Oxygen Uptake of Rainbow Trout Oncorhynchus Mykiss Phagocytes Following Stimulation of the Respiratory Burst

1990 ◽  
Vol 154 (1) ◽  
pp. 339-353
Author(s):  
L. A. J. NAGELKERKE ◽  
M. C. PANNEVIS ◽  
D. F. HOULIHAN ◽  
C. J. SECOMBES
Keyword(s):  
Rainbow Trout ◽  
Oxygen Uptake ◽  
Respiratory Burst ◽  
Biological Significance ◽  
Calcium Ionophore ◽  
Head Kidney ◽  
Oxidase Inhibitor ◽  
Ionophore A23187 ◽  
Stimulation Of

The in vitro oxygen uptake of rainbow trout phagocyte-enriched head kidney leucocyte and head kidney macrophage suspensions was monitored. Stimulation of these cells with zymosan or phorbol myristate acetate induced a two-to 10-fold increase in oxygen uptake, the so-called respiratory burst. This respiratory burst activity was markedly enhanced in the presence of the calcium ionophore A23187 and inhibited in the presence of the NADPH oxidase inhibitor diphenyl iodonium or when glucose was absent from the buffer. The presence of sodium azide also inhibited the response of phagocyte-enriched suspensions by approximately 36 %, but only by 16 % for macrophage suspensions. The possible pathways responsible for the respiratory burst in fish phagocytes and its biological significance are discussed.

Inhibition of Platelet Aggregation by Ethanol in Vitro Shows Specificity for Aggregating Agent Used and Is Influenced by Platelet Lipid Composition

1982 ◽  
Vol 48 (01) ◽  
pp. 049-053 ◽  
Author(s):  
C G Fenn ◽  
J M Littleton
Keyword(s):  
Platelet Aggregation ◽  
Lipid Composition ◽  
Saturated Fatty Acids ◽  
Calcium Ionophore ◽  
Cholesterol Content ◽  
Membrane Lipid ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Increased Sensitivity

SummaryEthanol at physiologically tolerable concentrations inhibited platelet aggregation in vitro in a relatively specific way, which may be influenced by platelet membrane lipid composition. Aggregation to collagen, calcium ionophore A23187 and thrombin (low doses) were often markedly inhibited by ethanol, adrenaline and ADP responses were little affected, and aggregation to exogenous arachidonic acid was actually potentiated by ethanol. Aggregation to collagen, thrombin and A23187 was inhibited more by ethanol in platelets enriched with saturated fatty acids than in those enriched with unsaturated fats. Platelets enriched with cholesterol showed increased sensitivity to ADP, arachidonate and adrenaline but this increase in cholesterol content did not appear to influence the inhibition by ethanol of platelet responses. The results suggest that ethanol may inhibit aggregation by an effect on membrane fluidity and/or calcium mobilization resulting in decreased activity of a membrane-bound phospholipase.

scholarly journals The Role of Chitinase Gene Expression in the Defense of Harvested Banana Against Anthracnose Disease

2009 ◽  
Vol 134 (3) ◽  
pp. 379-386 ◽  
Author(s):  
Bao-Cheng Ma ◽  
Wan-Li Tang ◽  
Li-Yan Ma ◽  
Ling-Ling Li ◽  
Lu-Bin Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Disease Resistance ◽  
Disease Severity ◽  
Pathogenic Fungus ◽  
Calcium Ionophore ◽  
Oxidase Inhibitor ◽  
Chitinase Gene ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Diphenylene Iodonium

