scholarly journals Manganese Peroxidase-Dependent Oxidation of Glyoxylic and Oxalic Acids Synthesized by Ceriporiopsis subvermispora Produces Extracellular Hydrogen Peroxide

1998 ◽  
Vol 64 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Ulises Urzúa ◽  
Philip J. Kersten ◽  
Rafael Vicuña
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Acids ◽  
Manganese Peroxidase ◽  
Specific Activity ◽  
Extracellular Fluid ◽  
In Vitro Assays ◽  
Phenol Red ◽  
Ceriporiopsis Subvermispora ◽  
Production Of Hydrogen

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.

scholarly journals Investigating Molecular Mechanisms of Immunotoxicity and the Utility of ToxCast for Immunotoxicity Screening of Chemicals Added to Food

2021 ◽  
Vol 18 (7) ◽  
pp. 3332
Author(s):  
Olga V. Naidenko ◽  
David Q. Andrews ◽  
Alexis M. Temkin ◽  
Tasha Stoiber ◽  
Uloma Igara Uche ◽  
...  
Keyword(s):  
Immune System ◽  
High Throughput ◽  
Environmental Protection Agency ◽  
High Throughput Screening ◽  
Molecular Mechanisms ◽  
Specific Activity ◽  
Laboratory Animals ◽  
In Vitro Assays ◽  
Toxicological Studies

The development of high-throughput screening methodologies may decrease the need for laboratory animals for toxicity testing. Here, we investigate the potential of assessing immunotoxicity with high-throughput screening data from the U.S. Environmental Protection Agency ToxCast program. As case studies, we analyzed the most common chemicals added to food as well as per- and polyfluoroalkyl substances (PFAS) shown to migrate to food from packaging materials or processing equipment. The antioxidant preservative tert-butylhydroquinone (TBHQ) showed activity both in ToxCast assays and in classical immunological assays, suggesting that it may affect the immune response in people. From the PFAS group, we identified eight substances that can migrate from food contact materials and have ToxCast data. In epidemiological and toxicological studies, PFAS suppress the immune system and decrease the response to vaccination. However, most PFAS show weak or no activity in immune-related ToxCast assays. This lack of concordance between toxicological and high-throughput data for common PFAS indicates the current limitations of in vitro screening for analyzing immunotoxicity. High-throughput in vitro assays show promise for providing mechanistic data relevant for immune risk assessment. In contrast, the lack of immune-specific activity in the existing high-throughput assays cannot validate the safety of a chemical for the immune system.

scholarly journals [18F]Amylovis as a Potential PET Probe for β-Amyloid Plaque: Synthesis, In Silico, In vitro and In vivo Evaluations

2019 ◽  
Vol 12 (1) ◽  
pp. 58-71 ◽  
Author(s):  
Suchitil Rivera-Marrero ◽  
Laura Fernández-Maza ◽  
Samila León-Chaviano ◽  
Marquiza Sablón-Carrazana ◽  
Alberto Bencomo-Martínez ◽  
...  
Keyword(s):  
In Silico ◽  
Specific Activity ◽  
Senile Plaques ◽  
Coupling Reaction ◽  
In Vitro Assays ◽  
Mice Model ◽  
Wild Mice ◽  
In Silico Studies

Background: Alzheimer’s disease (AD) is the most common form of dementia. Neuroimaging methods have widened the horizons for AD diagnosis and therapy. The goals of this work are the synthesis of 2-(3-fluoropropyl)-6-methoxynaphthalene (5) and its [18F]-radiolabeled counterpart ([18F]Amylovis), the in silico and in vitro comparative evaluations of [18F]Amylovis and [11C]Pittsburg compound B (PIB) and the in vivo preclinical evaluation of [18F]Amylovis in transgenic and wild mice. </p><p> Methods: Iron-catalysis cross coupling reaction, followed by fluorination and radiofluorination steps were carried out to obtain 5 and 18F-Amylovis. Protein/A&#223; plaques binding, biodistribution, PET/CT Imaging and immunohistochemical studies were conducted in healthy/transgenic mice. </p><p> Results: The synthesis of 5 was successful obtained. Comparative in silico studies predicting that 5 should have affinity to the A&#946;-peptide, mainly through &#960;-&#960; interactions. According to a dynamic simulation study the ligand-A&#946; peptide complexes are stable in simulation-time (&#916;G = -5.31 kcal/mol). [18F]Amylovis was obtained with satisfactory yield, high radiochemical purity and specific activity. The [18F]Amylovis log Poct/PBS value suggests its potential ability for crossing the blood brain barrier (BBB). According to in vitro assays, [18F]Amylovis has an adequate stability in time. Higher affinity to A&#946; plaques were found for [18F]Amylovis (Kd 0.16 nmol/L) than PIB (Kd 8.86 nmol/L) in brain serial sections of 3xTg-AD mice. Biodistribution in healthy mice showed that [18F]Amylovis crosses the BBB with rapid uptake (7 %ID/g at 5 min) and good washout (0.11&#177;0.03 %ID/g at 60 min). Comparative PET dynamic studies of [18F]Amylovis in healthy and transgenic APPSwe/PS1dE9 mice, revealed a significant high uptake in the mice model. </p><p> Conclusion: The in silico, in vitro and in vivo results justify that [18F]Amylovis should be studied as a promissory PET imaging agent to detect the presence of A&#946; senile plaques.

