 0.1 and 1 mM) caused a generalized induction of major enzyme activities involved in 'housekeeping' routes of oxygen metabolism (cytochrome oxidase, glutathione peroxidases and catalase) which were comparable to or higher than that observed with Cu,Zn-superoxide dismutase. Fumarase and glutathione transferase, tested as controls for oxygen-unrelated activities, were found to decrease under the same conditions. In the absence of oxygen, copper addition to yeast resulted in significant increases of Cu,Zn-superoxide dismutase and glutathione peroxidases and a slight increase of cytochrome oxidase, with catalase remaining undetectable irrespective of whether or not copper was present. Other metal ions tested (Mn2+, Co2+) were unable to produce such effects. It is concluded that copper has a general inducing effect on enzymes related to metabolism of oxygen and oxygen derivatives, which is mediated neither by formation of O2-. and H2O2 nor by interaction with copper-specific apoproteins. These results point to a general role of copper as regulator of the expression of major enzyme activities involved in biological oxygen activation. PMID:2831994

  11. Induction of salt tolerance in Azolla microphylla Kaulf through modulation of antioxidant enzymes and ion transport.

    PubMed

    Abraham, Gerard; Dhar, Dolly Wattal

    2010-09-01

    Azolla microphylla plants exposed directly to NaCl (13 dsm(-1)) did not survive the salinity treatment beyond a period of one day, whereas plants exposed directly to 4 and 9 dsm(-1) NaCl were able to grow and produce biomass. However, plants pre-exposed to NaCl (2 dsm(-1)) for 7 days on subsequent exposure to 13 dsm(-1) NaCl were able to grow and produce biomass although at a slow rate and are hereinafter designated as pre-exposed plants. The pre-exposed and directly exposed plants distinctly differed in their response to salt in terms of lipid peroxidation, proline accumulation, activity of antioxidant enzymes, such as SOD, APX, and CAT, and Na(+)/K(+) ratio. Efficient modulation of antioxidant enzymes coupled with regulation of ion transport play an important role in the induction of salt tolerance. Results show that it is possible to induce salt adaptation in A. microphylla by pre-exposing them to low concentrations of NaCl. PMID:20422236

  12. The chemopreventive effects of Saussurea salicifolia through induction of apoptosis and phase II detoxification enzyme.

    PubMed

    Kang, Kyungsu; Lee, Hee Ju; Kim, Chul Young; Lee, Saet Byoul; Tunsag, Jigjidsuren; Batsuren, Dulamjav; Nho, Chu Won

    2007-12-01

    The ethanol extract of the aerial part of the Mongolian medicinal plant Saussurea salicifolia induced a dose-dependent cell growth inhibition in both human gastric adenocarcinoma AGS cells and mouse hepatoma Hepa 1c1c7 cells (IC(50)=30.22 and 116.96 mug/ml), respectively. The extract induced an apoptosis in AGS cells inference from the externalization of the phosphatidylserine, the increase of the sub G0/G1 content (%) and the apoptotic morphological changes including membrane blebbing, the formation of apoptotic bodies and chromatin condensation. In order to identify active substances causing the apoptosis, we further isolated major compounds present in Saussurea salicifolia and 7 compounds were isolated including a sesquiterpene lactone, cynaropicrin, 3 lignans (trachelogenin, matairesinol and arctigenin) and 3 lignan glycosides (tracheloside, matairesinoside and arctiin). In general the lignan aglycones were more cytotoxic than their lignan glycosides in both AGS cells and Hepa 1c1c7 cells. Cynaropicrin not only showed the most potent cytotoxicity among the 7 major compounds but also it induced an apoptosis and a weak G2/M arrest in AGS cells. Arctigenin had the second-best cytotoxicity among 7 major compounds, and induced an apoptosis. In order to evaluate the induction of the phase II detoxification enzyme, we measured the induction of quinone reductase activity of the extract, fractions and compounds in Hepa 1c1c7 cells. The ethyl acetate fraction and arctigenin showed the strongest cancer chemopreventive activity (chemoprevention index=9.88 and 7.57, respectively). These data suggest that the extract as well as the lignan compounds (especially arctigenin) originated from Saussurea salicifolia may be served as potential cancer chemopreventive agents for prevention or treatment of human cancers. PMID:18057725

  13. Use of mRNA expression to detect the induction of drug metabolising enzymes in rat and human hepatocytes

    SciTech Connect

    Richert, L. Tuschl, G.; Pekthong, D.; Mantion, G.; Weber, J.-C.; Mueller, S.O.

    2009-02-15

    It is important to investigate the induction of cytochrome P450 (CYP) enzymes by drugs. The most relevant end point is enzyme activity; however, this requires many cells and is low throughput. We have compared the CYP1A, CYP2B and CYP3A induction response to eight inducers in rat and human hepatocytes using enzyme activities (CYP1A2 (ethoxyresorufin), 2B (benzoxyresorufin for rat and bupropion for human) and CYP3A (testosterone)) and Taqman{sup TM} Low Density Array (TLDA) analysis. There was a good correlation between the induction of CYP1A2, CYP2B6 and CYP3A4 enzyme activities and mRNA expression in human hepatocytes. In contrast, BROD activities and mRNA expression in rat hepatocytes correlated poorly. However, bupropion hydroxylation correlated well with Cyp2b1 expression in rat hepatocytes. TLDA analysis of a panel of mRNAs encoding for CYPs, phase 2 enzymes, nuclear receptors and transporters revealed that the main genes induced by the 8 compounds tested were the CYPs. AhR ligands also induced UDP-glucuronosyltransferases and glutathione S-transferases in rat and human hepatocytes. The transporters, MDR1, MDR3 and OATPA were the only transporter genes significantly up-regulated in human hepatocytes. In rat hepatocytes Bsep, Mdr2, Mrp2, Mrp3 and Oatp2 were up-regulated. We could then show a good in vivo:in vitro correlation in the induction response of isolated rat hepatocytes and ex-vivo hepatic microsomes for the drug development candidate, EMD392949. In conclusion, application of TLDA methodology to investigate the potential of compounds to induce enzymes in rat and human hepatocytes increases the throughput and information gained from one assay, without reducing the predictive capacity.

  14. Polychlorinated biphenyl (PCB) induction of CYP3A4 enzyme activity in healthy Faroese adults

    SciTech Connect

    Petersen, Maria Skaalum Halling, Jonrit; Damkier, Per; Nielsen, Flemming; Grandjean, Philippe; Weihe, Pal; Brosen, Kim

    2007-10-15

    The CYP3A4 enzyme is, along with other cytochrome P450 enzymes, involved in the metabolism of environmental pollutants and is highly inducible by these substances. A commercial polychlorinated biphenyl (PCB) mixture, 1,1,1,-trichloro-2-(o-chlorophenyl), 2-(p'-chlorophenyl)ethane (o,p'-DDT) and 1,1,-dichloro-2,2-bis (p-chlorophenyl)ethene (p,p'-DDE) are known to induce CYP3A4 activity through activation of nuclear receptors, such as the pregnane X receptor. However, this induction of CYP3A4 has not yet been investigated in humans. Thus, the aim of the study was to determine the variability of the CYP3A4 phenotype in regard to increased concentrations of PCBs and other persistent organohalogen pollutants (POPs) in healthy Faroese adults. In 310 randomly selected Faroese residents aged 18-60 years, the CYP3A4 activity was determined based on the urinary 6{beta}-hydroxycortisol/cortisol (6{beta}-OHC/FC) ratio. POP exposures were assessed by measuring their concentrations in serum lipid. The results showed a unimodal distribution of the 6{beta}-OHC/FC ratio with values ranging from 0.58 to 27.38. Women had a slightly higher 6{beta}-OHC/FC ratio than men (p = 0.07). Confounder-adjusted multiple regression analysis showed significant associations between 6{beta}-OHC/FC ratios and {sigma}PCB, PCB-TEQ and p,p'-DDE, o,p'-DDT and HCB, respectively, but the associations were statistically significant for men only.

  15. Molecular responses as indicators of marine pollution: DNA damage and enzyme induction in Limanda limanda and Asterias rubens

    SciTech Connect

    Everaarts, J.M.; Sleiderink, H.M.; Besten, P.J. den

    1994-12-01

    During a survey from 26 August through 13 September 1991, specimens of the flatfish, Limanda limanda (dab), and the asteroid echinoderm, Asterias rubens (seastar), were collected at sampling locations along transacts radiating into the North Sea from the coastal zone of The Netherlands. In homogenates of liver tissue from male dab and the digestive gland (pyloric caeca) of female seastar, DNA damage (strand breaks) and induction of the cytochrome P450-dependent monooxygenase system (MO) were determined. Areas could be described with significantly increased percentages of strand breaks (lower integrity) both in dab and seastar. However, enhanced DNA strand breaks did not correspond with contamination gradients, expressed as concentrations of polychlorinated biphenyls (PCBs) or polyaromatic hydrocarbons. MO enzyme induction in the hepatic 13,000g fraction of male dab, measured as 7-ethoxyresorufin-O-deethylase activity, was significantly enhanced in response to low ambient temperatures. Some evidence was found for the facilitation of benzo[a]pyrene hydroxylase activity expressing the enzyme induction in the microsomal fraction of pyloric caeca of seastars, at increasing PCB concentrations. DNA integrity and enzyme induction elucidate the physiologic status and might be indicative for ambient impairment within restricted areas, and not necessarily related to the presence of anthropogenic or xeno-biotic substances. 27 refs., 5 figs., 1 tab.

  16. Synergism of thyroid hormone and high carbohydrate diet in the induction of lipogenic enzymes in the rat. Mechanisms and implications.

    PubMed Central

    Mariash, C N; Kaiser, F E; Schwartz, H L; Towle, H C; Oppenheimer, J H

    1980-01-01

    We have investigated the relationship between the administration of triiodothyronine (T3) and a high carbohydrate (CHO) fat-free diet in the induction of lipogenic enzymes in two rat tissues, liver, and fat. Male thyroidectomized rats were treated with graded daily doses of T3 and either supplemented with a high CHO diet or left on a regular diet. Enzymes studied included malic enzyme (ME), fatty acid synthetase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase. In the liver, all four lipogenic enzymes showed a synergistic response between T3 administration and high CHO feeding. In fat, ME also responded synergistically. The interaction was reflected in an increased sensitivity to T3. The dose of T3 required to achieve 50% maximal response was reduced three- to seven-fold by the high CHO diet. This phenomenon could not be attributed to a dietary-induced alteration either in T3 metabolism or in number or affinity of the T3-nuclear receptors. Moreover, studies of the relative rate of synthesis of ME suggested a simultaneous time of onset in the induction of ME, within 2 h after the application of either T3 or CHO. Thus, it is unlikely that either stimulus is secondary to the other. Since parallel experiments from this laboratory (Towle, Mariash, and Oppenheimer,1980.Changes in hepatic levels of messenger ribonucleic acid for malic enzyme during induction by thyroid hormone or diet. Biochemistry. 19: 579-585.) show that ME induction both by CHO and T3 is mediated by an increase in specific messenger RNA for ME, the interaction of T3 and the dietary factor occurs at a pretanslational level. PMID:7364940

  17. Enzyme

    MedlinePlus

    Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For ... use them. Blood clotting is another example of enzymes at work. Enzymes are needed for all body ...

  18. Measurement of Human Cytochrome P450 Enzyme Induction Based on Mesalazine and Mosapride Citrate Treatments Using a Luminescent Assay.

    PubMed

    Kim, Young-Hoon; Bae, Young-Ji; Kim, Hyung Soo; Cha, Hey-Jin; Yun, Jae-Suk; Shin, Ji-Soon; Seong, Won-Keun; Lee, Yong-Moon; Han, Kyoung-Moon

    2015-09-01

    Drug metabolism mostly occurs in the liver. Cytochrome P450 (CYP) is a drug-metabolizing enzyme that is responsible for many important drug metabolism reactions. Recently, the US FDA and EU EMA have suggested that CYP enzyme induction can be measured by both enzymatic activity and mRNA expression. However, these experiments are time-consuming and their inter-assay variability can lead to misinterpretations of the results. To resolve these problems and establish a more powerful method to measure CYP induction, we determined CYP induction by using luminescent assay. Luminescent CYP assays link CYP enzyme activity to firefly luciferase luminescence technology. In this study, we measured the induction of CYP isozymes (1A2, 2B6, 2C9, and 3A4) in cryopreserved human hepatocytes (HMC424, 478, and 493) using a luminometer. We then examined the potential induction abilities (unknown so far) of mesalazine, a drug for colitis, and mosapride citrate, which is used as an antispasmodic drug. The results showed that mesalazine promotes CYP2B6 and 3A4 activities, while mosapride citrate promotes CYP1A2, 2B6, and 3A4 activities. Luminescent CYP assays offer rapid and safe advantages over LC-MS/MS and qRT-PCR methods. Furthermore, luminescent CYP assays decrease the interference between the optical properties of the test compound and the CYP substrates. Therefore, luminescent CYP assays are less labor intensive, rapid, and can be used as robust tools for high-throughput CYP screening during early drug discovery. PMID:26336590

  19. The role of carbon starvation in the induction of enzymes that degrade plant-derived carbohydrates in Aspergillus niger

    PubMed Central

    van Munster, Jolanda M.; Daly, Paul; Delmas, Stéphane; Pullan, Steven T.; Blythe, Martin J.; Malla, Sunir; Kokolski, Matthew; Noltorp, Emelie C.M.; Wennberg, Kristin; Fetherston, Richard; Beniston, Richard; Yu, Xiaolan; Dupree, Paul; Archer, David B.

    2014-01-01

    Fungi are an important source of enzymes for saccharification of plant polysaccharides and production of biofuels. Understanding of the regulation and induction of expression of genes encoding these enzymes is still incomplete. To explore the induction mechanism, we analysed the response of the industrially important fungus Aspergillus niger to wheat straw, with a focus on events occurring shortly after exposure to the substrate. RNA sequencing showed that the transcriptional response after 6 h of exposure to wheat straw was very different from the response at 24 h of exposure to the same substrate. For example, less than half of the genes encoding carbohydrate active enzymes that were induced after 24 h of exposure to wheat straw, were also induced after 6 h exposure. Importantly, over a third of the genes induced after 6 h of exposure to wheat straw were also induced during 6 h of carbon starvation, indicating that carbon starvation is probably an important factor in the early response to wheat straw. The up-regulation of the expression of a high number of genes encoding CAZymes that are active on plant-derived carbohydrates during early carbon starvation suggests that these enzymes could be involved in a scouting role during starvation, releasing inducing sugars from complex plant polysaccharides. We show, using proteomics, that carbon-starved cultures indeed release CAZymes with predicted activity on plant polysaccharides. Analysis of the enzymatic activity and the reaction products, indicates that these proteins are enzymes that can degrade various plant polysaccharides to generate both known, as well as potentially new, inducers of CAZymes. PMID:24792495

  20. Induction of Arabidopsis tryptophan pathway enzymes and camalexin by amino acid starvation, oxidative stress, and an abiotic elicitor.

    PubMed Central

    Zhao, J; Williams, C C; Last, R L

    1998-01-01

    The tryptophan (Trp) biosynthetic pathway leads to the production of many secondary metabolites with diverse functions, and its regulation is predicted to respond to the needs for both protein synthesis and secondary metabolism. We have tested the response of the Trp pathway enzymes and three other amino acid biosynthetic enzymes to starvation for aromatic amino acids, branched-chain amino acids, or methionine. The Trp pathway enzymes and cytosolic glutamine synthetase were induced under all of the amino acid starvation test conditions, whereas methionine synthase and acetolactate synthase were not. The mRNAs for two stress-inducible enzymes unrelated to amino acid biosynthesis and accumulation of the indolic phytoalexin camalexin were also induced by amino acid starvation. These results suggest that regulation of the Trp pathway enzymes under amino acid deprivation conditions is largely a stress response to allow for increased biosynthesis of secondary metabolites. Consistent with this hypothesis, treatments with the oxidative stress-inducing herbicide acifluorfen and the abiotic elicitor alpha-amino butyric acid induced responses similar to those induced by the amino acid starvation treatments. The role of salicylic acid in herbicide-mediated Trp and camalexin induction was investigated. PMID:9501110

  1. Applying theories of microbial metabolism for induction of targeted enzyme activity in a methanogenic microbial community at a metabolic steady state.

    PubMed

    Speda, Jutta; Johansson, Mikaela A; Jonsson, Bengt-Harald; Karlsson, Martin

    2016-09-01

    Novel enzymes that are stable in diverse conditions are intensively sought because they offer major potential advantages in industrial biotechnology, and microorganisms in extreme environments are key sources of such enzymes. However, most potentially valuable enzymes are currently inaccessible due to the pure culturing problem of microorganisms. Novel metagenomic and metaproteomic techniques that circumvent the need for pure cultures have theoretically provided possibilities to identify all genes and all proteins in microbial communities, but these techniques have not been widely used to directly identify specific enzymes because they generate vast amounts of extraneous data.In a first step towards developing a metaproteomic approach to pinpoint targeted extracellular hydrolytic enzymes of choice in microbial communities, we have generated and analyzed the necessary conditions for such an approach by the use of a methanogenic microbial community maintained on a chemically defined medium. The results show that a metabolic steady state of the microbial community could be reached, at which the expression of the targeted hydrolytic enzymes were suppressed, and that upon enzyme induction a distinct increase in the targeted enzyme expression was obtained. Furthermore, no cross talk in expression was detected between the two focal types of enzyme activities under their respective inductive conditions. Thus, the described approach should be useful to generate ideal samples, collected before and after selective induction, in controlled microbial communities to clearly discriminate between constituently expressed proteins and extracellular hydrolytic enzymes that are specifically induced, thereby reducing the analysis to only those proteins that are distinctively up-regulated. PMID:27115757

  2. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    NASA Astrophysics Data System (ADS)

    Semsang, Nuananong; Yu, LiangDeng

    2013-07-01

    Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  3. A QUANTITATIVE MODEL FOR XENOBIOTIC METABOLIZING ENZYME (XME) INDUCTION REGULATED BY THE PREGNANE X RECEPTOR (PXR)

    EPA Science Inventory

    The nuclear receptor, PXR, is an integral part of the regulation of hepatic metabolism. It has been shown to regulate specific CYPs (phase I drug-metabolizing enzymes) as well as certain phase II drug metabolism activities, including UDP-glucuronosyl transferase (UGT), sulfotran...

  4. Glutathione peroxidase in yeast. Presence of the enzyme and induction by oxidative conditions.

    PubMed

    Galiazzo, F; Schiesser, A; Rotilio, G

    1987-09-30

    The presence of glutathione peroxidase activity is reported for the first time for a wild type strain of Saccharomyces cerevisiae. Both forms of enzyme, i.e. that specifically active toward H2O2 alone and that decomposing also organic peroxides, were found to be present. The H2O2 specific form disappeared when cells were grown in the absence of oxygen, while the other form was much increased under the same conditions. Addition of copper to the culture greatly increased both forms. The results show that glutathione peroxidase is to be included, as an important component that is also highly responsive to oxidative environments, in the enzyme defense system of yeast against oxidative damage. PMID:3311044

  5. [Steroid-transforming enzymes from microorganisms. XII. Induction characteristics of the 4-en-3-oxosteroid: (acceptor)-1-en-oxidoreductase in Nocardia opaca].

    PubMed

    Hörhold, C; Hüller, E; Rose, G

    1979-01-01

    17 alpha-Methyltestosterone and the corresponding 1(2)-dehydrocompound (Dianabol) are efficient inducers of the 4-en-3-oxosteroid: (acceptor)-1-en-oxidoreductase from Nocardia opaca. After a lag period of 4 hours the enzyme activity increases rapidly. During the induction the steroids are completely metabolized causing a drastical drop of specific enzyme activity. Using a fixed induction time the optimal steroid concentration and the temperature characteristic were found out. The influence of the concentration of the steroid water suspension on the induction effect is discussed to be dependent on the velocity of the dissolving of the steroid particles. Chloramphenicol and streptomycin are powerful inhibitors of the induction process. PMID:547499

  6. Enzymes of anaerobic ethylbenzene and p-ethylphenol catabolism in 'Aromatoleum aromaticum': differentiation and differential induction.

    PubMed

    Muhr, Enrico; Schühle, Karola; Clermont, Lina; Sünwoldt, Katharina; Kleinsorge, Daniel; Seyhan, Deniz; Kahnt, Jörg; Schall, Iris; Cordero, Paul R; Schmitt, Georg; Heider, Johann

    2015-11-01

    The denitrifying bacterium 'Aromatoleum aromaticum' strain EbN1 is one of the best characterized bacteria regarding anaerobic ethylbenzene degradation. EbN1 also degrades various other aromatic and phenolic compounds in the absence of oxygen, one of them being p-ethylphenol. Despite having similar chemical structures, ethylbenzene and p-ethylphenol have been proposed to be metabolized by completely separate pathways. In this study, we established and applied biochemical and molecular biological methods to show the (almost) exclusive presence and specificity of enzymes involved in the respective degradation pathways by recording enzyme activities, complemented by heme staining, immuno- and biotin-blotting analyses. These combined results substantiated the predicted p-ethylphenol degradation pathway. The identified enzymes include a heme c-containing p-ethylphenol-hydroxylase, both an (R)- and an (S)-specific alcohol dehydrogenase as well as a novel biotin-dependent carboxylase. We also establish an activity assay for benzoylacetate-CoA ligases likely being involved in both metabolic pathways. PMID:26275558

  7. Alpha Adrenergic Induction of Transport of Lysosomal Enzyme across the Blood-Brain Barrier

    PubMed Central

    Urayama, Akihiko; Dohgu, Shinya; Robinson, Sandra M.; Sly, William S.; Grubb, Jeffery H.; Banks, William A

    2015-01-01

    The impermeability of the adult blood-brain barrier (BBB) to lysosomal enzymes impedes the ability to treat the central nervous system manifestations of lysosomal storage diseases. Here, we found that simultaneous stimulation of the alpha1 and alpha2 adrenoreceptor restores in adult mice the high rate of transport for the lysosomal enzyme P-GUS that is seen in neonates but lost with development. Beta adrenergics, other monoamines, and acetylcholine did not restore this transport. A high dose (500 microg/mouse) of clonidine, a strong alpha2 and weak alpha1 agonist, was able to act as monotherapy in the stimulation of P-GUS transport. Neither use of alpha1 plus alpha2 agonists nor the high dose clonidine disrupted the BBB to albumin. In situ brain perfusion and immunohistochemistry studies indicated that adrengerics act on transporters already at the luminal surface of brain endothelial cells. These results show that adrenergic stimulation, including monotherapy with clonidine, could be key for CNS enzyme replacement therapy. PMID:26545208

  8. Application of Micropatterned Cocultured Hepatocytes to Evaluate the Inductive Potential and Degradation Rate of Major Xenobiotic Metabolizing Enzymes.

    PubMed

    Dixit, Vaishali; Moore, Amanda; Tsao, Hong; Hariparsad, Niresh

    2016-02-01

    Long-term coculture models of hepatocytes are promising tools to study drug transport, clearance, and hepatoxicity. In this report we compare the basal expression of drug disposition genes and the inductive response of prototypical inducers (rifampin, phenobarbital, phenytoin) in hepatocyte two-dimensional monocultures and the long-term coculture model (HepatoPac). All the inducers used in the study increased the expression and activity of CYP3A4, CYP2B6 and CYP2C enzymes in the HepatoPac cultures. The coculture model showed a consistent and higher induction of CYP2C enzymes compared with the monocultures. The EC50 of rifampin for CYP3A4 and CYP2C9 was up to 10-fold lower in HepatoPac than the monocultures. The EC50 of rifampin calculated from the clinical drug interaction studies correlated well with the EC50 observed in the HepatoPac cultures. Owing to the long-term stability of the HepatoPac cultures, we were able to directly measure a half-life (t1/2) for both CYP3A4 and CYP2B6 using the depletion kinetics of mRNA and functional activity. The t1/2 for CYP3A4 mRNA was 26 hours and that for the functional protein was 49 hours. The t1/2 of CYP2B6 was 38 hours (mRNA) and 68 hours (activity), which is longer than CYP3A4 and shows the differential turnover of these two proteins. This is the first study to our knowledge to report the turnover rate of CYP2B6 in human hepatocytes. The data presented here demonstrate that the HepatoPac cultures have the potential to be used in long-term culture to mimic complex clinical scenarios. PMID:26658225

  9. Immune response to enzyme replacement therapies in lysosomal storage diseases and the role of immune tolerance induction.

    PubMed

    Kishnani, Priya S; Dickson, Patricia I; Muldowney, Laurie; Lee, Jessica J; Rosenberg, Amy; Abichandani, Rekha; Bluestone, Jeffrey A; Burton, Barbara K; Dewey, Maureen; Freitas, Alexandra; Gavin, Derek; Griebel, Donna; Hogan, Melissa; Holland, Stephen; Tanpaiboon, Pranoot; Turka, Laurence A; Utz, Jeanine J; Wang, Yow-Ming; Whitley, Chester B; Kazi, Zoheb B; Pariser, Anne R

    2016-02-01

    The US Food and Drug Administration (FDA) and National Organization for Rare Disease (NORD) convened a public workshop titled "Immune Responses to Enzyme Replacement Therapies: Role of Immune Tolerance Induction" to discuss the impact of anti-drug antibodies (ADAs) on efficacy and safety of enzyme replacement therapies (ERTs) intended to treat patients with lysosomal storage diseases (LSDs). Participants in the workshop included FDA staff, clinicians, scientists, patients, industry, and advocacy group representatives. The risks and benefits of implementing prophylactic immune tolerance induction (ITI) to reduce the potential clinical impact of antibody development were considered. Complications due to immune responses to ERT are being recognized with increasing experience and lengths of exposure to ERTs to treat several LSDs. Strategies to mitigate immune responses and to optimize therapies are needed. Discussions during the workshop resulted in the identification of knowledge gaps and future areas of research, as well as the following proposals from the participants: (1) systematic collection of longitudinal data on immunogenicity to better understand the impact of ADAs on long-term clinical outcomes; (2) development of disease-specific biomarkers and outcome measures to assess the effect of ADAs and ITI on efficacy and safety; (3) development of consistent approaches to ADA assays to allow comparisons of immunogenicity data across different products and disease groups, and to expedite reporting of results; (4) establishment of a system to widely share data on antibody titers following treatment with ERTs; (5) identification of components of the protein that are immunogenic so that triggers and components of the immune responses can be targeted in ITI; and (6) consideration of early ITI in patients who are at risk of developing clinically relevant ADA that have been demonstrated to worsen treatment outcomes. PMID:26597321

  10. Induction of the expressions of antioxidant enzymes by luteinizing hormone in the bovine corpus luteum.

    PubMed

    Kawaguchi, Syota; Sakumoto, Ryosuke; Okuda, Kiyoshi

    2013-01-01

    Luteoprotective mechanisms of luteinizing hormone (LH) involved in the maintenance of bovine corpus luteum (CL) function have not been completely clarified. Since antioxidant enzymes are well documented as antiapoptotic factors in the CL of many mammals, we hypothesized that the luteoprotective action of LH is mediated by stimulating the local production and action of antioxidant enzymes. To test the above hypothesis, in the present study, we examined the mechanisms involved in the luteoprotective actions of LH. Cultured bovine luteal cells obtained from the CL at the mid-luteal stage (days 8-12 of the estrous cycle) were treated with LH (10 ng/ml), onapristone (OP; a specific progesterone receptor antagonist, 100 μM) and diethyldithiocarbamate [DETC; an inhibitor of superoxide dismutase (SOD), 100 μM] for 24 h. LH in combination with or without OP significantly increased the mRNA and protein expressions of manganese SOD (Mn-SOD) and catalase (CATA) and SOD activity. While LH alone significantly increased the mRNA and protein expressions of SOD containing copper and zinc (Cu,Zn-SOD), OP in combination with or without LH significantly decreased the mRNA and protein expressions of Cu,Zn-SOD. In addition, Cu,Zn-SOD, Mn-SOD and CATA mRNA expressions were higher at the mid luteal phase than the other luteal phases. LH in combination with DETC significantly decreased LH-increased cell viability. The overall results suggest that LH increases cell viability by LH-increased antioxidant enzymes, resulting in maintenance of CL function during the luteal phase in cattle. PMID:23386101

  11. A bleached-kraft mill effluent fraction causing induction of a fish mixed-function oxygenase enzyme

    SciTech Connect

    Burnison, B.K.; Hodson, P.V.; Nuttley, D.J.; Efler, S.

    1996-09-01

    Pulp mill effluents contain a myriad of chemicals that have the potential to cause deleterious effects on aquatic biota in receiving waters. Some of these chemicals evoke an acute lethal response of exposed biota while others evoke sublethal responses. One such sublethal response is the induction of mixed-function oxygenases (MFO) in fish, specifically the CYP1A1 enzyme ethoxy-resorufin-o-deethylase (EROD). Compounds causing MFO induction include congeners of polychlorinated biphenyls (PCBs), dioxins, furans, and polycyclic aromatic hydrocarbons (PAHs). The authors followed the partitioning of the inducing chemicals in pulp mill effluent fractions by Toxicity Identification Evaluation (TIE), or bioassay-driven chemical analysis. This procedure was eventually modified to a more direct technique involving centrifugation, filtration, cleanup procedures, and C{sub 18} solid-phase adsorption. The extracts from the fractionation of two pulp mill effluents after secondary treatment were tested for EROD-inducing activity in a 4-d rainbow trout bioassay. The methanol extracts of particulates/colloids showed significant inducing capacity in Mill A effluent but not in Mill B effluent. The C{sub 18} methanol extracts induced activity from both effluents, with extracts from Mill A causing the greatest response. The particulate/colloidal extract (Mill A) was used as the source material for chemicals which caused EROD induction. The fraction was purified by solid-phase extraction techniques and reverse-phase high-performance liquid chromatography. The majority of the EROD activity was found in the moderately nonpolar region of the chromatogram (K{sub ow} = 4.6 to 5.1).

  12. Phase II enzyme induction by a carotenoid, lutein, in a PC12D neuronal cell line

    SciTech Connect

    Miyake, Seiji; Kobayashi, Saori; Tsubota, Kazuo; Ozawa, Yoko

    2014-04-04

    Highlights: • Lutein reduced ROS levels in a PC12D neuronal cell line. • Lutein induced mRNAs of phase II antioxidative enzymes in PC12D neuronal cells. • Lutein increased protein levels of HO-1, SOD2, and NQO-1 in PC12D neuronal cells. • Lutein had no effect on intranuclear Nrf2 levels in PC12D neuronal cells. • Lutein did not activate potential upstream Nrf2 nuclear translocation pathways. - Abstract: The mechanism by which lutein, a carotenoid, acts as an antioxidant in retinal cells is still not fully understood. Here, lutein treatment of a neuronal cell line (PC12D) immediately resulted in reduced intracellular ROS levels, implying that it has a direct role in ROS scavenging. Significantly, lutein treatment also induced phase II antioxidative enzyme expression, probably via a nuclear factor-like 2 (Nrf2) independent pathway. This latter mechanism could explain why lutein acts diversely to protect against oxidative/cytotoxic stress, and why it is physiologically involved in the human neural tissue, such as the retina.

  13. Evidence for a complex of three beta-oxidation enzymes in Escherichia coli: induction and localization.

    PubMed Central

    O'Brien, W J; Frerman, F E

    1977-01-01

    The enzymes for beta-oxidation of fatty acids in inducible and constitutive strains of Escherichia coli were assayed in soluble and membrane fractions of disrupted cells by using fatty acid and acyl-coenzyme A (CoA) substrates containing either 4 or 16 carbon atoms in the acyl moieties. Cell fractionation was monitored, using succinic dehydrogenase as a membrane marker and glucose 6-phosphate dehydrogenase as a soluble marker. Acyl-CoA synthetase activity was detected exclusively in the membrane fraction, whereas acyl-CoA dehydrogenase, 3-hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase activities that utilized both C4 and C16 acyl-CoA substrates were isolated from the soluble fraction. 3-Hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase activities assayed with both C4 and C16 acyl-CoA substrates co-chromatographed on gel filtration and ion-exchange columns and cosedimented in glycerol gradients. The data show that these three enzyme activities of the fad regulon can be isolated as a multienzyme complex. This complex dissociates in very dilute preparations; however, in those preparations where the three activities are separated, the fractionated species retain activity with both C4 and C16 acyl-CoA substrates. PMID:334745

  14. Hemolytic anemia and induction of phase II detoxification enzymes by diprop-1-enyl sulfide in rats: dose-response study.

    PubMed

    Munday, Rex; Munday, Christine M; Munday, John S

    2005-12-14

    Epidemiological evidence indicates that a high dietary intake of plants of the Allium family, such as garlic and onions, is associated with a decreased risk of cancer in humans. It has been suggested that this chemopreventative effect involves the ability of the aliphatic sulfides derived from these vegetables to increase tissue activities of phase II detoxification enzymes. Several highly effective inducers from garlic have been identified, but most of the previously studied compounds from onion have proved to be only weakly active. In the present study, the inductive activity of another onion-derived sulfide, diprop-1-enyl sulfide, has been investigated. This substance was a potent inducer of phase II enzymes in rats, showing significant effects in the lungs and in the lower part of the gastrointestinal tract, suggesting that diprop-1-enyl sulfide could be a useful chemopreventative agent at these sites. At high dose levels, diprop-1-enyl sulfide caused hemolytic anemia, which may be due to in vivo conversion of the sulfide to active metabolites. PMID:16332117

  15. The induction of two biosynthetic enzymes helps Escherichia coli sustain heme synthesis and activate catalase during hydrogen peroxide stress

    PubMed Central

    Mancini, Stefano; Imlay, James A.

    2015-01-01

    Summary Hydrogen peroxide pervades many natural environments, including the phagosomes that mediate cell-based immunity. Transcriptomic analysis showed that during protracted low-grade H2O2 stress, Escherichia coli responds by activating both the OxyR defensive regulon and the Fur iron-starvation response. OxyR induced synthesis of two members of the nine-step heme biosynthetic pathway: ferrochelatase (HemH) and an isozyme of coproporphyrinogen III oxidase (HemF). Mutations that blocked either adaptation caused the accumulation of porphyrin intermediates, inadequate activation of heme enzymes, low catalase activity, defective clearance of H2O2, and a failure to grow. Genetic analysis indicated that HemH induction is needed to compensate for iron sequestration by the mini-ferritin Dps. Dps activity protects DNA and proteins by limiting Fenton chemistry, but it interferes with the ability of HemH to acquire the iron that it needs to complete heme synthesis. HemF is a manganoprotein that displaces HemN, an iron-sulfur enzyme whose synthesis and/or stability is apparently problematic during H2O2 stress. Thus the primary responses to H2O2, including the sequestration of iron, require compensatory adjustments in the mechanisms of iron-cofactor synthesis. The results support the growing evidence that oxidative stress is primarily an iron pathology. PMID:25664592

  16. Induction by xenobiotics of phase I and phase II enzyme activities in the human keratinocyte cell line NCTC 2544.

    PubMed

    Gelardi, A; Morini, F; Dusatti, F; Penco, S; Ferro, M

    2001-12-01

    This study analyses the expression and induction of several drug-metabolising enzyme activities involved in either phase I or phase II biotransformations in NCTC 2544 human keratinocytes. The phase I activities 7-ethoxycoumarin O-deethylase (ECOD), 7-ethoxyresorufin O-deethylase (EROD) and 7-pentoxyresorufin O-depenthylase (PROD) were easily detectable in basal conditions. During incubations lasting up to 144 h in the presence of the classical cytochrome P450 inducers beta-naphthoflavone (BNF), 3-methylcholanthrene (MC) and phenobarbital (PB), a considerable and significant increase in all the three activities was observed. PROD activity was induced up to 4.5-fold after 96 h in the presence of PB. The MC-induced ECOD and EROD activities were also dose-dependently inhibited by alpha-naphothflavone, which was given to the cells during the incubation with CYP 1A1 inducers. Also the PB-induced PROD activity was decreased by the simultaneous addition of the CYP 2B inhibitor metyrapone. Both cytochrome P450 inhibitors were used at non-cytotoxic concentrations. The phase II enzymes glutathione S-transferase, aldehyde dehydrogenase and quinone reductase were all highly expressed and inducible by MC. The exposure (24 h) of the cells to four hair dyes used in cosmetic formulations resulted in a marked increase in ECOD activity. All data give sustained evidence for the suitability of NCTC 2544 cell line to skin toxicology studies. PMID:11698172

  17. Phenobarbital mechanistic data and risk assessment: enzyme induction, enhanced cell proliferation, and tumor promotion.

    PubMed

    Whysner, J; Ross, P M; Williams, G M

    1996-01-01

    Chronic exposure to high doses of phenobarbital (PB) causes hepatocellular adenomas in both mice and rats and hepatocellular carcinomas in some strains of mice. Long-term PB therapy has not been found to cause human tumors. PB is not DNA reactive, and most genotoxicity tests have yielded negative results. PB has been extensively studied as an epigenetic, rodent liver tumor promoter. At exposures causing rodent liver tumors, PB has measurable effects on hepatocytes: PB inhibits cell-to-cell communication; PB induces enzymes, including P450 cytochromes; PB stimulates proliferation and inhibits apoptosis of hepatocytes in neoplastic foci. Threshold exposures for some of these endpoints coincide with the threshold exposure for tumorigenesis. PMID:8910954

  18. Enhanced response to enzyme replacement therapy in Pompe disease after the induction of immune tolerance.

    PubMed

    Sun, Baodong; Bird, Andrew; Young, Sarah P; Kishnani, Priya S; Chen, Y-T; Koeberl, Dwight D

    2007-11-01

    Pompe disease, which results from mutations in the gene encoding the glycogen-degrading lysosomal enzyme acid alpha -glucosidase (GAA) (also called "acid maltase"), causes death in early childhood related to glycogen accumulation in striated muscle and an accompanying infantile-onset cardiomyopathy. The efficacy of enzyme replacement therapy (ERT) with recombinant human GAA was demonstrated during clinical trials that prolonged subjects' overall survival, prolonged ventilator-free survival, and also improved cardiomyopathy, which led to broad-label approval by the U.S. Food and Drug Administration. Patients who lack any residual GAA expression and are deemed negative for cross-reacting immunologic material (CRIM) have a poor response to ERT. We previously showed that gene therapy with an adeno-associated virus (AAV) vector containing a liver-specific promoter elevated the GAA activity in plasma and prevented anti-GAA antibody formation in immunocompetent GAA-knockout mice for 18 wk, predicting that liver-specific expression of human GAA with the AAV vector would induce immune tolerance and enhance the efficacy of ERT. In this study, a very low number of AAV vector particles was administered before initiation of ERT, to prevent the antibody response in GAA-knockout mice. A robust antibody response was provoked in naive GAA-knockout mice by 6 wk after a challenge with human GAA and Freund's adjuvant; in contrast, administration of the AAV vector before the GAA challenge prevented the antibody response. Most compellingly, the antibody response was prevented by AAV vector administration during the 12 wk of ERT, and the efficacy of ERT was thereby enhanced. Thus, AAV vector-mediated gene therapy induced a tolerance to introduced GAA, and this strategy could enhance the efficacy of ERT in CRIM-negative patients with Pompe disease and in patients with other lysosomal storage diseases. PMID:17924344

  19. Enhanced Response to Enzyme Replacement Therapy in Pompe Disease after the Induction of Immune Tolerance

    PubMed Central

    Sun, Baodong ; Bird, Andrew ; Young, Sarah P. ; Kishnani, Priya S. ; Chen, Y.-T. ; Koeberl, Dwight D. 

    2007-01-01

    Pompe disease, which results from mutations in the gene encoding the glycogen-degrading lysosomal enzyme acid α-glucosidase (GAA) (also called “acid maltase”), causes death in early childhood related to glycogen accumulation in striated muscle and an accompanying infantile-onset cardiomyopathy. The efficacy of enzyme replacement therapy (ERT) with recombinant human GAA was demonstrated during clinical trials that prolonged subjects’ overall survival, prolonged ventilator-free survival, and also improved cardiomyopathy, which led to broad-label approval by the U.S. Food and Drug Administration. Patients who lack any residual GAA expression and are deemed negative for cross-reacting immunologic material (CRIM) have a poor response to ERT. We previously showed that gene therapy with an adeno-associated virus (AAV) vector containing a liver-specific promoter elevated the GAA activity in plasma and prevented anti-GAA antibody formation in immunocompetent GAA-knockout mice for 18 wk, predicting that liver-specific expression of human GAA with the AAV vector would induce immune tolerance and enhance the efficacy of ERT. In this study, a very low number of AAV vector particles was administered before initiation of ERT, to prevent the antibody response in GAA-knockout mice. A robust antibody response was provoked in naive GAA-knockout mice by 6 wk after a challenge with human GAA and Freund’s adjuvant; in contrast, administration of the AAV vector before the GAA challenge prevented the antibody response. Most compellingly, the antibody response was prevented by AAV vector administration during the 12 wk of ERT, and the efficacy of ERT was thereby enhanced. Thus, AAV vector–mediated gene therapy induced a tolerance to introduced GAA, and this strategy could enhance the efficacy of ERT in CRIM-negative patients with Pompe disease and in patients with other lysosomal storage diseases. PMID:17924344

  20. Induction of protease release of the resistant diatom Chaetoceros didymus in response to lytic enzymes from an algicidal bacterium.

    PubMed

    Paul, Carsten; Pohnert, Georg

    2013-01-01

    Marine lytic bacteria can have a substantial effect on phytoplankton and are even capable to terminate blooms of microalgae. The bacterium Kordia algicida was reported to lyse cells of the diatom Skeletonema costatum and several other diatoms by a quorum sensing controlled excretion of proteases. However the diatom Chaetoceros didymus is fully resistant against the bacterial enzymes. We show that the growth curve of this diatom is essentially unaffected by addition of bacterial filtrates that are active against other diatoms. By monitoring proteases from the medium using zymography and fluorescence based activity assays we demonstrate that C. didymus responds to the presence of the lytic bacteria with the induced production of algal proteases. These proteases exhibit a substantially increased activity compared to the bacterial counterparts. The induction is also triggered by signals in the supernatant of a K. algicida culture. Size fractionation shows that only the >30 kD fraction of the bacterial exudates acts as an inducing cue. Implications for a potential induced defense of the diatom C. didymus are discussed. PMID:23469204

  1. Relative potency based on hepatic enzyme induction predicts immunosuppressive effects of a mixture of PCDDS/PCDFS and PCBS

    SciTech Connect

    Smialowicz, R.J.; DeVito, M.J. Williams, W.C.; Birnbaum, L.S.

    2008-03-15

    The toxic equivalency factor (TEF) approach was employed to compare immunotoxic potency of mixtures containing polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), using the antibody response to sheep erythrocytes (SRBC). Mixture-1 (MIX-1) contained TCDD, 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), 1,2,3,7,8-pentachlorodibenzofuran (1-PeCDF), 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF), and 1,2,3,4,6,7,8,9-octachlorodibenzofuran (OCDF). Mixture-2 (MIX-2) contained MIX-1 and the following PCBs, 3,3',4,4'-tetrachlorobiphenyl (IUPAC No. 77), 3,3',4,4',5-pentachlorobiphenyl (126), 3,3',4,4',5,5N-hexachlorobiphenyl (169), 2,3,3',4,4'-pentachlorobiphenyl (105), 2,3',4,4',5-pentachlorobiphenyl (118), and 2,3,3',4,4',5-hexachlorobiphenyl (156). The mixture compositions were based on relative chemical concentrations in food and human tissues. TCDD equivalents (TEQ) of the mixture were estimated using relative potency factors from hepatic enzyme induction in mice [DeVito, M.J., Diliberto, J.J., Ross, D.G., Menache, M.G., Birnbaum, L.S., 1997. Dose-response relationships for polyhalogenated dioxins and dibenzofurans following subchronic treatment in mice. I .CYP1A1 and CYP1A2 enzyme activity in liver, lung and skin. Toxicol. Appl. Pharmacol. 130, 197-208; DeVito, M.J., Menache, G., Diliberto, J.J., Ross, D.G., Birnbaum L.S., 2000. Dose-response relationships for induction of CYP1A1 and CYP1A2 enzyme activity in liver, lung, and skin in female mice following subchronic exposure to polychlorinated biphenyls. Toxicol. Appl. Pharmacol. 167, 157-172] Female mice received 0, 1.5, 15, 150 or 450 ng TCDD/kg/day or approximately 0, 1.5, 15, 150 or 450 ng TEQ/kg/day of MIX-1 or MIX-2 by gavage 5 days per week for 13 weeks. Mice were immunized 3 days after the last exposure and 4 days later, body, spleen, thymus, and liver weights were measured

  2. Dose of Phenobarbital and Age of Treatment at Early Life are Two Key Factors for the Persistent Induction of Cytochrome P450 Enzymes in Adult Mouse Liver.

    PubMed

    Tien, Yun-Chen; Liu, Ke; Pope, Chad; Wang, Pengcheng; Ma, Xiaochao; Zhong, Xiao-bo

    2015-12-01

    Drug treatment of neonates and infants and its long-term consequences on drug responses have emerged in recent years as a major challenge for health care professionals. In the current study, we use phenobarbital as a model drug and mouse as an in vivo model to demonstrate that the dose of phenobarbital and age of treatment are two key factors for the persistent induction of gene expression and consequential increases of enzyme activities of Cyp2b, Cyp2c, and Cyp3a in adult livers. We show that phenobarbital treatment at early life of day 5 after birth with a low dose (<100 mg/kg) does not change expression and enzyme activities of Cyp2b, Cyp2c, and Cyp3a in adult mouse liver, whereas phenobarbital treatment with a high dose (>200 mg/kg) significantly increases expression and enzyme activities of these P450s in adult liver. We also demonstrate that phenobarbital treatment before day 10 after birth, but not at later ages, significantly increases mRNAs, proteins, and enzyme activities of the tested P450s. Such persistent induction of P450 gene expression and enzyme activities in adult livers by phenobarbital treatment only occurs within a sensitive age window early in life. The persistent induction in gene expression and enzyme activities is higher in female mice than in male mice for Cyp2b10 but not for Cyp2c29 and Cyp3a11. These results will stimulate studies to evaluate the long-term impacts of drug treatment with different doses at neonatal and infant ages on drug metabolism, therapeutic efficacy, and drug-induced toxicity throughout the rest of life. PMID:26400395

  3. Correlation between mixed-function oxidase enzyme induction and aflatoxin B1-induced unscheduled DNA synthesis in the chick embryo, in vivo.

    PubMed

    Hamilton, J W; Bloom, S E

    1984-01-01

    The unscheduled DNA synthesis (UDS) technique has been adapted for use in the chick embryo, in vivo, to determine the relationship between induction of the mixed-function oxidase (MFO) enzyme system and genetic damage from an indirect-acting mutagen-carcinogen. Embryos were injected at 6 days of incubation (DI) with either phenobarbital (PB), a specific inducer of P-450-associated enzyme activities, or 3,4,3',4'-tetrachlorobiphenyl (TCB), a specific inducer of P1-450-associated enzyme activities. Aflatoxin B1 (AFB1) was injected 24 hr later (7 DI), followed by a 5-hr continuous 3H-thymidine exposure. The livers were removed, prepared for autoradiography, and hepatocytes were scored for an increase in grains/nucleus, indicative of UDS. Aflatoxin B1 caused a dose-related increase in UDS in all control and induction groups. Phenobarbital-induced embryos had an increased UDS response while TCB-induced embryos had a decreased UDS response, relative to noninduced embryos, for each dosage of AFB1. This suggests that the genotoxicity of an indirect-acting mutagen-carcinogen can be either increased or decreased, in vivo, depending on the inducer used. The chick embryo provides an excellent system for studying the effect of MFO induction on the genotoxicity of promutagen-carcinogens in a developing system. PMID:6420149

  4. Age-dependent basal level and induction capacity of copper-zinc and manganese superoxide dismutase and other scavenging enzyme activities in leukocytes from young and elderly adults.

    PubMed Central

    Niwa, Y.; Iizawa, O.; Ishimoto, K.; Akamatsu, H.; Kanoh, T.

    1993-01-01

    Several enzymes, including superoxide dismutase (SOD), catalase, glutathione peroxidase, and D-glucose-6-phosphate dehydrogenase are capable of scavenging reactive oxygen species in in vivo. We assessed both basal levels and the capacity of these enzyme activities to be induced in human leukocytes in response to a variety of agents. Basal activity of copper-zinc SOD, and manganese SOD showed little variation with age. In contrast, the basal activity of the three H2O2 scavenging enzymes, catalase, glutathione peroxidase, and D-glucose-6-phosphate dehydrogenase, was significantly higher in younger adults than in elderly individuals. Both manganese SOD and copper, zinc SOD activities were significantly induced by paraquat, interleukin-1, tumor necrosis factor, adriamycin, and bleomycin in lymphocytes and neutrophils from asymptomatic non-aged adults, whereas neither activity was induced in aged individuals. In contrast, glutathione peroxidase activity was significantly induced in both groups of subjects, whereas catalase and D-glucose-6-phosphate dehydrogenase were only slightly induced in either. Enzyme induction with paraquat, adriamycin, or bleomycin was inhibitable by neutralizing antibody to interleukin-1 and tumor necrosis factor, suggesting that the inductions observed with these three drugs are due to the distal mediators, interleukin-1 or tumor necrosis factor released from the cells. Finally, as observed in the regulation of genes in eukaryotes (Storz et al: Bacterial defenses against oxidative stress. Trends Genetics 1990, 6:363-368, ref. 1) O2- and H2O2 seem to differ in the rate of change with age in both basal levels and inducibility under oxygen stress. PMID:8317554

  5. Enzyme induction and histopathology elucidate aryl hydrocarbon receptor-mediated versus non-aryl hydrocarbon receptor-mediated effects of Aroclor 1268 in American mink (Neovison vison).

    PubMed

    Folland, William R; Newsted, John L; Fitzgerald, Scott D; Fuchsman, Phyllis C; Bradley, Patrick W; Kern, John; Kannan, Kurunthachalam; Zwiernik, Matthew J

    2016-03-01

    Polychlorinated biphenyl (PCB) concentrations reported in preferred prey and blubber of bottlenose dolphins from the Turtle-Brunswick River estuary (Georgia, USA) suggest the potential for adverse effects. However, PCBs in Turtle-Brunswick River estuary dolphins are primarily derived from Aroclor 1268, and predicting toxic effects of Aroclor 1268 is uncertain because of the mixture's unique composition and associated physiochemical characteristics. These differences suggest that toxicity benchmarks for other PCB mixtures may not be relevant to dolphins exposed to Aroclor 1268. American mink (Neovison vison) were used as a surrogate model for cetaceans to characterize mechanisms of action associated with Aroclor 1268 exposure. Mink share similarities in phylogeny and life history with cetaceans and are characteristically sensitive to PCBs, making them an attractive surrogate species for marine mammals in ecotoxicity studies. Adult female mink and a subsequent F1 generation were exposed to Aroclor 1268 through diet, and effects on enzyme induction, histopathology, thyroid hormone regulation, hematology, organ weights, and body condition index were compared to a negative control and a 3,3',4,4',5-pentachlorobiphenyl (PCB 126)-positive control. Aroclor 1268 dietary exposure concentrations ranged from 1.8 µg/g wet weight to 29 µg/g wet weight. Anemia, hypothyroidism, and hepatomegaly were observed in mink exposed to Aroclor 1268 beyond various dietary thresholds. Cytochrome P450 induction and squamous epithelial proliferation jaw lesions were low in Aroclor 1268 treatments relative to the positive control. Differences in enzyme induction and the development of squamous epithelial proliferation jaw lesions between Aroclor 1268 treatments and the positive control, coupled with effects observed in Aroclor 1268 treatments not observed in the positive control, indicate that mechanisms additional to the aryl hydrocarbon receptor-mediated pathway are associated with

  6. Increased tolerance to oxidative stress in transgenic tobacco expressing a wheat oxalate oxidase gene via induction of antioxidant enzymes is mediated by H2O2.

