Exam 3 Flashcards
1
Q
4 ways cells defend against HGT
A
- toxin-antitoxin system
- restriction/modification system
- CRISPR system
- secretion systems
2
Q
explain toxin-antitoxin system
A
plasmid encodes a toxin and an antitoxin
daughters that lose the plasmid die; toxin is stable, antitoxin decomposes
daughters that retain the plasmid persist
net result is maintanence of plasmid in pop
3
Q
system for degrading incoming DNA
A
restriction/modification system
4
Q
EcoRI
A
restriction/modification system
restriction enzyme
cuts DNA at GAATTC
cuts DNA into 4000 bp segments
5
Q
bacteria protect their own DNA from EcoRI by…
A
using methylase to methylate adenines on GAATTC
6
Q
CRISPR abbreviation
A
clustered regularly interspaced short palindromic repeats
7
Q
Cas1
Cas2
A
CRISPR
bind viral DNA at protospacer adjacent motifs (PAMs)
8
Q
endonuclease
A
CRISPR
cuts out segment of DNA
9
Q
CRISPR regions
A
memory bank of previous phage infection DNA
10
Q
Cas9
A
CRISPR
surveillance protein
carries crRNA to corresponding region of virus in the case of a secondary infection
11
Q
Cas endonuclease
A
CRISPR
degrades tagged DNA of virus in secondary infection
12
Q
uses T4SS with a toxin on the tip that harms a DNA donor, preventing conjugation
A
Pseudomonas
13
Q
discovered first PAIs (2)
A
1921, Frobisher and Brown
1951, Freeman
14
Q
hly
A
alpha hemolysin
E. coli
15
Q
stx
A
Shiga toxins
16
Q
SP1-1
A
*Salmonella
*
Type III secretion proteins
PAI example
17
Q
supergenome/pangenome
A
all cells in a population that an organism can share PAIs with
18
Q
superbugs
A
combination of PAI transfer and antibiotic resistance transfer
19
Q
1979 belmont report (3)
A
respect for persons, informed consent
beneficence
justice
20
Q
animal models & pathogens:
mice
ferrets
guinea pigs
armadillos
chinchillas
zebra fish
nematodes
A
mice: S. enterica Typhimurium
ferrets: H. pylori
guinea pigs:M. tuberculosis
armadillos: M. leprae
chinchillas: H. influenzae, S. pneumoniae
zebra fish: necrotizing Streptococcus, Enterococcus
nematodes: P. aeruginosa
21
Q
ideal animal model (4)
A
sx and distribution match human
acquire disease in same way
low expense
history of usefulness
22
Q
nude mice
A
t cell deficient
23
Q
neutropenic mice
A
no neutrophils
24
Q
SCID mice
A
lack T and B cells
25
knock out mice
genetic deficiency
influence of missing gene studied
26
knock in mice
human gene inserted
27
Lewis B antigen
RBC sugar
in mice, show binding of *H. pylori*
28
gnobiotic animals
germ-free
29
gnobiotics lack...
normal gut immune system
30
naive animals
free of a pathogen of interest
31
CFU
one cell, 2 diplococci, 4 tetrads, etc
32
dose measured as...
CFUs
33
survival curve
fraction of surviving animals as a function of time
34
luxABDE
luminescence gene used in biophotonic imaging
*S. pneumoniae*
35
LD50
lethal dose 50
number of bacteria detected when 50% of animals are moribund
36
ID50
infectious dose 50
number of bacteria that will cause disease in the animal
37
ID50 graph
percentage of animals infected as a function of log(number of bacteria/animal)
38
competitive index =
39
CI = 1...
CI < 1...
CI > 1...
CI = 1; mutant is no different; gene not a virulence factor
CI < 1; mutant not as competitive as wild type
CI > 1; mutant is more virulent
40
direct comparison between wild type and mutant pathogens
competitive index
41
requirements to use CI
must be able to tell strains of bacteria apart
no trans effects
42
used to visualize tissue cultures
inverted microscope
43
limitaitons of tissue cultures
stop growing after a few generations
cells are nonpolarized
44
puromycin selection/PAT
transduction of viral proteins used to interrupt cell cycle in tissue culture
45
tissue cultures with bacteria are used to study...
