Home About us Contact
|
Home About us Contact | ||
|
|
||
Only Compound (only + compound)
Selected AbstractsA brief introduction to cell-penetrating peptidesJOURNAL OF MOLECULAR RECOGNITION, Issue 5 2003Pontus Lundberg Abstract Cell membranes act as protective walls to exclude most molecules that are not actively imported by living cells. This is an efficient way for a cell to prevent uncontrolled influx or efflux of solutes, which otherwise would be harmful to it. Only compounds within a narrow range of molecular size, polarity and net charge are able to diffuse effectively through cell membranes. In order to overcome this barrier for effective delivery of membrane-impermeable molecules, several chemical and physical methods have been developed. These methods, e.g. electroporation, and more recent methods as cationic lipids/liposomes, have been shown to be effective for delivering hydrophobic macromolecules. The drawbacks of these harsh methods are, primarily, the unwanted cellular effects exerted by them, and, secondly, their limitation to in vitro applications. The last decade's discovery of cell-penetrating peptides translocating themselves across cell membranes of various cell lines, along with a cargo 100-fold their own size, via a seemingly energy-independent process, opens up the possibility for efficient delivery of DNA, antisense peptide nucleic acids, oligonucleotides, proteins and small molecules into cells both in vitro and in vivo. Copyright © 2003 John Wiley & Sons, Ltd. [source] Synthesis of L -Furanomycin and Its Analogues via Furoisoxazolines,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2005Peter J. Zimmermann Abstract The 1,3-dipolar cycloaddition of nitrile oxides and 2-methylfuran has provided suitable precursors for ,-amino acids such as L -furanomycin (1) that contain a dihydrofuran ring. By using a chiral nitrile oxide derived from D -glyceraldehyde, the enantiomerically pure furoisoxazolines 9 and 10 were obtained. Owing to the bicyclic, bowl-shaped structure of furoisoxazoline 9 highly stereoselective additions were feasible, in particular, the epoxidation of 9 with dimethyldioxirane provided the required (5'S) configuration in 1 after epoxide reduction. Hydroboration of 9 led to the (5'R) epimer 2 and nucleophilic addition of a methyl Grignard reagent to epoxyfuroisoxazoline 11 gave rise to 5'-methylfuranomycin (3). Further, catalytic hydrogenation of the dihydrofuran intermediate 22, derived from 11, afforded the tetrahydrofuranyl derivative 31 from which dihydrofuranomycin (4) was obtained in enantiomerically pure form. The biological activities of these ,-amino acids showed an extremely narrow structure,activity profile, the natural product being the only compound of this series with high activities. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Pharmaceuticals and Other Organic Waste Water Contaminants Within a Leachate Plume Downgradient of a Municipal LandfillGROUND WATER MONITORING & REMEDIATION, Issue 2 2004Kimberlee K. Barnes Ground water samples collected from the Norman Landfill research site in central Oklahoma were analyzed as part of the U.S. Geological Survey (USGS) Toxic Substances Hydrology Program's national reconnaissance of pharmaceuticals and other organic waste water contaminants (OWCs) in ground water. Five sites, four of which are located downgradient of the landfill, were sampled in 2000 and analyzed for 76 OWCs using four research methods developed by the USGS. OWCs were detected in water samples from all of the sites sampled, with 22 of the 76 OWCs being detected at least once. Cholesterol (a plant and animal steroid), was detected at all five sites and was the only compound detected in a well upgradient of the landfill. N,N-diethyltoluamide (DEBT used in insect repellent) and tri(2-chloroethyl) phosphate (fire-retardant) were detected in water samples from all four sites located within the landfill-derived leachate plume. The sites closest to the landfill had more detections and greater concentrations of each of the detected compounds than sites located farther away. Detection of multiple OWCs occurred in the four sites located within the leachate plume, with a minimum of four and a maximum of 17 OWCs detected. Because the landfill was established in the 1920s and closed in 1985, many compounds detected in the leachate plume were likely disposed of decades ago. These results indicate the potential for long-term persistence and transport of some OWCs in ground water. [source] Sherry wine vinegar: physicochemical changes during the acetification processJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2001L Morales Abstract The quality of a wine vinegar is determined by the raw wine substrate and the acetification process employed in its production. Attempts to characterise vinegars have been based on these two features, along with variables such as total extract, glycerol, organic acids, volatile compounds and phenolic composition. When the final products are analysed, it is difficult to evaluate to what extent quality differences are due to the raw material or to differences in production methods, so it is necessary to determine the influence of each feature separately. The present work focuses on monitoring physicochemical changes during the acetification of sherry wine by submerged culture. ANOVA showed significant differences for ethanol, acetic and lactic acids and some volatile compounds (methanol, 1-propanol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, acetoin, acetaldehyde, ethyl acetate and ethyl lactate). However, no statistical changes were found for phenolic compounds during acetification. The phenolic composition of the final product was determined by the substrate employed. In addition, the influence of cycle duration on the chemical composition was studied; the only compound affected by this factor was 2-methyl-1-butanol. © 2001 Society of Chemical Industry [source] Effect of Binary Combinations of Selected Toxic Compounds on Growth and Fermentation of Kluyveromyces marxianusBIOTECHNOLOGY PROGRESS, Issue 3 2004Jose M. Oliva The inhibitory effects of various lignocellulose degradation products on glucose fermentation by the thermotolerant yeast Kluyveromycesmarxianus were studied in batch cultures. The toxicity of the aromatic alcohol catechol and two aromatic aldehydes (4-hydroxybenzaldehyde and vanillin) was investigated in binary combinations. The aldehyde furfural that usually is present in relatively high concentration in hydrolyzates from pentose degradation was also tested. Experiments were conducted by combining agents at concentrations that individually caused 25% inhibition of growth. Compared to the relative toxicity of the individual compounds, combinations of furfural with catechol and 4-hydroxybenzaldehyde were additive (50% inhibition of growth). The other binary combinations assayed (catechol with 4-hydroxybenzaldehyde, and vanillin with catechol, furfural, or 4-hydroxybenzaldehyde) showed synergistic effect on toxicity and caused a 60,90% decrease in cell mass production. The presence of aldehydes in the fermentation medium strongly inhibited cell growth and ethanol production. Kluyveromyces marxianusreduces aldehydes to their corresponding alcohols to mitigate the toxicity of these compounds. The total reduction of aldehydes was needed to start ethanol production. Vanillin, in binary combination, was dramatically toxic and was the only compound for which inhibition could not be overcome by yeast strain assimilation, causing a 90% reduction in both cell growth and fermentation. [source] | ||||||||||