Nyomelem speciáció oldószer mentes mikroextrakciós módszerekkel = Application of solvent free microextraction methods for trace element speciation

Az összes krómtartalom meghatározására tengervízből izotóp hígításos nagyfelbontású induktiv csatolású plazma-ionizációs tömegspektrometriás módszert dolgoztunk ki, melynél a mintabevitelt GC elválasztás után közvetlenül oldottuk meg TFAs derivatizációval. A módszert továbbfejlesztve összevetettük a hatásfokokat ECD EI-MS és ICP-Ms detektálásnál.Megállapítottuk, hogy A metilhigany és etilhigany vegyületek eltérően viselkednek mikrohullámú besugárzás hatására, mely nagy mértékben befolyásolhatja a speciációs meghatározásukat. Lúgos feltárás és fenilezési rekció kidolgozásával SPME-GC-AFS módszert dolgoztunk ki halminták higanyspecieszeinek meghatározására. | For the determination of total chromium concentration in seawater an isotope dilution sector field inductively coupled plasma mass spectrometry method was developed, wher for the sample introduction a GC method after TFA derivatization was used. The efficiency of the method was compared using ECD, EI-MS and ICP-MS detection. The degradation behaviour of methylmercury and ethylmercury under microwave irradiation was invesigated, where the effect of irradiation will change the detectability of species. An SPME-GC-AFS determination of methyladet mercury compunds was developed after alkaline sample degradation and phenylation derivatization

Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal in Membrane Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

Hipoalergeni antibakterijski peptidi male molekularne mase proizvedeni su iz nemasne sojine sačme u membranskom bioreaktoru. U prvom su koraku proteini sojine sačme razgrađeni pomoću tripsina u šaržnom bioreaktoru. Optimalni uvjeti za razgradnju tripsinom bili su: koncentracija sojine sačme od 75 g/L, temperatura od 40 °C i pH=9. Nakon toga su peptidi male molekularne mase pročišćeni pomoću „cross-flow“ membrane (veličina pora 100 μm), a zatim pomoću keramičke cjevaste membrane (veličine pora koja ne propušta molekule veće od 5 kDa). Ispitan je utjecaj transmembranskog pritiska i primjene statičkih promotera turbulencije na smanjenje koncentracijske polarizacije blizu površine ultrafiltracijske membrane, te je potvrđen njihov pozitivan učinak. Transmembranski pritisak od 3•105 Pa i diskontinuirana dijafiltracija provedena u tri koraka bili su optimalni za filtraciju pomoću ultrafiltracijske membrane. Distribucija molekularne mase peptida pročišćenih pomoću ultrafiltracijske membrane utvrđena je pomoću metode LC-ESI-Q-TOF-MS. Više od 96 % peptida (izraženih kao relativna frekvencija) iz permeata ultrafiltracijske membrane imalo je molekularnu masu manju od 1,7 kDa, a najveća je molekularna masa bila 3,1 kDa. Smanjenje alergenih svojstava proteina za više od 99,9 % nakon obrade tripsinom i membranske filtracije utvrđeno je imunoenzimskim testom. Također je zaključeno da peptidi pročišćeni pomoću ultrafiltracijske membrane pozitivno djeluju na rast bakterije Pediococcus acidilactici HA6111-2, te sprečavaju rast bakterije Bacillus cereus.Hypoallergenic antibacterial low-molecular-mass peptides were produced from defatted soybean meal in a membrane bioreactor. In the first step, soybean meal proteins were digested with trypsin in the bioreactor, operated in batch mode. For the tryptic digestion of soybean meal protein, optimum initial soybean meal concentration of 75 g/L, temperature of 40 °C and pH=9.0 were determined. After enzymatic digestion, low-molecular-mass peptides were purified with cross-flow flat sheet membrane (pore size 100 μm) and then with tubular ceramic ultrafiltration membrane (molecular mass cut-off 5 kDa). Effects of transmembrane pressure and the use of a static turbulence promoter to reduce the concentration polarization near the ultrafiltration membrane surface were examined and their positive effects were proven. For the filtration with ultrafiltration membrane, transmembrane pressure of 3·10^5 Pa with 3-stage discontinuous diafiltration was found optimal. The molecular mass distribution of purified peptides using ultrafiltration membrane was determined by a liquid chromatography–electrospray ionization quadrupole time-of-flight mass spectrometry setup. More than 96 % of the peptides (calculated as relative frequency) from the ultrafiltration membrane permeate had the molecular mass M≤1.7 kDa and the highest molecular mass was found to be 3.1 kDa. The decrease of allergenic property due to the tryptic digestion and membrane filtration was determined by an enzyme-linked immunosorbent assay and it was found to exceed 99.9 %. It was also found that the peptides purifi d in the ultrafi tration membrane promoted the growth of Pediococcus acidilactici HA6111-2 and they possessed antibacterial activity against Bacillus cereus

