排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
Jelena Djokic Christine Fagotto-Kaufmann Rainer Bartels Valentin Nelea Dieter P. Reinhardt 《The Journal of biological chemistry》2013,288(31):22821-22835
Extracellular short fibulins, fibulin-3, -4, and -5, are components of the elastic fiber/microfibril system and are implicated in the formation and homeostasis of elastic tissues. In this study, we report new structural and functional properties of the short fibulins. Full-length human short fibulins were recombinantly expressed in human embryonic kidney cells and purified by immobilized metal ion affinity chromatography. All three fibulins showed various levels of degradation after the purification procedure. N-terminal sequencing revealed that all three fibulins are highly susceptible to proteolysis within the N-terminal linker region of the first calcium-binding epidermal growth factor domain. Proteolytic susceptibility of the linker correlated with its length. Exposure of these fibulins to matrix metalloproteinase (MMP)-1, -2, -3, -7, -9, and -12 resulted in similar proteolytic fragments with MMP-7 and -12 being the most potent proteases. Fibulin-3 proteolysis was almost completely inhibited in cell culture by the addition of 25 μm doxycycline (a broad spectrum MMP inhibitor). Reducible fibulin-4 dimerization and multimerization were consistently observed by SDS-PAGE, Western blotting, and mass spectrometry. Atomic force microscopy identified monomers, dimers, and multimers in purified fibulin-4 preparations with sizes of ∼10–15, ∼20–25, and ∼30–50 nm, respectively. All short fibulins strongly adhered to human fibroblasts and smooth muscle cells. Although only fibulin-5 has an RGD integrin binding site, all short fibulins adhere at a similar level to the respective cells. Solid phase binding assays detected strong calcium-dependent binding of the short fibulins to immobilized heparin, suggesting that these fibulins may bind cell surface-located heparan sulfate. 相似文献
2.
An in vivo chemotaxis assay in the dog trachea: evidence for chemotactic activity of 8,15-diHETE 总被引:2,自引:0,他引:2
Kirsch C. M.; Sigal E.; Djokic T. D.; Graf P. D.; Nadel J. A. 《Journal of applied physiology》1988,64(5):1792-1795
We describe a new in vivo chemotaxis assay in the dog trachea using a double-balloon endotracheal catheter. When inflated, the two balloons isolate a segment of trachea, which is perfused through Silastic tubes using a peristaltic pump. After instilling a chemotactic agent, the perfusate is sampled periodically to permit characterization of the chemotactic response. We anesthetized four mongrel dogs and ventilated them mechanically through the double-balloon catheter. Two mediators, leukotriene B4 (LTB4) and 8S,15S-dihydroxyeicosatetraenoic acid (8,15-diHETE) were tested in each dog by perfusing the trachea with each mediator in Hanks' balanced salt solution (HBSS) containing ethanol and antibiotics. Aliquots were removed for differential cell counts at fixed time intervals over a 4-h period. Control experiments performed in each dog with the identical concentrations of ethanol and antibiotics in HBSS showed no cellular response before 180 min. At 240 min, the cell counts were 86 +/- 28 (SE) granulocytes/microliter (n = 4). In contrast, both LTB4 and 8,15-diHETE gave a significant cellular response at 120 min (309 +/- 125 and 141 +/- 41 granulocytes/microliter, respectively; P less than 0.05) but did not differ significantly from each other. These results suggest that both LTB4 and 8,15-diHETE can incite inflammatory responses in the dog trachea in vivo. Furthermore, the double-balloon catheter technique promises to be a useful in vivo chemotaxis assay. 相似文献
3.
Airway neutral endopeptidase-like enzyme modulates tachykinin-induced bronchoconstriction in vivo 总被引:10,自引:0,他引:10
D J Dusser E Umeno P D Graf T Djokic D B Borson J A Nadel 《Journal of applied physiology》1988,65(6):2585-2591
To determine whether neutral endopeptidase (NEP), also called enkephalinase (EC 3.4.24.11), modulates the effects of exogenous and endogenous tachykinins in vivo, we studied the effects of aerosolized phosphoramidon, a specific NEP inhibitor, on the responses to aerosolized substance P (SP) and on the atropine-resistant response to vagus nerve stimulation (10 V, 5 ms for 20 s) in guinea pigs. SP alone (10(-7) to 10(-4) M; each concentration, 7 breaths) caused no change in total pulmonary resistance (RL, P greater than 0.5). Phosphoramidon (10(-4) M, 90 breaths) caused no change either in base-line RL (P greater than 0.5) or in the response to aerosolized acetylcholine (P greater than 0.5). However, in the presence of phosphoramidon, SP (7 breaths) produced a concentration-dependent increase in RL at concentrations greater than or equal to 10(-5) M (P less than 0.001). Phosphoramidon (10(-7) to 10(-4) M; each concentration, 90 breaths) induced a concentration-dependent potentiation of SP-induced bronchoconstriction (10(-4) M, 7 breaths; P less than 0.01). Vagus nerve stimulation (0.5-3 Hz), in the presence of atropine, induced a frequency-dependent increase in RL (P less than 0.001). Phosphoramidon potentiated the atropine-resistant responses to vagus nerve stimulation (P less than 0.001) at frequencies greater than 0.5 Hz. The tachykinin antagonist [D-Arg1,D-Pro2,D-Trp7,9,Leu11]-substance P abolished the effects of phosphoramidon on the atropine-resistant response to vagus nerve stimulation (2 Hz, P less than 0.005). NEP-like activity in tracheal homogenates of guinea pig was inhibited by phosphoramidon with a concentration producing 50% inhibition of 5.3 +/- 0.8 nM.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
4.
