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Several Amino Acids (several + amino_acids)
Selected AbstractsMechanisms of cytoprotective effect of amino acids on local toxicity caused by sodium laurate, a drug absorption enhancer, in intestinal epitheliumJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2002Yoko Endo Abstract Several amino acids, including L -glutamine (L -Gln), were found to protect the intestinal epithelial cells from the local toxicity caused by a drug absorption enhancer, sodium laurate (C12), in our previous study. To develop more efficient and safer formulations for enhancing drug absorption, the mechanisms of cytoprotection by amino acids were studied using rats and Caco-2 cells. Four amino acids, including L -Gln, could generally maintain the absorption-promoting action of C12, although taurine tended to attenuate it. Three amino acids, except for L -Gln, significantly suppressed the decrease in the transepithelial electrical resistance caused by C12. Quercetin, an inhibitor for biosynthesis of heat shock protein 70 (HSP70), masked only the protective effect of L -Gln in both rat large intestine and Caco-2 cells. Western blot analysis indicated clearly that HSP70 is induced extensively only by the addition of L -Gln in both rat large-intestinal cells and Caco-2 cells. C12 was found to increase the intracellular concentration of Ca2+ ([Ca2+]i) remarkably, and amino acids, especially L -arginine, L -methionine, and taurine, significantly attenuated the increase in [Ca2+]i caused by C12. Furthermore, although C12 stimulated the release of histamine, an inflammatory mediator, from rat large-intestinal tissue, amino acids were also found to suppress the release of histamine enhanced by C12. The results in the present study showed that an induction of HSP70, a decrease in [Ca2+]i elevated by C12, and a suppression of histamine release stimulated by C12 should be involved in the mechanisms behind the cytoprotective action of amino acids against the local toxicity caused by C12. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:730,743, 2002 [source] Amino acids and glycine ethyl ester as new crystallization reagents for lysozymeACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2010Len Ito Several amino acids and their derivatives are prominent additives in the field of protein chemistry. This study reports the use of charged amino acids and glycine ethyl ester as precipitants in protein crystallization, using hen egg-white lysozyme (HEWL) as a model. A discussion of the crystallization of HEWL using these reagents as precipitating agents is given. [source] Application of Hadamard transformation to MEKCELECTROPHORESIS, Issue 3 2007Kazuki Hata Abstract The Hadamard transform (HT) technique, which permits the S/N in CE to be improved, was applied to MEKC. Multiple sample injection of fluorescent analytes according to a Hadamard code sequence was performed using an optically gated sample injection technique, in which a sample plug was produced based on photodegradation by irradiation with an intense laser beam. The capillary and reservoirs were filled with a sample solution containing buffer components and SDS as a pseudostationary phase. A preliminary study confirmed that fluorescein ion could be photobleached in the presence of SDS. The optically gated sample injection technique was then applied to multiple sample injection, based on a Hadamard matrix. The S/N in the electropherogram obtained by HT-MEKC was improved substantially compared to that obtained by a single injection method. When the technique was applied to the separation of several amino acids labeled with FITC, the S/N ratio for each amino acid was enhanced, without any evidence of degradation in separation resolution. Moreover, HT-MEKC was applied to the analysis of amino acids contained in a Japanese beverage, resulting in improved S/Ns for the amino acids. [source] ,-Cyclodextrin as novel chiral probe for enantiomeric separation by electromigration methodsELECTROPHORESIS, Issue 21 2006Dorothee Wistuba Abstract Native ,-CD has been employed as chiral selector in CE and MEKC. To investigate the potential of the enantiodiscriminating properties of ,-CD, negatively charged 5-dimethylamino-1-naphthalene-sulfonyl (dansyl)-, 2,4-dinitrophenyl (DNP)- and FMOC-derivatives of several amino acids, 1,1'-binaphthyl-2,2'-diylhydrogenphosphate, flavanones and three positively charged drugs have been selected as testing samples. Enantioresolution factors up to 4.82 have been observed. The results were compared with those achieved by the conventional running buffer additives ,-, ,- and ,-CDs. For several examples a steady increase of enantioresolution with increasing degree of oligomerization has been detected. [source] Lack of CbrB in Pseudomonas putida affects not only amino acids metabolism