The pathogenic fungus Colletotrichum musae infects developing green bananas (Musa spp. AAA group), but remains latent until the fruit ripens. The aim of this research was to determine whether the appearance of disease symptoms is regulated by chitinase gene expression following treatment of fruit with benzothiadiazole (BTH) and methyl jasmonate (MeJA), and with physical (heat) and chemical (H2O2 and Ca2+-related) treatments. In bananas inoculated with C. musae, BTH and MeJA lowered disease severity and stimulated higher gene expression compared with the untreated controls during ripening. However, in naturally infected bananas, BTH and MeJA treatments slightly reduced transcription of the chitinase gene in green bananas, but they prolonged gene expression in ripe bananas and significantly reduced disease severity. The combination of H2O2 and the NADPH oxidase inhibitor, diphenylene iodonium, down-regulated chitinase gene expression and compromised disease resistance compared with H2O2 alone. Heat treatment (HT) or the combination of HT followed by CaCl2 reduced disease, but only the latter significantly upregulated chitinase gene expression. The combination of HT and a calcium ionophore (A23187) resulted in different disease indicies and different levels of gene expression depending upon the order of application: HT followed by A23187 induced higher gene expression and lower disease. The results suggest that disease resistance of green bananas could be related to high and prolonged levels of chitinase gene expression, and chitinase could be involved in harvested banana's anthracnose resistance activated by different defense pathway signals, such as BTH, MeJA, H2O2, and Ca2+.

scholarly journals Inhibition of neutrophil oxidative metabolism by lysosomotropic weak bases

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 334-342 ◽  
Author(s):  
B Styrt ◽  
MS Klempner
Keyword(s):  
Phorbol Myristate Acetate ◽  
Oxidative Metabolism ◽  
Respiratory Burst ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Enzyme Complex ◽  
Myristate Acetate ◽  
Ph Gradients ◽  
Weak Bases

Abstract Maintenance of an acidic intralysosomal compartment may be relevant to multiple aspects of neutrophil function. The effect of lysosomal alkalinization on the neutrophil respiratory burst was studied by measuring cytochrome c reduction in response to soluble stimuli in the presence of lysosomotropic weak bases. The weak bases chloroquine, ammonium chloride, methylamine, and clindamycin all raised the intralysosomal pH and inhibited neutrophil oxidative metabolism at concentrations ranging from 0.1 to 100 mmol/L. Inhibition was dose dependent for each base and correlated significantly with the degree of lysosomal alkalinization. Concentrations that did not alkalinize the lysosome did not inhibit the respiratory burst. Inhibition by weak bases was seen when oxidative metabolism was stimulated by phorbol myristate acetate, calcium ionophore A23187, formyl-methionyl-leucyl- phenylalanine, opsonized zymosan, or sodium fluoride. Increasing the stimulus concentration (from 5 ng/mL to 5 micrograms/mL phorbol myristate acetate and from 0.5 to 1 mumol/L A23187) diminished or abolished inhibition by weak bases. Washing the cells after incubation with bases and before stimulation substantially reversed the inhibition. None of the bases impaired detection of superoxide in a cell-free xanthine-xanthine oxidase assay. Other indexes of oxidative metabolism, including oxygen consumption and hydrogen peroxide release, were also inhibited by weak bases. Analysis of particulate NADPH oxidase activity from neutrophils stimulated in the presence of bases suggested that these cells assemble a subnormal amount of an enzyme complex with normal kinetic characteristics. Lysosomotropic weak bases alkalinized the neutrophil lysosome and produced inhibition of oxidative metabolism that was dose related, was not stimulus specific, and was largely reversed by washing the cells before stimulation. A possible explanation would be altered assembly of the enzyme complex involved in respiratory burst activation as a consequence of impaired granule/plasma membrane fusion in the presence of diminished transmembrane pH gradients.

