Lecture 6.2: Bacterial Virulence Factors 2

Question 1

many bacteria have evolved to become pathogenic by acquiring and maintaining ___

Answer 1

virulence factors

Question 2

what are genetic sources for virulence factors?

Answer 2

plasmids, phage transfer, competence and natural selection

Question 3

many virulence genes are ___

Answer 3

clustered

Question 4

virulence genes are sometimes associated with ____ sequences, suggesting __ transfer

Answer 4

bacteriophage; phage transfer

Question 5

what are pathogenicity islands?

Answer 5

clusters of genes that have been acquired from external environment

Question 6

pathogenicity islands increase ___ in organism

Answer 6

complement of genetic material

Question 7

pathogenic E. coli have many ___ of virulence genes ___

Answer 7

clusters; scattered throughout

Question 8

do virulence genes in E. coli completely replace normal E.coli genes?

Answer 8

no

Question 9

what are 2 colonization factors?

Answer 9

pili and adhesion (possibly flagella)

Question 10

are pili for adhesion present in typical E. coli?

Answer 10

no

Question 11

what is the Locus of Enterocycle Effacement (LEE)?

Answer 11

pathogenicity island associated with intestinal cell attachment and diarrheal disease

Question 12

what are effector proteins?

Answer 12

bacterial proteins that are “injected” into host cells

Question 13

what is the function of effector proteins?

Answer 13

specific functions to alter, hijack and subvert cellular activities

Question 14

what is the causative agent in Cholera?

Answer 14

Vibrio cholerae

Question 15

what is the danger of cholera?

Answer 15

massive dehydration and ion imbalance by diarrhea

Question 16

the cholera toxin is of the ___ type

Answer 16

AB

Question 17

the cholera toxin is ___ to bacteriophage DNA, which suggests__

Answer 17

physically linked; once associated with a bacteriophage

Question 18

toxin co-regualted pilus

Answer 18

the pilus genes have the exact same positive regulator

Question 19

the combined effect of pilus and cholera toxin leads to

Answer 19

replication and massive host diarrhea

Question 20

pathogenic E. coli inserts its own __ for cell attachment

Answer 20

receptor

Question 21

virulence genes are often associated with pathogenesis by encoding __, ___ factors and new methods to inject ___

Answer 21

toxins, secreted; proteins

Question 22

colonization factors mediate attachment to ___ and ___

Answer 22

host cell membrane; specific proteins

Question 23

the LEE is a ____ nucleotide PAI flanked by ___ sequences

Answer 23

40 000; phage

Question 24

the LEE is likely transferred as a __-

Answer 24

single unit

Question 25

the LEE pathogenicity island has a __ system and regulators to control the ___ in the PAI

Answer 25

secretion; genes

Question 26

example of function of effector proteins

Answer 26

actin trafficking

Question 27

the cholera toxin sheds copious amount of ___ in the stool of hosts

Answer 27

new bacteria