Immobilization of enzymes on modified sio2 nanoparticles with organosilanes.

U okviru ove teze, razvijeno je nekoliko procedura za hemijsku modifikaciju površine pirogenih, neporoznih nanočestica silike (FNS) kako bi se na njihovu površinu uvele različite funkcionalne grupe. Prva procedura se sastojala od modifikacije površine nanočestica silike 3-aminopropiltrimetoksisilanom (APTMS-om) radi uvođenja primarnih amino grupa na njihovu površinu...In this thesis, different procedures for fumed nonporous silica nanoparticles (FNS) chemical modification, in terms of introducing different functional groups on the support surface, were developed..

Supplementary data for article: Banjanac, T.; Dragićević, M.; Šiler, B.; Gašić, U.; Bohanec, B.; Nestorović Živković, J.; Trifunović, S.; Mišić, D. Chemodiversity of Two Closely Related Tetraploid Centaurium Species and Their Hexaploid Hybrid: Metabolomic Search for High-Resolution Taxonomic Classifiers. Phytochemistry 2017, 140, 27–44. https://doi.org/10.1016/j.phytochem.2017.04.005

Supplementary material for: [https://doi.org/10.1016/j.phytochem.2017.04.005]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2477

Supplementary data for article: Banjanac, T.; Dragićević, M.; Šiler, B.; Gašić, U.; Bohanec, B.; Nestorović Živković, J.; Trifunović, S.; Mišić, D. Chemodiversity of Two Closely Related Tetraploid Centaurium Species and Their Hexaploid Hybrid: Metabolomic Search for High-Resolution Taxonomic Classifiers. Phytochemistry 2017, 140, 27–44. https://doi.org/10.1016/j.phytochem.2017.04.005

Supplementary material for: [https://doi.org/10.1016/j.phytochem.2017.04.005]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2477

Immobilization of enzymes on modified sio2 nanoparticles with organosilanes.

U okviru ove teze, razvijeno je nekoliko procedura za hemijsku modifikaciju površine pirogenih, neporoznih nanočestica silike (FNS) kako bi se na njihovu površinu uvele različite funkcionalne grupe. Prva procedura se sastojala od modifikacije površine nanočestica silike 3-aminopropiltrimetoksisilanom (APTMS-om) radi uvođenja primarnih amino grupa na njihovu površinu...In this thesis, different procedures for fumed nonporous silica nanoparticles (FNS) chemical modification, in terms of introducing different functional groups on the support surface, were developed..

The use of multivariate analysis of the radon variability in the underground laboratory and indoor environment

The paper presents results of multivariate analysis of variations of radon concentrations in the shallow underground laboratory and a family house, depending on meteorological variables only. All available multivariate classifi cation and regression methods, developed for data analysis in high-energy physics and implemented in the toolkit for multivariate analysis (TMVA) software package in ROOT, are used in the analysis. The result of multivariate regression analysis is a mapped functional behaviour of variations of radon concentration depending on meteorological variables only, which can be used for the evaluation of radon concentration, as well as to help with modelling of variation of radon concentration. The results of analysis of the radon concentration variations in the underground laboratory and real indoor environment, using multivariate methods, demonstrated the potential usefulness of these methods. Multivariate analysis showed that there is a potentially considerable prediction power of variations of indoor radon concentrations based on the knowledge of meteorological variables only. In addition, the online system using the resulting mapped functional behaviour for underground laboratory in the Institute of Physics Belgrade is implemented, and the resulting evaluation of radon concentrations are presented in this paper

Stabilization of immobilized lipase from Candida rugosa by amino acid treatment

Lipaze su enzimi koji imaju široku primenu u prehrambenoj, kozmetičkoj i farmaceutskoj industriji. U industrijskoj praksi primenjuju se imobilisane lipaze, s obzirom da se imobilizacijom povećava stabilnost samog enzima, ali i ekonomičnost enzimskog postupaka proizvodnje. Kao nosači za imobilizaciju najčešće se koriste sintetski ili prirodni polimeri bogati funkcionalnim grupama preko kojih se enzim može vezati. U nekim slučajevima, neophodna je prethodna modifikacija nosača radi uvođenja funkcionalnih grupa. U ovom radu lipaza je imobilisana na modifikovanu jonoizmenjivačku smolu, Purolite® A109, koja je u osnovi kopolimer stirena i divinilbenzena, a koja na površini poseduje primarnu amino grupu. Modifikacija nosača izvršena je sa ciljem da se primarne amino grupe nosača prevedu u epoksi grupe, čime se dobija nosač pogodan za kovalentnu imobilizaciju lipaze. Kovalentna imobilizacija je do sada pokazala najbolje rezultate kada su u pitanju aktivnost i stabilnost dobijenih imobilizata1,2. Dobijeni imobilizati tretirani su aminokiselinama da bi se ispitalo njihovo dejstvo na stabilnost i aktivnost imobilisane lipaze. Efekat tretmana aminokiselinama na stabilnost imobilisane lipaze praćen je ispitivanjem aktivnosti netretiranog i tretiranih imobilizata tokom inkubacije na 65 °C.Lipases are important catalysts in pharmaceutical, cosmetics and food industry. On industrial scale, lipases are used only in immobilized form. Majority of enzymes lose part of its initial activity during immobilization process, but activity also decreases throughout storage and usage of immobilized lipase. Therefore, adequate immobilization supports are prerequisite for successful application of immobilized enzyme. When it comes to epoxy supports, after immobilization unreacted epoxy groups can interact with side chains of protein, which could result in additional enzyme activity loss. Blocking of epoxy groups is usually performed with 2- mercaptoethanol or ethylenediamine. In this study, treatment of immobilized lipase with different amino acids (glycine, phenylalanine, arginine and aspartic acid) was performed. Phenylalanine and glycine exhibited positive effect on stabilization of immobilized lipase, so this treatment should be examined more thoroughly. On the other hand, arginine and aspartic acid showed no effect on stabilization of immobilized lipase