invasion
46
used to study intracellular pathogen invasion
plaque assay
47
antibiotic used for plaque assay
gentamicin
48
explain plaque assay
pathogens allowed to attach and invade
free swimming bacteria are drained away
molten gentamicin agar is added to top cell layer, preventing extracellular transmission
plaques of intracellular bacteria measured
49
invasion frequency =
CFUs after gentamicin/total CFUs
50
actin tails with fluorescent labelling
green
51
chemicals used for fluorescent labelling
ethidium bromide/DNA
phalloidin/actin
anitbody/epitope (gold standard)
52
organ culture models
source
limitation
biopsies, circumcisions, cosmetic procedures
deteriorate in hours
53
batch culture stages of growth (5)
inoculation
lag phase
trophophase (exponential)
idiophase (stationary)
death phase
54
happens in lag phase
ribosome synthesis
55
happens in exponential phase
primary metabolism
56
happens in stationary phase
secondary metabolism
weird things
antibiotic resistance, pigments, HGT
57
MSCRAMM
microbial surface components recognizing adhesive matrix molecules
attachment mechanism
58
happens in death phase
endogenous respiration (cannibals)
59
infection stages of growth
exposure
attachment
colonization
persistence
spread
60
mode of life in environment pre-infection
stationary/poststationary
lack of nutrients, no adhesion sites, noxious substances, dryness, heat, light
61
bacteria inactive states
endospores
elementary bodies
myxospores
ultra-micro
62
safe havens for bacteria
reservoirs
63
biofilm begins with...
adhesion through glycocalyx and fimbriae
64
how does biofilm spread
planktonic bacteria
65
biofilms protect against...
antibiotics
phagocytosis
66
favorite biofilm locations for *P. aeruginosa*
problem for who?
mucosal surfaces, resp tract
CF patients with thick mucus
burn wound victims
67
poses similar problem to *P. aeruginosa*
*Burkholderia cepacia*
68
biofilm on teeth
organism
substance
*Streptococcus*
sucrose dextran glycocalyx
69
biofilm that is starved leads to...
fruiting body
spores
germination
70
recognizes flagellin
type of antigen
TLR5
H antigen
71
energy for flagella
proton gradient
72
shift between 2 versions of flagellin
*Salmonella*
73
peritrichous flagella allows...
ex)
swarming, moving over surfaces
*Proteus*
74
has dual systems of flagella used at different times
*Vibrio parahaemolyticus*
75
flagella in the periplasm constrained at both ends, allowing spirochete movement
endoflagella
76
monotrichous
lophotrichous
amphitrichous
peritrichous
one
many at one end
one on each end
all over
77
mucinase
degrades mucin
78
sIgA proteases
ruin IgA traps
79
allows *H. pylori* to penetrate mucin layer of stomach
helical shape, flagella
80
factor H
recruitment in capsule leads to complement degradation
81
organism that has many ways to "look like host"
*S. aureus*
82
"look like the host" factors (6)
sialic acids
hyaluronic acids
fibronectin-binding protein
collagen-binding protein
clumping factor (binds fibrinogen)
coagulase (precipitates fibrin)
83
protein A
binds Fc, deflecting antibody away
84
protections against defensins (3)
capsules
LPS (neg charge binds pos charged defensins)
peptidases (defensin-resistanct bac)
85
has proteins to break down host iron-binding molecules
*S. aureus*
86
2 classes of siderophores
catechol/enterobacin
hydroxamate/anguibactin
87
------- chemistry used by siderophores
coordination
88
cheaters for iron acquisition
don't make their own siderophores, but have uptake proteins for others'
89
GP iron carriers besides siderophores
staphyloferrins A & B
heme
90
GP system allowing siderophores inside
FhuBG
91
GN system allowing siderophores inside
ABC system
92
uses iron abstinence
substitute?
*Borrelia*
manganese
93
proteins in pili
pilin
94
on pili tip
adhesin
95
pili ligands
highly --------------
how can they be deduced?
usually glycoproteins/lipids
conserved
competition assay - if mannose is critical, pili bind to mannose instead of cells
96
tropism
specificity of binding determines which tissues will be infected
97
GPs with pili (6)
*S. salivarius
S. gordonii
S. oralis
S. mutans
Corynybacterium
Actinomycies*
98
type 1 pili
hemagglutination?
mannose?
genes?
yes
sensitive
*fim, pap, pil*
99
type 2 pili
hemagglutination?
gene?
binds to?
unique?
no
*cbIA*
mucin, epithelials, lung cells
binding motif is all along length
100
type of pili in Burk biofilms
type 2
101
type 3 pili
mannose?
organisms?
