Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.3.1 (NADPH oxidase)
 11,281 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mycoplasmalike organisms (MLOs), purified from aster yellows-infected plants were osmotically lysed, and the membranes were separated from the cytoplasmic fraction through differential centrifugation. Electron microscopic examinations of sections of the purified MLOs and the isolated membranes showed pleomorphic bodies and unit membranous empty vesicles, respectively. Cell fractions were tested for NADH oxidase, NADPH oxidase, ATPase, RNase, DNase, and p-nitrophenyl phosphatase activity. NADH oxidase and ATPase were confined to the membrane fraction and NADPH oxidase to the cytoplasmic fraction of the MLOs. para-Nitrophenyl phosphatase, RNase, and DNase activities were detected in both membrane and cytoplasmic fractions, but p-nitrophenyl phosphatase and RNase appeared to be associated with membranes and DNase with the cytoplasmic fraction. Glucose-6-phosphate dehydrogenase was found in the cytoplasmic fraction of the MLO cells. Our findings on the distribution of enzymes in MLO cells and cell fractions are the first basic documentation on nonhelical, nonculturable microbes parasitic to plants.
 ...
PMID:Enzymatic activities in cell fractions of mycoplasmalike organisms purified from aster yellows-infected plants. 299 32

Coronary microvascular endothelial cells exert (patho)physiological effects on the function of cardiac myocytes, which may be studied experimentally using pure cell populations. As an essential pre-requisite to the investigation of cells from gene-modified mice, we studied the phenotypic properties of coronary microvascular endothelial cells isolated from normal mice, and biochemically characterized the superoxide production by these cells. Microvascular endothelial cells were isolated from devitalized mouse ventricular tissue after sequential digestion with collagenase, trypsin and DNase. Coronary microvascular endothelial cells were separated from cardiac myocytes and other cells by differential centrifugation, plating and culture. Mouse coronary microvascular endothelial cells showed an irregular "cobblestone" morphology at confluence, were >98% positive for CD31 by FACS analysis, and were also positive for VE-cadherin and endothelial-type nitric oxide synthase (eNOS) by confocal microscopy. The cells took up fluorescently labelled, acetylated low-density lipoprotein, but were negative for a alpha -smooth muscle actin, desmin and cytokeratin. Unlike human endothelial cells, mouse coronary microvascular endothelial cells only weakly expressed von Willebrand factor. Immunoblotting showed that the mouse cells expressed components of a phagocyte-type NADPH oxidase. They exhibited NADPH-dependent O(2)(-)-generating activity, which was increased by angiotensin II but completely inhibited by diphenyleneiodonium. Thus, mouse coronary microvascular endothelial cells express both eNOS and NADPH oxidase, interactions between which may play a role in endothelial cell pathophysiology.
 ...
PMID:Phenotypic properties and characteristics of superoxide production by mouse coronary microvascular endothelial cells. 1144 17

Our previous results indicate that during protoplast isolation an oxidative burst occurs [A.K. Papadakis and KA Roubelakis-Angelakis (1999) Plant Physiol 127:197-205] and that suppression of totipotency is correlated with reduced antioxidant activity and low redox state [A.K. Papadakis et al. (2001b) Plant Physiol 126:434-444]. Polyamines are known to affect cell development and to act as antioxidants. Polyamines applied during isolation of tobacco (Nicotiana tabacum L.) protoplasts reduced the accumulation of O2*- but not that of H2O2. This antioxidant effect is probably due to the inhibition of microsomal membrane NADPH oxidase, which occurred in a concentration-dependent manner, with spermine exerting the highest inhibitory effect. However, during protoplast culture, polyamine oxidase activity increased severalfold in spermidine- and spermine-treated protoplasts, concomitant with H2O2 titers. A cell death program was executed in untreated protoplasts, as documented by membrane malfunction, induced DNase activity, DNA fragmentation and a positive TUNEL reaction. Protoplast cell death was prevented in protoplasts treated with putrescine, but not by treatment with spermidine or spermine, which rather had the opposite effect. The data presented suggest that PAs may be implicated in the expression of plant protoplast totipotency.
 ...
PMID:Polyamines inhibit NADPH oxidase-mediated superoxide generation and putrescine prevents programmed cell death induced by polyamine oxidase-generated hydrogen peroxide. 1551 51

Eimeria bovis infections are under immunological control and recent studies have emphasized the role of early PMN-mediated innate immune responses in infected calves. Neutrophil extracellular traps (NETs) have recently been demonstrated to act as a killing mechanism of PMN against several pathogens. In the present study, the interactions of bovine PMN with sporozoites of E. bovis were investigated in this respect in vitro. For demonstration and quantification of NET formation, extracellular DNA was stained by Sytox Orange. Fluorescence images after Sytox Orange staining as well as scanning electron microscopy (SEM) showed NET formation to occur upon contact with E. bovis sporozoites. Exposure of PMN to viable sporozoites induced stronger NET formation than to dead or homogenized parasites. NET formation was abolished by treatment with DNase and could be reduced by diphenylene iodonium, which is described as a potent inhibitor of NADPH oxidase. After sporozoite and PMN co-culture, extracellular fibres were found attached to sporozoites and seemed to trap them, strongly suggesting that NETs immobilize E. bovis sporozoites and thereby prevent them from infecting host cells. Thus, transfer of sporozoites, previously being confronted with PMN, to adequate host cells resulted in clearly reduced infection rates when compared to PMN-free controls. NET formation by PMN may therefore represent an effector mechanism in early innate immune reactions against E. bovis. This is the first report indicating Eimeria-induced NET formation.
 ...
PMID:Neutrophil extracellular trap formation as innate immune reactions against the apicomplexan parasite Eimeria bovis. 1962 90