5.
6.
Gojgic-Cvijovic GD Milic JS Solevic TM Beskoski VP Ilic MV Djokic LS Narancic TM Vrvic MM 《Biodegradation》2012,23(1):1-14
This article presents a study of the efficiency and degradation pattern of samples of petroleum sludge and polluted sandy
soil from an oil refinery. A bacterial consortium, consisting of strains from the genera Pseudomonas, Achromobacter, Bacillus and Micromonospora, was isolated from a petroleum sludge sample and characterized. The addition of nitrogen and phosphorus nutrients and a chemical
surfactant to both the samples and bioaugmentation to the soil sample were applied under laboratory conditions. The extent
of biodegradation was monitored by the gravimetric method and analysis of the residual oil by gas chromatography. Over a 12-week
experiment, the achieved degree of TPH (total petroleum hydrocarbon) degradation amounted to 82–88% in the petroleum sludge
and 86–91% in the polluted soil. Gas chromatography–mass spectrometry was utilized to determine the biodegradability and degradation
rates of n-alkanes, isoprenoids, steranes, diasteranes and terpanes. Complete degradation of the n-alkanes and isoprenoids fractions occurred in both the samples. In addition, the intensities of the peaks corresponding to
tricyclic terpenes and homohopanes were decreased, while significant changes were also observed in the distribution of diasteranes
and steranes. 相似文献
7.
Laetitia Sabatier Jelena Djokic Dirk Hubmacher Dzaner Dzafik Valentin Nelea Dieter P. Reinhardt 《FEBS letters》2014
Fibrillins form multifunctional microfibrils in most connective tissues. Deficiencies in fibrillin assembly can result in fibrillinopathies, such as Marfan syndrome. We demonstrate the presence of heparin/heparan sulfate binding sites in fibrillin-2 and -3. Multimerization of all three fibrillins drastically increased the apparent affinity of their interaction with heparin/heparan sulfate. Surprisingly, contrary to other reports heparin/heparan sulfate strongly inhibited homo- and heterotypic N-to-C-terminal fibrillin interactions. These data suggest that heparin/heparan sulfate controls the formation of microfibrils at the bead interaction stage. 相似文献
8.
Djokic T. D.; Dusser D. J.; Borson D. B.; Nadel J. A. 《Journal of applied physiology》1989,66(5):2338-2343
To determine the role of endogenous neutral endopeptidase (NEP) (also called enkephalinase, EC 3.4.24.11) in regulating neurotensin-induced airway contraction, we used phosphoramidon, a specific NEP inhibitor, in the guinea pig. In studies in vitro, neurotensin and the COOH-terminal fragment neurotensin-(8-13) contracted strips of bronchial smooth muscle in a concentration-dependent fashion (P less than 0.001). In contrast, the NH2-terminal fragment neurotensin-(1-11) and the COOH-terminal fragment neurotensin-(12-13), the main fragments of neurotensin hydrolysis by NEP, had no effect. Phosphoramidon (10(-5) M) did not change resting tension but shifted the concentration-response curves to neurotensin to lower concentrations (P less than 0.001), whereas inhibitors of kininase II, aminopeptidases, serine proteases, and carboxypeptidase N were without effect. Removing the epithelium increased the contractile response to neurotensin (P less than 0.001), and phosphoramidon further increased the response to neurotensin in these tissues (P less than 0.001). Similar results were obtained in studies in vivo using aerosolized neurotensin and phosphoramidon. These results suggest that endogenous NEP in the airways modulates the effects of neurotensin on airway smooth muscle contraction by inactivating the peptide. 相似文献
9.
10.
Djokic L Narancic T Nikodinovic-Runic J Savic M Vasiljevic B 《Applied microbiology and biotechnology》2011,91(4):1227-1238
Four new Gram-positive, phenol-degrading strains were isolated from the rhizospheres of endemorelict plants Ramonda serbica and Ramonda nathaliae known to exude high amounts of phenolics in the soil. Isolates were designated Bacillus sp. PS1, Bacillus sp. PS11, Streptomyces sp. PS12, and Streptomyces sp. PN1 based on 16S rDNA sequence and biochemical analysis. In addition to their ability to tolerate and utilize high amounts
of phenol of either up to 800 or up to 1,400 mg l−1 without apparent inhibition in growth, all four strains were also able to degrade a broad range of aromatic substrates including
benzene, toluene, ethylbenzene, xylenes, styrene, halogenated benzenes, and naphthalene. Isolates were able to grow in pure
culture and in defined mixed culture on phenol and on the mixture of BTEX (benzene, toluene, ethylbenzene, and xylenes) compounds
as a sole source of carbon and energy. Pure culture of Bacillus sp. PS11 yielded 1.5-fold higher biomass amounts in comparison to mixed culture, under all conditions. Strains successfully
degraded phenol in the soil model system (2 g kg−1) within 6 days. Activities of phenol hydroxylase, catechol 1,2-dioxygenase, and catechol 2,3-dioxygenase were detected and
analyzed from the crude cell extract of the isolates. While all four strains use ortho degradation pathway, enzyme indicative of meta degradation pathway (catechol 2,3-dioxygenase) was also detected in Bacillus sp. PS11 and Streptomyces sp. PN1. Phenol degradation activities were induced 2 h after supplementation by phenol, but not by catechol. Catechol slightly
inhibited activity of catechol 2,3-dioxygenase in strains PS11 and PN1. 相似文献