Fina strukturna analiza fungalnog polisaharida pululana dobijenog pomoću Aureobasidium pullulans, soj CH-1

The structure of pullulan, the extracellular α-D-glucan elaborated by the yeast-like fungus Aureobasidium pullulans, may be described as a linear α-D-glucan consisting of maltotriosyl repeat units connected terminally by (1->6)-α-D-glucosidic bonds. Occasionally some of maltotriosyl residues are replaced by higher oligosaccharide units, most frequently with maltotetraosyl residues. Using the susceptibility of pullulan CH-1 (obtained from strain CH-1 of Aureobasidium pullulans) to hydrolysis catalysed by porcine alpha-amylase, the polysaccharide was cleaved and the fragments obtained fractionated by gel-permeation chromatography. The heterogenous size of the fragments indicates that there is no apparent regular distribution of tetrasaccharide units in the pullulan chain. Enzymatic digestion of pullulan CH-1 using pullulanase, followed by gel-permeation chromatography of the resulting digest confirmed these results as did preparative paper chromatography and CI mass spectrometry of the separated components, i.e., that maltotetraosyl units (about 7 %) are building units of pullulan CH-1.Pululan, ekstracelularni polisaharid koji proizvodi kvascu slična gljiva Aureobasidium pullulans, jeste linearni glukan čiju strukturu pretežno čine polimaltotriozil ostatci povezani međusobno α-(1->6)-glikozidnim vezama. Varijacije u strukturi ovog polisaharida mogu nastati usled zamene maltotrioznih ostataka na pojedinim mestima polimernog lanca oligosaharidnim fragmentima dužeg niza, najčešće maltotetraoznim ostacima. U ovom radu ispitan je pululan koji proizvodi A. pullulans, soj CH-1, enzimskom hidrolizom sa pankreasnom α-amilazom i pululanazom, sa ciljem da se utvrdi da li i u kom odnosu ovaj polisaharid sadrži oligosaharidne fragmente, kao i da se odredi dužina oligosaharidnog niza, odnosno broj monosaharidnih ostataka koji ulaze u njegov sastav. Primenom uobičajenih analitičkih metoda (gel-filtraciona hromatografija, metilaciona analiza, preparativna hromatografija kombinovana sa masenom spektrometrijom metilovanih oligosaharidnih alditola), utvrđeno je da su maltotetraozne jedinice (oko 7 %) integralni deo polisaharidnog lanca pululana CH-1. Raspored ovih jedinica je nasumičan

(1->3)- β-D-glukan iz saccharomyces cerevisiae - dobijanje, karakterizacija i hemijska modifikacija uvođenjem karbonilnih grupa u polisaharidni niz

A number of polysaccharides with [3-glycosidic linkage are widespread in a variety of sources. All have a common structure, the (1->3)- β -D-glucan backbone is essential. They have attracted attention because of bioactive and medicinal properties which have been described for more than 50 years. Glucan from technologically important species, baker's yeast Saccharomyces cerevisiae. was isolated in a purified form and characterized. Data from common analytical methods supported by GLC-MS and NMR spectra indicated that isolated glucan from Saccharomyces cerevisiae has a backbone chain up of (l->3)- β -D-linked glucopyranoses with single β -D-glucopyranosul units at the branch points on every eight main chain unit. The oxidative transformation of β -D-glucan was investigated with dimethyl sulfoxide-acetic-anhydride reagent. Keto-aldehydo polymers were generated by treatment of β -D-glucan with this reagent. Accompanyng'the oxidation was the formation of (methylthio)methyl groups along the polysaccharide chain at a degree of substitution smaller than the degree of substitution for the carbonyl group. As these groups groups are acid-labile, it has been found that can be removed by acid hydrolysis under conditions that not affect on the carbonyl content.Brojni polisaharidi sa p-glikozidnom vezom rasprostranjeni su u različitim izvorima. Svi imaju opštu strukturu u kojoj je (l->3)- β -D-glukan suštinska gradivna jedinica. Oni privlače pažnju zato što su bioaktivni i imaju medicinske osobine, koje su bile opisane pre više od 50 godina. Cinkanje izolovan u čistom obliku i okarakterisan iz pekarskog kvasca Sacclwromyces cerevisiae kao tehnološki važnog proizvoda. Podaci dobijeni pomoću opštih analitičkih metoda i potvrdjeni GLC-MS i NMR spektrima, ukazuju da izolovani glukan iz Saccharomyces cerevisiae ima kao osnovni gradivni niz (l->3)- β -D-povezane glukopiranoze sa pojedinačnim β -D-glukopiranoznim jedinicama u tačkama račvanja na svakih osam jedinica glavnog lanca. Oksidativna transformacija β -D-glukana ispitivana je sa reagensom dimetil sulfoksid-anhidrid sirćetne kiseline, pri čemu su dobijeni keto-aldehido polimeri. Oksidaciju prati nastajanje (metiltio)metil grupa duž polisaharidnog niza, a stepen supstitucije je manji nego za karbonilnu grupu. Pošto su ove grupe acido-labilne, utvrdjeno je da mogu da se eliminišu kiselom hidrolizom, bez uticaja na sadržaj karbonila

