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Antiinflammatory Actions of VIP in the Lungs and Airways
Published in Sami I. Said, Proinflammatory and Antiinflammatory Peptides, 2020
The pesticide paraquat (methyl viologen), known to cause tissue injury by oxidant mechanisms, induced acute injury of isolated guinea pig lungs, perfused in situ with Krebs-4% albumin, and ventilated with 95% O2/5% CO2. Upon infusion of paraquat (100 mg/kg) into the PA, airway pressure increased promptly by 230%, PA pressure increased moderately, and W/D and BAL protein, after 1 hr were significantly elevated. Pre- and co-treatment with VIP (3 μg/kgmin) markedly attenuated or totally prevented all evidence of injury (p < .001).
Interaction of Amebas with Cells
Published in Roberto R. Kretschmer, Amebiasis: Infection and Disease by Entamoeba histolytica, 2020
One of the bacterial enzymes from which trophozoites appear to benefit most is catalase. Amebas have been shown to lack catalase45 and axenically grown trophozoites are very sensitive to hydrogen peroxide (>100 μM). Trophozoites that had ingested aerobic bacteria seemed to be protected from its toxic effects and maintained their virulence even at relatively high concentrations of H2O2 (1 mM).34 Catalase deficient bacteria could not confer protection. Ingested bacterial enzymes are apparently also useful in destroying other oxidized molecules such as superoxide ions, which are induced in the presence of methyl viologen (Paraquat).34
Generation of Active-Oxygen Species by Simple Enzymatic Redox Systems
Published in Robert A. Greenwald, CRC Handbook of Methods for Oxygen Radical Research, 2018
Richard J. Youngman, Erich F. Elstner
The method described here is based on a NADPH-dependent diaphorase activity isolated from Euglena gracilis. Enzymes from other sources have also been examined, some of which showed a requirement for NADH instead of NADPH.15 In general, the observed reactions with the various enzymes were similar but they appeared to differ with respect to redox potentials. Thus, certain enzymes were found to be able to reduce the highly electronegative methyl viologen, while others were inactive. The four redox catalysts used here represent a range of redox potentials and thus could be used to make an approximation of the redox potential of an enzyme isolated from a new source.
A new sight for paraquat poisoning from immunology
Published in Immunopharmacology and Immunotoxicology, 2018
Qiang Wu, Qinliang Xu, Xiangdong Jian, Huaxue Wang, Xiandi He, Beijun Gao, Ke Wang, Baotian Kan
Paraquat (methyl viologen, PQ) is an effective and widely used herbicide in agriculture. However, it is highly toxic to humans and animals and there have been numerous fatalities following accidental or deliberate ingestion. The main molecular mechanism of PQ toxicity is based on redox cycling and intracellular oxidative stress generation [1]. A large amount of reactive oxygen species (ROS) induces multiple organ dysfunction, including lung, kidney, heart, and liver injuries. Pulmonary fibrosis is the most common cause of death after PQ poisoning. Therefore, prevention and treatment of pulmonary fibrosis are the current research focus. However, no effective therapy is available. Considerable neutrophil infiltrate in the lungs has been observed during the destructive phase of PQ poisoning [2]. The current treatment dilemma and pathology suggest that we should reconsider how to treat the poisoning using other methods, such as immunization. However, few reports [3, 4] indicate whether innate immunity contributes to the development of PQ poisoning-induced acute lung injury.
Biointerface: a nano-modulated way for biological transportation
Published in Journal of Drug Targeting, 2020
Pravin Shende, Varun S. Wakade
Electrochemistry approach and redox reagents lead to the formation of redox chemistry biointerface because of non-invasive and quantitative redox-stimuli properties. To create novel supramolecular peptide formation, an increase in selectivity of beta-cyclodextrin (β-CD) is necessary for complexation [37]. The study depicts the peptide trapping of azobenzene and cyclodextrin to synthesise the complex and attach to the irregular surface of the nanoparticle-containing tryptophan with a peptide group. The h–g complex on reacting with nanoparticle creates green-coloured fluorescent dots as the peptides are immobilised onto the surface. This approach stimulates the release of tryptophan peptides via electrochemical reduction of viologen [35]. The dynamic nature of the h–g complex separates the small molecules by redox reaction avoiding significant elements. Fluorescent microscope displays green dots indicating immobilisation of N-tryptophan-containing peptides on the surfaces as uniform peptide arrays [9]. Cell surface contains N-tryptophan for the reduction of viologens (toxic metabolites) by releasing the peptides [48]. Various processes like solid-phase peptide synthesis, thioalkylation and ligation strategies lead to immobilisation and peptide release for separation of the specific peptide from the mixture of peptides [49]. For example, immobilisation of tripeptide arginine–glycine–aspartic acid (RGD) ligands on the gold substrate produces an electrochemical cell adhesive control at biosurface of cell-membrane. Electrochemical activation causes the dissociation of the h–g complex and releases RGD ligands from the surface of the cell for controlling cell adhesion.
Antimicrobial peptide GH12 suppresses cariogenic virulence factors of Streptococcus mutans
Published in Journal of Oral Microbiology, 2018
Yufei Wang, Xiuqing Wang, Wentao Jiang, Kun Wang, Junyuan Luo, Wei Li, Xuedong Zhou, Linglin Zhang
However, beyond the threshold of 1/2 MIC (4 mg/L), all virulence factors of S. mutans were inhibited by GH12. This saltatorial pattern has also been observed when S. mutans was treated by hydrogen peroxide, methyl viologen and chlorhexidine in studies of Bitoun et al. [59]. Thus, for efficiently inhibiting cariogenic virulence of S. mutans, concentration of GH12 should be maintained not lower than 1/2 MIC.