    PubMed

    Wan, Xiaoqing; Tan, Jiali; Lu, Shaoyun; Lin, Chuyu; Hu, Yihong; Guo, Zhenfei

    2009-05-01

    Hydrogen peroxide (H(2)O(2)) plays a key role in the regulation of plant responses to various environmental stresses and modulates the expression of related genes including those encoding antioxidant enzymes. A wheat oxalate oxidase (OxO) gene was transformed and expressed in tobacco for production of H(2)O(2). The transgenic plants exhibited enhanced OxO activities and H(2)O(2) concentrations, which was blocked by inhibitors of OxO. The transgenic plants showed increased tolerance to methyl viologen (MV) or high light-induced oxidative stress in both short-time and long-time tests by measuring their maximal photochemical efficiency of PSII (F(v)/F(m)), ion leakage and malondialdehyde. Higher activities and transcripts of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) were observed in the transgenic plants compared to their wild-type controls under normal growth conditions. Pretreatments with inhibitors of OxO and scavenger of H(2)O(2) blocked the increase of tolerance to MV-induced or high light-induced oxidative stress, as well as the induction of antioxidant enzyme activities. Pretreatments with H(2)O(2) increased tolerance to oxidative stresses and antioxidant enzyme activities. It is suggested that H(2)O(2) produced by OxO in the transgenic tobacco plants triggers the signaling pathways to upregulate expressions of antioxidant enzyme genes, which in turn results in the increase of tolerance to MV-induced and high light-induced oxidative stresses. PMID:19508366

  7. Stress-related variation in antioxidative enzymes activity and cell metabolism efficiency associated with embryogenesis induction in isolated microspore culture of triticale (x Triticosecale Wittm.).

    PubMed

    Zur, Iwona; Dubas, Ewa; Golemiec, Elzbieta; Szechyńska-Hebda, Magdalena; Gołebiowska, Gabriela; Wedzony, Maria

    2009-08-01

    Isolated microspore cultures of two spring triticale (x Triticosecale Wittm.) cultivars were used to examine the effect of various stress treatments (either high--32 degrees C or low--5 degrees C temperature with or without nitrogen/carbohydrate starvation) applied to excised anthers on the effectiveness of microspore embryogenesis induction. To quantify the effects of pretreatment conditions, the activity of antioxidative enzymes (catalase, peroxidase and superoxide dismutase) together with respiration rate and heat emission were measured. It was observed that heat shock treatment applied as the only one stress factor increased the activity of antioxidative enzymes which suggests intensive generation of reactive oxygen species. Such pretreatment effectively triggered microspore reprogramming but drastically decreased microspore viability. After low temperature treatment, the activity of antioxidative enzymes was similar to the control subjected only with the stress originated from the transfer to in vitro culture conditions. This pretreatment decreased the number of microspores entering embryogenesis but sustained cell viability and this effect prevailed in the final estimation of microspore embryogenesis effectiveness. For both, low- and high-temperature treatments, interaction with starvation stress was beneficial increasing microspore viability (at 5 degrees C) or efficiency of embryogenesis induction (at 32 degrees C). The latter treatment significantly reduced cell metabolic activity. Physiological background of these effects seems to be different and some hypothetical explanations have been discussed. Received data indicate that in triticale, anther preculture conditions could generate oxidative stress and change the cell metabolic activity which could next be reflected in the cell viability and the efficiency of microspore embryogenesis. PMID:19551385

  8. Ontogeny of the chicken cytochrome P-450 enzyme system. Expression and development of responsiveness to phenobarbital induction.

    PubMed

    Lorr, N A; Bloom, S E

    1987-09-15

    The sensitivity of the developing embryo to toxins and drugs is highly dependent on the state of development of the cytochrome P-450 system. Previous work in this laboratory has demonstrated the genotoxicity of aflatoxin B1 (AFB1) to the chicken embryo at 3 days of incubation (DI) and induction of AFB1 genotoxicity by phenobarbital at 7 DI. In this study, the basal and 24-hr phenobarbital (PB) induced levels of aminopyrine-N-demethylase (AMPD) and cytochrome P-450 were assayed in hepatic microsomes from 7 DI to 36 days posthatching (PH) and in microsomes from whole embryos at 5 DI. A dose-response for induction by PB was observed in embryonic hepatic microsomes as early as 7 DI, whereas a low level of cytochrome P-450 was detected in control 7 DI microsomes using the reduced CO vs oxidized CO difference spectrum. Basal levels of AMPD and cytochrome P-450 in hepatic microsomes increased steadily throughout development as did the responsiveness of the embryonic liver to induction with PB. Hepatic microsomes from control and PB-induced chickens had the highest AMPD activities posthatching particularly from 1 to 3 days PH. Maximal induced levels, which were 2- to 3-fold over control throughout development, ranged from 1.22 at 7 DI to 12.72 nmol HCHO/mg protein/min at 2 days PH. The potency of PB as an inducer increased about 1000-fold between 7 DI and hatching. PB induction did not increase the specific activity of AMPD at any period of development. The specific activity of AMPD posthatching increased about 3-fold above embryonic levels, indicating the development of a cytochrome P-450 complex more active toward aminopyrine in the neonatal period. PMID:3632724

  9. Induction of Heat Shock Proteins and Antioxidant Enzymes in 2,3,7,8-TCDD-Induced Hepatotoxicity in Rats

    PubMed Central

    Kim, Hyun-Sook; Park, So-Young; Yoo, Ki-Yeol

    2012-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is an environmental toxicant with a polyhalogenated aromatic hydrocarbon structure and is one of the most toxic man-made chemicals. Exposure to 2,3,7,8-TCDD induces reproductive toxicity, immunotoxicity, and hepatotoxicity. In this study, we evaluated how 2,3,7,8-TCDD-induced hepatotoxicity affect the expression of heat shock proteins and antioxidant enzymes using the real-time polymerase chain reaction (PCR) in rat. 2,3,7,8-TCDD increased heat shock protein (Hsp27, α-B-crystallin, Mortalin, Hsp105, and Hsp90s) and antioxidant enzymes (SOD-3, GST and catalase) expression after a 1 day exposure in livers of rats, whereas heat shock protein (α-B-crystallin, Hsp90, and GRP78) and antioxidant enzymes (SOD-1, SOD-3, catalase, GST, and GPXs) expression decreased on day 2 and then slowly recovered back to control levels on day 8. These results suggest that heat shock proteins and antioxidant enzymes were induced as protective mechanisms against 2,3,7,8-TCDD induced hepatotoxicity, and that prolonged exposure depressed their levels, which recovered to control levels due to reduced 2,3,7,8-TCDD induced hepatotoxicity. PMID:23269910

  10. Copper and zinc induction of lipid peroxidation and effects on antioxidant enzyme activities in the microalga Pavlova viridis (Prymnesiophyceae).

    PubMed

    Li, Mei; Hu, Changwei; Zhu, Qin; Chen, Li; Kong, Zhiming; Liu, Zhili

    2006-01-01

    The metal-induced lipid peroxidation and response of antioxidative enzymes have been investigated in the marine microalga Pavlova viridis to understand the mechanisms of metal resistance in algal cells. We have analyzed superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) activities and glutathione (GSH) contents in microalgal cells grown at different concentrations of copper and zinc. In response to each metal, lipid peroxidation was enhanced with the increase of concentrations, as an indication of the oxidative damage caused by metal concentration assayed in the microalgae cells. Exposure of P. viridis to the two metals caused changes in enzyme activities in a different manner, depending on the metal assayed: after copper treatments, total SOD activity was enhanced, while it was reduced after zinc exposure. Copper and zinc stimulated the activities of CAT and GSH whereas GPX showed a remarkable increase in activity in response to copper treatments and decrease after zinc treatments. These results suggest that an activation of some antioxidant enzymes was enhanced to counteract the oxidative stress induced by the two metals. PMID:16085277

  11. Inactivation of yeast Isw2 chromatin remodeling enzyme mimics longevity effect of calorie restriction via induction of genotoxic stress response

    PubMed Central

    Dang, Weiwei; Sutphin, George L.; Dorsey, Jean A.; Otte, Gabriel L.; Cao, Kajia; Perry, Rocco M.; Wanat, Jennifer J.; Saviolaki, Dimitra; Murakami, Christopher J.; Tsuchiyama, Scott; Robison, Brett; Gregory, Brian D.; Vermeulen, Michiel; Shiekhattar, Ramin; Johnson, F. Brad; Kennedy, Brian K.; Kaeberlein, Matt; Berger, Shelley L.

    2014-01-01

    Summary ATP-dependent chromatin remodeling is involved in all DNA transactions and linked to numerous human diseases. We explored functions of chromatin remodelers during cellular aging. Deletion of ISW2, or mutations inactivating the Isw2 enzyme complex, extends yeast replicative lifespan. This extension by ISW2 deletion is epistatic to the longevity effect of calorie restriction (CR) and this mechanism is distinct from suppression of TOR signaling by CR. Transcriptome analysis indicates that isw2Δ partially mimics an up-regulated stress response in CR cells. In particular, isw2Δ cells show an increased response to genotoxic stresses, and the DNA repair enzyme Rad51 is important for isw2Δ-mediated longevity. We show that lifespan is also extended in C. elegans by reducing levels of athp-2, a putative ortholog of Itc1/ACF1, a critical subunit of the enzyme complex. Our findings demonstrate that the ISWI class of ATP-dependent chromatin remodeling complexes play a conserved role during aging and in calorie restriction. PMID:24814484

  12. Proliferation of smooth endoplasmic reticulum and induction of microsomal drug-metabolizing enzymes after ether or halothane.

    PubMed

    Ross, W T; Cardell, R R

    1978-05-01

    Hepatic drug-metabolizing enzymes and hepatic ultrastructure were studied in rats after two hours of anesthesia with 1 MAC halothane or diethyl ether. Twelve hours after cessation of either anesthetic smooth endoplasmic reticulum was increased in centrilobular but not in periportal hepatocytes. This change persisted at 24- and 36-hour sampling times. Microsomal cytochrome P450 and cytochrome b5 decreased after halothane anesthesia (by 7 to 20 per cent of control). Diethyl ether caused increased cytochrome P450 and cytochrome b5 (27 and 18 per cent, respectively) at the 36-hour sampling time. NADPH cytochrome c reductase did not change significantly after either agent. The authors interpret these results to mean that both agents promote conversion of rough endoplasmic reticulum to smooth endoplasmic reticulum or, alternatively, that the anesthetics decrease degradation of smooth endoplasmic membranes. Since only ether caused an increase in the microsomal content of enzymes of the drug-metabolizing enzyme system, it is concluded that these two anesthetics act on hepatic cells by dissimilar mechanisms. PMID:646150

  13. Effects of benzyl isothiocyanate and its N-acetylcysteine conjugate on induction of detoxification enzymes in hepa1c1c7 mouse hepatoma cells.

    PubMed

    Hwang, Eun-Sun

    2014-12-01

    The induction of detoxification enzymes by benzyl isothiocyanate (BITC) and its synthetic N-acetyl-L-cysteine (NAC) conjugate (NAC-BITC) was examined in Hepa1c1c7 murine hepatoma cells. BITC and NAC-BITC inhibited Hepa1c1c7 cell growth in a dose-dependent manner. Cell growth was 4.5~57.2% lower in Hepa1c1c7 cells treated with 0.1~10 μM BITC than in control-treated Hepa1c1c7 cells. The NAC-BITC treatment had a similar inhibitory pattern on Hepa1c1c7 cell growth; 0.5 μM and 10 μM NAC-BITC decreased cell growth by 13.6% and 47.4%, respectively. Treatment of Hepa1c1c7 cells with 0.1~2.0 μM BITC also elicited a dose-response effect on the induction of quinone reductase quinone reductase (QR) activity and QR mRNA expression. Treatment with 1 μM and 2 μM BITC caused 1.8- and 2.8-fold inductions of QR mRNA, respectively. By comparison, treatment with 1 μM and 2 μM NAC-BITC caused 1.6- and 1.9-fold inductions of QR mRNA, respectively. Cytochrome P450 (CYP) 1A1 and CYP2E1 induction were lower in 0.1~2 μM BITC-treated cells than in control-treated cells. CYP2E1 activity was 1.2-fold greater in 0.1 μM NAC-BITC-treated cells than in control-treated cells. However, the CYP2E1 activity of cells treated with higher concentrations (i.e., 1~2 μM) of NAC-BITC was similar to the activity of control-treated cells. Considering the potential of isothiocyanatesto prevent cancer, these results provide support for the use of BITC and NAC-BITC conjugates as chemopreventive agents. PMID:25580390

  14. Effects of Benzyl Isothiocyanate and Its N-Acetylcysteine Conjugate on Induction of Detoxification Enzymes in Hepa1c1c7 Mouse Hepatoma Cells

    PubMed Central

    Hwang, Eun-Sun

    2014-01-01

    The induction of detoxification enzymes by benzyl isothiocyanate (BITC) and its synthetic N-acetyl-L-cysteine (NAC) conjugate (NAC-BITC) was examined in Hepa1c1c7 murine hepatoma cells. BITC and NAC-BITC inhibited Hepa1c1c7 cell growth in a dose-dependent manner. Cell growth was 4.5~57.2% lower in Hepa1c1c7 cells treated with 0.1~10 μM BITC than in control-treated Hepa1c1c7 cells. The NAC-BITC treatment had a similar inhibitory pattern on Hepa1c1c7 cell growth; 0.5 μM and 10 μM NAC-BITC decreased cell growth by 13.6% and 47.4%, respectively. Treatment of Hepa1c1c7 cells with 0.1~2.0 μM BITC also elicited a dose-response effect on the induction of quinone reductase quinone reductase (QR) activity and QR mRNA expression. Treatment with 1 μM and 2 μM BITC caused 1.8- and 2.8-fold inductions of QR mRNA, respectively. By comparison, treatment with 1 μM and 2 μM NAC-BITC caused 1.6- and 1.9-fold inductions of QR mRNA, respectively. Cytochrome P450 (CYP) 1A1 and CYP2E1 induction were lower in 0.1~2 μM BITC-treated cells than in control-treated cells. CYP2E1 activity was 1.2-fold greater in 0.1 μM NAC-BITC-treated cells than in control-treated cells. However, the CYP2E1 activity of cells treated with higher concentrations (i.e., 1~2 μM) of NAC-BITC was similar to the activity of control-treated cells. Considering the potential of isothiocyanatesto prevent cancer, these results provide support for the use of BITC and NAC-BITC conjugates as chemopreventive agents. PMID:25580390

  15. Induction of Defense-Related Enzymes in Banana Plants: Effect of Live and Dead Pathogenic Strain of Fusarium oxysporum f. sp. cubense

    PubMed Central

    Thakker, Janki N.; Patel, Samiksha; Dhandhukia, Pinakin C.

    2013-01-01

    The aim of the present study was to scrutinize the response of banana (Grand Naine variety) plants when interacting with dead or live pathogen, Fusarium oxysporum f.sp. cubense, a causative agent of Panama disease. Response of plants was evaluated in terms of induction of defense-related marker enzyme activity, namely, peroxidase (POX), polyphenol oxidase (PPO), β-1,3 glucanase, chitinase, and phenolics. Plant's interaction with live pathogen resulted in early induction of defense to restrain penetration as well as antimicrobial productions. However, pathogen overcame the defense of plant and caused disease. Interaction with dead pathogen resulted in escalating defense response in plants. Later on plants inoculated with dead pathogen showed resistance to even forced inoculation of live pathogen. Results obtained in the present study suggest that dead pathogen was able to mount defense response in plants and provide resistance to Panama disease upon subsequent exposure. Therefore, preparation from dead pathogen could be a potential candidate as a biocontrol agent or plant vaccine to combat Panama disease. PMID:25969777

  16. Developmental Regulation and Induction of Cytochrome P450 2W1, an Enzyme Expressed in Colon Tumors

    PubMed Central

    Choong, Eva; Guo, Jia; Persson, Anna; Virding, Susanne; Johansson, Inger; Mkrtchian, Souren; Ingelman-Sundberg, Magnus

    2015-01-01

    Cytochrome P450 2W1 (CYP2W1) is expressed predominantly in colorectal and also in hepatic tumors, whereas the levels are insignificant in the corresponding normal human adult tissues. CYP2W1 has been proposed as an attractive target for colorectal cancer (CRC) therapy by exploiting its ability to activate duocarmycin prodrugs to cytotoxic metabolites. However, its endogenous function, regulation and developmental pattern of expression remain unexplored. Here we report the CYP2W1 developmental expression in the murine and human gastrointestinal tissues. The gene expression in the colon and small intestine commence at early stages of embryonic life and is completely silenced shortly after the birth. Immunohistochemical analysis of human fetal colon revealed that CYP2W1 expression is restricted to the crypt cells. The silencing of CYP2W1 after birth correlates with the increased methylation of CpG-rich regions in both murine and human CYP2W1 genes. Analysis of CYP2W1 expression in the colon adenocarcinoma cell line HCC2998 revealed that the gene expression can be induced by e.g. the antitumor agent imatinib, linoleic acid and its derivatives. The imatinib mediated induction of CYP2W1 suggests an adjuvant therapy to treatment with duocarmycins that thus would involve induction of tumor CYP2W1 levels followed by the CYP2W1 activated duocarmycin prodrugs. Taken together these data strongly support further exploration of CYP2W1 as a specific drug target in CRC. PMID:25844926

  17. Induction of energy metabolism related enzymes in yeast Saccharomyces cerevisiae exposed to ibogaine is adaptation to acute decrease in ATP energy pool.

    PubMed

    Paskulin, Roman; Jamnik, Polona; Obermajer, Natasa; Slavić, Marija; Strukelj, Borut

    2010-02-10

    Ibogaine has been extensively studied in the last decades in relation to its anti-addictive properties that have been repeatedly reported as being addiction interruptive and craving eliminative. In our previous study we have already demonstrated induction of energy related enzymes in rat brains treated with ibogaine at a dose of 20mg/kg i.p. 24 and 72 h prior to proteomic analysis. In this study a model organism yeast Saccharomyces cerevisiae was cultivated with ibogaine in a concentration of 1mg/l. Energy metabolism cluster enzymes glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, enolase and alcohol dehydrogenase were induced after 5h of exposure. This is a compensation of demonstrated ATP pool decrease after ibogaine. Yeast in a stationary growth phase is an accepted model for studies of housekeeping metabolism of eukaryotes, including humans. Study showed that ibogaine's influence on metabolism is neither species nor tissue specific. Effect is not mediated by binding of ibogaine to receptors, as previously described in literature since they are lacking in this model. PMID:19853595

  18. The acu-1 gene of Coprinus cinereus is a regulatory gene required for induction of acetate utilisation enzymes.

    PubMed

    Maconochie, M K; Connerton, I F; Casselton, L A

    1992-08-01

    We have isolated a gene from Coprinus cinereus which cross-hybridises to the facA and acu-5 genes of Aspergillus nidulans and Neurospora crassa, respectively. These genes encode acetyl-CoA synthetase, an enzyme which is inducible by acetate and required for growth on acetate as sole carbon source. We have designated the C. cinereus gene acs-1 and have used transformation to demonstrate its functional homology to the ascomycete genes by complementation of an N. crassa acu-5 mutation. The acs-1 gene has never been identified by mutation; mutations leading to loss of acetyl-CoA synthetase function map to another gene, acu-1. Using Northern analyses we have shown that acu-1 has a regulatory function that is required for acetate-induced transcription of acs-1 and of another acetate utilisation gene, acu-7, the isocitrate lyase structural gene. PMID:1354839

  19. Induction of drug-metabolizing enzymes by tricyclic antidepressants in human liver: characterization and partial resolution of cytochromes P-450.

    PubMed Central

    Cresteil, T; Célier, C; Kremers, P; Flinois, J P; Beaune, P; Leroux, J P

    1983-01-01

    Drug-metabolizing enzyme activities were determined in liver microsomes from six kidney-transplant donors, one tricyclic antidepressant-treated and five untreated donors. The tricyclic antidepressant treatment modifies neither the overall cytochrome P-450 content of the liver, nor enzymatic activities of 4-nitroanisole demethylase, aniline hydroxylase, epoxide hydrolase and glutathione S-transferase. Only benzphetamine and ketotifen demethylation and conjugation of bilirubin with UDP-glucuronic acid are markedly augmented (more than two-fold). Separation of the different cytochrome P-450 fractions on a DEAE cellulose column indicates a modification of the elution pattern: the fraction increased by tricyclic antidepressants is responsible for the enhanced monooxygenase activity towards benzopyrene and benzphetamine. PMID:6661349

  20. T-lymphocyte induction of human monocyte angiotensin converting enzyme (ACE) is not dependent upon T-lymphocyte proliferation

    SciTech Connect

    Vuk-Pavlovic, Z.; Rohrbach, M.S.

    1986-03-05

    Human peripheral blood monocytes cultured in serum free media for seven days show a basal activity of the ectoenzyme ACE which is augmented 2-3 times by the presence of autologous peripheral blood T-lymphocytes. Since these two cell types are also involved in autologous mixed lymphocyte reaction if serum is present, the authors compared the ability of T-cells to stimulate ACE activity in the presence or absence of proliferation (measured by /sup 3/H-thymidine incorporation). By the seventh day, cultures with 5% AB/sup +/ serum showed significant increase in proliferation but no increase in ACE activity compared to the serum free cultures. Even higher proliferation rate achieved by co-culturing T-lymphocytes with allogeneic monocytes did not increase ACE production; on the contrary, ACE activity remained at the basal level. Monocyte-T-cell co-cultures stimulated with increasing concentrations of ConA or PHA showed dose dependent increases in proliferation but parallel decreases in ACE activity. Addition of soluble antigen (Candida albicans) also enhanced proliferation but not ACE synthesis. They conclude that T-lymphocyte induction of monocyte ACE is a result of cooperation between autologous cells which is not dependent upon T-cell proliferation.

  1. Auto-induction-based rapid evaluation of extracellular enzyme expression from lac operator-involved recombinant Escherichia coli.

    PubMed

    Chen, Wen-Bo; Nie, Yao; Mu, Xiao-Qing; Yan, Wei; Xu, Yan; Xiao, Rong

    2014-12-01

    Degeneration of engineered strains and decreased production of target gene products were often observed during recombinant bioprocess. Although several strategies have been developed to ensure high levels of target gene products, these methods seemed to be complex and laborious. By investigating possible factors contributing to the decreased yield, degeneration of host cells was identified as the main cause. Based on the principle of auto-induction and the fact that the interaction between colored substrates and gene products could present visible changes, a convenient and accurate screening method was developed to evaluate the production performance of engineered strains. Due to the typicality of pullulanase from genus Klebsiella, which has been a model for the research of secretion mechanism in gram-negative bacteria, an engineered E. coli producing extracellular pullulanase was employed to illustrate the method. Consequently, according to the capability to form a colorless halo, colonies could be divided into two groups, one surrounded by clear zone and the other unable to present transparent haloes. Furthermore, the high capability of these colonies was confirmed by performing pullulanase production in liquid medium. Compared with other methods for evaluating engineered strains, the visible screening technique was suggested to have the advantages of effectiveness and accuracy. PMID:25234392

  2. Enzyme induction and acute endocrine effects in prepubertal female rats receiving environmental PCB/PCDF/PCDD mixtures.

    PubMed Central

    Li, M H; Hansen, L G

    1996-01-01

    Air, subsurface soil, and superficial dust from a National Priorities List landfill located in southern Illinois were sampled to determine their potential toxicities. The major components of these landfill extracts were polychlorinated biphenyls (PCBs), with significant amounts of polychlorinated dibenzofurans (PCDFs) and small amounts of polychlorinated dibenzodioxins (PCDDs). The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency factor approach has been proposed to estimate the toxic potency of complex mixtures of chlorinated aromatics for environmental risk assessment. However, most components of environmental residues are nonplanar and do not act as aryl hydrocarbon (Ah) receptor agonists, so there is a great risk of not identifying adverse responses that are not dioxinlike. We used a 2-day prepubertal female rat bioassay to examine multiple biological responses, including both dioxinlike and nondioxinlike effects from these landfill extracts. As expected, both types of effects were detected. The soil and dust extracts produced similar dose-response relationships for 7-ethoxyresorufin O-deethylase, 7-pentoxyresorufin O-depentylase, 7-benzyloxyresorufin O-debenzylase, and 4-nitrophenol UDP-glucuronyltransferase induction; the dose response for the air extract deviated from the other two extracts. Soil, dust, and air extracts effectively reduced serum total thyroxine (T4) with similar dose-response relationships, despite the significantly different TCDD toxic equivalent (TEQ) values of these three extracts. Both soil (346 mg PCB/kg) and air (175 mg PCB/kg) extracts caused a greater than 30% increase in uterine wet weight. This study suggests that a more comprehensive approach is required to improve current risk assessment of environmental mixtures. TCDD TEQs reflect only a portion of effects and may especially underpredict effects on T4. Images p712-a Figure 1. A Figure 1. B Figure 1. C Figure 2. A Figure 2. B Figure 3. A Figure 3. B Figure 4. A Figure

  3. Enzyme induction and acute endocrine effects in prepubertal female rats receiving environmental PCB/PCDF/PCDD mixtures.

    PubMed

    Li, M H; Hansen, L G

    1996-07-01

    Air, subsurface soil, and superficial dust from a National Priorities List landfill located in southern Illinois were sampled to determine their potential toxicities. The major components of these landfill extracts were polychlorinated biphenyls (PCBs), with significant amounts of polychlorinated dibenzofurans (PCDFs) and small amounts of polychlorinated dibenzodioxins (PCDDs). The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency factor approach has been proposed to estimate the toxic potency of complex mixtures of chlorinated aromatics for environmental risk assessment. However, most components of environmental residues are nonplanar and do not act as aryl hydrocarbon (Ah) receptor agonists, so there is a great risk of not identifying adverse responses that are not dioxinlike. We used a 2-day prepubertal female rat bioassay to examine multiple biological responses, including both dioxinlike and nondioxinlike effects from these landfill extracts. As expected, both types of effects were detected. The soil and dust extracts produced similar dose-response relationships for 7-ethoxyresorufin O-deethylase, 7-pentoxyresorufin O-depentylase, 7-benzyloxyresorufin O-debenzylase, and 4-nitrophenol UDP-glucuronyltransferase induction; the dose response for the air extract deviated from the other two extracts. Soil, dust, and air extracts effectively reduced serum total thyroxine (T4) with similar dose-response relationships, despite the significantly different TCDD toxic equivalent (TEQ) values of these three extracts. Both soil (346 mg PCB/kg) and air (175 mg PCB/kg) extracts caused a greater than 30% increase in uterine wet weight. This study suggests that a more comprehensive approach is required to improve current risk assessment of environmental mixtures. TCDD TEQs reflect only a portion of effects and may especially underpredict effects on T4. PMID:8841756

  4. Early genes induction in spontaneously hypertensive rats left ventricle with angiotensin-converting enzyme inhibitors but not hydralazine

    SciTech Connect

    Susic, D.; Aristizabal, D.J.; Prakash, O.; Nunez, E.; Frohlich, E.D.

    1995-12-01

    Spontaneously hypertensive rats were given an angiotensin-converting enzyme (ACE) inhibitor (benazepril or quinapril) or hydralazine and were left for up to 6 hr. To examine whether administration of antihypertensive agents affects expression of immediate early genes in left ventricular myocardium, groups of rats were sacrificed at 1, 3, and 6 hr after dosing; total RNA was extracted from left ventricular tissue and analyzed by blot hybridization technique using labeled probes for c-myc, c-fos, and GAPDH mRNA. All three antihypertensive agents reduced pressure similarly, and treatment with the two ACE inhibitors increased c-fos and c-myc mRNA expression in left ventriculum. By contrast, hydralazine did not increase steady-state mRNA expression of either proto-oncogene. Thus, in parallel with the pressure fall, acute administration of the ACE inhibitors induced expression of c-fos and c-myc mRNAs in the left ventricle. Since the equidepressor dose of hyralazine did not affect expression of these proto-oncogenes, this effect of ACE inhibitors is independent of their hemodynamic action. 27 refs., 1 fig., 2 tabs.

  5. cis-terpin hydrate metabolism by a Brevibacterium: patterns of enzyme induction, and accumulation of -terpineol in growth.

    PubMed

    Baum, R H; Marr, E K

    1972-04-01

    A brevibacterium, strain TH-4, previously isolated by aerobic enrichment on the monocyclic monoterpenoid cis-terpin hydrate as a sole carbon and energy source, was found to grow on alpha-terpineol and on a number of common sugars and organic acids. Oxidation of these terpenoids was shown to occur via an induced enzyme system, as measured manometrically by oxygen uptake and prevention of protein synthesis with chloramphenicol or puromycin. Oxidation of terpin hydrate by cell suspensions appeared to be coincidentally induced by growth on alpha-terpineol, and oxidation of alpha-terpineol similarly appeared to be induced by growth on terpin hydrate. Culture fluids in which the TH-4 organism was grown at the expense of cis-terpin hydrate were found to contain (-)-alpha-terpineol in combined butanol-ether extracts. The isolated compound was shown to be chromatographically and spectrophotometrically identical to an authentic sample of alpha-terpineol. The stereospecificity of an enzymatic dehydration of terpin hydrate to alpha-terpineol is considered. PMID:4336108

  6. The effect of fenbuconazole on cell proliferation and enzyme induction in the liver of female CD1 mice

    SciTech Connect

    Juberg, Daland R.; Mudra, Daniel R.; Hazelton, George A.; Parkinson, Andrew

    2006-07-15

    Fenbuconazole, a triazole fungicide, has been associated with an increase in the incidence of liver adenomas in female mice following long-term dietary exposure. The aim of this study was to evaluate whether the mode of action for liver tumor formation by fenbuconazole is similar to that of phenobarbital. Treatment of CD1 mice with 0, 20, 60, 180 or 1300 ppm fenbuconazole for up to 4 weeks caused a dose-dependent increase in liver weight that was associated with centrilobular hepatocellular hypertrophy, cytoplasmic eosinophilia and panlobular hepatocellular vacuolation, as well as an initial increase in the cell proliferation labeling index. Fenbuconazole also caused a dose-dependent increase in liver microsomal cytochromes b{sub 5} and P450 and the levels of immunoreactive CYP2B10 and its associated activity 7-pentoxyresorufin O-dealkylation (PROD). Treatment of mice with 1000 ppm phenobarbital elicited the same effects as treatment of mice with 1300 ppm fenbuconazole, except that phenobarbital was more effective than fenbuconazole at inducing PROD activity, even though fenbuconazole induced CYP2B10 to the same extent as did phenobarbital. This difference was attributed to the ability of fenbuconazole to bind tightly to CYP2B10 and partially mask its catalytic activity in liver microsomes, which is characteristic of several azole-containing drugs. All hepatocellular changes and induced enzyme activity returned to control levels within 4 weeks of discontinuing treatment with fenbuconazole or phenobarbital, indicating that the observed changes were fully reversible. We conclude that fenbuconazole is a phenobarbital-type inducer of mouse liver cytochrome P450, and the mode of action by which fenbuconazole induces liver adenomas in mice is similar to that of phenobarbital.

  7. N-vinylpyrrolidone dimer, a novel formulation excipient, causes hepatic and thyroid hypertrophy through the induction of hepatic microsomal enzymes in rats.

    PubMed

    Yang, Yi; Ciurlionis, Rita; Kowalkowski, Kenneth; Marsh, Kennan C; Bracken, William M; Blomme, Eric A G

    2012-01-01

    N-vinylpyrrolidone dimer (VPD) is a novel experimental formulation excipient intended for preclinical toxicology studies. In a previous 4-week toxicity study, VPD induced dose-dependent hepatocellular and thyroid gland hypertrophy in Sprague-Dawley (SD) rats. The objectives of the current investigation were to define the underlying molecular mechanisms of these changes. Two separate studies were conducted using male SD rats, daily doses of 300, 1000 or 3,000 mg/kg of VPD, and a positive control (phenobarbital at 75 mg/kg/day): (1) a 28-day study to monitor thyroid hormone levels after 7 and 28 days of dosing; (2) a 5-day study to evaluate hepatic and thyroid gland transcriptomic changes, as well as hepatic UGT activity levels. At VPD dosages of 300 mg/kg/day and higher, 2-fold increases of serum thyroid stimulating hormone (TSH) levels were observed in male SD rats after 28 days of dosing, while serum thyroxine (T4) and triiodothyronine (T3) levels were unchanged. Liver UGT enzyme activity levels were increased in VPD-treated rats after 5 days. In addition, in the 5-day study, VPD caused increased hepatic mRNA levels of a panel of drug metabolizing enzymes (DMEs) and transporters, including Cyp3a1, Cyp2b1, Ugt 2b1, and Abcc3. Similar patterns of induction were observed in primary rat hepatocytes exposed to VPD. Transcriptomic changes in the thyroid gland were identified for genes involved in thyroid hormone biosynthesis and in the FAK, PTEN, and Wnt/β-catenin signaling pathways. Collectively, these data indicate that VPD acts as an inducer of hepatic DMEs in SD rats and that this likely leads to enhanced peripheral metabolism of T3/T4, resulting in a feedback response characterized by increased serum TSH levels, and thyroid gland hypertrophy and hyperplasia. PMID:22037397

  8. TLR2 dependent induction of vitamin A metabolizing enzymes in dendritic cells promotes T regulatory responses and inhibits TH-17 mediated autoimmunity

    PubMed Central

    Manicassamy, Santhakumar; Ravindran, Rajesh; Deng, Jiusheng; Oluoch, Herold; Denning, Timothy L; Kasturi, Sudhir Pai; Rosenthal, Kristen M.; Evavold, Brian D.; Pulendran, Bali

    2009-01-01

    Immune sensing of a microbe occurs via multiple receptors. How signals from different receptors are coordinated to yield a specific immune response is poorly understood. We demonstrate that the different pathogen recognition receptors, TLR2 and dectin-1, recognizing the same microbial stimulus, stimulate distinct innate and adaptive responses. TLR2 signaling induced splenic dendritic cells (DCs) to express the retinoic acid (RA) metabolizing enzyme Raldh2 and IL-10, and to metabolize vitamin A and stimulate Foxp3+ T regulatory cells (Treg cells). RA acted on DCs to induce Socs3 expression, which suppressed activation of p38 MAPK and pro-inflammatory cytokines. Consistent with this, TLR2 signaling induced Treg cells, and suppressed IL-23 and TH-17/ TH-1 mediated autoimmune responses in vivo. In contrast, dectin-1 signaling mostly induced IL-23 and pro-inflammatory cytokines, and augmented TH-17/ TH-1 mediated autoimmune responses in vivo. These data define a new mechanism for the systemic induction of RA and immune suppression against autoimmunity. PMID:19252500

  9. Toll-like receptor 2-dependent induction of vitamin A-metabolizing enzymes in dendritic cells promotes T regulatory responses and inhibits autoimmunity.

    PubMed

    Manicassamy, Santhakumar; Ravindran, Rajesh; Deng, Jiusheng; Oluoch, Herold; Denning, Timothy L; Kasturi, Sudhir Pai; Rosenthal, Kristen M; Evavold, Brian D; Pulendran, Bali

    2009-04-01

    Immune sensing of a microbe occurs via multiple receptors. How signals from different receptors are coordinated to yield a specific immune response is poorly understood. We show that two pathogen recognition receptors, Toll-like receptor 2 (TLR2) and dectin-1, recognizing the same microbial stimulus, stimulate distinct innate and adaptive responses. TLR2 signaling induced splenic dendritic cells (DCs) to express the retinoic acid metabolizing enzyme retinaldehyde dehydrogenase type 2 and interleukin-10 (IL-10) and to metabolize vitamin A and stimulate Foxp3(+) T regulatory cells (T(reg) cells). Retinoic acid acted on DCs to induce suppressor of cytokine signaling-3 expression, which suppressed activation of p38 mitogen-activated protein kinase and proinflammatory cytokines. Consistent with this finding, TLR2 signaling induced T(reg) cells and suppressed IL-23 and T helper type 17 (T(H)17) and T(H)1-mediated autoimmune responses in vivo. In contrast, dectin-1 signaling mostly induced IL-23 and proinflammatory cytokines and augmented T(H)17 and T(H)1-mediated autoimmune responses in vivo. These data define a new mechanism for the systemic induction of retinoic acid and immune suppression against autoimmunity. PMID:19252500

  10. In vitro inhibition and induction of human liver cytochrome P450 enzymes by gentiopicroside: potent effect on CYP2A6.

    PubMed

    Deng, Yating; Wang, Lu; Yang, Yong; Sun, Wenji; Xie, Renming; Liu, Xueying; Wang, Qingwei

    2013-01-01

    Gentiopicroside (GE), a naturally occurring iridoid glycoside, has been developed into a Novel Traditional Chinese Drug named gentiopicroside injection, and it was approved for the treatment of acute jaundice and chronic active hepatitis by SFDA. However, the inhibitory and inducible effects of GE on the activity of cytochrome P450 (CYP450) are unclear. The purpose of this study was to evaluate the ability of GE to inhibit and induce human cytochrome P450 enzymes in vitro. In human liver microsomes, GE inhibited CYP2A6 and CYP2E1 in a concentration-dependent manner, with IC₅₀ values of 21.8 µg/ml and 594 µg/ml, respectively, and the IC₅₀ of CYP2A6 was close to the C(max) value observed clinically. GE was a non-competitive inhibitor of CYP2A6 at lower concentrations and a competitive inhibitor at higher concentrations. GE did not produce inhibition of CYP2C9, CYP2D6, CYP1A2 or CYP3A4 activities. However, a significant increase of CYP1A2 and CYP3A4 activity was observed at high concentrations. In cultured human hepatocytes no significant induction of CYP1A2, CYP3A4 or CYP2B6 was observed. Given these results, the in vivo potential inhibition of GE on CYP2A6 deserves further investigation, and it seems that the hepatoprotective effect of GE is irrelevant to its effect on P450s. PMID:23419353

  11. Mutual augmentation of the induction of the histamine-forming enzyme, histidine decarboxylase, between alendronate and immuno-stimulants (IL-1, TNF, and LPS), and its prevention by clodronate

    SciTech Connect

    Deng Xue; Yu Zhiqian; Funayama, Hiromi; Shoji, Noriaki; Sasano, Takashi; Iwakura, Yoichiro; Sugawara, Shunji; Endo, Yasuo . E-mail: endo@pharmac.dent.tohoku.ac.jp

    2006-05-15

    Nitrogen-containing bisphosphonates (N-BPs), powerful anti-bone-resorptive drugs, have inflammatory side effects, while histamine is not only an inflammatory mediator, but also an immuno-modifier. In murine models, a single intraperitoneal injection of an N-BP induces various inflammatory reactions, including the induction of the histamine-forming enzyme histidine decarboxylase (HDC) in tissues important in immune responses (such as liver, lungs, spleen, and bone marrow). Lipopolysaccharide (LPS) and the proinflammatory cytokines IL-1 and TNF are also capable of inducing HDC. We reported previously that in mice (i) the inflammatory actions of N-BPs depend on IL-1 (ii) N-BP pretreatment augments both LPS-stimulated IL-1 production and HDC induction, and (iii) the co-administration of clodronate (a non-N-BP) with an N-BP inhibits the latter's inflammatory actions (including HDC induction). Here, we add the new findings that (a) pretreatment with alendronate (a typical N-BP) augments both IL-1- and TNF-induced HDC elevations, (b) LPS pretreatment augments the alendronate-induced HDC elevation, (c) co-administration of clodronate with alendronate abolishes these augmentations, (d) alendronate does not induce HDC in IL-1-deficient mice even if they are pretreated with LPS, and (e) alendronate increases IL-1{beta} in all tissues tested, but not in the serum. These results suggest that (1) there are mutual augmentations between alendronate and immuno-stimulants (IL-1, TNF, and LPS) in HDC induction, (2) tissue IL-1{beta} is important in alendronate-stimulated HDC induction, and (3) combination use of clodronate may have the potential to reduce the inflammatory effects of alendronate (we previously found that clodronate, conveniently, does not inhibit the anti-bone-resorptive activity of alendronate)

  12. Chemopreventive effects of diverse dietary phytochemicals against DMBA-induced hamster buccal pouch carcinogenesis via the induction of Nrf2-mediated cytoprotective antioxidant, detoxification, and DNA repair enzymes.

    PubMed

    Kavitha, K; Thiyagarajan, P; Rathna Nandhini, J; Mishra, Rajakishore; Nagini, S

    2013-08-01

    Identifying agents that activate nuclear factor erythroid-2 related factor-2 (Nrf2), a key regulator of various cytoprotective antioxidant, and detoxifying enzymes has evolved as a promising strategy for cancer chemoprevention. In the present study, we investigated the effect of dietary supplementation of structurally diverse phytochemicals- astaxanthin, blueberry, chlorophyllin, ellagic acid, and theaphenon-E on Nrf2 signaling, and xenobiotic-metabolizing and antioxidant enzymes in the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis model. We observed that these phytochemicals induce nuclear accumulation of Nrf2 while downregulating its negative regulator, Keap-1. This was associated with reduced expression of CYP1A1 and CYP1B1, the cytochrome P450 isoforms involved in the activation of DMBA, and the oxidative stress marker 8-hydroxy-2'-deoxyguanosine coupled with upregulation of the phase II detoxification enzymes glutathione S-transferases and NAD(P)H:quinone oxidoreductase 1 and the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase. In addition, these dietary phytochemicals also enhanced the DNA repair enzymes 8-oxoguanine glycosylase 1 (OGG1), xeroderma pigmentosum D (XPD), xeroderma pigmentosum G (XPG), and x-ray repair cross complementing group 1 (XRCC1). Our data provide substantial evidence that the dietary phytochemicals inhibit the development of HBP carcinomas through the activation of Nrf2/Keap-1 signaling and by upregulating cytoprotective enzymes. The extent of the chemopreventive effects of the phytochemicals was in the order: chlorophyllin > blueberry > ellagic acid > astaxanthin > theaphenon-E. Thus these dietary phytochemicals that function as potent activators of Nrf2 and its orchestrated response are novel candidates for cancer chemoprevention. PMID:23707664

  13. D-arabinose metabolism in Escherichia coli B: induction and cotransductional mapping of the L-fucose-D-arabinose pathway enzymes.

    PubMed

    Elsinghorst, E A; Mortlock, R P

    1988-12-01

    D-Arabinose is degraded by Escherichia coli B via some of the L-fucose pathway enzymes and a D-ribulokinase which is distinct from the L-fuculokinase of the L-fucose pathway. We found that L-fucose and D-arabinose acted as the apparent inducers of the enzymes needed for their degradation. These enzymes, including D-ribulokinase, appeared to be coordinately regulated, and mutants which constitutively synthesized the L-fucose enzymes also constitutively synthesized D-ribulokinase. In contrast to D-arabinose-positive mutants of E. coli K-12, in which L-fuculose-1-phosphate and D-ribulose-1-phosphate act as inducers of the L-fucose pathway, we found that these intermediates did not act as inducers in E. coli B. To further characterize the E. coli B system, some of the L-fucose-D-arabinose genes were mapped by using bacteriophage P1 transduction. A transposon Tn10 insertion near the E. coli B L-fucose regulon was used in two- and three-factor reciprocal crosses. The gene encoding D-ribulokinase, designated darK, was found to map within the L-fucose regulon, and the partial gene order was found to be Tn10-fucA-darK-fucI-fucK-thyA. PMID:3056899

  14. Induction of cancer chemopreventive enzymes by coffee is mediated by transcription factor Nrf2. Evidence that the coffee-specific diterpenes cafestol and kahweol confer protection against acrolein

    SciTech Connect

    Higgins, Larry G. Cavin, Christophe; Itoh, Ken; Yamamoto, Masayuki; Hayes, John D.

    2008-02-01

    Mice fed diets containing 3% or 6% coffee for 5 days had increased levels of mRNA for NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferase class Alpha 1 (GSTA1) of between 4- and 20-fold in the liver and small intestine. Mice fed 6% coffee also had increased amounts of mRNA for UDP-glucuronosyl transferase 1A6 (UGT1A6) and the glutamate cysteine ligase catalytic (GCLC) subunit of between 3- and 10-fold in the small intestine. Up-regulation of these mRNAs was significantly greater in mice possessing Nrf2 (NF-E2 p45 subunit-related factor 2) than those lacking the transcription factor. Basal levels of mRNAs for NQO1, GSTA1, UGT1A6 and GCLC were lower in tissues from nrf2{sup -/-} mice than from nrf2{sup +/+} mice, but modest induction occurred in the mutant animals. Treatment of mouse embryonic fibroblasts (MEFs) from nrf2{sup +/+} mice with either coffee or the coffee-specific diterpenes cafestol and kahweol (C + K) increased NQO1 mRNA up to 9-fold. MEFs from nrf2{sup -/-} mice expressed less NQO1 mRNA than did wild-type MEFs, but NQO1 was induced modestly by coffee or C + K in the mutant fibroblasts. Transfection of MEFs with nqo1-luciferase reporter constructs showed that induction by C + K was mediated primarily by Nrf2 and required the presence of an antioxidant response element in the 5'-upstream region of the gene. Luciferase reporter activity did not increase following treatment of MEFs with 100 {mu}mol/l furan, suggesting that this ring structure within C + K is insufficient for gene induction. Priming of nrf2{sup +/+} MEFs, but not nrf2{sup -/-} MEFs, with C + K conferred 2-fold resistance towards acrolein.

  15. Antioxidant Activity and Induction of mRNA Expressions of Antioxidant Enzymes in HEK-293 Cells of Moringa oleifera Leaf Extract.

    PubMed

    Vongsak, Boonyadist; Mangmool, Supachoke; Gritsanapan, Wandee

    2015-08-01

    The leaves of Moringa oleifera, collected in different provinces in Thailand, were determined for the contents of total phenolics, total flavonoids, major components, and antioxidant activity. The extract and its major active components were investigated for the inhibition of H2O2-induced reactive oxygen species production and the effects on antioxidant enzymes mRNA expression. The extract, crypto-chlorogenic acid, isoquercetin and astragalin, significantly reduced the reactive oxygen species production inducing by H2O2 in HEK-293 cells. Treatment with isoquercetin significantly increased the mRNA expression levels of antioxidant enzymes such as superoxide dismutase, catalase and heme oxygenase 1. These results confirm that M. oleifera leaves are good sources of natural antioxidant with isoquercetin as an active compound. PMID:26166137

  16. Studies on the alterations in haematological indices, micronuclei induction and pathological marker enzyme activities in Channa punctatus (spotted snakehead) perciformes, channidae exposed to thermal power plant effluent.

    PubMed

    Javed, Mehjbeen; Ahmad, Irshad; Ahmad, Ajaz; Usmani, Nazura; Ahmad, Masood

    2016-01-01

    The present study was conducted to assess the toxicity of thermal power plant effluent containing heavy metals (Fe > Cu > Zn > Mn > Ni > Co > Cr) on haematological indices, micronuclei, lobed nuclei and activity of pathological marker enzymes [alkaline phosphatase (ALP), aspartate transferase (AST), alanine transferase (ALT) and creatine kinase (CK)] in Channa punctatus. Total erythrocyte count (-54.52 %), hemoglobin (-36.98 %), packed cell volume (-36.25 %), mean corpuscular hemoglobin concentration (-1.41 %) and oxygen (O2) carrying capacity (-37.04 %) declined significantly over reference fish, however total leukocyte count (+25.43 %), mean corpuscular hemoglobin (+33.52 %) and mean corpuscular volume (+35.49 %) showed elevation. High frequency of micronuclei (1133.3 %) and lobed nuclei (150 %) were observed in exposed fish which may indicate mutagenesis. Activities of pathological marker enzymes ALP, AST, ALT and CK increased significantly in serum of exposed fish. The ratio of ALT: AST in exposed fish was beyond 1 which indicates manifestation of pathological processes. These biomarkers show that fish have macrocytic hypochromic anemia. Leukocytosis showed general defence response against heavy metal toxicity and marker enzymes showed tissue degeneration. In conclusion, thermal power plant effluent has strong potential to induce micronuclei, tissue pathology, making the fish anemic, weak, stressed and vulnerable to diseases. PMID:27386247

  17. Enzyme induction in rat lung and liver by condensates and fractions from main-stream and side-stream cigarette smoke

    SciTech Connect

    Pasquini, R.; Sforzolini, G.S.; Savino, A.; Angeli, G.; Monarca, S.

    1987-12-01

    Aryl hydrocarbon hydroxylase (AHH) and dimethylnitrosamine demethylase (DMND) activities in pulmonary and hepatic tissues of male Sprague-Dawley rats were assayed following pretreatment with known inducers (benzo(a)pyrene, 3-methylcholanthrene, Aroclor 1254, phenobarbital) and with main-stream (MS) and side-stream (SS) cigarette smoke condensates and their related fractions. Biochemical assays by spectrophotofluorimetry (AHH activity) and spetrophotometry (DMND activity) and by a biological assay (Ames test) were performed to detect AHH and DMND induction. Ames test proved to be much less sensitive than the spectrophotofluorimetric analysis for AHH determination. Both main-stream and side-stream cigarette smoke condensates and some fractions, containing water-soluble bases, water-insoluble bases, and polycyclic aromatic hydrocarbons, were found to induce AHH activity in lung and liver, the lung being induced to the greatest extent. The highest levels of AHH inducibility were found for the SS-smoke condensate and related fractions. In particular, the insoluble bases fractions gave the highest induction. On the contrary, pulmonary DMND activity was not affected by pretreatment with the same materials, while hepatic DMND response was only minimally induced by Aroclor and phenobarbital treatment.

  18. Carnosic acid protects against 6-hydroxydopamine-induced neurotoxicity in in vivo and in vitro model of Parkinson's disease: involvement of antioxidative enzymes induction.

    PubMed

    Wu, Chi-Rei; Tsai, Chia-Wen; Chang, Shu-Wei; Lin, Chia-Yuan; Huang, Li-Chun; Tsai, Chia-Wen

    2015-01-01

    The neuroprotective effects of carnosic acid (CA), a phenolic diterpene isolated from rosemary (Rosmarinus officinalis), have been widely investigated in recent years, however, its protection in in vivo still unclear. In this study, we investigated the behavioral activity and neuroprotective effects of CA in a rat model of Parkinson's disease (PD) induced by 6-hydroxydopamine (6-OHDA). Rats were treated with 20mg/kg body weight of CA for 3 weeks before 6-OHDA exposure. Results indicated that CA improved the locomotor activity and reduced the apomorphine-caused rotation in 6-OHDA-stimulated rats. Significant protection against lipid peroxidation and GSH reduction was observed in the 6-OHDA rats pretreated with CA. Pretreatment with CA increased the protein expression of γ-glutamate-cysteine ligase catalytic subunit, γ-glutamate-cysteine ligase modifier subunit, superoxide dismutase, and glutathione reductase compared with 6-OHDA-stimulated rats and SH-SY5Y cells. Immunoblots showed that the reduction of the Bcl-2/Bax ratio, the induction of caspase 3 cleavage, and the induction of poly(ADP-ribose) polymerase (PARP) cleavage by 6-OHDA was reversed in the presence of SB203580 (a p38 inhibitor) or SP600125 (a JNK inhibitor) in SH-SY5Y cells. Rats treated with CA reversed the 6-OHDA-mediated the activation of c-Jun NH2-terminal kinase and p38, the down-regulation of the Bcl-2/Bax ratio, the up-regulation of cleaved caspase 3/caspase 3 and cleaved PARP/PARP ratio, and the down-regulation of tyrosine hydroxylase protein. However, BAM7, an activator of Bax, attenuated the effect of CA on apoptosis in SH-SY5Y cells. These results suggest that CA protected against 6-OHDA-induced neurotoxicity is attributable to its anti-apoptotic and anti-oxidative action. The present findings may help to clarify the possible mechanisms of rosemary in the neuroprotection of PD. PMID:25446857

  19. Induction of resistance to alkylating agents in E. coli: the ada+ gene product serves both as a regulatory protein and as an enzyme for repair of mutagenic damage.

    PubMed Central

    Teo, I; Sedgwick, B; Demple, B; Li, B; Lindahl, T

    1984-01-01

    The expression of several inducible enzymes for repair of alkylated DNA in Escherichia coli is controlled by the ada+ gene. This regulatory gene has been cloned into a multicopy plasmid and shown to code for a 37-kd protein. Antibodies raised against homogeneous O6-methylguanine-DNA methyltransferase (the main repair activity for mutagenic damage in alkylated DNA) were found to cross-react with this 37-kd protein. Cell extracts from several independently derived ada mutants contain variable amounts of an altered 37-kd protein after an inducing alkylation treatment. In addition, an 18-kd protein identical with the previously isolated O6-methyl-guanine-DNA methyltransferase has been identified as a product of the ada+ gene. The smaller polypeptide is derived from the 37-kd protein by proteolytic processing. Images Fig. 1. Fig. 2. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. PMID:6092060

  20. Labor Induction

    MedlinePlus

    ... QUESTIONS FAQ154 LABOR, DELIVERY, AND POSTPARTUM CARE Labor Induction • What is labor induction? • Why is labor induced? • What is the Bishop ... oxytocin? • What are the risks associated with labor induction? • Is labor induction always effective? • Glossary What is ...

  1. Bioaccumulation and MFO enzyme induction of di, tri- and tetrachlorodibenzofurans and 2,3,7,8-TCDD in juvenile rainbow trout

    SciTech Connect

    Muir, D.; Yarechewski, A.; Metner, D.; Lockhart, L.

