TY  - JOUR
AU  - Šokarda Slavić, Marinela
AU  - Ralić, Vanja
AU  - Nastasijević, Branislav
AU  - Matijević, Milica
AU  - Vujčić, Zoran
AU  - Margetić, Aleksandra
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6460
AB  - Poly(γ-glutamic acid) (PGA), naturally produced by Bacillus species, is a biodegradable, non-toxic, biocompatible, and non-immunogenic negatively charged polymer. Due to its properties, it has found various applications in the food, cosmetic and pharmaceutical industries. In this work, Bacillus subtilis 17B was selected as the best PGA producer among fifty wild-types Bacillus strains tested and characterized as a glutamate-independent producer. The production of PGA by the newly identified strain was optimized and increased tenfold using the Box-Behnken experimental design. The purity of PGA after recovery and purification from the fermentation broth was confirmed by SDS-PAGE followed by Methylene Blue staining. PGA was characterized by ESI MS and used for the preparation of a new nanocomposite with TiO2. The synthesis of PGA/TiO2 nanocomposite, its structural analysis, and cytotoxic effect on the cervical cancer cell line (HeLa cell) was investigated to determine the potential anti-cancer usage of this newly prepared material. Encouraging, PGA/TiO2 nanocomposite showed an increased cytotoxic effect compared to TiO2 alone.
AB  - Поли(γ-глутаминска киселина) (ПГK), коју производе бактерије рода Bacillus, је биоразградив, нетоксичан, биокомпатибилан и неимуноген негативно наелектрисани полимер. Због својих својстава нашао је разноврсну примену у прехрамбеној, козметичкој и фармацеутској индустрији. У овом раду, Bacillus ѕubtilis 17Б је изабран као најбољи ПГК продуцер међу педесетак тестираних природних изолата бактерија из овог рода и окарактерисан као глутамат независтан продуцер. Производња ПГК овим новоидентификованим сојем је оптимизована и десетоструко увећана коришћењем Box-Behnken експерименталног дизајна. Чистоћа ПГК након изоловања и пречишћавања из ферметационе течности је потврђена електрофорезом (SDS-PAGE) након бојења метиленским плавим. ПГК је окарактерисана масеном спекроскопијом (ESI MS) и коришћена за добијање новог нанокомпозита са ТiО2. Синтеза ПГК/ТiО2 нанокомпозита, његова структурна анализа и цитотоксични ефекат на 
ћелијску линију рака грлића материце (HeLa ћелије) је испитан да би се утврдила потенцијална 
употреба овог новодобијеног материјала у борби против ћелија рака. Нанокомпозит ПГК/ТiО2
показао је повећан цитотоксични ефекат на поменуте ћелије рака у поређењу са самим ТiО2.
PB  - Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - A novel PGA/TiO2 nanocomposite prepared with poly(γ-glutamic acid) from the newly isolated Bacillus subtilis 17B strain
T1  - Нови ПГК/TiO2 нанокомпозит добијен од поли(γ -глутаминске киселине) из новоизолованог соја bacillus subtilis 17B
VL  - 88
IS  - 10
SP  - 985
EP  - 997
DO  - 10.2298/JSC221116011S
ER  - 

