Podcast
Questions and Answers
Which two-component system is essential for Salmonella's survival within macrophages due to low magnesium levels?
Which two-component system is essential for Salmonella's survival within macrophages due to low magnesium levels?
- PhoP/PhoQ (correct)
- EnvZ/PmrA
- PmrA/PmrB
- OmpR/EnvZ
In the context of bacterial adaptation, what is the role of tetraphosphate guanosine during starvation?
In the context of bacterial adaptation, what is the role of tetraphosphate guanosine during starvation?
- It acts as a sensor kinase in two-component systems.
- It directly activates virulence genes.
- It functions as an 'alarmone' signaling starvation. (correct)
- It promotes the transition to the exponential growth phase.
Which two-component system is crucial for both Salmonella infection and Shigella flexneri virulence?
Which two-component system is crucial for both Salmonella infection and Shigella flexneri virulence?
- PhoQ/PmrA
- PhoP/PhoQ
- OmpR/EnvZ (correct)
- PmrA/PmrB
Which of the following correctly describes the sequence of events during bacterial interaction with host cells, as shown in the diagram?
Which of the following correctly describes the sequence of events during bacterial interaction with host cells, as shown in the diagram?
During intracellular infection, what is the immediate precursor to the phagolysosome?
During intracellular infection, what is the immediate precursor to the phagolysosome?
According to the stringent response model, what triggers the production of the alarmone during starvation?
According to the stringent response model, what triggers the production of the alarmone during starvation?
In Legionella pneumophila, which phenotypic switch is associated with the 'transmissive' state?
In Legionella pneumophila, which phenotypic switch is associated with the 'transmissive' state?
What is the role of the sensor kinase in the two-component regulatory systems described?
What is the role of the sensor kinase in the two-component regulatory systems described?
What is the effect of a Salmonella Typhimurium phoP or phoQ null mutation on virulence in mice?
What is the effect of a Salmonella Typhimurium phoP or phoQ null mutation on virulence in mice?
Under which condition are PhoP-repressed genes (prg) induced?
Under which condition are PhoP-repressed genes (prg) induced?
Which of the following is NOT a known consequence of Quorum Sensing in bacteria?
Which of the following is NOT a known consequence of Quorum Sensing in bacteria?
What is the primary function of the PhoP/PhoQ two-component system (TCS)?
What is the primary function of the PhoP/PhoQ two-component system (TCS)?
Which of the following is an example of a PhoP-activated gene product involved in lipid A modification?
Which of the following is an example of a PhoP-activated gene product involved in lipid A modification?
What is the role of autoinducers in quorum sensing?
What is the role of autoinducers in quorum sensing?
What is the effect of low magnesium concentration on PhoP-activated genes (pag)?
What is the effect of low magnesium concentration on PhoP-activated genes (pag)?
What modification to lipid A does the gene pagP encode?
What modification to lipid A does the gene pagP encode?
Which secretion system in Gram-negative bacteria is known for pathogen-host protein transport and is homologous to the flagellar apparatus?
Which secretion system in Gram-negative bacteria is known for pathogen-host protein transport and is homologous to the flagellar apparatus?
Which of the following secretion systems is characteristic of autotransporter functionality?
Which of the following secretion systems is characteristic of autotransporter functionality?
What is the distinctive feature of Type IV secretion systems in Gram-negative bacteria?
What is the distinctive feature of Type IV secretion systems in Gram-negative bacteria?
Which secretion system is specifically related to the transport mechanism similar to bacteriophages?
Which secretion system is specifically related to the transport mechanism similar to bacteriophages?
In which Gram-negative bacteria secretion system is the ESX-1 to ESX-5 associated with vaccine candidates?
In which Gram-negative bacteria secretion system is the ESX-1 to ESX-5 associated with vaccine candidates?
Which of the following is an autoinducer molecule found in Gram-negative bacteria?
Which of the following is an autoinducer molecule found in Gram-negative bacteria?
What is the role of the luxS gene in bacterial communication?
What is the role of the luxS gene in bacterial communication?
What type of signaling molecules do Bacillus spp. produce to interfere with quorum sensing?
What type of signaling molecules do Bacillus spp. produce to interfere with quorum sensing?
In the context of quorum sensing, what is the primary function of the lux operon?
In the context of quorum sensing, what is the primary function of the lux operon?
Which of the following processes is NOT regulated by quorum sensing?
Which of the following processes is NOT regulated by quorum sensing?
Which organism is a key example of symbiosis involving bioluminescence?
Which organism is a key example of symbiosis involving bioluminescence?
What biological function does bioluminescence provide in symbiotic relationships?
What biological function does bioluminescence provide in symbiotic relationships?
Which compound can act as an antipathogenic agent through quorum sensing inhibition?
Which compound can act as an antipathogenic agent through quorum sensing inhibition?
What is the primary focus of quorum sensing?
What is the primary focus of quorum sensing?
Which type of communication is facilitated by the AI-2 autoinducer?
Which type of communication is facilitated by the AI-2 autoinducer?
Which component is NOT associated with Gram-negative bacteria in quorum sensing?
Which component is NOT associated with Gram-negative bacteria in quorum sensing?
What type of system utilizes oligopeptide autoinducers?
What type of system utilizes oligopeptide autoinducers?
Which is NOT a characteristic of the LuxR/LuxI system?
Which is NOT a characteristic of the LuxR/LuxI system?
What role does phospho-LuxO play in Vibrio harveyi?
What role does phospho-LuxO play in Vibrio harveyi?
Which of the following accurately describes diffusion sensing?
Which of the following accurately describes diffusion sensing?
Which organism is known to use the LuxI system for quorum sensing?
Which organism is known to use the LuxI system for quorum sensing?
What is one benefit of using Desia pulchra brominated furanones in relation to biofilms?