Selenium tolerance, accumulation, localization and speciation in a Cardamine hyperaccumulator and a non-hyperaccumulator

Cardamine violifolia (family Brassicaceae) is the first discovered selenium hyperaccumulator from the genus Cardamine with unique properties in terms of selenium accumulation, i.e., high abundance of selenolanthionine. In our study, a fully comprehensive experiment was conducted with the comparison of a non-hyperaccumulator Cardamine species, Cardamine pratensis, covering growth characteristics, chlorophyll fluorescence, spatial selenium/sulfur distribution patterns through elemental analyses (synchrotron-based X-Ray Fluorescence and ICP-OES) and speciation data through selenium K-edge micro X-ray absorption near-edge structure analysis (μXANES) and strong cation exchange (SCX)-ICP-MS. The results revealed remarkable differences in contrast to other selenium hyperaccumulators as neither Cardamine species showed evidence of growth stimulation by selenium. Also, selenite uptake was not inhibited by phosphate for either of the Cardamine species. Sulfate inhibited selenate uptake, but the two Cardamine species did not show any difference in this respect. However, μXRF derived speciation maps and selenium/sulfur uptake characteristics provided results that are similar to other formerly reported hyperaccumulator and non-hyperaccumulator Brassicaceae species. μXANES showed organic selenium, "C-Se-C", in seedlings of both species and also in mature C. violifolia plants. In contrast, selenate-supplied mature C. pratensis contained approximately half "C-Se-C" and half selenate. SCX-ICP-MS data showed evidence of the lack of selenocystine in any of the Cardamine plant extracts. Thus, C. violifolia shows clear selenium-related physiological and biochemical differences compared to C. pratensis and other selenium hyperaccumulators

Microstructuration of poly(3-hexylthiophene) leads to bifunctional superhydrophobic and photoreactive surfaces

Schematic representation and a preparation route for the poly(3-hexylthiophene) conducting polymer film having both superhydrophobic and visible-light active photocatalytic properties.</p

IL-36α and Lipopolysaccharide Cooperatively Induce Autophagy by Triggering Pro-Autophagic Biased Signaling

Autophagy is an intracellular catabolic process that controls infections both directly and indirectly via its multifaceted effects on the innate and adaptive immune responses. It has been reported that LPS stimulates this cellular process, whereas the effect of IL-36α on autophagy remains largely unknown. We therefore investigated how IL-36α modulates the endogenous and LPS-induced autophagy in THP-1 cells. The levels of LC3B-II and autophagic flux were determined by Western blotting. The intracellular localization of LC3B was measured by immunofluorescence assay. The activation levels of signaling pathways implicated in autophagy regulation were evaluated by using a phosphokinase array. Our results showed that combined IL-36α and LPS treatment cooperatively increased the levels of LC3B-II and Beclin-1, stimulated the autophagic flux, facilitated intracellular redistribution of LC3B, and increased the average number of autophagosomes per cell. The IL36α/LPS combined treatment increased phosphorylation of STAT5a/b, had minimal effect on the Akt/PRAS40/mTOR pathway, and reduced the levels of phospho-Yes, phospho-FAK, and phospho-WNK1. Thus, this cytokine/PAMP combination triggers pro-autophagic biased signaling by several mechanisms and thus cooperatively stimulates the autophagic cascade. An increased autophagic activity of innate immune cells simultaneously exposed to IL-36α and LPS may play an important role in the pathogenesis of Gram-negative bacterial infections