UAM | UAM_Biblioteca | Unified search engine | Scientific Production Portal | UAM Research Data Repository
Biblos-e Archivo
    • español
    • English
  • English 
    • español
    • English
  • Log in
JavaScript is disabled for your browser. Some features of this site may not work without it.

Search Biblos-e Archivo

Advanced Search

Browse

All of Biblos-e ArchivoCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsFacultiesThis CollectionBy Issue DateAuthorsTitlesSubjectsFaculties

My Account

Log inRegister

Statistics

View Usage Statistics

Help

Information about Biblos-e ArchivoI want to submit my workFrequently Asked Questions

UAM_Biblioteca

View Item 
  •   Biblos-e Archivo
  • 2 - Trabajos de estudiantes (tesis doctorales, TFMs, TFGs, etc.)
  • Trabajos de estudiantes (tesis doctorales, TFMs, TFGs, etc.)
  • View Item
  •   Biblos-e Archivo
  • 2 - Trabajos de estudiantes (tesis doctorales, TFMs, TFGs, etc.)
  • Trabajos de estudiantes (tesis doctorales, TFMs, TFGs, etc.)
  • View Item

The initial steps of the pLS20 conjugation process: insights into the mechanisms of recipient cell selection and attachment by donor cells

Title (trans.)
Los pasos iniciales del proceso de conjugación del plásmido pLS20: comprensión de los mecanismos de selección y adhesión de células receptoras por parte de las donadoras
Author
Gago Córdoba, César
Advisor
Meijer, Wilfried J. J.
Entity
UAM. Departamento de Biología Molecular; Centro de Biología Molecular Severo Ochoa (CBMSO)
Date
2022-04-07
Subjects
Genética-Tesis doctorales; Genética bacteriana-Tesis doctorales; Biología y Biomedicina / Biología
URI
http://hdl.handle.net/10486/702933
Note
Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de Lectura: 07-04-2022
Esta tesis tiene embargado el acceso al texto completo hasta el 07-10-2023

Licencia de Creative Commons
Esta obra está bajo una licencia de Creative Commons Reconocimiento-NoComercial-SinObraDerivada 4.0 Internacional.

Abstract

Conjugation is the process by which a DNA element is transferred from a donor to a recipient cell through a connecting channel. Conjugation is the principal horizontal gene transfer route that is responsible for the spread of antibiotic resistance, toxin and virulence genes, which is a major global health threat. A better understanding of the conjugation process is required to design strategies or drugs that can impede conjugation-mediated spread of these pernicious genes. Although conjugation occurs in Gram-positive and Gram-negative bacteria, most conjugation studies are based on a limited number of conjugative elements of Gram-negative bacteria. The conjugation process can be divided in different stages that include selection of a plasmid-free recipient cell, attachment of a donor to a recipient cell known as mating pair formation, generation of a connecting channel, and processing and transfer of the DNA from the donor to the recipient cell. Some of these stages appear to be conserved between Gram- negative and -positive bacteria. However, due to the fundamental differences in bacterial cell walls, particularly the initial stages of recipient selection and mating pair formation may be different. Most, if not all, conjugative elements of Gram-negative bacteria produce appendages, named conjugative pili, whose main function is to form mating pairs. Very little is known about mating pair formation by conjugative elements of Gram-positive bacteria. Typical pili associated with conjugation in Gram-negative bacteria have not been observed though for conjugation systems in Gram-positive bacteria suggesting that mating pair formation occurs in a different way(s). The transfer of a conjugative element from one donor to another donor cell affects the efficiency of conjugation. For conjugative elements of Gram-negative bacteria it is has been shown that so-called exclusion systems have evolved that inhibit redundant transfer of conjugative elements between donor cells. Conjugative elements of Gram-positive bacteria are likely to encode also exclusion systems, but these have been studied very little. In this thesis, the initial stages of the conjugation process being mating pair formation and exclusion were studied using the conjugative plasmids pLS20 of the Gram-positive bacterium Bacillus subtilis. Regarding mating pair formation, results were obtained showing that pLS20 contains an exclusion system that is based on a single gene, which we named ses. Ses is the second gene in the large conjugation operon of pLS20 and encodes a surface-located protein. Intriguingly, the level of exclusion is correlated to the amount of Ses protein, and ses is expressed at much higher levels in donor cells having activated the conjugation process than in non-primed donor cells. Due to these differential expression levels, redundant transfer is inhibited very efficiently between two conjugation-primed donor cells, but only moderately between a conjugation primed and non-primed donor cell. Such a differential expression pattern probably occurs also for many or perhaps all other exclusion systems. We propose that that this differential expression serves two purposes: while it favours efficient conjugation, it also allows evolutionary adaptation of conjugative plasmids by not fully blocking redundant transfer. Important progress was also made with respect to mating pair formation of pLS20. It was shown that the seventh gene of the conjugation operon is an adhesion gene containing a thio-ester domain in the N-terminal region of the exported protein. Thio-ester domains are reactive groups permitting the formation of a covalent binding of the protein with another protein via a thio-ester bond. Thio-ester domains have only recently been described to be present in a subgroup of adhesion proteins of Gram-positive bacteria, where they play important roles in adhesion of commensal bacteria to host tissue and in infection o pathogenic bacteria. This is the first time in which an adhesion protein containing a thioester domain has been shown to be crucial for efficient conjugation
Show full item record

Files in this item

Name
gago_cordoba_cesar.pdf
Size
4.400Mb
Format
PDF
Description
Texto de la Tesis Doctoral

Refworks Export

Google™ Scholar:Gago Córdoba, César

This item appears in the following Collection(s)

  • Trabajos de estudiantes (tesis doctorales, TFMs, TFGs, etc.) [19845]

Related items

Showing items related by title, author, creator and subject.

  • Initiation codon selection is accomplished by a scanning mechanism without crucial initiation factors in sindbis virus subgenomic mRNA 

    Garcia-Moreno, M.; Sanz, Miguel Angel; Carrasco, L.
    2015-01-01
  • Selective processing: competitive mechanisms and limits of capacity=Procesamiento selectivo: mecanismos competitivos y límites de capacidad 

    Torralbo Capilla, Ana
    2008
  • The challenge of COVID-19 and hematopoietic cell transplantation; EBMT recommendations for management of hematopoietic cell transplant recipients, their donors, and patients undergoing CAR T-cell therapy 

    Ljungman, Per; Mikulska, Malgorzata; Cámara, Rafael de la; Basak, Grzegorz W.; Chabannon, Christian; Corbacioglu, Selim; Duarte Palomino, RafaelAutoridad UAM; Dolstra, Harry; Lankester, Arjan C.; Mohty, Mohamad; Montoto, Silvia; Murray, John; Peffault de Latour, Régis; Snowden, John A.; Yakoub-Agha, Ibrahim; Verhoeven, Bregje; Kröger, Nicolaus; Styczynski, Jan
    2020-05-13
All the documents from Biblos-e Archivo are protected by copyrights. Some rights reserved.
Universidad Autónoma de Madrid. Biblioteca
Contact Us | Send Feedback
We are onFacebookCanal BiblosYouTubeTwitterPinterestWhatsappInstagram

Declaración de accesibilidad

 

 

All the documents from Biblos-e Archivo are protected by copyrights. Some rights reserved.
Universidad Autónoma de Madrid. Biblioteca
Contact Us | Send Feedback
We are onFacebookCanal BiblosYouTubeTwitterPinterestWhatsappInstagram

Declaración de accesibilidad