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Immobilization of glucose oxidase enzyme (GOD) in large pore ordered mesoporous cage-like FDU-1 silica

Silva, Luis Carlos Cides da; INFANTE, C. M. C.; LIMA, A. W. O.; COSENTINO, I. C.; Fantini, Marcia Carvalho de Abreu; ROCHA, F. R. P.; MASINI, J. C.; MATOS, J. R.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
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55.8%
Large pore ordered mesoporous silica FDU-1 with three-dimensional (3D) face-centered cubic, Fm3m arrangement of rnesopores, was synthesized under strong acid media using B-50-6600 poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) triblock copolymer (EO(39)BO(47)EO(39)), tetraethyl orthosilicate (TEOS) and trimethyl-benzene (TMB). Large pore FDU-1 silica was obtained by using the following gel composition 1TEOS:0.00735B50-6600:0.00735TMB:6HCl:155H(2)O. The pristine material exhibited a BET specific surface area of 684 m(2) g(-1), total pore volume of 0.89 cm(3) g(-1), external surface area of 49 m(2) g(-1) and microporous volume of 0.09 cm(3) g(-1). The enzyme activity was determined by the Flow Injection Analysis-Chemiluminescence (FIA-CL) method. For GOD immobilized on the FDU-1 silica, GOD supernatant and GOD solution, the FIA-CL results were 9.0, 18.6 and 34.0 U, respectively. The value obtained for the activity of the GOD solution with FIA-CL method is in agreement with the 35 U, obtained by spectrophotometry. (C) 2011 Elsevier B.V. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); FAPESP[2007/07646-2]; FAPESP[2008/09284-3]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CNPq; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CAPES; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Peroxidase activity as an indicator of water stress in sweet pepper plants

Klar, Antonio Evaldo; Jadoski, Sidnei Osmar; Lima, Giusepina Pace Pereira
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 441-447
Português
Relevância na Pesquisa
55.85%
The purpose of the study was to evaluate the physiological and biochemical behavior of sweet pepper (Capsicum annuum L.) plants under different soil water availability conditions and the efficiency of the peroxidase (EC. 1.11. 1.7) activity as an indicator of water stress in plants. The experiment was carried out at the Faculdade de Ciências Agronômicas UNESP, Botucatu, SP. Sweet pepper plants were grown for 230 days after transplanting of seedlings and arranged in a completely randomized experimental design with 4 treatments, two irrigation managements (50 and 1500 kPa) and two soil surface managements (presence or absence of black polyethylene covering), and six replications. Physiological activities, such as stomatal transpiration and resistance to water vapor diffusion, were evaluated as well as biochemical activities, such as peroxidase activity and total soluble protein in foliar tissues. It was observed that soil water availability may lead to physiological and biochemical alterations in plants. Successive water stress cycles may promote the development of characteristics responsible for improving plant tolerance to periods of low water availability. The peroxidase enzyme activity showed to be an efficient indicator of water stress in sweet pepper plants.

Effect of divalent metal ions on the activity and stability of β-galactosidase isolated from Kluyveromyces lactis

Adalberto, Paulo Roberto; Massabni, Antônio Carlos; Carmona, Eleonora Cano; Goulart, Antônio José; Marques, Daniela Parreira; Monti, Rubens
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Artigo de Revista Científica
Português
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55.94%
In this study, it was demonstrated that β-galactosidase can be deactivated and reactivated with EDTA and divalent metal ions. The enzyme was deactivated after 20 minutes in EDTA solution. Maximal deactivation at the lowest EDTA concentration (10-3 mol.L-1) occurred in the presence of Tris-HCl buffer (pH 7.0). The enzyme recovered 50% of its initial activity after 10 minutes at Mg2+concentrations higher than 0.1 mmol.L-1. Experimental concentrations of 0.1 mmol.L-1 Mn2+ and 1.0 mmol.L-1 Co2+ were sufficient to reactivate the enzyme to around 300% of the control activity for the Mn2+ ion and nearly 100% for the Co2+ ion. The enzyme gradually lost its activity when the Co2+ concentration was 10-2 mol.L-1. Ni2+ and Zn2+ were unable to restore the catalytic activity. Km app and Vmax app were 1.95 ± 0.05 mmol.L-1 and 5.40 ± 0.86x10-2 mmol.min-1.mg-1, with o-NPG as substrate. Optimal temperature and pH were 34oC and 7.5. The half-life (t1/2) at 30°C was 17.5 min for the holoenzyme and 11.0 min for the apoenzyme. With respect to pH variation, the apoenzyme proved to be more sensitive than the holoenzyme. Keywords: β-galactosidase. Divalent metallic ions. Enzyme activity. Stability. RESUMO Efeito de íons metálicos divalentes na atividade e estabilidade da β-galactosidase isolada de Kluyveromyces lactis Este estudo demonstra como a β-galactosidase pode ser desativada e reativada usando EDTA e íons metálicos divalentes. A enzima foi desativada após 20 minutos na presença de EDTA. Desativação máxima para a menor concentração de EDTA (10-3 mol.L-1) ocorreu na presença do tampão Tris-HCl. A enzima recuperou 50% de sua atividade inicial após 10 minutos na presença de Mg2+ em concentrações superiores a 0...

