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Knockout of key matrix components and characterization of their phenotypic effect in Stenotrophonomas maltophilia

Azevedo, Joana Maria (2024) MOBN03 20232
Degree Projects in Molecular Biology
Abstract
Biofilms are intricate bacterial communities prevalent in diverse environments and rely on complex physiological adaptations and interactions to manifest community-intrinsic properties. The biofilm matrix itself is a major contributor to biofilm dynamics, as one of the mediators of the interactions within the biofilm, and it is composed of a diverse array of molecules. This project focuses on Stenotrophomonas maltophilia (SM), a proficient biofilm producer within a synergistic four-species consortium.
To investigate the role of specific matrix components on the biofilm-forming capabilities of this species and, potentially, on the broader community dynamics, we aimed at deleting genes responsible for their synthesis and characterizing... (More)
Biofilms are intricate bacterial communities prevalent in diverse environments and rely on complex physiological adaptations and interactions to manifest community-intrinsic properties. The biofilm matrix itself is a major contributor to biofilm dynamics, as one of the mediators of the interactions within the biofilm, and it is composed of a diverse array of molecules. This project focuses on Stenotrophomonas maltophilia (SM), a proficient biofilm producer within a synergistic four-species consortium.
To investigate the role of specific matrix components on the biofilm-forming capabilities of this species and, potentially, on the broader community dynamics, we aimed at deleting genes responsible for their synthesis and characterizing their biofilm formation abilities in parallel with three other previously available mutants. Our results indicate that optimization of the targeted mutagenesis tools particularly for SM could improve the chances of success in this species. A new mutant strain unrelated to the purposes of this work was isolated. Moreover, characterization of the biofilm formation of the different mutant strains revealed observations similar to other biofilm-forming species in terms of the role of amyloid fibers and flagella. (Less)
Popular Abstract
Home Sweet Biofilm: The Architecture of Microbial Communities

Bacteria frequently live in communities known as biofilms, where they collectively produce and construct a safe place of residence. The community lifestyle gives advantages to the bacteria within as it protects them from predators, stress, and antimicrobial agents, like antibiotics, while maintaining a cohesive community. Understanding how biofilms are structured can give us insight into how we can eradicate them.

Bacteria are traditionally investigated and considered solitary organisms. In nature, much like us, bacteria however build and maintain their own homes where they can live with other individuals, forming biofilms. This can bring them several advantages related... (More)
Home Sweet Biofilm: The Architecture of Microbial Communities

Bacteria frequently live in communities known as biofilms, where they collectively produce and construct a safe place of residence. The community lifestyle gives advantages to the bacteria within as it protects them from predators, stress, and antimicrobial agents, like antibiotics, while maintaining a cohesive community. Understanding how biofilms are structured can give us insight into how we can eradicate them.

Bacteria are traditionally investigated and considered solitary organisms. In nature, much like us, bacteria however build and maintain their own homes where they can live with other individuals, forming biofilms. This can bring them several advantages related to the free-living lifestyle as the biofilm matrix scaffold protects them from environmental threats and makes them more tolerant to stressors such as dehydration and antibiotics. Biofilms can live as free-floating aggregates or form on any surface, and are problematic in the case of infections, as the biofilm itself makes them more difficult to eradicate.

The backbone of the biofilm is the matrix. It acts as a framework where cells can settle in and anchor themselves to surfaces. The matrix is composed of various molecules, such as sugars, proteins, and lipids that bacteria produce themselves. Numerous bacterial species are capable of forming biofilms, as it is the case Stenotrophomonas maltophilia (SM). This soil bacterium is part of a four-species community that has shown a synergistic effect in biofilm formation. However, this effect only happens when all four species are together, as only SM can produce biofilm on its own. Therefore, SM appears to be the major contributor to the biofilm structure of the whole community.

To understand the role of different components of the biofilm matrix in SM, our approach was to delete genes responsible for those components, like removing a building material from a wall, to see if the biofilm falls apart. Although we couldn’t create the mutants as we intended, we identified and characterized a new strain, mSM14 that behaved differently from the original strain.

Previous constructed mutants of this species did however enable biofilm analyses, and by testing them in different nutrient conditions, we could see that the absence of certain genes had variable effects on their capacity to form biofilm. For example, flagella, which are appendages bacteria use for movement, turned out to be important for establishing a dense biofilm.

By optimizing the deletion of genes involved in biofilm formation, we could be able to understand their role not only in the biofilm structure but also in how the biofilm affects the interactions between cells of the same or different species. Ultimately, this understanding could allow us to build a blueprint of biofilm architecture.


Master’s Degree Project in Molecular Biology, 60 credits, 2024
Department of Biology, Lund University

Advisor: Mette Burmølle & Mads Frederik Hansen
Section of Microbiology, Department of Biology, University of Copenhagen (Less)
Please use this url to cite or link to this publication:
author
Azevedo, Joana Maria
supervisor
organization
course
MOBN03 20232
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9176029
date added to LUP
2024-10-03 15:20:32
date last changed
2024-10-03 15:20:32
@misc{9176029,
  abstract     = {{Biofilms are intricate bacterial communities prevalent in diverse environments and rely on complex physiological adaptations and interactions to manifest community-intrinsic properties. The biofilm matrix itself is a major contributor to biofilm dynamics, as one of the mediators of the interactions within the biofilm, and it is composed of a diverse array of molecules. This project focuses on Stenotrophomonas maltophilia (SM), a proficient biofilm producer within a synergistic four-species consortium. 
To investigate the role of specific matrix components on the biofilm-forming capabilities of this species and, potentially, on the broader community dynamics, we aimed at deleting genes responsible for their synthesis and characterizing their biofilm formation abilities in parallel with three other previously available mutants. Our results indicate that optimization of the targeted mutagenesis tools particularly for SM could improve the chances of success in this species. A new mutant strain unrelated to the purposes of this work was isolated. Moreover, characterization of the biofilm formation of the different mutant strains revealed observations similar to other biofilm-forming species in terms of the role of amyloid fibers and flagella.}},
  author       = {{Azevedo, Joana Maria}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Knockout of key matrix components and characterization of their phenotypic effect in Stenotrophonomas maltophilia}},
  year         = {{2024}},
}