Search results for "Cero"
showing 10 items of 691 documents
Polyunsaturated fatty acids in the modulation of T-cell signalling
2009
n-3 polyunsaturated fatty acids (PUFA) have been shown to modulate immune responses. These agents, being considered as adjuvant immunosuppressants, have been used in the treatment of various inflammatory and autoimmune diseases. However, the molecular mechanisms of action of n-3 PUFA-induced immunosuppressive effects are not well-understood. Since exogenous n-3 PUFA, under in vitro and in vivo conditions, are efficiently incorporated into T-cell plasma membranes, a number of recent studies have demonstrated that these agents may modulate T-cell signalling. In this review, the interactions of n-3 PUFA with the second messenger cascade initiated during early and late events of T-cell activati…
Mesogen-Initiated Linear Polyglycerol Isomers: The Ordering Effect of a Single Cholesterol Unit on “Sticky” Isotropic Chains
2011
Synthesis, thermal properties, and the liquid crystalline (LC) order of polymers consisting of a single mesogenic cholesterol unit and flexible, linear polyglycerol (PG) or poly(glyceryl glycerol) (PGG) chains have been investigated. Incorporation of the single mesogen has been achieved by using cholesterol directly as an initiator for the oxyanionic ring-opening polymerization (ROP) of ethoxyethyl glycidyl ether (EEGE) or isopropylidene glyceryl glycidyl ether (IGG). The controlled polymerization allowed the synthesis of a series of peculiar rod–coil type polyethers with molecular weights of 600–2300 g/mol, representing a degree of polymerization (DPn) of 4–30 for both PG and PGG with the …
Poly(1,2-glycerol carbonate): A Fundamental Polymer Structure Synthesized from CO2 and Glycidyl Ethers
2013
The functional, aliphatic poly(1,2-glycerol carbonate) as a fundamental, simple polymer structure based on glycerol and CO2 was prepared by combination of glycidyl ether monomers with carbon dioxide via two different approaches. The material was obtained by two-step procedures either via copolymerization of (i) ethoxy ethyl glycidyl ether (EEGE) or (ii) benzyl glycidyl ether (BGE) with CO2, followed by removal of the respective protecting groups via acidic cleavage for (i) and hydrogenation for (ii). The resulting protected polycarbonate structures and the targeted poly(1,2-glycerol carbonate) were investigated with 1H NMR and 13C NMR spectroscopy as well as 2D-NMR methods. Removal of both …
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…
Evidence for the involvement of acylglycerides on chitin synthetase activity inCandida albicans
1991
The effect of a lipase activity (EC 3.1.1.3) on the chitin synthetase from Candida albicans has been studied, both on the active and the trypsin activated enzyme. Removal of fatty acids from acylglycerides by lipase has an inhibitory effect on the activity as well as on the ‘in vitro’ activation process by trypsin in the membrane-bound enzyme and in the chitosomes. This would indicate that an adequate lipid environment is required for both the activation process and proper function of the synthetase activity.
Enzyme-mediated enantioselective acylation of secondary amines in organic solvents
1991
Abstract Porcine pancreatic lipase (PPL) and lipase Amano P catalyze the enantioselective acylation of cyclic 1,2- and 1,3-amino alcohol derivatives in organic solvents. The enatiomeric excesses (ee′s) were shown to depend on the enzyme, reaction time, temperature and type of substrate.
Study of a lipase from Candida rugosa Diddens and Lodder
1993
Lipasic system of Candida rugosa (CBS 613) strain was studied. The enzyme was purified in one step by hydrophobic chromatography. The properties of this lipase were determined. It is an oligomeric enzyme composed of five identical monomers of 46 kg · mol−1. Its optimum reaction conditions are pH = 7 and temperature = 40°C. This enzyme presents a rapid thermal denaturation and then a more stable form. It is a cell-bound lipase which is induced by triacyl glycerols. This enzyme presents a high specificity for external positions on glycerol. Unterschung einer Lipase aus Candida rugosa Diddens und Lodder Die Reinigung einer Lipase aus Candida rugosa (CBS 613) wurde in einer einzigen Stufe durch…
Lipase-enhanced activity in flavour ester reactions by trapping enzyme conformers in the presence of interfaces
1998
In order to improve the lipase-catalyzed synthesis of flavour esters, we have used the reported strategy of interfacial activation-based molecular (bio)imprinting [Mingarro et al. 1995. Proc. Natl. Acad. Sci. U.S.A. 92: 3308], later called trapping in the presence of amphiphile interfaces (TPI) [Mingarro et al. 1996. Biochemistry 35: 9935]. Five lipases of fungal and mammalian origin typically used for esterification process have been explored to improve production by TPI treatment. A marked enhancement of enzymatic activity has been observed in all TPI-treated lipases assayed and the activation factor obtained was up to 90-fold. The dependence on chain length of acyl donors in the esterifi…
Polymer ester von sären des phosphors, 7. Polymerisation des 1-oxo-2,6,7-trioxa-1-phosphabicyclo[2.2.1]heptans
1981
1-Oxo-2,6,7-trioxa-1-phosphabicyclo[2.2.1]heptane is transformed in situ (prepared from trimethyl phosphite and glycerol) at −78°C in the presence of a trace of water into a crosslinked polymer containing constitutional repeating units with 5- and 6-membered rings. The reaction with reagents containing hydroxyl groups (water, acetic acid, alcohol) leads to the degradation of the network with the formation of soluble fragments with Pn = 35–50. This reactivity and the possibility to obtain other derivatives from the fragments make this polymer a carrier for pharmacologically active polymers with the advantage of decomposing only into the innocuous components phosphoric acid and glycerol.
Der Verteilungsraum von physikalisch gelöstem Sauerstoff in wäßrigen Lösungen organischer Substanzen / The Distribution Space of Physically Dissolved…
1976
Abstract In order to evaluate the distribution of molecular oxygen in biological systems, the oxygen solubility (ml/ml atm) at 37 °C in aqueous solutions of thirty organic substances with different concentrations was measured by the classical Van Slyke principle. The oxygen solubility always (with the exception of hemoglobin) decreases exponentially with increasing concentration of the respective substance. In all cases this behavior is described highly significant by a simple empiric exponential function, when the substance concentration as well as the oxygen solubility of pure water is given. The influence of one substance on oxygen solubility contributes additively to the over-all solubi…