Enzymatic activity of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase produced by Gordonia polyisoprenivorans

Silva,Andréa Scaramal; Camargo,Flávio Anastácio de Oliveira; Andreazza,Robson; Jacques,Rodrigo Josemar Seminoti; Baldoni,Daiana Bortoluzzi; Bento,Fátima M.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
Relevância na Pesquisa
55.92%
This study aimed to evaluate the environmental conditions for enzyme activity of catechol 1,2-dioxygenase (C1,2O) and catechol 2,3-dioxygenase (C2,3O) produced by Gordonia polyisoprenivorans in cell-free and immobilized extracts. The optimum conditions of pH, temperature, time course and effect of ions for enzyme activity were determined. Peak activity of C1,2O occurred at pH 8.0. The isolate exhibited the highest activity of C2,3O at pH 7.0 and 8.0 for the cell-free extract and immobilized extract, respectively. This isolate exhibited important characteristics such as broad range of pH, temperature and time course for enzyme activity.

Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

Oliveira,E.M.; Santos,R.A.S.; Krieger,J.E.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2000 Português
Relevância na Pesquisa
55.91%
The tripeptide Hip-His-Leu was used to standardize a fluorimetric method to measure tissue angiotensin-converting enzyme (ACE) activity in rats. The fluorescence of the o-phthaldialdehyde-His-Leu adduct was compared in the presence and absence of the homogenate (25 µl) to determine whether the homogenate from different tissues interfered with the fluorimetric determination of the His-Leu product. Only homogenates from lung and renal medulla and cortex showed significantly altered fluorescence intensity. To overcome this problem, the homogenate from these tissues were diluted 10 times with assay buffer. The specificity of the assay was demonstrated by the inhibition of ACE activity with 3 µM enalaprilat (MK-422). There was a linear relationship between product formation and incubation time for up to 90 min for homogenates of renal cortex and medulla and liver, for up to 60 min for ventricles and adrenals and for up to 30 min for the aorta, lung and atrium homogenates. In addition, there was a linear relationship between product formation and the amount of protein in the homogenates within the following range: lung, 30-600 µg; renal cortex and medulla, 40-400 µg; atrium and ventricles, 20-200 µg; adrenal, 20-100 µg; aorta, 5-100 µg; liver...

A continuous fluorescent assay for the determination of plasma and tissue angiotensin I-converting enzyme activity

Alves,M.F.; Araujo,M.C.; Juliano,M.A.; Oliveira,E.M.; Krieger,J.E.; Casarini,D.E.; Juliano,L.; Carmona,A.K.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2005 Português
Relevância na Pesquisa
55.9%
A continuous assay using internally quenched fluorescent peptides with the general sequence Abz-peptidyl-(Dnp)P-OH (Abz = ortho-aminobenzoic acid; Dnp = 2,4-dinitrophenyl) was optimized for the measurement of angiotensin I-converting enzyme (ACE) in human plasma and rat tissues. Abz-FRK(Dnp)P-OH, which was cleaved at the Arg-Lys bond by ACE, was used for the enzyme evaluation in human plasma. Enzymatic activity was monitored by continuous recording of the fluorescence (lambdaex = 320 nm and lambdaem = 420 nm) at 37ºC, in 0.1 M Tris-HCl buffer, pH 7.0, with 50 mM NaCl and 10 µM ZnCl2. The assays can be performed directly in the cuvette of the fluorimeter and the hydrolysis followed for 5 to 10 min. ACE measurements in the plasma of 80 healthy patients with Hip-His-Leu and with Abz-FRK(Dnp)P-OH correlated closely (r = 0.90, P < 0.001). The specificity of the assay was demonstrated by the complete inhibition of hydrolysis by 0.5 µM lisinopril or captopril. Abz-FRK(Dnp)P-OH cleavage by ACE was monitored in rat lung, kidney, heart, and liver homogenates in the presence of a cocktail of inhibitors containing trans-epoxy-succinyl-L-leucylamido-(4-guanido)-butene, pepstatin, phenyl-methylsulfonyl fluoride, N-tosyl-L-phenylalanyl-chloromethyl ketone...

