15 research outputs found
Carbohydrate Composition of Endotoxins from R-type Isogenic Mutants of Shigella sonnei Studied by Capillary Electrophoresis and GC-MS
S3 Code. Matlab code to simulate epidemic when hosts perform a Levy wal
Carbohydrate Composition of Endotoxins from R-type Isogenic Mutants of Shigella sonnei Studied by Capillary Electrophoresis and GC-MS
The carbohydrate composition of the rough-type endotoxins (lipopolysaccharides, LPSs) from
Shigella sonnei mutant strains (Shigella sonnei phase II - 4303, 562H, R41 and 4350) was investigated by
capillary electrophoresis and GC-MS. The monosaccharides obtained by hydrolysis were determined by
capillary electrophoresis combined with laser induced fluorescence detection (CE-LIF) after labeling with
8-aminopyrene-1,3,6-trisulfonic acid (APTS) and by GC-MS as alditol-acetate derivatives. It was obtained
that the lipopolysaccharides of the isogenic rough mutants are formed in a step-like manner, containing
no heptose (4350), one D-glycero-D-mannoheptose (562H), or two or three L-glycero-Dmannoheptoses
(R41, 4303, respectively) in the deep core region. Besides the heptoses, the longest
LPS from the mutant Shigella sonnei 4303 contains hexoses, such as glucoses and galactoses, in a proportion
of approximately 3:2. This study provides a comprehensive comparison of the variability in
the carbohydrate part of the rough endotoxins extracted from Shigella sonnei isogenic mutants.
(doi: 10.5562/cca1795
Lipid A foszforilációs- és acilációs izomereinek elválasztása és jellemzése NACE-ESI-MS/MS módszerrel: Separation and characterization of the phosphorylation and acylation isomers of lipid A by NACE-ESI-MS/MS
Lipid A is the anchor of endotoxins on the surface of Gram-negative bacteria. In the human body, it is a prominent stimulator of the immune system, but it may also cause dangerous medical conditions, such as endotoxic shock and sepsis. To reveal the specific structural parts and molecular heterogeneity of lipid A isolates, such as the site of phosphorylation and type of fatty acyl chains, a pressure-assisted non-aqueous capillary electrophoresis – tandem mass spectrometry method was developed. Baseline separation of both phosphorylation and acylation isomers was achieved. Identification was carried out from the tandem mass spectra recorded in the positive ionization mode. B-type ions are formed by diagnostic neutral losses. B2 type ions are confirming the site of phosphorylation, while B1 type ions and other fragments are enabling the characterization of acylation isomers. This novel method should be regarded as an orthogonal technique to formerly developed LC‐MS/MS methods in the screening of bacterial samples or lipid A based therapeutics.
Kivonat
Az endotoxinok a lipid A részükkel ágyazódnak be a Gram-negatív baktériumok sejtmembránjába. Az emberi szervezetben a lipid A hatékonyan stimulálja az immunrendszert, de akár súlyos egészségi állapotokat is előidézhet, mint az endotoxikus sokk, vagy a szepszis. A szerkezetének részleteinek megismerésére és a lipid A izolátum alkotóinak változatosságát – úgymint a foszforilációs helyek és a kapcsolódó zsírsavláncok típusát – feltárandó kifejlesztettünk egy nyomással segített nemvizes kapilláris elektroforézis–tandem tömegspektrometriás módszert. A foszforilációs- és az acilációs izomereknél is sikeres alapvonali elválasztást értünk el. A szerkezeti információt a pozitív ion módban felvett tandem tömegspektrumok szolgáltatták. Diagnosztikus semleges vesztésekkel B-típusú ionok keletkeznek. A B2-típusú ionok azonosítják a foszforilációs pozíciót, míg a B1 ionok az acilációs izomerek jellemzését teszik lehetővé. Jelen módszer a korábban kifejlesztett LC-MS/MS módszerek kiegészítője lehet a bakteriális eredetű minták vizsgálatában és a lipid A klinikai alkalmazásakor
Bioadsorption characteristics of Pseudomonas aeruginosa PAOI
Biosorption of Cd(II) and Pb(II) ions from aqueous solution using lyophilized
Pseudomonas aeruginosa (PAOI) cells were observed under various experimental
conditions. The effect of pH, initial metal concentration, equilibration time
and temperature on bioadsorption was investigated. The optimum pH value for
Pb(II) adsorption was found to be 5.0, and for Cd(II) 5.0 − 6.0. The Pb(II)
and Cd(II) bioadsorption equilibrium were analyzed by using Freundlich and
Langmuir model using nonlinear least-squares estimation. The experimental
maximum uptake capacity of Pb(II) and Cd(II) was estimated to be 164 mg g-1
and 113 mg g-1, respectively. For biosorption kinetic study the pseudo
second-order kinetic model was applied at various temperatures. The
temperature had no significant effect on Pb(II) bioadsorption. In case of
Cd(II) bioadsorption the adsorbed amount decreased with increasing
temperature
Bioanalitikai kérdések: Bioanalytical solutions
Fatty acids everywhere, ionic liquids and proteins, endotoxin structure and function.
Kivonat
Zsírsavak mindenhol, ionfolyadékok és fehérjék, endotoxin szerkezet és funkció.
 
The myth of data acquisition rate
Abstract With the need for high-frequency data acquisition, the influence of the data acquisition rate on the quality of the digitized signal is often discussed and also misinterpreted. In this study we show that undersampling of the signal, i.e. low data acquisition rate will not cause band broadening. Users of modern instrumentation and authors are frequently misled by hidden features of the data handling software they use. Very often users are unaware of the noise filtering algorithms that run parallel with data acquisition and that lack of information misleads them. We also demonstrate that undersampled signals can be restored by a proper trigonometric interpolation