18 Questions
What is the best method to prove the role of a virulence gene according to the molecular version of Koch's postulates?
In-frame deletions or point mutations
Which step of Koch's postulates involves isolating bacteria from diseased but not healthy animals?
Step 1 - Bacteria isolated from diseased but not healthy animals
What method often leads to the identification of auxiliary secretion systems or transcription factors in forward genetics?
Transposon mutagenesis
What is the main purpose of introducing a mutation onto the chromosome of a pathogen in reverse genetics?
To identify virulence genes
Which process involves characterizing putative virulence genes?
DNA sequencing and bioinformatics
What is the phenotype or property under investigation associated with, according to the molecular version of Koch's postulates?
Pathogenic members of a genus or pathogenic strains of a species
What is the significance of positive colonies appearing brick red on an indicator plate?
Lactose fermentation
How does a positive colony on an indicator plate differentiate from a negative one?
Lactose fermentation
In the context of colony morphology, what does 'rough and smooth' refer to in relation to E.coli?
LPS characteristics
What aspect of pathogenesis is reflected by the pigmentation of Staphylococcus aureus colonies?
Anti-oxidant activity
Which tissue culture model involves the extraction and growth of macrophages/DCs from bone marrow?
Primary cell lines
What distinguishes between primary cell lines and immortalized cells in tissue culture models?
Life span
What is the purpose of staining with Diff-Quick in the intracellular growth curve experiment?
To visualize the morphology of the colonies
What is the significance of removing coverslips or hypotonically lysing host cells in the intracellular growth curve experiment?
To facilitate colony counting
How does the process of washing monolayer with antibiotics affect the experiment?
Reduces bacterial contamination
What role does the addition of gentamicin play in the experiment?
To kill extracellular bacteria
Why is it important to determine CFUs (gentamicin-resistant bacteria) during the experiment?
To measure bacterial colony-forming units (CFUs)
In the context of the experiment, what is the purpose of visualizing intracellular growth curves?
To determine antibiotic efficacy against intracellular pathogens
Test your knowledge on differentiating Gram-negative bacteria based on bile salt agar test and lactose fermentation. Learn about the significance of colony morphology variations in pathogenesis. Identify key features of Escherichia coli and Streptococcus pneumoniae.
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