Lecture 6.2: Bacterial Virulence Factors 2 Flashcards
many bacteria have evolved to become pathogenic by acquiring and maintaining ___
virulence factors
what are genetic sources for virulence factors?
plasmids, phage transfer, competence and natural selection
many virulence genes are ___
clustered
virulence genes are sometimes associated with ____ sequences, suggesting __ transfer
bacteriophage; phage transfer
what are pathogenicity islands?
clusters of genes that have been acquired from external environment
pathogenicity islands increase ___ in organism
complement of genetic material
pathogenic E. coli have many ___ of virulence genes ___
clusters; scattered throughout
do virulence genes in E. coli completely replace normal E.coli genes?
no
what are 2 colonization factors?
pili and adhesion (possibly flagella)
are pili for adhesion present in typical E. coli?
no
what is the Locus of Enterocycle Effacement (LEE)?
pathogenicity island associated with intestinal cell attachment and diarrheal disease
what are effector proteins?
bacterial proteins that are “injected” into host cells
what is the function of effector proteins?
specific functions to alter, hijack and subvert cellular activities
what is the causative agent in Cholera?
Vibrio cholerae
what is the danger of cholera?
massive dehydration and ion imbalance by diarrhea
the cholera toxin is of the ___ type
AB
the cholera toxin is ___ to bacteriophage DNA, which suggests__
physically linked; once associated with a bacteriophage
toxin co-regualted pilus
the pilus genes have the exact same positive regulator
the combined effect of pilus and cholera toxin leads to
replication and massive host diarrhea
pathogenic E. coli inserts its own __ for cell attachment
receptor
virulence genes are often associated with pathogenesis by encoding __, ___ factors and new methods to inject ___
toxins, secreted; proteins
colonization factors mediate attachment to ___ and ___
host cell membrane; specific proteins
the LEE is a ____ nucleotide PAI flanked by ___ sequences
40 000; phage
the LEE is likely transferred as a __-
single unit
the LEE pathogenicity island has a __ system and regulators to control the ___ in the PAI
secretion; genes
example of function of effector proteins
actin trafficking
the cholera toxin sheds copious amount of ___ in the stool of hosts
new bacteria
