Chemical bromination of phenol red by hydrogen peroxide is possible in the absence of haloperoxidases

Chemosphere ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 1445-1452 ◽  
Author(s):  
María C. Terrón ◽  
Frank J.M. Verhagen ◽  
Maurice C.R. Franssen ◽  
Jim A. Field
Keyword(s):  
1998 ◽  
Vol 64 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Ulises Urzúa ◽  
Philip J. Kersten ◽  
Rafael Vicuña

ABSTRACT The ligninolytic system of the basidiomycete Ceriporiopsis subvermispora is composed of manganese peroxidase (MnP) and laccase. In this work, the source of extracellular hydrogen peroxide required for MnP activity was investigated. Our attention was focused on the possibility that hydrogen peroxide might be generated by MnP itself through the oxidation of organic acids secreted by the fungus. Both oxalate and glyoxylate were found in the extracellular fluid ofC. subvermispora cultures grown in chemically defined media, where MnP is also secreted. The in vivo oxidation of oxalate was measured; 14CO2 evolution was monitored after addition of exogenous [14C]oxalate to cultures at constant specific activity. In standard cultures, evolution of CO2 from oxalate was maximal at day 6, although the MnP titers were highest at day 12, the oxalate concentration was maximal (2.5 mM) at day 10, and the glyoxylate concentration was maximal (0.24 mM) at day 5. However, in cultures containing low nitrogen levels, in which the pH is more stable, a better correlation between MnP titers and mineralization of oxalate was observed. Both MnP activity and oxidation of [14C]oxalate were negligible in cultures lacking Mn(II). In vitro assays confirmed that Mn(II)-dependent oxidation of [14C]oxalate by MnP occurs and that this reaction is stimulated by glyoxylate at the concentrations found in cultures. In addition, both organic acids supported phenol red oxidation by MnP without added hydrogen peroxide, and glyoxylate was more reactive than oxalate in this reaction. Based on these results, a model is proposed for the extracellular production of hydrogen peroxide by C. subvermispora.


1996 ◽  
Vol 59 (11) ◽  
pp. 1233-1241 ◽  
Author(s):  
BENJAMIN J. JUVEN ◽  
MERLE D. PIERSON

Hydrogen peroxide is responsible for certain bactericidal effects observed in biological systems, such as growth inhibition of one bacterial species by another and killing of invading microorganisms by activated phagocytic cells. H2O2 might be generated in bacteriological media by their exposure to light and/or oxygen and become an important mediator of toxic effects. H2O2 cytotoxicity is apparently due to its capacity—generally mediated by transition metal ions—to generate more reactive and cytotoxic oxygen species such as the hydroxyl radical, which is a powerful oxidant, and which can initiate oxidation of biomolecules. The conversion of H2O2 into more cytotoxic compounds may be potentiated by reducing agents and by peroxidases. Cells may protect themselves against H2O2 toxicity either by the action of catalases or, in the case of DNA damage, by repairing the damage after it has taken place. Assays for the detection and quantitation of H2O2 in cell cultures include those based on (i) catalase-dependent oxidation of formate to CO2, (ii) generation of fluorescent products due to a H2O2- mediated oxidative reaction, (iii) the loss of fluorescence upon the oxidation of scopoletin, (iv) change in absorbance upon oxidation of phenol red, or (v) formation of complexes with peroxidases. Some possible antimicrobial uses of H2O2 in the food industry are presented.


2009 ◽  
Vol 64 (9-10) ◽  
pp. 664-672 ◽  
Author(s):  
Iracilda Z. Carlos ◽  
Marcela B. Quilles ◽  
Camila B. A. Carli ◽  
Danielle C. G. Maia ◽  
Fernanda P. Benzatti ◽  
...  

The activities of perlatolic acid (1), atranorin (2), and lecanoric acid (3) and their derivatives, such as orsellinates and β-methyl orsellinates obtained by alcoholysis, were assessed for stimulation of the release of hydrogen peroxide and nitric oxide in cultures of peritoneal macrophage cells from mice. The hydrogen peroxide production was estimated by oxidation of phenol red, while the Griess reagent was used to determine the nitric oxide production. 1 and 4-methoxy-ethyl orsellinate (XVII) were the compounds that induced the greatest release of H2O2, whereas n-pentyl orsellinate (IV), iso-propyl orsellinate (V), sec-butyl orsellinate (VI), and XVII induced a small release of NO. These results indicate that lichen products and their derivatives have potential immune-modulating activities


2008 ◽  
Vol 73 (6) ◽  
pp. 631-639 ◽  
Author(s):  
Savitri Lodha ◽  
Dipti Vaya ◽  
Rakshit Ameta ◽  
Pinki Punjabi

The photocatalytic degradation of Phenol Red was investigated using thiocyanate complexes of iron, copper, cobalt and hydrogen peroxide. The rate of photocatalytic degradation of the dye was followed spectrophotometrically. The effect of the variation of different parameters, such as pH, concentration of the complexes and dye, amount of H2O2 and light intensity on the rate of photocatalytic degradation was also studied. A tentative mechanism for the photocatalytic degradation of Phenol Red is proposed.


Author(s):  
George E. Childs ◽  
Joseph H. Miller

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.


2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.


2010 ◽  
Vol 34 (8) ◽  
pp. S27-S27
Author(s):  
Xueling Dai ◽  
Ping Chang ◽  
Ke Xu ◽  
Changjun Lin ◽  
Hanchang Huang ◽  
...  

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.


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