Consulta: subjectFacets:"Metal ions"
Registros recuperados: 7
Data/hora: 17/06/2024 08:23:59

Influence of metal ions and organic carbons on denitrification activity of the halotolerant bacterium, Paracoccus pantotrophus P16 a strain from shrimp pond
Provedor de dados: 69
Autores: Pintathong,Punyawatt; Richardson,David J; Spiro,Stephen; Choorit,Wanna.
The effect of metal ions, ferric ion (Fe3+) and molybdenum ion (Mo6+) on the denitrification process of Paracoccus pantotrophus P16 grown under saline conditions was investigated. Results revealed that the dosages of added Fe3+ and Mo6+ significantly accelerated nitrate utilization and nitrite accumulation. Enzymatic studies revealed that the membrane-bound nitrate reductase and the periplasmic nitrite reductase had activities of 998 ± 28 and 373 ± 18 nmol (mg protein)-1 min-1, respectively after growing Paracoccus pantotrophus P16 in medium supplemented with 1.5 µM Fe3+. If provided with 1.5 µM Fe3+and 2.4 µM Mo6+, the membrane-bound nitrate reductase activity increased to 6,223 ± 502 nmol (mg protein)-1 min-1 and the periplasmic nitrite reductase was 344...
Tipo: Journal article
Palavras-chave: Metal ions; Nitrate reductase; Nitrite accumulation; Nitrite reductase; Paracoccus pantotrophus.
Ano: 2009
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582009000200004

Influence of NO2 and metal ions on oxidation of aqueous-phase S(IV) in atmospheric concentrations
Provedor de dados: 42
Autores: Martins,Cláudia R.; Alves,Janete J.F.; Carvalho,Wanessa B.D.; Cardoso,Cristiane S.C.; Andrade,Jailson B. de.
An investigation was made of the influence of atmospheric concentrations (15 or 130 ppbv) of NO2 on the aqueous-phase oxidation rate of S(IV) in the presence and absence of Fe(III), Mn(II) and Cr(VI) metal ions under controlled experimental conditions (pH, T, concentration of reactants, etc.). The reaction rate in the presence of the NO2 flow was slower than the reaction rate using only clean air with an initial S(IV) concentration of 10-4 mol/L. NO2 appears to react with S(IV), producing a kind of inhibitor that slows down the reaction. Conversely, tenfold lower concentrations of S(IV) ([S(IV)]º = 10-5 mol/L) caused a faster reaction in the presence of NO2 than the reaction using purified air. Under these conditions, therefore, the equilibrium shifts to...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Aqueous S(IV) oxidation; Metal ions; NO2; Acid rain formation.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652008000200006

The cellular mechanisms of body iron homeostasis
Provedor de dados: 48
Autores: NUÑEZ,MARCO T; GARATE,MARCO A; ARREDONDO,MIGUEL; TAPlA,VICTORIA; MUÑOZ,PATRICIA.
Cells tightly regulate iron levels through the activity of iron regulatory proteins (IRPs) that bind to RNA motifs called iron responsive elements (IREs). When cells become iron-depleted, IRPs bind to IREs present in the mRNAs of ferritin and the transferrin receptor, resulting in diminished translation of the ferritin mRNA and increased translation of the transferrin receptor mRNA. Similarly, body iron homeostasis is maintained through the control of intestinal iron absorption. Intestinal epithelia cells sense body iron through the basolateral endocytosis of plasma transferrin. Transterrin endocytosis results in enterocytes whose iron content will depend on the iron saturation of plasma transferrin. Cell iron levels, in turn, inversely correlate with...
Tipo: Journal article
Palavras-chave: Metal ions; Intestinal absorption; Ferritin; Transferrin; Homeostasis.
Ano: 2000
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200013