Modified nanocellulose as a support for adsorption of lipase from Candida rugosa

Sa ubrzanim razvojem nanotehnologije, celuloza kao najrasprostranjeniji i najvažniji prirodni polimer na zemiji privlači sve veću pažnju u formi nanoceluloze. Zbog svoje biodegradabilnosti, biokompatibilnosti i velike specifične površine nanoceluloza je veoma pogodan material za imobilizaciju enzima. U cilju ostvarivanja stabilnije veze između nosača i enzima i dobijanja biokatalizatora sa što većom katalitičkom aktivnosti, u ovom radu su različitim metodima funkcionalizacije na površinu nanoceluloze uvedene amino i karboksilne grupe. Određen je broj uvedenih grupa, svi materijali okarakterisani su FT-IR spektroskopijom i TG analizom, a određen je i zeta potencijal površina. Ispitan je uticaj jonske jačine rastvora i adsorpcija lipaze iz Candida rugosa testirana je u 0,1 i 1 M fosfatnom puferu, a rezultati ispitivanja aktivnosti pokazali su da je enzim nakon imobilizacije zadržao čak 54,5 % od početne aktivnosti.With the rapid development of nanotechnology, cellulose as the most abundant and important natural polymer on earth, is attracting increasing attention in its form of nanocellulose. Due to its biodegradability, biocompatibility and large specific surface nanocellulose is a very suitable material for the immobilization of enzymes. In order to accomplish more stable bond with the enzyme and obtain biocatalyst with high catalytic activity, in this paper nanocellulose surface was functionalized with different methods, and amino and carboxyl groups were introduced. All materials were characterized by FT-IR spectroscopy and TG analysis, and in addition, zeta potential of all surfaces was determined. The effect of the ionic strength of the solution on the adsorption of the lipase from Candida rugosa was tested in 0.1 and 1 M phosphate buffer, and the activity results showed that after immobilization lipase retained 54.5% of the initial activity

Activation of antioxidant response element in mouse primary cortical cultures with sesquiterpene lactones isolated from Tanacetum parthenium

Tanacetum parthenium produces biologically active sesquiterpene lactones (SL). Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor known to activate a series of genes termed the antioxidant response element (ARE). Activation of Nrf2/ARE may be useful for the treatment of neurodegenerative disease. In this study we isolated 11 SL from T. parthenium with centrifugal partition chromatography and semipreparative HPLC. Compounds were screened in vitro for their ability to activate the ARE on primary mouse cortical cultures as well as for their toxicity towards the cultures. All SL containing the a-methylene-¿-lactone moiety were able to activate the ARE and cause cellular toxicity. The structure-activity relationship among the SL isolated indicates that the guaianolides were more active and when lacking the endoperoxide functionality less toxic then the germacranolides

Secoiridoid glycosides as a marker system in chemical variability estimation and chemotype assignment of Centaurium erythraea Rafn from the Balkan Peninsula

The content of secoiridoid glycosides in the aerial parts and roots of in vitro grown centaury (Centaurium etythraea Rafn) plants, originating from 52 Balkan Peninsula populations was analyzed. The results of this study give insight into the infraspecific variability of centaury, based on the yield of secoiridoid glycosides as chemical markers of phenotypic variation. According to the cluster analysis, existence of two basic chemotypes is suggested. Moreover, the impact of prevailing environmental gradients in natural habitats on chemotype differentiation was assessed. The precipitation rate of the warmest quarter of year significantly affects the accumulation of secondary metabolites. These results will enable the selection of particular populations which are characterized by enhanced accumulation of secondary metabolites of interest, thus making it possible to realize the commercial field cultivation and upscale production and of this threatened and pharmacologically important species. (C) 2012 Elsevier B.V. All rights reserved.Ministry of Education and Science of Serbia [173024, 173025

Antibacterial and Antifungal Screening of Centaurium pulchellum Crude Extracts and Main Secoiridoid Compounds

The main principles of C. pulchellum (Sw.) Druce, secoiridoid glycosides, have been studied as potent bioactive compounds. Here we scored their content in extracts of ten populations of this species. Antibacterial and antifungal assays of the extracts and pure secoiridoid glycosides were performed against eight bacterial strains and five fungal species. Methanol extracts from both aerial parts and roots exhibited excellent antibacterial (0.05-0.2 mg mL(-1)) and very good antifungal (0.1-2 mg mL(-1)) activity. Pure secoiridoid glycosides isolated from these extracts demonstrated very strong antibacterial (0.01-0.04 mg mL(-1)) and especially antifungal (0.001-0.1 mg mL(-1)) activity.Serbian Ministry of Science and Technological Development [143031, 143041