@article{
author = "Šokarda Slavić, Marinela and Ralić, Vanja and Nastasijević, Branislav and Matijević, Milica and Vujčić, Zoran and Margetić, Aleksandra",
year = "2023",
abstract = "Poly(γ-glutamic acid) (PGA), naturally produced by Bacillus species, is a biodegradable, non-toxic, biocompatible, and non-immunogenic negatively charged polymer. Due to its properties, it has found various applications in the food, cosmetic and pharmaceutical industries. In this work, Bacillus subtilis 17B was selected as the best PGA producer among fifty wild-types Bacillus strains tested and characterized as a glutamate-independent producer. The production of PGA by the newly identified strain was optimized and increased tenfold using the Box-Behnken experimental design. The purity of PGA after recovery and purification from the fermentation broth was confirmed by SDS-PAGE followed by Methylene Blue staining. PGA was characterized by ESI MS and used for the preparation of a new nanocomposite with TiO2. The synthesis of PGA/TiO2 nanocomposite, its structural analysis, and cytotoxic effect on the cervical cancer cell line (HeLa cell) was investigated to determine the potential anti-cancer usage of this newly prepared material. Encouraging, PGA/TiO2 nanocomposite showed an increased cytotoxic effect compared to TiO2 alone., Поли(γ-глутаминска киселина) (ПГK), коју производе бактерије рода Bacillus, је биоразградив, нетоксичан, биокомпатибилан и неимуноген негативно наелектрисани полимер. Због својих својстава нашао је разноврсну примену у прехрамбеној, козметичкој и фармацеутској индустрији. У овом раду, Bacillus ѕubtilis 17Б је изабран као најбољи ПГК продуцер међу педесетак тестираних природних изолата бактерија из овог рода и окарактерисан као глутамат независтан продуцер. Производња ПГК овим новоидентификованим сојем је оптимизована и десетоструко увећана коришћењем Box-Behnken експерименталног дизајна. Чистоћа ПГК након изоловања и пречишћавања из ферметационе течности је потврђена електрофорезом (SDS-PAGE) након бојења метиленским плавим. ПГК је окарактерисана масеном спекроскопијом (ESI MS) и коришћена за добијање новог нанокомпозита са ТiО2. Синтеза ПГК/ТiО2 нанокомпозита, његова структурна анализа и цитотоксични ефекат на 
ћелијску линију рака грлића материце (HeLa ћелије) је испитан да би се утврдила потенцијална 
употреба овог новодобијеног материјала у борби против ћелија рака. Нанокомпозит ПГК/ТiО2
показао је повећан цитотоксични ефекат на поменуте ћелије рака у поређењу са самим ТiО2.",
publisher = "Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "A novel PGA/TiO2 nanocomposite prepared with poly(γ-glutamic acid) from the newly isolated Bacillus subtilis 17B strain, Нови ПГК/TiO2 нанокомпозит добијен од поли(γ -глутаминске киселине) из новоизолованог соја bacillus subtilis 17B",
volume = "88",
number = "10",
pages = "985-997",
doi = "10.2298/JSC221116011S"
}

Šokarda Slavić, M., Ralić, V., Nastasijević, B., Matijević, M., Vujčić, Z.,& Margetić, A.. (2023). A novel PGA/TiO2 nanocomposite prepared with poly(γ-glutamic acid) from the newly isolated Bacillus subtilis 17B strain. in Journal of the Serbian Chemical Society
Serbian Chemical Society., 88(10), 985-997.
https://doi.org/10.2298/JSC221116011S

Šokarda Slavić M, Ralić V, Nastasijević B, Matijević M, Vujčić Z, Margetić A. A novel PGA/TiO2 nanocomposite prepared with poly(γ-glutamic acid) from the newly isolated Bacillus subtilis 17B strain. in Journal of the Serbian Chemical Society. 2023;88(10):985-997.
doi:10.2298/JSC221116011S .

Šokarda Slavić, Marinela, Ralić, Vanja, Nastasijević, Branislav, Matijević, Milica, Vujčić, Zoran, Margetić, Aleksandra, "A novel PGA/TiO2 nanocomposite prepared with poly(γ-glutamic acid) from the newly isolated Bacillus subtilis 17B strain" in Journal of the Serbian Chemical Society, 88, no. 10 (2023):985-997,
https://doi.org/10.2298/JSC221116011S . .

TY  - JOUR
AU  - Nastasijevic, Branislav
AU  - Milošević, Maja
AU  - Janjić, Goran
AU  - Stanić, Vojislav
AU  - Vasić, Vesna
PY  - 2016
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1857
AB  - The extracellular nucleotides act as neurotransmitters and signaling molecules in CNS, binding to a P2X and P2Y receptors. Their concentration regulates a cascade of membrane ecto enzymes, including the ecto-nucleotide triphosphate diphosphohydrolases (E-NTPDases). In many neuropathological conditions, such as neuroinflammatory, epilepsy, depression and migraine, altering of E-NTPDase activity was observed. The objective of this study was to investigate whether Gentiana lutea (G. lutea) extracts affect E-NTPDase activity and which of their constituents (loganic acid, gentiopicroside, isovitexin, amarogentin and isogentisin) exert inhibitory activity. The constituent's concentration in the extracts was determined by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS). Extracts and constituents were tested with E-NTPDase displayed on the rat synaptosomal membrane as well as by molecular docking study. Ethanol water extract (50%, v/v) exerted significant level of inhibition (52%) at concentration of 200 mg mL(-1). By inhibition studies with single constituents about 30% inhibition was achieved in any case, thus the model of one substrate acting on two enzymes was used to determine IC50 values. Molecular docking study revealed amarogentin, isovitexin and isogentisin dimer as the potent E-NTPDase inhibitors with the binding energies ranging from -9.4 to -10 kcal mol(-1) versus -8.0 kcal mol(-1) for ATP. Presence of isogentisin only in ethanol water extracts may explain their better inhibitory acitivities. Findings of this study are useful from the perspective of safety of products based on G. lutea extracts, while investigated constituents belong to secoiridoids and xanthones class of compounds could be considered as a source of potential E-NTPDase inhibitors.
PB  - Asian Network Scientific Information-Ansinet, Faisalabad
T2  - International Journal of Pharmacology
T1  - Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase
VL  - 12
IS  - 4
SP  - 272
EP  - 289
DO  - 10.3923/ijp.2016.272.289
ER  - 