The effects of trace elements, cations, and environmental conditions on protocatechuate 3,4-dioxygenase activity

Silva,Andréa Scaramal da; Jacques,Rodrigo Josemar Seminoti; Andreazza,Robson; Bento,Fátima Menezes; Camargo,Flávio Anastácio de Oliveira
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2013 Português
Relevância na Pesquisa
56.01%
Phenanthracene is a highly toxic organic compound capable of contaminating water and soils, and biodegradation is an important tool for remediating polluted environments. This study aimed to evaluate the effects of trace elements, cations, and environmental conditions on the activity of the protocatechol 3,4-dioxygenase (P3,4O) enzyme produced by the isolate Leifsonia sp. in cell-free and immobilized extracts. The isolate was grown in Luria Bertani broth medium (LB) amended with 250 mg L-1 of phenanthrene. Various levels of pH (4.0-9.0), temperature (5-80 °C), time (0-90 min), trace elements (Cu2+, Hg2+ and Fe3+), and cations (Mg2+, Mn2+, K+ and NH4+) were tested to determine which conditions optimized enzyme activity. In general, the immobilized extract exhibited higher enzyme activity than the cell-free extract in the presence of trace elements and cations. Adding iron yielded the highest relative activity for both cell-free and immobilized extracts, with values of 16 and 99 %, respectively. Copper also increased enzyme activity for both cell-free and immobilized extracts, with values of 8 and 44 %, respectively. Enzyme activity in the phosphate buffer was high across a wide range of pH, reaching 80 % in the pH range between 6.5 and 8.0. The optimum temperatures for enzyme activity differed for cell-free and immobilized extracts...

Use of RAPD, enzyme activity staining, and colony size to differentiate phytopathogenic Fuzarium Oxysporum isolates from Iran

Motallebi,Mostafa; Zamani,Mohammad Reza; Jazayeri,Omid; Harighi,Mohammad Javad
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2002 Português
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65.92%
Fusarium oxysporum is a common soilborn plant pathogen with a worldwide distribution. Fusarium yellows disease of chickpea (Cicer arientinum) caused by F.oxysporum is one of the most destructive soilborn disease which is a major production constraint in chickpea-growing regions of Iran. Three laboratory methods "amplification of genomic DNA using random primers, enzyme activity staining, and colony size determination" have been used to discriminate between highly virulent (HV) and weakly virulent (WV) isolates of F. oxysporum. On the basis of colony size (a traditional morphological method) and the ability of isolates to produce pectic enzymes, five HV isolates were differentiated from three WV isolates. The HV isolates formed large colony (ranging from 10.1 to 12.6 mm in diameter) and showed the same enzyme pattern,while the WV isolates produced small colony (ranging from 5.8 to 7.8 mm in diameter) and had not detectable enzyme activity in the stained overlaying gel. Twelve arbitrary 10-mer primers were tested on these 8 isolates of F. oxysporum by Polymerase Chain Reaction (PCR). Cluster analysis of the data from the DNA amplification by Random Amplified Polymorphic DNA (RAPD), differentiated HV from WV isolates. The results obtained from RAPD test confirmed the classification of these eight isolates based on pathogenicity test...