    1994-12-31

    Juvenile rainbow trout (3--10 g) were exposed to dietary 2,8-di-, 2,3,8-tri-, and 2,3,7,8-tetrachlorodibenzofuran (TCDF) and to 2,3,7,8-TCDD in separate experiments. Elimination was studied for up to 180 days following a 30 days exposure. The authors compared the MFO induction potency, assimilation efficiencies, biomagnification factors and elimination rates of di and trichlorofurans, which are the major PCDD/F congeners in bleached (partial ClO{sub 2} substitution) kraft pulp mill effluent, with those of TCDD/F. 2,8-D{sub 2}CDF and 2,3,8,-T{sub 3}CDF were rapidly eliminated with half-lives (t{sub 1/2}) of 6 to 1 0 days for both compounds. By contrast TCDF and TCDD were slowly eliminated by the trout (t{sub 1/2} = 70 and 80 d, respectively). Biomagnification factors for 2,8-D{sub 2}CDF and 2,3,8,-T{sub 3}CDF were < 0.1 and there was evidence of extensive transformation of T{sub 3}CDF to polar degradation products. P450 MFO (EROD) activities in fish exposed to 100 or 300 ng/g of 2,3,8,-T{sub 3}CDF were 5 to 15-fold elevated (over controls); 2,8-D{sub 2}CDF exposure had no effect. Exposure to 413 pg/g TCDD in food resulted in 4-fold elevation in EROD after 30 days corresponding to a concentration in muscle of 120 pg/g wet wt. MFO activity returned to control levels 24 days after cessation of exposure to 2,3,8,-T{sub 3}CDF and 120 days after exposure to TCDD.

  2. Phenyl derivative of pyranocoumarin precludes Fusarium oxysporum f.sp. Lycopersici infection in Lycopersicon esculentum via induction of enzymes of the phenylpropanoid pathway.

    PubMed

    Sangeetha, S; Sarada, D V L

    2015-01-01

    Binding of phenyl derivative of pyranocoumarin (PDP) modulated activity of fungal endopolygalacturonase in silico. Induced fit docking study of PDP with endopolygalacturonase (1HG8) showed a bifurcated hydrogen bond interaction with the protein at Lys 244 with a docking score of -3.6 and glide energy of -37.30 kcal/mol. Docking with endopolygalacturonase II (1CZF) resulted hydrogen bond formation with Lys 258 with a docking score of -2.3 and glide energy of -30.42 kcal/mol. It was hypothesized that this modulation favors accumulation of cell wall fragments (oligogalacturonides) which act as elicitors of plant defense responses. In order to prove the same, in vivo studies were carried out using a formulation developed from PDP (PDP 5EC) on greenhouse grown Lycopersicon esculentum L. The formulation was effective at different concentrations in reduction of seed infection, improvement of vigor and control of Fusarium oxysporum f.sp. lycopersici infection in L. esculentum. At a concentration of 2 %, PDP 5EC significant reduction in seed infection (95.83 %), improvement in seed vigor (64.31 %) and control of F. oxysporum f.sp. lycopersici infection (96.15 %) were observed. Further application of PDP 5EC to L. esculentum challenged with F. oxysporum f.sp. lycopersici significantly increased the activity of enzymes of the phenylpropanoid pathway, namely, peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), and enhanced the total phenolic content when compared to the control. PMID:25374140

  3. cis-Terpin Hydrate Metabolism by a Brevibacterium: Patterns of Enzyme Induction, and Accumulation of α-Terpineol in Growth Media

    PubMed Central

    Baum, Robert H.; Marr, Eleanor K.

    1972-01-01

    A brevibacterium, strain TH-4, previously isolated by aerobic enrichment on the monocyclic monoterpenoid cis-terpin hydrate as a sole carbon and energy source, was found to grow on α-terpineol and on a number of common sugars and organic acids. Oxidation of these terpenoids was shown to occur via an induced enzyme system, as measured manometrically by oxygen uptake and prevention of protein synthesis with chloramphenicol or puromycin. Oxidation of terpin hydrate by cell suspensions appeared to be coincidentally induced by growth on α-terpineol, and oxidation of α-terpineol similarly appeared to be induced by growth on terpin hydrate. Culture fluids in which the TH-4 organism was grown at the expense of cis-terpin hydrate were found to contain (−)-α-terpineol in combined butanol-ether extracts. The isolated compound was shown to be chromatographically and spectrophotometrically identical to an authentic sample of α-terpineol. The stereospecificity of an enzymatic dehydration of terpin hydrate to α-terpineol is considered. PMID:4336108

  4. Induction of CYP26A1 by Metabolites of Retinoic Acid: Evidence That CYP26A1 Is an Important Enzyme in the Elimination of Active Retinoids

    PubMed Central

    Topletz, Ariel R.; Tripathy, Sasmita; Foti, Robert S.; Shimshoni, Jakob A.; Nelson, Wendel L.

    2015-01-01

    All-trans-retinoic acid (atRA), the active metabolite of vitamin A, induces gene transcription via binding to nuclear retinoic acid receptors (RARs). The primary hydroxylated metabolites formed from atRA by CYP26A1, and the subsequent metabolite 4-oxo-atRA, bind to RARs and potentially have biologic activity. Hence, CYP26A1, the main atRA hydroxylase, may function either to deplete bioactive retinoids or to form active metabolites. This study aimed to determine the role of CYP26A1 in modulating RAR activation via formation and elimination of active retinoids. After treatment of HepG2 cells with atRA, (4S)-OH-atRA, (4R)-OH-atRA, 4-oxo-atRA, and 18-OH-atRA, mRNAs of CYP26A1 and RARβ were increased 300- to 3000-fold, with 4-oxo-atRA and atRA being the most potent inducers. However, >60% of the 4-OH-atRA enantiomers were converted to 4-oxo-atRA in the first 12 hours of treatment, suggesting that the activity of the 4-OH-atRA was due to 4-oxo-atRA. In human hepatocytes, atRA, 4-OH-atRA, and 4-oxo-atRA induced CYP26A1 and 4-oxo-atRA formation was observed from 4-OH-atRA. In HepG2 cells, 4-oxo-atRA formation was observed even in the absence of CYP26A1 activity and this formation was not inhibited by ketoconazole. In human liver microsomes, 4-oxo-atRA formation was supported by NAD+, suggesting that 4-oxo-atRA formation is mediated by a microsomal alcohol dehydrogenase. Although 4-oxo-atRA was not formed by CYP26A1, it was depleted by CYP26A1 (Km = 63 nM and intrinsic clearance = 90 μl/min per pmol). Similarly, CYP26A1 depleted 18-OH-atRA and the 4-OH-atRA enantiomers. These data support the role of CYP26A1 to clear bioactive retinoids, and suggest that the enzyme forming active 4-oxo-atRA may be important in modulating retinoid action. PMID:25492813

  5. Inhibition of ROS-induced apoptosis in endothelial cells by nitrone spin traps via induction of phase II enzymes and suppression of mitochondria-dependent pro-apoptotic signaling

    PubMed Central

    Das, Amlan; Gopalakrishnan, Bhavani; Voss, Oliver H.; Doseff, Andrea I.; Villamena, Frederick A.

    2012-01-01

    Oxidative stress is the main etiological factor behind the pathogenesis of various diseases including inflammation, cancer, cardiovascular and neurodegenerative disorders. Due to the spin trapping abilities and various pharmacological properties of nitrones, their application as therapeutic agent has been gaining attention. Though the antioxidant properties of the nitrones are well known, the mechanisms by which they modulate the cellular defense machinery against oxidative stress is not well investigated and requires further elucidation. Here, we have investigated the mechanisms of cytoprotection of the nitrone spin traps against oxidative stress in bovine aortic endothelial cells (BAEC). Cytoprotective properties of both the cyclic nitrone 5,5-dimethyl-pyrroline N-oxide (DMPO) and linear nitrone alpha-phenyl N-tert-butyl nitrone (PBN) against H2O2-induced cytoxicity were investigated. Preincubation of BAEC with PBN or DMPO resulted in the inhibition of H2O2–mediated cytotoxicity and apoptosis. Nitrone-treatment resulted in the induction and restoration of phase II antioxidant enzymes via nuclear translocation of NF-E2-related factor 2 (Nrf-2) in oxidatively-challenged cells. Furthermore, the nitrones were found to inhibit the mitochondrial depolarization and subsequent activation of caspase-3 induced by H2O2. Significant down-regulation of the pro-apoptotic proteins p53 and Bax, and up-regulation of the anti-apoptotic proteins Bcl-2 and p-Bad were observed when the cells were preincubated with the nitrones prior to H2O2–treatment. It was also observed that Nrf-2 silencing completely abolished the protective effects of nitrones. Hence, these findings suggest that nitrones confer protection to the endothelial cells against oxidative stress by modulating phase II antioxidant enzymes and subsequently inhibiting mitochondria-dependent apoptotic cascade. PMID:22580046

  6. Enzyme markers

    MedlinePlus

    ... or defects passed down through families (inherited) can affect how enzymes work. Some enzymes are affected by several genes. Test results are usually reported as a percentage of normal enzyme activity.

  7. Induction voidmeter

    DOEpatents

    Anderson, Thomas T.; Roop, Conard J.; Schmidt, Kenneth J.; Brewer, John

    1986-01-01

    An induction voidmeter for detecting voids in a conductive fluid may comprise: a four arm bridge circuit having two adjustable circuit elements connected as opposite arms of said bridge circuit, an input branch, and an output branch; two induction coils, bifilarly wound together, connected as the remaining two opposing arms of said bridge circuit and positioned such that the conductive fluid passes through said coils; applying an AC excitation signal to said input branch; and detecting the output signal generated in response to said excitation signal across said output branch. The induction coils may be located outside or inside a non-magnetic pipe containing the conductive fluid.

  8. Induction voidmeter

    DOEpatents

    Anderson, T.T.; Roop, C.J.; Schmidt, K.J.; Brewer, J.

    1983-12-21

    An induction voidmeter for detecting voids in a conductive fluid may comprise: a four arm bridge circuit having two adjustable circuit elements connected as opposite arms of said bridge, an input branch, and an output branch; two induction coils, bifilarly wound together, connected as the remaining two opposing arms of said bridge circuit and positioned such that the conductive fluid passes through said coils; means for applying an AC excitation signal to said input branch; and means for detecting the output signal generated in response to said excitation signal across said output branch. The induction coils may be located outside or inside a non-magnetic pipe containing the conductive fluid.

  9. Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Moe, Owen; Cornelius, Richard

    1988-01-01

    Conveys an appreciation of enzyme kinetic analysis by using a practical and intuitive approach. Discusses enzyme assays, kinetic models and rate laws, the kinetic constants (V, velocity, and Km, Michaels constant), evaluation of V and Km from experimental data, and enzyme inhibition. (CW)

  10. Enzyme Informatics

    PubMed Central

    Alderson, Rosanna G.; Ferrari, Luna De; Mavridis, Lazaros; McDonagh, James L.; Mitchell, John B. O.; Nath, Neetika

    2012-01-01

    Over the last 50 years, sequencing, structural biology and bioinformatics have completely revolutionised biomolecular science, with millions of sequences and tens of thousands of three dimensional structures becoming available. The bioinformatics of enzymes is well served by, mostly free, online databases. BRENDA describes the chemistry, substrate specificity, kinetics, preparation and biological sources of enzymes, while KEGG is valuable for understanding enzymes and metabolic pathways. EzCatDB, SFLD and MACiE are key repositories for data on the chemical mechanisms by which enzymes operate. At the current rate of genome sequencing and manual annotation, human curation will never finish the functional annotation of the ever-expanding list of known enzymes. Hence there is an increasing need for automated annotation, though it is not yet widespread for enzyme data. In contrast, functional ontologies such as the Gene Ontology already profit from automation. Despite our growing understanding of enzyme structure and dynamics, we are only beginning to be able to design novel enzymes. One can now begin to trace the functional evolution of enzymes using phylogenetics. The ability of enzymes to perform secondary functions, albeit relatively inefficiently, gives clues as to how enzyme function evolves. Substrate promiscuity in enzymes is one example of imperfect specificity in protein-ligand interactions. Similarly, most drugs bind to more than one protein target. This may sometimes result in helpful polypharmacology as a drug modulates plural targets, but also often leads to adverse side-effects. Many cheminformatics approaches can be used to model the interactions between druglike molecules and proteins in silico. We can even use quantum chemical techniques like DFT and QM/MM to compute the structural and energetic course of enzyme catalysed chemical reaction mechanisms, including a full description of bond making and breaking. PMID:23116471

  11. Enzymes, Industrial

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enzymes serve key roles in numerous biotechnology processes and products that are commonly encountered in the forms of food and beverages, cleaning supplies, clothing, paper products, transportation fuels, pharmaceuticals, and monitoring devices. Enzymes can display regio- and stereo-specificity, p...

  12. Understanding Enzymes.

    ERIC Educational Resources Information Center

    Sinnott, M. L.

    1979-01-01

    Describes the way enzymes operate through reaction energetics, and explains that most of the catalytic power of enzymes lies in the strong noncovalent forces responsible for initial binding of substrate, which are only manifested at the transition state of the reaction. (Author/GA)

  13. Soil Enzymes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The functionality and resilience of natural and managed ecosystems mainly rely on the metabolic abilities of microbial communities, the main source of enzymes in soils. Enzyme mediated reactions are critical in the decomposition of organic matter, cycling of nutrients, and in the breakdown of herbic...

  14. Induction machine

    DOEpatents

    Owen, Whitney H.

    1980-01-01

    A polyphase rotary induction machine for use as a motor or generator utilizing a single rotor assembly having two series connected sets of rotor windings, a first stator winding disposed around the first rotor winding and means for controlling the current induced in one set of the rotor windings compared to the current induced in the other set of the rotor windings. The rotor windings may be wound rotor windings or squirrel cage windings.

  15. Food Enzymes

    ERIC Educational Resources Information Center

    McBroom, Rachel; Oliver-Hoyo, Maria T.

    2007-01-01

    Many students view biology and chemistry as two unrelated, separate sciences; how these courses are generally taught in high schools may do little to change that impression. The study of enzymes provide a great opportunity for both biology and chemistry teachers to share with students the interdisciplinary nature of science. This article describes…

  16. Zinc Enzymes.

    ERIC Educational Resources Information Center

    Bertini, I.; And Others

    1985-01-01

    Discusses the role of zinc in various enzymes concerned with hydration, hydrolysis, and redox reactions. The binding of zinc to protein residues, properties of noncatalytic zinc(II) and catalytic zinc, and the reactions catalyzed by zinc are among the topics considered. (JN)

  17. Primary enzyme quantitation

    DOEpatents

    Saunders, G.C.

    1982-03-04

    The disclosure relates to the quantitation of a primary enzyme concentration by utilizing a substrate for the primary enzyme labeled with a second enzyme which is an indicator enzyme. Enzyme catalysis of the substrate occurs and results in release of the indicator enzyme in an amount directly proportional to the amount of primary enzyme present. By quantifying the free indicator enzyme one determines the amount of primary enzyme present.

  18. Mediated effect of ultrasound treated Diclofenac on mussel hemocytes: First evidence for the involvement of respiratory burst enzymes in the induction of DCF-mediated unspecific mode of action.

    PubMed

    Toufexi, Eirini; Dailianis, Stefanos; Vlastos, Dimitris; Manariotis, Ioannis D

    2016-06-01

    The present study investigates the toxic behavior of diclofenac (DCF) before and after its ultrasound (US) treatment, as well as the involvement of intracellular target molecules, such as NADPH oxidase and NO synthase, in the DCF-induced adverse effects on hemocytes of mussel Mytilus galloprovincialis. In this context, appropriate volumes (350 and 500mL) of DCF solutions (at concentrations of 2, 2.5, 5 and 10mgL(-1)) were treated under different ultrasound operating conditions (frequency at 582 and 862kHz, electric power density at 133 and 167W) for assessing US method efficiency. In parallel, DCF and US DCF-mediated cytotoxic (in terms of cell viability measured with the use of neutral red uptake/NRU method), oxidative (in terms of superoxide anions/(.)O2(-), nitric oxides such as NO2(-) and lipid peroxidation products, such as malondialdehyde/MDA content) and genotoxic (DNA damage measured by the use of Comet assay method) effects were investigated in hemocytes exposed for 1h to 5, 10 and 100ngL(-1) and 1, 10 and 20μgL(-1) of DCF. The involvement of NADPH oxidase and NO synthase to the DCF-induced toxicity was further investigated by the use of 10μΜ L-NAME, a NO synthase inhibitor and 10μΜ DPI, a NADPH oxidase inhibitor. According to the results, 350mL of 2mgL(-1) DCF showed higher degradation (>50%) under 167W electric power density and frequency at 862kHz for 120min, compared to degradation in all other cases, followed by a significant elimination of its toxicity. Specifically, US DCF-treated hemocytes showed a significant attenuation of DCF-mediated cytotoxic, oxidative and genotoxic effects, which appeared to be caused by NADPH oxidase and NO synthase activation, since their inhibition was followed by a significant elimination of (.)O2(-) and NO2(-) generation and the concomitant oxidative damage within cells. The results of the present study showed for the first time that unspecific mode of action of DCF, associated with the induction of NADPH oxidase

  19. Light/dark modulation of enzyme activity in photosynthesis

    SciTech Connect

    Anderson, L.E.; Ashton, A.R.; Mohamed, A.H.; Scheibe, R.

    1982-02-01

    In photosynthetic species ranging from cyanobacteria to higher plants, many enzymes are light modulated. Most of the known light modulated enzymes are chloroplastic. Four mechanisms of modulation have been proposed. One function of light modulation is probably the autocatalytic build-up of reductive pentose phosphate cycle intermediates during the induction period of photosynthetic CO/sub 2/ fixation.

  20. Electromagnetic induction methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electromagnetic induction geophysical methods are finding greater and greater use for agricultural purposes. Electromagnetic induction methods measure the electrical conductivity (or resistivity) for a bulk volume of soil directly beneath the surface. An instrument called a ground conductivity meter...

  1. Sequential inductive learning

    SciTech Connect

    Gratch, J.

    1996-12-31

    This article advocates a new model for inductive learning. Called sequential induction, it helps bridge classical fixed-sample learning techniques (which are efficient but difficult to formally characterize), and worst-case approaches (which provide strong statistical guarantees but are too inefficient for practical use). Learning proceeds as a sequence of decisions which are informed by training data. By analyzing induction at the level of these decisions, and by utilizing the only enough data to make each decision, sequential induction provides statistical guarantees but with substantially less data than worst-case methods require. The sequential inductive model is also useful as a method for determining a sufficient sample size for inductive learning and as such, is relevant to learning problems where the preponderance of data or the cost of gathering data precludes the use of traditional methods.

  2. Induction Therapy for Thymoma.

    PubMed

    Ahmad, Usman; Huang, James

    2016-08-01

    Thymomas are uncommon tumors that can present as locally advanced tumors in approximately 30% of the patients. Stage and complete resection are the strongest prognostic factors. For locally advanced tumors, induction treatment may improve the ability to achieve a complete resection. Combination treatment with cisplatin, doxorubicin, and cyclophosphamide is the most commonly used induction regimen. Similar rates of resectability are noted with the use of induction chemotherapy and chemoradiation therapy; however, more tumor necrosis is noted with the addition of radiation. PMID:27427527

  3. Effects of induction and age-dependent enzyme expression on lung bioavailability, metabolism, and DNA binding of urban air particulate-absorbed benzo[a]pyrene, 2-nitrofluorene, and 3-amino-1,4-dimethyl-5H-pyridol-(4,3)-indole.

    PubMed Central

    Gøtze, J P; Lindeskog, P; Törnquist, C S

    1994-01-01

    The effect of interactions between urban air particulates (UAP) and carcinogens on bioavailability, metabolism, and DNA binding was studied in the isolated perfused and ventilated rat lung. The availability of benzo[a]pyrene (B[a]P) varied from 29 to 60% after intratracheal doses of carcinogen particulates dissolving extremely slow and fast, respectively. Several cytochrome P450 enzyme (P450) inducers acting as 2,3,7,8-tetrachlorodibenzo[p]dioxin-receptor ligands have been identified in UAP extracts. beta-Naphthoflavone (BNF) was used to study how P450 induction alters the lung metabolism of carcinogens. Pretreatment increased the lung clearance for B[a]P 8-fold and for 2-nitrofluorene (2NF) by a factor of four from 0.55 +/- 0.06 ml/min to 2.37 +/- 0.62 ml/min. Studies with the intact lung and with isolated lung cells show that carcinogen metabolism and pharmacokinetics depend both on the route of exposure and dosage and on the distribution of specific enzymes. A cytochrome P450IIB1 enzyme was detected in lung epithelial cells where it catalyzes 9-hydroxylation of 2NF. This rat lung 2NF-9-hydroxylation capacity increases in parallel with the age dependent up-regulation of lung P450IIB1 expression. Both human and rat lung tissue have the capacity to form 9-hydroxy-2-nitrofluorene (9-OH-2NF) that is mutagenic. A BNF-inducible P450IA1 was detected in endothelial and alveolar type II cells. Consequently, aromatic hydroxylation dominated when 2NF was dosed directly into the lung circulation. Pretreatment of rats with BNF before intratracheal B[a]P dosage induced lung cytochrome P450IA1. The 7,8-dihydroxy-9,10-oxybenzo[a]pyrene-deoxyguanosine adduct and the total lung DNA adduct levels increased significantly from a peak level of 75 +/- 8 to 151 +/- 19 fmole/mg DNA in lungs from control and BNF pretreated rats, respectively. 3-Amino-1,4-dimethyl-5H-pyridol-(4,3)-indole (TRP-P1) is a potent mutagen and carcinogen identified in UAP extracts. Dietary BNF pretreatment of

  4. Insolubilization process increases enzyme stability

    NASA Technical Reports Server (NTRS)

    Billingham, J.; Lyn, J.

    1971-01-01

    Enzymes complexed with polymeric matrices contain properties suggesting application to enzyme-controlled reactions. Stability of insolubilized enzyme derivatives is markedly greater than that of soluble enzymes and physical form of insolubilized enzymes is useful in column and batch processes.

  5. Induction: Making the Leap

    ERIC Educational Resources Information Center

    Ling, Lorraine M.

    2009-01-01

    This article provides a critical examination of a variety of approaches to induction focusing especially upon Australia and other Pacific Rim countries. The question of the purposes induction serves for graduate teachers, experienced teachers and education systems is addressed in terms of whether it is a technical exercise which preserves the…

  6. The ENZYME data bank.

    PubMed Central

    Bairoch, A

    1994-01-01

    The ENZYME data bank is a repository of information relative to the nomenclature of enzymes. It is primarily based on the recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB) and it contains the following data for each type of characterized enzyme for which an EC (Enzyme Commission) number has been provided: EC number Recommended name Alternative names (if any) Catalytic activity Cofactors (if any) Pointers to the SWISS-PROT protein sequence entrie(s) that correspond to the enzyme (if any) Pointers to human disease(s) associated with a deficiency of the enzyme (if any). PMID:7937072

  7. Principles of Induction Accelerators

    NASA Astrophysics Data System (ADS)

    Briggs*, Richard J.

    The basic concepts involved in induction accelerators are introduced in this chapter. The objective is to provide a foundation for the more detailed coverage of key technology elements and specific applications in the following chapters. A wide variety of induction accelerators are discussed in the following chapters, from the high current linear electron accelerator configurations that have been the main focus of the original developments, to circular configurations like the ion synchrotrons that are the subject of more recent research. The main focus in the present chapter is on the induction module containing the magnetic core that plays the role of a transformer in coupling the pulsed power from the modulator to the charged particle beam. This is the essential common element in all these induction accelerators, and an understanding of the basic processes involved in its operation is the main objective of this chapter. (See [1] for a useful and complementary presentation of the basic principles in induction linacs.)

  8. Progress in Induction Linacs

    SciTech Connect

    Caporaso, G J

    2000-09-27

    This presentation will be a broad survey of progress in induction technology over the past four years. Much work has been done on accelerators for hydrodynamic test radiography and other applications. Solid-state pulsers have been developed which can provide unprecedented flexibility and precision in pulse format and accelerating voltage for both ion and electron induction machines. Induction linacs can now be built which can operate with MHz repetition rates. Solid-state technology has also made possible the development of fast kickers for precision control of high current beams. New insulator technology has been developed which will improve conventional induction linacs in addition to enabling a new class of high gradient induction linacs.

  9. Enzyme Therapy: Current Perspectives.

    PubMed

    UmaMaheswari, Thiyagamoorthy; Hemalatha, Thiagarajan; Sankaranarayanan, Palavesam; Puvanakrishnan, Rengarajulu

    2016-01-01

    Enzymes control all metabolic processes in human system from simple digestion of food to highly complex immune response. Physiological reactions occuring in healthy individuals are disturbed when enzymes are deficient or absent. Enzymes are administered for normalizing biological function in certain pathologies. Initially, crude proteolytic enzymes were used for the treatment of gastrointestinal disorders. Recent advances have enabled enzyme therapy as a promising tool in the treatment of cardiovascular, oncological and hereditary diseases. Now, a spectrum of other diseases are also covered under enzyme therapy. But, the available information on the use of enzymes as therapeutic agents for different diseases is scanty. This review details the enzymes which have been used to treat various diseases/disorders. PMID:26891548

  10. Contributions of Human Enzymes in Carcinogen Metabolism

    PubMed Central

    Rendic, Slobodan; Guengerich, F. Peter

    2012-01-01

    Considerable support exists for roles of metabolism in modulating the carcinogenic properties of chemicals. In particular, many of these compounds are procarcinogens that require activation to electrophilic forms to exert genotoxic effects. We systematically analyzed the existing literature on metabolism of carcinogens by human enzymes, which has been developed largely in the past 25 years. The metabolism and especially bioactivation of carcinogens are dominated by cytochrome P450 enzymes (66% of bioactivations). Within this group, six P450s—1A1, 1A2, 1B1, 2A6, 2E1, and 3A4—accounted for 77% of the P450 activation reactions. The roles of these P450s can be compared with those estimated for drug metabolism and should be considered in issues involving enzyme induction, chemoprevention, molecular epidemiology, inter-individual variations, and risk assessment. PMID:22531028

  11. Developments in Enzyme Technology.

    ERIC Educational Resources Information Center

    Chaplin, M. F.

    1984-01-01

    Enzyme technology has a well-established industrial base, with applications that have survived competition. The most prominent applications of enzymes in biotechnology are examined with an explanation of some theoretical background. Topics include extending an enzyme's useful life, partition and diffusion, industrial uses, and therapeutic uses.…

  12. The induction motor

    NASA Astrophysics Data System (ADS)

    Redinz, José Arnaldo

    2015-09-01

    We obtain analytical expressions for the torques and angular speed of an induction motor with a simple geometry, resembling the geometry of the first induction motor investigated by Arago in 1824. The rotor is a conducting disc rotating between the magnetic poles of two off-axis solenoids, displaced in space by 90^\\circ from each other. We apply our results to discuss a theory for the ubiquitous electromechanical watt-hour meter. For comparison of the theoretical result for the angular speed with measurements, we propose a simple experiment in which an induction motor with an aluminum disc rotor is constructed.

  13. Review of induction LINACS

    SciTech Connect

    Faltens, A.; Keefe, D.

    1981-10-01

    There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents.

  14. Direct reading inductance meter

    NASA Technical Reports Server (NTRS)

    Kolby, R. B. (Inventor)

    1977-01-01

    A direct reading inductance meter comprised of a crystal oscillator and an LC tuned oscillator is presented. The oscillators function respectively to generate a reference frequency, f(r), and to generate an initial frequency, f(0), which when mixed produce a difference equal to zero. Upon connecting an inductor of small unknown value in the LC circuit to change its resonant frequency to f(x), a difference frequency (f(r)-f(x)) is produced that is very nearly a linear function of the inductance of the inductor. The difference frequency is measured and displayed on a linear scale in units of inductance.

  15. Induction melter apparatus

    DOEpatents

    Roach, Jay A [Idaho Falls, ID; Richardson, John G [Idaho Falls, ID; Raivo, Brian D [Idaho Falls, ID; Soelberg, Nicholas R [Idaho Falls, ID

    2008-06-17

    Apparatus and methods of operation are provided for a cold-crucible-induction melter for vitrifying waste wherein a single induction power supply may be used to effect a selected thermal distribution by independently energizing at least two inductors. Also, a bottom drain assembly may be heated by an inductor and may include an electrically resistive heater. The bottom drain assembly may be cooled to solidify molten material passing therethrough to prevent discharge of molten material therefrom. Configurations are provided wherein the induction flux skin depth substantially corresponds with the central longitudinal axis of the crucible. Further, the drain tube may be positioned within the induction flux skin depth in relation to material within the crucible or may be substantially aligned with a direction of flow of molten material within the crucible. An improved head design including four shells forming thermal radiation shields and at least two gas-cooled plenums is also disclosed.

  16. Induction heating coupler

    NASA Technical Reports Server (NTRS)

    Fox, Robert L. (Inventor); Copeland, Carl E. (Inventor); Swaim, Robert J. (Inventor); Coultrip, Robert H. (Inventor); Johnston, David F. (Inventor); Phillips, W. Morris (Inventor); Johnson, Samuel D. (Inventor); Dinkins, James R. (Inventor); Buckley, John D. (Inventor)

    1994-01-01

    An induction heating device includes a handle having a hollow interior and two opposite ends, a wrist connected to one end of the handle, a U-shaped pole piece having two spaced apart ends, a tank circuit including an induction coil wrapped around the pole piece and a capacitor connected to the induction coil, a head connected to the wrist and including a housing for receiving the U-shaped pole piece, the two spaced apart ends of the pole piece extending outwardely beyond the housing, and a power source connected to the tank circuit. When the tank circuit is energized and a susceptor is placed in juxtaposition to the ends of the U-shaped pole piece, the susceptor is heated by induction heating due to magnetic flux passing between the two ends of the pole piece.

  17. DNA damage induction of ribonucleotide reductase.

    PubMed Central

    Elledge, S J; Davis, R W

    1989-01-01

    RNR2 encodes the small subunit of ribonucleotide reductase, the enzyme that catalyzes the first step in the pathway for the production of deoxyribonucleotides needed for DNA synthesis. RNR2 is a member of a group of genes whose activities are cell cycle regulated and that are transcriptionally induced in response to the stress of DNA damage. An RNR2-lacZ fusion was used to further characterize the regulation of RNR2 and the pathway responsible for its response to DNA damage. beta-Galactosidase activity in yeast strains containing the RNR2-lacZ fusion was inducible in response to DNA-damaging agents (UV light, 4-nitroquinoline-1-oxide [4-NQO], and methyl methanesulfonate [MMS]) and agents that block DNA replication (hydroxyurea [HU] and methotrexate) but not heat shock. When MATa cells were arrested in G1 by alpha-factor, RNR2 mRNA was still inducible by DNA damage, indicating that the observed induction can occur outside of S phase. In addition, RNR2 induction was not blocked by the presence of cycloheximide and is therefore likely to be independent of protein synthesis. A mutation, rnr2-314, was found to confer hypersensitivity to HU and increased sensitivity to MMS. In rnr2-314 mutant strains, the DNA damage stress response was found to be partially constitutive as well as hypersensitive to induction by HU but not MMS. The induction properties of RNR2 were examined in a rad4-2 mutant background; in this genetic background, RNR2 was hypersensitive to induction by 4-NQO but not MMS. Induction of the RNR2-lacZ fusion in a RAD(+) strain in response to 4-NQO was not enhanced by the presence of an equal number of rad4-2 cells that lacked the fusion, implying that the DNA damage stress response in cell autonomous. Images PMID:2513480

  18. Doubly fed induction machine

    DOEpatents

    Skeist, S. Merrill; Baker, Richard H.

    2005-10-11

    An electro-mechanical energy conversion system coupled between an energy source and an energy load including an energy converter device having a doubly fed induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer coupled to the energy converter device to control the flow of power or energy through the doubly fed induction machine.

  19. Induction launcher design considerations

    NASA Technical Reports Server (NTRS)

    Driga, M. D.; Weldon, W. F.

    1989-01-01

    New concepts in the design of induction accelerators and their power supplies for space and military applications are discussed. Particular attention is given to a piecewise-rising-frequency power supply in which each elementary generator (normal compulsator or rising frequency generator) has a different base frequency. A preliminary design of a coaxial induction accelerator for a hypersonic real gas facility is discussed to illustrate the concepts described.

  20. Linear induction accelerator

    DOEpatents

    Buttram, M.T.; Ginn, J.W.

    1988-06-21

    A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.

  1. Induction as Knowledge Integration

    NASA Technical Reports Server (NTRS)

    Smith, Benjamin D.; Rosenbloom, Paul S.

    1996-01-01

    Two key issues for induction algorithms are the accuracy of the learned hypothesis and the computational resources consumed in inducing that hypothesis. One of the most promising ways to improve performance along both dimensions is to make use of additional knowledge. Multi-strategy learning algorithms tackle this problem by employing several strategies for handling different kinds of knowledge in different ways. However, integrating knowledge into an induction algorithm can be difficult when the new knowledge differs significantly from the knowledge the algorithm already uses. In many cases the algorithm must be rewritten. This paper presents Knowledge Integration framework for Induction (KII), a KII, that provides a uniform mechanism for integrating knowledge into induction. In theory, arbitrary knowledge can be integrated with this mechanism, but in practice the knowledge representation language determines both the knowledge that can be integrated, and the costs of integration and induction. By instantiating KII with various set representations, algorithms can be generated at different trade-off points along these dimensions. One instantiation of KII, called RS-KII, is presented that can implement hybrid induction algorithms, depending on which knowledge it utilizes. RS-KII is demonstrated to implement AQ-11, as well as a hybrid algorithm that utilizes a domain theory and noisy examples. Other algorithms are also possible.

  2. Induction of labor.

    PubMed

    2000-06-01

    The goal of induction of labor is to achieve vaginal delivery by stimulating uterine contractions before the spontaneous onset of labor. According to the National Center for Health Statistics, the overall rate of induction of labor in the United States has increased from 90 per 1,000 live births in 1989 to 184 per 1,000 live births in 1997 (I). Generally, induction of labor has merit as a therapeutic option when the benefits of expeditious delivery outweigh the risks of continuing the pregnancy. The benefits of labor induction must be weighed against the potential maternal or fetal risks associated with this procedure. The purpose of this bulletin is to review current methods for cervical ripening and induction of labor and to summarize the effectiveness of these approaches based on appropriately conducted outcomes-based research. These practice guidelines classify the indications for and contraindications to induction of labor, describe the various agents used for cervical ripening, cite methods used to induce labor, and outline the requirements for the safe clinical use of the various methods of inducing labor. PMID:10979741

  3. ARSENIC INDUCTION OF HEME OXYGENASE AS A BIOMARKER

    EPA Science Inventory


    Useful biomarkers of arsenic effects in both experimental animals and humans are needed. Arsenate and arsenite are good inducers of rat hepatic and renal heme oxygenase (HO); monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) are not. Therefore, HO enzyme induction ...

  4. Induction in a Modular Learner.

    ERIC Educational Resources Information Center

    Carroll, Susanne E.

    2002-01-01

    Presents a theory of inductive learning--Autonomous Induction Theory--a form of induction that takes place within the autonomous and modular representational systems of the language faculty. Argues that Autonomous Induction Theory is constrained enough to be taken seriously as a plausible approach to explaining second language acquisition.…

  5. Enzymes for improved biomass conversion

    DOEpatents

    Brunecky, Roman; Himmel, Michael E.

    2016-02-02

    Disclosed herein are enzymes and combinations of the enzymes useful for the hydrolysis of cellulose and the conversion of biomass. Methods of degrading cellulose and biomass using enzymes and cocktails of enzymes are also disclosed.

  6. Mothers' experiences of induction

    PubMed Central

    Cartwright, Ann

    1977-01-01

    Mothers of a random sample of 2182 legitimate live births were interviewed about their experiences of pregnancy, labour, and delivery. Of these, 24% reported that their labours were induced, and data about this from a subsample of mothers tallied with information obtained through the doctors in charge in 88% of cases. All but 3% of the mothers who were induced perceived some medical reason for the induction. The proportion of inductions in the 24 study areas ranged from 6% to 39%. A relatively small proportion of labours in “teaching” hospitals, small hospitals with less than 100 beds, and GP maternity hospitals were induced, but a comparatively high proportion of private patients had an induction. There was no clear association between induction and the mother's age or parity. Despite being given more pain relief, those who were induced reported similar intensities of pain during the first and second stages of labour to those whose labour started spontaneously; they also reported that they had “bad pains” for a similar period. The period they had contractions was shorter for the induced than for those starting spontaneously, and the intensity of pain at delivery was rated somewhat less by those who were induced. There was no difference between induced babies and others in the proportion who were held by their mothers immediately after their birth. Two-fifths of the mothers who were induced would have liked more information about induction; and a similar proportion said they had not discussed induction with a doctor, midwife, or nurse during their pregnancy. Only 17% of the mothers who had an induction said they would prefer to be induced if they had another baby. This contrasts with 63% of those who had epidural analgesia who would opt for the same procedure next time, while 83% of those who had had a baby in hospital, and 91% of those having had a home birth, would want their next baby in the same type of place. PMID:912282

  7. Catalyzed enzyme electrodes

    DOEpatents

    Zawodzinski, Thomas A.; Wilson, Mahlon S.; Rishpon, Judith; Gottesfeld, Shimshon

    1993-01-01

    An enzyme electrode is prepared with a composite coating on an electrical conductor. The composite coating is formed from a casting solution of a perfluorosulfonic acid polymer, an enzyme, and a carbon supported catalyst. The solution may be cast directly on the conductor surface or may be formed as a membrane and applied to the surface. The perfluorosulfonic acid ionomer formed from the casting solution provides an insoluble biocompatible protective matrix for the enzyme and acts to retain the enzyme for long term availability in the electrode structure. The carbon supported catalyst provides catalytic sites throughout the layer for the oxidation of hydrogen peroxide from the enzyme reactions. The carbon support then provides a conductive path for establishing an electrical signal to the electrical conductor. In one embodiment, the electrical conductor is a carbon cloth that permits oxygen or other gas to be introduced to the perfluorosulfonic polymer to promote the enzyme reaction independent of oxygen in the solution being tested.

  8. Rational enzyme redesign

    SciTech Connect

    Ornstein, R.L.

    1994-05-01

    Protein engineering is first a means of elucidating structure-function relations in an enzyme, and second, a means of changing a protein to make it serve a different, but generally related, purpose. In principle, one may change the functional characteristics of an enzyme by altering its substrate specificity, kinetics, optimum range of activity, and chemical mechanism. Obviously one cannot make all possible combinations of amino acid changes for even the smallest enzyme, so the essential question is which changes to make. The intent of rational protein/enzyme redesign is to alter a protein/enzyme in a timely and premeditated fashion. This article provides an outline of the process of rational enzyme redesign.

  9. Magnetically responsive enzyme powders

    NASA Astrophysics Data System (ADS)

    Pospiskova, Kristyna; Safarik, Ivo

    2015-04-01

    Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (-20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties.

  10. Chloroplast and Cytoplasmic Enzymes

    PubMed Central

    Anderson, Louise E.; Pacold, Ivan

    1972-01-01

    Several peaks of aldolase activity are found in the isoelectric focusing pattern of pea (Pisum sativum) leaf chloroplast extracts. One peak, separated by 0.5 pH unit from the major chloroplast aldolase peak, is found when cytoplasmic extracts are focused. The chloroplast and cytoplasmic enzymes have a pH 7.4 optimum with fructose 1,6-diphosphate. The Michaelis constant for fructose-1,6-diphosphate is 19 μM for the chloroplast, 21 μM for the cytoplasmic enzyme, and for sedoheptulose 1,7-diphosphate, 8 μM for the chloroplast enzyme, 18 μM for the cytoplasmic enzyme. Both enzymes are inhibited by d-glyceraldehyde 3-phosphate and by ribulose 1,5-diphosphate. The similarity in the catalytic properties of the isoenzymes suggests that both enzymes have an amphibolic role in carbon metabolism in the green leaf. PMID:16657968

  11. Catalyzed enzyme electrodes

    SciTech Connect

    Zawodzinski, T.A.; Wilson, M.S.; Rishpon, J.; Gottesfeld, S.

    1992-12-31

    An enzyme electrode is prepared with a composite coating on an electrical conductor. The composite coating is formed from a casting solution of a perfluorosulfonic acid, polymer, an enzyme, and a carbon supported catalyst. The solution may be cast directly on the conductor surface or may be formed as a membrane and applied to the surface. The perfluorosulfonic acid ionomer formed from the casting solution provides an insoluble biocompatible protective matrix for the enzyme and acts to retain the enzyme for long term availability in the electrode structure. The carbon supported catalyst provides catalytic sites throughout the layer for the oxidation of hydrogen peroxide from the enzyme reactions. The carbon support then provides a conductive path for establishing an electrical signal to the electrical conductor. In one embodiment, the electrical conductor is a carbon cloth that permits oxygen or other gas to be introduced to the perfluorosulfonic polymer to promote the enzyme reaction independent of oxygen in the solution being tested.

  12. Catalyzed enzyme electrodes

    SciTech Connect

    Zawodzinski, T.A.; Wilson, M.S.; Rishpon, J.; Gottesfeld, S.

    1993-07-13

    An enzyme electrode is prepared with a composite coating on an electrical conductor. The composite coating is formed from a casting solution of a perfluorosulfonic acid polymer, an enzyme, and a carbon supported catalyst. The solution may be cast directly on the conductor surface or may be formed as a membrane and applied to the surface. The perfluorosulfonic acid ionomer formed from the casting solution provides an insoluble biocompatible protective matrix for the enzyme and acts to retain the enzyme for long term availability in the electrode structure. The carbon supported catalyst provides catalytic sites throughout the layer for the oxidation of hydrogen peroxide from the enzyme reactions. The carbon support then provides a conductive path for establishing an electrical signal to the electrical conductor. In one embodiment, the electrical conductor is a carbon cloth that permits oxygen or other gas to be introduced to the perfluorosulfonic polymer to promote the enzyme reaction independent of oxygen in the solution being tested.

  13. Human Photoreactivating Enzyme

    PubMed Central

    Sutherland, J. C.; Sutherland, B. M.

    1975-01-01

    The action spectrum for photoreactivation by enzymes from human leukocytes and fibroblasts extends from 300 to approximately 600 nm with a maximum near 400 nm. The ability of the human enzymes to utilize light of wavelengths greater than 500 nm suggested that yellow or gold lights conventionally used as safelights for photoreactivation might serve as sources of photoreactivating light for these enzymes. Experiments using lights with a range of spectral outputs confirm that the standard yellow “safe” lights do produce photoreactivation by the human but not the Escherichia coli enzyme. PMID:19211015

  14. Adenylate-forming enzymes.

    PubMed

    Schmelz, Stefan; Naismith, James H

    2009-12-01

    Thioesters, amides, and esters are common chemical building blocks in a wide array of natural products. The formation of these bonds can be catalyzed in a variety of ways. For chemists, the use of an activating group is a common strategy and adenylate enzymes are exemplars of this approach. Adenylating enzymes activate the otherwise unreactive carboxylic acid by transforming the normal hydroxyl leaving group into adenosine monophosphate. Recently there have been a number of studies of such enzymes and in this review we suggest a new classification scheme. The review highlights the diversity in enzyme fold, active site architecture, and metal coordination that has evolved to catalyze this particular reaction. PMID:19836944

  15. Nanostructures for enzyme stabilization

    SciTech Connect

    Kim, Jungbae; Grate, Jay W.; Wang, Ping

    2006-02-02

    The last decade has witnessed notable breakthroughs in nanotechnology with development of various nanostructured materials such as mesoporous materials and nanoparticles. These nanostructures have been used as a host for enzyme immobilization via various approaches, such as enzyme adsorption, covalent attachment, enzyme encapsulation, and sophisticated combinations of methods. This review discusses the stabilization mechanisms behind these diverse approaches; such as confinement, pore size and volume, charge interaction, hydrophobic interaction, and multipoint attachment. In addition, we will introduce recent rigorous approaches to improve the enzyme stability in these nanostructures or develop new nanostructures for the enzyme stabilization. Especially, we will introduce our recent invention of a nanostructure, called single enzyme nanoparticles (SENs). In the form of SENs, each enzyme molecule is surrounded with a nanometer scale network, resulting in stabilization of enzyme activity without any serious limitation for the substrate transfer from solution to the active site. SENs can be further immobilized into mesoporous silica with a large surface area, providing a hierarchical approach for stable, immobilized enzyme systems for various applications, such as bioconversion, bioremediation, and biosensors.

  16. Wrapper Induction Software

    Energy Science and Technology Software Center (ESTSC)

    2011-08-18

    Wrapper Induction is a software package that allows for unsupervised, semi-supervised, and manual extraction of social media data independent of language or site architecture. A large range of blog formats is available to individuals as means of publishing data to the internet. Blogs are a source of rich information for analysts. With a growing volume of information and blog engines, there is an increased need for automatic or semi-automatic extraction of that data for processingmore » to help deliver results to analysts. Wrapper Induction is designed to automatically or semi-automatically create a template that can be used to harvest blog data from websites. Blogs are in a variety of formats and languages. Wrapper Induction creates a template and extracts blog data in a way that is independent of a specified blog format or language.« less

  17. Wrapper Induction Software

    SciTech Connect

    2011-08-18

    Wrapper Induction is a software package that allows for unsupervised, semi-supervised, and manual extraction of social media data independent of language or site architecture. A large range of blog formats is available to individuals as means of publishing data to the internet. Blogs are a source of rich information for analysts. With a growing volume of information and blog engines, there is an increased need for automatic or semi-automatic extraction of that data for processing to help deliver results to analysts. Wrapper Induction is designed to automatically or semi-automatically create a template that can be used to harvest blog data from websites. Blogs are in a variety of formats and languages. Wrapper Induction creates a template and extracts blog data in a way that is independent of a specified blog format or language.

  18. Induction powered biological radiosonde

    NASA Technical Reports Server (NTRS)

    Fryer, T. B. (Inventor)

    1980-01-01

    An induction powered implanted monitor for epidurally measuring intracranial pressure and telemetering the pressure information to a remote readout is disclosed. The monitor utilizes an inductance-capacitance (L-C) oscillator in which the C comprises a variable capacitance transducer, one electrode of which is a small stiff pressure responsive diaphragm. The oscillator is isolated from a transmitting tank circuit by a buffer circuit and all electric components in the implanted unit except an input and an output coil are shielded by a metal housing.

  19. Inductive Adder development

    SciTech Connect

    Miller, R.B.; Davis, B.B.; Bayless, J.

    1989-05-01

    TITAN has successfully developed an Inductive Adder for use with a Hewlett-Packard Model 43734A Marx pulser. The unit provides an 800 kV peak output pulse to a modified HP 5081-9551 1 MV x-ray tube. The tube fits into the adder unit, and can thus be remotely operated. It delivers a peak on-axis dose of 35 mR at a one meter distance. Supporting radiography analyses, a description of the inductive adder approach and construction, and detailed test data are presented.

  20. HIGH GRADIENT INDUCTION ACCELERATOR

    SciTech Connect

    Caporaso, G J; Sampayan, S; Chen, Y; Blackfield, D; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2007-06-21

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.

  1. Iteration, Not Induction

    ERIC Educational Resources Information Center

    Dobbs, David E.

    2009-01-01

    The main purpose of this note is to present and justify proof via iteration as an intuitive, creative and empowering method that is often available and preferable as an alternative to proofs via either mathematical induction or the well-ordering principle. The method of iteration depends only on the fact that any strictly decreasing sequence of…

  2. Using Continuity Induction

    ERIC Educational Resources Information Center

    Hathaway, Dan

    2011-01-01

    Here is a technique for proving the fundamental theorems of analysis that provides a unified way to pass from local properties to global properties on the real line, just as ordinary induction passes from local implication (if true for "k", the theorem is true for "k" + 1) to a global conclusion in the natural numbers.

  3. Educational Inductive Gravimeter

    ERIC Educational Resources Information Center

    Nunn, John

    2014-01-01

    A simple inductive gravimeter constructed from a rigid plastic pipe and insulated copper wire is described. When a magnet is dropped through the vertically mounted pipe it induces small alternating voltages. These small signals are fed to the microphone input of a typical computer and sampled at a typical rate of 44.1 kHz using a custom computer…

  4. Enzyme nanoband electrodes

    SciTech Connect

    Wang, J.; Naser, N. ); Renschler, C.L. )

    1993-07-01

    Enzyme nanoelectrodes have been constructed by immobilizing glucose oxidase, alcohol oxidase or tyrosinase onto ultrathin carbon films (of 35-50 nm thickness). The enzyme immobilization is accomplished via entrapment within electropolymerized poly(o-phenylenediamine) coatings. Cyclic voltammetry and controlled-potential amperometry are used to characterize the performance of the new nanoscopic biosensors under different preparation and operation conditions. The resulting electrodes offer convenient and rapid measurements of millimolar substrate concentrations, and (to the best of the authors' knowledge) are the smallest enzyme probes reported to date. 10 refs., 7 figs.

  5. Induction of mixed-function oxidase activity in mouse lymphoid tissues by polycyclic aromatic hydrocarbons

    SciTech Connect

    Griffin, G.D.; Egan, B.Z.; Lee, N.E.; Burtis, C.A.

    1986-01-01

    Polycyclic aromatic hydrocarbon (PAH) exposure can cause mixed-function oxidase (MFO) enzyme induction in certain tissues of various organisms. Measurements of such induction might serve as a useful bioindicator of human exposure to PAHs, provided readily obtainable human tissues can be utilized for such measurements. The authors have investigated the MFO activity in various lymphoid tissues of the C3H mouse as a model system and have studied the effect of systemic PAH treatment on such enzyme activity. An MFO enzyme assay was used to measure the activity of 7-ethoxyresorufin deethylase, an enzyme activity that may be specific for the cytochrome P-448 subset of MFO enzymes (those enzymes that are induced in cells or tissues following PAH administration). Intraperitoneal injection of mice with 180 mg/kg (4.6 mg) benzo(a)pyrene (BaP) or 160 mg/kg (4.0 mg) 3-methylcholanthrene (MC) produced a significant induction in MFO activity in mouse spleen S9 fractions 48 h after the injection. Induction ratios (induced activity/control activity) between 4 and 5 were seen with BaP; MC produced induction ratios of 2.5-3.0. Enzyme activity was not induced in the spleen within 16 h following BaP or MC administration. Other experiments indicated that MFO activity could be induced in thymus cells 48 h after either BaP or MC treatment. Treatment with BaP or MC did produce significant enzyme induction in the liver and lung tissues from the animals both 16 and 48 h after chemical treatment.

  6. Measurement of Self-Inductance.

    ERIC Educational Resources Information Center

    Mak, S. Y.; Tao, P. K.

    1988-01-01

    Discusses four different methods for measuring self-inductance based on the definition of inductance, the alternative definition, phase difference and LC resonance. Provides circuit diagrams and typical oscilloscope traces. (YP)

  7. Enzyme Kinetics in Microgravity

    NASA Astrophysics Data System (ADS)

    Liu, C. C.; Licata, V. J.

    2010-04-01

    The kinetics of some enzymes have been found to be enhanced by the microgravity environment. This is a relatively small effect, but is sufficient to have physiological effects and to impact pharmaceutical therapy in microgravity.

  8. Enzymes in Analytical Chemistry.

    ERIC Educational Resources Information Center

    Fishman, Myer M.

    1980-01-01

    Presents tabular information concerning recent research in the field of enzymes in analytic chemistry, with methods, substrate or reaction catalyzed, assay, comments and references listed. The table refers to 128 references. Also listed are 13 general citations. (CS)

  9. RNA as an Enzyme.

    ERIC Educational Resources Information Center

    Cech, Thomas R.

    1986-01-01

    Reviews current findings that explain RNA's function as an enzyme in addition to being an informational molecule. Highlights recent research efforts and notes changes in the information base on RNA activity. Includes models and diagrams of RNA activity. (ML)

  10. Inductive Reasoning: A Training Approach

    ERIC Educational Resources Information Center

    Klauer, Karl Josef; Phye, Gary D.