Effect of Hydrostatic Pressure on the Fluorescence of Tryptophan in the Presence of Metal Ions Running title: Effect of pressure on the tryptophan
Provedor de dados: 52
Autores: Bao,Chengman; Tang,Xinhui; Ye,Shuming.
ABSTRACT The effect of pressure on the fluorescence of tryptophan in the presence of metal ions was studied by fluorescence spectrometry. It was found that at 60 MPa, the fluorescence intensity of M/Trp mixtures (M represented metal ions) increased compared to that at atmosphere pressure. The relative fluorescence efficiency of M/Trp mixtures increased with pressure. When the M/Trp ratio was above 10:1, the relative fluorescence efficiency in decreasing order was Cu2+/Trp mixtures, Ni2+/Trp mixtures and Mg2+ (K+)/Trp mixtures. When the ratio was below 10:1, the decreasing order was Cu2+/Trp mixtures and Ni2+ (Mg2+, K+)/Trp mixtures. The relative fluorescence efficiency increased with the concentration of Cu2+ and Ni2+. The variation was relate to the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrostatic pressure; Tryptophan; Fluorescence; Metal ions.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132018000100605

Investigation of factors affecting xylanase activity from Trichoderma harzianum 1073 D3
Provedor de dados: 52
Autores: Isil,Seyis; Nilufer,Aksoz.
In this study, some physiological conditions affecting the activity of xylanase enzyme produced from Trichoderma harzianum 1073 D3 were determined. In addition, stabilization of pH and temperature in liquid and semi-solid state cultivation media were investigated. It was concluded that for maximum xylanase activity, incubation at 60°C in an enzyme incubation medium with pH 5 that contained 1 % xylan was appropriate. The stability studies showed that the enzyme was relatively stable in the pH range 3-7 and retained more than 50 % of its original activity after four months.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Trichoderma harzianum; Xylan; Xylanase; Lignocellulosic material; Enzyme stability; Metal ions.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132005000200004

Antimicrobial and toxicological studies of some metal complexes of 4-methylpiperazine-1-carbodithioate and phenanthroline mixed ligands
Provedor de dados: 58
Autores: Kalia,S.B.; Kaushal,G.; Kumar,M.; Cameotra,S.S.; Sharma,A.; Verma,M.L.; Kanwar,S.S.
A few mixed ligand transition metal carbodithioate complexes of the general formula [M(4-MPipzcdt)x(phen)y]Y (M = Mn(II), Co(II), Zn(II); 4-MPipzcdt = 4-methylpiperazine-1-carbodithioate; phen = 1,10-phenanthroline; x = 1 and y = 2 when Y = Cl; x = 2 and y = 1 when Y = nil) were synthesized and screened for their antimicrobial activity against Candida albicans, Escherichia coli, Pseudomonas aeruginosa,Staphylococcus aureus andEnterococcusfaecalis by disk diffusion method. All the complexes exhibited prominent antimicrobial activity against tested pathogenic strains with the MIC values in the range &lt;8-512 μgmL-1. The complexes [Mn(4-MPipzcdt)2(phen)] and [Co(4-MPipzcdt)(phen)2]Cl inhibited the growth of Candida albicans at a concentration as low as 8...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Antimicrobial; Metal ions; 4-methylpiperazine-1-carbodithioate; MIC; Zone of inhibition.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822009000400024

Influence of metal ions on pellet morphology and polygalacturonase synthesis by Aspergillus niger 3T5B8
Provedor de dados: 58
Autores: Couri,Sônia; Pinto,Gustavo Adolfo Saavedra; Senna,Lilian Ferreira de; Martelli,Hebe Labarthe.
The effects of cations addition on pellet morphology and polygalacturonase (PG) synthesis by Aspergillus niger 3T5B8 were studied and compared with a control system. Fe(II), Cu(II), Zn(II) and Mn(II) were added to the fermentation medium separately, and also as combined groups of cations. The addition of Fe2+ and/or Zn2+ ions was significantly positive to the enzyme production. A positive effect in the biomass content, however, was only obtained when the same metal ions were added separately. On the other hand, Cu2+ and Mn2+ ions had almost no effect on these parameters. The morphology of the pellets was studied by image processing techniques. Small pellets with small cores were usually obtained when Fe2+ and Zn2+ ions were individually or collectively...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Metal ions; Polygalacturonase; Pellet morphology.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822003000100005