(1->3)- β-D-glukan iz saccharomyces cerevisiae - dobijanje, karakterizacija i hemijska modifikacija uvođenjem karbonilnih grupa u polisaharidni niz

A number of polysaccharides with [3-glycosidic linkage are widespread in a variety of sources. All have a common structure, the (1->3)- β -D-glucan backbone is essential. They have attracted attention because of bioactive and medicinal properties which have been described for more than 50 years. Glucan from technologically important species, baker's yeast Saccharomyces cerevisiae. was isolated in a purified form and characterized. Data from common analytical methods supported by GLC-MS and NMR spectra indicated that isolated glucan from Saccharomyces cerevisiae has a backbone chain up of (l->3)- β -D-linked glucopyranoses with single β -D-glucopyranosul units at the branch points on every eight main chain unit. The oxidative transformation of β -D-glucan was investigated with dimethyl sulfoxide-acetic-anhydride reagent. Keto-aldehydo polymers were generated by treatment of β -D-glucan with this reagent. Accompanyng'the oxidation was the formation of (methylthio)methyl groups along the polysaccharide chain at a degree of substitution smaller than the degree of substitution for the carbonyl group. As these groups groups are acid-labile, it has been found that can be removed by acid hydrolysis under conditions that not affect on the carbonyl content.Brojni polisaharidi sa p-glikozidnom vezom rasprostranjeni su u različitim izvorima. Svi imaju opštu strukturu u kojoj je (l->3)- β -D-glukan suštinska gradivna jedinica. Oni privlače pažnju zato što su bioaktivni i imaju medicinske osobine, koje su bile opisane pre više od 50 godina. Cinkanje izolovan u čistom obliku i okarakterisan iz pekarskog kvasca Sacclwromyces cerevisiae kao tehnološki važnog proizvoda. Podaci dobijeni pomoću opštih analitičkih metoda i potvrdjeni GLC-MS i NMR spektrima, ukazuju da izolovani glukan iz Saccharomyces cerevisiae ima kao osnovni gradivni niz (l->3)- β -D-povezane glukopiranoze sa pojedinačnim β -D-glukopiranoznim jedinicama u tačkama račvanja na svakih osam jedinica glavnog lanca. Oksidativna transformacija β -D-glukana ispitivana je sa reagensom dimetil sulfoksid-anhidrid sirćetne kiseline, pri čemu su dobijeni keto-aldehido polimeri. Oksidaciju prati nastajanje (metiltio)metil grupa duž polisaharidnog niza, a stepen supstitucije je manji nego za karbonilnu grupu. Pošto su ove grupe acido-labilne, utvrdjeno je da mogu da se eliminišu kiselom hidrolizom, bez uticaja na sadržaj karbonila

The concentrations of heavy metals in the liver and muscle tissue of three kinds of fish during five year period

Fish, as the top of the trophic pyramid of aquatic ecosystems, are one of the most sensitive bioindicators for the presence of heavy metals in the aquatic ecosystems that inhabit them. Concentrations of cadmium (Cd), lead (Pb), mercury (Hg) and zinc (Zn) were determined in the muscle tissue and liver of selected fish species from the Zapadna Morava River during 2013 and 2018, respectively. The aim of this paper was to obtain a more complete insight into the level of accumulation of heavy metals in the organism of fish, especially fish meat as an edible part that should satisfy the health safety for human consumption. Investigations of the concentration of the presence of heavy metals from Carassius auratus, Abramis brama and Squalius cephalus have revealed various bioaccumulation of heavy metals. Among the examined fish, the highest accumulation of heavy metals was found in Abramis brama, Carassius auratus and Squalius cephalus, respectively. In all fish for all four investigated heavy metals, higher concentrations were detected in the liver and less in fish muscle. Bioaccumulation of heavy metals had the following trend: Zn > Pb > Cd > Hg.The determined concentrations of the analyzed heavy metals in fish muscle were not within the permitted limits of the MAC national legislation of the Republic of Serbia. Meat of investigated fish species is not health-safe and hygienically correct for use in human nutrition (The Official Gazette Republic of Serbia No 22/2018 and No 90/2018). The content of tested heavy metals in fish meat indicates that in this aquatic ecosystem during the five year period there was no significant pollution with these heavy metals