    2008-01-01

    Researchers have examined inductive reasoning to identify different cognitive processes when participants deal with inductive problems. This article presents a prescriptive theory of inductive reasoning that identifies cognitive processing using a procedural strategy for making comparisons. It is hypothesized that training in the use of the…

  11. Overproduction of ligninolytic enzymes

    DOEpatents

    Elisashvili, Vladimir; Kachlishvili, Eva; Torok, Tamas

    2014-06-17

    Methods, compositions, and systems for overproducing ligninolytic enzymes from the basidiomycetous fungus are described herein. As described, the method can include incubating a fungal strain of Cerrena unicolor IBB 303 in a fermentation system having growth medium which includes lignocellulosic material and then cultivating the fungal strain in the fermentation system under conditions wherein the fungus expresses the ligninolytic enzymes. In some cases, the lignocellulosic material is mandarin peel, ethanol production residue, walnut pericarp, wheat bran, wheat straw, or banana peel.

  12. Inductive Position Sensor

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Simmons, Stephen M. (Inventor)

    2015-01-01

    An inductive position sensor uses three independent inductors inductively coupled by a common medium such as air. First and second inductors are separated by a fixed distance with the first inductor's axial core and second inductor's axial core maintained parallel to one another. A third inductor is disposed between the first and second inductors with the third inductor's axial core being maintained parallel to those of the first and second inductors. The combination of the first and second inductors are configured for relative movement with the third inductor's axial core remaining parallel to those of the first and second inductors as distance changes from the third inductor to each of the first inductor and second inductor. An oscillating current can be supplied to at least one of the three inductors, while voltage induced in at least one of the three inductors not supplied with the oscillating current is measured.

  13. Induction plasma tube

    DOEpatents

    Hull, D.E.

    1982-07-02

    An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

  14. Induction plasma tube

    DOEpatents

    Hull, Donald E.

    1984-01-01

    An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

  15. Induction motor control

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly utilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilizes induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  16. Induction motor control

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  17. Induction plasma tube

    SciTech Connect

    Hull, D.E.

    1984-02-14

    An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

  18. Induction motor control

    NASA Astrophysics Data System (ADS)

    Hansen, Irving G.

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  19. Inductively commutated coilguns

    SciTech Connect

    Mongeau, P.P. )

    1991-01-01

    In this paper the concept and relevance of power factor is presented in regards to high performance launchers. As the scale of launchers grows and as efforts to improve efficiency continue power factor considerations will become crucial in engineering design and ultimate launcher performance limits. The use of motion induced commutation to improve the power factor are discussed. Various approaches to inductive commutation are presented, including: the brush-commutated 9 MJ Coilgun, the solid state-switched coilgun and the quenchgun.

  20. Inductively commutated coilguns

    NASA Astrophysics Data System (ADS)

    Mongeau, Peter P.

    1991-01-01

    The concept and relevance of power factor is presented in the context of high-performance launchers. As the scale of launchers grows and efforts to improve efficiency continue, power factor considerations will become crucial in engineering design and ultimate launcher performance limits. The use of motion-induced commutation to improve the power factor are discussed. Various approaches to inductive commutation are presented, including the brush-commutated 9-MJ coilgun, the solid state-switched coilgun, and the quenchgun.

  1. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  2. Tryptophan-Catabolizing Enzymes – Party of Three

    PubMed Central

    Ball, Helen J.; Jusof, Felicita F.; Bakmiwewa, Supun M.; Hunt, Nicholas H.; Yuasa, Hajime J.

    2014-01-01

    Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) are tryptophan-degrading enzymes that have independently evolved to catalyze the first step in tryptophan catabolism via the kynurenine pathway (KP). The depletion of tryptophan and formation of KP metabolites modulates the activity of the mammalian immune, reproductive, and central nervous systems. IDO and TDO enzymes can have overlapping or distinct functions depending on their expression patterns. The expression of TDO and IDO enzymes in mammals differs not only by tissue/cellular localization but also by their induction by distinct stimuli. To add to the complexity, these genes also have undergone duplications in some organisms leading to multiple isoforms of IDO or TDO. For example, many vertebrates, including all mammals, have acquired two IDO genes via gene duplication, although the IDO1-like gene has been lost in some lower vertebrate lineages. Gene duplications can allow the homologs to diverge and acquire different properties to the original gene. There is evidence for IDO enzymes having differing enzymatic characteristics, signaling properties, and biological functions. This review analyzes the evolutionary convergence of IDO and TDO enzymes as tryptophan-catabolizing enzymes and the divergent evolution of IDO homologs to generate an enzyme family with diverse characteristics not possessed by TDO enzymes, with an emphasis on the immune system. PMID:25346733

  3. Aminoglycoside Modifying Enzymes

    PubMed Central

    Ramirez, Maria S.; Tolmasky, Marcelo E.

    2010-01-01

    Aminoglycosides have been an essential component of the armamentarium in the treatment of life-threatening infections. Unfortunately, their efficacy has been reduced by the surge and dissemination of resistance. In some cases the levels of resistance reached the point that rendered them virtually useless. Among many known mechanisms of resistance to aminoglycosides, enzymatic modification is the most prevalent in the clinical setting. Aminoglycoside modifying enzymes catalyze the modification at different −OH or −NH2 groups of the 2-deoxystreptamine nucleus or the sugar moieties and can be nucleotidyltranferases, phosphotransferases, or acetyltransferases. The number of aminoglycoside modifying enzymes identified to date as well as the genetic environments where the coding genes are located is impressive and there is virtually no bacteria that is unable to support enzymatic resistance to aminoglycosides. Aside from the development of new aminoglycosides refractory to as many as possible modifying enzymes there are currently two main strategies being pursued to overcome the action of aminoglycoside modifying enzymes. Their successful development would extend the useful life of existing antibiotics that have proven effective in the treatment of infections. These strategies consist of the development of inhibitors of the enzymatic action or of the expression of the modifying enzymes. PMID:20833577

  4. Random-walk enzymes

    NASA Astrophysics Data System (ADS)

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-09-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C →U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

  5. Random-walk enzymes

    PubMed Central

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-01-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C → U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics. PMID:26465508

  6. Low inductance gas switching.

    SciTech Connect

    Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.

    2007-10-01

    The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and

  7. Educational inductive gravimeter

    NASA Astrophysics Data System (ADS)

    Nunn, John

    2014-01-01

    A simple inductive gravimeter constructed from a rigid plastic pipe and insulated copper wire is described. When a magnet is dropped through the vertically mounted pipe it induces small alternating voltages. These small signals are fed to the microphone input of a typical computer and sampled at a typical rate of 44.1 kHz using a custom computer program. Knowing the geometrical dimensions of the gravimeter and calculating the time intervals between peaks of the recorded signal it is possible to calculate the local gravitational acceleration (g). Limitations and improvements are discussed. Instructions are included throughout so that teachers and pupils can replicate the experiment in their own schools.

  8. The ENZYME database in 2000.

    PubMed

    Bairoch, A

    2000-01-01

    The ENZYME database is a repository of information related to the nomenclature of enzymes. In recent years it has became an indispensable resource for the development of metabolic databases. The current version contains information on 3705 enzymes. It is available through the ExPASy WWW server (http://www.expasy.ch/enzyme/ ). PMID:10592255

  9. The ENZYME database in 2000

    PubMed Central

    Bairoch, Amos

    2000-01-01

    The ENZYME database is a repository of information related to the nomenclature of enzymes. In recent years it has became an indispensable resource for the development of metabolic databases. The current version contains information on 3705 enzymes. It is available through the ExPASy WWW server (http://www. expasy.ch/enzyme/ ). PMID:10592255

  10. Induction of the acetamidase of Aspergillus nidulans by acetate metabolism.

    PubMed

    Hynes, M J

    1977-09-01

    Growth tests and enzyme determinations strongly suggest that the acetamidase of Aspergillus nidulans is induced by a product of acetate metabolism rather than the substrate, acetamide. The cis-dominant mutation, amdI9, which is closely linked to amdS, the structural gene for the acetamidase, results in greatly increased sensitivity to induction by acetate metabolism. Propionate, L-threonine, and ethanol also result in acetamidase induction. Mutations in the facA, facB, and facC genes, which lead to low levels of acetyl-coenzyme A synthase, are epistatic to the amdI9 mutation for strong growth on acetamide medium and abolish acetamide and propionamide induction of the acetamidase and isocitrate lyase enzymes. Acetate, L-threonine, and ethanol, however, can induce these enzymes in strains containing facA and facC lesions but not in strains containing a facB lesion. The evidence suggests that acetamidase and isocitrate lyase may be induced by a similar mechanism. PMID:19418

  11. Current methods of labor induction.

    PubMed

    Swamy, Geeta K

    2012-10-01

    In 2009, approximately 23% of all pregnant women in the United States underwent induction of labor, which is more than double the incidence of 9.5% in 1990. The ultimate goal of labor induction is to achieve vaginal delivery by stimulating uterine contractions before the spontaneous onset of labor. Labor induction is clearly indicated when the benefits outweigh the maternal and fetal risks of continued gestation, as well as potential risks associated with the procedure. Many women undergoing labor induction require cervical ripening--a method to facilitate softening, thinning, and dilation of an unfavorable cervix--because it reduces the time to delivery and incidence of failed induction. This article summarizes currently available methods for labor induction and cervical ripening, advantages and disadvantages of various methods, and the safety and effectiveness of each method based on well-conducted clinical trials. PMID:23009967

  12. Induction of Ovulation

    PubMed Central

    Lamb, Emmet J.

    1965-01-01

    Every effort should be made to find the cause of anovulation since specific therapy directed at correction of a specific hormonal deficiency or excess is, of course, much more effective than any empiric treatment. Moreover, some patients with disorders of ovulation may have serious, even fatal, underlying disorders. The use of thyroid or cortisone has been disappointing except in the treatment of an overt deficiency of thyroid or cortisone or an excess of adrenal androgens. Estrogens and progestational agents have not been consistently effective in the induction of ovulation. The use of clomiphene citrate, which apparently stimulates the release of gonadotropins, and the use of purified gonadotropins of human origin have been quite successful in the induction of ovulation in a variety of disorders of ovarian function. Because of real and potential hazards, the use of these new agents should be restricted to women for whom pregnancy is the primary goal or in whom standard methods of therapy have failed. Neither drug has been released by the Food and Drug Administration for routine clinical use. PMID:14336790

  13. Pulsed inductive HF laser

    NASA Astrophysics Data System (ADS)

    Razhev, A. M.; Churkin, D. S.; Kargapol'tsev, E. S.; Demchuk, S. V.

    2016-03-01

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H2 – F2(NF3 or SF66) and He(Ne) – H2 – F2(NF3 or SF6) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%.

  14. Toying with Enzyme Catalysis.

    ERIC Educational Resources Information Center

    Richards, Debbie

    1998-01-01

    Describes a set of manipulatives that are used to establish a secure understanding of the concepts related to the environmental factors that affect the activities of enzymes. Includes a description of the model components and procedures for construction of the model. (DDR)

  15. Photoperiodism and Enzyme Activity

    PubMed Central

    Queiroz, Orlando; Morel, Claudine

    1974-01-01

    Metabolic readjustments after a change from long days to short days appear, in Kalanchoe blossfeldiana, to be achieved through the operation of two main mechanisms: variation in enzyme capacity, and circadian rhythmicity. After a lag time, capacity in phosphoenolpyruvate carboxylase and capacity in aspartate aminotransferase increase exponentially and appear to be allometrically linked during 50 to 60 short days; then a sudden fall takes place in the activity of the former. Malic enzyme and alanine aminotransferase behave differently. Thus, the operation of the two sections of the pathway (before and after the malate step) give rise to a continuously changing functional compartmentation in the pathway. Circadian rhythmicity, on the other hand, produces time compartmentation through phase shifts and variation in amplitude, independently for each enzyme. These characteristics suggest that the operation of a so-called biological clock would be involved. We propose the hypothesis that feedback regulation would be more accurate and efficient when applied to an already oscillating, clock-controlled enzyme system. PMID:16658749

  16. Computational enzyme design

    NASA Astrophysics Data System (ADS)

    Bolon, Daniel N.

    2002-08-01

    The long-term objective of computational enzyme design is the ability to generate efficient protein catalysts for any chemical reaction. This thesis develops and experimentally validates a general computational approach for the design of enzymes with novel function. In order to include catalytic mechanism in protein design, a high-energy state (HES) rotamer (side chain representation) was constructed. In this rotamer, substrate atoms are in a HES. In addition, at least one amino acid side chain is positioned to interact favorably with substrate atoms in their HES and facilitate the reaction. Including an amino acid side chain in the HES rotamer automatically positions substrate relative to a protein scaffold and allows protein design algorithms to search for sequences capable of interacting favorably with the substrate. Because chemical similarity exists between the transition state and the high-energy state, optimizing the protein sequence to interact favorably with the HES rotamer should lead to transition state stabilization. In addition, the HES rotamer model focuses the subsequent computational active site design on a relevant phase space where an amino acid is capable of interacting in a catalytically active geometry with substrate. Using a HES rotamer model of the histidine mediated nucleophilic hydrolysis of p-nitrophenyl acetate, the catalytically inert 108 residue E. coli thioredoxin as a scaffold, and the ORBIT protein design software to compute sequences, an active site scan identified two promising active site designs. Experimentally, both candidate ?protozymes? demonstrated catalytic activity significantly above background. In addition, the rate enhancement of one of these ?protozymes? was the same order of magnitude as the first catalytic antibodies. Because polar groups are frequently buried at enzyme-substrate interfaces, improved modeling of buried polar interactions may benefit enzyme design. By studying native protein structures, rules have been

  17. Monitoring enzyme kinetic behavior of enzyme-quantum dot bioconjugates

    NASA Astrophysics Data System (ADS)

    Claussen, Jonathan C.; Walper, Scott A.; Susumu, Kimihiro; Ancona, Mario G.; Medintz, Igor L.

    2014-05-01

    Luminescent semiconductor nanocrystals or quantum dots (QDs) hold tremendous promise for in vivo biosensing, cellular imaging, theranostics, and smart molecular sensing probes due to their small size and favorable photonic properties such as resistance to photobleaching, size-tunable PL, and large effective Stokes shifts. Herein, we demonstrate how QD-based bioconjugates can be used to enhance enzyme kinetics. Enzyme-substrate kinetics are analyzed for solutions containing both alkaline phosphatase enzymes and QDs with enzyme-to- QD molar ratios of 2, 12, and 24 as well as for a solution containing the same concentration of enzymes but without QDs. The enzyme kinetic paramters Vmax, KM, and Kcat/KM are extracted from the enzyme progress curves via the Lineweaver-Burk plot. Results demonstrate an approximate increase in enzyme efficiency of 5 - 8% for enzymes immobilized on the QD versus free in solution without QD immobilization.

  18. Pulse magnetic-induction regulator

    SciTech Connect

    Vainman, B.N.; Kuprin, A.P.

    1986-04-01

    To create magnetic fields with inductions of ca 4 T, the current in the electromagnet windings must reach tens of amperes, with a power consumptin of several kilowatts. This paper describes a variable pulse regulator of magnetic induction to 4 T in the gap of an electromagnet. The long-term relative magnetic-induction instability is ca 10/sup -4/ V/sup -1/. The low power dissipated by the switch allows natural air cooling to be used.

  19. Production of a new non-specific nuclease from Yersinia enterocolitica subsp. palearctica: optimization of induction conditions using response surface methodology

    PubMed Central

    Fang, Xiu-Juan; Tang, Zhen-Xing; Li, Zhen-Hua; Zhang, Zhi-Liang; Shi, Lu-E

    2014-01-01

    A new non-specific nuclease from Yersinia enterocolitica subsp. palearctica (Y. NSN) was expressed in Escherichia coli (E. coli) BL 21 StarTM (DE3)plysS. Induction conditions, including isopropyl-β-D-thiogalactoside (IPTG) concentration, cell density (OD600), induction time and induction temperature, were optimized using response surface methodology. Statistical analysis of the results revealed that induction temperature and all the quadratic terms of variables had significant effects on enzyme activity of Y. NSN. The optimal induction conditions were as follows: 1.5 mmol/L IPTG, OD600 of 0.80, induction time of 20.5 h, and induction temperature of 32 °C. Under the optimized conditions, the highest enzyme activity could be obtained. PMID:26019543

  20. Phanerochaete flavido-alba Laccase Induction and Modification of Manganese Peroxidase Isoenzyme Pattern in Decolorized Olive Oil Mill Wastewaters

    PubMed Central

    Pérez, J.; de la Rubia, T.; Hamman, O. Ben; Martínez, J.

    1998-01-01

    Lignin-degrading enzymes were partially purified from supernatant solutions obtained from Phanerochaete flavido-alba-decolorized olive oil mill wastewaters (OMW). The dominant enzymes, manganese peroxidases, exhibited different isoform patterns in decolorized OMW-containing cultures than in residue-free samples. Laccase induction was also detected in OMW-containing cultures but not in control cultures. PMID:9647858

  1. Comprehensive Teacher Induction: Linking Teacher Induction to Theory

    ERIC Educational Resources Information Center

    Keilwitz, Heather A.

    2014-01-01

    Teacher retention is a wide concern in education and in response school districts throughout the United States are developing more comprehensive teacher induction programs. Components of teacher induction programs that have assisted with successful teacher development include release time for teacher observation, assignment of a knowledgeable…

  2. Induction Linac Pulsers

    SciTech Connect

    Faltens, Andris

    2011-01-07

    The pulsers used in most of the induction linacs evolved from the very large body of work that was done in the U.S. and Great Britain during the development of the pulsed magnetron for radar. The radar modulators started at {approx}100 kW and reached >10 MW by 1945. A typical pulse length was 1 {mu}s at a repetition rate of 1,000 pps. A very comprehensive account of the modulator development is Pulse Generators by Lebacqz and Glasoe, one of the Radiation Laboratory Series. There are many permutations of possible modulators, two of the choices being tube type and line type. In earlier notes I wrote that technically the vacuum tube pulser met all of our induction linac needs, in the sense that a number of tubes, in series and parallel if required, could produce our pulses, regulate their voltage, be useable in feed-forward correctors, and provide a low source impedance. At a lower speed, an FET array is similar, and we have obtained and tested a large array capable of >10 MW switching. A modulator with an electronically controlled output only needs a capacitor for energy storage and in a switched mode can transfer the energy from the capacitor to the load at high efficiency. Driving a full size Astron induction core and a simulated resistive 'beam load' we achieved >50% efficiency. These electronically controlled output pulses can produce the pulses we desire but are not used because of their high cost. The second choice, the line type pulser, visually comprises a closing switch and a distributed or a lumped element transmission line. The typical switch cannot open or stop conducting after the desired pulse has been produced, and consequently all of the initially stored energy is dissipated. This approximately halves the efficiency, and the original cost estimating program LIACEP used this factor of two, even though our circuits are usually worse, and even though our inveterate optimists often omit it. The 'missing' energy is that which is reflected back into the

  3. Inductive System Health Monitoring

    NASA Technical Reports Server (NTRS)

    Iverson, David L.

    2004-01-01

    The Inductive Monitoring System (IMS) software was developed to provide a technique to automatically produce health monitoring knowledge bases for systems that are either difficult to model (simulate) with a computer or which require computer models that are too complex to use for real time monitoring. IMS uses nominal data sets collected either directly from the system or from simulations to build a knowledge base that can be used to detect anomalous behavior in the system. Machine learning and data mining techniques are used to characterize typical system behavior by extracting general classes of nominal data from archived data sets. IMS is able to monitor the system by comparing real time operational data with these classes. We present a description of learning and monitoring method used by IMS and summarize some recent IMS results.

  4. Inductive Position Sensor

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Simmons, Stephen M. (Inventor)

    2015-01-01

    An inductive position sensor uses three parallel inductors, each of which has an axial core that is an independent magnetic structure. A first support couples first and second inductors and separate them by a fixed distance. A second support coupled to a third inductor disposed between the first and second inductors. The first support and second support are configured for relative movement as distance changes from the third inductor to each of the first and second inductors. An oscillating current is supplied to the first and second inductors. A device measures a phase component of a source voltage generating the oscillating current and a phase component of voltage induced in the third inductor when the oscillating current is supplied to the first and second inductors such that the phase component of the voltage induced overlaps the phase component of the source voltage.

  5. Kinetic inductance magnetometer

    NASA Astrophysics Data System (ADS)

    Luomahaara, Juho; Vesterinen, Visa; Grönberg, Leif; Hassel, Juha

    2014-09-01

    Sensing ultra-low magnetic fields has various applications in the fields of science, medicine and industry. There is a growing need for a sensor that can be operated in ambient environments where magnetic shielding is limited or magnetic field manipulation is involved. To this end, here we demonstrate a new magnetometer with high sensitivity and wide dynamic range. The device is based on the current nonlinearity of superconducting material stemming from kinetic inductance. A further benefit of our approach is of extreme simplicity: the device is fabricated from a single layer of niobium nitride. Moreover, radio frequency multiplexing techniques can be applied, enabling the simultaneous readout of multiple sensors, for example, in biomagnetic measurements requiring data from large sensor arrays.

  6. Borehole induction coil transmitter

    DOEpatents

    Holladay, Gale; Wilt, Michael J.

    2002-01-01

    A borehole induction coil transmitter which is a part of a cross-borehole electromagnetic field system that is used for underground imaging applications. The transmitter consists of four major parts: 1) a wound ferrite or mu-metal core, 2) an array of tuning capacitors, 3) a current driver circuit board, and 4) a flux monitor. The core is wound with several hundred turns of wire and connected in series with the capacitor array, to produce a tuned coil. This tuned coil uses internal circuitry to generate sinusoidal signals that are transmitted through the earth to a receiver coil in another borehole. The transmitter can operate at frequencies from 1-200 kHz and supplies sufficient power to permit the field system to operate in boreholes separated by up to 400 meters.

  7. Tolerance Induction in Liver.

    PubMed

    Karimi, M H; Geramizadeh, B; Malek-Hosseini, S A

    2015-01-01

    Liver is an exclusive anatomical and immunological organ that displays a considerable tolerance effect. Liver allograft acceptance is shown to occur spontaneously within different species. Although in human transplant patients tolerance is rarely seen, the severity level and cellular mechanisms of transplant rejection vary. Non-paranchymal liver cells, including Kupffer cells, liver sinusoidal endothelial cells, hepatic stellate cells, and resident dendritic cells may participate in liver tolerogenicity. The mentioned cells secret anti-inflammatory cytokines such as TGF-β and IL-10 and express negative co-stimulatory molecules like PD-L1 to mediate immunosuppression. Other mechanisms such as microchimerism, soluble major histocompatibility complex and regulatory T cells may take part in tolerance induction. Understanding the mechanisms involved in liver transplant rejection/tolerance helps us to improve therapeutic options to induce hepatic tolerance. PMID:26082828

  8. Quorum quenching enzymes.

    PubMed

    Fetzner, Susanne

    2015-05-10

    Bacteria use cell-to-cell communication systems based on chemical signal molecules to coordinate their behavior within the population. These quorum sensing systems are potential targets for antivirulence therapies, because many bacterial pathogens control the expression of virulence factors via quorum sensing networks. Since biofilm maturation is also usually influenced by quorum sensing, quenching these systems may contribute to combat biofouling. One possibility to interfere with quorum sensing is signal inactivation by enzymatic degradation or modification. Such quorum quenching enzymes are wide-spread in the bacterial world and have also been found in eukaryotes. Lactonases and acylases that hydrolyze N-acyl homoserine lactone (AHL) signaling molecules have been investigated most intensively, however, different oxidoreductases active toward AHLs or 2-alkyl-4(1H)-quinolone signals as well as other signal-converting enzymes have been described. Several approaches have been assessed which aim at alleviating virulence, or biofilm formation, by reducing the signal concentration in the bacterial environment. These involve the application or stimulation of signal-degrading bacteria as biocontrol agents in the protection of crop plants against soft-rot disease, the use of signal-degrading bacteria as probiotics in aquaculture, and the immobilization or entrapment of quorum quenching enzymes or bacteria to control biofouling in membrane bioreactors. While most approaches to use quorum quenching as antivirulence strategy are still in the research phase, the growing number of organisms and enzymes known to interfere with quorum sensing opens up new perspectives for the development of innovative antibacterial strategies. PMID:25220028

  9. INDUCTION AND REPRESSION OF l-ARABINOSE ISOMERASE IN PEDIOCOCCUS PENTOSACEUS1

    PubMed Central

    Dobrogosz, Walter J.; DeMoss, Ralph D.

    1963-01-01

    Dobrogosz, Walter J. (University of Illinois, Urbana) and Ralph D. DeMoss. Induction and repression of l-arabinose isomerase in Pediococcus pentosaceus. J. Bacteriol. 85:1350–1355. 1963.—The inducible l-arabinose isomerase of Pediococcus pentosaceus can be rapidly and conveniently measured in whole-cell preparations by use of a standard colorimetric procedure originally developed for studies with cell-free enzyme preparations. The enzyme is measured by its ability to catalyze the isomerization of l-arabinose to l-ribulose. Whole cells suspended in a suitable buffer and pretreated with toluene were shown to exhibit this isomerase activity at a level comparable with that observed in cell-free enzyme preparations. Conditions for optimal induction of l-arabinose isomerase are described. In addition, it was determined that the formation of this enzyme is subject to repression by glucose, i.e., via catabolite repression. PMID:14047229

  10. From Inductive Reasoning to Proof

    ERIC Educational Resources Information Center

    Yopp, David A.

    2009-01-01

    Mathematical proof is an expression of deductive reasoning (drawing conclusions from previous assertions). However, it is often inductive reasoning (conclusions drawn on the basis of examples) that helps learners form their deductive arguments, or proof. In addition, not all inductive arguments generate more formal arguments. This article draws a…

  11. Sampling Assumptions in Inductive Generalization

    ERIC Educational Resources Information Center

    Navarro, Daniel J.; Dry, Matthew J.; Lee, Michael D.

    2012-01-01

    Inductive generalization, where people go beyond the data provided, is a basic cognitive capability, and it underpins theoretical accounts of learning, categorization, and decision making. To complete the inductive leap needed for generalization, people must make a key "sampling" assumption about how the available data were generated. Previous…

  12. A Student Teamwork Induction Protocol

    ERIC Educational Resources Information Center

    Kamau, Caroline; Spong, Abigail

    2015-01-01

    Faulty group processes have harmful effects on performance but there is little research about intervention protocols to pre-empt them in higher education. This naturalistic experiment compared a control cohort with an inducted cohort. The inducted cohort attended a workshop, consultations, elected a leader and used tools (a group log and group…

  13. Complex Drug Interactions of HIV Protease Inhibitors 2: In Vivo Induction and In Vitro to In Vivo Correlation of Induction of Cytochrome P450 1A2, 2B6, and 2C9 by Ritonavir or Nelfinavir

    PubMed Central

    Kirby, Brian J.; Collier, Ann C.; Kharasch, Evan D.; Dixit, Vaishali; Desai, Pankaj; Whittington, Dale; Thummel, Kenneth E.

    2011-01-01

    Drug-drug interactions (DDIs) with the HIV protease inhibitors (PIs) are complex, paradoxical (e.g., ritonavir/alprazolam), and involve multiple mechanisms. As part of a larger study to better understand these DDIs and to devise a framework for in vitro to in vivo prediction of these DDIs, we determined the inductive effect of ∼2 weeks of administration of two prototypic PIs, nelfinavir (NFV), ritonavir (RTV), and rifampin (RIF; induction positive control) on the cytochrome P450 enzymes CYP1A2, CYP2B6, CYP2C9, and CYP2D6 and the inductive or inductive plus inhibitory effect of NFV, RTV, or RIF on CYP3A and P-glycoprotein in healthy human volunteers. Statistically significant induction of CYP1A2 (2.1-, 2.9-, and 2.2-fold), CYP2B6 (1.8-, 2.4-, and 4-fold), and CYP2C9 (1.3-, 1.8-, and 2.6-fold) was observed after NFV, RTV, or RIF treatment, respectively (as expected, CYP2D6 was not induced). Moreover, we accurately predicted the in vivo induction of these enzymes by quantifying their induction by the PIs in human hepatocytes and by using RIF as an in vitro to in vivo scalar. On the basis of the modest in vivo induction of CYP1A2, CYP2B6, or CYP2C9, the in vivo paradoxical DDIs with the PIs are likely explained by mechanisms other than induction of these enzymes such as induction of other metabolic enzymes, transporters, or both. PMID:21930825

  14. Enzyme linked immunoassay with stabilized polymer saccharide enzyme conjugates

    DOEpatents

    Callstrom, Matthew R.; Bednarski, Mark D.; Gruber, Patrick R.

    1997-01-01

    An improvement in enzyme linked immunoassays is disclosed wherein the enzyme is in the form of a water soluble polymer saccharide conjugate which is stable in hostile environments. The conjugate comprises the enzyme which is linked to the polymer at multiple points through saccharide linker groups.

  15. Enzyme linked immunoassay with stabilized polymer saccharide enzyme conjugates

    DOEpatents

    Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.

    1997-11-25

    An improvement in enzyme linked immunoassays is disclosed wherein the enzyme is in the form of a water soluble polymer saccharide conjugate which is stable in hostile environments. The conjugate comprises the enzyme which is linked to the polymer at multiple points through saccharide linker groups. 19 figs.

  16. Enzyme Molar Fractions: A Powerful Tool for Understanding Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Serra, Juan L.; And Others

    1986-01-01

    Deduces the relationship between reduced velocity and molar fractions for productive enzyme complexes; obtains the mathematical expression of molar fractions for an enzyme with two specific binding sites per molecule; and proposes a useful plot to follow the dependence of enzyme molar fractions with the concentration of one of its ligands. (JN)

  17. Robust enzyme-silica composites made from enzyme nanocapsules.

    PubMed

    Li, Jie; Jin, Xin; Liu, Yang; Li, Fan; Zhang, Linlin; Zhu, Xianyuan; Lu, Yunfeng

    2015-06-14

    Novel enzyme composites are synthesized first by in situ polymerization around enzymes and a subsequent sol-gel process. Both the polymer shell and the silica shell with desired functional moieties provide not only great enzyme protection but also a favorable microenvironment, resulting in significantly enhanced activity and stability. PMID:25971337

  18. Misoprostol for induction of labor.

    PubMed

    Stephenson, Megan L; Wing, Deborah A

    2015-10-01

    Labor-induction rates have increased considerably in the United States as well as around the world. With up to half of all induced labors requiring cervical ripening, prostaglandins have been utilized to increase induction success and achieve vaginal delivery. Misoprostol, a synthetic prostaglandin E1 analog has the ability to mimic the changes of spontaneous labor and has been used off label for over 30 years as a labor-induction agent. In the following article, cervical ripening and induction of labor with misoprostol will be discussed. The risks and benefits of misoprostol for ripening and induction and routes of administration will be reviewed, as well as future directions and new developments for its use. PMID:26601733

  19. Induction of models under uncertainty

    NASA Technical Reports Server (NTRS)

    Cheeseman, Peter

    1986-01-01

    This paper outlines a procedure for performing induction under uncertainty. This procedure uses a probabilistic representation and uses Bayes' theorem to decide between alternative hypotheses (theories). This procedure is illustrated by a robot with no prior world experience performing induction on data it has gathered about the world. The particular inductive problem is the formation of class descriptions both for the tutored and untutored cases. The resulting class definitions are inherently probabilistic and so do not have any sharply defined membership criterion. This robot example raises some fundamental problems about induction; particularly, it is shown that inductively formed theories are not the best way to make predictions. Another difficulty is the need to provide prior probabilities for the set of possible theories. The main criterion for such priors is a pragmatic one aimed at keeping the theory structure as simple as possible, while still reflecting any structure discovered in the data.

  20. Inductance due to spin current

    SciTech Connect

    Chen, Wei

    2014-03-21

    The inductance of spintronic devices that transport charge neutral spin currents is discussed. It is known that in a media that contains charge neutral spins, a time-varying electric field induces a spin current. We show that since the spin current itself produces an electric field, this implies existence of inductance and electromotive force when the spin current changes with time. The relations between the electromotive force and the corresponding flux, which is a vector calculated by the cross product of electric field and the trajectory of the device, are clarified. The relativistic origin generally renders an extremely small inductance, which indicates the advantage of spin current in building low inductance devices. The same argument also explains the inductance due to electric dipole current and applies to physical dipoles consist of polarized bound charges.

  1. Sulfite oxidizing enzymes

    PubMed Central

    Feng, Changjian; Tollin, Gordon; Enemark, John H.

    2007-01-01

    Sulfite oxidizing enzymes are essential mononuclear molybdenum (Mo) proteins involved in sulfur metabolism of animals, plants and bacteria. There are three such enzymes presently known: (1) sulfite oxidase (SO) in animals, (2) SO in plants, and (3) sulfite dehydrogenase (SDH) in bacteria. X-ray crystal structures of enzymes from all three sources (chicken SO, Arabidopsis thaliana SO, and Starkeya novella SDH) show nearly identical square pyramidal coordination around the Mo atom, even though the overall structures of the proteins and the presence of additional cofactors vary. This structural information provides a molecular basis for studying the role of specific amino acids in catalysis. Animal SO catalyzes the final step in the degradation of sulfur-containing amino acids and is critical in detoxifying excess sulfite. Human SO deficiency is a fatal genetic disorder that leads to early death, and impaired SO activity is implicated in sulfite neurotoxicity. Animal SO and bacterial SDH contain both Mo and heme domains, whereas plant SO only has the Mo domain. Intraprotein electron transfer (IET) between the Mo and Fe centers in animal SO and bacterial SDH is a key step in the catalysis, which can be studied by laser flash photolysis in the presence of deazariboflavin. IET studies on animal SO and bacterial SDH clearly demonstrate the similarities and differences between these two types of sulfite oxidizing enzymes. Conformational change is involved in the IET of animal SO, in which electrostatic interactions may play a major role in guiding the docking of the heme domain to the Mo domain prior to electron transfer. In contrast, IET measurements for SDH demonstrate that IET occurs directly through the protein medium, which is distinctly different from that in animal SO. Point mutations in human SO can result in significantly impaired IET or no IET, thus rationalizing their fatal effects. The recent developments in our understanding of sulfite oxidizing enzyme

  2. Bridge Inductance of Induction Motor with Closed Rotor Slots

    NASA Astrophysics Data System (ADS)

    Matsushita, Makoto; Ishibashi, Fuminori; Suzuki, Takao; Noda, Shinichi

    Closed rotor slots are widely employed in low-power squirrel-cage induction motors with die-cast aluminum cage rotors. Die-cast aluminum cages with closed rotor slots can be manufactured commercially. They help reduce flux pulsation in air gaps, attenuate acoustic noises, and achieve high efficiency. However, it is difficult to calculate bridge inductance of a closed rotor slot accurately because the main flux passes through the bridge and iron saturation can be achieved depending upon the bar current. In this study, bridge inductance was investigated by using a search coil and by FEM analysis and conventional equations. The bridge flux density and the bridge linkage flux were measured by using 4P-0.75kW motor with closed rotor slots, and the bridge inductance was calculated as a function of rotor bar current. The bridge inductance was also analyzed by FEM, and the results were analytically checked by using the calculated conventional equations. From these analyses, it is seen that the measured values of the bridge inductance are in good agreement with the values calculated by FEM and conventional methods. It is verified that the bridge inductance shows a trend similar to that of the μ-H curve of the rotor steel sheet.

  3. Treating Wastewater With Immobilized Enzymes

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.

    1991-01-01

    Experiments show enzymes are immobilized on supporting materials to make biocatalyst beds for treatment of wastewater. With suitable combination of enzymes, concentrations of various inorganic and organic contaminants, including ammonia and urea, reduced significantly.

  4. In vitro and pharmacophore insights into CYP3A enzymes.

    PubMed

    Ekins, Sean; Stresser, David M; Williams, J Andrew

    2003-04-01

    The cytochrome P450 3A (CYP3A) enzymes have a major role in the metabolism of drugs in humans. Their wide substrate specificity and induction by a vast array of structurally diverse compounds presents the possibility of metabolic drug-drug interactions. Understanding the enzymes themselves is crucial. Over the past decade, this has occurred mostly with in vitro studies, although more recent approaches incorporate computational models to predict CYP inhibition and substrate potential. The three-dimensional displacement, or pharmacophore, of chemical features in space that are derived from inhibition data have produced pharmacophores for CYP3A4, CYP3A5 and CYP3A7, and provide new insights into ligand binding for each enzyme. PMID:12707001

  5. The Catalytic Function of Enzymes.

    ERIC Educational Resources Information Center

    Splittgerber, Allan G.

    1985-01-01

    Discusses: structure of the enzyme molecule; active site; reaction mechanism; transition state; factors affecting enzyme reaction rates, concentration of enzyme; concentration of substrate; product concentration; temperature effects and pH effects; factors causing a lowering of activation energy; proximity and orientation effects; substrate strain…

  6. Interfacial activation-based molecular bioimprinting of lipolytic enzymes.

    PubMed Central

    Mingarro, I; Abad, C; Braco, L

    1995-01-01

    Interfacial activation-based molecular (bio)-imprinting (IAMI) has been developed to rationally improve the performance of lipolytic enzymes in nonaqueous environments. The strategy combinedly exploits (i) the known dramatic enhancement of the protein conformational rigidity in a water-restricted milieu and (ii) the reported conformational changes associated with the activation of these enzymes at lipid-water interfaces, which basically involves an increased substrate accessibility to the active site and/or an induction of a more competent catalytic machinery. Six model enzymes have been assayed in several model reactions in nonaqueous media. The results, rationalized in light of the present biochemical and structural knowledge, show that the IAMI approach represents a straightforward, versatile method to generate manageable, activated (kinetically trapped) forms of lipolytic enzymes, providing under optimal conditions nonaqueous rate enhancements of up to two orders of magnitude. It is also shown that imprintability of lipolytic enzymes depends not only on the nature of the enzyme but also on the "quality" of the interface used as the template. PMID:7724558

  7. Rotational magnetic induction tomography

    NASA Astrophysics Data System (ADS)

    Trakic, Adnan; Eskandarnia, Neda; Keong Li, Bing; Weber, Ewald; Wang, Hua; Crozier, Stuart

    2012-02-01

    In magnetic induction tomography (MIT), an array of excitation coils is typically used to apply time-varying magnetic fields to induce eddy currents in the material to be studied. The magnetic fields from the eddy currents are then detected by an array of sensing coils to form an image of passive electromagnetic properties (i.e. conductivity, permittivity and permeability). Increasing the number of transmitters and receivers can provide a better image quality at the expense of a larger and more expensive MIT system. Instead of increasing the number of coils, this study investigates the possibility of rotating a single transmit-receive coil to image the electrical properties of the sample, by emulating an array of 200 transmit-receive coils by time-division multiplexing. Engineering details on the electromechanical design and development of a rotating MIT system are presented. The experimental results indicate that representative images of conductive samples can be obtained at 5 MHz by rotating a single transmit-receive coil.

  8. Volumetric magnetic induction tomography

    NASA Astrophysics Data System (ADS)

    Wei, H.-Y.; Ma, L.; Soleimani, M.

    2012-05-01

    Magnetic induction tomography (MIT) is a new and emerging type of tomography technique that is able to map the passive electromagnetic properties (in particular conductivity) of an object. Because of its non-invasive feature, it becomes a suitable technique for many industries, such as metal processing and mining. This paper presents a volumetric MIT (VMIT) system based on an existing measurement setup in our 2D system (MIT Mk-I). By increasing the number of sensors in the axial direction, volumetric imaging can be realized and hence can improve the spatial resolution of the reconstructed images. All of the system control, data acquisition and signal demodulation are accomplished by a commercial data acquisition card and the National Instruments graphical programming language. In this paper, both the system architecture and the forward 3D sensitivity model will be presented. The image reconstruction scheme is modified by introducing a 3D sensitivity map to replace the previous 2D sensitivity map used for the MIT Mk-I system. The iterative Landweber technique was implemented as the inverse solver to reconstruct the images. Several laboratory-based experimental results are demonstrated in this paper, with different shapes of imaging objects. The reconstructed images are satisfactory showing for the first time volumetric conductivity reconstruction using a multi-layer MIT system. The results indicate the high-quality image reconstruction using our novel VMIT system for potential use in industrial applications, such as metal flow imaging.

  9. Linear induction pump

    DOEpatents

    Meisner, John W.; Moore, Robert M.; Bienvenue, Louis L.

    1985-03-19

    Electromagnetic linear induction pump for liquid metal which includes a unitary pump duct. The duct comprises two substantially flat parallel spaced-apart wall members, one being located above the other and two parallel opposing side members interconnecting the wall members. Located within the duct are a plurality of web members interconnecting the wall members and extending parallel to the side members whereby the wall members, side members and web members define a plurality of fluid passageways, each of the fluid passageways having substantially the same cross-sectional flow area. Attached to an outer surface of each side member is an electrically conductive end bar for the passage of an induced current therethrough. A multi-phase, electrical stator is located adjacent each of the wall members. The duct, stators, and end bars are enclosed in a housing which is provided with an inlet and outlet in fluid communication with opposite ends of the fluid passageways in the pump duct. In accordance with a preferred embodiment, the inlet and outlet includes a transition means which provides for a transition from a round cross-sectional flow path to a substantially rectangular cross-sectional flow path defined by the pump duct.

  10. Protein Crystal Malic Enzyme

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Malic Enzyme is a target protein for drug design because it is a key protein in the life cycle of intestinal parasites. After 2 years of effort on Earth, investigators were unable to produce any crystals that were of high enough quality and for this reason the structure of this important protein could not be determined. Crystals obtained from one STS-50 were of superior quality allowing the structure to be determined. This is just one example why access to space is so vital for these studies. Principal Investigator is Larry DeLucas.

  11. Induction heat treatment of steel

    SciTech Connect

    Semiatin, S.L.; Stutz, D.E.

    1985-01-01

    This book discusses the induction heating. After reviewing heat treating operations for steel and the principles of the heat treatment of steel, an overview of induction heat treating is provided. Next, consideration is given to equipment and equipment selection, coil design, power requirements and temperature control. A discussion of surface and through hardening of steel is provided, including information on frequency and power selection and quenching apparatus. Tempering is considered, followed by information on control of residual stresses, cracking, temper brittleness and the important metallurgical and hardness differences between induction and furnace treated steel.

  12. Inductional Effects in a Halbach Magnet Motion Above Distributed Inductance

    NASA Astrophysics Data System (ADS)

    Tchatchoua, Yves; Conrow, Ary; Kim, Dong; Morgan, Daniel; Majewski, Walerian; Zafar, Zaeema

    2013-03-01

    We experimented with attempts to levitate a linear (bar) Halbach array of five 1'' Nd magnets above a linear inductive track. Next, in order to achieve a control over the relative velocity, we designed a different experiment. In it a large wheel with circumferentially positioned along its rim inducting coils rotates, while the magnet is suspended directly above the rim of the wheel on a force sensor. Faraday's Law with the Lenz's Rule is responsible for the lifting and drag forces on the magnet; the horizontal drag force is measured by another force sensor. Approximating the magnet's linear relative motion over inductors with a motion along a large circle, we may use formulas derived earlier in the literature for linear inductive levitation. We measured lift and drag forces as functions of relative velocity of the Halbach magnet and the inductive ``track,'' in an approximate agreement with the existing theory. We then vary the inductance and shape of the inductive elements to find the most beneficial choice for the lift/drag ratio at the lowest relative speed.

  13. Anion-π Enzymes

    PubMed Central

    2016-01-01

    In this report, we introduce artificial enzymes that operate with anion-π interactions, an interaction that is essentially new to nature. The possibility to stabilize anionic intermediates and transition states on an π-acidic surface has been recently demonstrated, using the addition of malonate half thioesters to enolate acceptors as a biologically relevant example. The best chiral anion-π catalysts operate with an addition/decarboxylation ratio of 4:1, but without any stereoselectivity. To catalyze this important but intrinsically disfavored reaction stereoselectively, a series of anion-π catalysts was equipped with biotin and screened against a collection of streptavidin mutants. With the best hit, the S112Y mutant, the reaction occurred with 95% ee and complete suppression of the intrinsically favored side product from decarboxylation. This performance of anion-π enzymes rivals, if not exceeds, that of the best conventional organocatalysts. Inhibition of the S112Y mutant by nitrate but not by bulky anions supports that contributions from anion-π interactions exist and matter, also within proteins. In agreement with docking results, K121 is shown to be essential, presumably to lower the pKa of the tertiary amine catalyst to operate at the optimum pH around 3, that is below the pKa of the substrate. Most importantly, increasing enantioselectivity with different mutants always coincides with increasing rates and conversion, i.e., selective transition-state stabilization. PMID:27413782

  14. Anion-π Enzymes.

    PubMed

    Cotelle, Yoann; Lebrun, Vincent; Sakai, Naomi; Ward, Thomas R; Matile, Stefan

    2016-06-22

    In this report, we introduce artificial enzymes that operate with anion-π interactions, an interaction that is essentially new to nature. The possibility to stabilize anionic intermediates and transition states on an π-acidic surface has been recently demonstrated, using the addition of malonate half thioesters to enolate acceptors as a biologically relevant example. The best chiral anion-π catalysts operate with an addition/decarboxylation ratio of 4:1, but without any stereoselectivity. To catalyze this important but intrinsically disfavored reaction stereoselectively, a series of anion-π catalysts was equipped with biotin and screened against a collection of streptavidin mutants. With the best hit, the S112Y mutant, the reaction occurred with 95% ee and complete suppression of the intrinsically favored side product from decarboxylation. This performance of anion-π enzymes rivals, if not exceeds, that of the best conventional organocatalysts. Inhibition of the S112Y mutant by nitrate but not by bulky anions supports that contributions from anion-π interactions exist and matter, also within proteins. In agreement with docking results, K121 is shown to be essential, presumably to lower the pK a of the tertiary amine catalyst to operate at the optimum pH around 3, that is below the pK a of the substrate. Most importantly, increasing enantioselectivity with different mutants always coincides with increasing rates and conversion, i.e., selective transition-state stabilization. PMID:27413782

  15. Characterising Complex Enzyme Reaction Data.

    PubMed

    Dönertaş, Handan Melike; Martínez Cuesta, Sergio; Rahman, Syed Asad; Thornton, Janet M

    2016-01-01

    The relationship between enzyme-catalysed reactions and the Enzyme Commission (EC) number, the widely accepted classification scheme used to characterise enzyme activity, is complex and with the rapid increase in our knowledge of the reactions catalysed by enzymes needs revisiting. We present a manual and computational analysis to investigate this complexity and found that almost one-third of all known EC numbers are linked to more than one reaction in the secondary reaction databases (e.g., KEGG). Although this complexity is often resolved by defining generic, alternative and partial reactions, we have also found individual EC numbers with more than one reaction catalysing different types of bond changes. This analysis adds a new dimension to our understanding of enzyme function and might be useful for the accurate annotation of the function of enzymes and to study the changes in enzyme function during evolution. PMID:26840640

  16. Characterising Complex Enzyme Reaction Data

    PubMed Central

    Rahman, Syed Asad; Thornton, Janet M.

    2016-01-01

    The relationship between enzyme-catalysed reactions and the Enzyme Commission (EC) number, the widely accepted classification scheme used to characterise enzyme activity, is complex and with the rapid increase in our knowledge of the reactions catalysed by enzymes needs revisiting. We present a manual and computational analysis to investigate this complexity and found that almost one-third of all known EC numbers are linked to more than one reaction in the secondary reaction databases (e.g., KEGG). Although this complexity is often resolved by defining generic, alternative and partial reactions, we have also found individual EC numbers with more than one reaction catalysing different types of bond changes. This analysis adds a new dimension to our understanding of enzyme function and might be useful for the accurate annotation of the function of enzymes and to study the changes in enzyme function during evolution. PMID:26840640

  17. Industrial use of immobilized enzymes.

    PubMed

    DiCosimo, Robert; McAuliffe, Joseph; Poulose, Ayrookaran J; Bohlmann, Gregory

    2013-08-01

    Although many methods for enzyme immobilization have been described in patents and publications, relatively few processes employing immobilized enzymes have been successfully commercialized. The cost of most industrial enzymes is often only a minor component in overall process economics, and in these instances, the additional costs associated with enzyme immobilization are often not justified. More commonly the benefit realized from enzyme immobilization relates to the process advantages that an immobilized catalyst offers, for example, enabling continuous production, improved stability and the absence of the biocatalyst in the product stream. The development and attributes of several established and emerging industrial applications for immobilized enzymes, including high-fructose corn syrup production, pectin hydrolysis, debittering of fruit juices, interesterification of food fats and oils, biodiesel production, and carbon dioxide capture are reviewed herein, highlighting factors that define the advantages of enzyme immobilization. PMID:23436023

  18. Adjustable Induction-Heating Coil

    NASA Technical Reports Server (NTRS)

    Ellis, Rod; Bartolotta, Paul

    1990-01-01

    Improved design for induction-heating work coil facilitates optimization of heating in different metal specimens. Three segments adjusted independently to obtain desired distribution of temperature. Reduces time needed to achieve required temperature profiles.

  19. Induction heating coupler and annealer

    NASA Technical Reports Server (NTRS)

    Fox, Robert L. (Inventor); Johnson, Samuel D. (Inventor); Copeland, Carl E. (Inventor); Coultrip, Robert H. (Inventor); Phillips, W. Morris (Inventor); Johnston, David F. (Inventor); Swaim, Robert J. (Inventor); Dinkins, James R. (Inventor)

    1994-01-01

    An induction heating device includes a handle having a hollow interior and two opposite ends, a wrist connected to one end of the handle, a U-shaped pole piece having- two spaced apart ends, a tank circuit including an induction coil wrapped around the pole piece and a capacitor connected to the induction coil, a head connected to the wrist and including a housing for receiving the U-shaped pole piece, the two spaced apart ends of the pole piece extending outwardly beyond the housing, and a power source connected to the tank circuit. When the tank circuit is energized and a susceptor is placed in juxtaposition to the ends of the U-shaped pole piece, the susceptor is heated by induction heating due to a magnetic flux passing between the two ends of the pole piece.

  20. Operating an induction melter apparatus

    DOEpatents

    Roach, Jay A.; Richardson, John G.; Raivo, Brian D.; Soelberg, Nicholas R.

    2006-01-31

    Apparatus and methods of operation are provided for a cold-crucible-induction melter for vitrifying waste wherein a single induction power supply may be used to effect a selected thermal distribution by independently energizing at least two inductors. Also, a bottom drain assembly may be heated by an inductor and may include an electrically resistive heater. The bottom drain assembly may be cooled to solidify molten material passing therethrough to prevent discharge of molten material therefrom. Configurations are provided wherein the induction flux skin depth substantially corresponds with the central longitudinal axis of the crucible. Further, the drain tube may be positioned within the induction flux skin depth in relation to material within the crucible or may be substantially aligned with a direction of flow of molten material within the crucible. An improved head design including four shells forming thermal radiation shields and at least two gas-cooled plenums is also disclosed.

  1. Multipurpose Vacuum Induction Processing System

    NASA Astrophysics Data System (ADS)

    Govindaraju, M.; Kulkarni, Deepak; Balasubramanian, K.

    2012-11-01

    Multipurpose vacuum processing systems are cost effective; occupy less space, multiple functional under one roof and user friendly. A multipurpose vacuum induction system was designed, fabricated and installed in a record time of 6 months time at NFTDC Hyderabad. It was designed to function as a) vacuum induction melting/refining of oxygen free electronic copper/pure metals, b) vacuum induction melting furnace for ferrous materials c) vacuum induction melting for non ferrous materials d) large vacuum heat treatment chamber by resistance heating (by detachable coil and hot zone) e) bottom discharge vacuum induction melting system for non ferrous materials f) Induction heat treatment system and g) directional solidification /investment casting. It contains provision for future capacity addition. The attachments require to manufacture multiple shaped castings and continuous rod casting can be added whenever need arises. Present capacity is decided on the requirement for 10years of development path; presently it has 1.2 ton liquid copper handling capacity. It is equipped with provision for capacity addition up to 2 ton liquid copper handling capacity in future. Provision is made to carry out the capacity addition in easy steps quickly. For easy operational maintenance and troubleshooting, design was made in easily detachable sections. High vacuum system is also is detachable, independent and easily movable which is first of its kind in the country. Detailed design parameters, advantages and development history are presented in this paper.

  2. Simple Laboratory Exercise for Induction of Beta-Mannanase from "Aspergillus niger"

    ERIC Educational Resources Information Center

    Mulimani, V. H.; Naganagouda, K.

    2010-01-01

    This laboratory experiment was designed for Biochemistry, Biotechnology, Microbiology, and Food Technology students of undergraduate and postgraduate courses. The experiment shows the advantages of using agricultural waste, copra mannan as potent inducer of [beta]-mannanase. The students were able to compare the enzyme induction by commercial…

  3. AN INTEGRATED PHARMACOKINETIC AND PHARMACODYNAMIC STUDY OF ARSENITE ACTION 2. HEME OXYGENASE INDUCTION IN MICE

    EPA Science Inventory

    Heme oxygenase (HO) is the rate-limiting enzyme in heme degradation and its activity has a significant impact on intracellular heme pools. Rat studies indicate that HO induction is a sensitive, dose-dependent response to arsenite (AsIII) exposure in both liver and kidney. The o...

