Synthesis, Structural Characterization and Biological Activity of Functionalized Derivatives of Gum Arabic, Pullulan and Levan Polysaccharides

U okviru ove doktorske disertacije uraĎena je hemijska derivatizacija polisaharida biljnog i mikrobnog porekla u cilju dobijanja novih funkcionalizovanih polimera. Polisaharidi gumiarabika, pululan i levan korišćeni su za sintezu dve grupe konjugata. U prvom delu ovog rada raĎene su oksidativne transformacije polisaharida sa ciljem povećanja njihove reaktivnosti. Tretiranjem polisaharida natrijum-perjodatnim reagensom u vodenom rastvoru uvedene su reaktivne aldehidne grupe u polimerni niz glikana. Perjodatnom oksidacijom gumiarabike i pululana u kontrolisanim uslovima dobijeni su polialdehidni derivati, a variranjem koncentracija polisaharida i oksidacionog sredstva, kao i reakcionog vremena, dobijeni su uzorci različitog stepena oksidacije. Kuplovanjem ovako dobijenih polialdehida gumiarabike i pululana sa polienskim antibioticima u adekvatnim reakcionim uslovima sintetisane su hemijske formulacije nistatina i amfotericina B, sa ciljem povećanja rastvorljivosti ovih antibiotika u vodi. Ispitivanjem antifungalne aktivnosti sintetisanih konjugata dokazano je zadržavanje antimikrobne aktivnosti kuplovanih antibiotika. U drugom delu ovog rada raĎena je hemijska derivatizacija polisaharida pululana i levana kuplovanjem molekula reaktivne antrahinonske boje Remazol Brilliant Blue R za polisaharidne nizove, u baznim uslovima. Sintetisani proizvodi su upotrebljeni kao hromogeni supstrati za odreĎivanje aktivnosti enzima koji selektivno hidrolizuju glikozidne veze karakteristične za ciljne polisaharide, kao i za „screening” mikroorganizama na odreĎenu enzimsku aktivnost direktnom selekcijom na agarnim podlogama...Within the scope of this Doctoral Dissertation the chemical derivatization of polysaccharides of plant and microbial origin was done for the purpose of getting new functionalized polymers. Polysaccharides gum Arabic, pullulan and levan were used for the synthesis of two groups of conjugates. The first section of this paper deals with the oxidative transformation of the polysaccharides aiming to increase their reactivity. By treating the polysaccharides with sodium periodate reagent in aqueous solution the reactive aldehyde groups are introduced into the polymer chain of glycan. Periodate oxidation of gum Arabic and pullulan under the controlled conditions resulted in formation of polyaldehide derivatives, and with the varying concentrations of polysaccharides and oxidizing agent as well as the reaction rate, samples with various levels of oxidation were obtained. By coupling gum Arabic and pullulan polyaldehide, formed in such way, with polyene antibiotics under the adequate reaction conditions, chemical formulations of nystatin and amphotericin B have been synthesized, with the purpose of increasing solubility of these antibiotics in water. The investigation of antifungal activites of the synthesized conjugate has proved that the antimicrobial activity of the coupled antibiotics has been preserved. The second section of this paper describes the chemical derivatization of pullulan and levan polysaccharides by coupling molecules of the reactive Remazol Brilliant Blue R antraquinone dye to polysaccharide chains, under base conditions. Synthesized products were used as chromogenic substrates for the determination of the enzyme activity that selectively hydrolize glycosidic linkages which are typical for the target polysaccharides, as well as for the screening of microorganisms for the specific enzyme activity through direct selection in agar substrates..