Utjecaj strukturalnoga istraživački usmjerenoga pristupa učenju na dostignuća budućih učitelja

The study examines the impact of structural inquiry-based learning (IBL) approach on future teacher performance – their test achievements and perceived mental effort invested in completing tests. The study included 38 students at the Faculty of Education in Belgrade who were trained how to create instruments for assessing physical quantities, such as thermometer and barometer, while attending the course Geographical concepts through experiments. Focusing on interdisciplinarity, the course tasks encouraged participants to think about new problem situations and detect causal relations among physical phenomena. The results show that the IBL approach has led to higher achievement and lower values of perceived mental effort. The decrease in mental effort points to the possibility of handling larger amounts of information in working memory and processing them in long-term memory. Due to complex relationship between the variables, the model of neural networks has shown that mental effort and the cognitive complexity of the item significantly affect on the participants’ achievement. The results are useful to in-service teachers as they point to the effectiveness and the guidelines for the implementation of the IBL approach.Istraživanje proučava utjecaj strukturalnoga istraživački usmjerenoga pristupa učenju (IBL) na dostignuća budućih učitelja – njihova postignuća i percepciju mentalnoga napora uloženoga u rješavanje testova. Istraživanje je uključivalo 38 studenata Učiteljskog fakulteta u Beogradu koji su tijekom sudjelovanja u kolegiju Geografski pojmovi kroz eksperimente postali osposobljeni za kreiranje instrumenata za provjeru fizičkih veličina poput termometra i barometra. Usmjeren na interdisciplinarnost, kolegij je potaknuo sudionike na promišljanje o novim problemskim situacijama i na otkrivanje uzročnih veza među fizičkim pojavama. Rezultati pokazuju da istraživački usmjeren pristup dovodi do većega postignuća i smanjenih vrijednosti percepcije mentalnoga napora. Smanjenje mentalnoga napora ukazuje na mogućnost obrade veće količine informacija u radnoj memoriji i procesiranje u dugoročnom pamćenju. Zbog složenih veza među varijablama, model neuronskih mreža pokazao je da mentalni napor i kognitivna složenost čestice značajno utječu na postignuća sudionika. Rezultati su korisni za buduće učitelje jer ukazuju na učinkovitost IBL pristupa i daju smjernice za primjenu istoga

Poređenje biosorpcije sa Aureobasidium pullulans soj CH-1 i polimer sorpcije na Poli(GMA-co-EGMA)teških metala iz otpadnih voda

The intact microbial cells as well as derived microbial products can be highly efficient bioacummulators of both soluble and participate forms of metals, especially from dilute external concentrations (1,2). The reason for testing Aureobasidium pullulans as a biosorbent is the fact that this fungus presents a ubiquitous saprophite that occurs commonly in the phytoshere (3). Therefore, it has enabled the use of carbohydrate wastes as substrates for the production of pullulan such as the peat hydrolysate. The metal removal and recovery processes include: precipitation, adsorption and biosorption, electrowinning and electocoagulation, cementation, membrane separation, solvent extraction and ion exchange (4). Galvanic waste effluent contain heavy metals ions, such as Cu2f, Cr1+, Cr6+, Cd2+, Ni2+, etc., which present environmental hazard. Having all this in mind, the aim of this paper is to examine the possibility of applying Aureobasidium pullulam CH-1 (Collection of Microorganisms, IChTM) as a biosorbent of metals and biosynthesis of pullulan at the same time on peat hydrolisate, distribution of sorbed metals between biomass and pullulan, as well as the correlation between biosorption Aureobasidium pullulam CH-1 and polymer sorption on poly(GMA-co-EGDMA)-en of heavy metals from galvanic waste effluent.Ispitivanje Aureobasidium pullulans, soj CH-1 kao biosorbenta je urađeno na kiselom hidrolizatu treseta sa lokaliteta Vlasinskog jezera. Kiseli hidrolizat treseta je dobijen na isti način kao i otpadne vode pri industrijskoj obradi treseta. Rezultati su pokazali da Aureohusidium pullulans, soj CH-1 može istovremeno da vrši biosorpciju metala i biosintezu pululana pri fermentacijama na kiselom hidrolizatu treseta. U cilju poređenja, za sorpciju teških metala iz galvanskih otpadnih voda, osim Aureobasidium pullulans soj CH-1 korišćen je i makroporozni kopolimer, poli(gicidilmetakrilat-co-etilenglikoldimetakrilat) modifikovan sa etilendiaminom, poli(GMA-co-EGDMA)-en. Rezultati uporednih eksperimenata biosorpcije na Aureobasidium pullulans soj CH-1 i sorpcije na polimernom sorbentu su pokazali da se oba postupka mogu uspešno koristiti za uklanjanje teških metala iz galvanskih otpadnih voda. Pokazalo se da je pri datim eksperimentalnim uslovima, za uklanjanje cinka uspešniji postupak biosorpcija, dok je poli(GMA-co-F.GDMA)-en znatno efikasniji za uklanjanje bakra iz galvanskih otpadnih voda