What is one benefit of using Desia pulchra brominated furanones in relation to biofilms?
How do treated Pseudomonas aeruginosa biofilms with synthetic furanone C30 appear?
How do treated Pseudomonas aeruginosa biofilms with synthetic furanone C30 appear?
What factor contributes to drug resistance and persistence in biofilms?
What factor contributes to drug resistance and persistence in biofilms?
Which of the following describes phenotypic heterogeneity in biofilms?
Which of the following describes phenotypic heterogeneity in biofilms?
What role does 'bet-hedging' play in mixed-species biofilms?
What role does 'bet-hedging' play in mixed-species biofilms?
Which factor is NOT mentioned as a cue that influences phenotypic heterogeneity?
Which factor is NOT mentioned as a cue that influences phenotypic heterogeneity?
What is the significance of physiological heterogeneity within biofilms?
What is the significance of physiological heterogeneity within biofilms?
What is a potential consequence of the signal reception inhibition in biofilms?
What is a potential consequence of the signal reception inhibition in biofilms?
Flashcards
Desia pulchra
Desia pulchra
A bacterium known for producing brominated furanones that disrupt biofilm formation.
Brominated furanones
Brominated furanones
Compounds that inhibit bacterial communication and biofilm development without selecting for resistance.
Quorum sensing
Quorum sensing
A process where bacteria communicate to coordinate behavior based on population density.
Biofilm structure disruption
Biofilm structure disruption
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Phenotypic heterogeneity
Phenotypic heterogeneity
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Division of labor in bacteria
Division of labor in bacteria
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Physical barriers (EPS)
Physical barriers (EPS)
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AHL signal molecules
AHL signal molecules
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OmpR/EnvZ system
OmpR/EnvZ system
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PhoP/PhoQ system
PhoP/PhoQ system
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Stringent response model
Stringent response model
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Phagocytosis
Phagocytosis
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Phagosome
Phagosome
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Phagolysosome
Phagolysosome
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Exocytosis
Exocytosis
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Nutrient availability
Nutrient availability
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Autoinducers
Autoinducers
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Autoinducer-2 (AI-2)
Autoinducer-2 (AI-2)
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LuxS gene
LuxS gene
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Bioluminescence
Bioluminescence
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Lux operon
Lux operon
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Quorum sensing inhibitors
Quorum sensing inhibitors
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Biofilms
Biofilms
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PhoP/PhoQ TCS
PhoP/PhoQ TCS
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PhoP-activated genes (pag)
PhoP-activated genes (pag)
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PhoP-repressed genes (prg)
PhoP-repressed genes (prg)
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Avirulent mutants
Avirulent mutants
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Covalent lipid A modifications
Covalent lipid A modifications
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Quorum sensing processes
Quorum sensing processes
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Diffusion Sensing
Diffusion Sensing
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AHL (Acylated Homoserine Lactone)
AHL (Acylated Homoserine Lactone)
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AI-2 (Autoinducer 2)
AI-2 (Autoinducer 2)
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LuxR/LuxI System
LuxR/LuxI System
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Two-Component System
Two-Component System
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Phospho-LuxO
Phospho-LuxO
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Type I Secretion System
Type I Secretion System
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Type II Secretion System
Type II Secretion System
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Type III Secretion System
Type III Secretion System
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Type IV Secretion System
Type IV Secretion System
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Type VI Secretion System
Type VI Secretion System
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Study Notes
Microbiology Study Notes
- Microbiology is the study of microorganisms, including bacteria, viruses, fungi, and protozoa.
- A key topic is the regulation of bacterial virulence which is influenced by environmental factors (e.g., temperature, pH, osmolarity), host cells (e.g., contact, intracellular conditions), and bacterial density (quorum sensing) and phenotypic heterogeneity and persistence, and inter-kingdom signaling.
- The central dogma of molecular biology explains how genetic information flows from DNA to RNA to protein, which is vital for understanding regulation. The process involves replication (DNA polymerase), transcription (RNA polymerase), and translation (ribosome).
- Transcriptional regulators such as (RegA, RegB) bind to operator sequences near promoters, as activators or repressors. They are often dimers with helix-turn-helix (HTH) DNA-binding motif.
- Sigma factors bind to different promoters, crucial for regulation, specifically: Sigma-70, Sigma-32, Sigma-54, and Sigma-38.
- Regulation of bacterial virulence is affected by temperature, as in Shigella flexneri and Listeria monocytogenes, through transcriptional and translational regulation, respectively.
- Two-component systems (TCS) are key in regulating bacterial virulence in response to environmental signals like pH, ions, and osmolarity. The systems involve a sensor kinase and a response regulator.
- Bacterial transport encompasses different mechanisms like porins (outer membrane) for small molecules, transporters (plasma membrane) for specific substrates, and siderophores for iron uptake.
- Bacterial secretion systems (type I-VII) are diverse export machinery which are used to transport proteins and toxins out of the cell.
- Quorum sensing is a mechanism in which bacteria coordinate their behaviors by signaling molecules known as autoinducers. This control gene expression and synchronizes behaviours.
- Specific autoinducers such as AHLs (acyl homoserine lactones) are common to intraspecies communication and interspecies interactions (ex. Al-2).
- Biofilms are complex communities of bacteria associated with surfaces, leading to drug resistance; drug tolerance often differs with persistence.
- Inter-kingdom signaling, a phenomenon where bacteria communicate and respond with other organisms, such as eukaryotes, also plays a vital role in pathogenesis. L. pneumophila uses LAI-1 for this.
- Host-controlled signalling compounds like adrenaline and Noradrenaline influence pathogen behaviour.
- Bioluminescence (e.g., in Vibrio fisheri) is a process regulated by quorum sensing, which is linked to symbiotic relationship.
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