Bacterial Invasion Strategies and Lysosome Avoidance, part 1, level easy

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Questions and Answers

What is the role of exoenzymes or toxins produced by pathogens?

  • Cause host tissues to reject the pathogen
  • Prevent adhesion to host tissues
  • Aid in pathogen dissemination throughout the body (correct)
  • Enhance the immune system response

Why are bacterial pathogens living inside host cells shielded from humoral antibodies?

  • Due to the presence of exoenzymes
  • They are primarily eliminated by a cellular immune response (correct)
  • Because they inhibit the production of antibodies
  • They actively target and destroy antibodies

What distinguishes obligate intracellular pathogens from facultative intracellular pathogens?

  • Method of transmission
  • Presence of specific virulence factors
  • Resistance to antibiotics
  • Ability to reproduce only inside host cells (correct)

Which of the following is a facultative intracellular pathogen?

<p>Salmonella (B)</p> Signup and view all the answers

How do pathogens like Listeria gain access to the cytosol of adjacent cells?

<p>By forming membrane protrusions that resolve into vacuoles (D)</p> Signup and view all the answers

Which surface receptors do Listeria's internalins InlA and InlB interact with during host cell invasion?

<p>E-cadherin and Met (B)</p> Signup and view all the answers

How does Listeria escape from the phagosome in host cells?

<p>Through the action of secreted proteins, LLO, and PI-PLC (C)</p> Signup and view all the answers

What facilitates the unidirectional movement of Listeria within host cells?

<p>Actin polymerization (A)</p> Signup and view all the answers

What is the primary difference between the 'trigger' and 'zipper' mechanisms of bacterial entry into host cells?

<p>The trigger mechanism involves effector proteins while the zipper mechanism relies on surface proteins. (C)</p> Signup and view all the answers

Which type of cell does the text mention as one of the most efficient in antimicrobial defense?

<p>Macrophages and DCs (A)</p> Signup and view all the answers

What do Salmonella and Shigella use to induce membrane ruffles in intestinal epithelial cells?

<p>Effector proteins (D)</p> Signup and view all the answers

How does Yersinia pseudotuberculosis invade host cells?

<p>By secreting effector proteins to trigger entry (D)</p> Signup and view all the answers

Which bacteria use a 'zipper' mechanism for invading host cells?

<p>Legionella pneumophila (C)</p> Signup and view all the answers

What is the role of the subset of T3SS1 effectors (SipA, SipC, SopB, SopE, SopE2) according to the text?

<p>To induce massive localized rearrangements of actin and the plasma membrane (A)</p> Signup and view all the answers

What is the primary role of outer membrane protein invasion during the infection process?

<p>Binding to host cell integrins (D)</p> Signup and view all the answers

Why is avoiding the lysosome crucial for intracellular survival strategies employed by bacteria?

<p>To prevent being digested by lysosomal enzymes (D)</p> Signup and view all the answers

Which mechanism do bacteria use to subvert phagocytosis and survive within phagocytes like macrophages?

<p>Preventing fusion of phagosome with lysosome (B)</p> Signup and view all the answers

How does Salmonella evade destruction within a phagocyte after being engulfed by macrophages?

<p>Preventing fusion of phagosome with lysosome (A)</p> Signup and view all the answers

Which proteins are produced by Listeria monocytogenes and Shigella to escape phagosomes via lysis?

<p>Virulence factors (B)</p> Signup and view all the answers

What is the significance of IpaB protein in the escape mechanism of Shigella from phagosomes?

<p>Forms ion channels for molecule exchange (D)</p> Signup and view all the answers

Which bacterial species disseminate within non-phagocytic cells via cell-to-cell spread?

<p>Rickettsia spp. (B)</p> Signup and view all the answers

How do most host cells eliminate pathogens taken up through phagocytosis?

<p>Fusing phagosome with lysosome to form a digestive compartment (B)</p> Signup and view all the answers

What is a key challenge faced by intracellular pathogens living in vacuoles?

<p>Remodeling vacuoles for nutrient acquisition (B)</p> Signup and view all the answers

What is the primary mechanism employed by bacteria to avoid intracellular killing in host cells?

<p>Preventing fusion with lysosomes by subverting endosomal trafficking (D)</p> Signup and view all the answers

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