Bacterial Growth and Nutrition

Question 1

metabolism is relevant because it

Answer 1

• -defines the preferred environment
• -facilitates identification
• -reveals methods for killing or suppressing bacteria

Question 2

exotoxin actions

Answer 2

• damage cellular mb/matrices
• inhibits protein synthesis
• activate secondary messenger paths

Question 3

type III secretory apparatus

Answer 3

• only found in gram - bacteria
• Consists of a channel with a rod that goes through which = lumen. Then there’s a needle and the tip of the needle can interact with, partially enter, and let bacterial proteins be injected into the host cell which then often causes uptake of the bacteria with this apparatus on it

Question 4

direct consequences of pathogen adherence

Answer 4

-cytoskeletal rearrangement, formation of a specialized lesion, and entry into the host cell

Question 5

what is the specific benefit to a pathogen of invasion

Answer 5

• evasion of immune system
• use cell’s resources and machinery
• free from competition with other bacteria
• However, the bacteria could be degraded and then presented on the cell mb to the immune system (bad for pathogen)

Question 6

factors affecting growth rate of bacteria

Answer 6

• medium composition
• temperature (body temp is usually best)
• oxygen

Question 7

which drugs can target DNA synthesis of bacteria and how?

Answer 7

• Novobiocin, quinolines:
• Inhibit gyrase, needed for successful completion of DNA replication
• Gyrase is needed to untangle knots in DNA synthesis- it is present in all cells (humans too) but it is unique in bacteria

Question 8

major cellular targets of antibiotics

Answer 8

• peptidoglycan synthesis
• cell mb
• RNA polymerase
• ribosome inhibitors

Question 9

transcription and translation are _____ in bacteria

Answer 9

coupled

Question 10

penicillin binding proteins

Answer 10

• inhibited by penicillin

- synthesize peptidoglycan by destroying an old strand (gives directionality) and synthesizing 3 new strands

Question 11

siderophores

Answer 11

• A single bacterium can possess multiple siderophore systems, each of which can be active under different environmental systems.
• The genes encoding these systems can be transferred among bacteria.
• Siderophores can be essential for virulence.
• binds the precious co-factor (iron) and takes it into the cell as a complex and then saves the iron and then exudes the siderophore back into the environ
• Siderophoresare amongst the strongest soluble Fe3+binding agents known.

Question 12

any mb that impairs the inner mb will destroy _____ because

Answer 12

• respiration

- because the relevant enzymes for it are compartmentalized in the inner mb

Question 13

enzymes that detoxify active oxygen in bacteria …..

Answer 13

• Are useful for diagnosis
• Can be virulence factors, since they can detoxify host-generated active oxygen
• Give clues for antimicrobial agents

Question 14

generic stress response to starvation

Answer 14

spore formation

Question 15

generic stress response to starvation

Answer 15

synthesis of proteins to protect against heat

Question 16

pathogenesis specific stress responses

Answer 16

-production of toxins and pilli (which allows attachment to host tissues)

Question 17

pathogenesis requires precise control of gene expression: 2 examples

Answer 17

• control of location within the host- ex = S. enterica (dif type III secretions and dif factors required at dif locations)
• control of timing of expression to make virulence factors at the correct time and in the right order: ex = V cholerae (genes for pilus, then attach to wall and then secrete toxin)

Question 18

gene regulation is ___

Answer 18

hierarchial meaning that the controls of gene expression are very complex and have multiple pathways