Them Bacteriaz Flashcards
(93 cards)
1
Q
bacteria are
A
single-cell organisms and prokaryotes
2
Q
amount of chromosomes in bacteria
A
1 chromosome – can have more than one copy
3
Q
size of bacteria
A
0.2-2 microns in diameter
4
Q
two shapes of bacteria
A
cocci or bacili
5
Q
cocci pair examples
A
pneumococci, meningococci, gonococci
6
Q
chain cocci examples
A
streptococci
7
Q
“grape like clusters”
A
staphylococcus
8
Q
bacilli
A
rod shape of bacteria that varies in length
9
Q
types of bacilli (rods)
A
square/rounded ends, short and rounded, tapered ends (fusiform), curved rods
10
Q
hook shapes
A
vibros
11
Q
prokaryotic nucleus
A
no nuclear membrane
12
Q
prokaryotic division
A
no mitotic division
13
Q
prokaryotic DNA
A
not associated with histones
14
Q
prokaryotic organelles
A
no membrane-bound
15
Q
prokaryotic ribsome size
A
70s
16
Q
eukaryotic ribosome size
A
80s
17
Q
types of storage granules
A
glycogen, PBHB, elemental sulfur, polymerized metaphosphate
18
Q
plasmids
A
extrachromosonal DNA elements
19
Q
bacteria that produce spores
A
bacillus and clostridium
20
Q
bacillis
A
gram positive, rod shaped, obligate aerobe
21
Q
clostridium
A
gram positive, rod shapes, obligate anaerobe
22
Q
spores do not
A
undergo division, only germination (under favorable conditions will germinate and produce a single vegetative cell)
23
Q
prokaryotic cell membrane
A
no cholesterol or sterols (EXCEPT mycoplamas)
24
Q
mycoplasmas
A
cause primary atypical pneumonia
25
cationic dye added: bacteria stain
purple
26
add iodine
bacteria stain more purple
27
add ethanol/acetone
decolorization step, gram negative become decoloarized
28
counterstain
positive -> purple, negative -> pink
29
the more cross-linking of peptioglycan...
the more pigmentation
30
peptioglycan
polysaccharide with peptide cross links responsible for the structural rigidity of the cell, "sac like macromolecule" surrounding the entire cell
31
basic units of peptioglycan
NAG, NAA
32
peptioglycan sygar moeities
beta-1,4 linkage <-- cleaved by lysozyme (saliva, tears, white blood cells)
33
peptioglycan crosslinking
via a pentaglycine bridge which is inhibited by penicillin
34
teichoic acids
found in gram positive organisms, repeating units of ribitol phosphate or glycerol phosphate joined through phosphodiester linkages, constitute major surface antigens of certain gram positive bacteria
35
wall teichoic acids
are attached to peptioglycan
36
membrane teichoic acids
attached to lipids embedded in the membrane
37
gram negative
outer membrane lipid bilayer composed of phospholipid and protein.
38
major antigenic determinants of gram negative bacteria
O-antigens (outer part of outer membrane that is anchored to the lipopolysaccharide)
39
endotoxin: gram negative
very important contributing factor to the severity of disease, lipopolysaccharide is the endotoxin of gram negative bacteria
40
space between the outer membrane and the inner membrane
perplasmic space and location for a number of hydrolytic enzymes or lysosomal-like enzymes present in gram negatives
41
lipid A
responsible for endotoxic activity of gram negative bacteria - virtually constant among gram negative organisms
42
presence of an O antigen
determines if the bacteria is "smooth" (as does a capsule), also important for serological typing "serotyping"
43
protoplasts
gram positive, mycoplasma, "bacterial persisters"
44
spheroplasts
gram negative, do no completely shed peptioglycan layer due to retention of the outer membrane
45
capsules
smooth, prevents pathogenic bacteria from phagocytosis, most are polysaccharides, K antigens (antigenic determinants)
46
bacillus anthracis capsule
made up of polyglutamic acid
47
flagella
not virulence factors, 3-12 microns, stain to see, locomotion, H antigens (serotype), flagellins, differences in aa primary structure
48
peritrichous
flagella all around the bacteria (vs. polar flagella on opposite sides)
49
pili
short hair like projections, protein in character, thinner and shorter than flagella, thought to be involved in adhesion,
50
F-pilus
special pilus used for conjugation (receptor for specific F phages)
51
definition of endotoxin
LPS component of gram negative bacterial outer membranes that is released at cell destruction or during normal growth cycles
52
definition of exotoxin
substance elaborated into the host tissues by a microorganism that causes damage to structure or function of affected target cells
53
definition of fibronectin
host cell surface associated glycoprotein that mediates nonspecific adherence of some bacteria (staph)
54
definition of pyogenic
stimulates the recruitment of polymorphonuclear white cells
55
definition of pathogenic bacteria
cause disease in the host...host inflammatory reponse
56
opportunistic bacteria
cause disease in immunosupressed, not healthy, people
57
barriers to entry
skin, ciliated epithelium, antibacterial secretions, mucin layer
58
pili and fimbriae
rod shaped protein structures, ordered array of single subunits, with tip structure that attached to host (usually carb residues)
59
adherence of bacteria occurs via:
pilli/fimbriae, afimbrial adhesins, biofilms
60
afimbrial adhesions
bacterial cell surface proteins that do not form pili, mediate binding to host (usually host proteins)
61
biofilms
ordered 3-D structures composed of pillars of bacteria surrounded by water channels, formed by bounding bacteria within polysaccharide slime, refractory to disinfectants and antibiotics
62
biofilms can...
