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Ispitivanje prisustva perzistentnih virusnih infekcija kod pacijenata obolelih od karcinoma kolorektuma u Srbiji
No full textCilj ovog rada je bilo izolovanje i detekcija perzistentnih virusnih DNK molekula, kao faktora
rizika, iz biopsija tkiva pacijenata obolelih od kolorektalnog karcinoma sa i bez prisutnih
metastaza
Sinteza, karakterizacija i ispitivanje potencijalne antitumorske aktivnosti kompleksa gvožđa(III) i nikla(II) sa hidrazonskim ligandom
No full textU ovom radu sintetisani su i rendgenskom strukturnom analizom i infracrvenom spektroskopijom okarakterisani kompleksi Fe(III) i Ni(II) sa hidrazonskim ligandom (E)-2-(2-(1- (6-bromopiridin-2-il)etiliden)hidrazinil)-N,N,N-trimetil-2-oksoetan-1-amonijum hloridom (HLCl). Ligand je ispitan UV-Vis spektroskopijom, infracrvenom spektroskopijom i nuklearno magnetnom rezonancijom. Kod oba kompleksa ligand je tridentatno koordinovan preko NNO donorskog seta atoma. Ispitivana su i potencijalna antitumorska svojstva kompleksa i njihova aktivnost je upoređena sa aktivnošću liganda
Immuno-PCR in the Analysis of Food Contaminants
No full textFood safety is a significant issue of global concern. Consumer safety and government regulations drive the need for the accurate analysis of food contaminants, residues and other chemical constituents of concern. Traditional methods for the detection of food contaminants often present challenges, including lengthy processing times and food matrix interference; they often require expensive equipment, skilled personnel or have limitations in sensitivity or specificity. Developing novel analytical methods that are sensitive, specific, accurate and rapid is therefore crucial for ensuring food safety and the protection of consumers. The immuno-polymerase chain reaction (IPCR) method offers a promising solution in the analysis of food contaminants by combining the specificity of conventional immunological methods with the exponential sensitivity of PCR amplification. This review evaluates the current state of IPCR methods, describes a variety of existing IPCR formats and explores their application in the analysis of food contaminants, including pathogenic bacteria and their toxins, viruses, mycotoxins, allergens, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phthalic acid esters, pesticides, antibiotics and other food contaminants. Depending on the type of analyte, either sandwich or competitive format IPCR methods are predominantly used. This review also examines limitations of current IPCR methods and explores potential advancements for future implementation in the field of food safety
The edaphic factor and orchids: Gymnadenia conopsea from contrasting geologies in the Central Balkans
No full textMain conclusion Two different strategies for the distribution of macro- and trace elements can be observed in the terrestrial orchid Gymnadenia conopsea. Most trace elements are not translocated to the above-ground parts, whereas for macro-elements the trend was reversed, with the highest accumulation in the distal parts of the plants. Abstract Edaphic stress is one of the main factors affecting plant fitness, but it is still poorly understood, even in rare plants such as orchids. Gymnadenia conopsea is a terrestrial orchid that grows on different geological substrates, making it a model species for the study of adaptive responses to edaphic factors, including metals in soil. The samples of plant tissues of G. conopsea growing on carbonate, ultramafic and siliceous substrates in Serbia and the associated rhizosphere soil were collected and analysed for elemental concentrations. Two different strategies for the distribution of macro- and trace elements were found, corresponding to the trend generally observed in orchids. Trace elements (As, B, Cr, Co, Fe, Mn, and Ni) remain mainly in the underground organs and only a small proportion is transferred to the shoots. It was the opposite for the macroelements (Ca, Mg, K and P) with the highest accumulation occurred in the leaves and inflorescences. The tolerance of G. conopsea to the different geological substrates results from the moderate metal concentrations in the soils analysed and the exclusion strategy of the species, which is the most common response to metal induced stress in orchids
Recycling honey bee drone brood for sustainable beekeeping
No full textPollination by insects is vital for global agriculture, with honey bees (Apis mellifera L.) being the most important pollinators. Honey bees are exposed to numerous stressors, including disease, pesticides, and inadequate nutrition, resulting in significant colony losses. This study investigates the use of drone brood to mitigate these problems. Drone brood, which is normally discarded during varroa mite (Varroa destructor, Anderson and Trueman) management, is rich in proteins, fats, and essential minerals. We compared drone brood with an already suggested pollen supplement (Tenebrio [Tenebrio molitor L.] flour). The results indicate that drone brood flour is a viable source of proteins, fats, and minerals and is potentially antimicrobial due to its high content of elements with known antimicrobial properties. It meets the nutritional needs of honey bees while mitigating the effects of varroa mites. The use of drone brood flour can provide high-quality beeswax, surplus of pollen, and improve bee health, which promotes sustainable beekeeping
Uticaj polarnosti sredine na amiloidno agregiranje lizozima
No full textProteini su biomolekuli vrlo složene trodimenzionalne strukture. U fiziološkim uslovima načelno zauzimaju nativnu konformaciju, koja je termodinamički gledano, lokalni energetski minimum. U slučaju destabilizacije izazvane promenom uslova sredine, proteini su skloni građenju različitih tipova agregata. Među njima, ističu se amiloidni fibrili, koji predstavljaju visoko uređenu, termodinamički najstabilniju moguću formu agregata.
