Search results for "OXIDASE"
showing 10 items of 927 documents
A simple strategy based on photobiotin irradiation for the photoelectrochemical immobilization of proteins on electrode surfaces
2006
Abstract A photoactivable organic polymer was prepared first by electrogeneration of a conductive biotinylated polypyrrole film in acetonitrile electrolyte. The successive anchoring of avidin and photobiotin led to a multilayer configuration. The latter was illuminated with light (wavelength 370–400 nm) in the presence of proteins adsorbed onto its surface. The irradiation allowed the covalent linking of the proteins to the modified electrode. As a result of the photochemical reaction, a monolayer of enzyme (glucose oxidase, GOX or alkaline phosphatase, AP) was covalently bound to the photobiotin-modified surface with retention of their catalytic activities. The surfacic activities were 34 …
Immunological Activity of Ascidian Hemocytes
2001
In ascidians, various hemocyte types and their differentiation stages may be responsible for several immune functions. A central role in the immune effector mechanisms can be assigned to PO-containing hemocytes and prophenoloxidase system. Morula cell in Styela plicata and univacuolar refringent granulocyte in Ciona intestinalis, a probable intermediate stages in the differentiation pathway of morula cell, may be cytotoxic cells. They are involved in immune reactions of solitary and colonial ascidians. We have shown that they are provided with a PO-linked spontaneous cytotoxic activity and recognize mammalian erythrocytes or tumor cells markers. The toxic molecules can be radical oxygen int…
Descending Connections from the Brainstem to the Spinal Cord in the Electric Fish <i>Eigenmannia</i>
1990
The descending connections from the brainstem to the spinal cord in Eigenmannia sp. were demonstrated using the horseradish peroxidase (HRP) technique. The spinal cord was transecte
DEGRADATIVE ENZYMATIC ACTIVITIES IN FRESH-CUT BLOOD ORANGE SLICES DURING CHILLED STORED
2009
Summary Blood-orange fruits are suitable to fresh-cut fruit production because of their chemical compositions. Nevertheless, the main limitation of using freshly cut oranges is their susceptibility to juiciness loss and ascorbic acid degradation because of enzymatic alterations. The aim of this work is: to identify some of the enzymes causing the qualitative decay in blood-orange slices during 15 days of chilled storage (at 4 ± 0.5 °C and 85% RH); to investigate the susceptibility to the previous alterations of five blood-orange clones (Moro nucellare, Sanguinello nucellare, Tarocco arcimusa, Tarocco gallo and Tarocco meli) to select the most suitable one for fresh-cut production. The enzym…
SALINITY EFFECTS ON ENZYMATIC BROWNING AND ANTIOXIDANT CAPACITY OF FRESH-CUT BABY ROMAINE LETTUCE (LACTUCA SATIVA L. CV. DUENDE)
2010
Abstract Enzymatic browning is a main problem encountered in minimal processing and further storage of leafy vegetables, leading to shorter shelf-life of products. Changes in the two oxidative activities, polyphenol oxidase (PPO) and peroxidase (POD), as well as in total phenolic content, colour parameters and antioxidant capacity (assayed with ORAC method), were monitored during 10 days of storage at 4 °C of minimally processed baby Romaine lettuce ( Lactuca sativa L. cv. Duende) cultivated under three different salinity conditions (2.8, 3.8 and 4.8 dS m −1 ), in order to determine the most suitable condition for further processing. Increasing levels of salinity reduced both oxidases activ…
High-Temperature Short-Time Inactivation of Peroxidase by Direct Heating with a Five-Channel Computer-Controlled Thermoresistometer
1997
The thermal inactivation kinetics of horseradish and asparagus peroxidase in high-temperature short-time conditions was studied by heating in a five-channel computer-controlled thermoresistometer. Horseradish peroxidase was heated between 111.5 and 145°C and the reaction was analyzed assuming that two isoenzymes with EaL = 44.1 and Eas = 22.0 kcal/mol were present. Asparagus peroxidase heated from 110 to l20°C reacted with first-order kinetics, with Ea = 20 kcal/mol. The five-channel computer-controlled thermoresistometer enabled us to study the inactivation kinetics of the more labile fraction of horseradish peroxidase at temperatures above 100°C; this equipment was suitable for studying t…
Cellular and Subcellular Localization of Peroxidase Isoenzymes in Plants and Cell Suspension Cultures from Lupinus polyphyllus
1989
Abstract , leaf protoplasts and cell suspension cultures of Lupinus polyphyllus and isolated vacuoles were studied for cellular and subcellular localization of peroxidase isoenzymes. Isoelectric focusing revealed 16 peroxidase isoenzymes. The basic peroxidase isoenzymes are predominantly localized in the vacuole and, to a minor degree, unbound in the intercellular space. The acidic isoenzymes are cell wall-bound in plants and not detectable in suspension-cultured cells. Large amounts (up to 11.0 U/ml) of a single basic isoenzyme are detectable in the spent medium of cell suspension cultures.
Electrochemical biosensors for glucose based on metal nanoparticles
2013
Abstract Nanotechnology has affected almost all aspects of biomedicine. The integration of nanomaterials has contributed to the selectivity, the versatility, the stability and especially the sensitivity of bioelectronic devices, including biosensors. In this field, nanomaterials have been employed as enzyme immobilizers, enzyme stabilizers, surface modifiers or labeling factors or have provided individualized catalytic effects. Among other sensing platforms, glucose biosensors are of special clinical and industrial significance because of their role in monitoring blood-glucose levels in diabetes mellitus, one of the most prevalent metabolic disorders worldwide. Similar to other sensing plat…
Assessing the use of the mitochondrial cox1 marker for use in DNA barcoding of red algae (Rhodophyta)
2011
The red algae, a remarkably diverse group of organisms, are difficult to identify using morphology alone. Following the proposal to use the mitochondrial cytochrome c oxidase subunit 1 (cox1) for DNA barcoding animals, we assessed the use of this, ne in the identification of red algae using 48 samples plus 31 sequences obtained from GenBank. The data set spanned six gene orders of red algae: the Bangiales, Ceramiales, Corallinales, Gigartinales, Gracilariales and Rhodymeniales. The results indicated that species could be discriminated. Intraspecific variation was between 0 and 4 bp over 539 bp analyzed except in Mastocarpus stellatus (0-14 bp) and Gracilaria gracilis (0-11 bp). Cryptic dive…
The musculature of the electric fish Eigenmannia virescens (South American green knife fish) characterized with cytochrome oxidase staining
1986
Using cytochrome C-oxidase staining, different types of somatic musculature were clearly distinguished in the gymnotoid fish Eigenmannia virescens. Except for a few thin fibres in the region of the horizontal septum, which stained faintly, no others in the trunk muscle stained. Strong staining appeared in the fibres of the anal fin muscles. According to the classification of fish musculature into white, intermediate and red, only the locomotory organ of this fish has red fibres, whereas the trunk muscles are white. The red muscles along the horizontal septum, found in all other fish which have been investigated in this respect, seem to be absent. This is noteworthy since the anal fin alone …