Razvoj biofilma bakterije Bacillus cereus na granici voda-zrak

master's thesis

• Title (english): Development of bacterial biofilm of Bacillus cereus at air-liquid interface
• Author: Josipa Ćevid
• Mentor: Tomislav Ivanković (mentor)
• Committee member: Tomislav Ivanković (predsjednik povjerenstva)
• Committee member: Sandra Hudina (član povjerenstva)
• Committee member: Petra Peharec Štefanić (član povjerenstva)
• Committee member: Zoran Tadić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2017-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Bakterija Bacillus cereus je Gram-pozitivna, pokretljiva, štapićasta bakterija koja može biti obligatno aerobna ili fakultativno anaerobna te spada u rod Bacillus. Sveprisutna je u prirodi te je tipični saprofit tla i lako se širi na različite tipove hrane. Endospore su jako hidrofobne i izuzetno otporne na velik broj stresora. Uz to uzrokuje probleme i zbog svoje sposobnosti stvaranja biofilma na različitim supstratima. Bakterijski biofilm je višestanični kompleks formiran od sesilnih zajednica mikroorganizama pričvršćenih na podlogu i uronjenih u matriks koji se sastoji od izvanstaničnih polimernih tvari. Matriks im pruža mehaničku stabilnost, štiti ih od isušenja, djeluje kao prepreka protiv nepovoljnih kemijskih i bioloških utjecaja te pridonosi apsorpciji i skladištenju hranjivih tvari. Glavni cilj ovog istraživanja bio je razviti model stvaranja biofilma bakterije B. cereus na granici voda-zrak te je dokazano da interfaza služi kao mjesto širenja velike količine vegetativnih stanica i endospora. Uz to je potvrđeno da je granica voda-zrak povoljno područje za razvoj i razmnožavanje aerobne ili fakultativno anaerobne bakterije poput B. cereus jer joj pruža pristup kisiku u plinovitoj fazi i hranjivim tvarima u vodenoj fazi.

Abstract (english)

Bacillus cereus is a Gram-positive, motile, rod-shaped bacterium that may be obligatory aerobic or facultatively anaerobic and belongs to the genus Bacillus. It is ubiquitously present in nature and is a typical soil saprofit that easily spreads to different types of food. Endospores are highly hydrophobic and extremely resistant to a large number of stressors. It also cause problems because of its ability to create biofilms on different substrates. Bacterial biofilm is a multicellular complex formed by sessile microorganisms attached to the substrate and immersed in a matrix consisting of extracellular polymeric substances. The matrix provides them with mechanical stability, protects them from desiccation, acts as an obstacle to adverse chemical and biological influences and contributes to the absorption and storage of nutrients. The main purpose of this study was to develop a model for biofilm formation of B. cereus at air-liquid interface and it was proven that the interface serves as a nidus for spreading large amounts of vegetative cells and endospores. It is confirmed that the air-liquid interface is a favorable area for the development and propagation of aerobic or facultatively anaerobic bacteria such as B. cereus because it provides access to oxygen (gaseous) and nutrients (liquid phase).

• Keywords: Bacillus cereus; biofilm; interfaza; matriks; endospora
• Keywords (english): Bacillus cereus; biofilm; interface; matrix; endospore
• Language: croatian
• URN:NBN: urn:nbn:hr:217:384306
• Study programme: Title: Ecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra ekologije i zaštite prirode (magistar/magistra ekologije i zaštite prirode)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-11-13 08:05:55