Konkurenčnost bakterijskih sevov iz rodov Bacteroides in Prevotella v kokulturah pri različnih gojitvenih pogojih

Kozoderc, Nina (author), Accetto, Tomaž (mentor)

V magistrskem delu smo preučevali konkurenčnosti serijskih kokultur več vrst iz rodov Bacteroides in Prevotella pri različnih gojitvenih pogojih. Namen je bil ugotoviti, kateri sevi so bolj konkurenčni pri različnih koncentracijah ksilana in proteinskih hidrolizatov ter ali med izbranimi vrstami obstajajo antagonistične interakcije. Uporabili smo klasične metode striktno anaerobnega dela v kombinaciji z molekularnimi pristopi, kot so sekvenciranje NGS in analiza pridobljenih odčitkov zaporedij gena 16S rRNA. Rezultati so pokazali, da je hitrost rasti posameznih sevov v monokulturah le delno napovedovala prevlado v kokulturah. Poleg tega med izbranimi sevi nismo dokazali antagonizma, zato sklepamo, da je konkurenčnost izbranih sevov odvisna od stopnje učinkovitosti mehanizmov za prevzem in razgradnjo ksilana kot tudi od pretvorbe alternativnih virov ogljika (proteinskih hidrolizatov). V monokulturah so izbrani sevi iz rodu Prevotella, kljub počasni rasti, dosegali višje vrednosti OD600 in tudi prevladali v vseh preizkušenih kokulturah, ne glede na spremembe v količini ksilana, proteinskih hidrolizatov ali vrednosti pH. Na osnovi tega sklepamo, da njihova konkurenčnost temelji tako na učinkovitejših metabolnih mehanizmih kot tudi na boljši prilagodljivosti na spremembe v okolju.

• Language: Slovenian
• Keywords: črevesna mikrobiota, Prevotella, Bacteroides, monokultura, kokultura, sekvenciranje NGS, razgradnja ksilana, razgradnja proteinskih hidrolizatov
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [N. Kozoderc]
• Year: 2025
• PID: 20.500.12556/RUL-167951
• UDC: 579.24/.26:575.112
• COBISS.SI-ID: 229840131
• Publication date in RUL: 21.03.2025

Secondary language

• Language: English
• Title: Competitiveness of Bacteroides and Prevotella bacterial strains in cocultures under different cultivation conditions

Abstract

The master thesis focuses on the study of the competitiveness of serial co-cultures of several Bacteroides and Prevotella species under different cultivation conditions. The aim of the MSc thesis was to determine which strains are more competitive at different concentrations of xylan and protein hydrolysates and whether antagonistic interactions exist between the selected species. We used classical methods of strictly anaerobic work in combination with molecular approaches such as NGS sequencing and analysis of the obtained 16S rRNA sequence reads. The results showed that the growth rate of individual strains in monocultures only partially predicted their dominance in co-cultures. Moreover, no antagonism was detected between the selected strains, suggesting that the competitiveness of the selected strains depends on the efficiency of the xylan uptake and degradation mechanisms and the conversion of alternative carbon sources (protein hydrolysates). In monocultures, the selected Prevotella strains, despite their slower growth rate, achieved higher OD600 values and dominated in all co-cultures tested, irrespective of changes in xylan and protein hydrolysate concentrations or pH value. Based on these findings, we conclude that their competitiveness is based on more efficient metabolic mechanisms and better adaptability to environmental changes.

• Keywords: gut microbiota, Prevotella, Bacteroides, monoculture, co-culture, NGS sequencing, xylan degradation, degradation of protein hydrolysates