resistant
*E. coli, Klebsiella, Salmonella*
102
contribute to biofilms on catheters
type 3 pili
103
potential target of pilicides
type. 3pili
104
type 4 pili
arrangement?
assembly?
organisms?
unique?
bundles, polar
T2SS
GNs (*Neisseria, Pasteurella, Dichelobacter, Moraxella, Aggregatibacter, Pseudomonas*)
involved in DNA uptake, *Haemophilus*
105
pili that give motility
type 4
106
type 5 pili
assembly?
mannose?
organisms?
external
sensitive
*E coli*
107
system used to assemble type 1 pili
chaperone-usher system
108
SecAB
chaperone-usher
carries unfolded polypeptides across membrane
109
FimC/PapD
chaperone usher
fold and protect proteins
110
FimD/PapC
chaperone usher
usher proteins - seat subunits
111
FimA
chaperone usher
main pilus protein, makes body
112
PapH
chaperone usher
termination protein
113
SecYEG
curli
carries polypeptides across membrane
114
CsgC
curli
chaperone - protects proteins
115
CsgE
curli
processes proteins from CsgC
116
CsgG/CsgF
curli
allows subunits to cross outer membrane
117
CsgA/CsgB
shape
curli
main body proteins
folding beta sheet nature
118
CsgD
curli
transcriptional activator, turns on BAC
119
sortase
GP external assembly
anchor molecule, carries pili subunits to membrane
120
GP external assembly orientation of pilus proteins
N' at tip
121
in GPs, pilus is anchored to...
peptidoglycan
122
G-- have nonfimbrial proteins
GPs
123
nonfimbrial proteins attach to...
protiens (fibronectin, collagen, fibrinogen, vitronectin, laminin, bone slaloprotein, elastin, thrombspondin)
124
M protein
*S. pyogenes*
attaches to fibronectin in larynx
125
afimbrial adhesins bind...
integins. and cadherins between epithelial cells
126
allows host and afimbrial adhesins to attach
pathogen
highly conserved RGD sequences
*Yersinia*
127
InlA
InlB
*Listeria* internalins
mediate invasion
A binds E-caherin, B binds HGF-SF/C1q receptor
128
serum resistant
complement in blood fails to degrade bacteria
129
methods for complement evasion
capsules
LPS mods
130
capules to complement
Prevent alternative C3 convertase (C3bBb) from forming by either reducing attachment factor B or recruiting factor H, which destroys C3b (along with factor I)
prevents classical convertase C4bC2a from forming because it prevents diffusion of IgG (necessary for classical convertase)
131
capsules with hyaluronic acid
*S. pyogenes*
132
capsules with sialic acid
*N. meningitidis*
133
O-LPS mod allowing. itto evade MBL pathway
sialic acid instead of mannose
134
O-LPS mod that reduces killing by MAC
super long
135
when is baby vulnerable to meningitis
after 5 months, before 12 months
136
vaxx for college students against meningitis
MCV4
137
threat of meningitis
lipid A
inflammation in meninges
138
invasin/internalin action
promote rearrangement of actin filaments
A pocket forms, and bacteria can be taken into host cell, allowing it to evade the immune system
139
invasin first demonstrated in...
*Yersinia pseudotuberculosis*
140
SOD pathogen
*S. enterica* Typhimurium
141
flavohemoglobin
defends nitric oxide attack
*E. coli*
142
Mip
*Legionella* invasin
causes coiling phagocytosis
RER around vacuole prevents fusion
143
ruffles on surface via actin rearrangement
*Salmonella enterica*
no phagolysosomal fusion
144
*M. tuberculosis* uses what ligand to enter cell
C3 receptor
145
TACO
*M. tuberculosis*
surface of phagosome
prevents fusion
146
interleukin suppressed by *M tuberculosis*
IL-12
Th1 mediated killing
147
LLO
*Listeria, hly* gene
listeriolysin
pores in phagosome membrane
functions at 5.5 pH
148
SLO
*S. pyogenes* streptolysin
149
PLO
*S. pneumoniae*
pneumolysin
150
PFO
*Clostridium perfringens*
perfringolysin
151
cell to cell movement organisms (3)
*Listeria, Shigella flexneri, Rickettsia rickettsii*
152
ActA
recruits actin, pushing the bacterium forward as they are inserted
153
free themselves from netosis
DNAse pos
154
spreading factors
collagenase
elastase
hyaluronidase
155
streptokinase
*S. pyogenes*
dissolves fibrin clots by activating plasminogen to plasmin
this allows the bacteria to spread, even into the bloodstream
