Pathogen Immune Evasion Strategies Quiz

Ribosomes

• 70S ribosomes comprise of 50S large subunit and 30S small subunit.

Taxonomic Rank

• Genus and species are commonly used taxonomic ranks.

Molecular Relationship

• DNA-DNA hybridization is used to determine the closeness of relationship between various bacteria at the molecular level.

Cell Shapes

• Helical shape is not among the cell shapes that occur among unicellular true bacteria.

Drug Targets

• Bacterial cell walls are frequent drug targets.

Bacterial Toxins

• Bacterial toxins inhibit host cells by ADP-ribosylation, proteolysis, or pore formation.

Vibrio cholerae

• Clinical feature associated with Vibrio cholerae infection is profuse, watery diarrhea.
• Vibrio cholerae causes cholera disease.
• Primary treatment for Vibrio cholerae infection is fluid replacement.
• Vibrio cholerae exhibits polar flagella motility.

Pathogenic Microorganisms

• Primary purpose of evading host defenses for pathogenic microorganisms is to establish infection.
• Streptococcus mutans exhibits specificity (tropism) for tooth surfaces.

Bacterial Attachment

• Adhesins determine the tissue specificity (tropism) of bacterial attachment to host cells.

Portal of Entry

• Skin is commonly associated with pathogenic microorganisms transmitted by insect vectors.

Shedding

• Main purpose of shedding from the body for pathogenic microorganisms is to spread infection.

Bacterial Capsules

• Main function of bacterial capsules is to protect against phagocytosis and desiccation.
• Capsule of Bacillus anthracis is composed of D-glutamic acid.

Biofilms

• Bacteria form biofilms to protect against environmental stresses and host defenses.

Immune Evasion Strategies

• Molecular mimicry is an immune evasion strategy used by bacteria to evade host defenses.
• Effect of molecular mimicry is to evade immune recognition.
• Changes in DNA sequence lead to antigenic variation by altering the amino acid sequence of surface antigens.

Motility

• Taxis is the term for directional motility mediated by the flagellum.
• Twitching motility occurs via retraction and extension of the pilus.
• Examples of bacteria that exhibit flagella-independent motility include Mycoplasma and Synechocystis.
• Gliding motility is the term for the form of solid surface translocation exhibited by bacteria.

N. gonorrhoeae

• Mechanism of antigenic variation for N. gonorrhoeae pilin is through gene conversion and point mutations.
• Variable region pilS in N. gonorrhoeae is required for pilus assembly and function.

Immune Evasion

• Many bacteria utilize antigenic variation as an immune evasion strategy to avoid detection.
• Role of molecular mimicry in bacteria is to evade immune recognition by mimicking host molecules.
• Sialic acid is commonly found on the surface of Neisseria and Haemophilus, contributing to their molecular mimicry.

Bacteria Characteristics

• Size range of bacteria is 0.5-5.0 μm.
• Genetic organization of bacteria is typically circular and single-chromosomal.
• Function of plasmids in bacteria is to provide additional genetic information.
• Peptidoglycan is the most commonly found component in the cell wall of bacteria.
• Typical morphology of E. coli is rod-shaped.
• Prokaryotic organisms lack membrane-bound organelles.
• Primary genetic material in bacteria is double-stranded DNA.
• Structure where the DNA is located in bacterial cells is the nucleoid.
• Size range of E. coli is 2-3 μm.