izpis_h1_title_alt

Vpliv filogenetske sorodnosti na horizontalni genski transfer med roji sevov Bacillus subtilis
ID Belcijan, Katarina (Author), ID Mandić Mulec, Ines (Mentor) More about this mentor... This link opens in a new window, ID Štefanič, Polonca (Comentor)

.pdfPDF - Presentation file, Download (1,96 MB)
MD5: C00E731501D3E3D16921A5E799B02F07
PID: 20.500.12556/rul/e7281679-4d9f-460d-8871-05285c7f5ead

Abstract
Sorodstvena diskriminacija (razlikovanje) je oblika socialnega vedenja, ko se predstavniki ene vrste vedejo različno do sorodnikov, kot do manj sorodnih predstavnikov. Tudi sevi Bacillus subtilis kažejo zmožnost sorodstvenega razlikovanja, ki se pokaže med rojenjem sevov na površini agarja. Roji nesorodnih (»nonkin«) sevov tvorijo mejno linijo, roji sorodnih (»kin«) sevov pa se združujejo v skupne roje. Med roji »nonkin« sevov prihaja na področju mejne linije do stresnega odziva in celo pobijanja. Na podlagi tega smo predpostavili, da interakcije med roji »nonkin« sevov sprožijo intenzivnejšo izmenjavo DNA na območju mejne linije kot je ta med »kin« sevi. V ta namen smo uporabili seve B. subtilis osamljene iz mikro-talnega okolja in z znano pripadnostjo sorodstvenim skupinam. Vsak sev smo označili z genom za odpornost proti antibiotiku (SpR ali CmR) in s fluorescenčnim označevalcem (cfp ali yfp). To je omogočilo, da smo lahko eksperimentalno sledili horizontalnemu prenosu DNA med sevi s selekcijo transformant odpornih na oba antibiotika. Naši rezultati kažejo, da je delež transformant višji na območju srečanja sevov iz različnih sorodstvenih skupin, kar je v skladu s postavljeno hipotezo. Tudi izražanje gena comGA, ki kodira transporter ComGA, odgovoren za privzem eDNA, je višje na območju srečanja rojev »nonkin« sevov v primerjavi z izražanjem tega gena na stiku »kin« rojev. Zunajcelična DNA (eDNA) je v primerljivi koncentraciji na območju srečanja »kin« in »non-kin« rojev. Vendar do izmenjave DNA med roji ne pride, če na površino agarja nanesemo DNAzo ali uporabimo mutante z okvarjeno kompetenco. Na podlagi tega lahko zaključimo, da je transformacija mehanizem, ki je odgovoren za horizontalni prenos genov med roji sevov.

Language:Slovenian
Keywords:mikrobne združbe, Bacillus subtilis, rojenje celic, medsebojno prepoznavanje, sorodstvena diskriminacija, horizontalni genski transfer
Work type:Master's thesis/paper
Typology:2.09 - Master's Thesis
Organization:BF - Biotechnical Faculty
Publisher:[K. Belcijan]
Year:2017
PID:20.500.12556/RUL-97483 This link opens in a new window
UDC:579.22/.26:579.852.11
COBISS.SI-ID:4849016 This link opens in a new window
Publication date in RUL:26.10.2017
Views:2297
Downloads:426
Metadata:XML RDF-CHPDL DC-XML DC-RDF
:
Copy citation
Share:Bookmark and Share

Secondary language

Language:English
Title:Effects of phylogenetic relatedness of Bacillus subtilis strains on horizontal gene transfer
Abstract:
»Kin« discrimination is a behavior where representatives of the same species behave differentially towards »kin« than toward »nonkin«. This behavior has been mostly studied in humans and social insects. Bacteria Bacillus subtilis also exert differential behavior during swarming forming a dramatic boundary upon meeting the »nonkin« swarm and merging with »kin«. Previous studies indicated stress response and even killing between non-kin cells within the boundary. Considering these findings we hypothesized that interactions between swarms of »nonkin« strains will give rise to more frequent DNA exchange between »nonkin« swarms than between »kin« swarms. We analysed B. subtilis strains with known phylogenetic and »kin« group affiliation that were isolated from a soil microscale. We labelled each strain with a gene for antibiotic resistance (SpR or CmR) and a fluorescent marker (cfp or yfp). This enabled us to experimentally determine the frequency of horizontal gene transfer of DNA between strains by selection for transformants with two antibiotic markers. Our results show that DNA exchange is more frequent at the boundary between »nonkin« than is between »kin«, which is in accordance with the set hypothesis. Also expression of comGA-yfp, coding for the DNA uptake transporter ComGA is higher at the boundary between »nonkin« swarms. Results indicate similar concentrations of extracellular DNA (eDNA) at the meeting point of »kin« and »nonkin« swarms, application of DNase over the agar abolishes DNA exchange and strains defective in competence do not exchange DNA at the meeting point of two swarms. These results provide evidence that transformation is the mechanism responsible for the horizontal gene transfer between swarms and indicate that this evolutionary important process might also be associated with »kin« discrimination.

Keywords:microbial communities, Bacillus subtilis, swarming mutual recognition, kin discrimination, horizontal gene transfer

Similar documents

Similar works from RUL:
Similar works from other Slovenian collections:

Back