Osnovni cilj ovog završnog rada je ispitivanje uticaja različitih uslova koji dovode do amiloidne fibrilacije lizozima na osobine intermedijera i fibrila koji posledično nastaju. Strukturne promene prilikom agregiranja praćene su infracrvenom spektroskopijom sa diferenciranjem intramolekulske β-pločice od intermolekulske agregacione β-pločice. Kinetika i uspešnost formiranja amiloidnih fibrila praćeni su i promenom fluorescencije fluorescentne boje, tioflavina T, koja se specifično vezuje za amiloidne fibrile. Stepen izloženosti hidrofobnih površina intermedijera i fibrilnih formi praćen je promenom fluorescencije fluorofore 8-anilinonaftalen-1-sulfonske kiseline.
Proučavanje amiloidne fibrilacije proteina značajno je iz nekoliko razloga. Prvi je fundamentalni – mehanizam amiloidne fibrilacije i dalje nije poznat. Drugi se tiče potencijalne primene amiloida u različitim granama industrije, dok je treći od značaja za razumevanje patogeneze brojnih bolesti u kojima amiloidne plake igraju ključnu ulogu
Kvantifikacija mikroelemenata i makroelemenata u tkivu nadbubrežne žlezde pacijenata obolelih od Kušingovog sindroma
No full textCilj rada bio je da se pruži pravi uvid o koncentracijama elemenata u tkivu obolelom od Kušingovog sindroma, kao i da se uporedi sadržaj tih elemenata sa sadržajem u kontrolnom tkivu radi dobijanja informacija o mogućim promenama i razlikama između obolelog i zdravog tkiva
Ispitivanje biosinteze levana kod BHET-razgrađujućih mikroorganizama enzimskim određivanjem glukoze
No full textCilj ovog rada je ispitivanje produkcije egzopolisaharida, za šta je korišćeno 9 različitih sojeva mikroorganizama. Postavljena je fermentacija različitih sojeva na podlogama za produkciju levana, kao i na podlogama sa bis(2-hidroksietil) tereftalatom (BHET). Praćen je prinos levana indirektnom metodom iz supernatanta nakon fermentacije pomoću enzimske metode. Na osnovu dobijenih rezultata, zaključeno je da bakterijski soj Bacillus sp. 47, koji je dobar razgrađivač BHET-a, ima najveći prinos levana
Introducing Mineral Chemistry to High School Students: SEM-EDS Analysis of Gadolinite-(Ce)
No full textThe application of Scanning Electron Microscopy – Energy Dispersive X-ray Spectroscopy (SEM-EDS) offers valuable methodological opportunities for introducing high school students to the concept of mineral chemical composition. Integrating multiple-choice questions (MCQs) into this process provides educators with an effective tool for promoting active participation and maintaining classroom engagement [1]. The presented example involves the analysis of SEM-EDS results obtained from a rock sample containing gadolinite-(Ce) [2]. After the EDS spectrum is shown (Figure 1), students are asked to solve a test composed of MCQs. Question 1: Which mineral phase is most likely dominant in this sample? A) Quartz (SiO₂), B) Hematite (Fe₂O₃), C) Gadolinite-(Ce) – (Ce,La,Nd,Y)₂FeBe₂Si₂O₁₀, D) Monazite-(Ce) (CePO₄). Question 2: Which elements in the spectrum most directly support the identification of the dominant mineral phase? A) Ce, Nd, La, Y, Si, Fe, O; B) Si, Al, K, O; C) Fe, S, Mg, C; D) Ca, P, Si, Al. Question 3: Which element(s) would not dissolve during acid digestion (using concentrated HNO₃ and HCl) of the identified mineral phase? A) Fe, Be, O, P; B) Si; C) Y; D) Al, Be. Since Question 3 requires additional knowledge of silicate mineral chemistry and the analytical challenges of silicon quantification (e.g., requiring hydrofluoric acid digestion), it may be omitted or supplemented with further explanation depending on the lesson objective [3]. This educational approach is flexible and can be adapted to various curricula and subjects. With proper instructional support, it provides a meaningful introduction to mineralogical analysis and its relevance to geoscience and material sciences
Microstructural, Morphological, and Magnetic Effects of NiFe2O4 Shell Formation Around Nanospherical ZnFe2O4 Cores
No full textFirst-row transition metal oxides have relatively modest magnetic properties compared to those of permanent magnets based on rare earth elements. However, there is a hope that this gap might be bridged via proper compositional and structural adjustments. Bi-magnetic nanostructures with homogeneous interfaces often exhibit a combination or synergy of properties of both phases, resulting in improved performance compared to their monophasic magnetic counterparts. To gain a deeper insight into these complex structures, a bi-magnetic nanostructured material composed of superparamagnetic nanoparticles comprising a zinc ferrite core and a nickel ferrite shell was synthesized using the seed-mediated growth approach. The resulting ZnFe2O4@NiFe2O4 core–shell nanoparticles were characterized using a series of experimental techniques and were compared to the ZnFe2O4 cores. Most importantly, the formation of the NiFe2O4 shell around the ZnFe2O4 core improved the net crystallinity of the material and altered the particle morphology by reducing the convexity of the surface. Simultaneously, the magnetic measurements demonstrated the coherence of the interface between the core and the shell. These effects combined led to improved spin coupling and stronger magnetism, as evidenced by higher saturation magnetization and the doubling of the blocking temperature for the ZnFe2O4@NiFe2O4 core–shell particles relative to the ZnFe2O4 cores