Na+ dependence of in vitro pancreatic amylase release

1975 ◽  
Vol 229 (4) ◽  
pp. 1023-1026 ◽  
Author(s):  
JA Williams
Keyword(s):  
Pancreatic Enzyme ◽  
In Vitro Release ◽  
Ionophore A23187 ◽  
Enzyme Release ◽  
Pancreatic Amylase ◽  
Amylase Release ◽  
Stimulus Secretion Coupling ◽  
Vitro Release ◽  
Stimulation Of

The effects of Na+ on the in vitro release of amylase from mouse pancreas were studied. Replacement of Na+ in the medium by Tris, choline, or sucrose blocked the stimulation of amylase release by bethanechol and caerulein, whereas replacement by Li+ was without effect. The inhibiton was rapid and reversible, with stimulated amylase release linearly related to the log of the medium Na+ concentration over the range of 20-100 mM Na+. In contrast to the inhibition of amylase release stimulated by physiological secretagogues, enzyme release stimulated by the Ca2+ ionophore A23187 was unaffected by removal of Na+ from the medium. Tissue and intracellular Na+ and K+ contents were unchanged after stimulation of secretion by physiological stimulants. It is concluded that Na+ may be important in the early steps of stimulus-secretion coupling leading to the putative rise in intracellular Ca2+ that triggers pancreatic enzyme release.

P0914NEUTROPHIL EXTRACELLULAR TRAPS FORMATION IN HEMODIALYSIS PATIENTS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Adi Litmanovich ◽  
Khaled Khazim ◽  
Kamal Hassan ◽  
Batya Kristal
Keyword(s):  
Calcium Ionophore ◽  
Morbidity And Mortality ◽  
Human Neutrophils ◽  
Dialysis Session ◽  
Ionophore A23187 ◽  
Arterial Line ◽  
Sod Activity ◽  
Dependent Pathway ◽  
Normal Controls

Abstract Background and Aims Hemodialysis (HD) patients suffer from devastatingly high rates of morbidity and mortality due to infections. Neutrophils isolated from HD patients were shown in the past to exhibit impaired phagocytosis in a mechanism yet to be completely elucidated. In 2004, Brinkmann et al. were the first to describe a new form of cell death which they termed Neutrophil Extracellular Trap Formation, or NETosis, in which neutrophils expulse batches of DNA and proteins in response to bacterial or chemical stimuli in order to trap and remove the stimulus. NETosis is further divided into two pathways, NADPH oxidase (NOX)-dependent and NOX-independent, induced in vitro by phorbol 12-myristate 13-acetate (PMA) and Calcium Ionophore (CI), respectively. In this research, we aim to assess the capacities of HD neutrophils to engage in NETosis, hypothesizing they might be diminished similarly to their phagocytic capacities, and to elucidate the underlying mechanism behind this impairment. Method Neutrophils were isolated from whole venous blood of normal controls and from the arterial line of HD patients before the onset of a dialysis session using EasySepTM direct human neutrophils isolation kit. Then, NETosis was induced with either PMA, Calcium Ionophore A23187 or Phosphate-buffered saline (PBS) as negative control. cfDNA released from the cells was quantified by measuring SYTOXTM-green nucleic acid stain fluorescence levels in the supernatant after stimulation using Elisa plate reader and morphological analysis was done under fluorescence microscope. Reactive oxygen species levels were quantified using flow cytometry and superoxide dismutase (SOD) activity was measured using the SOD Assay Kit (Sigma-Aldrich). Protein arginine deiminase 4 (PAD4) expression was assessed by western blotting. Hydrogen peroxide (H2O2) was added exogenously in order to restore NETosis. Results HD isolated neutrophils exhibit decreased NETosis compared with normal controls in response to both PMA in the NOX-dependent pathway and CI in the NOX-independent pathway, as measured by immunofluorescence and cfDNA quantification. In the NOX-dependent pathway SOD activity was found to be 14% decreased in HD patients, resulting in the accumulation of superoxide radicals and decreased production of H2O2. In the NOX-independent pathway, PAD4 expression was found to be significantly decreased as well. NET formation was restored in vitro in HD neutrophils by the addition of exogenous H2O2. Conclusion To date, impaired NETosis was described only in congenital conditions such as chronic granulomatous disease and myeloperoxidase deficiency. To our knowledge, our research is the first to describe an acquired defect in NETosis in end stage renal disease patients undergoing chronic hemodialysis. An intervention aimed to improve neutrophil function in these patients may reduce the morbidity and mortality due to infection-related disease.

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