The effect of organic selenium on haematological and biochemical parameters of blood and the quality of pheasant breast meat

Th e aim of this study was to determine the eff ect of supplementing food with various concentrations of organic selenium (0.2 and 0.3 mg/kg diet) on the biochemical and haematological parameters of blood and the qual-ity of breast meat of 45 pheasants. Th e pheasants were divided into three groups and fed mixtures containing organic selenium supplementation in the concentrations of 0.2 mg/kg (1st group) and 0.3 mg/kg (2nd group) and a mixture without selenium in a control group (K). Aft er 60 days of the ex-periment, it was determined that the average values of selenium content in the breast meat and blood serum of the 2nd group of pheasants which were fed 0.3 mg/kg of organic selenium were signifi cantly higher (p < 0.05) than the same parameters of the pheasants from K group. Th e pheasants from the 2nd group also had better sensory traits of meat and they had the highest diff erence of the sum of the ranks of meat acceptability. Th e diff erence was by 15 points higher than that in the K group and 7 points higher than in the meat of the pheasants from the 1st group that fed 0.2 mg/kg of selenium. Th e addition of organic selenium supplementation to the diet for the 2nd group of pheasants (0.3 mg/kg) increased the water retention capacity in breast meat by 0.75% compared to the K group, namely by 0.58% in comparison to the 1st group. Th e average values of chemical parameters of meat (pH, water, fat, proteins and ash content), haematological parameters of pheasant blood (number of erythrocytes, leucocytes and platelets, haemoglobin and haem-atocrit values) and biochemical parameters of blood serum (glucose, en-zymes: aspartate transaminase and alanine aminotransferase, total protein concentration, total cholesterol albumin, triglycerides, calcium, potassium and sodium) were within the limits of reference values for pheasants and very uniform without signifi cant variations among experimental groups

Poređenje biosorpcije sa Aureobasidium pullulans soj CH-1 i polimer sorpcije na Poli(GMA-co-EGMA)teških metala iz otpadnih voda

