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Bacterial Diseases > Virulence Gene Regulation > Flashcards

Virulence Gene Regulation Flashcards

1
Q

What are the 8 common environmental factors driving expression of transcriptional regulation in bacteria

A

temperature

pH

iron availability

other divalent cations Ca++, Mg++, Mn++

carbon and nitrogen sources

cell density: quorum sensing

osmolarity: water availability

oxygen and CO2

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2
Q

What is an operon

A

one promotor controls expression of several genes

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3
Q

What is regulon

A

independent genes whose promoter is controlled by the same regulatory protein

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4
Q

What does sigma factor 70 do

A

housekeeping genes necessary for cell growth

TATAA, TTGACA

N16-19

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5
Q

What does sigma factor 54 do

A

response to nitrogen limiting conditions

TTGCT, TTGGCAC
N5

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6
Q

What does SigV respond to

A

lysozyme stress

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7
Q

How does SigV respond to lysozyme stress

A
  1. a lysozyme is present
  2. the protein is cleaved
  3. sigma factor V binds the cleaved protein
  4. sigmaV is bound to RNA polymerase and is translated into target genes ????
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8
Q

What control RNA polymerase activity

A

transcriptional activators and repressors control RNA polymerase activity

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9
Q

Where do transcriptional activators generally bind

A

generally bind upstream of target promoters

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10
Q

Where do transcriptional repressors generally bind to

A

operator sequences that either overlap promoter sequences or are positioned downstream of the promoter

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11
Q

Where do transcriptional repressors generally bind to

A

operator sequences that either overlap promoter sequences or are positioned downstream of the promoter

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12
Q

When is the diphtheria toxin produced

A

produced in low iron environments

DtxR fur like, represses transcription in the presence of iron

iron regulation of diphtheria toxin

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13
Q

What allows for transcriptional attenuation

A

coupling of transcription and translation in bacteria allows for transcriptional attenuation

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14
Q

What are RNA regulators specifically Thermosensors

A

some RNAs form hairpin structures that unfold as temperature rises

the Shine-Dalagarno sequence is only accessible at high temperatures

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15
Q

A heat shock response is governed by ______

A

RpoH sigma factor 32

is reversible depending on a high or low temperature

high temperature leads to translation

low temperature leads to no translation

????

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16
Q

What do small regulatory RNAs regulate

A

regulate transcription and translation

17
Q

How do small regulatory RNAs work

A

antisense RNA base-pairs to mRNA

usually prevents translation until it is removed by a endonuclease

universal method of gene control that is found in all creatures

18
Q

What can remove a small regulatory RNA to allow for translation

A

endonuclease

19
Q

What type of regulatory molecule is a universal method of gene control that is found in all creatures

A

small regulatory RNAs

20
Q

What is a two-component signal transduction complex

A

a bridge between environmental signals and gene expression

21
Q

What does quorum sensing allow for

A

allows cells to survey their environment

22
Q

What does quorum sensing allow for

A

allows cells to survey their environment for cells of their own kind and involves the sharing of specific small molecules

once there is a sufficient concentration of the signaling molecule is present, specific gene expression is triggered

23
Q

What are autoinducers

A

allow bacteria to determine the relative population size

as population size increases the ore autoinducers are produced

bacteria release small signaling molecules

type of quorum sensing

24
Q

What happens to the amount of autoinducers as bacterial population increases

A

as population size increases the ore autoinducers are produced

25
Q

What are the two main advantages of quorum sneezing

A

delay the production of virulence factors until the host is unable to respond

colonize new areas when the current region is overpopulated

26
Q

Does quorum sensing mechanisms differ between gram negative and gram positive bacteria

A

yes

the signaling systems of gram + and gram - bacteria differ

27
Q

What are examples of gram + autoinducers

A

primarily composed of amino acids

they cannot freely traverse membranes

28
Q

What are examples of gram - autoinducers

A

Autoinducer I (AI-1): freely diffusible, LuxI/R system

Autoinducers 2 (AI-2): universal in bacteria but only a few resound to it, it is sensed by sensor histidine kinase

Bacterial Diseases (8 decks)

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