@article{
author = "Nastasijevic, Branislav and Milošević, Maja and Janjić, Goran and Stanić, Vojislav and Vasić, Vesna",
year = "2016",
abstract = "The extracellular nucleotides act as neurotransmitters and signaling molecules in CNS, binding to a P2X and P2Y receptors. Their concentration regulates a cascade of membrane ecto enzymes, including the ecto-nucleotide triphosphate diphosphohydrolases (E-NTPDases). In many neuropathological conditions, such as neuroinflammatory, epilepsy, depression and migraine, altering of E-NTPDase activity was observed. The objective of this study was to investigate whether Gentiana lutea (G. lutea) extracts affect E-NTPDase activity and which of their constituents (loganic acid, gentiopicroside, isovitexin, amarogentin and isogentisin) exert inhibitory activity. The constituent's concentration in the extracts was determined by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS). Extracts and constituents were tested with E-NTPDase displayed on the rat synaptosomal membrane as well as by molecular docking study. Ethanol water extract (50%, v/v) exerted significant level of inhibition (52%) at concentration of 200 mg mL(-1). By inhibition studies with single constituents about 30% inhibition was achieved in any case, thus the model of one substrate acting on two enzymes was used to determine IC50 values. Molecular docking study revealed amarogentin, isovitexin and isogentisin dimer as the potent E-NTPDase inhibitors with the binding energies ranging from -9.4 to -10 kcal mol(-1) versus -8.0 kcal mol(-1) for ATP. Presence of isogentisin only in ethanol water extracts may explain their better inhibitory acitivities. Findings of this study are useful from the perspective of safety of products based on G. lutea extracts, while investigated constituents belong to secoiridoids and xanthones class of compounds could be considered as a source of potential E-NTPDase inhibitors.",
publisher = "Asian Network Scientific Information-Ansinet, Faisalabad",
journal = "International Journal of Pharmacology",
title = "Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase",
volume = "12",
number = "4",
pages = "272-289",
doi = "10.3923/ijp.2016.272.289"
}

Nastasijevic, B., Milošević, M., Janjić, G., Stanić, V.,& Vasić, V.. (2016). Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase. in International Journal of Pharmacology
Asian Network Scientific Information-Ansinet, Faisalabad., 12(4), 272-289.
https://doi.org/10.3923/ijp.2016.272.289

Nastasijevic B, Milošević M, Janjić G, Stanić V, Vasić V. Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase. in International Journal of Pharmacology. 2016;12(4):272-289.
doi:10.3923/ijp.2016.272.289 .

Nastasijevic, Branislav, Milošević, Maja, Janjić, Goran, Stanić, Vojislav, Vasić, Vesna, "Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase" in International Journal of Pharmacology, 12, no. 4 (2016):272-289,
https://doi.org/10.3923/ijp.2016.272.289 . .

