Diversity/ Charateristics Of Bacteria 2-4

Front 1

What are bacteria?

Back 1

prokaryotes with ester linked membrane lipids, and peptidoglycan cell wall

Front 2

Bacterial Shapes (morphology)

Back 2

Sperical (cocci)

Rods (bacilli)

filaments

curved rods (vibrios)

spirals (spiralla and spirochaetes)

mycelia (branched filaments)

Front 3

Strictly aerobic?

Back 3

NEED o2

Front 4

microaerophilic?

Back 4

need O2 at low levels

Front 5

facultatively anaerobic?

Back 5

will use O2 if present

Front 6

aerotolerant?

Back 6

can live in aerobic but do not use O2

Front 7

strictly anaerobic?

Back 7

killed by o2

Front 8

Gram staining technique?

Back 8

stain with crystal violet, fix with I2, destain with alcohol, counter stain with fuschin

purple- gram pos (retain dye)

pink- gram neg (didn't retain dye and stained by fuschin)

Front 9

Genus Streptococcus info?.

Back 9

gram positive

cocci in chains/ pairs

facultatively anaerobic

found on human membranes

Front 10

Oral Streptococcus?

Back 10

S. mutans and S. salivarius

colonise teeth, convert sucrose to dextron capsule

use dextrin to adhere to teeth surface

there they ferment sugars to lactic acid

-> tooth decay

Front 11

Pneumonia/ Meningitis causing Strep?.

Back 11

S. pneumoniae

usually cocci pairs

with polysaccharide capsule as main virulence factor

alpha haemolytic

Front 12

Genus Staphylococcus info?.

Back 12

gram positive

facultatively anaerobic

cocci in clusters

skin and mucosal membranes

Front 13

Staphylococcus aureus?

Back 13

Invades wounds=> 2ndry pneumonia, food poisoning, scalded skin syndrome, TSS

develops resistance very well

Front 14

VRSA and MRSA?

Back 14

vancomycin resistant S. aureus

methicillin resistant S. aureus

Front 15

Gram negative bact. eg?

Back 15

Salmonella typhi - typhoid

Legionella pneumophila -legionnaires

Front 16

Acid fast bacteria?

Back 16

Mycobacterium- aerobic rods with waxy lipid coating

large amount of mycolic acids (lipid) in cell wall that resist gram staining,

identify with Ziehl Neelson- red with blue back ground

Front 17

Example of acid fast bacteria?

Back 17

Mycobacterium bovis, M. tuberculosis

M. leprae

Front 18

Enderospores?

Back 18

dormant non reproductive structure produced by some bacteria

survive 1000s years, resistant to heat, production triggered by adverse conditions

Front 19

Formation of enderospores?

Back 19

Bacteria undergoes asymmetrical cell division

Spore produces Ca- dipicolinate (=> dehydration and inc. heat resistance) and small sol. proteins to protect DNA, ribosomes etc.

"mother" secretes protein coat to protect spore

then lyses and releases them

Front 20

Examples of spore forming?

Back 20

Clostridium botulinum, C. tetani, C. perfringens, C. difficile, Bacillius antracis

Front 21

Bacterial cell wall?

Back 21

Composed of peptidoglycan

polysacch, chains with peptide crosslinks

Front 22

Peptidoglycan structure?

Back 22

Alternating N-acetyl glucosamine and N-acetyl- muramic

gram pos. = 20-25 layers

gram neg.= 1-3 layers

Nam residue= site for Beta lactams (a type of anti bio) binding

Front 23

Arrangement of PDG in gram negative?

Back 23

the PDG polysacch chains wrapped around circ. of cell with peptide links parallel to axis

Front 24

Arrangement of PDG in gram positive?

Back 24

polysacch. chain wound into cable and wrapped around cell

Front 25

Lipopolysaccharide?

Back 25

outter part of outer membrane

therefore only on gram negative

Lipid A- 4/6 3 hydroxy fatty acids attached to a

dimer of glucose amine phosphate (on membrane side)

Core polysaccharide- fairly conserved linker

8,7 and 6 carbon sugar

O-polysaccharide- 4-6 sugars repeated 10/20

times. Hydrophilic- repels phobic mol

Front 26

Which specificity and toxicity of LPS?

Back 26

O- polysacch. varies and is highly strain specific

(somatic antigen)

Lipid A- causes fever (endotoxin)

Front 27

Good antibiotics for LPS (neg. bac)?

Back 27

Polymixins- disrupt LPS

Front 28

Bacterial capsules? .

Back 28

amorphouse polysaccharide slime secreted by bacteria to surrounding cells, forming tight matrix

presence and composition is strain specific

roles- prevent desiccation, inhibit phagocytosis ( e.g. streptococcus pneumoniae), attachment to surfaces (e.g. oral streptococci)

Front 29

Bacterial flagella?

