Djelovanje gama zračenja na mikobiotu papira

master's thesis

• Title (english): Gamma-irradiation effect on mycobiota of paper materials
• Author: Lucija Sinčić
• Mentor: Maja Šegvić Klarić (mentor)
• Committee member: Maja Šegvić Klarić (predsjednik povjerenstva)
• Committee member: Daniela Jakšić (član povjerenstva)
• Committee member: Katarina Marušić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of microbiology); Zagreb
• Defense date and country: 2018-09-24, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Pharmacy

Abstract

Veliki dio kulturne baštine čine objekti od papirnatih materijala. Kao takvi izrazito su podložni kontaminaciji gljivicama koje svojim djelovanjem ubrzavaju njegovo propadanje. Jedna od najpogodnijih metoda za zaustavljanje destruktivnog djelovanja gljivica je gama zračenje. U ovom je radu ispitivan utjecaj gama zračenja na prirodnu mikobiotu papira te utjecaj na inokuliranog sekundarnog kolonizatora, vrstu Cladosporium sphaerospermum. Uzorci su tretirani pomoću izvora u Laboratoriju za radijacijsku kemiju i dozimetriju (LRKD) Instituta Ruđer Bošković (IRB). Primijenjene su apsorpcijske doze od 2, 7, 20 i 50 kGy u dvije brzine zračenja 0,1 Gy/s i 8,6 Gy/s. Mikrobiološka analiza ozračenih uzoraka provedena je neposredno nakon zračenja te 14., 28., i 56. dan nakon zračenja.
Učinak gama zračenje ovisan je o dozi i o brzini doze. Iz dobivenih rezultata vidljivo je da najniža doza od 2 kGy nije učinkovita u redukciji plijesni ni pri nižoj ni pri višoj brzini doze. Dok su veće doze od 7, 20 i 50 kGy pri višoj brzini učinkovito reducirale i prirodnu mikobiotu i inokuliranu vrstu C. sphaerospermum. To potvrđuje i izračunata vrijednost D10 (decimalna redukcijska doza), odnosno doza potrebna da se inaktivira 90% od početnog broja plijesni u uzorku, koja za C. sphaerospermum i brzinu zračenja 0,1 Gy/s iznosi 11,29 kGy, a za brzinu 8,6 kGy iznosi 4,35 kGy. Potrebno je dakle naći odgovarajuću dozu koja će reducirati mikroorganizme na prihvatljivu razinu, a istovremeno imati minimalni negativni učinak na kemijski sastav papira stoga su u tom području potrebna daljnja ispitivanja.
Za učinkovitu je primjenu gama zračenje u konzervaciji papirnatih objekata kulturne baštine potreban interdisciplinarni pristup.

Abstract (english)

Major part of cultural heritage is made up of paper-based materials. As such, they are highly susceptible to fungal contamination, which causes paper to decay. One of the most convenient methods of stopping the destructive action of fungi is gamma irradiation. This paper was aimed to assess the influence of gamma irradiation on the naturally occurring mycobiota as well as artificially inoculated secondary colonizer Cladosporium sphaerospermum. Inoculated samples have been treated by the Laboratory for radiation chemistry and dosimetry of Ruđer Bošković Institute source. Doses of 2, 7, 20 and 50 kGy were applied at two dose rates of 0,1 and 8,6 Gy/s. Microbiological analysis of irradiated samples was conducted immediately after radiation and on 14, 28 and 56 days after radiation.
Fungicidal effect of gamma radiation was dose and dose rate-dependent. From the obtained results it is apparent that the lowest dose of 2 kGy is not effective in reducing mold at either lower or higher dose rates. While higher doses of 7, 20 and 50 kGy at higher dose rate effectively reduced the naturally occurring mycobiota as well as artificially inoculated secondary colonizer C. sphaerospermum. This is also confirmed by the calculated value D10 (decimal reduction dose), the dose required to inactivate 90% of the initial number of molds in the sample, which is 11.29 kGy for C. sphaerospermum and the rate of radiation 0.1 Gy/s, and for 8.6 kGy is 4.35 kGy. Thus, it is necessary to find an appropriate dose which will reduce the microorganisms to an acceptable level while at the same time will have a minimal negative effect on the chemical composition of the paper, so further testing in this area is required.
To conclude, for the efficient use of gamma irradiation in conservation of paper-based cultural heritage objects, an interdisciplinary approach is needed.

• Keywords: kulturna baština; gama zračenje; papir; plijesni
• Keywords (english): cultural heritage; gamma irradiation; paper; moulds
• Language: croatian
• URN:NBN: urn:nbn:hr:163:962260
• Study programme: Title: Pharmacy; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra farmacije (magistar/magistra farmacije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-09-26 12:12:24