Search results for "PLC"
showing 10 items of 242 documents
The yeast inositol monophosphatase is a lithium- and sodium-sensitive enzyme encoded by a non-essential gene pair
1999
Inositol monophosphatases (IMPases) are lithium-sensitive enzymes that participate in the inositol cycle of calcium signalling and in inositol biosynthesis. Two open reading frames (YHR046c and YDR287w) with homology to animal and plant IMPases are present in the yeast genome. The two recombinant purified proteins were shown to catalyse inositol-1-phosphate hydrolysis sensitive to lithium and sodium. A double gene disruption had no apparent growth defect and was not auxotroph for inositol. Therefore, lithium effects in yeast cannot be explained by inhibition of IMPases and inositol depletion, as suggested for animal systems. Overexpression of yeast IMPases increased lithium and sodium toler…
Automated multi-dimensional liquid chromatography
2004
A comprehensive on-line sample clean-up with an integrated two-dimensional HPLC system was developed for the analysis of natural peptides. Samples comprised of endogenous peptides with molecular weights up to 20 kDa were generated from human hemofiltrate (HF) obtained from patients with chronic renal failure. The (poly-)peptides were separated using novel silica-based restricted access materials with strong cation-exchange functionalities (SCX-RAM). The size-selective sample fractionation step is followed by cation-exchange chromatography as the first dimension. The subsequent second dimension of separation is based on hydrophobic interaction using four parallel short reversed-phase (RP) co…
Particle packed columns and monolithic columns in high-performance liquid chromatography-comparison and critical appraisal
2007
The review highlights the fundamentals and the most prominent achievements in the field of high-performance liquid chromatography (HPLC) column development over a period of nearly 50 years. After a short introduction on the structure and function of HPLC columns, the first part treats the major steps and processes in the manufacture of a particle packed column: synthesis and control of particle morphology, sizing and size analysis, packing procedures and performance characterization. The next section is devoted to three subjects, which reflect the recent development and the main future directions of packed columns: minimum particle size of packing, totally porous vs. core/shell particles an…
RpeakChrom: Novel R package for the automated characterization and optimization of column efficiency in high-performance liquid chromatography analys…
2017
Characterization of chromatographic columns using the traditional van Deemter method is limited by the necessity of calculating extra-column variance, issue particularly relevant when modeling asymmetrical peaks eluted from monolithic columns. A novel R package that implements Parabolic Variance Modified Gaussian approach for accurate peak modeling, van Deemter equation and two alternatives approaches, based on van Deemter, has been developed to calculate the height equivalent to a theoretical plate (HETP). To assess package capabilities conventional packed reverse-phase and monolithic HPLC columns were characterized. Peaks eluted from the monolithic column showed a high value of factor asy…
Comparison of monolithic and microparticulate columns for reversed-phase liquid chromatography of tryptic digests of industrial enzymes in cleaning p…
2011
Abstract Enzymes of several classes used in the formulations of cleaning products were characterized by trypsin digestion followed by HPLC with UV detection. A polymeric monolithic column (ProSwift) was used to optimize the separation of both the intact enzymes and their tryptic digests. This column was adequate for the quality control of raw industrial enzyme concentrates. Then, monolithic and microparticulate columns were compared for peptide analysis. Under optimized conditions, the analysis of tryptic digests of enzymes of different classes commonly used in the formulation of cleaning products was carried out. Number of peaks, peak capacity and global resolution were obtained in order t…
Phenolic compounds of herbal infusions obtained from some species of the Lamiaceae family
2018
Abstract The present investigation was to estimate the total phenolic content and composition of flavonoids and hydroxycinnamic acids in herbal infusions obtained from aerial parts of three Lamiaceae species (Dracocephalum moldavica, Ocimum americanum and Satureja hortensis). The total phenolic content of herbal infusions was determined using a spectrophotometric method, whereas the individual phenolics were assessed by high-performance liquid chromatography (HPLC). The HPLC method was developed and validated. The total phenolic content was measured by applying the Folin-Ciocalteu method with reference to gallic acid. Results were in the range from 29.39 to 65.38 mg estimated as gallic acid…
SIMULTANEOUS DETERMINATION OF ATP, ITS METABOLITES AND NAD+ IN BLOOD BY HPLC WITH PHOTODIODE ARRAY DETECTOR
2013
SIMULTANEOUS DETERMINATION OF ATP, ITS METABOLITES AND NAD+ IN BLOOD BY HPLC WITH PHOTODIODE ARRAY DETECTOR Gueli Maria Concetta, Cusimano Vincenza, Lo Re Marianna, Giuseppe Salemi Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche (BioNEC), Università degli Studi di Palermo. Nucleotides are major high-energy phosphate carriers, subunits of nucleic acids and precursors for the synthesis of nucleotide cofactors such as NAD+ and SAM. The study of purine nucleotides metabolism is very important topic for a right understanding for the cellular life. Living cells rely on ATP for growth, differentiation, and response to physiological stimuli and environmental stress. We propose a fa…
ATP distribution and localization of mitochondria in Suberites domuncula (Olivi 1792) tissue
2011
SUMMARY The metabolic energy state of sponge tissue in vivo is largely unknown. Quantitative bioluminescence-based imaging was used to analyze the ATP distribution of Suberites domuncula (Olivi 1792) tissue, in relation to differences between the cortex and the medulla. This method provides a quantitative picture of the ATP distribution closely reflecting the in vivo situation. The obtained data suggest that the highest ATP content occurs around channels in the sponge medulla. HPLC reverse-phase C-18, used for measurement of ATP content, established a value of 1.62 μmol ATP g–1 dry mass in sponge medulla, as opposed to 0.04 μmol ATP g–1 dry mass in the cortex, thus indicating a specific and…
Wine metabolomic analysis : "chemical messages in a bottle"
2014
The main objective of this work was to develop non-targeted metabolomics analyses of bottled wines in order to decipher chemical informations from the time-related evolution of their composition. This original research was based on the hypothesis that, when analyzed, bottled wines would still hold chemical memories of envionmental parameters (vineyard management, oenological practices, climate, terroir…) at the moment of their elaboration, even after several years of ageing. A second hypothesis was that in order to anticipate the future evolution of the wine quality in terms of chemical composition, it is necessary to know what it was in the past. To that purpose, and for the first time in …
Analysis of Phenolic Compounds in Commercial
2019
Industrial hemp (Cannabis sativa L. Family Cannabaceae) contains a vast number of bioactive relevant compounds, namely polyphenols including flavonoids, phenolic acids, phenol amides, and lignanamides, well known for their therapeutic properties. Nowadays, many polyphenols-containing products made of herbal extracts are marketed, claiming to exert health-promoting effects. In this context, industrial hemp inflorescence may represent an innovative source of bioactive compounds to be used in nutraceutical formulations. The aim of this work was to provide a comprehensive analysis of the polyphenolic fraction contained in polar extracts of four different commercial cultivars (Kompoti, Tiborszal…