  4. INDUCTION OF CYTOCHROME P450 ISOFORMS IN RAT LIVER BY TWO CONAZOLES, TRIADIMEFON AND MYCLOBUTANIL

    EPA Science Inventory

    1. This study was undertaken to examine the inductive effects of two triazole antifungal agents, myclobutanil and triadimefon on the expression of hepatic cytochrome P450 (CYP) genes and on the activities of CYP enzymes in male Sprague-Dawley rats. Rats were dosed by gavage for 1...

  5. Inductive System Monitors Tasks

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Inductive Monitoring System (IMS) software developed at Ames Research Center uses artificial intelligence and data mining techniques to build system-monitoring knowledge bases from archived or simulated sensor data. This information is then used to detect unusual or anomalous behavior that may indicate an impending system failure. Currently helping analyze data from systems that help fly and maintain the space shuttle and the International Space Station (ISS), the IMS has also been employed by data classes are then used to build a monitoring knowledge base. In real time, IMS performs monitoring functions: determining and displaying the degree of deviation from nominal performance. IMS trend analyses can detect conditions that may indicate a failure or required system maintenance. The development of IMS was motivated by the difficulty of producing detailed diagnostic models of some system components due to complexity or unavailability of design information. Successful applications have ranged from real-time monitoring of aircraft engine and control systems to anomaly detection in space shuttle and ISS data. IMS was used on shuttle missions STS-121, STS-115, and STS-116 to search the Wing Leading Edge Impact Detection System (WLEIDS) data for signs of possible damaging impacts during launch. It independently verified findings of the WLEIDS Mission Evaluation Room (MER) analysts and indicated additional points of interest that were subsequently investigated by the MER team. In support of the Exploration Systems Mission Directorate, IMS is being deployed as an anomaly detection tool on ISS mission control consoles in the Johnson Space Center Mission Operations Directorate. IMS has been trained to detect faults in the ISS Control Moment Gyroscope (CMG) systems. In laboratory tests, it has already detected several minor anomalies in real-time CMG data. When tested on archived data, IMS was able to detect precursors of the CMG1 failure nearly 15 hours in advance of

  6. 14 CFR 25.1091 - Air induction.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Air induction. 25.1091 Section 25.1091... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply— (1) The air required by that...

  7. 14 CFR 29.1091 - Air induction.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Air induction. 29.1091 Section 29.1091... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Induction System § 29.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply the air required by that engine...

  8. 14 CFR 25.1091 - Air induction.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Air induction. 25.1091 Section 25.1091... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply— (1) The air required by that...

  9. 14 CFR 29.1091 - Air induction.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Air induction. 29.1091 Section 29.1091... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Induction System § 29.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply the air required by that engine...

  10. 14 CFR 25.1091 - Air induction.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Air induction. 25.1091 Section 25.1091... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply— (1) The air required by that...

  11. 14 CFR 29.1091 - Air induction.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Air induction. 29.1091 Section 29.1091... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Induction System § 29.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply the air required by that engine...

  12. 14 CFR 25.1091 - Air induction.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Air induction. 25.1091 Section 25.1091... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply— (1) The air required by that...

  13. 14 CFR 27.1091 - Air induction.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating...

  14. 14 CFR 27.1091 - Air induction.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating...

  15. 14 CFR 27.1091 - Air induction.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating...

  16. 14 CFR 27.1091 - Air induction.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating...

  17. 14 CFR 29.1091 - Air induction.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Air induction. 29.1091 Section 29.1091... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Induction System § 29.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply the air required by that engine...

  18. 14 CFR 25.1091 - Air induction.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Air induction. 25.1091 Section 25.1091... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply— (1) The air required by that...

  19. 14 CFR 29.1091 - Air induction.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Air induction. 29.1091 Section 29.1091... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Induction System § 29.1091 Air induction. (a) The air induction system for each engine and auxiliary power unit must supply the air required by that engine...

  20. 14 CFR 27.1091 - Air induction.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating...

  1. Enzyme molecules in solitary confinement.

    PubMed

    Liebherr, Raphaela B; Gorris, Hans H

    2014-01-01

    Large arrays of homogeneous microwells each defining a femtoliter volume are a versatile platform for monitoring the substrate turnover of many individual enzyme molecules in parallel. The high degree of parallelization enables the analysis of a statistically representative enzyme population. Enclosing individual enzyme molecules in microwells does not require any surface immobilization step and enables the kinetic investigation of enzymes free in solution. This review describes various microwell array formats and explores their applications for the detection and investigation of single enzyme molecules. The development of new fabrication techniques and sensitive detection methods drives the field of single molecule enzymology. Here, we introduce recent progress in single enzyme molecule analysis in microwell arrays and discuss the challenges and opportunities. PMID:25221867

  2. Induced reactive oxygen species improve enzyme production from Aspergillus niger cultivation.

    PubMed

    Sahoo, Susmita; Rao, K Krishnamurthy; Suraishkumar, G K

    2003-05-01

    Intracellular reactive oxygen species (iROS) induction by HOCl was used as a novel strategy to improve enzyme productivities in Aspergillus niger growing in a bioreactor. With induced iROS, the specific intracellular activities of alpha-amylase, protease, catalase, and glucose oxidase were increased by about 170%, 250%, 320%, and 260%, respectively. The optimum specific iROS level for achieving maximum cell concentration and enzyme production was about 15 mmol g cell-1. The type of iROS inducing the enzyme production was identified to be a derivative of the superoxide radical. PMID:12882014

  3. Carbonic anhydrase enzymes regulate mast cell-mediated inflammation.

    PubMed

    Henry, Everett K; Sy, Chandler B; Inclan-Rico, Juan M; Espinosa, Vanessa; Ghanny, Saleena S; Dwyer, Daniel F; Soteropoulos, Patricia; Rivera, Amariliz; Siracusa, Mark C

    2016-08-22

    Type 2 cytokine responses are necessary for the development of protective immunity to helminth parasites but also cause the inflammation associated with allergies and asthma. Recent studies have found that peripheral hematopoietic progenitor cells contribute to type 2 cytokine-mediated inflammation through their enhanced ability to develop into mast cells. In this study, we show that carbonic anhydrase (Car) enzymes are up-regulated in type 2-associated progenitor cells and demonstrate that Car enzyme inhibition is sufficient to prevent mouse mast cell responses and inflammation after Trichinella spiralis infection or the induction of food allergy-like disease. Further, we used CRISPR/Cas9 technology and illustrate that genetically editing Car1 is sufficient to selectively reduce mast cell development. Finally, we demonstrate that Car enzymes can be targeted to prevent human mast cell development. Collectively, these experiments identify a previously unrecognized role for Car enzymes in regulating mast cell lineage commitment and suggest that Car enzyme inhibitors may possess therapeutic potential that can be used to treat mast cell-mediated inflammation. PMID:27526715

  4. Immobilized Cell and Enzyme Technology

    NASA Astrophysics Data System (ADS)

    Dunnill, P.

    1980-08-01

    The development of immobilized enzyme and cell technology is summarized. Industrial processes for sucrose inversion, penicillin deacylation and glucose isomerization using immobilized enzymes are described. An alternative process for glucose isomerization using immobilized cells, and some other industrial applications of immobilized cells are indicated. Recent developments in immobilized enzyme and cell technology are assessed and the relative merits of the different biochemical catalyst forms are considered.

  5. Enzyme therapeutics for systemic detoxification.

    PubMed

    Liu, Yang; Li, Jie; Lu, Yunfeng

    2015-08-01

    Life relies on numerous biochemical processes working synergistically and correctly. Certain substances disrupt these processes, inducing living organism into an abnormal state termed intoxication. Managing intoxication usually requires interventions, which is referred as detoxification. Decades of development on detoxification reveals the potential of enzymes as ideal therapeutics and antidotes, because their high substrate specificity and catalytic efficiency are essential for clearing intoxicating substances without adverse effects. However, intrinsic shortcomings of enzymes including low stability and high immunogenicity are major hurdles, which could be overcome by delivering enzymes with specially designed nanocarriers. Extensive investigations on protein delivery indicate three types of enzyme-nanocarrier architectures that show more promise than others for systemic detoxification, including liposome-wrapped enzymes, polymer-enzyme conjugates, and polymer-encapsulated enzymes. This review highlights recent advances in these nano-architectures and discusses their applications in systemic detoxifications. Therapeutic potential of various enzymes as well as associated challenges in achieving effective delivery of therapeutic enzymes will also be discussed. PMID:25980935

  6. Negative cooperativity in regulatory enzymes.

    PubMed

    Levitzki, A; Koshland, D E

    1969-04-01

    Negative cooperativity has been observed in CTP synthetase, an allosteric enzyme which contains a regulatory site. Thus, the same enzyme exhibits negative cooperativity for GTP (an effector) and glutamine (a substrate) and positive cooperativity for ATP and UTP (both substrates). In the process of the delineation of these phenomena, diagnostic procedures for negative cooperativity were developed. Application of these procedures to other enzymes indicates that negative cooperativity is a characteristic of many of them. These findings add strong support for the sequential model of subunit interactions which postulates that ligand-induced conformational changes are responsible for regulatory and cooperative phenomena in enzymes. PMID:5256410

  7. Enzyme Mimics: Advances and Applications.

    PubMed

    Kuah, Evelyn; Toh, Seraphina; Yee, Jessica; Ma, Qian; Gao, Zhiqiang

    2016-06-13

    Enzyme mimics or artificial enzymes are a class of catalysts that have been actively pursued for decades and have heralded much interest as potentially viable alternatives to natural enzymes. Aside from having catalytic activities similar to their natural counterparts, enzyme mimics have the desired advantages of tunable structures and catalytic efficiencies, excellent tolerance to experimental conditions, lower cost, and purely synthetic routes to their preparation. Although still in the midst of development, impressive advances have already been made. Enzyme mimics have shown immense potential in the catalysis of a wide range of chemical and biological reactions, the development of chemical and biological sensing and anti-biofouling systems, and the production of pharmaceuticals and clean fuels. This Review concerns the development of various types of enzyme mimics, namely polymeric and dendrimeric, supramolecular, nanoparticulate and proteinic enzyme mimics, with an emphasis on their synthesis, catalytic properties and technical applications. It provides an introduction to enzyme mimics and a comprehensive summary of the advances and current standings of their applications, and seeks to inspire researchers to perfect the design and synthesis of enzyme mimics and to tailor their functionality for a much wider range of applications. PMID:27062126

  8. Enzyme actuated bioresponsive hydrogels

    NASA Astrophysics Data System (ADS)

    Wilson, Andrew Nolan

    Bioresponsive hydrogels are emerging with technological significance in targeted drug delivery, biosensors and regenerative medicine. Conferred with the ability to respond to specific biologically derived stimuli, the design challenge is in effectively linking the conferred biospecificity with an engineered response tailored to the needs of a particular application. Moreover, the fundamental phenomena governing the response must support an appropriate dynamic range and limit of detection. The design of these systems is inherently complicated due to the high interdependency of the governing phenomena that guide the sensing, transduction, and the actuation response of hydrogels. To investigate the dynamics of these materials, model systems may be used which seek to interrogate the system dynamics by uni-variable experimentation and limit confounding phenomena such as: polymer-solute interactions, polymer swelling dynamics and biomolecular reaction-diffusion concerns. To this end, a model system, alpha-chymotrypsin (Cht) (a protease) and a cleavable peptide-chromogen (pro-drug) covalently incorporated into a hydrogel, was investigated to understand the mechanisms of covalent loading and release by enzymatic cleavage in bio-responsive delivery systems. Using EDC and Sulfo-NHS, terminal carboxyl groups of N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, a cleavable chromogen, were conjugated to primary amines of a hydrated poly(HEMA)-based hydrogel. Hydrogel discs were incubated in buffered Cht causing enzyme-mediated cleavage of the peptide and concomitant release of the chromophore for monitoring. To investigate substrate loading and the effects of hydrogel morphology on the system, the concentration of the amino groups (5, 10, 20, and 30 mol%) and the cross-linked density (1, 5, 7, 9 and 12 mol%) were independently varied. Loading-Release Efficiency of the chromogen was shown to exhibit a positive relation to increasing amino groups (AEMA). The release rates demonstrated a

  9. Differential regulation of hepatic enzymes by polycyclic aromatic hydrocarbons and glucocorticoids

    SciTech Connect

    Smith, J.A.; Linder, M.W.; Fernandez, D.; Prough, R.A. )

    1991-03-15

    A putative glucocorticoid (GC) response element has been identified within the first intron of the P450IA1 gene and is apparently necessary for GC-dependent potentiation of polycyclic aromatic hydrocarbon (PAH) induction of P450IA1. In cultured rat hepatocytes, the synthetic GC, dexamethasone (DEX), potentiated PAH induction of both P450IA1 and glutathione S-transferase protein and mRNA. However, DEX caused a small decrease in PAH-dependent induction of NAD(P)H:quinone oxidoreductase (QOR) subunit protein and mRNA in culture. The potentiation of 3-methylcholanthrene (MC) dependent induction of hepatic P450IA1, GST and QOR by low doses of DEX was evaluated in neonatal and adult rats. In neonates, MC induction was potentiated 2-, 1.5-, and 1.4-fold for P450IA1, GST, and QOR activities, respectively, by DEX. However, in adult rats, DEX potentiated MC induction of P450IA1 activity, but repressed MC induction of GST and QOR. Western immunoanalysis and Northern analysis indicated that the changes in these activities were associated with parallel changes in the levels of immunoreactive proteins and mRNA. Glucocorticoids may have an age-dependent influence on the induction of hepatic enzymes by PAH possibly involving other regulatory factors, in addition to Ah and GC receptors.

  10. Flexible heating head for induction heating

    NASA Technical Reports Server (NTRS)

    Fox, Robert L. (Inventor); Johnson, Samuel D. (Inventor); Coultrip, Robert H. (Inventor); Phillips, W. Morris (Inventor)

    1993-01-01

    An induction heating head includes a length of wire having first and second opposite ends and being wound in a flat spiral shape to form an induction coil, a capacitor connected to the first and second ends of the wire, the induction coil and capacitor defining a tank circuit, and a flexible, elastomeric body molded to encase the induction coil. When a susceptor is placed in juxtaposition to the body, and the tank circuit is powered, the susceptor is inductively heated.

  11. 38 CFR 21.282 - Effective date of induction into a rehabilitation program; retroactive induction.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... induction into a rehabilitation program; retroactive induction. 21.282 Section 21.282 Pensions, Bonuses, and... Vocational Rehabilitation and Employment Under 38 U.S.C. Chapter 31 Induction into A Rehabilitation Program § 21.282 Effective date of induction into a rehabilitation program; retroactive induction. (a)...

  12. Rapid electrochemical enzyme assay with enzyme-free calibration.

    PubMed

    Zhang, Maogen; Karra, Sushma; Gorski, Waldemar

    2013-06-18

    The internally calibrated electrochemical continuous enzyme assay (ICECEA, patent pending) was developed for the fast determination of enzyme activity unit (U). The assay depends on the integration of enzyme-free preassay calibration with the actual enzyme assay in one continuous experiment. Such integration resulted in a uniquely shaped amperometric trace that allowed for the selective picomolar determination of redox enzymes. The ICECEA worked because the preassay calibration did not interfere with the enzyme assay allowing both measurements to be performed in succession in the same solution and at the same electrode. The method displayed a good accuracy (relative error, <3%) and precision (relative standard deviation (RSD), <3%) when tested with different working electrodes (carbon nanotubes/chitosan, glassy carbon, platinum) and enzymes (alcohol dehydrogenase, ADH; lactate dehydrogenase, LDH; xanthine oxidase, XOx; glucose oxidase, GOx). The limit of detection for the ADH, LDH, XOx, and GOx was equal to 0.18, 0.14, 0.0031, and 0.11 U L(-1) (or 4.2, 0.72, 89, and 6.0 pM), respectively. The simplicity, reliability, and short analysis time make the ICECEA competitive with the optical enzyme assays currently in use. PMID:23697336

  13. Propionic acidemia in a parturient presenting for induction of labor.

    PubMed

    Schmeck, Alison; Beilin, Yaakov

    2014-11-01

    Propionic acidemia is a congenital disorder of metabolism where the enzyme propionyl-CoA carboxylase is nonfunctional, resulting in an accumulation of propionic acid in the blood. It is important to avoid excess protein intake and a catabolic state to prevent acidemia. Additionally, it may be wise to avoid anesthetic drugs metabolized by propionyl-CoA carboxylase because use of these drugs may lead to acidosis. We present a case of a parturient with propionic acidemia who presented for induction of labor. PMID:25611862

  14. A study of overproduction and enhanced secretion of enzymes. Quarterly report

    SciTech Connect

    Dashek, W.V.

    1993-09-01

    Wood decay within forests, a significant renewable photosynthetic energy resource, is caused primarily by Basidiomycetous fungi, e.g., white rot fungi. These organisms possess the ability to degrade lignin, cellulose and hemicellulose, the main organic polymers of wood. In the case of the white rot fungi, e.g., Coriolus versicolor, the capacity results from the fungus` ability to elaborate extracellular cellulolytic and ligninolytic enzymes. With regard to the latter, at least one of the enzymes, polyphenol oxidase (PPO) appears within a defined growth medium. This proposal focuses on the over-production and enhanced secretion of PPO, cellulase and lignin peroxidase. There are two major sections to the proposal: (1) overproduction of lignocellulolytic enzymes by genetic engineering methodologies and hyper-production and enhanced secretion of these enzymes by biochemical/electro microscopical techniques and (2) the biochemical/electron microscopical method involves substrate induction and the time-dependent addition of respiration and PPO enzymes.

  15. Enzyme catalysis: Evolution made easy

    NASA Astrophysics Data System (ADS)

    Wee, Eugene J. H.; Trau, Matt

    2014-09-01

    Directed evolution is a powerful tool for the development of improved enzyme catalysts. Now, a method that enables an enzyme, its encoding DNA and a fluorescent reaction product to be encapsulated in a gel bead enables the application of directed evolution in an ultra-high-throughput format.

  16. Making the Rate: Enzyme Dynamics

    ERIC Educational Resources Information Center

    Ragsdale, Frances R.

    2004-01-01

    An enzyme exercise to address the problem of students inability to visualize chemical reaction at the molecular level is described. This exercise is designed as a dry lab exercise but can be modified into a classroom activity then can be augmented by a wet lab procedure, thereby providing students with a practical exposure to enzyme function.

  17. Stacked insulator induction accelerator gaps

    SciTech Connect

    Houck, T.I.; Westenskow, G.A.; Kim, J.S.; Eylon, S.; Henestroza, E.; Yu, S.S.; Vanecek, D.

    1997-05-01

    Stacked insulators, with alternating layers of insulating material and conducting film, have been shown to support high surface electrical field stresses. We have investigated the application of the stacked insulator technology to the design of induction accelerator modules for the Relativistic-Klystron Two-Beam Accelerator program. The rf properties of the accelerating gaps using stacked insulators, particularly the impedance at frequencies above the beam pipe cutoff frequency, are investigated. Low impedance is critical for Relativistic-Klystron Two-Beam Accelerator applications where a high current, bunched beam is trsnsported through many accelerating gaps. An induction accelerator module designs using a stacked insulator is presented.

  18. Capacitively-coupled inductive sensor

    DOEpatents

    Ekdahl, Carl A.

    1984-01-01

    A capacitively coupled inductive shunt current sensor which utilizes capacitive coupling between flanges having an annular inductive channel formed therein. A voltage dividing capacitor is connected between the coupling capacitor and ground to provide immediate capacitive division of the output signal so as to provide a high frequency response of the current pulse to be detected. The present invention can be used in any desired outer conductor such as the outer conductor of a coaxial transmission line, the outer conductor of an electron beam transmission line, etc.

  19. Induction linacs and pulsed power

    SciTech Connect

    Caporaso, G.J.

    1995-07-11

    Progress in electronic power conversion technology is making possible a new class of induction linacs that can operate at extremely high repetition rates. Advances in insulator technology, pulse forming line design and switching may also lead to a new type of high current accelerator with accelerating gradients at least an order of magnitude greater than those attainable today. The evolution of the induction accelerator pulsed power system will be discussed along with some details of these emerging technologies which are at the frontiers of accelerator technology.

  20. Inductive storage pulse circuit device

    DOEpatents

    Parsons, William M.; Honig, Emanuel M.

    1984-01-01

    Inductive storage pulse circuit device which is capable of delivering a series of electrical pulses to a load in a sequential manner. Silicon controlled rectifiers as well as spark gap switches can be utilized in accordance with the present invention. A commutation switching array is utilized to produce a reverse current to turn-off the main opening switch. A commutation capacitor produces the reverse current and is initially charged to a predetermined voltage and subsequently charged in alternating directions by the inductive storage current.

  1. Closed inductively coupled plasma cell

    DOEpatents

    Manning, T.J.; Palmer, B.A.; Hof, D.E.

    1990-11-06

    A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies is disclosed. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy. 1 fig.

  2. Closed inductively coupled plasma cell

    DOEpatents

    Manning, Thomas J.; Palmer, Byron A.; Hof, Douglas E.

    1990-01-01

    A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy.

  3. Oxytocin for induction of labor.

    PubMed

    Smith, Jennifer G; Merrill, David C

    2006-09-01

    Oxytocin is the most common pharmacologic agent used for the induction and augmentation of labor. Oxytocin protocols can be divided into high-dose and low-dose protocols depending on the initial dose and the amount and rate of sequential increase in dose. Despite the frequency with which oxytocin in used in clinical practice, there is little consensus regarding which protocol is most appropriate. The purpose of this chapter is to review the most current data concerning recommendations for the use of oxytocin in the induction of labor, including cases of intrauterine fetal demise and vaginal birth after cesarean. PMID:16885666

  4. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.

    1987-05-22

    This invention involved a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide in activators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

  5. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, Joanna S.; MacGregor, Robert R.; Wolf, Alfred P.; Langstrom, Bengt

    1990-01-01

    This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

  6. Engineering Cellulase Enzymes for Bioenergy

    NASA Astrophysics Data System (ADS)

    Atreya, Meera Elizabeth

    Sustainable energy sources, such as biofuels, offer increasingly important alternatives to fossil fuels that contribute less to global climate change. The energy contained within cellulosic biofuels derives from sunlight energy stored in the form of carbon-carbon bonds comprising sugars such as glucose. Second-generation biofuels are produced from lignocellulosic biomass feedstocks, including agricultural waste products and non-food crops like Miscanthus, that contain lignin and the polysaccharides hemicellulose and cellulose. Cellulose is the most abundant biological material on Earth; it is a polymer of glucose and a structural component of plant cell walls. Accessing the sugar is challenging, as the crystalline structure of cellulose resists degradation; biochemical and thermochemical means can be used to depolymerize cellulose. Cellulase enzymes catalyze the biochemical depolymerization of cellulose into glucose. Glucose can be used as a carbon source for growth of a biofuel-producing microorganism. When it converts glucose to a hydrocarbon fuel, this microbe completes the biofuels process of transforming sunlight energy into accessible, chemical energy capable of replacing non-renewable transportation fuels. Due to strong intermolecular interactions between polymer chains, cellulose is significantly more challenging to depolymerize than starch, a more accessible polymer of glucose utilized in first-generation biofuels processes (often derived from corn). While most mammals cannot digest cellulose (dietary fiber), certain fungi and bacteria produce cellulase enzymes capable of hydrolyzing it. These organisms secrete a wide variety of glycoside hydrolase and other classes of enzymes that work in concert. Because cellulase enzymes are slow-acting and expensive to produce, my aim has been to improve the properties of these enzymes as a means to make a cellulosic biofuels process possible that is more efficient and, consequently, more economical than current

  7. Positron emitter labeled enzyme inhibitors

    SciTech Connect

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.; Langstrom, B.

    1990-04-03

    This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

  8. Differential transcriptional responses underlie dietary induction of intestinal carbohydrase activities in house sparrow nestlings.

    PubMed

    Gatica-Sosa, C; Brzęk, P; Chediack, J G; Cid, F D; Karasov, W H; Caviedes-Vidal, E

    2016-04-01

    Many species show diet-induced flexibility of activity of intestinal enzymes; however, molecular and genetic mechanisms responsible for such modulation are less known, particularly in altricial birds. The goal of our study was to test whether a diet-induced increase in activity of intestinal maltase and sucrase in house sparrow nestlings is matched with an increase in maltase-glucoamylase (MG) and sucrase-isomaltase (SI) complex mRNAs respectively. Both enzyme activities were significantly higher in mid-intestine of nestlings fed a medium-starch (MS) diet compared to those fed a starch-free (SF) diet. In contrast to the similar pattern of dietary induction for both enzyme activities, diet MS elevated significantly only the level of MG mRNA, but not SI mRNA. The coordinated increase in activity of maltase and in MG mRNA is consistent with the hypothesis that dietary induction of this enzyme is under transcriptional control. In contrast, the lack of such coordination for changes in activity of sucrase and SI mRNA suggests that upregulation of this enzyme may be achieved by post-translational factor(s). We conclude that genetic mechanisms responsible for diet-induced flexibility of digestive enzymes in birds may differ from that observed in mammals. PMID:26122561

  9. An Adaptive Superintendent Induction Program

    ERIC Educational Resources Information Center

    Brandon, Jim; Donlevy, Kent; Hanna, Paulette; Gereluk, Dianne; Patterson, Peggy; Rhyason, Kath

    2014-01-01

    This study examined a recently established induction program for new superintendents in the Canadian province of Alberta over a three-year period. In keeping with principles of design-based research data were collected from a variety of sources from the 26 new superintendents and their 25 mentors to assess and adjust programming through three…

  10. Experiments with an Induction Cooker

    ERIC Educational Resources Information Center

    Zilavy, Peter

    2009-01-01

    The induction cooker is a common appliance nowadays. How does it work? Why is it not possible to use aluminium utensils with it? What experiments can be carried out with it (at different levels) and not only in physics lessons? Searching for the answers to these and other questions is the purpose of this article. (Contains 5 figures.)

  11. The Inductive Teaching of English.

    ERIC Educational Resources Information Center

    Steinberg, Erwin R.; And Others

    The inductive-method teacher sees himself as part of a process of learning rather than as dispenser of knowledge. He structures classroom situations in which students discover answers and concepts for themselves. He selects material and guides class work, but concentrates on how a student learns, developing a carefully-guided sequence of questions…

  12. Inducting School Leaders. ERIC Digest.

    ERIC Educational Resources Information Center

    Lashway, Larry

    Beginning principals are often overwhelmed by their job. Traditionally, they have been left to fend for themselves. For this reason, schools and districts have been implementing formal induction programs to help the principals during their first year on the job. This digest examines the challenges faced by new administrators and the steps that…

  13. The role of induction therapy

    PubMed Central

    Moremen, Jacob R.; Skopelja, Elaine N.

    2014-01-01

    The incidence of esophageal cancer has been steadily increasing. The 5-year survival of esophageal cancer has minimally improved over the past 30 years. In this article, we review the management of esophageal cancer, focusing on the literature investigating the role of induction chemotherapy and radiation therapy. PMID:24876935

  14. High average power induction accelerators

    SciTech Connect

    Swingle, J.C.

    1985-10-01

    The induction accelerator is discussed with respect to general background and concept, beam transport, scaling, pulse power technology, and the electron beam injector. A discussion of the factors which affect the scaling of the intensity of the beam is given. Limiting factors include collective forces in the beam, virtual cathode formation, surroundings, and beam breakup instability. 24 refs., 11 figs. (WRF)

  15. Teaching the Photoelectric Effect Inductively

    ERIC Educational Resources Information Center

    Sokolowski, Andrzej

    2013-01-01

    Research has shown that students have difficulty understanding the underlying process of the photoelectric effect. Thus, this study sought to utilize an inductively situated lesson for teaching the photoelectric effect, hypothesizing that this type of enquiry would help learners delve deeper into the principles of the phenomenon and provide a…

  16. Identifying a reliable boredom induction.

    PubMed

    Markey, Amanda; Chin, Alycia; Vanepps, Eric M; Loewenstein, George

    2014-08-01

    None of the tasks used to induce boredom have undergone rigorous psychometric validation, which creates potential problems for operational equivalence, comparisons across studies, statistical power, and confounding results. This methodological concern was addressed by testing and comparing the effectiveness of six 5-min. computerized boredom inductions (peg turning, audio, video, signature matching, one-back, and an air traffic control task). The tasks were evaluated using standard criteria for emotion inductions: intensity and discreteness. Intensity, the amount of boredom elicited, was measured using a subset of the Multidimensional State Boredom Scale. Discreteness, the extent to which the task elicited boredom and did not elicit other emotions, was measured using a modification of the Differential Emotion Scale. In both a laboratory setting (Study 1; N = 241) and an online setting with Amazon Mechanical Turk workers (Study 2; N = 416), participants were randomly assigned to one of seven tasks (six boredom tasks or a comparison task, a clip from Planet Earth) before rating their boredom using the MSBS and other emotions using the modified DES. In both studies, each task had significantly higher intensity and discreteness than the comparison task, with moderate to large effect sizes. The peg-turning task outperformed the other tasks in both intensity and discreteness, making it the recommended induction. Identification of reliable and valid boredom inductions and systematic comparison of their relative results should help advance state boredom research. PMID:25153752

  17. Inductively coupled helium plasma torch

    SciTech Connect

    Montaser, Akbar; Chan, Shi-Kit; Van Hoven, Raymond L.

    1989-01-01

    An inductively coupled plasma torch including a base member, a plasma tube and a threaded insert member within the plasma tube for directing the plasma gas in a tangential flow pattern. The design of the torch eliminates the need for a separate coolant gas tube. The torch can be readily assembled and disassembled with a high degree of alignment accuracy.

  18. Electron heating in inductive discharges

    NASA Astrophysics Data System (ADS)

    Hagelaar, Gerjan

    2009-10-01

    Radio-frequency inductive discharges are used to sustain plasma in negative ion sources for neutral beam injection [W. Kraus et al 2002 Rev. Sci. Instrum. 73, 1096] currently under development for the ITER fusion experiment. To accompany the experimental development, a comprehensive numerical model is being developed, describing the main physical principles of these sources self-consistently: inductive coupling and electron heating in the source drivers, magnetised plasma transport in the source body, negative ion extraction across a magnetic filter, low-density neutral flow and depletion by the plasma, chemistry of negative ion creation in the volume and at the surface, etc. In this presentation we discuss the principles and modelling of the inductive electron heating in these sources. In particular, we propose a simple method to describe the anomalous skin effect through a fluid equation for electron momentum including a viscosity term with an effective viscosity coefficient. We also discuss the effects of the static and radio-frequency magnetic fields on the inductive coupling and the consequences for the plasma properties.

  19. Direct-reading inductance meter

    NASA Technical Reports Server (NTRS)

    Kolbly, R. B.

    1977-01-01

    Meter indicates from 30 nH to 3 micro H. Reference inductor of 15 micro H is made by winding 50 turns of Number 26 Formvar wire on Micrometal type 50-2 (or equivalent) core. Circuit eliminates requirement for complex instrument compensation prior to taking coil inductance measurement and thus is as easy to operate as common ohmmeter.

  20. Mathematical Induction: Deductive Logic Perspective

    ERIC Educational Resources Information Center

    Dogan, Hamide

    2016-01-01

    Many studies mentioned the deductive nature of Mathematical Induction (MI) proofs but almost all fell short in explaining its potential role in the formation of the misconceptions reported in the literature. This paper is the first of its kind looking at the misconceptions from the perspective of the abstract of the deductive logic from one's…

  1. Enzyme activity determination using ultrasound

    NASA Astrophysics Data System (ADS)

    Holmes, M. J.; Southworth, T.; Watson, N. G.; Povey, M. J. W.

    2014-04-01

    Here are presented the results of a novel approach to the measurement of enzyme reaction rates in which ultrasound velocity measurement is used. Our results show enzyme activity is observable, in the acoustic context, and that furthermore this offers the potential to estimate the rate of reaction over different substrate concentrations and temperatures. Findings are corroborated with optical microscopy and rheological measurements. Ultrasound velocity measurement can be performed without the need for aliquot extraction and offers an efficient, non-invasive and dynamic method to monitor enzyme activity.

  2. Metabolic regulation via enzyme filamentation

    PubMed Central

    Aughey, Gabriel N.; Liu, Ji-Long

    2016-01-01

    Abstract Determining the mechanisms of enzymatic regulation is central to the study of cellular metabolism. Regulation of enzyme activity via polymerization-mediated strategies has been shown to be widespread, and plays a vital role in mediating cellular homeostasis. In this review, we begin with an overview of the filamentation of CTP synthase, which forms filamentous structures termed cytoophidia. We then highlight other important examples of the phenomenon. Moreover, we discuss recent data relating to the regulation of enzyme activity by compartmentalization into cytoophidia. Finally, we hypothesize potential roles for enzyme filament formation in the regulation of metabolism, development and disease. PMID:27098510

  3. THE REGULATION OF UREA-BIOSYNTHESIS ENZYMES IN VERTEBRATES.

    PubMed

    MORA, J; MARTUSCELLI, J; ORTIZ PINEDA, J; SOBERON, G

    1965-07-01

    1. Carbamoyl phosphate synthetase, ornithine transcarbamoylase, the arginine-synthetase system and arginase were measured in the livers of ammoniotelic, ureotelic and uricotelic animals. The chelonian reptiles, whose nitrogen excretory patterns vary according to the habitat, and the Mexican axolotl, a neotenic species, were also studied. 2. The levels of the activities of the first three enzymes mentioned correlate with the amount of nitrogen excreted as urea. 3. The terrestrial turtle, which excretes mainly uric acid, maintains a high arginase activity but has very low levels of the activities of the other three enzymes. 4. The first three enzymes of the urea cycle vary in the phylogenic scale in a co-ordinated manner, which suggests that they are under the same regulatory mechanism. 5. Urea formation from endogenous arginine in vitro has a low efficiency in the Mexican axolotl. 6. The induction of metamorphosis in the Mexican axolotl by the administration of l-tri-iodothyronine, which causes a shift from ammonio-ureotelism to complete ureotelism, is accompanied by an increase mainly in carbamoyl phosphate synthetase and also by an improvement in the efficiency of hydrolysis of endogenous arginine in vitro to give urea. 7. The results obtained by differential centrifugation of the urea-cycle enzymes in rat and Mexican-axolotl livers are presented. The location requirements for the integration of a metabolic cycle are discussed. PMID:14343146

  4. The regulation of urea-biosynthesis enzymes in vertebrates

    PubMed Central

    Mora, J.; Martuscelli, J.; Ortiz-Pineda, Juana; Soberón, G.

    1965-01-01

    1. Carbamoyl phosphate synthetase, ornithine transcarbamoylase, the arginine-synthetase system and arginase were measured in the livers of ammoniotelic, ureotelic and uricotelic animals. The chelonian reptiles, whose nitrogen excretory patterns vary according to the habitat, and the Mexican axolotl, a neotenic species, were also studied. 2. The levels of the activities of the first three enzymes mentioned correlate with the amount of nitrogen excreted as urea. 3. The terrestrial turtle, which excretes mainly uric acid, maintains a high arginase activity but has very low levels of the activities of the other three enzymes. 4. The first three enzymes of the urea cycle vary in the phylogenic scale in a co-ordinated manner, which suggests that they are under the same regulatory mechanism. 5. Urea formation from endogenous arginine in vitro has a low efficiency in the Mexican axolotl. 6. The induction of metamorphosis in the Mexican axolotl by the administration of l-tri-iodothyronine, which causes a shift from ammonio-ureotelism to complete ureotelism, is accompanied by an increase mainly in carbamoyl phosphate synthetase and also by an improvement in the efficiency of hydrolysis of endogenous arginine in vitro to give urea. 7. The results obtained by differential centrifugation of the urea-cycle enzymes in rat and Mexican-axolotl livers are presented. The location requirements for the integration of a metabolic cycle are discussed. PMID:14343146

  5. Nanoporous gold for enzyme immobilization.

    PubMed

    Stine, Keith J; Jefferson, Kenise; Shulga, Olga V

    2011-01-01

    Nanoporous gold (NPG) is a material of emerging interest for immobilization of biomolecules and -especially enzymes. NPG materials provide a high gold surface area onto which biomolecules can either be directly physisorbed or covalently linked after first modifying the NPG with a self-assembled monolayer. The material can be used as a high surface area electrode and with immobilized enzymes can be used for amperometric detection schemes. NPG can be prepared in a variety of formats from alloys containing less than 50 atomic% gold by dealloying procedures. Related high surface area gold structures have been prepared using templating approaches. Covalent enzyme immobilization can be achieved by first forming a self-assembled monolayer on NPG bearing a terminal reactive functional group followed by conjugation to the enzyme through amide linkages to lysine residues. PMID:20865389

  6. Enzyme immobilisation in permselective microcapsules.

    PubMed

    Pachariyanon, Pavadee; Barth, Ekkehard; Agar, David W

    2011-01-01

    The objective of this investigation was to study the permselective behaviour of calcium alginate membranes, including the modifying effects of silica additives, which were subsequently used as microcapsule shells. Diffusion experiments and HPLC were carried out to ascertain the size-exclusion property of the membranes for a mixed molecular-weight dextran solution. Hollow microcapsules containing the enzyme dextranase were prepared using double concentric nozzles and the encapsulation performance was evaluated based on an analysis of the enzyme reactivity and stability. To improve mass transport within the microcapsules, magnetic nanoparticles were introduced into the liquid core and agitated using an alternating external magnetic field. The modified membranes exhibited better size-exclusion behaviour than the unmodified membranes. The magnetic nanoparticles slightly improved mass transport inside the microcapsule. The encapsulated enzyme yielded nearly 80% of the free enzyme activity and retained about 80% of the initial catalytic activity even after being used for eight reaction cycles. PMID:21736522

  7. Immobilized enzymes affect biofilm formation.

    PubMed

    Cordeiro, Ana L; Hippius, Catharina; Werner, Carsten

    2011-09-01

    The effect of the activity of immobilized enzymes on the initial attachment of pathogenic bacteria commonly associated with nosocomial infections (Pseudomonas aeruginosa and Staphylococcus epidermidis) was investigated. The proteolytic enzymes, subtilisin A and the glycoside hydrolase cellulose, were covalently attached onto poly(ethylene-alt-maleic) anhydride copolymer films. A comparison between active and heat-inactivated surfaces showed that while the activity of immobilized cellulase reduced the attachment of S. epidermidis by 67%, it had no effect on the attachment of P. aeruginosa. Immobilized subtilisin A had opposite effects: the active enzyme had no effect on the attachment of S. epidermidis but reduced the attachment of P. aeruginosa by 44%. The results suggest that different biomolecules are involved in the initial steps of attachment of different bacteria, and that the development of broad-spectrum antifouling enzymatic coatings will need to involve the co-immobilization of enzymes. PMID:21618024

  8. Molybdenum enzymes in higher organisms

    PubMed Central

    Hille, Russ; Nishino, Takeshi; Bittner, Florian

    2010-01-01

    Recent progress in our understanding of the structural and catalytic properties of molybdenum-containing enzymes in eukaryotes is reviewed, along with aspects of the biosynthesis of the cofactor and its insertion into apoprotein. PMID:21516203

  9. PIXE analysis of Zn enzymes

    NASA Astrophysics Data System (ADS)

    Solís, C.; Oliver, A.; Andrade, E.; Ruvalcaba-Sil, J. L.; Romero, I.; Celis, H.

    1999-04-01

    Zinc is a necessary component in the action and structural stability of many enzymes. Some of them are well characterized, but in others, Zn stoichiometry and its association is not known. PIXE has been proven to be a suitable technique for analyzing metallic proteins embedded in electrophoresis gels. In this study, PIXE has been used to investigate the Zn content of enzymes that are known to carry Zn atoms. These include the carbonic anhydrase, an enzyme well characterized by other methods and the cytoplasmic pyrophosphatase of Rhodospirillumrubrum that is known to require Zn to be stable but not how many metal ions are involved or how they are bound to the enzyme. Native proteins have been purified by polyacrylamide gel electrophoresis and direct identification and quantification of Zn in the gel bands was performed with an external proton beam of 3.7 MeV energy.

  10. Labor induction: a review of current methods.

    PubMed

    Ramirez, Mildred M

    2011-06-01

    This article reviews the essential criteria for inductions of labor, weighing both the advantages and disadvantages of labor induction, and the various mechanical and pharmacologic agents available for cervical ripening. At the end of this article, one should be able to counsel women about the potential risks and benefit of labor induction and understand the neonatal consequences of elective induction of labor before 39 weeks of gestation. This article also discusses the different mechanical and pharmacologic agents available for cervical ripening. PMID:21575797

  11. Induction generator-induction motor wind-powered pumping system

    SciTech Connect

    Miranda, M.S.; Lyra, R.O.C.; Silva, S.R.

    1997-12-31

    The energy storage matter plays an important role in wind-electric conversion systems for isolated applications. Having that in mind, two different approaches can be basically considered: either the immediate conversion of the generated electric energy, as in a water pumping system or electric energy storage for later use, as in a battery charging system. Due to some features such as no need of an external reactive power source and, sometimes, a gearbox, permanent-magnet synchronous generators have been broadly used in low rated power isolated systems. Despite that, system performance can be affected when the generator is feeding an inductive load (e.g., an induction motor) under variable-speed-variable-frequency operational conditions. Since there is no effective flux control, motor overload may occur at high wind speeds. Thus, good system performance can be obtained through additional control devices which may increase system cost. Although being rugged and cheap, induction machines always work as a reactive power drain; therefore, they demand an external reactive power source. Considering that, reactive static compensators appear as an attractive alternative to the cost x performance problem. In addition to that, different control strategies can be used so that system performance can be improved.

  12. Enzymes: principles and biotechnological applications

    PubMed Central

    Robinson, Peter K.

    2015-01-01

    Enzymes are biological catalysts (also known as biocatalysts) that speed up biochemical reactions in living organisms, and which can be extracted from cells and then used to catalyse a wide range of commercially important processes. This chapter covers the basic principles of enzymology, such as classification, structure, kinetics and inhibition, and also provides an overview of industrial applications. In addition, techniques for the purification of enzymes are discussed. PMID:26504249

  13. Homogeneous enzyme immunoassay for netilmicin.

    PubMed Central

    Wenk, M; Hemmann, R; Follath, F

    1982-01-01

    A newly developed homogeneous enzyme immunoassay for the determination of netilmicin in serum was evaluated and compared with a radioenzymatic assay. A total of 102 serum samples from patients treated with netilmicin were measured by both methods. This comparison showed an excellent correlation (r = 0.993). The enzyme immunoassay has proved to be precise, accurate, and specific. Because of its rapidity and the ease of performance, this method is a useful alternative to current assays for monitoring serum netilmicin concentrations. PMID:6760807

  14. CYP450 Enzyme-Mediated Metabolism of TCAS and Its Inhibitory and Induced Effects on Metabolized Enzymes in Vitro

    PubMed Central

    Shen, Guolin; Wang, Cheng; Zhou, Lili; Li, Lei; Chen, Huiming; Yu, Wenlian; Li, Haishan

    2015-01-01

    In this study, we investigated the enzymes catalyzing the phaseⅠmetabolism of thiacalixarene (TCAS) based on in vitro system including cDNA-expressed P450 enzymes, human liver microsomes plus inhibitors and monoclonal antibodies. In addition, the inhibitory potential of TCAS on major CYP450 drug metabolizing enzymes (CYP1A2, CYP2C9, CYP2B6, CYP2D6 and CYP3A4) was assessed. The results showed that CYP1A2 and CYP2C9 mediated TCAS hydroxylation. IC50 values for TCAS in rat and human liver microsomes were greater than 50 µM, and it demonstrated a weak inhibition of rat and human CYP450 enzymes. Finally, sandwiched hepatocytes were used to evaluate the induction of CYP1A and CYP3A to define the function of TCAS in vivo. The results showed that incubation of TCAS at different concentrations for 72 h failed to induce CYP1A and CYP3A. However, incubation of the cells with 50 and 100 µM TCAS caused a profound decrease in the activities of CYP1A and CYP3A, which was probably due to cytotoxic effects, suggesting that exposure to TCAS might be a health concern. PMID:26404338

  15. NCTAF/GSU Induction Project. Final Report

    ERIC Educational Resources Information Center

    Black, Linda; Neel, John H.; Benson, Gwen

    2008-01-01

    The National Commission on Teaching and America's Future (NCTAF) and Georgia State University (GSU) developed a model for induction of new teachers in urban high need schools. A model induction program, developed over the three-year implementation period, includes: (1) The BRIDGE (Building Resources: Induction and Development for Georgia…

  16. Structured Statistical Models of Inductive Reasoning

    ERIC Educational Resources Information Center

    Kemp, Charles; Tenenbaum, Joshua B.

    2009-01-01

    Everyday inductive inferences are often guided by rich background knowledge. Formal models of induction should aim to incorporate this knowledge and should explain how different kinds of knowledge lead to the distinctive patterns of reasoning found in different inductive contexts. This article presents a Bayesian framework that attempts to meet…

  17. Propofol Induction's Effect on Cardiac Function

    ClinicalTrials.gov

    2015-03-31

    This Study Was Focused to Evaluate Feasibility of Doppler Tissue Monitoring During the Induction Anesthesia,; and Evaluate Routine Propofol Induction's Effect on Myocardial Tissue Motion, Using Non-invasive Doppler Tissue and 2D Speckle Tracking Imaging.; This is the First Study, to Our Knowledge, Which Has Evaluated the Possible Impact of Propofol Induction on LV Function.

  18. Energy saving concepts relating to induction generators

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1980-01-01

    Energy saving concepts relating to induction generators are presented. The first describes a regenerative scheme using an induction generator as a variable load for prime movers under test is described. A method for reducing losses in induction machines used specifically as wind driven generators is also described.

  19. A Retrospective Appraisal of Teacher Induction

    ERIC Educational Resources Information Center

    Nasser-Abu Alhija, Fadia M.; Fresko, Barbara

    2016-01-01

    Examination of an induction program for new teachers was undertaken from the viewpoint of induction graduates three years after participation. Their retrospective perspectives were investigated as to their satisfaction with assimilation in school in the induction year, their attitudes towards organizational aspects of the program, and the…

  20. Regulation by phosphorylation of Xenopus laevis poly(ADP-ribose) polymerase enzyme activity during oocyte maturation.

    PubMed Central

    Aoufouchi, S; Shall, S

    1997-01-01

    Poly(ADP-ribose) polymerase (PARP) is an abundant nuclear enzyme that is dependent on DNA breaks and nicks for its enzyme activity. These DNA nicks and breaks function as allosteric effectors of the enzyme activity. This reaction is important for efficient DNA base excision repair, although it is not a component of the elementary repair pathway itself. The physiological relevance of this reaction might be to ensure correct and efficient DNA repair. We have examined the enzyme activity of PARP in oocytes and eggs of Xenopus laevis. Although both oocytes and eggs contain approximately the same amounts of enzyme protein, there is no detectable enzyme activity in the oocytes, whereas in the eggs the enzyme is active. Enzyme activity appears during oocyte maturation, approx. 4 h after induction by progesterone. This enzyme activation coincides with the appearance of active maturation-promoting factor. Enzyme activation is accompanied by a shift in the electrophoretic mobility of the polypeptide, from an apparent molecular mass of 116 kDa to 125 kDa. Treatment with either bacterial or potato phosphatase reverses the mobility shift and abolishes enzyme activity. Incubation of maturing X. laevis eggs with radioactive inorganic phosphate and subsequent immunoprecipitation demonstrate that the PARP protein is phosphorylated in vivo. We show that maturation-promoting factor (Cyclin B/cdc2) cannot itself be responsible for the phosphorylation and activation of PARP in maturing X. laevis eggs. Together, these results demonstrate that the enzyme activity of PARP in X. laevis oocytes and eggs is regulated by post-translational, covalent phosphorylation. PMID:9230139

  1. Quality Teacher Induction: "Fourth-Wave" (1997-2006) Induction Programs

    ERIC Educational Resources Information Center

    Wood, Ann L.; Stanulis, Randi Nevins

    2009-01-01

    The purpose of this essay is to describe quality teacher induction that has evolved from "fourth-wave" (1997-2006) teacher induction program development and research. A definition of quality induction is proposed, and a set of induction goals and components are outlined. Understandings gained from fourth-wave programs are described, including ways…

  2. Children's Evaluations of Inductive Discipline as a Function of Transgression Type and Induction Orientation.

    ERIC Educational Resources Information Center

    Horton, Nicole K.; Ray, Glen E.; Cohen, Robert

    2001-01-01

    Examined second-, third-, fifth-, and sixth-graders' evaluations of parent-child inductive discipline situations. Found that for physical transgressions, victim-oriented induction was evaluated as more appropriate and fair than parent-oriented induction. Younger children evaluated parent-oriented induction as more appropriate than older children.…

  3. Teacher Induction: A New Beginning. Papers from the National Commission on the Induction Process.

    ERIC Educational Resources Information Center

    Brooks, Douglas M., Ed.

    The following papers are included in this monograph that provides a synthesis on beginning teacher induction: (1) "Teacher Induction" (Leslie Huling-Austin); (2) "Local Induction Programs" (Ralph Kester and Mary Marockie); (3) "Statewide Teacher Induction Programs" (Parmalee Hawk and Shirley Robards); (4) "The Role of Institutions of Higher…

  4. The Escherichia coli glucose transporter enzyme IICBGlc recruits the global repressor Mlc

    PubMed Central

    Nam, Tae-Wook; Cho, Seung-Hyon; Shin, Dongwoo; Kim, Ja-Hee; Jeong, Jin-Young; Lee, Joon-Hee; Roe, Jung-Hye; Peterkofsky, Alan; Kang, Sa-Ouk; Ryu, Sangryeol; Seok, Yeong-Jae

    2001-01-01

    In addition to effecting the catalysis of sugar uptake, the bacterial phosphoenolpyruvate:sugar phosphotransferase system regulates a variety of physiological processes. Exposure of cells to glucose can result in repression or induction of gene expression. While the mechanism for carbon catabolite repression by glucose was well documented, that for glucose induction was not clearly understood in Escherichia coli. Recently, glucose induction of several E.coli genes has been shown to be mediated by the global repressor Mlc. Here, we elucidate a general mechanism for glucose induction of gene expression in E.coli, revealing a novel type of regulatory circuit for gene expression mediated by the phosphorylation state-dependent interaction of a membrane-bound protein with a repressor. The dephospho-form of enzyme IICBGlc, but not its phospho-form, interacts directly with Mlc and induces transcription of Mlc-regulated genes by displacing Mlc from its target sequences. Therefore, the glucose induction of Mlc-regulated genes is caused by dephosphorylation of the membrane-bound transporter enzyme IICBGlc, which directly recruits Mlc to derepress its regulon. PMID:11157755

  5. Engineering Cellulase Enzymes for Bioenergy

    NASA Astrophysics Data System (ADS)

    Atreya, Meera Elizabeth

    Sustainable energy sources, such as biofuels, offer increasingly important alternatives to fossil fuels that contribute less to global climate change. The energy contained within cellulosic biofuels derives from sunlight energy stored in the form of carbon-carbon bonds comprising sugars such as glucose. Second-generation biofuels are produced from lignocellulosic biomass feedstocks, including agricultural waste products and non-food crops like Miscanthus, that contain lignin and the polysaccharides hemicellulose and cellulose. Cellulose is the most abundant biological material on Earth; it is a polymer of glucose and a structural component of plant cell walls. Accessing the sugar is challenging, as the crystalline structure of cellulose resists degradation; biochemical and thermochemical means can be used to depolymerize cellulose. Cellulase enzymes catalyze the biochemical depolymerization of cellulose into glucose. Glucose can be used as a carbon source for growth of a biofuel-producing microorganism. When it converts glucose to a hydrocarbon fuel, this microbe completes the biofuels process of transforming sunlight energy into accessible, chemical energy capable of replacing non-renewable transportation fuels. Due to strong intermolecular interactions between polymer chains, cellulose is significantly more challenging to depolymerize than starch, a more accessible polymer of glucose utilized in first-generation biofuels processes (often derived from corn). While most mammals cannot digest cellulose (dietary fiber), certain fungi and bacteria produce cellulase enzymes capable of hydrolyzing it. These organisms secrete a wide variety of glycoside hydrolase and other classes of enzymes that work in concert. Because cellulase enzymes are slow-acting and expensive to produce, my aim has been to improve the properties of these enzymes as a means to make a cellulosic biofuels process possible that is more efficient and, consequently, more economical than current

  6. [The rise of enzyme engineering in China].