A biodegradation study of forest biomass by Aspergillus niger F7: correlation between enzymatic activity, hydrolytic percentage and biodegradation index

Sharma,Nivedita; Kaushal,Richa; Gupta,Rakesh; Kumar,Sanjeev
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 Português
Relevância na Pesquisa
55.94%
Aspergillus niger F7 isolated from soil was found to be the potent producer of cellulase and xylanase. The residue of forest species Toona ciliata, Celtris australis, Cedrus deodara and Pinus roxburghii was selected as substrate for biodegradation study due to its easy availability and wide use in industry. It was subjected to alkali (sodium hydroxide) treatment for enhancing its degradation. Biodegradation of forest waste by hydrolytic enzymes (cellulase and xylanase) secreted by A. niger under solid state fermentation (SSF) was explored. SSF of pretreated forest biomass was found to be superior over untreated forest biomass. Highest extracellular enzyme activity of 2201±23.91 U/g by A. niger was shown in pretreated C. australis wood resulting in 6.72±0.20 percent hydrolysis and 6.99±0.23 biodegradation index (BI). The lowest BI of 1.40±0.08 was observed in untreated saw dust of C. deodara having the least enzyme activity of 238±1.36 U/g of dry matter. Biodegradation of forest biomass under SSF was increased many folds when moistening agent i.e. tap water had been replaced with modified basal salt media (BSM). In BSM mediated degradation of forest waste with A. niger, extracellular enzyme activity was increased up to 4089±67.11 U/g of dry matter in turn resulting in higher BI of 15.4±0.41 and percent hydrolysis of 19.38±0.81 in pretreated C. australis wood. A. niger exhibited higher enzyme activity on pretreated biomass when moistened with modified BSM in this study. Statistically a positive correlation has been drawn between these three factors i.e. enzyme activity...

Inhibition of angiotensin converting enzyme activity in cultured endothelial cells by hypoxia.

Stalcup, S A; Lipset, J S; Woan, J M; Leuenberger, P; Mellins, R B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1979 Português
Relevância na Pesquisa
46%
Endothelial cells in tissue culture degrade bradykinin and convert angiotensin I to angiotensin II. These are both functions of a single dipeptidyl hydrolase, angiotensin converting enzyme. Monolayer cultures were prepared from human, rabbit, pig, and calf vessels. Angiotensin converting enzyme activity was assessed by adding either bradykinin or angiotensin I to the cells in culture flasks, and measuring residual peptide over time by radioimmunoassay. Peptide degradation was inhibited by the specific converting enzyme inhibitor, SQ 20881. The flasks were equilibrated with varying hypoxic gas mixtures: hypoxia rapidly (less than 2 min) decreased enzyme activity and room air restored it as rapidly. The extent to which activity was reduced was a direct function of PO2 (r = 0.93, P less than 0.001), and there was no enzyme activity below a PO2 of 30 mm Hg. Four preparations were studied with respect to decrease in enzyme activity by hypoxia: (a) intact cells in monolayer, (b) sonicated cells, (c) sonicated cells from which converting enzyme was partially dissolved by a detergent, and (d) purified converting enzyme. Hypoxia had progressively less of an inhibiting effect on the enzyme activity of the preparations as the degree of cell integrity decreased. Hypoxia inhibits angiotensin converting enzyme activity in cultured endothelial cells...

Secretion of an articular cartilage proteoglycan-degrading enzyme activity by murine T lymphocytes in vitro.

Kammer, G M; Sapolsky, A I; Malemud, C J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1985 Português
Relevância na Pesquisa
45.99%
Destruction of articular cartilage is the hallmark of inflammatory arthritides. Enzymes elaborated by mononuclear cells infiltrating the synovium mediate, in part, the degradation of the cartilage extracellular matrix. Since mononuclear cells are the dominant cell type found in chronic inflammatory synovitis, we investigated whether interaction of immune mononuclear cells with antigen initiated the synthesis and secretion of a proteoglycan-degrading enzyme activity. Proteoglycan-degrading enzyme activity was monitored by the capacity of murine spleen cell conditioned medium to release [3H]serine/35SO4 incorporated into rabbit cartilage proteoglycan monomer fraction (A1D1), and by the relative change in specific viscosity of bovine nasal cartilage proteoglycan monomer. The results demonstrated that both virgin and immune mononuclear cells spontaneously generated proteoglycan-degrading enzyme activity and that cellular activation and proliferation induced by the antigen keyhole limpet hemocyanin or the mitogen phytohemagglutinin was not required. Kinetic studies demonstrated stable release of the enzyme activity over 72 h. Cell separation studies showed that T lymphocytes, a thymoma line, and macrophages separately produced proteoglycan-degrading enzyme activity. The enzyme activity has been partially characterized and appears to belong to a class of neutral pH metal-dependent proteinases. These observations...