scholarly journals In vitro assessment of the probiotic potential of lactobacilli isolated from Minas artisanal cheese produced in the Araxá region, Minas Gerais state, Brazil

2019 ◽  
Vol 71 (2) ◽  
pp. 647-657 ◽  
Author(s):  
J.G. Silva ◽  
R.D. Castro ◽  
F.M. Sant’Anna ◽  
R.M. Barquete ◽  
L.G. Oliveira ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Gastric Juice ◽  
Minas Gerais ◽  
Starter Cultures ◽  
Probiotic Properties ◽  
Probiotic Potential ◽  
Three Samples ◽  
Production Of Hydrogen ◽  
Artificial Gastric Juice

ABSTRACT Minas artisanal cheese is made from endogenous starter cultures, including lactic acid bacteria (LAB). Some LAB may possess probiotic potential. Thus, this study aimed to evaluate the in vitro probiotic properties of lactobacilli isolated from Minas artisanal cheeses produced in Minas Gerais. Ten samples of lactobacilli, formerly isolated from those cheeses, were submitted to the following assays: antimicrobial susceptibility, tolerance to artificial gastric juice and biliary salts, production of hydrogen peroxide and antagonism against pathogenic and non-pathogenic micro-organisms. Only L. plantarum (C0) was sensitive to all tested antimicrobials, while the other LAB samples were resistant to at least one drug. Six samples were tolerant to artificial gastric juice, and L. brevis (A6) even grew in that medium. Three samples were tolerant to biliary salts. Only L. brevis (E35) produced hydrogen peroxide. Difference (P< 0.05) was observed among the means of inhibition haloes of lactobacilli against Enterococcus faecalis ATCC 19433 and Lactobacillus plantarum C24 in spot-on-the-lawn assay. All samples of lactobacilli inhibited Escherichia coli ATCC 25922, Salmonella enterica var. Typhimurium ATCC 14028 in co-culture antagonism test (P< 0.0001). Most lactobacilli samples showed in vitro probiotic potential. From the tested samples, L. brevis (A6) presented the best results considering all in vitro probiotic tests.

scholarly journals Phylloseptin-1 is Leishmanicidal for Amastigotes of Leishmania amazonensis Inside Infected Macrophages

2020 ◽  
Vol 17 (13) ◽  
pp. 4856
Author(s):  
Selma A. S. Kückelhaus ◽  
Daniela Sant’Ana de Aquino ◽  
Tatiana K. Borges ◽  
Daniel C. Moreira ◽  
Luciana de Magalhães Leite ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Leishmania Amazonensis ◽  
In Vivo Studies ◽  
Public Health Issue ◽  
Neglected Diseases ◽  
No Production ◽  
Tnf Α ◽  
Production Of Hydrogen

Leishmania protozoans are the causal agents of neglected diseases that represent an important public health issue worldwide. The growing occurrence of drug-resistant strains of Leishmania and severe side effects of available treatments represent an important challenge for the leishmaniases treatment. We have previously reported the leishmanicidal activity of phylloseptin-1 (PSN-1), a peptide found in the skin secretion of Phyllomedusa azurea (=Pithecopus azureus), against Leishmania amazonensis promastigotes. However, its impact on the amastigote form of L. amazonensis and its impact on infected macrophages are unknown. In this work, we evaluated the effects of PSN-1 on amastigotes of L. amazonensis inside macrophages infected in vitro. We assessed the production of hydrogen peroxide and nitric oxide, as well as the levels of inflammatory and immunomodulatory markers (TGF-β, TNF-α and IL-12), in infected and non-infected macrophages treated with PSN-1. Treatment with PSN-1 decreased the number of infected cells and the number of ingested amastigotes per cell when compared with the untreated cells. At 32 µM (64 µg/mL), PSN-1 reduced hydrogen peroxide levels in both infected and uninfected macrophages, whereas it had little effect on NO production or TGF-β release. The effect of PSN-1 on IL-12 and TNF-α secretion depended on its concentration, but, in general, their levels tended to increase as PSN-1 concentration increased. Further in vitro and in vivo studies are needed to clarify the mechanisms of action of PSN-1 and its interaction with the immune system aiming to develop pharmacological applications.

