virulence factors and infection quiz Flashcards
obligatory steps for infectious “bugs”
- entry or attachment to the body
- evasion of the immune system
- shedding from/exiting the host
- causing damage or disease-associated processes in the host*
bacterial parts that allow obligatory steps for infectious bugs are called
virulence factors
many bacteria enter the body through
cuts in the skin
for bacteria that do not enter through cuts in the skin
they need to pass through a mucus layer
two ways bacteria can pass through a mucus layer (Entry to the Body)
sigA proteases
mucinases
the protection of mucus membranes across the body s mediated by
antibody secretory IgA (sigA)
sigA is found
in extremely high concentrations in the airway and GI tract
why would bacteria release sigA proteases
destroys human IgA antibodies
destruction of human IgA antibodies causes what
neutralizes host defense in those areas, allows bacteria to live there
mucinases
enzymes that degrade the proteins inside mucus
mucinases allow what for bacteria
allows them to settle on or under mucus membranes
many bacteria have what for attachment to body
pilli
fimbriae
singular of pilli
pilus
singular of fimbriae
fimbria
fimbria and pilus can be used interchangeably
yes, for some pilus is only for conjugation
pili and fimbriae are what on most bacteria
peritrichous
peritrichous
projections all over its surface
pili act as
feelers for bacteria
when pili feel a desired surface
shorten and pull the bacterium in
pili are more prevalent in what
gram-negative bacteria
adhesive proteins that stick to other proteins
adhesins
membranes of many microbes have
special type of adhesins
what are the special adhesins that the membranes of many microbes have
MSCRAMMs
MSCRAMMs
Microbial Surface Components Recognizing Adhesive Matrix Molecules
roles of MSCRAMMs
target host cells and allow for tight connections between them and bacteria
human cells are coated in what proteins for MSCRAMMS to targe
- transport
- receptor
- adhesion
- glycoproteins
role of transport proteins
move things in or out of cells
characteristics of transport proteins
- opened and closed
- very selective
role of receptor proteins
help the inside and outside of the cell communicate
which proteins usually work together in human cells
transport and receptor
example of adhesion proteins in human cells
integrins
role of adhesion proteins
help stick cells in place
characteristics of adhesion proteins
- grab onto collagen in the extracellular space
- grab onto other integrins on other cells to hold hands
role of glycoproteins
stick carbon chains into the extracellular space, forming a glycocalyx around a cell (CELL ID)
different MSCRAMMs target
different types of host membrane proteins
bacteria also have their own
OWN GLYCOCALYX
integrin proteins connect cell to
to extracellular collagen
different bacteria attack the body by
colonizing different surfaces
bacteria choosing to live on outer epithelial layer
try to outcompete normal flora, but it is hard
bacteria choosing to live into deeper extracellular space
burrow way through epithelial layer to get there
bactiera choosing to live inside …
inside the host cell
bacteria deliberately eaten by phagocyte
so they can reproduce inside a phagosome or phagolysosome.
after reproducing inside a phagocyte or phagolysosome a bacteria can
pop out or keep living there
depending on how deep into skin a pathogen gets
the manifestation of infection varies
where does Y. pestis grow
inside white blood cells
some bacteria come with a very THICK
thick glycocalyx.. called slime layer
inside the slime layer there is
thinner layer of proetins called the S layer
proteins of S layer
highly variable between species
the slime layer and S layer provide the bacteria with
partial defense from phagocytes and covers some of the bacteria’s PAMPs
example of bacteria w/ slime layer
streptococcus pneumoniae
what caues gonorrhoea
Neisseria gonorrhoeae
pili are what in Neisseria gonorrhoeae
the immunodominant structure
pili being the immunodominant structure in Neisseria gonorrhoeae means
predominantly N. gonorrhoeae’s pili that are recognized by antibodies.
different strands of N. gonnorhoeae
different structures of pilli; over1 million different pilus structures
N. gonnorhoeae having so many different plius structures causes
memory B cells to be useless against it, makes people prone to reinfection
the N. gonorrhoeae phenomenon is a tactic many other bacteria and virus use called
antigenic variation
bacteria that live inside a host cell
need to find a way to escape
some ways of exiting the host leave the host cell intact,
some do not
1 st way of exiting the host
-settle inside vacuole and drive vacuole out
2nd way of exiting the host
hijack cellular machine designed to secrete proteins through exocytosis
3rd way of exiting the host
pop a big hole in the cell’s membrane, causing it to die
bacteria often cause collateral
damage to surrounding tissues
humans cells towards____ have ____
towards mucosal linings have hyaluronic acid in their membrane as a mortar
hyaluronic acid is very
large molecule (molecular weight in millions), largely unknown functions
hyaluronic acid functions
largely unknown
some pathogenic bacteria secrete what to break down hyaluronic acid
hyaluronidase
why do bacteria secrete hyaluronidase
to break down hyaluronic acid to use its carbons for own processes
result of bacteria using hyaluronidase to break down hyaluronic acid
damage to cell membranes, cellular death
iron is
essential nutrient for bacteria, difficult to come across
iron is necessary to build
peroxidases and operate an electron transport chain
electron transport chains are
important for ATP production in bacteria
easiest place for bacterial colony to find iron in the human body
hemoglobin found in blood
because iron is found in the blood, bacteria secrete
hemolytic enzymes called hemolysins
why do bacteria secrete hemolysins
to steal the body’s iron from hemoglobin
bacteria can also cause damage through
toxins
two types of toxins that bacteria have
endotoxins, exotoxins
endotoxin
refers to LPS in the membrane of gram-negative bacteria
LPS
lipopolysaccharides
why is LPS dangerous to humans - reason 1
-cause vast increase in secretion of cytokines cause inflammation and swelling
why is LPS dangerous to humans - reason 2
-leads to release of histamines…. causing vasodilation
why is LPS dangerous to humans - reason 3
-leads to activation of coagulation cascade
coagulation cascade
cascade that leads to the formation of thrombi (blood clots
LPS puts people at risk for
septic shock, heart attack, and stroke.
exotoxins
diverse class of toxins, all proteins created by a bacterium
1st thing that exotoxins can do
are secreted and act on surrounding issue
examples of exotoxins that act on surrounding tissue
hyaluronidase and hemolysin
2nd thing that exotoxins can do
enter cells and ribosylate host proteins
how does an exotoxin ribosylate a host protein
add ADP+ ribose… turns proteins on or off… often off
3rd thing that exotoxins can do
break turn certain proteins such as sigA
4th thing that exotoxins can do
other mechanisms
in the case of exotoxins, symptoms..
not cause y bacterium themselves but by the exotoxins secreted