be the source of aerosolized bacteria, can form on body surfaces/plastic tubing/plastic implants
63
iron
is essential to bacterial growth and is not found in its free form in humans (bound to transferrin/lactoferrin/ferritin/hemoglobin)
64
bacteria sequester
iron
65
bacterial sequester iron via
siderophores (low MW secreted compounds), binding to host proteins to sequester iron, toxins to kill host cells, iron abstinence
66
lyme disease causing bacteria
do not require iron for growth, use Mn as an alternate cofactor in non-dispensable enzymes
67
dealing with uptake via phagocytosis
1) prevent phagosome-lysosome fusion 2) degrade/form pores in lysosome membrane
68
phagocytosed bacteria can be killed by what host defense(s)?
NK cells, cytotoxic T-cell response
69
adaptation to live in a phagolysosome
producing enzymes that detoxify reactive oxygen species/prevent oxidative burst
70
phagocytes
immune cells with lysosomes
71
(Shigella or listeria) & actin
bacteria that grow in cytoplasm induce actin condensation to move to neighboring cells
72
shigella enters through
M cells
73
pathogenicity islands
cluster on bacterial chromosome of genes encoding virulence factors
74
hallmarks of pathogenicity islands
different CG content, near/within tRNA genes, encode virulence factors, acquired via horizontal gene transfer
75
virulence factor exams
adhesins, specialized secretory systems, toxins
76
horizontal gene transfer occurs via
transposons, bacteriophages
77
Type I Secretory System
one channel, span inner&outer membranes, no periplasm intermediates, one protein apparatus (usually); hemolysin
78
Type II Secretory System
general, inner membrane steps, periplastic intermediate, signal sequence (termini a), secrete virulence and non-virulent factors, cholera toxins
79
Type III Secretory System
one channel, span inner&outer membranes, several proteins, made to secrete virulence factors; "needle type"
80
"needle type" secretory system
Type III, injects virulence factors straight from bacteria to eukaryotic cytoplasm. result: changes cell signal transduction pathway causes inflammation, opening of tight junctions, electrolyte secretions, alteration on cytoskeleton; E.coli
81
Type IV Secretory System
span inner&outer membrane, several proteins, transfer bacterial DNA/effector proteins; "pili-type" structure; H. pylori
82
capsules
usually polysaccharides & occasionally proteins, protect against complement activation and phagocytes, some made with sialic acid or hyaluronic acid to mimic host cells
83
LPS
complement target in gram - bacteria,
84
LPS modification to change complement interaction
attach sialic acid to O-antigen (prevents C3 convertase formation), change LPS O-antigen length (prevents MAC mediated death)
85
exotoxins vs. endotoxin
exo found in gram - and +, endo in gram - only
86
exotoxin nomenclature is based on:
target, producing bacteria, activity, designated letter
87
the majority of bacterial toxins are encoded on
mobile genetic elements (bacteriophages) and plasmids (e.g. heat stable and heat labile toxins
88
type I toxins
bind to cell, not translocated inside; superantigens
89
superantigens
type I toxin, bind to MHC class II (macrophages), bind to T cell receptors (that bind to MHC), 1:5 T cells are stimulated by the binding of superantigens --> excessive cytokine (IL-2) release ---> toxic shock (strep)
90
type II toxins
destroy eukaryotic membrane integrity; protein that forms membrane channels or an enzymes (phospholipase) that remove the polar head group of membrane phospholipids (s. aureus alpha)
91
type III toxins
A(=1) -B(>=1) toxins, A subunit has enzymatic activity, B subunit binds to host cell receptor (usually carb based), simple/complex toxins enter the cell
92
A-B subunits
type III toxins, usually separated by proteolytic cleavage but remain connected; A subunit is translocated into the cytoplasm, the B subunit determines toxin specificity
93
A subunit
removes ADP-ribosyl group from NAD, covalent attachment to host protein ---> creates a variety of pathogenic downstream effects
