1,721,037 research outputs found
The thymus hypocholesterolemic factor (TphF): a bovine thymic superoxide dismutase active on HMG-CoA reductase
No full text1. This work describes the further biochemical characterization of a new calf thymus protein (TphF) and its primary structure. 2. The amino acid sequences, obtained after sequence analysis of peptides derived from the endoproteinase Lys-C digestion, were subjected to a "Protein Data Bank Search" and were found to be identical with regions of bovine superoxide-dismutase (SOD). 3. These data together with those showing the identical electrophoretic migration of SOD and TphF, their same isoelectric point and their immunoreactivity with anti-SOD antibodies, confirm the similarity of these two proteins
Response of young, aged and osteoarthritic human articular chondrocytes to inflammatory cytokines: molecular and cellular aspects
No full textThe aim of this study was to investigate the metabolic properties of human articular chondrocytes derived from young, aged and osteoarthritic subjects and their genetic adaptation to a catabolic challenge (i.e. the inflammatory cytokines interleukin-1alpha and tumor necrosis factor-alpha), in the absence or presence of diacerein, a drug potentially useful in osteoarthritis. Chondrocytes in primary culture were analyzed for newly secreted proteins, metalloproteinase synthesis and activity, and production of nitric oxide by-products. Results show that chondrocytes from normal but aged subjects present biochemical properties closer to osteoarthritic-derived cartilage than to normal young cartilage, as indicated by cell morphology, cell proliferation rate and pattern of protein secretion (in particular stromelysin-1 and interstitial collagenase). According to patient age and cartilage physiopathology, chondrocytes secrete increasing amounts of a protein identified by micro-sequencing as chitinase-like protein. Upon exposure to the inflammatory cytokines, chondrocytes, regardless the age or the status of the donor, significantly enhance their production of stromelysin-1, interstitial collagenase, interleukin-6 and interleukin-8. By contrast, the chitinase-like protein is not modulated by the cytokines. The pattern of protein secretion and metal loproteinase activity in chondrocytes from aged subjects appeared to be different from that of young patients, but was highly expressed in osteoarthritic chondrocytes. Diacerein, at therapeutically useful concentrations, consistently counteracts the stimulatory effect of cytokines on newly secreted proteins, metal loproteinase activity and nitric oxide production, whereas a selective nitric oxide blocker alone is ineffective. These data demonstrate that a specific gene program is turned on in cytokine-stimulated chondrocytes, which involves production of proteins engaged in remodeling and destruction of cartilage matrix. Part of these mechanisms appears to be operative also in unstimulated aged chondrocytes. Diacerein largely prevents the metabolic alterations caused by cytokine exposure in human chondrocytes, possibly through its ability to block early intracellular mediators after cytokine stimulation, such as oxygen radicals. (C) 2002 Elsevier Science B.V./International Society of Matrix Biology. Published by Elsevier Science B.V. All rights reserved
Indagini sul ruolo della poligalatturonasi nella rizottoniosi del cavolfiore.
No full textNel corso di un censimento delle malattie del cavolfiore in Campania, la Rhizoctonia solani Kuhn è stata isolata con frequenza piuttosto elevata da piante presentanti gravi alterazioni dei tessuti corticali a livello del colletto. La gravità della malattia, riscontrata fra l'altro in tutte le principali pIaghe orticole della regione, ci ha indotti da una parte a studiare la resistenza varietale del cavolfiore alla R. solani e dall'altra a intraprendere una ricerca sull'attività enzimatica del fungo. Già alcuni Autori hanno dedicato la loro attenzione a questo ultimo argomento. Bateman, studiando l'attività cellulosolitica (7) e pectolitica (4) della R. Solani, ha evidenziato sia in vitro che in vivo una poligalatturonasi che ritiene responsabile dell'azione macerante (5). Altri Autori hanno mostrato che la R. solani produce anche poligalatturonico e pectina transcliminasi (3, 22). La capacità della R. solani di sintetizzare poligalatturonasi e cellulasi in coltura è stata messa in relazione con la grandezza dei propaguli del fungo (15); la produzione di questi enzimi inoltre è stata studiata in rapporto allo sviluppo delle lesioni su ipocotili di fagiolo durante i primi stadi della malattia (24). Tuttora però non è stato considerato il ruolo degli enzimi pectolitici e cellulosolitici nella patogenesi della rizottoniosi del cavolfiore, né è stato approfondito lo studio delle proprietà chimico-fisiche di questi enzimi
Tomato pectin methylesterase: modeling, fluorescence, and inhibitor interaction studies-comparison with the bacterial (Erwinia chrysanthemi) enzyme
No full textResponse of young, aged and osteoarthritic human articular chondrocytes to inflammatory cytokines: molecular and cellular aspects
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Trimer carboxyl propeptide of collagen I produced by mature osteoblasts is chemotactic for endothelial cells.
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