Back 29

used to move through liquids

particularly common

arrangement and number is strain specific

20nm in diameter

recognised by immune system

Front 30

Flagella Structure?

Back 30

Hollow filaments made of flagellin

attached via hook to membranes

L- ring attached to outer memo (neg. only)

P- ring in PDG layer

MS ring in cell membrane- with motor and switch proteins

Front 31

How does flagella cause movement?

Back 31

generates thrust by rotating 200-1000 rpm

M protein produces energy- ATP

switch protein controls direction of rotation

Front 32

Bacterial Pili and Fimbriae

Back 32

protein spikes used for attachment- shorter than flagella

lots of fimbriae, few pili

pili- DNA transfer in conjugation

Front 33

Type 1 Fimbriae?

Back 33

Used by E.coli to adhere to urethra-> UTI

Front 34

Bacterial Swarming?

Back 34

move in large groups along surface

use flagella- often multiple lateral formation

a.g. Bacillus

Front 35

Bacterial twitching?

Back 35

Retractable polar Type 4 pili

e.g. Pseudomonas, pili attached to substrate or other bacteria, and then contracts to pull forward

Front 36

Bacterial gliding?>

Back 36

occurs in filamentous bacteria which don't swim

e.g. Myxococcus

Front 37

What do bacterial walls let through?

Back 37

Cytoplasmic membrane- perm barrier

PDG- allows small molecules

Outter membrane- repels H. phobic but allows small phillic through porins

Front 38

Bacterial passive transport across memb ?

Back 38

relies on conc. gradient

simple diffusion- small phobic mol. (gram pos)

facilitated diffusion- phillic mol. through channel/ carrier protein. e.g. E.coli GlpF transporter to transport glycerol

Front 39

Bacterial Active transport

Proton symport?

Back 39

Driven by transmembrane proton gradient, where 1 or more protons enters with substrate

e.g. E.coli lactose permease, LacY

Front 40

Bacterial active transport

ABC proteins?

Back 40

ATP binding casette transporters

driven by ATP hydrolysis, assoc. with periplasmic substrate binding proteins

Front 41

Maltose transport in E.coli

Back 41

ABC

Maltose transporter (MalFG assoc. with MalK)

MalK hydrolyses ATP-> ADP and Pi

MalFGK transport maltose into cell which is assoc. with periplasmic binding protein MalE

Front 42

Active transport in Bact

Group translocation?

Back 42

substrate modified, generally phosphorylated, during transport

saves an ATP as 1st step of glycolysis requires phosphorylation anyway

Front 43

Glucose uptake in E.coli

Back 43

Group translocation

PEP-> pyruvate, phosphate passed along system via enzymes chain (2a,2b and 2c are specific to substrate)

end of chain stim. glucose to cross memb. and it phosphorylated to glucose-6-phosphate in the process

Front 44

Crossing the outer membrane?

Back 44

Gram negative only

Porins allow free diffusion of small phillic mol.

Some substances can be actively moved using energy derived from cyto. memo. proton gradient, energy passed to channel/ carrier on OM via TonB

Front 45

Outer membrane active transport example?

Back 45

On cytoplasmic membrane ExbBD gains energy by proton gradient

Passes energy through TonB to BtuB transporter

BtuB transport B12 across OM into periplasm

Front 46

Secreting small molecules from bacteria?

Back 46

e.g. antibiotics, siderophores etc.

Uses ABC transporter or proton antiporter

Front 47

Secretion of proteins from bacteria?

type 1

Back 47

each target has on ABC transporter

exported across CM and OM using membrane fusion protein and outer memb. protein

use energy from hydrolysing ATP

Front 48

Example of type 1?

Back 48

E.coli haemolysin secretion

HlyA recognised by region in C terminal of transporter protein,

ATP hydrolysed and energy used to transport HlyA by HlyD, HlyB and TolC transporters

Front 49

Secretion of proteins

Type 2

Back 49

Proteins to be exported from periplasm are recognised

Pore is formed from subunits of protein D

like a retractable type 4 pili, assembled like a piston and pushed protein out

for extracellular hydrolytic enzymes

Front 50

Secretion of proteins type 3?

Back 50

Injectisome

assoc. with extracellular needle complex to insert across membrane of host cells

Front 51

Type 3 secretion example?

Back 51

E.coli (enteropathogeniic strains)

use to inject translocated intimin receptor in to cell membrane, so can use their own intimin to bind to it

Front 52

Type 4 protein secretion?

Back 52

related to machinery used to export DNA: protein complexes during conjugation

Used by heliobacter pylori, Boretella pertussis

Front 53

General Secretion Pathway form bacteria?

Back 53

target identified by N terminal sequence on signal

chaperoned by SecB or signal recognition particle, fed through Pore SecYEG into periplasm (in unfolded state)

energy from SecATPase and proton channel SecDF

in periplasm Lep removes lead peptide and protein unfolds.