but also different stress responses and biofilm developmentENVIRONMENTAL MICROBIOLOGY, Issue 6 2010Cristina I. Amador Summary The CbrAB two-component system has been described in certain species of Pseudomonads as a global regulatory system required for the assimilation of several amino acids (e.g. histidine, proline or arginine) as carbon or carbon and nitrogen sources. In this work, we used global gene expression and phenotypic analyses to characterize the roles of the CbrAB system in Pseudomonas putida. Our results show that CbrB is involved in coordination with the nitrogen control system activator, NtrC, in the uptake and assimilation of several amino acids. In addition, CbrB affects other carbon utilization pathways and a number of apparently unrelated functions, such as chemotaxis, stress tolerance and biofilm development. Based on these new findings, we propose that CbrB is a high-ranked element in the regulatory hierarchy of P. putida that directly or indirectly controls a variety of metabolic and behavioural traits required for adaptation to changing environmental conditions. [source] Acrodermatitis Enteropathica-like Dermatosis Associated with Ornithine Transcarbamylase DeficiencyPEDIATRIC DERMATOLOGY, Issue 4 2007José C. Pascual M.D. Ornithine transcarbamylase deficiency is the most frequent urea cycle disorder. It is a hereditary-X-linked disease with over 150 mutations described (1).Ornithine transcarbamylase deficiency causes vomiting, lethargy, hyperventilation, and even death, mainly in the neonatal period (2). Ammonia, an extremely toxic molecule for the organism, is generated during protein catabolism and is accumulated in patients with this deficiency. Part of the treatment consists of a low-protein diet, to avoid hyperammonemia episodes, which can even have a fatal outcome. Patients can become deficient in several amino acids, either through the low-protein diet or directly through the primary enzyme deficiency; this in turn can cause an acrodermatitis enteropathica-like dermatosis. [source] Prolonging Cell-Free Protein Synthesis by Selective Reagent AdditionsBIOTECHNOLOGY PROGRESS, Issue 3 2000Dong-Myung Kim Factors causing the early cessation of protein synthesis have been studied in a cell-free system from Escherichia coli. We discovered that phosphoenol pyruvate (PEP), the secondary energy source for ATP regeneration, and several amino acids are rapidly degraded during the cell-free protein synthesis reaction. The degradation of such compounds takes place even in the absence of protein synthesis. This degradation severely reduces the capacity for protein synthesis. The lost potency was completely recovered when the reaction mixture was supplied with additional PEP and amino acids. Of the 20 amino acids, only arginine, cysteine, and tryptophan were required to restore system activity. Through repeated additions of PEP, arginine, cysteine,and tryptophan, the duration of protein synthesis was greatly extended. In this fed-batch reaction, after a 2 h incubation, the level of cell-free synthesized chloramphenicol acetyl transferase (CAT) reached 350 ,g/mL, which is 3.5 times the yield of the batch reaction. Addition of fresh magnesium further extended the protein synthesis. As a result, through coordinated additions of PEP, arginine, cysteine, tryptophan, and magnesium, the final concentration of cell-free synthesized CAT increased more than 4-fold compared to a batch reaction. SDS-PAGE analysis of such a fed-batch reaction produced an obvious band of CAT upon Coomassie Blue staining. [source] Thermal Wet Decomposition of Prussian Blue: Implications for Prebiotic ChemistryCHEMISTRY & BIODIVERSITY, Issue 9 2009Marta Ruiz-Bermejo Abstract The complex salt named Prussian Blue, Fe4[Fe(CN)6]3,15,H2O, can release cyanide at pH>10. From the point of view of the origin of life, this fact is of interest, since the oligomers of HCN, formed in the presence of ammonium or amines, leads to a variety of biomolecules. In this work, for the first time, the thermal wet decomposition of Prussian Blue was studied. To establish the influence of temperature and reaction time on the ability of Prussian Blue to release cyanide and to subsequently generate other compounds, suspensions of Prussian Blue were heated at temperatures from room temperature to 150° at pH,12 in NH3 environment for several days. The NH3 wet decomposition of Prussian Blue generated hematite, , -Fe2O3, the soluble complex salt (NH4)4[Fe(CN6)],1.5,H2O, and several organic compounds, the nature and yield of which depend on the experimental conditions. Urea, lactic acid, 5,5-dimethylhydantoin, and several amino acids and carboxylic acids were identified by their trimethylsilyl (TMS) derivatives. HCN, cyanogen (C2N2), and formamide (HCONH2) were detected in the gas phase by GC/MS analysis. [source] | |||||||||||||