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Semiquantitative Determination (semiquantitative + determination)
Selected AbstractsSemiquantitative determination of Alicyclobacillus acidoterrestris in orange juice by reverse- transcriptase polymerase chain reaction and capillary electrophoresis , laser induced fluorescence using microchip technologyELECTROPHORESIS, Issue 21-22 2004Maribel Funes-Huacca Abstract The semiquantitative detection of Alicyclobacillus acidoterrrestris in orange juice by reverse-transcriptase polymerase chain reaction (RT-PCR) with a linear dynamic range of 2×105, 2 colony forming units (CFU)/mL in terms of cell count is described. Separation, detection, and quantification of the RT-PCR products were accomplished using the Agilent 2100 bioanalyzer in conjunction with the DNA 1000 LabChip kit. After 0 and 12 h of enrichment, it was possible to generate a linear standard curve between the amount of cells and amplicon concentration of RT-PCR and PCR products. Using this method, cell diminution was verified in samples of orange juice treated with a natural inhibitor (Sapindus saponaria), determining the persistence of viable cells. Semiquantitative RT-PCR using the Agilent 2100 bioanalyzer is a potentially useful approach for rapid in vitro determination of A. acidoterrestris and monitoring of inhibitor susceptibility for the orange juice-producing industry. [source] Pigments and proteins in green bacterial chlorosomes studied by matrix-assisted laser desorption ionization mass spectrometryFEBS JOURNAL, Issue 2 2000Sřren Persson We have used matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for mass determination of pigments and proteins in chlorosomes, the light-harvesting organelles from the photosynthetic green sulfur bacterium Chlorobium tepidum. By applying a small volume (1 µL) of a concentrated suspension of isolated chlorosomes directly to the target of the mass spectrometer we have been able to detect bacteriochlorophyll a and all the major homologs of bacteriochlorophyll c. The peak heights of the different bacteriochlorophyll c homologs in the MALDI spectra were proportional to peak areas obtained from HPLC analysis of the same sample. The same result was also obtained when whole cells of Chl. tepidum were applied to the target, indicating that MALDI-MS can provide a rapid method for obtaining a semiquantitative determination or finger-print of the bacteriochlorophyll homologs in a small amount of green bacterial cells. In addition to information on pigments, the MALDI spectra also contained peaks from chlorosome proteins. Thus we have been able with high precision to confirm the molecular masses of the chlorosome proteins CsmA and CsmE which have been previously determined by conventional biochemical and genetic methods, and demonstrate the presence of truncated versions of CsmA and CsmB. [source] In vivo release of the antimicrobial peptide hLF1-11 from calcium phosphate cement,JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2008Hein P. Stallmann Abstract We studied the release of human lactoferrin 1-11 (hLF1-11), a potent antimicrobial peptide, in an animal model. Calcium phosphate cement with 50 mg/g hLF1-11 was injected into the femoral canal of 12 rabbits. One, 3, and 7 days later, four animals were terminated, and the femora excised. Sections of bone and cement were removed for histological analysis. We used liquid chromatography-mass spectrometry/mass spectrometry for semiquantitative determination of the hLF1-11 concentration. Blood samples were drawn for leukocyte count and differentiation to identify a potential immunomodulating effect of hLF1-11. After an initial burst release, the hLF1-11 concentration in cement and bone decreased steadily. This in vivo release profile is consistent with earlier in vitro studies. Tissue ingrowth into the cement, without signs of inflammation or necrosis, was observed. Leukocytosis or a shift in leukocyte differentiation did not occur. The carrier released over 99% of the hLF1-11, resulting in peak concentrations at the cement,bone interface. This indicates that hLF1-11 could become a valuable prophylactic agent in osteomyelitis treatment. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:531,538, 2008 [source] 1H-HRMAS NMR study of smoked Atlantic salmon (Salmo salar)MAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2010David Castejón Abstract High-resolution magic angle spinning (HRMAS) NMR spectroscopic data of smoked Atlantic salmon (Salmo salar) were fully assigned by combination of one- and two-dimensional-HRMAS experiments. Complete representative spectra, obtained after few minutes of analysis time, revealed a large number of minor and major compounds in the sample. The methodology is limited by the low sensitivity of NMR, and therefore HRMAS only enables the determination of the most relevant components. These were fatty acids (FAs), carbohydrates, nucleoside derivatives, osmolytes, amino acids, dipeptides and organic acids. For the first time, spectra were resolved sufficiently to allow semiquantitative determination in intact muscle of the highly polyunsaturated FA 22:6 ,-3. Additionally, the feasibility of 1H-HRMAS NMR metabolite profiling was tested to identify some bioactive compounds during storage. This profiling was carried out by the non-destructive and direct analysis (i.e. without requiring sample preparation and multiple step procedures) of intact salmon muscle. The proposed procedure can be applied to a large number of samples with high throughput due to the short time of analysis and quick evaluation of the data. Copyright © 2010 John Wiley & Sons, Ltd. [source] Intermediates in the Autoxidation of Nitrogen MonoxideCHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2009Benedikt Galliker Abstract ONOO. is an important intermediate in the autoxidation of nitrogen monoxide by dioxygen. A formerly unknown red isomer of N2O4, ONOONO (see figure), formed in 2-methylbutane at 113,K from nitrogen monoxide and dioxygen, is converted to O2NNO2 upon warming. We have identified two intermediates in the autoxidation of NO.: ONOO., which was detected by EPR spectroscopy at 295,K and atmospheric pressure in the gas phase, and ONOONO, a red substance produced at 113,K in 2-methylbutane. The red compound is diamagnetic and absorbs maximally at 500,nm. The ONOONO intermediate is unstable above the melting point of 2-methylbutane and rapidly converts to O2NNO2. From the semiquantitative determination of mole fractions present in the gas phase by EPR spectroscopy, we estimated the rate constants for the steps that lead to ONOO. and ONOONO, from the known overall rate constant of the autoxidation reaction, by assuming that a quasi-stationary mechanism applies. The rate constant for the rate-determining formation of ONOO. is about 3.1×10,18,cm3,molecule,1,s,1 (or 80,s,1 in mole fractions), the dissociation rate constant of ONOO. is about 6.5×103,s,1, and ONOONO is formed with a rate constant of k=7.7×10,14,cm3,molecule,1,s,1 (1.9×106,s,1 in mole fractions). From these constants, we estimate that the equilibrium constant for the formation of ONOO. from NO. and O2 (K) is 4.8×10,22,cm3,molecule,1 (1.2×10,2), and, therefore, ,G=+11.0,kJ,mol,1. In water, the Gibbs energy change is close to zero. The presence of ONOO. at steady-state concentrations under dioxygen excess may be important not only for reactions in the atmosphere, but especially for reactions in aerosols and biological environments, because the rate constant for formation in solution is higher than that in the gas phase, and, therefore, the half-life of ONOO. is longer. [source] | |||||||||||||