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

Aoufouchi, S; Shall, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/07/1997 Português
Relevância na Pesquisa
46%
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...

Atividade enzimática durante a germinação de sementes de Melanoxylon brauna schott sob diferentes temperaturas; Enzymatic activity during germination of Melanoxylon brauna schott at different temperatures

Fonte: UFLA - Universidade Federal de Lavras Publicador: UFLA - Universidade Federal de Lavras
Tipo: Artigo de Revista Científica Formato: text/html
Português
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55.78%
The objective of this study was to investigate the effect of temperature on the oxidative metabolism through the activity of the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) in the embryonic axis and micropylar endosperm of Melanoxylon brauna Schott seeds during germination. The seeds were sown in paper rolls germitest moistened with distilled water and subjected to constant temperatures of 15, 25, 30 and 40ºC for 10 days. Measurements of the activities of enzymes SOD, APX and CAT were made in the seeds germinated under the same conditions described above, and every 12 hours until the samples were taken root protrusion of 50% of the seeds or 168 hours for the temperature 15ºC. There were no activities of the enzymes SOD, APX and CAT in the micropylar endosperm at different temperatures. In the embryonic axis, the activities of the enzymes SOD and CAT showed greater changes over the germination of 15ºC and 40ºC, demonstrating that temperature stress causes oxidative damage. The APX enzyme activity in the embryonic axis was not affected by temperature during germination and its activity was extremely low.; Objetivou-se, com este trabalho, investigar o efeito da temperatura sobre o metabolismo oxidativo...

Genfrequenzen und Enzymaktivität der S-Adenosylhomocystein-Hydrolase in einer kroatischen Population; Gene frequencies and enzyme activity of the s-Adenosylhomocystein-hydrolase in a Croatian population

Thomas, Martina Akua Sitsofe
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
Relevância na Pesquisa
65.86%
Der Verlust der SAH-Hydrolase-Aktivität galt bisher als mit dem Leben nicht vereinbar. Baric et al. berichteten 2004 erstmals von einem kroatischen Jungen mit primärem SAH-Hydrolase-Mangel, der von seinen Eltern zwei verschiedene Defektallele geerbt hat. In dieser Arbeit wurde untersucht, ob es in der kroatischen Bevölkerung eine Häufung von Defektallelen der SAH-Hydrolase gibt. Die populationsgenetische Untersuchung einer Stichprobe von 237 unverwandten Kroaten aus Zagreb mittels SGE und anschließender Zymogrammfärbung ergab für die SAH-Hydrolase folgende Genfrequenzen: SAHH*1= 0,941; SAHH*2=0,032 und SAHH*3=0,006. Zusätzlich wurde ein neuer Phänotyp der SAH-Hydrolase, SAHH 4-1, gefunden. Das Allel SAHH*4 tritt mit einer Genfrequenz von 0,015 auf. Im beobachteten Kollektiv befanden sich drei phänotypisch gesunde Träger eines Defektallels, deren SAH-Hydrolase nur 30-40% der Aktivität ihres entsprechenden SAH-Hydrolase-Phänotyps zeigte. Die Frequenz des stummen Allels SAHH*0 in der kroatischen Population beträgt 0,6%. In der densitometrischen Untersuchung der Zymogramme auf Basis des Proteingehalts zeigten sich für die einzelnen Phänotypen keine Unterschiede in der SAH-Hydrolase-Aktivität. Die quantitative Enzymaktivität der SAH-Hydrolase konnte mittels Spektralphotometrie nicht bestimmt werden...

Functional Analysis of Genetic Variation in Catechol-O-Methyltransferase (COMT): Effects on mRNA, Protein, and Enzyme Activity in Postmortem Human Brain