The intact microbial cells as well as derived microbial products can be highly efficient bioacummulators of both soluble and participate forms of metals, especially from dilute external concentrations (1,2). The reason for testing Aureobasidium pullulans as a biosorbent is the fact that this fungus presents a ubiquitous saprophite that occurs commonly in the phytoshere (3). Therefore, it has enabled the use of carbohydrate wastes as substrates for the production of pullulan such as the peat hydrolysate. The metal removal and recovery processes include: precipitation, adsorption and biosorption, electrowinning and electocoagulation, cementation, membrane separation, solvent extraction and ion exchange (4). Galvanic waste effluent contain heavy metals ions, such as Cu2f, Cr1+, Cr6+, Cd2+, Ni2+, etc., which present environmental hazard. Having all this in mind, the aim of this paper is to examine the possibility of applying Aureobasidium pullulam CH-1 (Collection of Microorganisms, IChTM) as a biosorbent of metals and biosynthesis of pullulan at the same time on peat hydrolisate, distribution of sorbed metals between biomass and pullulan, as well as the correlation between biosorption Aureobasidium pullulam CH-1 and polymer sorption on poly(GMA-co-EGDMA)-en of heavy metals from galvanic waste effluent.Ispitivanje Aureobasidium pullulans, soj CH-1 kao biosorbenta je urađeno na kiselom hidrolizatu treseta sa lokaliteta Vlasinskog jezera. Kiseli hidrolizat treseta je dobijen na isti način kao i otpadne vode pri industrijskoj obradi treseta. Rezultati su pokazali da Aureohusidium pullulans, soj CH-1 može istovremeno da vrši biosorpciju metala i biosintezu pululana pri fermentacijama na kiselom hidrolizatu treseta. U cilju poređenja, za sorpciju teških metala iz galvanskih otpadnih voda, osim Aureobasidium pullulans soj CH-1 korišćen je i makroporozni kopolimer, poli(gicidilmetakrilat-co-etilenglikoldimetakrilat) modifikovan sa etilendiaminom, poli(GMA-co-EGDMA)-en. Rezultati uporednih eksperimenata biosorpcije na Aureobasidium pullulans soj CH-1 i sorpcije na polimernom sorbentu su pokazali da se oba postupka mogu uspešno koristiti za uklanjanje teških metala iz galvanskih otpadnih voda. Pokazalo se da je pri datim eksperimentalnim uslovima, za uklanjanje cinka uspešniji postupak biosorpcija, dok je poli(GMA-co-F.GDMA)-en znatno efikasniji za uklanjanje bakra iz galvanskih otpadnih voda

Bioaccumulation of metallic trace elements and antioxidant enzyme activities in Apfelbeckia insculpta (L. Koch, 1867) (Diplopoda: Callipodida) from the cave Hadži-Prodanova Pećina (Serbia)

The concentration of 10 metallic trace elements or MTE (Cu, Fe, Zn, Mn, As, Hg, Pb, Cd, Ni, and Cr) was measured in specimens of the troglophilic millipede Apfelbeckia insculpta (L. Koch, 1867) and sediment of the cave Hadži-Prodanova Pećina in western Serbia. Some MTE, like Fe and Mn, displayed much higher concentrations compared to other elements, both in the sediment and in the body of A. insculpta. On the other hand, estimation of the bioaccumulation factor (BAF) in both males and females of A. insculpta showed values greater than 1 for xenobiotic elements compared to those that are essential. In addition to chemical analyses, we examined the activities of antioxidant enzymes (SOD, CAT, GPX, and GR) and the phase II biotransformation enzyme GST, as well as the content of –SH groups, in the body of A. insculpta. Activities of two (GR and GST) out of the five tested enzymes showed significant differences between the sexes. These results represent the first comprehensive report of antioxidant enzymes in myriapods. The noted differences in the investigated MTE and enzyme activities between the sexes of A. insculpta most likely reflect different metabolic activities and responses to environmental conditions in males and females.International Journal of Speleology (2017), 46(1): 99-10

Sinteza, NMR i DFT proračunavanja i ispitivanje antimikrobne aktivnosti Zn(II) kompleksa sa N-benziloksikarbonil-S-alaninom

In this study, the first complexes of Zn(II) with the N-benzyloxycar- bonyl-S-alaninato ligand (N-Boc-S-ala) were synthesized. The new complexes were characterized by elemental analysis, conductometric measurements, IR, 1H-NMR, 13C-NMR and 2D-NMR spectroscopy. On the basis of the experimental data, tetrahedral geometry of the Zn(II) complexes was proposed. A very good agreement between the NMR and DFT calculated data was obtained. Investigation of antimicrobial activity of the newly synthesized complexes was also performed. It was established that [Zn(N-Boc-S-ala)2] was selective and acts only on Candida albicans.U ovom radu su sintetizovani prvi kompleksi Zn(II) sa N-benziloksikarbonil-S-alaninato ligandom (N-Boc-S-ala). Kompleksi su okarakterisani elementalnom analizom, konduktometrijskim merenjem, IR, 1H-NMR, 13C-NMR i 2D-NMR spektroskopijom. Tetraedarska geometrija Zn(II) kompleksa pretpostavljena je na osnovu eksperimentalnih podataka. Dobijeno je veoma dobro slaganje između NMR i DFT podataka. Ispitivana je antimikrobna aktivnost novosintetizovanih kompleksa. Ustanovljeno je da je [Zn(N-Boc-S-ala)2] kompleks selektivan i da deluje samo na gljivu Candida albicans