Analysis of the Buffering Systems in Dental Plaque

1988 ◽  
Vol 67 (2) ◽  
pp. 438-446 ◽  
Author(s):  
R.P. Shellis ◽  
G.H. Dibdin
Keyword(s):  
Organic Acids ◽  
Bacterial Cell ◽  
Dental Plaque ◽  
Cell Walls ◽  
Buffer Capacity ◽  
Extracellular Fluid ◽  
Soluble Proteins ◽  
Live Bacteria

A semi-micro method was used for investigation of the buffering properties of whole plaque, plaque fluid, and washed plaque bacteria. Artifacts associated with titration of samples containing live bacteria were noted and their effects estimated. All three sample types showed minimal buffering in the region of neutrality, with much stronger buffering in the regions pH 4-5.5 and pH 8-9. For the range pH 4-7, almost 90% of the total buffer capacity of plaque appeared to be accounted for by macromolecules of bacterial cell walls and plaque matrix. Extracellular buffers in plaque fluid removable by centrifugation contributed up to 11%. These buffers (probably soluble proteins, peptides, organic acids, and phosphate) are, potentially at least, capable of exchange with saliva. In vitro, bicarbonate (dissolved in the extracellular fluid) contributed only 2-5% of total buffering; there was no evidence of formation of carbamino compounds. However, in vivo, salivary bicarbonate may be important as a continually replenished source of additional buffering.

In vitro production of hydrogen peroxide by human monocytes obtained from jaundice patients

2001 ◽  
Vol 120 (5) ◽  
pp. A472-A472
Author(s):  
M TREGLIADALLAGO ◽  
J JUKEMURA ◽  
M MACHADO ◽  
J BARBUTO
Keyword(s):  
Hydrogen Peroxide ◽  
Human Monocytes ◽  
In Vitro Production ◽  
Production Of Hydrogen ◽  
Vitro Production

scholarly journals The suppression of manganese superoxide dismutase decreased the survival of human glioblastoma multiforme T98G cells

2017 ◽  
Vol 26 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Novi S. Hardiany ◽  
Mohamad Sadikin ◽  
Nurjati Siregar ◽  
Septelia I. Wanandi
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Glioblastoma Multiforme ◽  
Manganese Superoxide Dismutase ◽  
Superoxide Radical ◽  
Specific Activity ◽  
Human Glioblastoma Multiforme ◽  
Manganese Superoxide ◽  
In Vitro Transfection

Background: Glioblastoma multiforme (GBM) is a primary malignant brain tumor which has poor prognosis. High incidence of oxidative stress-based therapy resistance could be related to the high antioxidant status of GBM cells. Our previous study has reported that manganese superoxide dismutase (MnSOD) antioxidant expression was significantly higher in high grade glioma than in low grade. The aim of this study was to analyze the impact of MnSOD suppression toward GBM cell survival.Methods: This study is an experimental study using human glioblastoma multiforme T98G cell line. Suppression of MnSOD expression was performed using in vitro transfection MnSOD-siRNA. The MnSOD expression was analyzed by measuring the mRNA using real time RT-PCR, protein using ELISA technique, and specific activity of enzyme using inhibition of xantine oxidase. Concentration of reactive oxygen species (ROS) intracellular was determined by measuring superoxide radical and hydrogen peroxide. Cell survival was analyzed by measuring viability, proliferation, and cell apoptosis.Results: In vitro transfection of MnSOD-siRNA suppressed the mRNA, protein, and specific activity of MnSOD. This treatment significantly increased the concentration of superoxide radical; however, it did not influence the concentration of hydrogen peroxide. Moreover, viability MnSOD-suppressing cell significantly decreased, accompanied by increase of cell apoptosis without affecting cell proliferation.Conclusion: The suppression of MnSOD expression leads to decrease glioblastoma multiforme cell survival, which was associated to the increase of cell apoptotic.

In vitro production of hydrogen peroxide by human monocytes obtained from jaundice patients

2001 ◽  
Vol 120 (5) ◽  
pp. A472
Author(s):  
Marisa Treglia-Dal-lago ◽  
Jose Jukemura ◽  
Marcel C.C. Machado ◽  
Jose A.M. Barbuto
Keyword(s):  
Hydrogen Peroxide ◽  
Human Monocytes ◽  
In Vitro Production ◽  
Production Of Hydrogen ◽  
Vitro Production
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