Chen, Jingshan; Lipska, Barbara K.; Halim, Nader; Ma, Quang D.; Matsumoto, Mitsuyuki; Melhem, Samer; Kolachana, Bhaskar S.; Hyde, Thomas M.; Herman, Mary M.; Apud, Jose; Egan, Michael F.; Kleinman, Joel E.; Weinberger, Daniel R.
Fonte: The American Society of Human Genetics Publicador: The American Society of Human Genetics
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
45.99%
Catechol-O-methyltransferase (COMT) is a key enzyme in the elimination of dopamine in the prefrontal cortex of the human brain. Genetic variation in the COMT gene (MIM 116790) has been associated with altered prefrontal cortex function and higher risk for schizophrenia, but the specific alleles and their functional implications have been controversial. We analyzed the effects of several single-nucleotide polymorphisms (SNPs) within COMT on mRNA expression levels (using reverse-transcriptase polymerase chain reaction analysis), protein levels (using Western blot analysis), and enzyme activity (using catechol methylation) in a large sample (n = 108) of postmortem human prefrontal cortex tissue, which predominantly expresses the -membrane-bound isoform. A common coding SNP, Val158Met (rs4680), significantly affected protein abundance and enzyme activity but not mRNA expression levels, suggesting that differences in protein integrity account for the difference in enzyme activity between alleles. A SNP in intron 1 (rs737865) and a SNP in the 3′ flanking region (rs165599)—both of which have been reported to contribute to allelic expression differences and to be associated with schizophrenia as part of a haplotype with Val—had no effect on mRNA expression levels...

Increased aortic NADPH oxidase activity in rats with genetically high angiotensin-converting enzyme levels

Ocaranza, María Paz; Bargetto, Jorge; Pérez, Alfonso; Galaz, Alfonso; Lavandero González, Sergio; Jalil Milad, Jorge
Fonte: LIPPINCOTT WILLIAMS & WILKINS Publicador: LIPPINCOTT WILLIAMS & WILKINS
Tipo: Artículo de revista
Português
Relevância na Pesquisa
45.99%
In humans and rats, angiotensin I-converting enzyme activity is significantly determined by a gene polymorphism. Homozygous Brown Norway rats have higher plasma angiotensin I-converting enzyme activity and circulating angiotensin II (Ang II) levels than Lewis rats. Because Ang II induces NAD(P) H oxidase activation, we hypothesized here that Brown Norway rats have higher vascular NAD(P) H oxidase activity and superoxide anion production than Lewis rats. Homozygous Brown Norway (n = 15) and Lewis (n = 13) male rats were used. Plasma angiotensin I-converting enzyme activity (by fluorimetry), Ang II levels (by high-performance liquid chromatography and radioimmunoassay), and aortic NAD(P) H oxidase activity, as well as superoxide anion production ( by chemiluminescence with lucigenin) were measured. Plasma angiotensin I-converting enzyme activity and Ang II levels were 100% higher in Brown Norway rats than in Lewis rats (P < 0.05). Aortic angiotensin I-converting enzyme, but not Ang II, was elevated (P < 0.05). Aortic superoxide anion production and NAD(P) H oxidase activity were 300% and 260% higher in Brown Norway than in Lewis rats, respectively (P < 0.05), which was not observed in Brown Norway rats treated with candesartan (10 mg/kg per day for 7 days). Endothelial NO synthase activity in the aorta from Brown Norway rats was significantly lower than in Lewis rats. However...

Influence of cadmium on the metabolic quotient, l - : d -glutamic acid respiration ratio and enzyme activity : microbial biomass ratio under laboratory conditions

Landi, L.; Renella, G.; Moreno, J. L.; Falchini, L.; Nannipieri, P.
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 259768 bytes; application/pdf
Português
Relevância na Pesquisa
65.8%
9 pages, 6 tables, 1 figure.; This study was carried out to investigate the effect of very high cadmium concentrations (50 and 500 μg Cd g–1 soil) on some biochemical and microbiological measurements under laboratory conditions involving daily soil samplings. The data for both DTPA- and water-soluble Cd showed two distinctive patterns during soil incubation; from 0 to 4 days, values were about 50–500 and 1–100 μg g–1 dry weight soil, whereas they decreased markedly after 7 days. Both daily respiration and the ATP content but not the microbial biomass C determined by the fumigation–extraction method were lowered by high DTPA- and water-soluble Cd concentrations. Dehydrogenase and phosphatase activities as well as both enzyme activity : microbial biomass ratios were decreased by the high DTPA- and water-soluble Cd concentrations. In the first 2 days of incubation, the metabolic quotient (qCO2) was also decreased by the highest values of available Cd. The early (after 6 h) mineralization of l- but not d-glutamic acid to CO2 was inhibited during the 0–4 day incubation period by the highest Cd concentration. Possibly the l-enantiomer was used by a larger fraction of soil microorganisms than the d-enantiomer or...

