Uloga S-proteina u probiotičkim bakterijama mliječne kiseline

doctoral thesis

• Title (english): The role of S-proteins in probiotic lactic acid bacteria
• Author: Ksenija Uroić
• Mentor: Blaženka Kos (mentor)
• Committee member: Jasna Novak (predsjednik povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2014-12-03, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology
• Universal decimal classification (UDC): 60 - Biotechnology. Genetic engineering. Products of cloning

Abstract

Provedena je izolacija i identifikacija 86 autohtonih sojeva bakterija mliječne kiseline iz tradicionalno proizvedenih fermentiranih proizvoda. Ustanovljeno je da samo četiri soja imaju sloj S-proteina na površini stanica: Lactobacillus plantarum D6, L. brevis ZG1, L. paraplantarum SF9B i L. brevis SF15B te su navedeni sojevi odabrani za daljnja istraživanja u sklopu probiotičkog koncepta. Ustanovljena je uloga S-proteina u preživljavanju simuliranih uvjeta gastrointestinalnog trakta te u agregacijskim i adhezijskim svojstvima odabranih Lactobacillus sojeva. Prisutnost sloja S-proteina na površini stanica Lactobacillus sojeva povećava adheziju na proteine ekstracelularnog matriksa i crijevne epitelne stanice Caco-2 i IPEC-1 staničnih linija te pojačava učinak kompetitivne ekskluzije patogenih sojeva Salmonella Typhimurium FP1 i Escherichia coli ERF 2055 na istim staničnim linijama. Posebno je istražen imunomodulacijski učinak soja L. plantarum D6 te je ustanovljena uloga njegovih S-proteina u poticanju sazrijevanja, odnosno proizvodnje specifičnih citokina u humanim dendritičkim stanicama. Tijekom biotehnološke proizvodnje probiotičkih pripravaka četiri odabrana soja koji eksprimiraju S-proteine, primjenom mikroinkapsulacije i liofilizacije, dobiveni su suhi aktivni pripravci koji sadrže više od 106 CFU/g probiotičkih stanica te je dokazana zaštitna uloga S-proteina tijekom navedenih procesa. Na temelju svih dobivenih rezultata može se zaključiti da prisutnost S-proteina ukazuje na probiotičko djelovanje sojeva roda Lactobacillus koji ih posjeduju.

Abstract (english)

86 autochthonous strains of lactic acid bacteria were isolated from traditionally produced fermented products, identified and characterized. Only four isolates were found to possess S-layer proteins on their cell surface: Lactobacillus plantarum D6, L. brevis ZG1, L. paraplantarum SF9B and L. brevis SF15B, which were selected for further research within the probiotic concept. The role of S-layer proteins of selected strains in survival of simulated conditions of the gastrointestinal tract and in aggregation and adhesion, was proved for all the selected Lactobacillus strains. Furthermore, the presence of S-layer proteins on the cell surface of Lactobacillus strains increases both their adhesion to extracellular matrix proteins and intestinal epithelial cells of Caco-2 and IPEC-1 cell lines and competitive exclusion of pathogens Salmonella Typhimurium FP1 and Escherichia coli ERF 2055. Immunomodulatory properties of the strain L. plantarum D6 were especially studied, indicating the role of its S-proteins in inducing the cytokine production and maturation of human monocyte-derived dendritic cells. During biotechnological production of probiotics using microencapsulation and lyophilisation, active dry products of four strains possessing S-layer proteins contained more than 106 CFU/g probiotic cells, which demonstrates the protective role of the S-layer protein during these processes. Based on the obtained results, it can be concluded that the presence of S-layer proteins indicates probiotic properties of Lactobacillus strains which possess them.

• Keywords: Lactobacillus; probiotici; S-proteini
• Keywords (english): Lactobacillus; probiotics; S-layer proteins
• Language: croatian
• URN:NBN: urn:nbn:hr:159:525927
• Promotion: 2015-07-12
• Study programme: Title: Postgraduate PhD Study in Biotechnology and Bioprocess Engineering; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti (doktor/doktorica znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-05-17 12:04:57