    PubMed

    Li, Gaoxiang

    2015-06-01

    Enzyme engineering is an important part of the modern biotechnology. Industrial biocatalysis is considered the third wave of biotechnology following pharmaceutical and agricultural waves. In 25 years, China has made a mighty advances in enzyme engineering research. This review focuses on enzyme genomics, enzyme proteomics, biosynthesis, microbial conversion and biosensors in the Chinese enzyme engineering symposiums and advances in enzyme preparation industry in China. PMID:26672358

  7. Non-carbon induction furnace

    DOEpatents

    Holcombe, C.E.; Masters, D.R.; Pfeiler, W.A.

    1984-01-06

    The present invention is directed to an induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of non-carbon materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloys. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an rf induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650/sup 0/C for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.

  8. Carbon-free induction furnace

    DOEpatents

    Holcombe, Cressie E.; Masters, David R.; Pfeiler, William A.

    1985-01-01

    An induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of carbon free materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloy. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an RF induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650.degree. C. for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.

  9. Online Monitoring of Induction Motors

    SciTech Connect

    McJunkin, Timothy R.; Agarwal, Vivek; Lybeck, Nancy Jean

    2016-01-01

    The online monitoring of active components project, under the Advanced Instrumentation, Information, and Control Technologies Pathway of the Light Water Reactor Sustainability Program, researched diagnostic and prognostic models for alternating current induction motors (IM). Idaho National Laboratory (INL) worked with the Electric Power Research Institute (EPRI) to augment and revise the fault signatures previously implemented in the Asset Fault Signature Database of EPRI’s Fleet Wide Prognostic and Health Management (FW PHM) Suite software. Induction Motor diagnostic models were researched using the experimental data collected by Idaho State University. Prognostic models were explored in the set of literature and through a limited experiment with 40HP to seek the Remaining Useful Life Database of the FW PHM Suite.

  10. Induction plasma spraying of ceramics

    NASA Astrophysics Data System (ADS)

    Fan, Xiao-Bao; Gougeon, Patrick; Gitzhofer, Francois; Boulos, Maher

    A study is carried out on the influence of in-flight particle parameters on their splatting properties during the induction plasma deposition of ceramics. Results are presented for alumina powders with mean particle diameters of 21 microns and 82 microns under soft vacuum conditions. The chamber pressure was varied between 46.6 and 66.6 kPa. Measurements are carried out on the particle surface temperature and velocity prior to impact on stainless steel substrates. The form of the splat obtained is evaluated using SEM. The results are used for the parametric optimization of the induction plasma spraying process. Thick alumina coatings with total porosities as low as 2 percent were obtained.

  11. Electromagnetic induction in the moon

    NASA Technical Reports Server (NTRS)

    Sonett, C. P.

    1982-01-01

    The moon constitutes a nonhydromagnetic, but electrically conducting, target for the solar wind whose response reaches a peak as frequency increases and diminishes with further increase in frequency, suggesting the presence of the magnetic quadrupole moment. Magnetometer measurements of induction using Explorer and Apollo instruments are studied from both the harmonic and transient standpoint, and the resulting determination of internal bulk electrical conductivity is discussed. The closeness of the estimated internal temperature to the Ringwood-Essene solidus at 150-250 km depths suggests a layer of enhanced conductivity in lieu of high temperature. A reduced core radius estimate with a one-sigma upper limit of 360 km is reported. The discussion of lunar electrodynamics presented is restricted to the problem of induction, with only passing reference to flow fields and regional electric fields.

  12. Magneto-inductive conductivity sensor

    NASA Astrophysics Data System (ADS)

    Floume, Timmy

    2011-12-01

    Multi-element inductive coil systems are used to measure locally resolved conductivity profile. Usually such sensors rely on the separate interrogation of each coil. In addition, the coils must generally be magnetically decoupled for accurate signal processing. Here we demonstrate a metamaterial conductivity sensor that uses broadband interrogation of a line of coupled resonators. No decoupling is needed, which allows a transmission measurement to be carried out. The resonant elements of the metamaterial are coupled with each other and their neighbourhood which affects their quality factor. We derive analytically an algorithm to extract the local perturbation in each element from the modal measurement. We investigate numerically the performance of the sensor and derive an optimal configuration in terms of nearest neighbour coupling and the initial non-uniformity. Finally we implement a four-element magneto inductive conductivity sensor and show that a conductive perturbation along the line can be accurately reconstructed. Generalisation to higher number of elements is also discussed.

  13. Inductive shearing of drilling pipe

    DOEpatents

    Ludtka, Gerard M.; Wilgen, John; Kisner, Roger; Mcintyre, Timothy

    2016-04-19

    Induction shearing may be used to cut a drillpipe at an undersea well. Electromagnetic rings may be built into a blow-out preventer (BOP) at the seafloor. The electromagnetic rings create a magnetic field through the drillpipe and may transfer sufficient energy to change the state of the metal drillpipe to shear the drillpipe. After shearing the drillpipe, the drillpipe may be sealed to prevent further leakage of well contents.

  14. Segmented rail linear induction motor

    DOEpatents

    Cowan, Jr., Maynard; Marder, Barry M.

    1996-01-01

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.

  15. Segmented rail linear induction motor

    DOEpatents

    Cowan, M. Jr.; Marder, B.M.

    1996-09-03

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces. 6 figs.

  16. Electromagnetic induction in the Earth

    NASA Astrophysics Data System (ADS)

    Fergurson, Ian; Slater, Lee; Queralt, Pilar; Ledo, Juanjo

    Measurements of electrical properties of the Earth using electromagnetic induction (EM) can elucidate geological structures and processes ranging from meter to mantle scale. The 18th International Workshop on Electromagnetic Induction in the Earth (EMIW) highlighted how recent theoretical and instrumental advances are being applied in high-quality EM induction studies from around the world, at lithospheric, crustal, and near-surface scales.Important aspects of the lithospheric and crustal studies presented included the demonstration of the increased resolution provided by dense two-dimensional magnetotelluric (MT) profiles and three-dimensional grids, the common use of the improved impedance tensor decomposition method to correct regional MT responses, widespread consideration of implicitly anisotropic materials within multidimensional MT models, and, in the numerical modeling field, the increased use of unstructured meshes. Review papers provided an overview of the large-scale EM surveys and spatial variations in the European lithosphere and addressed the role of EM in monitoring seismic and volcanic crustal processes.

  17. Traveling-wave induction launchers

    NASA Technical Reports Server (NTRS)

    Elliott, David G.

    1989-01-01

    An analysis of traveling-wave induction launchers shows that induction is a feasible method of producing armature current and that efficient accelerators can be built without sliding contacts or arcs. In a traveling-wave induction launcher the armature current is induced by a slip speed between the armature and a traveling magnetic field. At 9 m/s slip speed a 9 kg projectile with an aluminum armature weighing 25 percent of the total mass can be accelerated to 3000 m/s in a 5 m-long barrel with a total ohmic loss in the barrel coils and armature of 4 percent of the launch kinetic energy and with an average armature temperature rise of 220 deg C, but a peak excitation frequency of 8600 Hz is required. With a 2 kg launch mass the ohmic loss is 7 percent. A launcher system optimized for rotating generators would have a peak frequency of 4850 Hz; with an aluminum armature weighing 33 percent of the launch mass and a slip speed of 30 m/s the total ohmic loss in the generators, cables, and accelerator would be 43 percent of the launch kinetic energy, and the average armature temperature rise would be 510 deg C.

  18. Energy harvesting via ferrofluidic induction

    NASA Astrophysics Data System (ADS)

    Monroe, J. G.; Vasquez, Erick S.; Aspin, Zachary S.; Fairley, John D.; Walters, Keisha B.; Berg, Matthew J.; Thompson, Scott M.

    2015-05-01

    A series of experiments were conducted to investigate and characterize the concept of ferrofluidic induction - a process for generating electrical power via cyclic oscillation of ferrofluid (iron-based nanofluid) through a solenoid. Experimental parameters include: number of bias magnets, magnet spacing, solenoid core, fluid pulse frequency and ferrofluid-particle diameter. A peristaltic pump was used to cyclically drive two aqueous ferrofluids, consisting of 7-10 nm iron-oxide particles and commercially-available hydroxyl-coated magnetic beads (~800 nm), respectively. The solutions were pulsated at 3, 6, and 10 Hz through 3.2 mm internal diameter Tygon tubing. A 1000 turn copper-wire solenoid was placed around the tube 45 cm away from the pump. The experimental results indicate that the ferrofluid is capable of inducing a maximum electric potential of approximately +/- 20 μV across the solenoid during its cyclic passage. As the frequency of the pulsating flow increased, the ferro-nanoparticle diameter increased, or the bias magnet separation decreased, the induced voltage increased. The type of solenoid core material (copper or plastic) did not have a discernible effect on induction. These results demonstrate the feasibility of ferrofluidic induction and provide insight into its dependence on fluid/flow parameters. Such fluidic/magneto-coupling can be exploited for energy harvesting and/or conversion system design for a variety of applications.

  19. Human cytosolic thymidine kinase: purification and physical characterization of the enzyme from HeLa cells

    SciTech Connect

    Sherley, J.L.; Kelly, T.J.

    1988-01-05

    The mammalian cytosolic thymidine kinase is one of a number of enzymes involved in DNA replication whose activities increase dramatically during S phase of the cell cycle. As a first step in defining the mechanisms that control the S phase induction of thymidine kinase activity, the authors have purified the human enzyme from HeLa cells and raised a specific immune serum against the purified protein. The enzyme was isolated from cells arrested in S phase by treatment with methotrexate and purified to near homogeneity by ion-exchange and affinity chromatography. Stabilization of the purified enzyme was achieved by the addition of digitonin. An electrophoretic R/sub m/ of 0.2 in nondenaturing gels characterizes the purified enzyme activity as cytosolic thymidine kinase. The enzyme has a Stoke's radius of 40 A determined by gel filtration and a sedimentation coefficient of 5.5 S determined by glycerol gradient sedimentation. Based on these hydrodynamic values, a native molecular weight of 96,000 was calculated for the purified enzyme. When electrophoresed in denaturing sodium dodecyl sulfate-polyacrylamide gels under reducing conditions, the most purified enzyme fraction was found to contain one predominant polypeptide of M/sub r/ = 24,000. Several lines of evidence indicate that this polypeptide is responsible for thymidine kinase enzymatic activity.

  20. Vanadate and selenium inhibit the triiodothyronine induced enzyme activity and mRNA level for both fatty acid synthase and malic enzyme

    SciTech Connect

    Zhu, Y.; Mirmiran, R.; Goodridge, A.G.; Stapleton, S.R. Western Michigan Univ., Kalamazoo )

    1991-03-15

    In chick-embryo hepatocytes in culture, triiodothyronine stimulates enzyme activity, mRNA level and transcription rate for both fatty acid synthase (FAS) and malic enzyme (ME). Insulin alone has no effect but amplifies the induction by T3. Recent evidence has demonstrated the insulin-mimicking action of vanadate and selenium on various physiological processes. Little information, however, is available on the affects of vanadate and selenium on the expression of genes that are regulated by insulin. These studies were initiated to test the potential of vanadate and selenium to mimic the amplification affect of insulin on the T3 induction of FAS and ME. In chick-embryo hepatocytes incubated in a chemically defined medium, addition of T3 for 48h causes an increase in the enzyme activity and mRNA level for both FAS and ME. Addition of sodium vanadate or sodium selenate (20 {mu}M) coincident with the T3 almost completely inhibited the stimulation of FAS and ME activity and accumulation of their respective mRNA's. Fifty percent maximal inhibition occurred at about 3-40{mu}M vanadate or 5-10{mu}M selenium. Vanadate and selenium similarity inhibited FAS and ME enzyme activity and mRNA level when the cells were incubated in the presence of insulin and T3. The effect of these metals was selective; isocitrate dehydrogenase activity as well as the level of glyceraldehyde 3-phosphate mRNA were not affected by any of the additions made to the cells in culture. This effect by vanadate and selenium also does not appear to be a generalized effect of metals on lipogenic enzymes as molydate under similar experimental conditions has no effect on either the enzyme activity or mRNA level of FAS or ME. Studies are continuing to determine the mechanism of action of these agents on the regulation of lipogenic enzymes.

  1. Enzyme exposure and enzyme sensitisation in the baking industry.

    PubMed Central

    Vanhanen, M; Tuomi, T; Hokkanen, H; Tupasela, O; Tuomainen, A; Holmberg, P C; Leisola, M; Nordman, H

    1996-01-01

    OBJECTIVES: To assess the exposure to enzymes and prevalence of enzyme sensitisation in the baking industry. METHODS: A cross sectional study was conducted in four bakeries, one flour mill, and one crispbread factory. Sensitisation to enzymes, flours, and storage mites was examined by skin prick and radioallergosorbent (RAST) tests. 365 workers were tested. The workers were interviewed for work related respiratory and skin symptoms. Total dust concentrations were measured by a gravimetric method, and the concentration of alpha-amylase in air was measured by a catalytic method. An immunochemical method was used for measuring cellulase and xylanase in air. RESULTS: Total measured dust concentrations were from 0.1 to 18 mg/m3, with highest values in dough making areas of bakeries. The alpha-amylase concentrations generally followed the total dust concentrations and reached the highest values < 6.6 micrograms/m3 in the same areas. Cellulase and xylanase varied with concentrations < 180 ng/m3 and < 40 ng/m3, respectively, in the flour mill and the crispbread factory. No cellulase, but concentrations of 1-200 ng/m3 xylanase, were found in the bakeries, probably indicating the natural xylanase activity of wheat. 12 workers (8%) in the bakeries, three (5%) in the flour mill, and four (3%) in the crispbread factory were skin prick positive to enzymes. The corresponding percentages of positive reactions to flours were 12%, 5%, and 8%. CONCLUSIONS: The study confirmed that industrial enzymes in baking used as additives in a powdered form pose a risk of sensitisation. The no effect air concentrations for industrial enzymes are not known. Based on present knowledge, however, lowering exposures and eliminating short and high peaks by technical measures would lower the risk of sensitisation. This would be most effectively accomplished by shifting to non-dusty products. PMID:8943831

  2. Developmental Regulation of Enzymes of Indole Alkaloid Biosynthesis in Catharanthus roseus1

    PubMed Central

    De Luca, Vincenzo; Fernandez, Jesus Alvarez; Campbell, Douglas; Kurz, Wolfgang G. W.

    1988-01-01

    Developing seedlings of Catharanthus roseus were analyzed for appearance of tryptophan decarboxylase (TDC), strictosidine synthase (SS), N-methyltransferase (NMT) and O-acetyltransferase (DAT) enzyme activities. SS enzyme activity appeared early after germination and was present throughout most of the developmental study. TDC activity was highly regulated and peaked over a 48 hour period achieving a maximum by day of 5 of seedling development. Both TDC and SS were present in all tissues of the seedling. NMT and DAT enzyme activities were induced after TDC and SS had peaked and these activities could only be found in hypocotyls and cotyledons. TDC, SS, and NMT did not require light for induction whereas DAT enzyme activity was increased approximately 10-fold after light treatment of dark grown seedlings. PMID:16665928

  3. Production of Enzymes from Agroindustrial Wastes by Biosurfactant-Producing Strains of Bacillus subtilis.

    PubMed

    Barros, Francisco Fábio Cavalcante; Simiqueli, Ana Paula Resende; de Andrade, Cristiano José; Pastore, Gláucia Maria

    2013-01-01

    Bacteria in the genus Bacillus are the source of several enzymes of current industrial interest. Hydrolases, such as amylases, proteases, and lipases, are the main enzymes consumed worldwide and have applications in a wide range of products and industrial processes. Fermentation processes by Bacillus subtilis using cassava wastewater as a substrate are reported in the technical literature; however, the same combination of microorganisms and this culture medium is limited or nonexistent. In this paper, the amylase, protease, and lipase production of ten Bacillus subtilis strains previously identified as biosurfactant producers in cassava wastewater was evaluated. The LB1a and LB5a strains were selected for analysis using a synthetic medium and cassava wastewater and were identified as good enzyme producers, especially of amylases and proteases. In addition, the enzymatic activity results indicate that cassava wastewater was better than the synthetic medium for the induction of these enzymes. PMID:23533780

  4. Modelling Of Chlorine Inductive Discharges

    NASA Astrophysics Data System (ADS)

    Chabert P.; Despiau-Pujo, E.

    2010-07-01

    III-V compounds such as GaAs, InP or GaN-based materials are increasingly important for their use in optoelectronic applications, especially in the telecommunications and light detection industries. Photonic devices including lasers, photodetectors or LEDs, require reliable etching processes characterized by high etch rate, profile control and low damage. Although many problems remain to be understood, inductively coupled discharges seem to be promising to etch such materials, using Cl2/Ar, Cl2/N2 and Cl2/H2 gas chemistries. Inductively coupled plasma (ICP) sources meet most of the requirements for efficient plasma processing such as high etch rates, high ion densities and low controllable ion energies. However, the presence of a negative ion population in the plasma alters the positive ion flux, reduces the electron density, changes the electron temperature, modifies the spatial structure of the discharge and can cause unstable operation. Several experimental studies and numerical simulation results have been published on inductively coupled Cl2/Ar plasmas but relatively few systematic comparisons of model predictions and experimental data have been reported in given reactor geometries under a wide range of op- erating conditions. Validation of numerical predictions is essential for chemically complex plasma processing and there is a need to benchmark the models with as many measurements as possible. In this paper, comparisons of 2D fluid simulations with experimental measurements of Ar/Cl2 plasmas in a low pressure ICP reactor are reported (Corr et al. 2008). The electron density, negative ion fraction and Cl atom density are investigated for various conditions of Ar/Cl2 ratio, gas pressure and applied RF power in H mode. Simulations show that the wall recombination coefficient of Cl atom (?) is a key parameter of the model and that neutral densities are very sensitive to its variations. The best agreement between model and experiment is obtained for ? = 0

  5. Subcellular localization of pituitary enzymes

    NASA Technical Reports Server (NTRS)

    Smith, R. E.

    1970-01-01

    A cytochemical procedure is reported for identifying subcellular sites of enzymes hydrolyzing beta-naphthylamine substrates, and to study the sites of reaction product localization in cells of various tissues. Investigations using the substrate Leu 4-methoxy-8-naphthylamine, a capture with hexonium pararosaniline, and the final chelation of osmium have identified the hydrolyzing enzyme of rat liver cells; this enzyme localized on cell membranes with intense deposition in the areas of the parcanaliculi. The study of cells in the anterior pituitary of the rat showed the deposition of reaction product on cell membrane; and on the membranes of secretion granules contained within the cell. The deposition of reaction product on the cell membrane however showed no increase or decrease with changes in the physiological state of the gland and release of secretion granules from specific cells.

  6. Micromotors Powered by Enzyme Catalysis.

    PubMed

    Dey, Krishna K; Zhao, Xi; Tansi, Benjamin M; Méndez-Ortiz, Wilfredo J; Córdova-Figueroa, Ubaldo M; Golestanian, Ramin; Sen, Ayusman

    2015-12-01

    Active biocompatible systems are of great current interest for their possible applications in drug or antidote delivery at specific locations. Herein, we report the synthesis and study of self-propelled microparticles powered by enzymatic reactions and their directed movement in substrate concentration gradient. Polystyrene microparticles were functionalized with the enzymes urease and catalase using a biotin-streptavidin linkage procedure. The motion of the enzyme-coated particles was studied in the presence of the respective substrates, using optical microscopy and dynamic light scattering analysis. The diffusion of the particles was found to increase in a substrate concentration dependent manner. The directed chemotactic movement of these enzyme-powered motors up the substrate gradient was studied using three-inlet microfluidic channel architecture. PMID:26587897

  7. Molecular basis of bilirubin UDP-glucuronosyltransferase induction in spontaneously diabetic rats, acetone-treated rats and starved rats.

    PubMed Central

    Braun, L; Coffey, M J; Puskás, F; Kardon, T; Nagy, G; Conley, A A; Burchell, B; Mandl, J

    1998-01-01

    The co-ordinated induction of several hepatic drug-metabolizing enzymes is a common feature in the regulation of drug biotransformation under normal and pathological conditions. In the present study the activity and expression of bilirubin UDP-glucuronosyltransferase (UGT1A1) were investigated in livers of BioBreeding/Worcester diabetic, fasted and acetone-treated rats. Bilirubin glucuronidation was stimulated by all three treatments; this was correlated with an increase in the UGT1A1 protein concentration in hepatic microsomes. Transcriptional induction of UGT1A1 was also observed in diabetes and starvation but not with acetone treatment, which apparently caused translational stabilization of the enzyme protein. The hormonal/metabolic alterations in diabetes and starvation might be a model for postnatal development. The sudden interruption of maternal glucose supply signals the enhanced expression of UGT1A1, giving a novel explanation for the physiological induction of bilirubin glucuronidation in newborn infants. PMID:9841869

  8. Immunomodulatory Effects of Chitotriosidase Enzyme

    PubMed Central

    Elmonem, Mohamed A.; van den Heuvel, Lambertus P.; Levtchenko, Elena N.

    2016-01-01

    Chitotriosidase enzyme (EC: 3.2.1.14) is the major active chitinase in the human body. It is produced mainly by activated macrophages, in which its expression is regulated by multiple intrinsic and extrinsic signals. Chitotriosidase was confirmed as essential element in the innate immunity against chitin containing organisms such as fungi and protozoa; however, its immunomodulatory effects extend far beyond innate immunity. In the current review, we will try to explore the expanding spectrum of immunological roles played by chitotriosidase enzyme in human health and disease and will discuss its up-to-date clinical value. PMID:26881065

  9. Induction and Purification of Endo-β-N-Acetylglucosaminidase from Arthrobacter protophormiae Grown in Ovalbumin

    PubMed Central

    Takegawa, Kaoru; Nakoshi, Masanao; Iwahara, Shojiro; Yamamoto, Kenji; Tochikura, Tatsurokuro

    1989-01-01

    Arthrobacter protophormiae produced a high level of extracellular endo-β-N-acetylglucosaminidase when cells were grown in a medium containing ovalbumin. The enzyme was induced by the glycopeptide fraction of ovalbumin prepared by pronase digestion. Production of the enzyme was also induced by glycoproteins such as yeast invertase and bovine ribonuclease B but not by monosaccharides such as mannose, N-acetylglucosamine, and galactose. The enzyme was purified to homogeneity as demonstrated by polyacrylamide gel electrophoresis and has an apparent molecular weight of about 80,000. The enzyme showed a broad optimum pH in the range of pH 5.0 to 11.0. The enzyme hydrolyzed all heterogeneous ovalbumin glycopeptides, although the hydrolysis rates for hybrid type glycopeptides were very low. The substrate specificity of A. protophormiae endo-β-N-acetylglucosaminidase was very similar to that of Endo-CII from Clostridium perfringens. Therefore, the enzyme induction by A. protophormiae seems to have a close relation to the substrate specificity of the enzyme. PMID:16348072

  10. Host suitability and diet mixing influence activities of detoxification enzymes in adult Japanese beetles.

    PubMed

    Adesanya, Adekunle; Liu, Nannan; Held, David W

    2016-05-01

    Induction of cytochrome P450, glutathione S transferase (GST), and carboxylesterase (CoE) activity was measured in guts of the scarab Popillia japonica Newman, after consumption of single or mixed plant diets of previously ranked preferred (rose, Virginia creeper, crape myrtle and sassafras) or non-preferred hosts (boxelder, riverbirch and red oak). The goal of this study was to quantify activities of P450, GST and CoE enzymes in the midgut of adult P. japonica using multiple substrates in response to host plant suitability (preferred host vs non-preferred hosts), and single and mixed diets. Non-preferred hosts were only sparingly fed upon, and as a group induced higher activities of P450, GST and CoE than did preferred hosts. However, enzyme activities for some individual plant species were similar across categories of host suitability. Similarly, beetles tended to have greater enzyme activities after feeding on a mixture of plants compared to a single plant type, but mixing per se does not seem as important as the species represented in the mix. Induction of detoxification enzymes on non-preferred hosts, or when switching between hosts, may explain, in part, the perceived feeding preferences of this polyphagous insect. The potential consequences of induced enzyme activities on the ecology of adult Japanese beetles are discussed. PMID:26964493

  11. Cryopreserved human hepatocytes as alternative in vitro model for cytochrome p450 induction studies.

    PubMed

    Garcia, Martha; Rager, Joseph; Wang, Qing; Strab, Robert; Hidalgo, Ismael J; Owen, Albert; Li, Jibin

    2003-01-01

    Induction of cytochrome P450 (CYP) by drugs is one of major concerns for drug-drug interactions. Thus, the assessment of CYP induction by novel compounds is a vital component in the drug discovery and development processes. Primary human hepatocytes are the preferred in vitro model for predicting CYP induction in vivo. However, their use is hampered by the erratic supply of human tissue and donor-to-donor variability. Although cryopreserved hepatocytes have been recommended for short-term applications in suspension, their use in studies on induction of enzyme activity has been limited because of poor attachment and response to enzyme inducers. In this study, we report culture conditions that allowed the attachment of cryopreserved human hepatocytes and responsiveness to CYP inducers. We evaluated the inducibility of CYP1A1/2 and CYP3A4 enzymes in cryopreserved hepatocytes from three human donors. Cryopreserved human hepatocytes were cultured in serum-free medium for 4 d. They exhibited normal morphology and measurable viability as evaluated by the reduction of tetrazolium salts (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) by cellular dehydrogenases. Treatment with beta-naphthoflavone (10 microM) for 3 d increased ethoxyresorufin-O-deethylase activity (CYP1A1/2) by 6- to 11-fold over untreated cultures and increased CYP1A2 messenger ribonucleic acid (mRNA) expression by three- to eightfold. Similarly, treatment of cryopreserved human hepatocytes with rifampicin (25 microM) for 3 d increased testosterone 6 beta-hydroxylase activity (CYP3A4) by five- to eightfold over untreated cultures and increased CYP3A4 mRNA expression by four- to eightfold. The results suggest that cryopreserved human hepatocytes can be a suitable in vitro model for evaluating xenobiotics as inducers of CYP1A1/2 and CYP3A4 enzymes. PMID:14599235

  12. Call for an enzyme genomics initiative

    PubMed Central

    Karp, Peter D

    2004-01-01

    I propose an Enzyme Genomics Initiative, the goal of which is to obtain at least one protein sequence for each enzyme that has previously been characterized biochemically. There are 1,437 enzyme activities for which Enzyme Commission (EC) numbers have been assigned but no sequence can be found in public protein-sequence databases. PMID:15287973

  13. Taking the Mystery Out of Enzymes.

    ERIC Educational Resources Information Center

    DeYoung, H. Garrett

    1984-01-01

    Discusses structure and function of enzymes, design of new enzymes and enzyme substitutes, and enzyme uses in industry, medicine, and wastewater treatment. The latter is a low-cost method which can remove as much as 99 percent of toxic substances found in many industrial wastewater streams. (JN)

  14. Lessons for Inductive Germline Determination

    PubMed Central

    Seervai, Riyad N.H.; Wessel, Gary M.

    2015-01-01

    SUMMARY Formation of the germline in an embryo marks a fresh round of reproductive potential, yet the developmental stage and location within the embryo where the primordial germ cells (PGCs) form differs wildly among species. In most animals, the germline is formed either by an inherited mechanism, in which maternal provisions within the oocyte drive localized germ-cell fate once acquired in the embryo, or an inductive mechanism that involves signaling between cells that directs germ-cell fate. The inherited mechanism has been widely studied in model organisms such as Drosophila melanogaster, Caenorhabditis elegans, Xenopus laevis, and Danio rerio. Given the rapid generation time and the effective adaptation for laboratory research of these organisms, it is not coincidental that research on these organisms has led the field in elucidating mechanisms for germline specification. The inductive mechanism, however, is less well understood and is studied primarily in the mouse (Mus musculus). In this review, we compare and contrast these two fundamental mechanisms for germline determination, beginning with the key molecular determinants that play a role in the formation of germ cells across all animal taxa. We next explore the current understanding of the inductive mechanism of germ-cell determination in mice, and evaluate the hypotheses for selective pressures on these contrasting mechanisms. We then discuss the hypothesis that the transition between these determination mechanisms, which has happened many times in phylogeny, is more of a continuum than a binary change. Finally, we propose an analogy between germline determination and sex determination in vertebrates—two of the milestones of reproduction and development—in which animals use contrasting strategies to activate similar pathways. PMID:23450642

  15. Xenobiotic Metabolizing Enzyme and Transporter Gene Expression in Primary Cultures of Human Hepatocytes Modulated by ToxCast Chemicals

    EPA Science Inventory

    ToxCast chemicals were assessed for induction or suppression of xenobiotic metabolizing enzyme and transporter gene expression using primary human hepatocytes. The mRNA levels of 14 target and 2 control genes were measured: ABCB1, ABCB11, ABCG2, SLCO1B1, CYP1A1, CYP1A2, CYP2B6, C...

  16. Modulation of Xenobiotic Metabolizing Enzyme and Transporter Gene Expression in Primary Cultures of Human Hepatocytes by ToxCast Chemicals

    EPA Science Inventory

    ToxCast chemicals were assessed for induction or suppression of xenobiotic metabolizing enzyme and transporter gene expression using primary human hepatocytes. The mRNA levels of 14 target and 2 control genes were measured: ABCB1, ABCB11, ABCG2, SLCO1B1, CYP1A1, CYP1A2, CYP2B6, C...

  17. Induction by carrot allelochemicals of insecticide-metabolising enzymes in the southern armyworm (Spodoptera eridania).

    PubMed

    Brattsten, L B; Evans, C K; Bonetti, S; Zalkow, L H

    1984-01-01

    Carrot foliage monoterpenes induce cytochrome P-450 up to 2.9-fold, NADPH cytochrome c (P-450) reductase up to 1.6-fold, NADPH-oxidation up to 3.8-fold, aldrin epoxidation up to 1.5-fold in southern armyworm larval midgut tissues when incorporated in their diet at 0.2% for 3 days. Stigmasterol and ergosterol did not substantially induce microsomal oxidase activities and significantly inhibited GSH S-aryltransferase activity and sulfotransferase activity. Coumarin did not substantially affect microsomal oxidase and sulfotransferase activity but is the most potent inducer of GSH S-aryltransferase activity, increasing this activity 7-fold. None of the chemicals is acutely toxic to the sixth instar larvae or affect the larval weight gain except coumarin which significantly depressed the maximal body weight attained. PMID:6141878

  18. Smoke carcinogens cause bone loss through the aryl hydrocarbon receptor and induction of CYP1 enzymes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Smoking is a major risk factor for osteoporosis and fracture. Here, we show that smoke toxins and environmental chemicals such as benzo[a]pyrene (BaP), 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD), and 3-methyl cholanthrene, which are well known aryl hydrocarbon receptor (AHR) agonists, induce osteocla...

  19. Induction of hepatic drug metabolizing enzymes by coal fly ash in rats

    SciTech Connect

    Srivastava, P.K.; Singh, Y.; Tyagi, S.R.; Misra, U.K.

    1987-12-01

    The effect of intratracheal administration of fly ash, its benzene-extracted residue and the benzene extract has been studied on the activities of hepatic mixed-function oxidases in the rat. Fly ash and its fractions significantly increased the levels of cytochrome P-450, cytochrome b/sub 5/, cytochrome b/sub 5/ reductase, NADPH-cytochrome c reductase, aminopyrine N-demethylase, aniline hydroxylase, and glutathione S-transferase in a dose-dependent manner. Phenobarbital or 3-methylcholanthrene treatment along with the administration of fly ash or its fractions showed an additive effect on the activities of the mixed-function oxidases. The observed effects were due to chemical component, i.e., organic and inorganic fractions of fly ash, and not due to its particulate nature. This was shown by the administration of glass beads, which did not cause any alteration in the activities of hepatic mixed-function oxidases.

  20. COMPARATIVE ENZYME INDUCTION AND LINDANE METABOLISM IN RATS PRE-TREATED WITH VARIOUS ORGANOCHLORINE PESTICIDES

    EPA Science Inventory

    The comparative effect of 7 days pre-treatment with one of seven organochlorine pesticides on the metabolism of lindane in vivo and on the metabolism of EPN, p-nitroanisole and methyl orange in vitro was investigated. Mirex was the most potent inducer of the oxidative hydrolysis ...

  1. VAPOR SHIELD FOR INDUCTION FURNACE

    DOEpatents

    Reese, S.L.; Samoriga, S.A.

    1958-03-11

    This patent relates to a water-cooled vapor shield for an inductlon furnace that will condense metallic vapors arising from the crucible and thus prevent their condensation on or near the induction coils, thereby eliminating possible corrosion or shorting out of the coils. This is accomplished by placing, about the top, of the crucible a disk, apron, and cooling jacket that separates the area of the coils from the interior of the cruclbIe and provides a cooled surface upon whlch the vapors may condense.

  2. Ferromagnetic enhanced inductive plasma sources

    NASA Astrophysics Data System (ADS)

    Godyak, Valery

    2013-07-01

    The subject of this paper is the review of inductively coupled plasma (ICP) sources enhanced with ferromagnetic cores, FMICP, found in various applications, including plasma fusion, space propulsion, light sources, plasma chemistry and plasma processing of materials. The history of FMICP, early attempts for their realization, some recent developments and examples of successful FMICP devices are given here. A comparative study of FMICPs with conventional ICPs demonstrates their certain advantages in power transfer efficiency, power factor and their ability to operate without rf plasma potentials at low plasma densities and with small gaps, while effectively controlling plasma density profile.

  3. Indoleacetic Acid and the Synthesis of Glucanases and Pectic Enzymes

    PubMed Central

    Datko, Anne Harmon; Maclachlan, G. A.

    1968-01-01

    Indoleacetic acid (IAA) and/or inhibitors of DNA, RNA or protein synthesis were added to the apex of decapitated seedlings of Pisum sativum L. var. Alaska. At various times up to 4 days, enzymic protein was extracted from a segment of epicotyl immediately below the apex and assayed for its ability to hydrolyse polysaccharides or their derivatives. With the exception of amylase, the total amounts per segment of all of the tested enzymes increased due to IAA treatment. The development of β-1,4-glucanase (cellulase) activity per unit of protein or fresh weight proceeded according to a typical sigmoid induction curve. Pectinase was formed for about 2 days in control segments and IAA treatment resulted in continued synthesis for at least another 2 days provided cell division took place. β-1,3-glucanase and pectinesterase activities were only enhanced by IAA to the extent that total protein levels increased. Reaction mechanisms for these effects and functions for the enzymes during growth are discussed. PMID:16656834

  4. DT-diaphorase induction by lead acetate in the liver of rats

    SciTech Connect

    Arizono, K.; Sugiura, S.; Miyazato, S.; Takiguchi, M.; Ariyoshi, T.

    1996-07-01

    DT-diaphorase(NAD(P)H:(quinone acceptor)oxidoreductase) is a cytosolic enzyme, which is localized mainly in liver, kidney, and gastrointestinal tract suggested that DT-diaphorase has a role as a cellular control devise against radical formation. Moreover it is considered that DT-diaphorase has an important role in the cellular defense mechanism against cytotoxic and mutagenic compounds. This enzyme is induced by aromatic hydrocarbons such as 3-methylcholanthrene and antioxidants, and is an interesting enzyme from drug metabolism and toxicological aspects. Another series of studies first reported that the treatment of organotin compounds induces hepatic DT-diaphorase activity accompanied by thymus atrophy in rats. Second, the induction ability of hepatic DT-diaphorase of rats treated with lead acetate (PbAc) is high among various metals. Although organotin compounds produce both thymus atrophy and increased DT-diaphorase activity similar to 3-MC, PbAc causes no significant change in thymus weight. These findings suggest that there is a different mechanism involved in the induction of DT-diaphorase with PbAc than with organotin compounds. In the present study, the induction mechanism of DT-diaphorase by PbAc in the liver of rats was investigated. 16 refs., 4 figs.

  5. Thermodynamics of Enzyme-Catalyzed Reactions Database

    National Institute of Standards and Technology Data Gateway

    SRD 74 Thermodynamics of Enzyme-Catalyzed Reactions Database (Web, free access)   The Thermodynamics of Enzyme-Catalyzed Reactions Database contains thermodynamic data on enzyme-catalyzed reactions that have been recently published in the Journal of Physical and Chemical Reference Data (JPCRD). For each reaction the following information is provided: the reference for the data, the reaction studied, the name of the enzyme used and its Enzyme Commission number, the method of measurement, the data and an evaluation thereof.

  6. The enzymes associated with denitrification

    NASA Technical Reports Server (NTRS)

    Hochstein, L. I.; Tomlinson, G. A.

    1988-01-01

    The enzymes involved in the reduction of nitrogenous oxides are thought to be intermediates in denitrification processes. This review examines the roles of nitrate reductase, nitrite reductases, nitric oxide reductase, mechanisms of N-N bond formation, and nitrous oxide reductases.

  7. Insolubilized enzymes for food synthesis

    NASA Technical Reports Server (NTRS)

    Marshall, D. L.

    1972-01-01

    Cellulose matrix with numerous enzyme-coated silica particles of colloidal size permanently bound at various sites within matrix was produced that has high activity and possesses requisite physical characteristics for filtration or column operations. Product also allows coupling step in synthesis of edible food to proceed under mild conditions.

  8. Phage lytic enzymes targeting streptococci

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Streptococcal pathogens contribute to a wide variety of human and livestock diseases. There is a need for new antimicrobials to replace over-used conventional antibiotics. Bacteriophage (viruses that infect bacteria) endolysins (enzymes that help degrade the bacterial cell wall) are ideal candidat...

  9. ORGANOPHOSPHATE DEGRADING ENZYMES - PHASE I

    EPA Science Inventory

    Agave BioSystems in collaboration with Carl A. Batt proposes to develop decon-nanoparticles, which will leverage ongoing opportunities in enzyme engineering and the fabrication of functionalized magnetic nanoparticles. Enhanced performance will be engineered into the system t...

  10. Rapid-Equilibrium Enzyme Kinetics

    ERIC Educational Resources Information Center

    Alberty, Robert A.

    2008-01-01

    Rapid-equilibrium rate equations for enzyme-catalyzed reactions are especially useful because if experimental data can be fit by these simpler rate equations, the Michaelis constants can be interpreted as equilibrium constants. However, for some reactions it is necessary to use the more complicated steady-state rate equations. Thermodynamics is…

  11. Biological abatement of enzyme inhibitors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignocellulose pretreatments release phenolic compounds that cause enzyme inhibition and deactivation. Bio-abatement, the biological removal of furfurals, acetic acid and phenolics, may utilize fungal fermentation to metabolize these compounds to CO2, water, cell mass, and heat. Our work with Coni...

  12. Organoclay-enzyme film electrodes.

    PubMed

    Mbouguen, Justin Kemmegne; Ngameni, Emmanuel; Walcarius, Alain

    2006-09-25

    This paper aims at showing the interest of organoclays (clay minerals containing organic groups covalently attached to the inorganic particles) as suitable host matrices likely to immobilize enzymes onto electrode surfaces for biosensing applications. The organoclays used in this work were natural Cameroonian smectites grafted with either aminopropyl (AP) or trimethylpropylammonium (TMPA) groups. The first ones were exploited for their ability to anchor biomolecules by covalent bonding while the second category exhibited favorable electrostatic interactions with negatively charged enzymes due to ion exchange properties that were pointed out here by means of multisweep cyclic voltammetry. AP-clay materials were applied to the immobilization of glucose oxidase (GOD) and TMPA-clays for polyphenol oxidase (PPO) anchoring. When deposited onto the surface of platinum or glassy carbon electrodes as enzyme/organoclay films, these systems were evaluated as biosensing electrochemical devices for detection of glucose and catechol chosen as model analytes. The advantageous features of these organoclays were discussed by comparison to the performance of related film electrodes made of non-functionalized clays. It appeared that organoclays provide a favorable environment to enzymes activity, as highlighted from the biosensors characteristics and determination of Michaelis-Menten constants. PMID:17723706

  13. CYP4 Enzymes as potential drug targets: focus on enzyme multiplicity, inducers and inhibitors, and therapeutic modulation of 20-hydroxyeicosatetraenoic acid (20-HETE) synthase and fatty acid ω-hydroxylase activities

    PubMed Central

    Edson, Katheryne Z.; Rettie, Allan E.

    2014-01-01

    The Cytochrome P450 4 (CYP4) family of enzymes in humans is comprised of thirteen isozymes that typically catalyze the ω-oxidation of endogenous fatty acids and eicosanoids. Several CYP4 enzymes can biosynthesize 20-hydroxyeicosatetraenoic acid or 20-HETE, an important signaling eicosanoid involved in regulation of vascular tone and kidney reabsorption. Additionally, accumulation of certain fatty acids is a hallmark of the rare genetic disorders, Refsum disease and X-ALD. Therefore, modulation of CYP4 enzyme activity, either by inhibition or induction, is a potential strategy for drug discovery. Here we review the substrate specificities, sites of expression, genetic regulation, and inhibition by exogenous chemicals of the human CYP4 enzymes, and discuss the targeting of CYP4 enzymes in the development of new treatments for hypertension, stroke, certain cancers and the fatty acid-linked orphan diseases. PMID:23688133

  14. Catechins Variously Affect Activities of Conjugation Enzymes in Proliferating and Differentiated Caco-2 Cells.

    PubMed

    Lněničková, Kateřina; Procházková, Eliška; Skálová, Lenka; Matoušková, Petra; Bártíková, Hana; Souček, Pavel; Szotáková, Barbora

    2016-01-01

    The knowledge of processes in intestinal cells is essential, as most xenobiotics come into contact with the small intestine first. Caco-2 cells are human colorectal adenocarcinoma that once differentiated, exhibit enterocyte-like characteristics. Our study compares activities and expressions of important conjugation enzymes and their modulation by green tea extract (GTE) and epigallocatechin gallate (EGCG) using both proliferating (P) and differentiated (D) caco-2 cells. The mRNA levels of the main conjugation enzymes were significantly elevated after the differentiation of Caco-2 cells. However, no increase in conjugation enzymes' activities in differentiated cells was detected in comparison to proliferating ones. GTE/EGCG treatment did not affect the mRNA levels of any of the conjugation enzymes tested in either type of cells. Concerning conjugation enzymes activities, GTE/EGCG treatment elevated glutathione S-transferase (GST) activity by approx. 30% and inhibited catechol-O-methyltransferase (COMT) activity by approx. 20% in differentiated cells. On the other hand, GTE as well as EGCG treatment did not significantly affect the activities of conjugation enzymes in proliferating cells. Administration of GTE/EGCG mediated only mild changes of GST and COMT activities in enterocyte-like cells, indicating a low risk of GTE/EGCG interactions with concomitantly administered drugs. However, a considerable chemo-protective effect of GTE via the pronounced induction of detoxifying enzymes cannot be expected as well. PMID:27617982

  15. Induction process of trainees in pathology residency

    PubMed Central

    Siddiqui, Imran; Ali, Natasha

    2016-01-01

    This article describes the evolution of the induction process of pathology residency at The Aga Khan University hospital. The Department of Postgraduate Medical Education was established in 1985. The induction process is an exhaustive exercise that includes an admission test held simultaneously in Karachi, Hyderabad, Lahore, and Rawalpindi, followed by an interview of the shortlisted candidates. The pathology residency program was started 25 years ago and since then the induction process has undergone major changes with the course of time. PMID:27313487

  16. 7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be...

  17. 7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be...

  18. 7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be...

  19. 7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be...

  20. 7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be...

  1. Energy-Efficient Thermomagnetic and Induction Hardening

    SciTech Connect

    2009-02-01

    This factsheet describes a research project that will develop and test a hybrid thermomagnetic and induction hardening technology to replace conventional heat treatment processes in forging applications.

  2. Coherent inductive communications link for biomedical applications

    NASA Technical Reports Server (NTRS)

    Hogrefe, Arthur F. (Inventor); Radford, Wade E. (Inventor)

    1985-01-01

    A two-way coherent inductive communications link between an external transceiver and an internal transceiver located in a biologically implanted programmable medical device. Digitally formatted command data and programming data is transmitted to the implanted medical device by frequency shift keying the inductive communications link. Internal transceiver is powered by the inductive field between internal and external transceivers. Digitally formatted data is transmitted to external transceiver by internal transceiver amplitude modulating inductive field. Immediate verification of the establishment of a reliable communications link is provided by determining existence of frequency lock and bit phase lock between internal and external transceivers.

  3. Induction Technique: Beyond Simple Response to Suggestion.

    PubMed

    Barabasz, Arreed; Barabasz, Marianne

    2016-10-01

    The hypnotic induction is intended to induce hypnosis. This implies that what is sought is intended to go beyond what might be wrought by mere suggestion, expectancy, and social influence. The experimentally controlled research showing that the induction makes a difference and how small changes in wording of suggestions can produce orthogonal responses is briefly reviewed. This article explains the principles of induction and three critical phases of hypnotic induction in detail. An arm levitation scripted protocol demonstrating how to respond to the patient using the three phases to maximize responses to hypnotic suggestions is presented. PMID:27586048

  4. Experimental Demonstration of the Induction Synchrotron

    NASA Astrophysics Data System (ADS)

    Takayama, Ken; Arakida, Yoshio; Dixit, Tanuja; Iwashita, Taiki; Kono, Tadaaki; Nakamura, Eiji; Otsuka, Kazunori; Shimosaki, Yoshito; Torikai, Kota; Wake, Masayoshi

    2007-02-01

    We report an experimental demonstration of the induction synchrotron, the concept of which has been proposed as a future accelerator for the second generation of neutrino factory or hadron collider. The induction synchrotron supports a superbunch and a superbunch permits more charge to be accelerated while observing the constraints of the transverse space-charge limit. By using a newly developed induction acceleration system instead of radio-wave acceleration devices, a single proton bunch injected from the 500 MeV booster ring and captured by the barrier bucket created by the induction step voltages was accelerated to 6 GeV in the KEK proton synchrotron.

  5. Experimental Demonstration of the Induction Synchrotron

    SciTech Connect

    Takayama, Ken; Nakamura, Eiji; Arakida, Yoshio; Iwashita, Taiki; Kono, Tadaaki; Shimosaki, Yoshito; Wake, Masayoshi; Dixit, Tanuja; Otsuka, Kazunori; Torikai, Kota

    2007-02-02

    We report an experimental demonstration of the induction synchrotron, the concept of which has been proposed as a future accelerator for the second generation of neutrino factory or hadron collider. The induction synchrotron supports a superbunch and a superbunch permits more charge to be accelerated while observing the constraints of the transverse space-charge limit. By using a newly developed induction acceleration system instead of radio-wave acceleration devices, a single proton bunch injected from the 500 MeV booster ring and captured by the barrier bucket created by the induction step voltages was accelerated to 6 GeV in the KEK proton synchrotron.

  6. Mutation induction in bacteria after heavy ion irradiation

    NASA Technical Reports Server (NTRS)

    Horneck, G.; Kozubek, S.

    1994-01-01

    From a compilation of experimental data on the mutagenic effects of heavy ions in bacteria, main conclusions have been drawn as follows: (1) The mutagenic efficacy of heavy ions in bacteria depends on physical and biological variables. Physical variables are the radiation dose, energy and charge of the ion; the biological variables are the bacterial strain, the repair genotype of bacteria, and the endpoint investigated (type of mutation, induction of enzymes related to mutagenesis); (2) The responses on dose or fluence are mainly linear or linear quadratic. The quadratic component, if found for low LET radiation, is gradually reduced with increasing LET; (3) At low values of Z and LET the cross section of mutation induction sigma m (as well as SOS response, sigma sos. and lambda phage induction, sigma lambda versus LET curves can be quite consistently described by a common function which increases up to approximately 100 keV/mu m. For higher LET values, the sigma(m) versus LET curves show the so-called 'hooks' observed also for other endpoints; (4) For light ions (Z is less than or equal to 4), the cross sections mostly decrease with increasing ion energy, which is probably related to the decrease of the specific energy departed by the ion inside the sensitive volume (cell). For ions in the range of Z = 10, sigma(m) is nearly independent on the ion energy. For heavier ions (Z is greater than or equal to 16), sigma(m) increases with the energy up to a maximum or saturation around 10 MeV/u. The increment becomes steeper with increasing atomic number of the ion. It correlates with the increasing track radius of the heavy ion; (5) The mutagenic efficiency per lethal event changes slightly with ion energy, if Z is small indicating a rough correlation between cellular lethality and mutation induction, only. For ions of higher Z this relation increases with energy, indicating a change in the 'mode' of radiation action from 'killing-prone' to 'mutation-prone'; and (6

  7. Apoptosis Induction in Cancer Cells by Ultrasound Exposure

    NASA Astrophysics Data System (ADS)

    Watanabe, Akihiro; Kawai, Kazuaki; Sato, Toshio; Nishimura, Hiroyuki; Kawashima, Norimichi; Takeuchi, Shinichi

    2004-05-01

    The methods of suppressing cancer cell proliferation by ultrasound exposure were investigated to develop a new minimally invasive cancer treatment. A stainless-steel diaphragm with a bolt-clamped Langevin-type transducer (BLT) was attached to the bottom of a water tank in the ultrasound exposure system used in this study. Cancer cells of a mouse T lymphoma (EL-4) in a flask were exposed to ultrasound under various conditions of exposure time, ultrasound frequency, ultrasound waveform, and so forth. The number of cancer cells exposed to ultrasound decreased during the culturing process. In this study, it was proved by electrophoresis, enzyme activity measurement and morphological observation that cancer cell proliferation can be suppressed by apoptosis induction in cancer cells by ultrasound exposure.