Neutrophils kill bacteria on extracellular complexes of DNA fibers and bactericidal proteins known as neutrophil extracellular traps (NETs). The NET composition and the bactericidal mechanisms they use are not fully understood. Here, we show that treatment with deoxyribonuclease (DNase I) impairs a late oxidative response elicited by Gram-positive and Gram-negative bacteria and also by phorbol ester. Isoluminol-dependent chemiluminescence elicited by opsonized Listeria monocytogenes-stimulated neutrophils was inhibited by DNase I, and the DNase inhibitory effect was also evident when phagocytosis was blocked, suggesting that DNase inhibits an extracellular mechanism of reactive oxygen species (ROS) generation. The DNase inhibitory effect was independent of actin polymerization. Phagocytosis and cell viability were not impaired by DNase I. Immunofluorescence analysis shows that myeloperoxidase is present on NETs. Furthermore, granular proteins were detected in NETs from Rab27a-deficient neutrophils which have deficient exocytosis, suggesting that exocytosis and granular protein distribution on NETs proceed by independent mechanisms. NADPH oxidase subunits were also detected on NETs, and the detection of extracellular trap-associated NADPH oxidase subunits was abolished by treatment with DNase I and dependent on cell stimulation. In vitro analyses demonstrate that MPO and NADPH oxidase activity are not directly inhibited by DNase I, suggesting that its effect on ROS production depends on NET disassembly. Altogether, our data suggest that inhibition of ROS production by microorganism-derived DNase would contribute to their ability to evade killing.
 ...
PMID:DNase I inhibits a late phase of reactive oxygen species production in neutrophils. 2037 9

Besnoitia besnoiti infection in cattle is an important emerging protozoan disease in Europe causing economic losses and severe clinical signs, such as generalized dermatitis, orchitis, and vulvitis in affected animals. Neutrophil extracellular trap (NET) formation was recently demonstrated as an important effector mechanism of PMN acting against several invading pathogens. In the present study, interactions of bovine PMN with tachyzoites of B. besnoiti were investigated in this respect in vitro. For the demonstration and quantification of NETs, extracellular DNA was stained by Sytox Orange or Pico Green. Fluorescent illustrations as well as scanning electron microscopy analyses (SEM) showed PMN-promoted NET formation rapidly being induced upon contact with B. besnoiti tachyzoites. Co-localization of extracellular DNA with histones, neutrophil elastase (NE) and myeloperoxidase (MPO) in parasite entrapping structures confirmed the classical characteristics of NET. Exposure of PMN to viable, UV attenuated and dead tachyzoites showed a significant induction of NET formation, but even tachyzoite homogenates significantly promoted NETs when compared to negative controls. NETs were abolished by DNase treatment and were reduced after PMN preincubation with NADPH oxidase-, NE- and MPO-inhibitors. Tachyzoite-triggered NET formation led to parasite entrapment as quantitative assays indicated that about one third of tachyzoites were immobilized in NETs. In consequence, tachyzoites were hampered from active invasion of host cells. Thus, transfer of tachyzoites, previously being confronted with PMN, to adequate host cells resulted in significantly reduced infection rates when compared to PMN-free infection controls. To our knowledge, we here report for the first time B. besnoiti-induced NET formation. Our results indicate that PMN-triggered extracellular traps may represent an important effector mechanism of the host early innate immune response against B. besnoiti which may lead to diminishment of initial parasite infection rates during the acute infection phase.
...
PMID:Neutrophil extracellular traps as innate immune reaction against the emerging apicomplexan parasite Besnoitia besnoiti. 2461 49

Neutrophils, the most abundant leukocytes in the human body, are considered to be the first line of defense in the fight against microorganisms. In this fight neutrophils employ weaponry such as reactive oxygen species produced via the NADPH oxidase complex 2 together with the release of intracellular granules containing antimicrobial agents. The discovery that activated neutrophils release decondensed chromatin as DNase-sensitive neutrophil extracellular traps (NETs) lead to a renewed interest in these leukocytes and the function of NETs in vivo. In this review, we will focus on desirable as well as detrimental features of NETs by the example of gout and pancreatitis. In our models we observed that neutrophils drive the initiation of inflammation and are required for the resolution of inflammation.
...
PMID:Neutrophils and neutrophil extracellular traps orchestrate initiation and resolution of inflammation. 2758 95

Neutrophil extracellular traps (NETs) and the cell death associated with it (NETosis) have been implicated in numerous diseases. Mechanistic studies of NETosis have typically relied on nonphysiological stimuli, such as PMA. The human disease of gout is caused by monosodium urate (MSU) crystals. We observed that DNA consistent with NETs is present in fluid from acutely inflamed joints of gout patients. NETs also coat the crystals found in uninflamed tophi of chronic gout patients. We developed a quantitative, live cell imaging assay, which measures the key features of NETosis, namely, cell death and chromatin decondensation. We show that MSU and other physiologically relevant crystals induce NETosis through a molecular pathway that is distinct from PMA and Candida hyphae. Crystals interact with lysosomes to induce NADPH oxidase-independent cell death, with postmortem chromatin decondensation mediated by neutrophil elastase. The resulting MSU-induced NETs are enriched for actin and are resistant to serum and DNase degradation. These findings demonstrate a distinct physiological NETosis pathway in response to MSU crystals, which coats MSU crystals in DNA that persists in tissues as gouty tophi.
 ...
PMID:Monosodium Urate Crystals Generate Nuclease-Resistant Neutrophil Extracellular Traps via a Distinct Molecular Pathway. 2936 11