Communication - L4A Flashcards
what is signal transduction?
- external signal detected by a surface protein
- then passes through a regulatory machinery
what is a signal?
small organic compound which passes through membranes
Obtains a bioactive response
what do two component regulatory systems: usually contain?
sensor histidine kinase and response regulator
how are microbes social?
- In the lab typically grown in isolation
- Not mimicking natural environment
- Microbes live in heterogeneous communities
what do sensor kinase respond to?
environmental signal and gets phosphorylated?
what is phosphate transferred to?
response regulator which binds to DNA
how does E.coli send osmotic pressure?
- EnvZ senses change in osmotic pressure
- EnvZ autophosphorylates
- EnvZ transfers phosphate to OmpR
what happens when there’s a high osmotic pressure?
phosphorylated ompr REPRESSES transcription of ompF gene and activated ompC transcription
what happens when there’s a low osmotic pressure?
phosphorylated ompR DRIVES transcription of ompF gene
what are examples of global regulatory systems?
- Pho regulon
- Heat shock response
- General stress response
what is quorum sensing?
A regulatory mechanism responding to population density
what is quorum
sufficient numbers
what does quorum sensing control?
- Control of virulence gene expression e.g adhesion proteins, toxins
- Control of biofilm activities
what are biofilms?
- Polymicrobial aggregates
- cells are embedded within self-produced matrix of extracellular polymeric substances (ESPs)
- adhere to each other and/or surface
what is some safety in the biofilm?
- Resistant to antibiotics
- Collective protection
- Nutrition from metabolites
What are autoinducers made from
bacteria in response to an environmental cue
what happens when autoinducres enter another bacteria
they bind to an activator protein driving gene transcription
how do autoinducers work
- produced inside cell and secreted
- enter a new cell
- bind to a response regulator
what is a specialised metabolite
small molecule produced by all cells but not involved in primary metabolism
what do specialised metabolites help bacteria survive
bacteria survive stress
bacteria survive