  8. Induction of photolyase activity in wood frog (Rana sylvatica) embryos.

    PubMed

    Smith, M A; Kapron, C M; Berrill, M

    2000-10-01

    Rising ultraviolet-B (UVB, 280-320 nm) radiation has been proposed as a factor which may explain nonnormal amphibian population declines. Accordingly research has been directed toward estimating the photolyase activity of several amphibian species in order to predict a species' resilience to UV damage. Unfortunately, in spite of published research which demonstrated that the activity of one of the principal photorepair enzymes, photolyase, can be induced, these estimates did not address the potential for in vivo induction by environmental factors present in situ. We show here that wood frog (Rana sylvatica) embryos exposed to periods of ambient solar radiation (1) displayed significantly different photolyase activities from embryos exposed to equivalent periods of dark; and (2) were positively correlated with the UVB fluence received in vivo. Such results suggest that previous conclusions regarding the relationship between photorepair and population decline must be reevaluated. Estimating amphibian photorepair is a complicated process, and caution must be exercised when interpreting such data. PMID:11045732

  9. Transient repression of catabolite-sensitive enzyme synthesis elicited by 2,4-dinitrophenol.

    PubMed

    Oki, R

    1975-09-01

    Transient inhibition of catabolic enzyme synthesis in Escherichia coli occurred when a low concentration of 2,4-dinitrophenol (DNP) was simultaneously added with inducer. Using mutant strains defective for gamma-gene product or constitutive for lac enzymes, it was found that the inhibition is not due to the exclusion of inducer by uncoupling. The addition of cyclic adenosine 3',5'-monophosphate overcame repression. The components of the lac operon coordinately responded to DNP inhibition. From deoxyribonucleic acid-ribonucleic acid hybridization experiments, it was found that the inhibition of beta-galactosidase induction occurred at the level of messenger ribonucleic acid synthesis specific for the lac operon. It seems probable that DNP represses induction in a similar manner to that of transient repression observed upon the addition of glucose. Furthermore, it was found that transient repression disappeared if cells were preincubated with DNP before induction. This indicates that new contact of cells with DNP is obligatory for transient repression. From these results, it is suggested that the cell membrane may be responsible for regulation of catabolite-sensitive enzyme synthesis. PMID:169228

  10. Characterization of human cytochrome P450 induction by pesticides.

    PubMed

    Abass, Khaled; Lämsä, Virpi; Reponen, Petri; Küblbeck, Jenni; Honkakoski, Paavo; Mattila, Sampo; Pelkonen, Olavi; Hakkola, Jukka

    2012-03-29

    Pesticides are a large group of structurally diverse toxic chemicals. The toxicity may be modified by cytochrome P450 (CYP) enzyme activity. In the current study, we have investigated effects and mechanisms of 24 structurally varying pesticides on human CYP expression. Many pesticides were found to efficiently activate human pregnane X receptor (PXR) and/or constitutive androstane receptor (CAR). Out of the 24 compounds tested, 14 increased PXR- and 15 CAR-mediated luciferase activities at least 2-fold. While PXR was predominantly activated by pyrethroids, CAR was, in addition to pyrethroids, well activated by organophosphates and several carbamates. Induction of CYP mRNAs and catalytic activities was studied in the metabolically competent, human derived HepaRG cell line. CYP3A4 mRNA was induced most powerfully by pyrethroids; 50 μM cypermethrin increased CYP3A4 mRNA 35-fold. CYP2B6 was induced fairly equally by organophosphate, carbamate and pyrethroid compounds. Induction of CYP3A4 and CYP2B6 by these compound classes paralleled their effects on PXR and CAR. The urea herbicide diuron and the triazine herbicide atrazine induced CYP2B6 mRNA more than 10-fold, but did not activate CAR indicating that some pesticides may induce CYP2B6 via CAR-independent mechanisms. CYP catalyzed activities were induced much less than the corresponding mRNAs. At least in some cases, this is probably due to significant inhibition of CYP enzymes by the studied pesticides. Compared with human CAR activation and CYP2B6 expression, pesticides had much less effect on mouse CAR and CYP2B10 mRNA. Altogether, pesticides were found to be powerful human CYP inducers acting through both PXR and CAR. PMID:22310298

  11. Hypoxia Promotes Glycogen Accumulation through Hypoxia Inducible Factor (HIF)-Mediated Induction of Glycogen Synthase 1

    PubMed Central

    Pescador, Nuria; Garcia-Rocha, Mar; Ortiz-Barahona, Amaya; Vazquez, Silvia; Ordoñez, Angel; Cuevas, Yolanda; Saez-Morales, David; Garcia-Bermejo, Maria Laura; Landazuri, Manuel O.; Guinovart, Joan; del Peso, Luis

    2010-01-01

    When oxygen becomes limiting, cells reduce mitochondrial respiration and increase ATP production through anaerobic fermentation of glucose. The Hypoxia Inducible Factors (HIFs) play a key role in this metabolic shift by regulating the transcription of key enzymes of glucose metabolism. Here we show that oxygen regulates the expression of the muscle glycogen synthase (GYS1). Hypoxic GYS1 induction requires HIF activity and a Hypoxia Response Element within its promoter. GYS1 gene induction correlated with a significant increase in glycogen synthase activity and glycogen accumulation in cells exposed to hypoxia. Significantly, knockdown of either HIF1α or GYS1 attenuated hypoxia-induced glycogen accumulation, while GYS1 overexpression was sufficient to mimic this effect. Altogether, these results indicate that GYS1 regulation by HIF plays a central role in the hypoxic accumulation of glycogen. Importantly, we found that hypoxia also upregulates the expression of UTP:glucose-1-phosphate urydylyltransferase (UGP2) and 1,4-α glucan branching enzyme (GBE1), two enzymes involved in the biosynthesis of glycogen. Therefore, hypoxia regulates almost all the enzymes involved in glycogen metabolism in a coordinated fashion, leading to its accumulation. Finally, we demonstrated that abrogation of glycogen synthesis, by knock-down of GYS1 expression, impairs hypoxic preconditioning, suggesting a physiological role for the glycogen accumulated during chronic hypoxia. In summary, our results uncover a novel effect of hypoxia on glucose metabolism, further supporting the central importance of metabolic reprogramming in the cellular adaptation to hypoxia. PMID:20300197

  12. Ensuring Strong Induction Policies and Support. Induction Insights. Supporting Special Education Teachers - Policymakers [PII-6

    ERIC Educational Resources Information Center

    National Center to Inform Policy and Practice in Special Education Professional Development, 2010

    2010-01-01

    Strong induction programs influence novice special education teachers' determination to remain in teaching. Those who experience high levels of induction support tend to report greater job satisfaction and success in teaching challenging students. Although novice special education teachers can benefit from standard induction support, they also may…

  13. 38 CFR 21.282 - Effective date of induction into a rehabilitation program; retroactive induction.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... induction into a rehabilitation program; retroactive induction. 21.282 Section 21.282 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) VOCATIONAL REHABILITATION AND EDUCATION Vocational Rehabilitation and Employment Under 38 U.S.C. Chapter 31 Induction into A Rehabilitation...

  14. 38 CFR 21.282 - Effective date of induction into a rehabilitation program; retroactive induction.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... induction into a rehabilitation program; retroactive induction. 21.282 Section 21.282 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) VOCATIONAL REHABILITATION AND EDUCATION Vocational Rehabilitation and Employment Under 38 U.S.C. Chapter 31 Induction into A Rehabilitation...

  15. Urban Induction Policy and Practice: An Assessment of New Teacher Induction in the Urban Midwest

    ERIC Educational Resources Information Center

    Johnson, Lisa

    2009-01-01

    This article analyzes teacher induction policy and practice in 12 districts in the urban Midwest. Attention is paid to induction policy as well as the enactment of induction in urban, suburban, and rural school districts. Findings suggest marked differences between district programs and little difference between states despite different policy…

  16. Mobile inductively coupled plasma system

    DOEpatents

    D`Silva, A.P.; Jaselskis, E.J.

    1999-03-30

    A system is described for sampling and analyzing a material located at a hazardous site. A laser located remotely from the hazardous site is connected to an optical fiber, which directs laser radiation proximate the material at the hazardous site. The laser radiation abates a sample of the material. An inductively coupled plasma is located remotely from the material. An aerosol transport system carries the ablated particles to a plasma, where they are dissociated, atomized and excited to provide characteristic optical reduction of the elemental constituents of the sample. An optical spectrometer is located remotely from the site. A second optical fiber is connected to the optical spectrometer at one end and the plasma source at the other end to carry the optical radiation from the plasma source to the spectrometer. 10 figs.

  17. Floral induction in Eucalyptus nitens.

    PubMed

    Moncur, M W; Hasan, O

    1994-11-01

    Eucalyptus nitens (Deane & Maiden) Maiden takes at least five years to initiate flower buds from seed and is an infrequent and light flowerer. Because this behavior constitutes a major impediment to breeding programs, we examined the mechanisms controlling floral induction in E. nitens, with the long-term aim of reducing generation time and increasing seed yield. Application of paclobutrazol reduced the concentration of endogenous gibberellic acid (GA) in apical tissue and enhanced the reproductive activity of grafted trees maintained outside over winter in Canberra, Australia. Grafts maintained in a warm greenhouse over winter did not produce flower buds, despite the paclobutrazol-induced reduction in GA concentration of the apical tissue. Exposing untreated grafts, which had been maintained over winter in a warm greenhouse, to low temperature the following spring reduced growth but did not induce flower bud production. Addition of GA(3) to paclobutrazol-treated grafts reduced the effect of paclobutrazol on reproductive activity. PMID:14967619

  18. Element of an inductive coupler

    DOEpatents

    Hall, David R.; Fox, Joe

    2006-08-15

    An element for an inductive coupler in a downhole component comprises magnetically conductive material, which is disposed in a recess in annular housing. The magnetically conductive material forms a generally circular trough. The circular trough comprises an outer generally U-shaped surface, an inner generally U-shaped surface, and two generally planar surfaces joining the inner and outer surfaces. The element further comprises pressure relief grooves in at least one of the surfaces of the circular trough. The pressure relief grooves may be scored lines. Preferably the pressure relief grooves are parallel to the magnetic field generated by the magnetically conductive material. The magnetically conductive material is selected from the group consisting of soft iron, ferrite, a nickel iron alloy, a silicon iron alloy, a cobalt iron alloy, and a mu-metal. Preferably, the annular housing is a metal ring.

  19. Improvements of biomass deconstruction enzymes

    SciTech Connect

    Sale, K. L.

    2012-03-01

    Sandia National Laboratories and DSM Innovation, Inc. collaborated on the investigation of the structure and function of cellulases from thermophilic fungi. Sandia's role was to use its expertise in protein structure determination and X-ray crystallography to solve the structure of these enzymes in their native state and in their substrate and product bound states. Sandia was also tasked to work with DSM to use the newly solved structure to, using computational approaches, analyze enzyme interactions with both bound substrate and bound product; the goal being to develop approaches for rationally designing improved cellulases for biomass deconstruction. We solved the structures of five cellulases from thermophilic fungi. Several of these were also solved with bound substrate/product, which allowed us to predict mutations that might enhance activity and stability.

  20. Enzyme catalysis in ionic liquids.

    PubMed

    Kragl, Udo; Eckstein, Marrit; Kaftzik, Nicole

    2002-12-01

    Ionic liquids offer new possibilities for the application of solvent engineering to biocatalytic reactions. Although in many cases ionic liquids have simply been used to replace organic solvents, they have often led to improved process performance. Unlike conventional organic solvents, ionic liquids possess no vapor pressure, are able to dissolve many compounds, and can be used to form two-phase systems with many solvents. To date, reactions involving lipases have benefited most from the use of ionic liquids, but the use of ionic liquids with other enzymes and in whole-cell processes has also been described. In some cases, remarkable results with respect to yield, (enantio)selectivity or enzyme stability were observed. PMID:12482515

  1. Metrological aspects of enzyme production

    NASA Astrophysics Data System (ADS)

    Kerber, T. M.; Dellamora-Ortiz, G. M.; Pereira-Meirelles, F. V.

    2010-05-01

    Enzymes are frequently used in biotechnology to carry out specific biological reactions, either in industrial processes or for the production of bioproducts and drugs. Microbial lipases are an important group of biotechnologically valuable enzymes that present widely diversified applications. Lipase production by microorganisms is described in several published papers; however, none of them refer to metrological evaluation and the estimation of the uncertainty in measurement. Moreover, few of them refer to process optimization through experimental design. The objectives of this work were to enhance lipase production in shaken-flasks with Yarrowia lipolytica cells employing experimental design and to evaluate the uncertainty in measurement of lipase activity. The highest lipolytic activity obtained was about three- and fivefold higher than the reported activities of CRMs BCR-693 and BCR-694, respectively. Lipase production by Y. lipolytica cells aiming the classification as certified reference material is recommended after further purification and stability studies.

  2. Mineral induction by immobilized phosphoproteins

    NASA Technical Reports Server (NTRS)

    Saito, T.; Arsenault, A. L.; Yamauchi, M.; Kuboki, Y.; Crenshaw, M. A.

    1997-01-01

    Dentin phosphoproteins are thought to have a primary role in the deposition of mineral on the collagen of dentin. In this study we determined the type of binding between collagen and phosphoproteins necessary for mineral formation onto collagen fibrils and whether the phosphate esters are required. Bovine dentin phosphophoryn or phosvitin from egg yolk were immobilized on reconstituted skin type I collagen fibrils by adsorption or by covalent cross-linking. In some samples the ester phosphate was removed from the covalently cross-linked phosphoproteins by treatment with acid phosphatase. All samples were incubated at 37 degrees C in metastable solutions that do not spontaneously precipitate. Reconstituted collagen fibrils alone did not induce mineral formation. The phosphoproteins adsorbed to the collagen fibrils desorbed when the mineralization medium was added, and mineral was not induced. The mineral induced by the cross-linked phosphoproteins was apatite, and the crystals were confined to the surface of the collagen fibrils. With decreasing medium saturation the time required for mineral induction increased. The interfacial tensions calculated for apatite formation by either phosphoprotein cross-linked to collagen were about the same as that for phosphatidic acid liposomes and hydroxyapatite. This similarity in values indicates that the nucleation potential of these highly phosphorylated surfaces is about the same. It is concluded that phosphoproteins must be irreversibly bound to collagen fibrils for the mineralization of the collagen network in solutions that do not spontaneously precipitate. The phosphate esters of phosphoproteins are required for mineral induction, and the carboxylate groups are not sufficient.

  3. Enzymes of respiratory iron oxidation

    SciTech Connect

    Blake, R. II.

    1991-01-01

    This report focuses on the progress made in three areas of research concerned with enzymes involved in respiratory iron oxidation. The three areas are as follows: development of an improved procedure for the routine large scale culture of iron oxidizing chemolithotrophs based on the in-situ electrolysis of the soluble iron in the growth medium; to perform iron oxidation kinetic studies on whole cells using the oxygen electrode; and to identify, separate, purify, and characterize the individual cellular components.

  4. Kinetic approaches to lactose operon induction and bimodality.

    PubMed

    Michel, Denis

    2013-05-21

    The quasi-equilibrium approximation is acceptable when molecular interactions are fast enough compared to circuit dynamics, but is no longer allowed when cellular activities are governed by rare events. A typical example is the lactose operon (lac), one of the most famous paradigms of transcription regulation, for which several theories still coexist to describe its behaviors. The lac system is generally analyzed by using equilibrium constants, contradicting single-event hypotheses long suggested by Novick and Weiner (1957). Enzyme induction as an all-or-none phenomenon. Proc. Natl. Acad. Sci. USA 43, 553-566) and recently refined in the study of (Choi et al., 2008. A stochastic single-molecule event triggers phenotype switching of a bacterial cell. Science 322, 442-446). In the present report, a lac repressor (LacI)-mediated DNA immunoprecipitation experiment reveals that the natural LacI-lac DNA complex built in vivo is extremely tight and long-lived compared to the time scale of lac expression dynamics, which could functionally disconnect the abortive expression bursts and forbid using the standard modes of lac bistability. As alternatives, purely kinetic mechanisms are examined for their capacity to restrict induction through: (i) widely scattered derepression related to the arrival time variance of a predominantly backward asymmetric random walk and (ii) an induction threshold arising in a single window of derepression without recourse to nonlinear multimeric binding and Hill functions. Considering the complete disengagement of the lac repressor from the lac promoter as the probabilistic consequence of a transient stepwise mechanism, is sufficient to explain the sigmoidal lac responses as functions of time and of inducer concentration. This sigmoidal shape can be misleadingly interpreted as a phenomenon of equilibrium cooperativity classically used to explain bistability, but which has been reported to be weak in this system. PMID:23454080

  5. Self-powered enzyme micropumps

    NASA Astrophysics Data System (ADS)

    Sengupta, Samudra; Patra, Debabrata; Ortiz-Rivera, Isamar; Agrawal, Arjun; Shklyaev, Sergey; Dey, Krishna K.; Córdova-Figueroa, Ubaldo; Mallouk, Thomas E.; Sen, Ayusman

    2014-05-01

    Non-mechanical nano- and microscale pumps that function without the aid of an external power source and provide precise control over the flow rate in response to specific signals are needed for the development of new autonomous nano- and microscale systems. Here we show that surface-immobilized enzymes that are independent of adenosine triphosphate function as self-powered micropumps in the presence of their respective substrates. In the four cases studied (catalase, lipase, urease and glucose oxidase), the flow is driven by a gradient in fluid density generated by the enzymatic reaction. The pumping velocity increases with increasing substrate concentration and reaction rate. These rechargeable pumps can be triggered by the presence of specific analytes, which enables the design of enzyme-based devices that act both as sensor and pump. Finally, we show proof-of-concept enzyme-powered devices that autonomously deliver small molecules and proteins in response to specific chemical stimuli, including the release of insulin in response to glucose.

  6. Substrate Mediated Enzyme Prodrug Therapy

    PubMed Central

    Fejerskov, Betina; Zelikin, Alexander N.

    2012-01-01

    In this report, we detail Substrate Mediated Enzyme Prodrug Therapy (SMEPT) as a novel approach in drug delivery which relies on enzyme-functionalized cell culture substrates to achieve a localized conversion of benign prodrug(s) into active therapeutics with subsequent delivery to adhering cells or adjacent tissues. For proof-of-concept SMEPT, we use surface adhered micro-structured physical hydrogels based on poly(vinyl alcohol), β-glucuronidase enzyme and glucuronide prodrugs. We demonstrate enzymatic activity mediated by the assembled hydrogel samples and illustrate arms of control over rate of release of model fluorescent cargo. SMEPT was not impaired by adhering cells and afforded facile time - and dose – dependent uptake of the in situ generated fluorescent cargo by hepatic cells, HepG2. With the use of a glucuronide derivative of an anticancer drug, SN-38, SMEPT afforded a decrease in cell viability to a level similar to that achieved using parent drug. Finally, dose response was achieved using SMEPT and administration of judiciously chosen concentration of SN-38 glucuronide prodrug thus revealing external control over drug delivery using drug eluting surface. We believe that this highly adaptable concept will find use in diverse biomedical applications, specifically surface mediated drug delivery and tissue engineering. PMID:23152927

  7. Enzyme immunoassays in diagnostic medicine

    PubMed Central

    Voller, A.; Bidwell, D. E.; Bartlett, Ann

    1976-01-01

    Serological methods are playing an increasingly important role in the diagnosis and epidemiological assessment of diseases. Simple, inexpensive methods for large-scale application are urgently needed. The enzyme immunoassay methods developed recently and reviewed here hold great promise for application in a wide variety of conditions. Under laboratory conditions they can be as sensitive as radio-immunoassay, but they can also be adapted as simple field screening procedures. These methods are based on the use of antibodies or antigens that are linked to an insoluble carrier surface. This is then used to “capture” the relevant antigen or antibody in the test solution and the complex is detected by means of an enzyme-labelled antibody or antigen. The degradation of the enzyme substrate, measured photometrically, is proportional to the concentration of the unknown “antibody” or “antigen” in the test solution. The application of these techniques to endocrinology, immunopathology, haematology, microbiology, and parasitology is reviewed. PMID:1085667

  8. Cytochrome P450 enzyme mediated herbal drug interactions (Part 1)

    PubMed Central

    Wanwimolruk, Sompon; Prachayasittikul, Virapong

    2014-01-01

    It is well recognized that herbal supplements or herbal medicines are now commonly used. As many patients taking prescription medications are concomitantly using herbal supplements, there is considerable risk for adverse herbal drug interactions. Such interactions can enhance the risk for an individual patient, especially with regard to drugs with a narrow therapeutic index such as warfarin, cyclosporine A and digoxin. Herbal drug interactions can alter pharmacokinetic or/and pharmacodynamic properties of administered drugs. The most common pharmacokinetic interactions usually involve either the inhibition or induction of the metabolism of drugs catalyzed by the important enzymes, cytochrome P450 (CYP). The aim of the present article is to provide an updated review of clinically relevant metabolic CYP-mediated drug interactions between selected herbal supplements and prescription drugs. The commonly used herbal supplements selected include Echinacea, Ginkgo biloba, garlic, St. John's wort, goldenseal, and milk thistle. To date, several significant herbal drug interactions have their origins in the alteration of CYP enzyme activity by various phytochemicals. Numerous herbal drug interactions have been reported. Although the significance of many interactions is uncertain but several interactions, especially those with St. John’s wort, may have critical clinical consequences. St. John’s wort is a source of hyperforin, an active ingredient that has a strong affinity for the pregnane xenobiotic receptor (PXR). As a PXR ligand, hyperforin promotes expression of CYP3A4 enzymes in the small intestine and liver. This in turn causes induction of CYP3A4 and can reduce the oral bioavailability of many drugs making them less effective. The available evidence indicates that, at commonly recommended doses, other selected herbs including Echinacea, Ginkgo biloba, garlic, goldenseal and milk thistle do not act as potent or moderate inhibitors or inducers of CYP enzymes. A good

  9. 14 CFR 23.1101 - Induction air preheater design.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Induction air preheater design. 23.1101... Induction System § 23.1101 Induction air preheater design. Each exhaust-heated, induction air preheater must be designed and constructed to— (a) Ensure ventilation of the preheater when the induction...

  10. 14 CFR 23.1101 - Induction air preheater design.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Induction air preheater design. 23.1101... Induction System § 23.1101 Induction air preheater design. Each exhaust-heated, induction air preheater must be designed and constructed to— (a) Ensure ventilation of the preheater when the induction...

  11. 14 CFR 23.1101 - Induction air preheater design.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Induction air preheater design. 23.1101... Induction System § 23.1101 Induction air preheater design. Each exhaust-heated, induction air preheater must be designed and constructed to— (a) Ensure ventilation of the preheater when the induction...

  12. Designing Induction as Professional Learning Community

    ERIC Educational Resources Information Center

    O'Malley, Gary S.

    2010-01-01

    This study describes the professional development experience in one high school in which participants worked over a four-year period to share responsibility in the design of a teacher induction program. The article explores the salient features of an ideal induction program by examining purpose, organization, and delivery. The author concludes…

  13. Examining the Effects of New Teacher Induction

    ERIC Educational Resources Information Center

    Wechsler, Marjorie E.; Caspary, Kyra; Humphrey, Daniel C.; Matsko, Kavita Kapadia

    2012-01-01

    The objective of this research is to explore comprehensively the effect of induction on new teachers. Through a mixed-method design, the authors examine both the inputs of induction (i.e., the types of support provided for new teachers, its content, and frequency) and a variety of outcomes (i.e., teacher efficacy, teacher-reported growth, teacher…

  14. Math Activities that Encourage Inductive Thinking

    ERIC Educational Resources Information Center

    Freeman, Christopher

    2005-01-01

    There are two kinds of logical reasoning: "inductive" and "deductive". Inductive reasoning proceeds from effect back to cause, from special case to general principle. Detectives use it, examining the clues and conjecturing the actions that caused them. On the other hand, deductive reasoning proceeds from cause to effect, from principle to…

  15. Electromagnetic Induction Rediscovered Using Original Texts.

    ERIC Educational Resources Information Center

    Barth, Michael

    2000-01-01

    Describes a teaching unit on electromagnetic induction using historic texts. Uses some of Faraday's diary entries from 1831 to introduce the phenomenon of electromagnetic induction and teach about the properties of electricity, of taking conclusions from experiment, and scientific methodology. (ASK)

  16. Conceptual Influences on Category-Based Induction

    ERIC Educational Resources Information Center

    Gelman, Susan A.; Davidson, Natalie S.

    2013-01-01

    One important function of categories is to permit rich inductive inferences. Prior work shows that children use category labels to guide their inductive inferences. However, there are competing theories to explain this phenomenon, differing in the roles attributed to conceptual information vs. perceptual similarity. Seven experiments with 4- to…

  17. Empowering Beginning Teachers through Developmental Induction.

    ERIC Educational Resources Information Center

    Runyan, Charles Kent

    Empowering teacher induction programs are developmental in nature and generally have similar philosophical orientations. They identify and meet the instructional, non-instructional, and empowerment needs of novice teachers. Induction programs that empower include the following elements: development of personal strengths and ideas; defined…

  18. Induction: The Best Form of Professional Development.

    ERIC Educational Resources Information Center

    Wong, Harry K.

    2002-01-01

    Asserts that professional development for beginning teachers should begin with induction programs. Describes three exemplary beginning-teacher induction programs: Flowing Wells School District, Tucson, Arizona; Lafourche Parish Public Schools, Thibodaux, Louisiana; and Port Huron Area Schools, Port Huron, Michigan. (PKP)

  19. New-Teacher Induction 2.0

    ERIC Educational Resources Information Center

    Taranto, Greg

    2011-01-01

    The purpose of this program evaluation study was to design, implement, and evaluate the effectiveness of incorporating an online learning community as part of a comprehensive new-teacher induction program. The researcher, who serves as the middle school principal and new induction coordinator for the school district, used a mixed-method approach…

  20. The Tower of Hanoi and Inductive Logic

    ERIC Educational Resources Information Center

    Merrotsy, Peter

    2015-01-01

    In the "Australian Curriculum," the concept of mathematical induction is first met in the senior secondary subject Specialist Mathematics. This article details an example, the Tower of Hanoi problem, which provides an enactive introduction to the inductive process before moving to more abstract and cognitively demanding representations.…

  1. Blarina brevicauda as a biological monitor of polychlorinated biphenyls: Evaluation of hepatic cytochrome p450 induction

    USGS Publications Warehouse

    Russell, J.S.; Halbrook, R.S.; Woolf, A.; French, J.B., Jr.; Melancon, M.J.

    2004-01-01

    We assessed the value of short-tailed shrews (Blarina brevicauda) as a possible biomonitor for polychlorinated biphenyl pollution through measurement of the induction of hepatic cytochrome P450 and associated enzyme activities. First, we checked the inducibility of four monooxygenases (benzyloxyresorufin-O-dealkylase [BROD], ethoxyresorufin-O-dealkylase [EROD], methoxyresorufin-O-dealkylase [MROD], and pentoxyresorufin-O-dealkylase [PROD]) by measuring the activity of these enzymes in hepatic microsomes prepared from shrews injected with $-naphthoflavone ($NF) or phenobarbital (PB), typical inducers of cytochrome P4501A (CYP1A) and CYP2B enzyme families, respectively. Enzyme activity was induced in shrews that received $NF but not in shrews that received PB; PROD was not induced by either exposure. Later, shrews were exposed to a mixture of polychlorinated biphenyls (PCBs) (Aroclor 1242:1254, in 1:2 ratio) at 0.6, 9.6, and 150 ppm in food, for 31 d. Induction in these shrews was measured by specific enzyme activity (BROD, EROD, and MROD) in hepatic microsomes, by western blotting of solubilized microsomes against antibodies to CYP1A or CYP2B, and by duration of sodium pentobarbital-induced sleep. These three CYP enzymes were induced in shrews by PCBs at similar levels of exposure as in cotton rat (Sigmodon hispidus). Neither sleep time nor the amount of CYP2B family protein were affected by PCB exposure. Blarina brevicauda can be a useful biomonitor of PCBs that induce CYP1A, especially in habitats where they are the abundant small mammal.

  2. Blarina brevicauda as a biological monitor of polychlorinated biphenyls: evaluation of hepatic cytochrome P450 induction.

    PubMed

    Russell, Julie S; Halbrook, Richard S; Woolf, Alan; French, John B; Melancon, Mark J

    2004-08-01

    We assessed the value of short-tailed shrews (Blarina brevicauda) as a possible biomonitor for polychlorinated biphenyl pollution through measurement of the induction of hepatic cytochrome P450 and associated enzyme activities. First, we checked the inducibility of four monooxygenases (benzyloxyresorufin-O-dealkylase [BROD], ethoxyresorufin-O-dealkylase [EROD], methoxyresorufin-O-dealkylase [MROD], and pentoxyresorufin-O-dealkylase [PROD]) by measuring the activity of these enzymes in hepatic microsomes prepared from shrews injected with beta-naphthoflavone (betaNF) or phenobarbital (PB), typical inducers of cytochrome P4501A (CYP1A) and CYP2B enzyme families, respectively. Enzyme activity was induced in shrews that received betaNF but not in shrews that received PB; PROD was not induced by either exposure. Later, shrews were exposed to a mixture of polychlorinated biphenyls (PCBs) (Aroclor 1242:1254, in 1:2 ratio) at 0.6, 9.6, and 150 ppm in food, for 31 d. Induction in these shrews was measured by specific enzyme activity (BROD, EROD, and MROD) in hepatic microsomes, by western blotting of solubilized microsomes against antibodies to CYP1A or CYP2B, and by duration of sodium pentobarbital-induced sleep. These three CYP enzymes were induced in shrews by PCBs at similar levels of exposure as in cotton rat (Sigmodon hispidus). Neither sleep time nor the amount of CYP2B family protein were affected by PCB exposure. Blarina brevicauda can be a useful biomonitor of PCBs that induce CYP1A, especially in habitats where they are the abundant small mammal. PMID:15352474

  3. Evolutionary induction of sparse neural trees

    PubMed

    Zhang; Ohm; Muhlenbein

    1997-01-01

    This paper is concerned with the automatic induction of parsimonious neural networks. In contrast to other program induction situations, network induction entails parametric learning as well as structural adaptation. We present a novel representation scheme called neural trees that allows efficient learning of both network architectures and parameters by genetic search. A hybrid evolutionary method is developed for neural tree induction that combines genetic programming and the breeder genetic algorithm under the unified framework of the minimum description length principle. The method is successfully applied to the induction of higher order neural trees while still keeping the resulting structures sparse to ensure good generalization performance. Empirical results are provided on two chaotic time series prediction problems of practical interest. PMID:10021759

  4. Video luminescent barometry - The induction period

    NASA Technical Reports Server (NTRS)

    Uibel, Rory H.; Khalil, Gamal; Gouterman, Martin; Gallery, Jean; Callis, James B.

    1993-01-01

    Video monitoring of oxygen quenching of the photoluminescence of platinum octaethylporphyrin (PtOEP) in silicone polymer resin may be used to measure pressure distribution over an airfoil. A continuous increase of the luminescence intensity of PtOEP on exposure to the exciting light is known as the induction effect. The effect of several factors on PtOEP photoluminescence and the induction effect was investigated. The experimental apparatus is described and results are presented. It was observed that the relative induction amplitude and induction time increase at higher oxygen pressure and with thicker films. These observations may be explained if the singlet oxygen produced by oxygen quenching is consumed by the polymer and is therefore unavailable for further quenching. Researchers using this method for measuring pressure distribution on airfoil surfaces should be aware of the induction effect and its implications.

  5. Autophagy-Related Deubiquitinating Enzymes Involved in Health and Disease

    PubMed Central

    El Magraoui, Fouzi; Reidick, Christina; Meyer, Hemut E.; Platta, Harald W.

    2015-01-01

    Autophagy is an evolutionarily-conserved process that delivers diverse cytoplasmic components to the lysosomal compartment for either recycling or degradation. This involves the removal of protein aggregates, the turnover of organelles, as well as the elimination of intracellular pathogens. In this situation, when only specific cargoes should be targeted to the lysosome, the potential targets can be selectively marked by the attachment of ubiquitin in order to be recognized by autophagy-receptors. Ubiquitination plays a central role in this process, because it regulates early signaling events during the induction of autophagy and is also used as a degradation-tag on the potential autophagic cargo protein. Here, we review how the ubiquitin-dependent steps of autophagy are balanced or counteracted by deubiquitination events. Moreover, we highlight the functional role of the corresponding deubiquitinating enzymes and discuss how they might be involved in the occurrence of cancer, neurodegenerative diseases or infection with pathogenic bacteria. PMID:26445063

  6. A new strategy for intracellular delivery of enzyme using mesoporous silica nanoparticles: superoxide dismutase.

    PubMed

    Chen, Yi-Ping; Chen, Chien-Tsu; Hung, Yann; Chou, Chih-Ming; Liu, Tsang-Pai; Liang, Ming-Ren; Chen, Chao-Tsen; Mou, Chung-Yuan

    2013-01-30

    We developed mesoporous silica nanoparticle (MSN) as a multifunctional vehicle for enzyme delivery. Enhanced transmembrane delivery of a superoxide dismutase (SOD) enzyme embedded in MSN was demonstrated. Conjugation of the cell-penetrating peptide derived from the human immunodeficiency virus 1 (HIV) transactivator protein (TAT) to mesoporous silica nanoparticle is shown to be an effective way to enhance transmembrane delivery of nanoparticles for intracellular and molecular therapy. Cu,Zn-superoxide dismutase (SOD) is a key antioxidant enzyme that detoxifies intracellular reactive oxygen species, ROS, thereby protecting cells from oxidative damage. In this study, we fused a human Cu,Zn-SOD gene with TAT in a bacterial expression vector to produce a genetic in-frame His-tagged TAT-SOD fusion protein. The His-tagged TAT-SOD fusion protein was expressed in E. coli using IPTG induction and purified using FMSN-Ni-NTA. The purified TAT-SOD was conjugated to FITC-MSN forming FMSN-TAT-SOD. The effectiveness of FMSN-TAT-SOD as an agent against ROS was investigated, which included the level of ROS and apoptosis after free radicals induction and functional recovery after ROS damage. Confocal microscopy on live unfixed cells and flow cytometry analysis showed characteristic nonendosomal distribution of FMSN-TAT-SOD. Results suggested that FMSN-TAT-SOD may provide a strategy for the therapeutic delivery of antioxidant enzymes that protect cells from ROS damage. PMID:23289802

  7. Laboratory and field studies on biotransformation enzymes in sunfish (Lepomis sp. )

    SciTech Connect

    Jimenez, B.D.; Oikari, A.; Adams, S.M.; Esau, B.D.; Morrissey, C.M.; Petanen, T.I. )

    1988-09-01

    To cope with pollutants, organisms synthesize enzymes that detoxify organic compounds (mixed function oxidases or MFOs). A series of these enzymes are presently being employed as indicators of pollution at Oak Ridge National laboratory in the Y-12 Biological Monitoring and Abatement Program. The quantities and activities of several hepatic enzymes, as well as the liver somatic indices, were measured in redbreast sunfish, Leopomis auritus, sampled from several stations along a stream receiving large inputs of industrial and municipal effluents and a stream in a non-industrialized, rural drainage area. Fish collected close to the industrial and municipal outfalls exhibited high quantities and activities of these enzymes, as well as elevated somatic indices, compared to those from the rural stream and from other locations along the polluted stream. Laboratory experiments were conducted using Bluegill-green sunfish hybrid which were exposed to approximately 0.5 g Benzo(a)pyrene (BaP) per liter under 24 h static renewal conditions. The time course of induction for MFO activity was obtained. Induction of MFO activity occurred a week after BaP exposure.

  8. Extracellular enzyme kinetics scale with resource availability

    EPA Science Inventory

    Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimi...

  9. Enzymes toughen up for chemical processing

    SciTech Connect

    Hairston, D.

    1995-05-01

    While enzymes have been making tremendous inroads into detergent formulation and food processing, the penetration of these protein-based catalysts into other chemical-process manufacture and hazardous waste treatment--where they are slated to replace heavy metal catalysts and other processing aids--has been relatively slow. Recently, however, enhancements in the enzyme`s properties are opening the door wider for such broadened usage. Some of these non-traditional uses of enzymes are described.

  10. Control of glycolytic enzyme binding: effect of changing enzyme substrate concentrations on in vivo enzyme distributions.

    PubMed

    Brooks, S P; Storey, K B

    1993-05-12

    The effect of changing concentrations of glycolytic intermediates on the binding of phosphofructokinase, aldolase and pyruvate kinase to cellular particulate matter was investigated. Concentrations of glycolytic intermediates were altered by adding 2 mM iodoacetic acid (IAA) to an incubation medium containing tissues isolated from the channelled whelk Busycon canaliculatum. Iodoacetic acid inhibited glyceraldehyde 3-phosphate dehydrogenase activity causing a 100-400 fold increase in the concentration of fructose 1,6-bisphosphate as well as 3-20 fold increases in glucose 6-phosphate, fructose 6-phosphate, and dihydroxyacetone phosphate levels depending on the experimental protocol. Cellular pH values were not statistically different in the presence of IAA. Measurement of enzyme binding to particulate matter showed that the binding of phosphofructokinase, aldolase and pyruvate kinase was unaffected by iodoacetic acid under any experimental condition. These results show that changes in the tissue concentrations of enzyme substrates and products do not regulate enzyme binding to particulate matter in the cell. PMID:8350861

  11. Xylanolytic enzyme systems in Arthrobacter sp. MTCC 5214 and Lactobacillus sp.

    PubMed

    Khandeparker, Rakhee; Jalal, Thasneem

    2015-01-01

    The production of extracellular xylanolytic enzymes such as xylanase, α-l-arabinofuranosidase (α-l-AFase), and acetyl xylan esterase (Axe) by marine Arthrobacter sp. and Lactobacillus sp. was investigated using different carbon sources. Induction and repression of all these enzymes differed with carbon source and also with the organism. Wheat bran was the best carbon source for the production of xylanase and α-l-AFase, whereas both isolates showed maximum Axe production when grown on oat bran as a carbon source. Preferential utilization of a carbon source for enzyme production can give us better insights into regulatory mechanism in these marine bacteria. Elution profile as well as zymogram analysis indicated the possibility of bifunctional α-l-AFase-Axes in both marine bacteria. PMID:24888562

  12. Role of nitrate and nitrite in the induction of nitrite reductase in leaves of barley seedlings

    NASA Technical Reports Server (NTRS)

    Aslam, M.; Huffaker, R. C.

    1989-01-01

    The role of NO3- and NO2- in the induction of nitrite reductase (NiR) activity in detached leaves of 8-day-old barley (Hordeum vulgare L.) seedlings was investigated. Barley leaves contained 6 to 8 micromoles NO2-/gram fresh weight x hour of endogenous NiR activity when grown in N-free solutions. Supply of both NO2- and NO3- induced the enzyme activity above the endogenous levels (5 and 10 times, respectively at 10 millimolar NO2- and NO3- over a 24 hour period). In NO3(-)-supplied leaves, NiR induction occurred at an ambient NO3- concentration of as low as 0.05 millimolar; however, no NiR induction was found in leaves supplied with NO2- until the ambient NO2- concentration was 0.5 millimolar. Nitrate accumulated in NO2(-)-fed leaves. The amount of NO3- accumulating in NO2(-)-fed leaves induced similar levels of NiR as did equivalent amounts of NO3- accumulating in NO3(-)-fed leaves. Induction of NiR in NO2(-)-fed leaves was not seen until NO3- was detectable (30 nanomoles/gram fresh weight) in the leaves. The internal concentrations of NO3-, irrespective of N source, were highly correlated with the levels of NiR induced. When the reduction of NO3- to NO2- was inhibited by WO4(2-), the induction of NiR was inhibited only partially. The results indicate that in barley leaves in NiR is induced by NO3- directly, i.e. without being reduced to NO2-, and that absorbed NO2- induces the enzyme activity indirectly after being oxidized to NO3- within the leaf.

  13. Digestive Enzyme Supplementation in Gastrointestinal Diseases

    PubMed Central

    Ianiro, Gianluca; Pecere, Silvia; Giorgio, Valentina; Gasbarrini, Antonio; Cammarota, Giovanni

    2016-01-01

    Background: Digestive enzymes are able to break down proteins and carbohydrates and lipids, and their supplementation may play a role in the management of digestive disorders, from lactose intolerance to cystic fibrosis. To date, several formulations of digestive enzymes are available on the market, being different each other in terms of enzyme type, source and origin, and dosage. Methods: This review, performed through a non-systematic search of the available literature, will provide an overview of the current knowledge of digestive enzyme supplementation in gastrointestinal disorders, discussion of the use of pancreatic enzymes, lactase (β-galactosidase) and conjugated bile acids, and also exploring the future perspective of digestive enzyme supplementation. Results: Currently, the animal-derived enzymes represent an established standard of care, however the growing study of plant-based and microbe-derived enzymes offers great promise in the advancement of digestive enzyme therapy. Conclusion: New frontiers of enzyme replacement are being evaluated also in the treatment of diseases not specifically related to enzyme deficiency, whereas the combination of different enzymes might constitute an intriguing therapeutic option in the future. PMID:26806042

  14. The ENZYME data bank in 1995.

    PubMed Central

    Bairoch, A

    1996-01-01

    The ENZYME data bank is a repository of information relative to the nomenclature of enzymes. The current version (October 1995) contains information relevant to 3594 enzymes. It is available from a variety of file and ftp servers as well as through the ExPASy World Wide Web server (http://expasy.hcuge.ch/). PMID:8594586

  15. Determining Enzyme Activity by Radial Diffusion

    ERIC Educational Resources Information Center

    Davis, Bill D.

    1977-01-01

    Discusses advantages of radial diffusion assay in determining presence of enzyme and/or rough approximation of amount of enzyme activities. Procedures are included for the preparation of starch-agar plates, and the application and determination of enzyme. Techniques using plant materials (homogenates, tissues, ungerminated embryos, and seedlings)…

  16. Microorganisms detected by enzyme-catalyzed reaction

    NASA Technical Reports Server (NTRS)

    Vango, S. P.; Weetall, H. H.; Weliky, N.

    1966-01-01

    Enzymes detect the presence of microorganisms in soils. The enzyme lysozymi is used to release the enzyme catalase from the microorganisms in a soil sample. The catalase catalyzes the decomposition of added hydrogen peroxide to produce oxygen which is detected manometrically. The partial pressure of the oxygen serves as an index of the samples bacteria content.

  17. 21 CFR 864.4400 - Enzyme preparations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Enzyme preparations. 864.4400 Section 864.4400...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are used in the...

  18. 21 CFR 864.4400 - Enzyme preparations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Enzyme preparations. 864.4400 Section 864.4400...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are used in the...

  19. 21 CFR 864.4400 - Enzyme preparations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Enzyme preparations. 864.4400 Section 864.4400...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are used in the...

  20. 21 CFR 864.4400 - Enzyme preparations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Enzyme preparations. 864.4400 Section 864.4400...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are used in the...

  1. 21 CFR 864.4400 - Enzyme preparations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Enzyme preparations. 864.4400 Section 864.4400...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are used in the...

  2. Immobilization of Enzymes in Polymer Supports.

    ERIC Educational Resources Information Center

    Conlon, Hugh D.; Walt, David R.

    1986-01-01

    Two experiments in which an enzyme is immobilized onto a polymeric support are described. The experiments (which also demonstrate two different polymer preparations) involve: (1) entrapping an enzyme in an acrylamide polymer; and (2) reacting the amino groups on the enzyme's (esterase) lysine residues with an activated polymer. (JN)

  3. The ENZYME data bank in 1999.

    PubMed Central

    Bairoch, A

    1999-01-01

    The ENZYME data bank is a repository of information related to the nomenclature of enzymes. In recent years it has become an indispensable resource for the development of metabolic databases. The current version contains information on 3704 enzymes. It is available through the ExPASy WWW server (http://www.expasy.ch/). PMID:9847212

  4. Screening of Enzyme Biomarker for Nanotoxicity of Zinc Oxide in OREOCHROMIS MOSSAMBICUS

    NASA Astrophysics Data System (ADS)

    Subramanian, Periasamy; Bupesh, Giridharan

    2011-06-01

    Experiments were conducted to determine the effects of Zinc oxide (ZnO) nanoparticles (NPs) on fish models. Oreochromis mossambicus was orally administered with ZnO NPs (50-100 nm) once and its effects at five different concentrations (60 ppm-100 ppm) were observed for 12 days. Enzymatic assays were performed at every three days interval in the vital tissues of liver, gill, muscle and kidney. The defense enzymes, ethoxyresorufin O-deethylase (EROD) and glutathione S transferase (GST) exerted a dose dependent elevation up to 6 days. This hike then declines in higher concentrations and extended duration. Whereas the tissue damaging enzymes, glutamate oxaloacetic transaminase (GOT), glutamate pyruvic transaminase (GPT) and alkaline phosphatase (ALP) as well as the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) exhibited a dose and duration dependent increase until the end of the experiment. Among these enzymes, the antioxidant enzymes response to ZnO NP toxicity on fish showed notable continuous induction. This study demonstrates that antioxidant enzymes responses in O. mossambicus could be used as a biomarker for the early detection of nanotoxicity.

  5. Zeaxanthin induces Nrf2-mediated phase II enzymes in protection of cell death.

    PubMed

    Zou, X; Gao, J; Zheng, Y; Wang, X; Chen, C; Cao, K; Xu, J; Li, Y; Lu, W; Liu, J; Feng, Z

    2014-01-01

    Zeaxanthin (Zea) is a major carotenoid pigment contained in human retina, and its daily supplementation associated with lower risk of age-related macular degeneration. Despite known property of Zea as an antioxidant, its underlying molecular mechanisms of action remain poorly understood. In this study, we aim to study the regulation mechanism of Zea on phase II detoxification enzymes. In normal human retinal pigment epithelium cells, Zea promoted the nuclear translocation of NF-E2-related factor 2 (Nrf2) and induced mRNA and protein expression of phase II enzymes, the induction was suppressed by specific knockdown of Nrf2. Zea also effectively protected against tert-butyl hydroperoxide-induced mitochondrial dysfunction and apoptosis. Glutathione (GSH) as the most important antioxidant was also induced by Zea through Nrf2 activation in a time- and dose-dependent manner, whereas the protective effects of Zea were decimated by inhibition of GSH synthesis. Finally, Zea activated the PI3K/Akt and MAPK/ERK pathway, whereas only PI3K/Akt activation correlated with phase II enzymes induction and Zea protection. In further in vivo analyses, Zea showed effects of inducing phase II enzymes and increased GSH content, which contributed to the reduced lipid and protein peroxidation in the retina as well as the liver, heart, and serum of the Sprague-Dawley rats. For the first time, Zea is presented as a phase II enzymes inducer instead of being an antioxidant. By activating Nrf2-mediated phase II enzymes, Zea could enhance anti-oxidative capacity and prevent cell death both in vivo and in vitro. PMID:24810054

  6. [Muscle enzyme activity and exercise].

    PubMed

    Gojanovic, B; Feihl, F; Gremion, G; Waeber, B

    2009-02-01

    Exercise is classically associated with muscular soreness, presenting one to two days later, delayed onset muscular soreness. Blood muscle enzymes and protein elevations are characteristic, and may cause renal failure. Creatin phosphokinase peak appears on the fourth day and depends on exercise type and individual parameters. This effect is attenuated with repeated bouts, by habituation. Metabolic complications are rare. The knowledge of this reaction, even with common exercises, allows to postpone investigations for a complex metabolic disorder, or to avoid stopping a medication for fear of a side effect, as with statins. Indeed, it is necessary to wait for seven days without any exercise before interpreting an elevated CK result. PMID:19180440

  7. Two frameworks for integrating knowledge in induction

    NASA Technical Reports Server (NTRS)

    Rosenbloom, Paul S.; Hirsh, Haym; Cohen, William W.; Smith, Benjamin D.

    1994-01-01

    The use of knowledge in inductive learning is critical for improving the quality of the concept definitions generated, reducing the number of examples required in order to learn effective concept definitions, and reducing the computation needed to find good concept definitions. Relevant knowledge may come in many forms (such as examples, descriptions, advice, and constraints) and from many sources (such as books, teachers, databases, and scientific instruments). How to extract the relevant knowledge from this plethora of possibilities, and then to integrate it together so as to appropriately affect the induction process is perhaps the key issue at this point in inductive learning. Here the focus is on the integration part of this problem; that is, how induction algorithms can, and do, utilize a range of extracted knowledge. Preliminary work on a transformational framework for defining knowledge-intensive inductive algorithms out of relatively knowledge-free algorithms is described, as is a more tentative problems-space framework that attempts to cover all induction algorithms within a single general approach. These frameworks help to organize what is known about current knowledge-intensive induction algorithms, and to point towards new algorithms.

  8. An induction linac developed for FEL application

    NASA Astrophysics Data System (ADS)

    de Mascureau, J.; Anthouard, Ph.; Bardy, J.; Eyharts, Ph.; Eyl, P.; Launspach, J.; Thevenot, M.; Villate, D.

    1992-07-01

    An induction linac is being studied and built at CESTA for FEL application. At first we studied the induction technology and namely the high-voltage (HV) generators and the induction cells. A HV generator designed to feed the cells with calibrated pulses (150 kV, 50 ns, δV/V < 1%) has been built using a resonant charging system and magnetic switches. This generator is planned for kHz repetition-rate operation. A prototype induction cell has also been built and tested with a cable generator. An electron injector (1.5 MeV, 1.5kA) has been designed and is now under test: it uses ten induction cells and a thermionic dispenser cathode. Numerical codes have been developed and simulations have been compared with experimental results for HV generators, induction cells, and the injector. An induction accelerating module has been studied and we plan to have the accelerator working at 3 MeV in 1992.

  9. Inductive cooling in quantum magnetomechanics

    NASA Astrophysics Data System (ADS)

    Romero-Sanchez, Erick; Twamley, Jason; Bowen, Warwick P.; Vanner, Michael R.

    Coupling to light or microwave fields allows quantum control of the motion of a mechanical oscillator, and offers prospects for precision sensing, quantum information systems, and tests of fundamental physics. In cavity electromechanics ground state cooling has been achieved using resolved sideband cooling. Here we present an alternative approach based on a magnetomechanical system that inductively couples an LC resonator to a mechanical oscillator. The experimental setup consists of a micro cantilever with a pyramidal magnetic tip attached at the end of the beam. The sharp end of the magnetic tip is positioned close to the planar microfabricated inductor of the LC resonator. The displacement in the position of the end of the cantilever generates a change in flux through the coil inducing an electromotive force in the circuit. The current in the LC resonator generates a magnetic field, and then a force between the tip and the coil. When they are strongly coupled and the mechanical resonance frequency ωm exceeds the electrical decay rate of the resonator γe, resolved sideband cooling can be used to cool the mechanics. We present estimations for the coupling rates and the experimental parameters required for these experiments. E. Romero acknowledges to CONACyT.

  10. Enzyme Analysis to Determine Glucose Content

    NASA Astrophysics Data System (ADS)

    Carpenter, Charles; Ward, Robert E.

    Enzyme analysis is used for many purposes in food science and technology. Enzyme activity is used to indicate adequate processing, to assess enzyme preparations, and to measure constituents of foods that are enzyme substrates. In this experiment, the glucose content of corn syrup solids is determined using the enzymes, glucose oxidase and peroxidase. Glucose oxidase catalyzes the oxidation of glucose to form hydrogen peroxide (H2O2), which then reacts with a dye in the presence of peroxidase to give a stable colored product.

  11. Stabilization of enzymes through encapsulation in liposomes.

    PubMed

    Yoshimoto, Makoto

    2011-01-01

    Phospholipid vesicle (liposome) offers an aqueous compartment surrounded by lipid bilayer membranes. Various enzyme molecules were reported to be encapsulated in liposomes. The liposomal enzyme shows peculiar catalytic activity and selectivity to the substrate in the bulk liquid, which are predominantly derived from the substrate permeation resistance through the membrane. We reported that the quaternary structure of bovine liver catalase and alcohol dehydrogenase was stabilized in liposomes through their interaction with lipid membranes. The method and condition for preparing the enzyme-containing liposomes with well-defined size, lipid composition, and enzyme content are of particular importance, because these properties dominate the catalytic performance and stability of the liposomal enzymes. PMID:20865384

  12. [The synthesis of specific enzyme inhibitors].

    PubMed

    Iakovleva, G M

    1987-04-01

    The review deals with directed synthesis of specific enzyme inhibitors. They are classified within the framework of the mechanistic approach, namely, stable analogues of substrates, which form enzyme complexes mimicking the Michaelis complex or those which influence the chemical stages of enzyme catalysis; conformational inhibitors; substrate analogues participating in enzyme reactions and producing modified products; suicide inhibitors; stage inhibitors (inhibitors influencing certain stages of enzyme reaction); transition state analogues; multisubstrate analogues and collected substrates. Types of chemical modification used in synthesis of the specific inhibitors are discussed. Some possibilities of the quantity structure-activity relationship methods, computer modelling and molecular graphics in designing the optimal structure of inhibitors are mentioned. PMID:3300658

  13. Ion plating with an induction heating source

    NASA Technical Reports Server (NTRS)

    Spalvins, T.; Brainard, W. A.

    1976-01-01

    Induction heating is introduced as an evaporation heat source in ion plating. A bare induction coil without shielding can be directly used in the glow discharge region with no arcing. The only requirement is to utilize an rf inductive generator with low operating frequency of 75 kHz. Mechanical simplicity of the ion plating apparatus and ease of operation is a great asset for industrial applications; practically any metal such as nickel, iron, and the high temperature refractories can be evaporated and ion plated.

  14. A Long Pulse Solid State Induction Modulator

    SciTech Connect

    Cassel, R

    2004-05-04

    The Next Linear Collider accelerator is developing a high efficiency, highly reliable, and low cost pulsed-power modulator to drive the NLC 500KV, 230A X band klystrons. The induction of fractional turn transformer is most applicable for short pulse width of less than 1.5 microseconds due to the size of the induction cores involved. This paper will cover the techniques SLAC is developing to use the induction modulator in longer pulse operation of up to 15 microseconds. The 3 microseconds SLAC design as will, as the proposals for wider pulse application will be discussed.

  15. Standardizing criteria for scheduling elective labor inductions.

    PubMed

    Durham, Laurel; Veltman, Larry; Davis, Peggy; Ferguson, Linda; Hacker, Margaret; Hooker, Debra; Larison, Kristine; Pribyl, Jennifer; Twilleager, Karen; Van Hout, Gretchen

    2008-01-01

    Induction of labor has become routine practice in perinatal units across the United States, with rates reaching a high of 21.2% of births in 2003-2004. This article describes the process our institution used to standardize the criteria for scheduling inductions. Specifically, we aimed to increase the consistency in practice for scheduling and performing elective inductions, including mandating gestational age of 39 completed weeks, ensuring cervical ripeness, and disallowing the use of cervical ripening agents. The nurses' participation, from planning to implementation, was critical in the success of this evidence-based practice change. PMID:18453906

  16. Smart mud and sensitive enzymes

    SciTech Connect

    Knott, D.

