Učinak nanočestica srebra na antioksidacijski odgovor alge Chlorella vulgaris

master's thesis

• Title (english): The effect of silver nanoparticles on antioxidant response of Chlorella vulgaris
• Author: Katarina Terlević
• Mentor: Biljana Balen (mentor)
• Committee member: Biljana Balen (predsjednik povjerenstva)
• Committee member: Ines Radanović (član povjerenstva)
• Committee member: Vesna Petrović Peroković (član povjerenstva)
• Committee member: Draginja Mrvoš-Sermek (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2020-09-24, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Zbog svojih antimikrobnih svojstava, nanočestice srebra (AgNP) mogu se naći u velikom broju potrošačkih proizvoda. S ciljem razumijevanja odgovora na oksidacijski stres uzrokovan toksičnim učinkom AgNP u stanicama zelenih algi, kultura alga Chlorella vulgaris izložena je djelovanju 5, 10 i 20 μM AgNP, stabiliziranih omotačem od polivilpirolidona (AgNP-PVP), u trajanju od 24 h. Spektrofotometrijski je ispitana stabilnost AgNP u hranjivoj podlozi BBM prije izlaganja alge C. vulgaris te stabilnost u kulturi alga u vremenskom periodu od 24 h. U otopinama čestica AgNP u hranjivoj podlozi zabilježen je porast apsorbancije i pomak pika prema manjim valnim duljinama za sve ispitane koncentracije AgNP u usporedbi s rezultatima dobivenim u Milli Q vodi, što pokazuje da je došlo do djelomične agregacije čestica AgNP, ali i otpuštanja iona Ag+. Smanjenje prirasta kulture alge, izmjereno pri najvećoj testiranoj koncentraciji AgNP, ukazalo je na inhibiciju rasta stanica, dok je smanjenje vijabilnosti stanica, povećanje sadržaja MDA i proteinskih karbonila, zabilježeno na većini ispitanih koncentracija AgNP-PVP, pokazalo pojavu oksidacijskog stresa. Oksidacijski stres potvrdila je i povećana aktivnost antioksidacijskog enzima PPX u svim tretmanima, dok je analiza izoformi nakon elektroforeze proteina u nativnim uvjetima pokazala promjenu u ekspresiji sva tri analizirana antioksidacijska enzima (CAT, PPX i APX).

Abstract (english)

Due to their antimicrobial properties, silver nanoparticles (AgNPs) can be found in various consumer products. For better understanding of oxidation stress response and toxic effect of AgNPs on green algae, Chlorella vulgaris was exposed to 5, 10 and 20 μM AgNPs stabilized with polyvinylpyrrolidone coating (AgNP-PVP) for 24 hours. The stability of AgNPs was determined spectrofotometrically in BBM nutrient medium before the exposure to AgNPs and upon exposure of algal culture for 24 h. Increase in the apsorbance value and shift of the peak position toward lower wavelenghts, recorded in all tested AgNP solutions in BBM medium compared to results obatined in Milli Q water, indicated partial AgNP aggregationa as well as release of Ag+ ions. Decrease in growth rate was detected at the highest applied AgNP concentration, which suggested growth inhibiton. Reduced cell viability as well as increased content of MDA and protein carbonyls, detected at all tested AgNP concentrations, showed the presence of oxidatative stress. Additional confirmation was achived by significant increase in activity of PPX, an important antioxidant enzyme. Moreover, changes in isoenzyme patterns of all analysed antioxidant enzymes (CAT, PPX and APX) were recorded in algae cells upon protein analyses by means of gel electrophoresis in native conditions.

• Keywords: alge; reaktivni oblici kisika; prirast kulture; lipidna peroksidacija; oksidacija proteina; antioksidacijski enzimi
• Keywords (english): algae; reactive oxygen species; growth rate; lipid peroxidation; protein oxidation; antioxidative enzymes
• Language: croatian
• URN:NBN: urn:nbn:hr:217:136696
• Study programme: Title: Integrated undergraduate and graduate university study of Biology and Chemistry Education; specializations in: Integrated undergraduate and graduate university study of Biology and Chemistry Education; Course: Integrated undergraduate and graduate university study of Biology and Chemistry Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije biologije i kemije (magistar/magistra edukacije biologije i kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-10-02 07:59:13