MORPHOLOGICAL CHARACTERISTICS OF YEW (TAXUS BACCATA L.) SEEDS FROM URBAN TREES

Taxus baccata L. je retka vrsta u šumama Srbije i uživa status zaštićene vrste kao tercijarni relikt. Nasuprot njenom prirodnom staništu, u parkovima je zastupljena vrsta. Tisa je dvodoma vrsta koja plodonosi svake ili svake druge godine, a seme je okruženo mesnatim crvenim omotačem koji je izuzetno atraktivnog izgleda. Podaci o morfološkim karakteristikama semena tise su ograničeni na mali broj literaturnih izvora usled retkog sakupljanja semena i značajno češćeg razmnožavanja vegetativnim putem. Sa ciljem da se istraži varijabilnost morfoloških karakteristika semena i diverzitet semena tise u urbanim sredinama, izvršeno je sakupljanje semena tokom jeseni 2021. godine sa ukupno 13 stabala tise (11 stabala iz Beograda i po jedno iz Novog Sada i Vrdnika). Morfološke karakteristike semena (dužina i širina semena i prečnik ožiljka na semenu) sa ovih stabala nalaze se u granicama vrednosti koje su prijavljene u literaturi za seme tise. Značajna varijabilnost u karakteristikama semena između posmatranih stabala je dokazana primenom jednofaktorijalne analize varijanse, a potom je izvršeno grupisanje primenom post-hoc Tukey HSD testa. Pojedina stabla koja se prostorno nalaze blizu jedno drugom, pokazala su veći stepen sličnosti semena u odnosu na prostorno udaljena stabla, što je ispitano primenom klaster analize (Tree Clustering, Single Linkage-Euclidean distances).Taxus baccata L. is a rare species in the forests of Serbia and enjoys the status of a protected species as a tertiary relic. In contrast to its natural habitat, this species is widespread in the parks. Yew is a dioecious species that bears fruit every year or every other year, and the seeds are surrounded by a fleshy red covering that is extremely attractive. Data on the morphological characteristics of yew seeds are limited to a small number of literature sources due to the infrequent collection of seeds and significantly more frequent vegetative reproduction. Aiming to investigate the variability of morphological characteristics of seeds and the diversity of yew seeds in urban areas, seed collection was carried out during the fall of 2021 from a total of 13 yew trees (11 trees from Belgrade and one each from Novi Sad and Vrdnik). Morphological characteristics of seeds (length and width of seeds and diameter of seed scar) from these trees are within the range of values reported in the literature for yew seeds. Significant variability in seed characteristics between the observed trees was proven using one-factor analysis of variance, and then grouping was performed using the post-hoc Tukey HSD test. Individual trees that are spatially close to each other showed a higher degree of seed similarity compared to spatially distant trees, which was examined using cluster analysis (Tree Clustering, Single Linkage-Euclidean distances)

Synthesis of gum Arabic-natamycin conjugate

In this work, natamycin, a polyene antibiotic belonging to the family of macrolides, was coupled to the periodate oxidized polysaccharide gum Arabic. Resulting conjugate was characterized by UV-Vis and FT-IR data

Termalna stabilnost konjugata polienskog antibiotika sa polisaharidom

Poster: [https://cer.ihtm.bg.ac.rs/handle/123456789/5057

Termalna stabilnost konjugata polienskog antibiotika sa polisaharidom

Poster presented at XLIX Savetovanja Srpskog hemijskog društva, (13-14. maj 2011., Kragujevac)Abstract: [https://cer.ihtm.bg.ac.rs/handle/123456789/5056

Green synthesis of silver nanoparticles using Bacillus licheniformis strain

The development of eco-friendly technologies in different areas, as well as in nanotechnology, is of great importance to the expansion of the many biological applications of microrganisms. In this work, the synthesis of silver nanoparticles by the reduction of aqueous Ag+ ions using the non-pathogenic bacterial strain B. licheniformis, under mild conditions, was investigated. The synthesized nanoparticles were characterized by UV–Vis spectroscopy, scanning electron microscopy (SEM), and electron diffraction spectroscopy (EDX)

Exopolysaccharides from Bacillus licheniformis: Production, partial characterization and emulsifying activity

The aim of the present study was to compare growth and EPS production of Bacillus licheniformis in two different media, and to partially characterize isolated polysaccharides.Poster: [https://cer.ihtm.bg.ac.rs/handle/123456789/5272

Nutritive and biological values of some Pyrus varieties growing in Serbia

The aim of this study was to characterize twelve different allochthonous varieties of Pyrus species grown on the territory of Serbia. These are: Beurre Clairgeau, Abbate Fetel, General Leclerc, Beurre Bosc, Conference, Beurre d` Hardepont, Williams Christbirne Bartlett, Doyenne du Comice, Kifer, Packham´s Triumph, Curé, Passe Crassane. These varieties are commercial, and have the same origin (Pyrus communis L.). Most of them grows in Serbia since 18th or 19th century, but some of them are new (e.g. Packham's Triumph). Morphological and organoleptic properties, as well as basic chemical composition and energetic values, indicated significant difference between species. This is very important for their potential use in food industry, such as production of juices, sweets, jams, alcoholic beverages, etc.Poster: [https://cer.ihtm.bg.ac.rs/handle/123456789/5274

