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Defined Amount (defined + amount)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Development of a Supported Ionic Liquid Phase (SILP) Catalyst for Slurry-Phase Friedel,Crafts Alkylations of Cumene

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009
J. Joni
Abstract A supported ionic liquid phase (SILP) catalyst material has been developed based on a silica support coated with an acidic chloroaluminate ionic liquid. Compared to the results in a liquid-liquid biphasic reaction these materials showed in the isopropylation of cumene a clearly different selectivity which was found to be related to a reduction of the ionic liquid's acidity by the untreated silica support. By pretreating the support with a defined amount of ionic liquid for neutralization and removal of surface hydroxy groups, a well defined, very active and also very selective SILP catalyst for slurry phase Friedel,Crafts alkylation was obtained. [source]

Biomass recycling from a riboflavin cultivation with B. subtilis: Lysis, extract production and testing as substrate in riboflavin cultivation

BIOTECHNOLOGY & BIOENGINEERING, Issue 6 2006
Karlheinz Bretz
Abstract Autolysis of riboflavin-producing B. subtilis can be induced by pH, lack of carbon source, and the buffer system. Stress factors like temperature shift or oxygen dearth enhance the autolysis process. After cultivation of a riboflavin-producing strain, the pH of the whole culture broth was adjusted to 6.5,7.5. At a temperature of 40°C, autolysis started after 1 h. Adding a defined amount of commercially available endo- and exo-proteases enhanced both auto- and proteo-lysis. Optimization of endo- and exo-protease concentrations and of the time increased the degree of proteolysis. Additionally, the amount of DNA and Protein trapped in the riboflavin crystals could be significantly reduced by autolysis. After autolysis, the cultivation broth was centrifuged and the supernatant was cross-flow filtrated with a cut off of 10 kDa. Using this autolysate instead of yeast extract as a medium component for riboflavin production with B. subtilis, a riboflavin yield of 77% was obtained in comparison with the standard cultivation on yeast extract. © 2006 Wiley Periodicals, Inc. [source]

Novel glycosaminoglycan mimetic (RGTA, RGD120) contributes to enhance skeletal muscle satellite cell fusion by increasing intracellular Ca2+ and calpain activity

JOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2005
M. Zimowska
Glycosaminoglycans (GAG) are classes of molecules that play an important role in cellular processes. The use of GAG mimetics called regenerating agent (RGTA) represents a tool to investigate the effect of GAG moiety on cellular behavior. A first member of the RGTA family (RG1192), a dextran polymers with defined amounts of sulfate, carboxymethyl, as well as hydrophobic groups (benzylamide), was shown to stimulate skeletal muscle repair after damage and myoblast differentiation. To obtain a comprehensive insight into the mechanism of action of GAG mimetics, we investigated the effect on myoblast differentiation of a novel RGTA, named RGD120, which was devoid of hydrophobic substitution and had ionic charge similar to heparin. Myoblasts isolated from adult rat skeletal muscles and grown in primary cultures were used in this study. We found that chronic treatment with RGD120 increased the growth of adult myoblasts and induced their precocious fusion into myotubes in vitro. It also partially overcame the inhibitory effect of the calpain inhibitor N -acetyl-leu-leu-norleucinal (ALLN) on these events. Western blot and zymography analyses revealed that milli calpain was slightly increased by RGD120 chronic treatment. In addition, using fluorescent probes (Indo-1 and Boc-leu-met-MAC), we demonstrated that RGD120 added to prefusing myoblast cultures accelerates myoblast fusion into myotubes, induced an increase of cytosolic free calcium concentration, and concomitantly an increase of intracellular calpain protease activity. Altogether, these results suggested that the efficiency of RGD120 in stimulating myogenesis might be in part explained through its effect on calcium mobilization as well as on the calpain amount and activity. © 2005 Wiley-Liss, Inc. [source]

Agar sublimation test for the in vitro determination of the antifungal activity of morpholine derivatives

MYCOSES, Issue 5-6 2004
A. Polak
Antimykotische Aktivität; Morpholine; Sublimation Summary We studied the in vitro antifungal activities of a wide range of antimycotic agents, including amorolfine, terbinafine, naftifine, five morpholine derivatives, ciclopiroxolamine, bifonazole, clotrimazole, ketoconazole, itraconazole, fluconazole, voriconazole, flucytosine, amphotericin B, nystatin, and caspofungin, against Candida albicans and Trichophyton rubrum by conventional agar diffusion tests and by a novel sublimation method. For the sublimation method, 6 mm filter paper disks were soaked with defined amounts of antimycotic drugs, air dried, placed in the center of the lids of 9 cm Petri dishes, and incubated upside down with inoculated agar plates 10 mm above the disks. The conventional disk diffusion tests produced inhibition zones as previously described. The disk sublimation tests produced large inhibition zones with amorolfine, five amorolfine derivatives, and terbinafine, but with none of the other antifungal agents. Possible therapeutic advantages of agents, which are able to overcome air cavities in mycotic lesions, e.g. in onychomycosis, are discussed. Zusammenfassung Wir untersuchten in vitro die antimykotische Aktivität eines breiten Spektrums von Antimykotika, einschließlich Amorolfin, Terbinafin, Naftifin, fünf Morpholin-Derivaten, Ciclopiroxolamin, Bifonazol, Clotrimazol, Ketoconazol, Itraconazol, Fluconazol, Voriconazol, 5-Fluorcytosin, Amphotericin B, Nystatin und Caspofungin, gegenüber Candida albicans und Trichophyton rubrum mit konventionellen Agardiffusionstesten und mit einer neuartigen Sublimationsmethode. Für die Sublimationsmethode wurden 6 mm-Filterpapier-Blättchen mit definierten Mengen von Antimykotika getränkt, luftgetrocknet, in die Mitte der Deckel von 9 cm-Petrischalen gelegt und mit der inokulierten Agarplatte 10 mm über den Blättchen umgedreht inkubiert. Die konventionellen Agardiffusionsteste produzierten Hemmhöfe wie früher beschrieben. Die Blättchen-Sublimationsteste produzierten große Hemmhöfe mit Amorolfin, fünf Morpholin-Derivaten und Terbinafin, nicht jedoch mit den anderen Antimykotika. Mögliche therapeutische Vorteile von Agentien, die luftgefüllte Hohlräume in mykotischen Läsionen überbrücken können, z. B. im Nagel bei Onychomykose, werden diskutiert. [source]