Influence of one or two successive annual applications of organic fertilisers on the enzyme activity of a soil under barley cultivation

Marcote, Isidora; Hernández Fernández Muñoz, María Teresa; García Izquierdo, Carlos; Polo, Alfredo
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
Português
Relevância na Pesquisa
55.89%
8 pages, 6 tables.; The effect of cow manure and two rates of addition of municipal solid waste (MSW) compost on the enzymatic activity of a soil supporting barley cultivation was studied and compared with mineral fertilisation (MF). The experiment was carried out in unirrigated land in field conditions for two years. One set of plots was fertilised only once, at the start of the experiment, while another set of plots was fertilised annually (before each sowing). In general, the organic amendments stimulated soil enzyme activity but mineral fertilisation did not. The annual addition of large quantities of MSW compost, in general, led to lower levels of enzyme activity than similar rates of amendment in the plots receiving a single addition, probably because of the toxic effect which the heavy metals incorporated with the MSW compost had on microbial development. In the second year, plot receiving a single application of organic amendment showed higher protease hydrolysing casein, β-glucosidase and dehydrogenase activities than control or soil with mineral fertilisation. This implied that the addition of organic waste, and particularly MSW compost, had a catalysing effect in the soil which lasted for the following years. Barley yields obtained with organic amendments were...

The effects of trace elements, cations, and environmental conditions on protocatechuate 3,4-dioxygenase activity

Silva, Andréa Scaramal da; Jacques, Rodrigo Josemar Seminoti; Andreazza, Robson; Bento, Fátima Menezes; Camargo, Flávio Anastácio de Oliveira
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/2013 Português
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Phenanthracene is a highly toxic organic compound capable of contaminating water and soils, and biodegradation is an important tool for remediating polluted environments. This study aimed to evaluate the effects of trace elements, cations, and environmental conditions on the activity of the protocatechol 3,4-dioxygenase (P3,4O) enzyme produced by the isolate Leifsonia sp. in cell-free and immobilized extracts. The isolate was grown in Luria Bertani broth medium (LB) amended with 250 mg L-1 of phenanthrene. Various levels of pH (4.0-9.0), temperature (5-80 °C), time (0-90 min), trace elements (Cu2+, Hg2+ and Fe3+), and cations (Mg2+, Mn2+, K+ and NH4+) were tested to determine which conditions optimized enzyme activity. In general, the immobilized extract exhibited higher enzyme activity than the cell-free extract in the presence of trace elements and cations. Adding iron yielded the highest relative activity for both cell-free and immobilized extracts, with values of 16 and 99 %, respectively. Copper also increased enzyme activity for both cell-free and immobilized extracts, with values of 8 and 44 %, respectively. Enzyme activity in the phosphate buffer was high across a wide range of pH, reaching 80 % in the pH range between 6.5 and 8.0. The optimum temperatures for enzyme activity differed for cell-free and immobilized extracts...

The effect of tannin with and without polyethylene glycol on in vitro gas production and microbial enzyme activity

Nsahlai,I.V.; Fon,F.N.; Basha,N.A.D.
Fonte: South African Journal of Animal Science Publicador: South African Journal of Animal Science
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 Português
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The aim was to determine the effect of tannin on the nutritive value and microbial enzyme activity in vitro. The leaves and pods of the Acacia sieberiana and Acacia nilotica trees were subjected to chemical analysis and in vitro fermentation with and without polyethylene glycol (PEG; 35 mg/g). Gas production (GP), true degradability (TD) and the proteolytic and fibrolytic enzyme activities in digesta were determined. Data analyses accounted for the effects of feed type, feed fraction, PEG and their interactions. Leaves and pods had similar NDF and ADF contents in A. sieberiana but differed in both attributes in A. nilotica. The leaves had a higher protein, but lower condensed tannin (CT) contents than the pods. A. sieberiana had more CT than A. nilotica, but both had a similar maximum GP. PEG increased the maximum GP, stimulated GP from the soluble fraction and shortened the lag phase. PEG increased the TD for leaves and pods of A. sieberiana, but suppressed TD in fractions of A. nilotica. PEG also increased the activity of protease enzymes, xylanase, endo- and exocellulases, indicating that tannins depress the digestibility of feeds partly by suppressing the activity of these enzymes. Consequently, condensed tannin depressed the digestibility of feed in the rumen by affecting the activity of enzymes involved in carbohydrate and protein breakdown...