The treatment of class III malocclusion in early mixed dentition: Two case reports

Class III malocclusion is orthodontic anomaly where mandibular arch is in mesial position to maxillary arch. Reasons for Class III malocclusion can be found in mandibular prognathism, maxillar retrognathism or combination of these two. In most cases of mandibular prognathism, it is necessary to postpone the treatment until the growth ceases. However, if certain conditions are accomplished it is possible to start early treatment of class III malocclusion to improve occlusal relations and provide more favorable environment for future growth. The aim of this study was to present treatment of two patients with Class III maloclussion in early mixed dentition, using two different appliances: Delaire mask and Frankel functional regulator type 3. The treatment with Delaire mask resulted in rotation of maxilla downward and forward due to the angle of extraoral part of the mask to the occlusal plane that was modified to be almost 45°. At the end of the treatment facial esthetics was significantly improved. Moving maxilla forward resulted in straight profile, whereas moving maxilla downward lead to coordination of upper, middle and lower facial third. The result of the treatment in patient who used Frankel functional regulator was correction of anterior crossbite by premaxilla development and incisors protrusion. Significant differences in SNA, SNB and ANB angle values at the beginning and at the end of the treatment were not found suggesting that most changes were dental but not skeletal

Terapija malokluzija III klase u ranoj mešovitoj denticiji - prikaz dva slučaja

Class III malocclusion is orthodontic anomaly where mandibular arch is in mesial position to maxillary arch. Reasons for Class III malocclusion can be found in mandibular prognathism, maxillar retrognathism or combination of these two. In most cases of mandibular prognathism, it is necessary to postpone the treatment until the growth ceases. However, if certain conditions are accomplished it is possible to start early treatment of class III malocclusion to improve occlusal relations and provide more favorable environment for future growth. The aim of this study was to present treatment of two patients with Class III maloclussion in early mixed dentition, using two different appliances: Delaire mask and Frankel functional regulator type 3. The treatment with Delaire mask resulted in rotation of maxilla downward and forward due to the angle of extraoral part of the mask to the occlusal plane that was modified to be almost 45°. At the end of the treatment facial esthetics was significantly improved. Moving maxilla forward resulted in straight profile, whereas moving maxilla downward lead to coordination of upper, middle and lower facial third. The result of the treatment in patient who used Frankel functional regulator was correction of anterior crossbite by premaxilla development and incisors protrusion. Significant differences in SNA, SNB and ANB angle values at the beginning and at the end of the treatment were not found suggesting that most changes were dental but not skeletal.Skeletna malokluzija III klase je nesklad u međusobnom odnosu gornje i donje vilice, jer je donja vilica postavljena mezijalnije u odnosu na gornju. Uzrok nastanka skeletne malokluzije III klase može biti mandibularni prognatizam, maksilarni retrognatizam ili kombinacija ova dva uzroka. U slučaju isuviše razvijene donje vilice najčešće je potrebno sačekati završetak rasta, kako bi se primenilo konačno lečenje. Međutim, ako su ispunjeni određeni uslovi, moguće je primeniti ranu terapiju III klase, da bi se poboljšali okluzalni odnosi i obezbedila dobra osnova za dalji rast. Cilj ovog rada bio je da se prikaže terapijski efekat dva slučaja malokluzije III klase u ranom uzrastu pomoću različitih ortodontskih aparata: Delerove maske i Frenklovog regulatora funkcije tip 3. Kod pacijentkinje koja je tokom lečenja nosila Delerovu masku gornja vilica je zarotirana unapred i nadole, jer je ugao delovanja sile modifikovan da bude skoro 45 stepeni. Na kraju lečenja postignut je znatno bolji izgled lica. Pomeranjem gornje vilice unapred postignut je prav profil, dok je pomeranje nadole dovelo do usklađivanja visine srednje trećine lica sa gornjom i donjom. Kod pacijenta kod kojeg je tokom lečenja primenjena terapija Frenklovim regulatorom funkcije tip 3 do korekcije obrnutog preklopa sekutića došlo je kombinacijom razvijanja premaksile i protruzije sekutića. Značajne promene u vrednostima uglova SNA, SNB i ANB nisu zabeležene na kraju terapije u odnosu na početak, što bi ukazivalo na to da su postignute promene uglavnom dentalne, a ne skeletne