TY  - JOUR
AU  - Tomović, Aleksandar Ž.
AU  - Jovanović, Vladimir P.
AU  - Durisic, I
AU  - Cerovski, V Z
AU  - Nastasijevic, B
AU  - Veielovic, S R
AU  - Radulović, Katarina
AU  - Zikić, Radomir
PY  - 2015
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1669
AB  - The photoluminescence (PL) quenching mechanism of UV light and air-exposed amorphous thin films of 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl (DPVBi), a well-known hole-transport material used in organic light-emitting diodes, is studied. Thin films of DPVBi are stable when exposed to UV light in vacuum but tend to degrade if oxygen is present simultaneously. This is evident from the changes in UV-vis absorption spectra of the latter, showing that degradation rate of DPVBi films is linearly proportional to both oxygen concentration and UV light intensity. Mass spectrometry study of such films revealed a number of different oxygen-containing molecules and fragments of DPVBi thus confirming apparent photo-oxidation process. Also, DFT study of molecular DPVBi with and without oxygen was carried out, the IR spectra calculated for the lowest energy molecules found and the results are compared with the experiment. The most sensitive to photo-oxidation is DPVBi photoluminescence, which decays exponentially with respect to the concentration of photo-oxidized DPVBi molecules (impurities). The PL quantum yield of DPVBi thin film drops to a half of its original value for 0.2% of the impurities present, at which point an average distance between DPVBi molecules (the donors) and photo-oxidized DPVBi species (acceptors) is an order of magnitude larger than the separation between two adjacent molecules. This implies a need for a long-range Forster energy transfer, which we rule out based on the lack of a donor-acceptor spectral overlap. The apparent discrepancy can be removed by postulating exciton self-diffusion in DPVBi thin films, for which there is supporting evidence in existing literature.
PB  - Elsevier
T2  - Journal of Luminescence
T1  - Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air
VL  - 167
SP  - 204
EP  - 210
DO  - 10.1016/j.jlumin.2015.06.036
ER  - 

@article{
author = "Tomović, Aleksandar Ž. and Jovanović, Vladimir P. and Durisic, I and Cerovski, V Z and Nastasijevic, B and Veielovic, S R and Radulović, Katarina and Zikić, Radomir",
year = "2015",
abstract = "The photoluminescence (PL) quenching mechanism of UV light and air-exposed amorphous thin films of 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl (DPVBi), a well-known hole-transport material used in organic light-emitting diodes, is studied. Thin films of DPVBi are stable when exposed to UV light in vacuum but tend to degrade if oxygen is present simultaneously. This is evident from the changes in UV-vis absorption spectra of the latter, showing that degradation rate of DPVBi films is linearly proportional to both oxygen concentration and UV light intensity. Mass spectrometry study of such films revealed a number of different oxygen-containing molecules and fragments of DPVBi thus confirming apparent photo-oxidation process. Also, DFT study of molecular DPVBi with and without oxygen was carried out, the IR spectra calculated for the lowest energy molecules found and the results are compared with the experiment. The most sensitive to photo-oxidation is DPVBi photoluminescence, which decays exponentially with respect to the concentration of photo-oxidized DPVBi molecules (impurities). The PL quantum yield of DPVBi thin film drops to a half of its original value for 0.2% of the impurities present, at which point an average distance between DPVBi molecules (the donors) and photo-oxidized DPVBi species (acceptors) is an order of magnitude larger than the separation between two adjacent molecules. This implies a need for a long-range Forster energy transfer, which we rule out based on the lack of a donor-acceptor spectral overlap. The apparent discrepancy can be removed by postulating exciton self-diffusion in DPVBi thin films, for which there is supporting evidence in existing literature.",
publisher = "Elsevier",
journal = "Journal of Luminescence",
title = "Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air",
volume = "167",
pages = "204-210",
doi = "10.1016/j.jlumin.2015.06.036"
}

Tomović, A. Ž., Jovanović, V. P., Durisic, I., Cerovski, V. Z., Nastasijevic, B., Veielovic, S. R., Radulović, K.,& Zikić, R.. (2015). Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air. in Journal of Luminescence
Elsevier., 167, 204-210.
https://doi.org/10.1016/j.jlumin.2015.06.036

Tomović AŽ, Jovanović VP, Durisic I, Cerovski VZ, Nastasijevic B, Veielovic SR, Radulović K, Zikić R. Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air. in Journal of Luminescence. 2015;167:204-210.
doi:10.1016/j.jlumin.2015.06.036 .

Tomović, Aleksandar Ž., Jovanović, Vladimir P., Durisic, I, Cerovski, V Z, Nastasijevic, B, Veielovic, S R, Radulović, Katarina, Zikić, Radomir, "Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air" in Journal of Luminescence, 167 (2015):204-210,
https://doi.org/10.1016/j.jlumin.2015.06.036 . .