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. &nbsp

Study of the phenolic profile of Vranec and Merlot wines produced under different vinification conditions

Polyphenols are large family of naturally occurring, structurally diverse, organic compounds abundant in plants. Phenolic compounds such as anthocyanins, flavonols and tannins are important constituents of red wine contributing to the taste, color, mouthfeel and quality. They are also associated with the health-promoting properties of red wine. The proportion of the different polyphenols in wine vary according to the type of grape,maturity and the type of vinification. In this study, phenolic profile of Vitis Vinifera red wines Vranec and Merlot (vintage 2021), produced in Republic of N. Macedonia, has been evaluated. Wines have been produced with three winemaking techniques, including classical fermentation, roto process and punchdown method in order to study and compare the effect of vinification on the individual phenolic compounds. The phenolic profile was determined using an UPLC technique coupled with DAD and MS detectors. ESI-IT-MS method with alternating ionization polarity was used for identification of the phenolic compounds [1]. In total, 50 phenolic components were identified, divided into the following groups: phenolic acids and derivates, stilbens, flavonols, dihydroflavonols, flavan-3-ols and antocyanins. Individual standard solutions of 9 phenolic compounds (gallic acid, caffeic acid, 4-coumaric acid, ferulic acid, 2,4-dihidroxibenzoic acid, syringic acid, rutin, quercetin, and cis-resveratrol ) were prepared and used for construction of calibration curves as well as for quantification of the individual phenolics. Considering the influence of winemaking method, it was observed that wines from both varieties produced with roto process had highest content of phenolic compounds. Compared to the classical fermentation, the content of phenolic compounds was about 30% higher in the wines obtained by the roto method

Determination of polyphenolic profile of Pinot Noir wines with UPLC-ESI-IT-MS technique

Polyphenols are large and complex group of compounds that determine the quality of wines and influence the colour, mouthfeel, astringency and bitterness. They are divided into two main groups: flavonoids and nonflavonoids. In this study, the focus of research was set on determination of polyphenolic profile of red wines from Pinot Noir variety (Vitis Vinifer L.) (vintage 2021), produced in Imako winery, Štip, R.N. Macedonia. UPLC-ESI-IT-MS technique was used for identification and quantification of different groups of phenolic compounds, based on the mass spectra of individual compounds compared to the spectra from the literature. In total, 50 phenolic components have been identified, divided into the following groups: phenolic acids and derivates, stilbens, flavonols, dihydroflavonols, flavan-3-ols and antocyanins. Gallic acid was detected producing the deprotonated ions in negative ion mode at 169 and 153, forming fragments at m/z 125 and 109, respectively as a result of loss of CO2 from the carboxylate group. The presence of anthocyanins (glucosides, acetylglucosides and p-coumaroylglucoside derivatives of delphinidin, cyanidin, petunidin, peonidin and malvidin), the main pigments in red wines and responsible for the colour, was confirmed. All of them presented a similar fragmentation pattern containing two signals, the orginal M+ molecular ion, and the fragments [M-162]+, [M-204]+ and [M-308]+ which are result of elimination of glucose, acetylglucose and p-coumaroylglucose residues, respectively. The flavan-3-ol monomers, (+)-catechin and (-)-epicatechin were detected at m/z 289. (-)-Flavan-3-ol dimers with molecular ion at m/z 577 were identified as procyanidins B1, B2, B3 and B4. Differences between vinification techniques were noticed confirming that maceration time influence the phenolic content in wine

Phenolic profile of Merlot wines detrmined by UPLC-ESI-IT-MS

In this study, the phenolic profile of Merlot wines (Vitis Vinifera L.) produced with classical fermentation, roto process and punchdown method (harvest 2021) has been determined using an UPLC technique coupled with DAD and ESI-IT-MS. Identification was performed by ESI-IT-MS method with alternating ionization polarity [1]. Analyses were performed on a CORTEX UPLC C18 column (1.6 μm x 2.1 x 150 mm) with gradient elution using a binary mobile phase consisting of 1% (v/v) acetic acid in water as solvent A and 1% (v/v) acetic acid in methanol as solvent B. For the elution programme, the following proportion of solvent B was used: 0-10 min 5-20% B, 10-45 min 20-50% B, 45-50 min 50- 80% B, 50-60 min 80-90% B. The injection volume was 2µL. Identification of the compounds was based on retention time, UV-Vis and mass spectra compared with the available standards and data from the literature. In total, 50 phenolic components were identified, divided into the following groups: phenolic acids and derivates, stilbens, flavonols, dihydroflavonols, flavan-3-ols and antocyanins. UPLC-MS extracted ion chromatograms were calculated by summing up the intensities of the specified masses in the mass spectra. Ion intensities were extracted at the m/z values of the molecular (M+ ) or the quasi-molecular ([M+H]+ , [M-H]- ) ions of the detected compounds. From the group of hydroxybenzoic acids, gallic acid was detected producing the deprotonated ion in negative ion mode at 169 and 153, respectively, forming fragments at m/z 125 and 109 as a result of loss of CO2 from the carboxylate group. From the group of anthocyanins, the presence of glucoside, acetylglucoside and p-coumaroylglucoside derivatives of delphinidin, cyanidin, petunidin, peonidin and malvidin were confirmed in the Merlot wines. All of them had similar fragmentation pattern containing two signals, the original M+ molecular ion, and the fragments [M-162]+ , [M-204]+ and [M-308]+ which are result of elimination of glucose, acetylglucose and p-coumaroylglucose residues, respectively. Considering the influence of winemaking method, it was observed that wine produced with roto process presented highest content of phenolic compounds. Compared to the classical fermentation, the content of phenolic compounds was about 30% higher in the wine obtained by the roto method