Volatilization of Mercury by an Iron Oxidation Enzyme System in a Highly Mercury-resistantAcidithiobacillus ferrooxidansStrain MON-1

2003 ◽  
Vol 67 (7) ◽  
pp. 1537-1544 ◽  
Author(s):  
Tsuyoshi SUGIO ◽  
Mitsuko FUJII ◽  
Fumiaki TAKEUCHI ◽  
Atsunori NEGISHI ◽  
Terunobu MAEDA ◽  
...  
Keyword(s):  
Enzyme System ◽  
Iron Oxidation ◽  
Oxidation Enzyme

Involvement of Iron Oxidation Enzyme System in Sulfur Oxidation of Acidithiobacillus ferrooxidans ATCC 23270

2007 ◽  
Vol 20-21 ◽  
pp. 443-446 ◽  
Author(s):  
Taher M. Taha ◽  
Tadayoshi Kanao ◽  
Fumiaki Takeuchi ◽  
Tsuyoshi Sugio
Keyword(s):  
Oxidase Activity ◽  
Plasma Membranes ◽  
Cultured Cells ◽  
Enzyme System ◽  
Iron Oxidation ◽  
Growth Yield ◽  
Maximum Growth ◽  
Ferric Sulfate ◽  
Lag Phase ◽  
Oxidation Enzyme

Growth of A. ferrooxidans ATCC 23270 cells in sulfur medium with 0.005% ferric sulfate for 3, 4, 5, 6, 7 and 10 days gave the maximum growth yield of 45, 58, 76, 86, 90 and 95 mg protein per liter medium, respectively. Iron oxidase activities of 1-, 2- and 3- day-cultured cells on sulfur with 0.005% ferric sulfate (3.4, 3.5 and 0.8 μmol Fe2+ oxidized/mg protein/min) were approximately 68, 70 and 16% of iron-grown ATCC 23270 cells (5.0 μmol/mg protein/min). In contrast iron oxidase activities of 1-, 2- and 3-day cultured cells on sulfur without iron (4.9, 3.8 and 2.7 μmol Fe2+ oxidized/mg protein/min) were approximately 98, 76 and 54% of the iron oxidase activity observed in iron-grown ATCC 23270 cell. SFORase activities of 3 day-cultured cell on sulfur with and without ferric sulfate (0.62 and 0.31 μmol Fe2+ produced/mg protein/min) were approximately 20 and 10 fold higher than that of iron-grown cell (0.03 μmol Fe2+ produced/mg protein/min). Both iron oxidase and SFORase activities increased at early-log phase and decreased at late-lag phase during growth of the strain on sulfur with or without Fe3+. The plasma membranes which had iron oxidase activity were prepared not only from iron-grown cells but also sulfur-grown cells. Iron oxidase activities of the plasma membranes prepared from sulfur- and iron-grown cells were 3.6 and 4.5 nmol Fe2+ oxidized per mg protein per min. These results suggest that iron oxidation enzyme system has a role in part in the energy generation of this bacterium from sulfur.

Catabolic Functions of Peroxisomes: Modification by Hypoupidemic Drugs

1983 ◽  
Vol 2 (3) ◽  
pp. 101-109 ◽  
Author(s):  
Paul B. Lazarow
Keyword(s):  
Enzyme System ◽  
Female Rats ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferators ◽  
Marine Oils ◽  
Subcellular Organelle ◽  
Carcinogenic Effects ◽  
The Relationship ◽  
Hypolipidemic Drugs ◽  
Oxidation Enzyme

The peroxisome is a subcellular organelle that is widely distributed in nature and which carries out both catabolic and anabolic functions (Ann. NY Acad. Sch 386:1-550, 1982). The catabolic functions include respiration (based on the formation and decomposition of H2O2) and the ß-oxidation of fatty acids. A number of drugs share the attributes of beingi) hypo-lipidemic, (2) inducers of the peroxisomal ß-oxidation enzyme system, (Lazarow, Science 197: 580-581, 1977), 3) peroxisome proliferators, and 4) carcinogens in rodents. Reddy et al. (Nature 283: 397-398, 1980) have hypothesized that peroxisome proliferators as a class may be carcinogenic Data is presented showing that bezafibrate, at a suitable hypolipidemic dose in rats, induces peroxisomal ß-oxidation but does not cause the striking organelle proliferation commonly observed with hypolipidemic drugs. Similar results have been obtained with clofibrate treatment of female rats. Christiansen et al. (Eur.). Cell Biol. 26: 77-20, 7987) have shown that feeding rats a diet rich in partially hydrogenated marine oils produces changes in the peroxisomes similar to those caused by bezafibrate. Aspirin, which is weakly hypolipidemic and a weak peroxisome proliferator, is apparently not carcinogenic in humans. The evidence indicates that the hypolipidemic effects and the peroxisome proliferative effects of these drugs are largely (although incompletely) dissociable. It suggests the need for considerable caution in evaluating the relationship, if any, between hypolipidemic and carcinogenic effects.

Electron Microscopic and Isozyme Study of a Case of Ochronosis

1972 ◽  
Vol 30 ◽  
pp. 88-89
Author(s):  
Jay W. Cha ◽  
Perry J. Melnick
Keyword(s):  
Benzene Ring ◽  
Enzyme System ◽  
Homogentisic Acid ◽  
Degenerative Changes ◽  
Acid Oxidase ◽  
Electron Microscopic ◽  
Tyrosine Metabolism ◽  
Collagenous Tissues

Hereditary ochronosis in very few cases has been examined electron microscopically or histochemically. In this disease homogentisic acid, a normal intermediary of tyrosine metabolism, forms in excessive amounts. This is believed to be due to absence or defective activity of homogentisic acid oxidase, an enzyme system necessary to break the benzene ring and to further break it down to fumaric and acetoacetic acids. Ochronotic pigment, a polymerized form of homogentisic acid, deposits mainly in mesenchymal tissues. There has been a question whether the pigment originates from the collagenous tissues, or deposits passively, where in contrast to melanin it induces degenerative changes.

The Kidney and Fibrinolysis

1970 ◽  
Vol 24 (01/02) ◽  
pp. 026-032 ◽  
Author(s):  
N. A Marsh
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Enzyme System ◽  
Normal Animal ◽  
Fibrinolytic Enzyme ◽  
The Other ◽  
Exclusion Chromatography ◽  
Normal Urine ◽  
Renal Origin ◽  
Molecular Exclusion Chromatography

SummaryMolecular exclusion chromatography was performed on samples of urine from normal and aminonucleoside nephrotic rats. Normal urine contained 2 peaks of urokinase activity, one having a molecular weight of 22,000 and the other around 200,000. Nephrotic urine contained three peaks of activity with MW’s 126,000, 60,000 and 30,000. Plasma activator determined from euglobulin precipitate had a MW. in excess of 200,000. The results indicate that in the normal animal, plasma plasminogen activator does not escape into the urine in substantial quantities but under the conditions of extreme proteinuria there may be some loss through the kidney. The alteration in urokinase output in nephrotic animals indicates a greatly disordered renal fibrinolytic enzyme system.The findings of this study largely support the hypothesis that plasma plasminogen activator of renal origin and urinary plasminogen activator (urokinase) are different molecular species.

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