    1993-04-19

    Environmental legislation is increasingly preventing use of oil base mud. Most recently, Marathon Oil U.K. Ltd. won a U.K. production license that specified oil base mud cannot be used on the license blocks. The goal is to protect sea-birds. Unfortunately, water base mud, the green' alternative, does not have a performance to match oil base mud. But an Aberdeen chemist thinks he has found the answer with Smart Mud, an emulsion drilling mud that becomes water soluble as soon as it hits the sea. Smart Mud passed the laboratory test stage and is ready for field trials this year. Another researcher is using enzymes and organisms to detect gases that are hard to monitor and cause problems for the oil and gas industry: phenol vapors, methane, and sulfur and nitrous oxides. The methane sensor, for example, uses methanotrophic organisms. They metabolize methane, producing chemicals that can be detected by electrochemical sensors, which relay signals to instruments. Enzymes perform a similar task for phenol and oxide detection. The main problem is to keep the biosensors alive and detect their by-products, while maintaining contact with the toxic gases. To do this, the team invented a polymer matrix in which the biosensors can live.

  17. Enzyme extraction by ultrasound from sludge flocs.

    PubMed

    Yu, Guanghui; He, Pinjing; Shao, Liming; Zhu, Yishu

    2009-01-01

    Enzymes play essential roles in the biological processes of sludge treatment. In this article, the ultrasound method to extract enzymes from sludge flocs was presented. Results showed that using ultrasound method at 20 kHz could extract more types of enzymes than that at 40 kHz and ethylenediamine tetraacetic acid (EDTA) methods. The optimum parameters of ultrasound extraction at 20 kHz were duration of 10 min and intensity of 552 W/g TSS. Under the optimum condition, ultrasound could break the cells and extract both the extracellular and a small part of intercellular enzymes. Ultrasound intensity was apparently more susceptive to enzyme extraction than duration, suggesting that the control of intensity during ultrasound extraction was more important than that of duration. The Pearson correlation analysis between enzyme activities and cation contents revealed that the different types of enzymes had distinct cation binding characteristics. PMID:19402423

  18. Virulence-Associated Enzymes of Cryptococcus neoformans

    PubMed Central

    Almeida, Fausto; Wolf, Julie M.

    2015-01-01

    Enzymes play key roles in fungal pathogenesis. Manipulation of enzyme expression or activity can significantly alter the infection process, and enzyme expression profiles can be a hallmark of disease. Hence, enzymes are worthy targets for better understanding pathogenesis and identifying new options for combatting fungal infections. Advances in genomics, proteomics, transcriptomics, and mass spectrometry have enabled the identification and characterization of new fungal enzymes. This review focuses on recent developments in the virulence-associated enzymes from Cryptococcus neoformans. The enzymatic suite of C. neoformans has evolved for environmental survival, but several of these enzymes play a dual role in colonizing the mammalian host. We also discuss new therapeutic and diagnostic strategies that could be based on the underlying enzymology. PMID:26453651

  19. Enzymes related to fructose utilization in Pseudomonas cepacia.

    PubMed

    Allenza, P; Lee, Y N; Lessie, T G

    1982-06-01

    Growth of Pseudomonas cepacia on fructose, mannitol, or sorbitol depended on formation of an inducible fructokinase (forming fructose-6-phosphate) and the presence of enzymes of the Entner-Doudoroff pathway. Mutants deficient in any of these enzymes failed to utilize the aforementioned carbohydrates. Fructokinase deficiency did not affect growth of the bacteria on glucose. Fructose was accumulated intracellularly by active transport. Mutants blocked in transport of fructose grew normally on mannitol or sorbitol despite their inability to utilize fructose. Growth on either of these hexitols or on galactitol was accompanied by induction of two hexitol dehydrogenases, one active primarily with mannitol and the other active with sorbitol and galactitol. As expected, a mutant deficient in mannitol dehydrogenase failed to utilize mannitol as a carbon and energy source but grew normally on sorbitol and galactitol. Extracts of bacteria grown on fructose, mannitol, or sorbitol and higher levels of phosphoglucose isomerase than extracts of bacteria grown on alternate carbon sources such as citrate or phthalate. The higher levels were due to appearance of a second phosphoglucose isomerase species not present in cells with the lower activity. The results indicate that the initial steps in fructose utilization by P. cepacia differ from those of most other pseudomonads, which transport fructose by phosphoenolpyruvate-dependent translocation, forming fructose-1-phosphate, and suggest that degradation of fructose, mannitol, and sorbitol occurs primarily via the Entner-Doudoroff pathway. PMID:6281243

  20. Regulation of antioxidant enzymes in lung after oxidant injury.

    PubMed Central

    Quinlan, T; Spivack, S; Mossman, B T

    1994-01-01

    Studies have implicated active oxygen species (AOS) in the pathogenesis of various lung diseases. Many chemical and physical agents in the environment are potent generators of AOS, including ozone, hyperoxia, mineral dusts, paraquat, etc. These agents produce AOS by different mechanisms, but frequently the lung is the primary target of toxicity, and exposure results in damage to lung tissue to varying degrees. The lung has developed defenses to AOS-mediated damage, which include antioxidant enzymes, the superoxide dismutases [copper-zinc (CuZnSOD) and manganese-containing (MnSOD)], catalase, and glutathione peroxidase (GPX). In this review, antioxidant defenses to environmental stresses in the lung as well as in isolated pulmonary cells following exposure to a number of different oxidants, are summarized. Each oxidant appears to induce a different pattern of antioxidant enzyme response in the lung, although some common trends, i.e., induction of MnSOD following oxidants inducing inflammation or pulmonary fibrosis, in responses to oxidants occur. Responses may vary between the different cell types in the lung as a function of cell-cycle or other factors. Increases in MnSOD mRNA or immunoreactive protein in response to certain oxidants may serve as a biomarker of AOS-mediated damage in the lung. Images Figure 3. PMID:7523104

  1. Induction of Crassulacean Acid Metabolism in the Facultative Halophyte Mesembryanthemum crystallinum by Abscisic Acid 1

    PubMed Central

    Chu, Chun; Dai, Ziyu; Ku, Maurice S. B.; Edwards, Gerald E.

    1990-01-01

    The facultative halophyte, Mesembryanthemum crystallinum, shifts its mode of carbon assimilation from the C3 pathway to Crassulacean acid metabolism (CAM) in response to water stress. In this study, exogenously applied abscisic acid (ABA), at micromolar concentrations, could partially substitute for water stress in induction of CAM in this species. ABA at concentrations of 5 to 10 micromolar, when applied to leaves or to the roots in hydroponic culture or in soil, induced the expression of CAM within days (as indicated by the nocturnal accumulation of total titratable acidity and malate). After applying ABA there was also an increase in phosphoenolpyruvate carboxylase and NADP-malic enzyme activities. The degree and time course of induction by ABA were comparable to those induced by salt and water stress. Electrophoretic analyses of leaf soluble protein indicate that the increases in phosphoenolpyruvate carboxylase activity during the induction by ABA, salt, and water stress are due to an increase in the quantity of the enzyme protein. ABA may be a factor in the stress-induced expression of CAM in M. crystallinum, serving as a functional link between stress and biochemical adaptation. Images Figure 9 PMID:16667587

  2. Inductive Methodology and a Research Team.

    ERIC Educational Resources Information Center

    Cohen, Marlene Zichi; And Others

    1991-01-01

    Large teams of researchers using inductive methodologies are relatively rare and present unique challenges to team members. A team from the University of Iowa reports on what it experienced during a project to develop a taxonomy of nursing interventions. (JOW)

  3. Parthenogenesis induction by Wolbachia in parasitoids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The maternally inherited intracellular bacterium, Wolbachia pipientis, induces reproductive alterations in host arthropod populations such as male-killing, feminization, parthenogenesis induction (PI, or reproduction without males) and cytoplasmic incompatibility. Here we report that PI in Mexican O...

  4. Coreless Concept for High Gradient Induction Cell

    SciTech Connect

    Krasnykh, Anatoly; /SLAC

    2008-01-07

    An induction linac cell for a high gradient is discussed. The proposed solid state coreless approach for the induction linac topology (SLIM{reg_sign}) is based on nanosecond mode operation. This mode may have an acceleration gradient comparable with gradients of rf- accelerator structures. The discussed induction system has the high electric efficiency. The key elements are a solid state semiconductor switch and a high electric density dielectric with a thin section length. The energy in the induction system is storied in the magnetic field. The nanosecond current break-up produces the high voltage. The induced voltage is used for acceleration. This manner of an operation allows the use of low voltage elements in the booster part and achieves a high accelerating gradient. The proposed topology was tested in POP (proof of principle) experiments.

  5. MPD thruster operation with inductively stored energy

    NASA Technical Reports Server (NTRS)

    Clark, K. E.; Von Jaskowsky, W. F.; Wolff, M.; Budd, D. W.

    1979-01-01

    Magnetoplasmadynamic (MPD) thrusters with 10-cm and 2.5-cm long thoriated tungsten cathodes have been operated with both inductive and capacitive energy sources at currents up to 8 kA. Voltage-current characteristics and magnetic field measurements show that over most of the operating range, the inductively driven thruster acts as a continuously varying quasi-steady accelerator at the same current. However, at values of a specified parameter near the onset condition for voltage fluctuations and electrode and insulator erosion, the voltage for the inductively driven thruster is higher than its quasi-steady counterpart. This higher voltage occurs because the equilibration time constant of the MPD discharge, is too large to allow the terminal voltage to attain a quasi-steady value as the inductively driven current decreases.

  6. Laser ablation inductively coupled plasma mass spectrometry

    SciTech Connect

    Durrant, S.F.

    1996-07-01

    Laser ablation for solid sample introduction to inductively coupled plasma mass spectrometry for bulk and spatially-resolved elemental analysis is briefly reviewed. {copyright} {ital 1996 American Institute of Physics.}

  7. Development of inductive generalization with familiar categories.

    PubMed

    Fisher, Anna V; Godwin, Karrie E; Matlen, Bryan J

    2015-10-01

    Inductive generalization is ubiquitous in human cognition. In the developmental literature, two different theoretical accounts of this important process have been proposed: a naïve theory account and a similarity-based account. However, a number of recent findings cannot be explained within the existing theoretical accounts. We describe a revised version of the similarity-based account of inductive generalization with familiar categories. We tested the novel predictions of this account in two reported studies with 4-year-old children (N = 57). The reported studies include the first short-term longitudinal investigation of the development of children's induction with familiar categories, and it is the first study to explore the role of individual differences in semantic organization, general intelligence, working memory, and inhibition in children's induction. PMID:25737367

  8. Inductive tuners for microwave driven discharge lamps

    DOEpatents

    Simpson, James E.

    1999-01-01

    An RF powered electrodeless lamp utilizing an inductive tuner in the waveguide which couples the RF power to the lamp cavity, for reducing reflected RF power and causing the lamp to operate efficiently.

  9. Inductive tuners for microwave driven discharge lamps

    SciTech Connect

    Simpson, J.E.

    1999-11-02

    An RF powered electrodeless lamp utilizing an inductive tuner in the waveguide which couples the RF power to the lamp cavity, for reducing reflected RF power and causing the lamp to operate efficiently.

  10. Effects of cadmium exposure on digestive enzymes, antioxidant enzymes, and lipid peroxidation in the freshwater crab Sinopotamon henanense.

    PubMed

    Wu, Hao; Xuan, Ruijing; Li, Yingjun; Zhang, Xiaomin; Wang, Qian; Wang, Lan

    2013-06-01

    In this study, the effects of cadmium (Cd) stress on the activities of disaccharidases (sucrase, lactase, and maltase), amylase, trypsin, pepsase, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) content in the alimentary system of freshwater crabs Sinopotamon henanense were studied. Results showed that the enzyme activities in the stomach, intestine, and hepatopancreas changed with Cd concentration. In terms of digestive enzymes, Cd exposure had an inhibitory effect on the activities of the disaccharidases, amylase, and pepsase (only in the stomach). Significant induction of trypsin activity by Cd at a lower concentration was observed, but as Cd concentration increased, trypsin activity decreased. Maltase activity showed a slight recovery after inhibition by Cd. The activities of SOD and CAT increased initially and decreased subsequently. Cd significantly inhibited the activity of GPx. MDA content increased with increasing concentration of Cd. These results showed that acute Cd exposure led to harmful effects on the alimentary system of crabs, which are likely linked to Cd induced oxidative stress. PMID:23224505

  11. Applications of Electron Linear Induction Accelerators

    NASA Astrophysics Data System (ADS)

    Westenskow*, Glen; Chen, Yu-Jiuan

    Linear Induction Accelerators (LIAs) can readily produce intense electron beams. For example, the ATA accelerator produced a 500 GW beam and the LIU-30 a 4 TW beam (see Chap. 2). Since the induction accelerator concept was proposed in the late 1950s [1, 2], there have been many proposed schemes to convert the beam power to other forms. Categories of applications that have been demonstrated for electron LIAs include:

  12. Enhanced cellulase production by Trichoderma harzianum by cultivation on glycerol followed by induction on cellulosic substrates.

    PubMed

    Delabona, Priscila da Silva; Lima, Deise Juliana; Robl, Diogo; Rabelo, Sarita Cândida; Farinas, Cristiane Sanchez; Pradella, José Geraldo da Cruz

    2016-05-01

    The use of glycerol obtained as an intermediate of the biodiesel manufacturing process as carbon source for microbial growth is a potential alternative strategy for the production of enzymes and other high-value bioproducts. This work evaluates the production of cellulase enzymes using glycerol for high cell density growth of Trichoderma harzianum followed by induction with a cellulosic material. Firstly, the influence of the carbon source used in the pre-culture step was investigated in terms of total protein secretion and fungal morphology. Enzymatic productivity was then determined for cultivation strategies using different types and concentrations of carbon source, as well as different feeding procedures (batch and fed-batch). The best strategy for cellulase production was then further studied on a larger scale using a stirred tank bioreactor. The proposed strategy for cellulase production, using glycerol to achieve high cell density growth followed by induction with pretreated sugarcane bagasse, achieved enzymatic activities up to 2.27 ± 0.37 FPU/mL, 106.40 ± 8.87 IU/mL, and 9.04 ± 0.39 IU/mL of cellulase, xylanase, and β-glucosidase, respectively. These values were 2 times higher when compared to the control experiments using glucose instead of glycerol. This novel strategy proved to be a promising approach for improving cellulolytic enzymes production, and could potentially contribute to adding value to biomass within the biofuels sector. PMID:26883662

  13. Pullulan degrading enzymes of bacterial origin.

    PubMed

    Domań-Pytka, Monika; Bardowski, Jacek

    2004-01-01

    Pullulan degrading enzymes belong to a group of glycosylhydrolases that are widely distributed in nature and are produced by an extremely wide variety of species. Among them the thermophilic and mesophilic bacteria are a rich source of these enzymes. There are many biotechnological applications for these enzymes and a rapidly growing amount of information about their diversity, genetic as well as biochemical and biophysical characteristics. The properties of these enzymes vary and are somewhat linked to the natural environment inhabited by the producing organisms. Genes for these enzymes have been cloned from several strains and their amino acid sequences show highly conserved regions common to the enzymes of the amylase family. Molecular studies have greatly extended our knowledge on pullulan degrading enzymes and their biosynthesis. However, enzyme production levels have usually not been as high as had been assumed possible, and the properties of some enzymes are less than optimal for their industrial applications. Some of these problems can be overcome with the use of good producer organisms, optimized expression/secretion vectors, and site-directed mutagenesis. The molecular biology of pullulan degrading enzymes has been and continues to be a valuable system for studying basic questions of cell biology, such as mechanisms of gene regulation and secretion, and the structure-function relationships of proteins. PMID:15239382

  14. Immobilization of enzymes: a literature survey.

    PubMed

    Brena, Beatriz; González-Pombo, Paula; Batista-Viera, Francisco

    2013-01-01

    The term immobilized enzymes refers to "enzymes physically confined or localized in a certain defined region of space with retention of their catalytic activities, and which can be used repeatedly and continuously." Immobilized enzymes are currently the subject of considerable interest because of their advantages over soluble enzymes. In addition to their use in industrial processes, the immobilization techniques are the basis for making a number of biotechnology products with application in diagnostics, bioaffinity chromatography, and biosensors. At the beginning, only immobilized single enzymes were used, after 1970s more complex systems including two-enzyme reactions with cofactor regeneration and living cells were developed. The enzymes can be attached to the support by interactions ranging from reversible physical adsorption and ionic linkages to stable covalent bonds. Although the choice of the most appropriate immobilization technique depends on the nature of the enzyme and the carrier, in the last years the immobilization technology has increasingly become a matter of rational design. As a consequence of enzyme immobilization, some properties such as catalytic activity or thermal stability become altered. These effects have been demonstrated and exploited. The concept of stabilization has been an important driving force for immobilizing enzymes. Moreover, true stabilization at the molecular level has been demonstrated, e.g., proteins immobilized through multipoint covalent binding. PMID:23934795

  15. Evolving hardware as model of enzyme evolution.

    PubMed

    Lahoz-Beltra, R

    2001-06-01

    Organism growth and survival is based on thousands of enzymes organized in networks. The motivation to understand how a large number of enzymes evolved so fast inside cells may be relevant to explaining the origin and maintenance of life on Earth. This paper presents electronic circuits called 'electronic enzymes' that model the catalytic function performed by biological enzymes. Electronic enzymes are the hardware realization of enzymes defined as molecular automata with a finite number of internal conformational states and a set of Boolean operators modelling the active groups of the active site. One of the main features of electronic enzymes is the possibility of evolution finding the proper active site by means of a genetic algorithm yielding a metabolic ring or k-cycle that bears a resemblance to Krebs (k=7) or Calvin (k=4) cycles present in organisms. The simulations are consistent with those results obtained in vitro evolving enzymes based on polymerase chain reaction (PCR) as well as with the general view that suggests the main role of recombination during enzyme evolution. The proposed methodology shows how molecular automata with evolvable features that model enzymes or other processing molecules provide an experimental framework for simulation of the principles governing metabolic pathways evolution and self-organization. PMID:11448522

  16. High-Throughput Enzyme Kinetics Using Microarrays

    SciTech Connect

    Guoxin Lu; Edward S. Yeung

    2007-11-01

    We report a microanalytical method to study enzyme kinetics. The technique involves immobilizing horseradish peroxidase on a poly-L-lysine (PLL)- coated glass slide in a microarray format, followed by applying substrate solution onto the enzyme microarray. Enzyme molecules are immobilized on the PLL-coated glass slide through electrostatic interactions, and no further modification of the enzyme or glass slide is needed. In situ detection of the products generated on the enzyme spots is made possible by monitoring the light intensity of each spot using a scientific-grade charged-coupled device (CCD). Reactions of substrate solutions of various types and concentrations can be carried out sequentially on one enzyme microarray. To account for the loss of enzyme from washing in between runs, a standard substrate solution is used for calibration. Substantially reduced amounts of substrate solution are consumed for each reaction on each enzyme spot. The Michaelis constant K{sub m} obtained by using this method is comparable to the result for homogeneous solutions. Absorbance detection allows universal monitoring, and no chemical modification of the substrate is needed. High-throughput studies of native enzyme kinetics for multiple enzymes are therefore possible in a simple, rapid, and low-cost manner.

  17. Cellulose degradation by oxidative enzymes.

    PubMed

    Dimarogona, Maria; Topakas, Evangelos; Christakopoulos, Paul

    2012-01-01

    Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs), cellobiose dehydrogenases (CDHs) and members of carbohydrate-binding module family 33 (CBM33). PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future. PMID:24688656

  18. Cellulose degradation by oxidative enzymes

    PubMed Central

    Dimarogona, Maria; Topakas, Evangelos; Christakopoulos, Paul

    2012-01-01

    Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs), cellobiose dehydrogenases (CDHs) and members of carbohydrate-binding module family 33 (CBM33). PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future. PMID:24688656

  19. Ethanologenic Enzymes of Zymomonas mobilis

    SciTech Connect

    Ingram, Lonnie O'Neal

    1999-03-01

    Zymomonas mobilis is a unique microorganism in being both obligately fermentative and utilizing a Entner-Doudoroff pathway for glycolysis. Glycolytic flux in this organism is readily measured as evolved carbon dioxide, ethanol, or glucose consumed and exceeds 1 {micro}mole glucose/min per mg cell protein. To support this rapid glycolysis, approximately 50% of cytoplasmic protein is devoted to the 13 glycolytic and fermentative enzymes which constitute this central catabolic pathway. Only 1 ATP (net) is produced from each glucose metabolized. During the past grant period, we have completed the characterization of 11 of the 13 glycolytic genes from Z. mobilis together with complementary but separate DOE-fimded research by a former post-dot and collaborator, Dr. Tyrrell Conway. Research funded in my lab by DOE, Division of Energy Biosciences can be divided into three sections: A. Fundamental studies; B. Applied studies and utility; and C. Miscellaneous investigations.

  20. INFLUENCE OF CYTOCHROME P-450 MIXED IN FRACTIONS OXIDASE INDUCTION ON THE ACUTE TOXICITY TO RAINBOW TROUT (SALMO GAIRDNERI) OF PRIMARY AROMATIC AMINES

    EPA Science Inventory

    The influence of enzyme induction on acute toxicity of aniline and 4-chloroaniline to rainbow trout (Salmo gairdneri) was investigated. or these two xenobiotics, bioactivation reaction are known to occur in mammals. nduction of cytochrome P450 mixed-function oxidase was obtained ...

  1. Induction of Xylose Reductase and Xylitol Dehydrogenase Activities in Pachysolen tannophilus and Pichia stipitis on Mixed Sugars

    PubMed Central

    Bicho, Paul A.; Runnals, P. Lynn; Cunningham, J. Douglas; Lee, Hung

    1988-01-01

    The induction of xylose reductase and xylitol dehydrogenase activities on mixed sugars was investigated in the yeasts Pachysolen tannophilus and Pichia stipitis. Enzyme activities induced on d-xylose served as the controls. In both yeasts, d-glucose, d-mannose, and 2-deoxyglucose inhibited enzyme induction by d-xylose to various degrees. Cellobiose, l-arabinose, and d-galactose were not inhibitory. In liquid batch culture, P. tannophilus utilized d-glucose and d-mannose rapidly and preferentially over d-xylose, while d-galactose consumption was poor and lagged behind that of the pentose sugar. In P. stipitis, all three hexoses were used preferentially over d-xylose. The results showed that the repressibility of xylose reductase and xylitol dehydrogenase may limit the potential of yeast fermentation of pentose sugars in hydrolysates of lignocellulosic substrates. PMID:16347538

  2. Transporter-Enzyme Interplay: Deconvoluting Effects of Hepatic Transporters and Enzymes on Drug Disposition Using Static and Dynamic Mechanistic Models.

    PubMed

    Varma, Manthena V; El-Kattan, Ayman F

    2016-07-01

    A large body of evidence suggests hepatic uptake transporters, organic anion-transporting polypeptides (OATPs), are of high clinical relevance in determining the pharmacokinetics of substrate drugs, based on which recent regulatory guidances to industry recommend appropriate assessment of investigational drugs for the potential drug interactions. We recently proposed an extended clearance classification system (ECCS) framework in which the systemic clearance of class 1B and 3B drugs is likely determined by hepatic uptake. The ECCS framework therefore predicts the possibility of drug-drug interactions (DDIs) involving OATPs and the effects of genetic variants of SLCO1B1 early in the discovery and facilitates decision making in the candidate selection and progression. Although OATP-mediated uptake is often the rate-determining process in the hepatic clearance of substrate drugs, metabolic and/or biliary components also contribute to the overall hepatic disposition and, more importantly, to liver exposure. Clinical evidence suggests that alteration in biliary efflux transport or metabolic enzymes associated with genetic polymorphism leads to change in the pharmacodynamic response of statins, for which the pharmacological target resides in the liver. Perpetrator drugs may show inhibitory and/or induction effects on transporters and enzymes simultaneously. It is therefore important to adopt models that frame these multiple processes in a mechanistic sense for quantitative DDI predictions and to deconvolute the effects of individual processes on the plasma and hepatic exposure. In vitro data-informed mechanistic static and physiologically based pharmacokinetic models are proven useful in rationalizing and predicting transporter-mediated DDIs and the complex DDIs involving transporter-enzyme interplay. PMID:27385183

  3. Induction of heme oxygenase: A general response to oxidant stress in cultured mammalian cells

    SciTech Connect

    Applegate, L.A.; Luscher, P.; Tyrrell, R.M. )

    1991-02-01

    Accumulation of heme oxygenase mRNA is strongly stimulated by treatment of cultured human skin fibroblasts with ultraviolet radiation, hydrogen peroxide, or the sulfhydryl reagent sodium arsenite. Since this will result in a transient reduction in the prooxidant state of cells, the phenomenon may represent an important inducible antioxidant defense mechanism. To examine the generality of the response, we have measured the accumulation of the specific mRNA in a variety of human and mammalian cell types after inducing treatments. Induction by sodium arsenite is observed in all additional human cell types tested. This includes primary epidermal keratinocytes and lung and colon fibroblasts as well as established cell lines such as HeLa, TK6 lymphoblastoid, and transformed fetal keratinocytes. Strong induction of heme oxygenase mRNA is also observed following sodium arsenite treatment of cell lines of rat, hamster, mouse, monkey, and marsupial origin. The agents which lead to induction in cultured human skin fibroblasts fall into two categories: (a) those which are oxidants or can generate active intermediates (ultraviolet A radiation, hydrogen peroxide, menadione, and the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate); (b) agents which are known to interact with or modify cellular glutathione levels (buthionine sulfoximine, sodium arsenite, iodoacetamide, diamide, and cadmium chloride). These observations strongly support the hypothesis that induction of the enzyme is a general response to oxidant stress in mammalian cells and are consistent with the possibility that the cellular redox state plays a key role.

  4. Autophagy induction causes a synthetic lethal sensitization to ribonucleotide reductase inhibition in breast cancer cells

    PubMed Central

    Chen, Yun-Ru; Tsou, Brittany; Hu, Shuya; Ma, Huimin; Liu, Xiyong; Yen, Yun; Ann, David K.

    2016-01-01

    Macroautophagy can promote cellular survival or death depending on the cellular context and its extent. We hypothesized that autophagy induction would synergize with a therapeutic agent targeting the autophagic cargo. To test this hypothesis, we treated breast cancer MDA-MB-231 cells with tamoxifen (TMX), which induces autophagy through an estrogen receptor-independent pathway. Induction of autophagy reduced cellular levels of RRM2, a subunit of ribonucleotide reductase (RR), the rate limiting enzyme in the production of deoxyribonucleotide triphosphates (dNTPs). This autophagy inducer was combined with COH29, an inhibitor developed in our laboratory that targets RR through a novel mechanism. The combination therapy showed synergistic effects on cytotoxicity in vitro and in an in vivo xenograft model. This cytotoxicity was blocked by knockdown of the autophagy protein ATG5 or addition of chloroquine, an autophagy inhibitor. The combined therapy also induced dNTP depletion and massive genomic instability, leading us to hypothesize that combining autophagy induction with RR inhibition can lead to mitotic catastrophe in rapidly dividing cells. We propose that this TMX + COH29 combined therapy may have clinical benefit. Furthermore, autophagy induction may be a general mechanism for augmenting the effects of chemotherapeutic agents PMID:26675256

  5. Molecular dynamics investigation of the ionic liquid/enzyme interface: application to engineering enzyme surface charge.

    PubMed

    Burney, Patrick R; Nordwald, Erik M; Hickman, Katie; Kaar, Joel L; Pfaendtner, Jim

    2015-04-01

    Molecular simulations of the enzymes Candida rugosa lipase and Bos taurus α-chymotrypsin in aqueous ionic liquids 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium ethyl sulfate were used to study the change in enzyme-solvent interactions induced by modification of the enzyme surface charge. The enzymes were altered by randomly mutating lysine surface residues to glutamate, effectively decreasing the net surface charge by two for each mutation. These mutations resemble succinylation of the enzyme by chemical modification, which has been shown to enhance the stability of both enzymes in ILs. After establishing that the enzymes were stable on the simulated time scales, we focused the analysis on the organization of the ionic liquid substituents about the enzyme surface. Calculated solvent charge densities show that for both enzymes and in both solvents that changing positively charged residues to negative charge does indeed increase the charge density of the solvent near the enzyme surface. The radial distribution of IL constituents with respect to the enzyme reveals decreased interactions with the anion are prevalent in the modified systems when compared to the wild type, which is largely accompanied by an increase in cation contact. Additionally, the radial dependence of the charge density and ion distribution indicates that the effect of altering enzyme charge is confined to short range (≤1 nm) ordering of the IL. Ultimately, these results, which are consistent with that from prior experiments, provide molecular insight into the effect of enzyme surface charge on enzyme stability in ILs. PMID:25641162

  6. Enzymes in Fish and Seafood Processing.

    PubMed

    Fernandes, Pedro

    2016-01-01

    Enzymes have been used for the production and processing of fish and seafood for several centuries in an empirical manner. In recent decades, a growing trend toward a rational and controlled application of enzymes for such goals has emerged. Underlying such pattern are, among others, the increasingly wider array of enzyme activities and enzyme sources, improved enzyme formulations, and enhanced requirements for cost-effective and environmentally friendly processes. The better use of enzyme action in fish- and seafood-related application has had a significant impact on fish-related industry. Thus, new products have surfaced, product quality has improved, more sustainable processes have been developed, and innovative and reliable analytical techniques have been implemented. Recent development in these fields are presented and discussed, and prospective developments are suggested. PMID:27458583

  7. Enzymes in Fish and Seafood Processing

    PubMed Central

    Fernandes, Pedro

    2016-01-01

    Enzymes have been used for the production and processing of fish and seafood for several centuries in an empirical manner. In recent decades, a growing trend toward a rational and controlled application of enzymes for such goals has emerged. Underlying such pattern are, among others, the increasingly wider array of enzyme activities and enzyme sources, improved enzyme formulations, and enhanced requirements for cost-effective and environmentally friendly processes. The better use of enzyme action in fish- and seafood-related application has had a significant impact on fish-related industry. Thus, new products have surfaced, product quality has improved, more sustainable processes have been developed, and innovative and reliable analytical techniques have been implemented. Recent development in these fields are presented and discussed, and prospective developments are suggested. PMID:27458583

  8. Industrial Fungal Enzymes: An Occupational Allergen Perspective

    PubMed Central

    Green, Brett J.; Beezhold, Donald H.

    2011-01-01

    Occupational exposure to high-molecular-weight allergens is a risk factor for the development and pathogenesis of IgE-mediated respiratory disease. In some occupational environments, workers are at an increased risk of exposure to fungal enzymes used in industrial production. Fungal enzymes have been associated with adverse health effects in the work place, in particular in baking occupations. Exposure-response relationships have been demonstrated, and atopic workers directly handling fungal enzymes are at an increased risk for IgE-mediated disease and occupational asthma. The utilization of new and emerging fungal enzymes in industrial production will present new occupational exposures. The production of antibody-based immunoassays is necessary for the assessment of occupational exposure and the development of threshold limit values. Allergen avoidance strategies including personal protective equipment, engineering controls, protein encapsulation, and reduction of airborne enzyme concentrations are required to mitigate occupational exposure to fungal enzymes. PMID:21747869

  9. Induction of Indoleamine 2,3 Dioxygenase-1 by Immunostimulatory-DNA Limits Severity of Experimental Colitis

    PubMed Central

    Ciorba, Matthew A; Bettonville, Ellen E; McDonald, Keely G; Metz, Richard; Prendergast, George C; Newberry, Rodney D; Stenson, William F

    2010-01-01

    The chronic inflammatory bowel diseases are characterized by aberrant innate and adaptive immune responses to commensal luminal bacteria. In both human IBD and in experimental models of colitis there is an increased expression of the enzyme indoleamine 2,3 dioxygenase (IDO). IDO expression has the capacity to exert antimicrobial effects and dampen adaptive immune responses. In the murine TNBS model of colitis, inhibition of this enzyme leads to worsened disease severity suggesting that IDO acts as a natural break in limiting colitis. In this investigation we show that induction of IDO-1 by a TLR-9 agonist, immunostimulatory-DNA (ISS-DNA), critically contributes to its colitis limiting capacities. ISS-DNA induces intestinal expression of IDO-1, but not the recently described paralog enzyme IDO-2. This induction occurred in both epithelial cells and in subsets of CD11c+ and CD11b+ cells of the lamina propria which also increase after ISS-ODN. Signaling required for intestinal IDO-1 induction involves interferon dependent pathways, as IDO-1 was not induced in STAT-1 knockout mice. Using both the TNBS and DSS models of colitis we show the importance of IDO-1s induction in limiting colitis severity. The clinical parameters and histologic correlates of colitis in these models were improved by administration of the TLR-9 agonist; however, when the function of IDO is inhibited, the colitis limiting effects of ISS-ODN were abrogated. These findings support the possibility that targeted induction of IDO-1 is an approach deserving further investigation as a therapeutic strategy for diseases of intestinal inflammation. PMID:20181893

  10. Deficient induction of sulfobromophthalein conjugating activity by phenobarbital in hamster liver.

    PubMed

    Foliot, A; Touchard, D; Myara, A; Trivin, F; Chauffert, M

    1987-08-15

    Administration of phenobarbital, a known inducer of glutathione S-transferase activity in rat liver, failed to stimulate sulfobromophthalein (BSP) conjugation by liver cytosol in hamsters. The latter displayed poor ability to conjugate this substrate, despite very high glutathione-conjugating activity with the broad-spectrum substrate 1-chloro-2,4-dinitrobenzene (CDNB). Of the six substrates tested, in this species, 1,2-epoxy-3-(4-nitrophenoxy)propane (ENPP) was the only one whose conjugation was greatly enhanced by phenobarbital (+172%). Nevertheless, hamsters proved as responsive to phenobarbital induction as rats, since it increased their relative liver weight and microsomal enzyme activity. The deficient induction of liver BSP-conjugating activity observed with phenobarbital is consistent with the finding that it did not affect the hepatic transport of this substrate in hamsters. PMID:3606660

  11. 14 CFR 25.1105 - Induction system screens.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Induction system screens. 25.1105 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1105 Induction system screens. If induction system screens are used— (a) Each screen must be upstream of the carburetor; (b)...

  12. 14 CFR 29.1105 - Induction system screens.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Induction system screens. 29.1105 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Induction System § 29.1105 Induction system screens. If induction system screens are used— (a) Each screen must be upstream of the carburetor; (b)...

  13. 14 CFR 23.1091 - Air induction system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Air induction system. 23.1091 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Induction System § 23.1091 Air induction system. (a) The air induction system for each engine and auxiliary power...

  14. 32 CFR 1624.1 - Random selection procedures for induction.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Random selection procedures for induction. 1624... SYSTEM INDUCTIONS § 1624.1 Random selection procedures for induction. (a) The Director of Selective Service shall from time to time establish a random selection sequence for induction by a drawing to...

  15. 14 CFR 23.1105 - Induction system screens.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Induction system screens. 23.1105 Section... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Induction System § 23.1105 Induction system screens. If induction system screens are used— (a) Each screen must...

  16. 14 CFR 25.1093 - Induction system icing protection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Induction system icing protection. 25.1093... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1093 Induction system icing protection. (a) Reciprocating engines. Each reciprocating engine air induction...

  17. 32 CFR 1624.5 - Order to report for induction.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Order to report for induction. 1624.5 Section... INDUCTIONS § 1624.5 Order to report for induction. (a) Immediately upon determining which persons are to be ordered for induction, the Director of Selective Service shall issue to each person selected an Order...

  18. 32 CFR 1624.2 - Issuance of induction orders.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Issuance of induction orders. 1624.2 Section... INDUCTIONS § 1624.2 Issuance of induction orders. The Director of Selective Service, upon receipt of a call..., shall issue orders to report for induction to registrants whose registration records are in the...

  19. 32 CFR 1624.9 - Induction into the Armed Forces.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Induction into the Armed Forces. 1624.9 Section... INDUCTIONS § 1624.9 Induction into the Armed Forces. Registrants in classes 1-A and 1-A-0, who have been... inducted at the MEPS into the Armed Forces....

  20. 32 CFR 1624.9 - Induction into the Armed Forces.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Induction into the Armed Forces. 1624.9 Section... INDUCTIONS § 1624.9 Induction into the Armed Forces. Registrants in classes 1-A and 1-A-0, who have been... inducted at the MEPS into the Armed Forces....

  1. 32 CFR 1624.9 - Induction into the Armed Forces.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Induction into the Armed Forces. 1624.9 Section... INDUCTIONS § 1624.9 Induction into the Armed Forces. Registrants in classes 1-A and 1-A-0, who have been... inducted at the MEPS into the Armed Forces....

  2. 32 CFR 1624.9 - Induction into the Armed Forces.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Induction into the Armed Forces. 1624.9 Section... INDUCTIONS § 1624.9 Induction into the Armed Forces. Registrants in classes 1-A and 1-A-0, who have been... inducted at the MEPS into the Armed Forces....

  3. 32 CFR 1624.9 - Induction into the Armed Forces.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Induction into the Armed Forces. 1624.9 Section... INDUCTIONS § 1624.9 Induction into the Armed Forces. Registrants in classes 1-A and 1-A-0, who have been... inducted at the MEPS into the Armed Forces....

  4. Interaction of firefly luciferase and silver nanoparticles and its impact on enzyme activity

    NASA Astrophysics Data System (ADS)

    Käkinen, Aleksandr; Ding, Feng; Chen, Pengyu; Mortimer, Monika; Kahru, Anne; Ke, Pu Chun

    2013-08-01

    We report on the dose-dependent inhibition of firefly luciferase activity induced by exposure of the enzyme to 20 nm citrate-coated silver nanoparticles (AgNPs). The inhibition mechanism was examined by characterizing the physicochemical properties and biophysical interactions of the enzyme and the AgNPs. Consistently, binding of the enzyme induced an increase in zeta potential from -22 to 6 mV for the AgNPs, triggered a red-shift of 44 nm in the absorbance peak of the AgNPs, and rendered a ‘protein corona’ of 20 nm in thickness on the nanoparticle surfaces. However, the secondary structures of the enzyme were only marginally affected upon formation of the protein corona, as verified by circular dichroism spectroscopy measurement and multiscale discrete molecular dynamics simulations. Rather, inductively coupled plasma mass spectrometry measurement revealed a significant ion release from the AgNPs. The released silver ions could readily react with the cysteine residues and N-groups of the enzyme to alter the physicochemical environment of their neighboring catalytic site and subsequently impair the enzymatic activity.

  5. A new bifunctional chitosanase enzyme from Streptomyces sp. and its application in production of antioxidant chitooligosaccharides.

    PubMed

    Sinha, Sujata; Tripathi, Pushplata; Chand, Subhash

    2012-07-01

    Chitosanases produced by microbes and plants are getting attention to explore vastly available marine waste. Chitooligosaccharides and glucosamine can be produced using chitosanase enzyme and have applications in food, pharma and other industries. A potential microbial chitosanase source was found after isolation and screening of chitosan degrading microbes from garden soil. An isolate, designated as C6 produced chitosanase enzyme upon induction by chitosan substrates. Production of 6 U/ml of chitosanase enzyme was achieved from this isolate on chitosan minimal salt broth medium at 32 °C after 3 days of growth. The enzyme was able to hydrolyse both chitosan and cellulosic substrates. Enzymatic production of D -glucosamine and chitooligosaccharides were studied with various chitosan substrates using crude enzyme. The yield of glucosamine was found to be 40% after 2 h of reaction at 40 °C, and chitosan oligomers were produced having two to six polymerizations at 60 °C reaction temperature. The hydrolysates showed 50% antioxidant activity as compared to ascorbic acid. PMID:22322828

  6. Isolation of a Microsomal Enzyme System Involved in Glucosinolate Biosynthesis from Seedlings of Tropaeolum majus L.

    PubMed Central

    Du, L.; Halkier, B. A.

    1996-01-01

    An in vitro system that converts phenylalanine to phenylacetaldoxime in the biosynthesis of the glucosinolate glucotropaeolin has been established in seedlings of Tropaeolum majus L. exposed to the combined treatment of jasmonic acid, ethanol, and light. The treatment resulted in a 9-fold induction, compared with untreated, dark-grown seedlings, of de novo biosynthesis measured as incorporation of radioactively labeled phenylalanine into glucotropaeolin. Formation of the inhibitory degradation product benzylisothiocyanate during tissue homogenization was prevented by inactivation of the thioglucosidase myrosinase by addition of 100 mM ascorbic acid to the isolation buffer. This allowed the isolation of a biosynthetically active microsomal preparation from the induced T. majus plant material. The enzyme, which catalyzes the conversion of phenylalanine to the corresponding oxime, was sensitive to cytochrome P450 inhibitors, indicating the involvement of a cytochrome P450 in the biosynthetic pathway. It has previously been shown that the oxime-producing enzyme in the biosynthesis of p-hydroxybenzylglucosinolate in Sinapis alba L. is dependent on cytochrome P450, whereas the oxime-producing enzymes in Brassica species have been suggested to be flavin monooxygenases or peroxidase-type enzymes. The result with T. majus provides additional experimental documentation for a similarity between the enzymes converting amino acids into the corresponding oximes in the biosynthesis of glucosinolates and cyanogenic glucosides. PMID:12226332

  7. Stereochemical course, isotope effects, and enzyme inhibitor studies of glaucine metabolism in fungi

    SciTech Connect

    Kerr, K.M.

    1986-01-01

    The microbial transformation of the aporphine alkaloid glaucine by the fungi Fusarium solani (ATCC 12823) and Aspergillus flavipes (ATCC 1030) proceeds with complete substrate stereoselectivity. The fungus F. solani metabolizes only S-(+)-glaucine (1) to dehydroglaucine (3), and A. flavipes metabolizes only R-(-)-glaucine (2) to dehydroglaucine. This facile microbiological reaction is useful in the destructive resolution of racemic mixtures of glaucine, and may provide a model for producing pure enantiomers (either R or S) of other aporphines from racemic mixtures. In order to extend the reaction to other aporphines and related alkaloids, the overall stereochemical course and enzyme(s) involved in the reaction, and the substrate requirements of the enzyme were investigated. The overall stereochemical course of the transformation was examined using C-7 methyl-blocked analogs of glaucine, cis- and trans-7-methylglaucine, as substrates for the fungi. Isolation and examination of residual substrates from semi-preparative scale incubations by MS, PMR, PMR with a chiral shift reagent, OR and ORD indicated that the transformation was enantioselective in the case of A. flavipes. However, only a 10% enrichment of 6aR,7R-cis-7-methylglaucine was observed in F. solani cultures. The oxidation of glaucine can be envisioned as proceeding through one of several mechanisms, each involving a different enzyme system. Deuterium isotope, induction and enzyme inhibitor experiments helped to distinguish between the three mechanisms.

  8. Extracellular enzymes produced by marine eukaryotes, thraustochytrids.

    PubMed

    Taoka, Yousuke; Nagano, Naoki; Okita, Yuji; Izumida, Hitoshi; Sugimoto, Shinichi; Hayashi, Masahiro

    2009-01-01

    Extracellular enzymes produced by six strains of thraustochytrids, Thraustochytrium, Schizochytrium, and Aurantiochytrium, were investigated. These strains produced 5 to 8 kinds of the extracellular enzymes, depending on the species. Only the genus Thraustochytrium produced amylase. When insoluble cellulose was used as substrate, cellulase was not detected in the six strains of thraustochytrids. This study indicates that marine eukaryotes, thraustochytrids, produced a wide variety of extracellular enzymes. PMID:19129663

  9. Advanced development of immobilized enzyme reactors

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.; Schussel, Leonard J.; Carter, Layne

    1991-01-01

    Fixed-bed reactors have been used at NASA-Marshall to purify wastewater generated by an end-use equipment facility, on the basis of a combination of multifiltration unibeds and enzyme unibeds. The enzyme beds were found to effectively remove such targeted organics as urea, alcohols, and aldehydes, down to levels lying below detection limits. The enzyme beds were also found to remove organic contaminants not specifically targeted.

  10. Inhibiting the Function of an Enzyme

    SciTech Connect

    2015-06-17

    In order to stop bacteria from reproducing and causing a disease like tuberculosis, researchers must first block its enzymes' ability to bind with certain molecules. A research team from Brandeis University worked with the Advanced Protein Characterization Facility at Argonne National Laboratory to define 13 different bacterial structures and uncover the mechanism by which their enzymes form and break bonds with molecules. This animation depicts how an enzyme may be inhibited using this knowledge.

  11. Distinct Roles of Major Peptidoglycan Recycling Enzymes in β-Lactamase Production in Shewanella oneidensis

    PubMed Central

    Yin, Jianhua; Mao, Yinting; Ju, Lili; Jin, Miao; Sun, Yiyang; Jin, Shouguang

    2014-01-01

    β-Lactam antibiotics were the earliest discovered and are the most widely used group of antibiotics that work by inactivating penicillin-binding proteins to inhibit peptidoglycan biosynthesis. As one of the most efficient defense strategies, many bacteria produce β-lactam-degrading enzymes, β-lactamases, whose biochemical functions and regulation have been extensively studied. A signal transduction pathway for β-lactamase induction by β-lactam antibiotics, consisting of the major peptidoglycan recycling enzymes and the LysR-type transcriptional regulator, AmpR, has been recently unveiled in some bacteria. Because inactivation of some of these proteins, especially the permease AmpG and the β-hexosaminidase NagZ, results in substantially elevated susceptibility to the antibiotics, these have been recognized as potential therapeutic targets. Here, we show a contrasting scenario in Shewanella oneidensis, in which the homologue of AmpR is absent. Loss of AmpG or NagZ enhances β-lactam resistance drastically, whereas other identified major peptidoglycan recycling enzymes are dispensable. Moreover, our data indicate that there exists a parallel signal transduction pathway for β-lactamase induction, which is independent of either AmpG or NagZ. PMID:25136029

  12. Isolation of Cytoplasmic Enzymes from Pollen 1

    PubMed Central

    Weeden, Norman F.; Gottlieb, Leslie D.

    1980-01-01

    The cytoplasmic isozyme of many cytoplasmic-organelle isozyme pairs, as well as other cytoplasmic enzymes in plants, can be readily obtained from pollen by soaking it in an appropriate buffer for 4 hours. Enzymes localized in subcellular organelles appear not to be released during the soaking period, although they are released if the pollen is crushed. The technique is a useful initial step in studies of subcellular localization of enzymes or for obtaining small quantities of cytoplasmic enzymes free of organellar contaminants. Images PMID:16661444

  13. Finding Sequences for over 270 Orphan Enzymes

    PubMed Central

    Shearer, Alexander G.; Altman, Tomer; Rhee, Christine D.

    2014-01-01

    Despite advances in sequencing technology, there are still significant numbers of well-characterized enzymatic activities for which there are no known associated sequences. These ‘orphan enzymes’ represent glaring holes in our biological understanding, and it is a top priority to reunite them with their coding sequences. Here we report a methodology for resolving orphan enzymes through a combination of database search and literature review. Using this method we were able to reconnect over 270 orphan enzymes with their corresponding sequence. This success points toward how we can systematically eliminate the remaining orphan enzymes and prevent the introduction of future orphan enzymes. PMID:24826896

  14. Liver enzyme alteration: a guide for clinicians

    PubMed Central

    Giannini, Edoardo G.; Testa, Roberto; Savarino, Vincenzo

    2005-01-01

    ISOLATED ALTERATIONS OF BIOCHEMICAL MARKERS OF LIVER DAMAGE in a seemingly healthy patient can present a challenge for the clinician. In this review we provide a guide to interpreting alterations to liver enzyme levels. The functional anatomy of the liver and pathophysiology of liver enzyme alteration are briefly reviewed. Using a schematic approach that classifies enzyme alterations as predominantly hepatocellular or predominantly cholestatic, we review abnormal enzymatic activity within the 2 subgroups, the most common causes of enzyme alteration and suggested initial investigations. PMID:15684121

  15. Reconstitution of Heme Enzymes with Artificial Metalloporphyrinoids.

    PubMed

    Oohora, K; Hayashi, T

    2016-01-01

    An important strategy used in engineering of hemoproteins to generate artificial enzymes involves replacement of heme with an artificial cofactor after removal of the native heme cofactor under acidic conditions. Replacement of heme in an enzyme with a nonnatural metalloporphyrinoid can significantly alter the reactivity of the enzyme. This chapter describes the design and synthesis of three types of artificial metalloporphyrinoid cofactors consisting of mono-, di-, and tri-anionic ligands (tetradehydrocorrin, porphycene, and corrole, respectively). In addition, practical procedures for the preparation of apo-hemoproteins, incorporation of artificial cofactors, and characterization techniques are presented. Furthermore, the representative catalytic activities of artificial enzymes generated by reconstitution of hemoproteins are summarized. PMID:27586344

  16. Modified kinetics of enzymes interacting with nanoparticles

    NASA Astrophysics Data System (ADS)

    Díaz, Sebastián. A.; Breger, Joyce C.; Malanoski, Anthony; Claussen, Jonathan C.; Walper, Scott A.; Ancona, Mario G.; Brown, Carl W.; Stewart, Michael H.; Oh, Eunkeu; Susumu, Kimihiro; Medintz, Igor L.

    2015-08-01

    Enzymes are important players in multiple applications, be it bioremediation, biosynthesis, or as reporters. The business of catalysis and inhibition of enzymes is a multibillion dollar industry and understanding the kinetics of commercial enzymes can have a large impact on how these systems are optimized. Recent advances in nanotechnology have opened up the field of nanoparticle (NP) and enzyme conjugates and two principal architectures for NP conjugate systems have been developed. In the first example the enzyme is bound to the NP in a persistent manner, here we find that key factors such as directed enzyme conjugation allow for enhanced kinetics. Through controlled comparative experiments we begin to tease out specific mechanisms that may account for the enhancement. The second system is based on dynamic interactions of the enzymes with the NP. The enzyme substrate is bound to the NP and the enzyme is free in solution. Here again we find that there are many variables , such as substrate positioning and NP selection, that modify the kinetics.

  17. Designing Artificial Enzymes by Intuition and Computation

    PubMed Central

    Nanda, Vikas; Koder, Ronald L.

    2012-01-01

    The rational design of artificial enzymes either by applying physio-chemical intuition of protein structure and function or with the aid of computation methods is a promising area of research with the potential to tremendously impact medicine, industrial chemistry and energy production. Designed proteins also provide a powerful platform for dissecting enzyme mechanisms of natural systems. Artificial enzymes have come a long way, from simple α-helical peptide catalysts to proteins that facilitate multi-step chemical reactions designed by state-of-the-art computational methods. Looking forward, we examine strategies employed by natural enzymes which could be used to improve the speed and selectivity of artificial catalysts. PMID:21124375

  18. Androgen-metabolizing enzymes: A structural perspective.

    PubMed

    Manenda, Mahder Seifu; Hamel, Charles Jérémie; Masselot-Joubert, Loreleï; Picard, Marie-Ève; Shi, Rong

    2016-07-01

    Androgen-metabolizing enzymes convert cholesterol, a relatively inert molecule, into some of the most potent chemical messengers in vertebrates. This conversion involves thermodynamically challenging reactions catalyzed by P450 enzymes and redox reactions catalyzed by Aldo-Keto Reductases (AKRs). This review covers the structures of these enzymes with a focus on active site interactions and proposed mechanisms. Due to their role in a number of diseases, particularly in cancer, androgen-metabolizing enzymes have been targets of drug design. Hence we will also highlight how existing knowledge of structure is being used to this end. PMID:26924584

  19. Bicontinuous Nanoporous Frameworks: Caged Longevity for Enzymes.

    PubMed

    Bae, Jae-Sung; Jeon, Eunkyung; Moon, Su-Young; Oh, Wangsuk; Han, Sun-Young; Lee, Jeong Hun; Yang, Sung Yun; Kim, Dong-Myung; Park, Ji-Woong

    2016-09-12

    The preparation of bicontinuous nanoporous covalent frameworks, which are promising for caging active enzymes, is demonstrated. The frameworks have three- dimensionally continuous, hydrophilic pores with widths varying between 5 and 30 nm. Enzymes were infiltrated into the bicontinuous pore by applying a pressured enzyme solution. The new materials and methods allowed the amount of caged proteins to be controlled precisely. The resulting enzyme-loaded framework films could be recycled many times with nearly no loss of catalytic activity. Entropic trapping of proteins by a bicontinuous pore with the right size distribution is an unprecedented strategy toward facile in vitro utilization of biocatalysts. PMID:27513827

  20. Relation between Enzymic Catalysis and Energy Coupling

    NASA Astrophysics Data System (ADS)

    Fry, Mitchell; Blondin, George A.; Green, David E.

    1980-10-01

    The principles that underlie enzyme catalysis also apply to energy coupling processes. A comparison is made between a kinase system that mediates the phosphorylation of glucose by ATP (hexokinase), as the prototype for enzymic catalysis, and the mitochondrial electron-transfer complexes, as the prototypes for energy coupling systems. Induced polarization of chemical bonds and charge separation and elimination are common component events of both enzyme catalysis and energy coupling. Thus, definite limits can be imposed on models of energy coupling; they must comply with the basic principles of enzymic catalysis.