Učinak nanočestica bakrovog oksida na oksidacijski stres u slatkovodnoj algi Chlorella vulgaris

master's thesis

• Title (english): Effect of copper oxide nanoparticles on oxidative stress in the freshwater alga Chlorella vulgaris
• Author: Dorian Loknar
• Mentor: Petra Peharec Štefanić (mentor)
• Mentor: Bruno Komazec (komentor)
• Committee member: Petra Peharec Štefanić (predsjednik povjerenstva)
• Committee member: Mirjana Pavlica (član povjerenstva)
• Committee member: Tomislav Ivanković (član povjerenstva)
• Committee member: Biljana Balen (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2024-02-23, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Bakar je važan metal sve zastupljeniji u obliku nanomaterijala u svakodnevnom životu. Intenzivna proizvodnja i korištenje materijala koji sadrže nanočestice bakra dovodi do otpuštanja tih čestica u okoliš što predstavlja potencijalnu opasnost za žive organizme zbog njihove visoke reaktivnosti i toksičnosti. Zelena alga Chlorella vulgaris je uvriježeni modelni organizam u ekotoksikološkim istraživanjima. U svom diplomskom radu analizirao sam utjecaj nanočestica CuO i Cu2O te iona bakra (CuSO4) u koncentracijama koje omogućuju preživljenje stanica alge C. vulgaris od 75% nakon 72 sata. Rezultati pokazuju da su nanočestice i ioni bakra značajno povećali razine reaktivnih oblika kisika, što je narušilo integritet biomembrana, dok su nanočestice CuO dodatno izazvale oštećenje proteina u stanicama. Nanočestice bakra nisu značajno utjecale na promjenu aktivnosti antioksidacijskih enzima, dok je ionski bakar značajno inhibirao njihovu aktivnost. Sadržaj reduciranog glutationa se povećao, a razina prolina smanjila nakon svih tretmana što ukazuje na pojačanu pripremu, ali i na kontinuiranu obranu stanica od oksidacijskog stresa. Nakon svih tretmana, ekspresija proteina Hsp70 se nije promijenila, dok se ekspresija proteina Hsp90 značajno smanjila. Izražena plazmoliza i destabilizacija stanične stijenke i membrane prati sve tretmane. Nanočestice CuO i Cu2O nakupljaju se na stanicama alge, u vakuoli te na tilakoidnim membranama. Tretmani s nanočesticama bakra imaju fitotoksičniji učinak na stanice alge u odnosu na tretman ionima bakra. Nanočestice Cu2O bile su fitotoksičnije na stanice alge u odnosu na nanočestice CuO.

Abstract (english)

Copper is an important metal that is increasingly present in everyday life in the form of nanomaterials. The intensive production and use of materials containing copper nanoparticles leads to the release of these particles into the environment, posing a potential risk to living organisms due to their high reactivity and toxicity. The green alga Chlorella vulgaris is an established model organism in ecotoxicological research. In my master thesis, I investigated the influence of CuO and Cu2O nanoparticles and copper ions (CuSO4) in concentrations that enable 75% of the algal cells of C. vulgaris to survive after 72 hours. The results show that copper nanoparticles and ions significantly increase the level of reactive oxygen species, that damage the integrity of biomembranes, while CuO nanoparticles additionally cause protein damage in the cells. Copper nanoparticles had no significant effect changing the activity of antioxidant enzymes, while ionic copper significantly inhibited their activity. Reduced glutathione levels increased, and proline levels decreased after all treatments, indicating improved priming but also continuous defense of cells against oxidative stress. After all treatments, the expression of the Hsp70 protein did not change, while the expression of the Hsp90 protein decreased significantly. Pronounced plasmolysis and destabilization of the cell wall and membrane were observed after all treatments. CuO and Cu2O nanoparticles accumulate on algal cells, in the vacuole and on thylakoid membranes. Copper nanoparticle treatments have a more toxic effect on algal cells compared to copper ions. Cu2O nanoparticles were more phytotoxic to algal cells compared to CuO nanoparticles.

• Keywords: zelena alga; reaktivni oblici kisika; antioksidacijski enzimi; proteini toplinskog šoka; ultrastruktura
• Keywords (english): green algae; reactive oxygen species; antioxidant enzymes; glutathione; heat shock proteins; ultrastructure
• Language: croatian
• URN:NBN: urn:nbn:hr:217:144098
• Project: Number: IP-2018-01-5351; Title: Određivanje fizikalno-kemijskih svojstava i toksičnosti nanočestica srebra, bakra i plastike kao potencijalno štetnih novih materijala u obalnim vodama; Acronym: NANO-EMC2; Leader: Daniel Mark Lyons; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Molecular Biology-University graduate programme; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra molekularne biologije (sveučilišni/a magistar/magistra molekularne biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2026-02-23
• Created on: 2024-03-06 13:29:05