Funkcionalnost Levilactobacillus brevis sojeva iz mikrobiote majčinog mlijeka koji eksprimiraju S-proteine

master's thesis

• Title (english): Functionality of S-protein expressing Levilactobacillus brevis strains isolated from human milk microbiota
• Author: Maja Kobeščak
• Mentor: Jasna Novak (mentor)
• Committee member: Andreja Leboš-Pavunc (član povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Antibiotic, Enzyme, Probiotic and Starter Cultures Technology); Zagreb
• Defense date and country: 2021-09-16, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Mikrobiota majčinog mlijeka, koja doprinosi razvoju imunološkog sustava i presudna je za sastav intestinalnog mikrobioma novorođenčeta, značajan je, ali još neistražen izvor probiotičkih bakterija. Cilj ovoga rada je izolacija, identifikacija i analiza funkcionalnih svojstava Lactobacillus sojeva mikrobiote majčinog mlijeka. 16S rDNA sekvenciranjem ustanovljena je učestalost Levilactobacillus brevis između Lactobacillus vrsta mikrobiote majčinog mlijeka. Nakon analize površinskih proteina pomoću SDS-PAGE za daljnja istraživanja odabrana su četiri soja L. brevis MB1, MB2, MB13 i MB20 koji eksprimiraju potencijalne S-proteine. L. brevis MB1, MB2, MB13 i MB20 uspješno se prilagođavaju na simulirane uvjete gastrointestinalnog trakta jer je nakon inkubacije tijekom 6 sati koncentracija bakterijskih stanica iznosila iznad 106 CFU mLˉ¹. S obzirom na to da iskazuju mogućnost autoagregacije iznad 96 % i bakterijske adhezije na otapala, postoji mogućnost uspješne adhezije L. brevis sojeva in vitro. Sva četiri soja iskazuju inhibicijsko djelovanje prema enteropatogenim mikroorganizmima, ali i prema Staphyloccus aureus vrstama, koje su često uzročnik laktacijskog mastitisa. Antistafilokokno djelovanje je značajno funkcionalno svojstvo probiotičkih bakterija, koje ima potencijal bioterapijske primjene. Odabrani L. brevis sojevi sintetiziraju S-proteine, imaju potencijal za kolonizaciju gastrointestinalnog trakta te širok spektar antimikrobnog djelovanja što doprinosi daljnjim istraživanjima funkcionalnosti ovih sojeva.

Abstract (english)

The human milk microbiome impacts the development of an infant's immune system and defines the composition of its first gut microbiota and is significant, but still unexplored source of probiotic bacteria. The main goal of this thesis was to identify and describe the functionality of Lactobacillus strains isolated from human milk microbiota. Levilactobacillus brevis naturally present in human milk microbiota were identified by 16S rDNA sequencing. SDS-PAGE analysis of L. brevis MB1, MB2, MB13 and MB20 surfacome suggests the expression of potential S-proteins. L. brevis MB1, MB2 MB13 and MB20 successfully adapted to the simulated gastrointestinal conditions and after 6 hours incubation survived in the counts of over 106 CFU mLˉ¹. L. brevis MB1, MB2, MB13 and MB20 exerted adhesion ability in vitro since measured autoaggregation of bacterial cells was higher than 96 % and showed bacterial adhesion to solvents. All four strains inhibit enteropathogenic microorganisms, as well as Staphylococcus aureus species, a common cause of lactation mastitis. Antistaphylococcal activity is a significant functional feature of probiotic bacteria, with potential for biotherapeutic use. Selected strains of L. brevis synthesize S-proteins, have the potential to colonize gastrointestinal tract and have a wide range of antimicrobial effects, which contribute to further research of their functionality.

• Keywords: 16S rDNA sekvenciranje; Levilactobacillus brevis; mikrobiota majčinog mlijeka; Sprotein
• Keywords (english): 16S rDNA sequencing; human milk microbiota; Levilactobacillus brevis; S-protein
• Language: croatian
• URN:NBN: urn:nbn:hr:159:193267
• Study programme: Title: Nutrition; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra nutricionizma (magistar/magistra nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-11-17 13:42:17