Search results for "Acellular"
showing 10 items of 1986 documents
The Role of Mitochondrial Reactive Oxygen Species Formation for Age-Induced Vascular Dysfunction
2010
Aging is an important risk factor for the development of cardiovascular diseases, which can be accelerated by atherosclerosis, diabetes, hypercholesterolemia, or obesity. Vascular aging is mainly characterized by endothelial dysfunction, an alteration of endothelium-dependent signaling processes, and vascular remodeling. The underlying mechanisms include increased production of reactive oxygen species (ROS), inactivation of nitric oxide (•NO), and subsequent formation of reactive nitrogen and oxygen species (RNOS). Elevated RNOS may exhibit new messenger functions by posttranslational oxidative modification of intracellular regulatory proteins or lead to irreversible alterations of biologic…
Reactive oxygen species mediate angiotensin II-induced leukocyte-endothelial cell interactions in vivo
2001
Abstract Chronically elevated angiotensin II (Ang-II)-induced hypertension is partly mediated by superoxide production. In this study, we have investigated whether the leukocyte-endothelial cell interactions elicited by Ang-II involve reactive oxygen species (ROS) generation. Intravital microscopy within the rat mesenteric microvessels was used. Superfusion (60 min) with Ang-II (1 nM) induced significant increases in leukocyte rolling flux, adhesion, and emigration, which were inhibited by pretreatment with superoxide dismutase or catalase. Dihydrorhodamine-123 oxidation indicated that ROS are primarily produced by the vessel wall. Administration of dimethylthiourea, desferrioxamine, or N-a…
Electrochemical sensor for evaluating oxidative stress in airway epithelial cells
2021
Cigarette smoke exposure induces oxidative stress within the airways. Increased oxidative burden contributes to the pathogenesis of chronic lung disorders and is associated with aging and chronic inflammation. Airway epithelial cells highly contribute to Reactive Oxygen Species (ROS) generation within injured and inflamed lung tissues. Among ROS, hydrogen peroxide (H2O2) can be monitored in the extracellular space. Herein, we present an amperometric/voltammetric sensor based on gold nanoparticles and graphene oxide able to detect H2O2 with good sensitivity and selectivity. Using this sensor, H2O2 release was measured in conditioned medium from primary bronchial epithelial cells (PBEC), bron…
Plant-growth-regulating phosphono peptides
1990
Phosphono peptides exhibited plant‐growth‐regulating activity when tested on Lepidium sativum and Cucumis sativus. The studies have provided evidence that the mechanism of action of these compounds may involve the uptake of the phosphono peptides into the plant, intracellular hydrolysis of the peptide bond and release of the P‐terminal aminoalkylphosphonic acid. This acid or its metabolite is then probably responsible for the observed physiological effect.
Regulatory activity of polyunsaturated fatty acids in T-cell signaling.
2009
n-3 Polyunsaturated fatty acids (PUFA) are considered to be authentic immunosuppressors and appear to exert beneficial effects with respect to certain immune-mediated diseases. In addition to promoting T-helper 1 (Th1) cell to T-helper 2 (Th2) cell effector T-cell differentiation, n-3 PUFA may also exert anti-inflammatory actions by inducing apoptosis in Th1 cells. With respect to mechanisms of action, effects range from the modulation of membrane receptors to gene transcription via perturbation of a number of second messenger cascades. In this review, the putative targets of anti-inflammatory n-3 PUFA, activated during early and late events of T-cell activation will be discussed. Studies h…
Mannosyl transferases inSaccharomyces cerevisiae: Evidence for the occurrence of ectomannosyltransferase activity
1981
The subcellular distribution of mannosyltransferases inSaccharomyces cerevisiae was studied following the separation of the plasma membrane from other intracellular membranous systems. Most of the activity was linked to internal membranes, and the rest was located at the level of the plasma membrane. Yeast plasma membranes coated on their external face with concanavalin A when incubated with GDP-[U-14C]mannose incorporated 20% less [U-14C]mannose in glycoproteins and 110% more in glycolipids than plasma membranes alone. This suggested that part of the total mannosyltransferase activity of the plasma membrane is located on its outer surface. A significant incorporation of radioactive mannose…
072 Collagen gene expression and tenascin pattern in normal, osteoarthritic, and rheumatoid connective tissues
1992
The extracellular matrix consists of four major components, namely collagens, elastin, proteoglyeans and glycoproteins. Collagens are important members of the ECM, forming a family of at least t 3 different structurally related proteins. Tenascin, synonymous with cytoactin, hexabrachion and J1, is a new member of matrix glycoproteins with a molecular mass of 1200 kD. It exhibits a "hexabrachion" structure with an ellipsoid central globule from which six arms of 75 nm in length diverge in a T-junction arrangement [1]. Rheumatoid arthritis (RA) belongs to the group of connective tissue diseases. In contrast to abundant data about ECM-changes in systemic sclerodermia [2] the matrix alterations…
The comparative behavior of Lactococcus lactis in free and immobilized culture processes
1998
This study presents the changes in the physiological state of Lactococcus lactis in different actively growing systems. The intracellular pH (pHin), NADH/NAD ratio and lactate dehydrogenase (LDH) activity were measured in free cell batch culture with or without external pH (pHout) control, and in continuous free or immobilized cell reactors. In free cell batch culture it has been shown that the pHin is dependent both on pHout and age of the culture, while in free cell continuous culture the pHin and the pHout are close together. The NADH/NAD ratio varied inversely with the growth rate, which was related to the changes in the metabolic activities in lactococci. The specificity of the immobil…
Characterization of a proteinaceous extracellular coat synthesized by the ?slime? variant of Neurospora crassa
1989
Cells of the “slime” strain of Neurospora crassa synthesize a coherent extracellular material which remains attached to the cell surface, but is released into the liquid medium by shaking. The material was purified and studied by different criteria. By electron microscopy it appears as long wavy sheets which strongly bind concanavalin A, but not wheat germ agglutinin, and maintain their integrity in the absence of structural polysaccharides. Analysis of the purified material revealed that it was free of contaminating membranes; it contained more than 70% protein, 1% neutral sugars (glucose, mannose, fucose and galactose), less than 2% lipids and ca. 4% not-characterized hexosaminelike compo…
Locust flight metabolism studied in vivo by 31P NMR spectroscopy
1991
Flight metabolism of locusts has been extensively studied, but biochemical and physiological methods have led to conflicting results. For this reason the non-invasive and non-destructive method of 31P NMR spectroscopy was used to study migratory locusts, Locusta migratoria, at rest and during flight. 1. In the flight muscle of resting locusts the ratio of phosphoarginine to ATP was the same whether determined by NMR (1.76) or biochemically, but the NMR-visible content of inorganic phosphate (Pi) was only 40% of ATP, i.e., much lower than total Pi as determined biochemically. This suggests that most of the Pi in flight muscle is not free, and hence not available as substrate or effector for …