Bacterial Endospores L16

Question 1

what are endospores

Answer 1

dormant structures formed by bacterial cells in unfavourable environments

Question 2

where are endospores

Answer 2

only in gram positive genera

Question 3

where are endospores usually found

Answer 3

mostly in bacillus and clostridium

Question 4

where can endospores also be found that is not common

Answer 4

Can also be formed in less common genera of bacteria

Question 5

what are the gram negative bacteria (purple)

Answer 5

Escherichia coli
Salmonella typhimurium
Agrobacterium tumefaciens
Campylobacter jejuni

Question 6

what are the gram positive bacteria

Answer 6

Bacillus anthracis
Clostridium botulinum
Staphylococcus aureus
Listeria monocytogenes

Question 7

which of the gram positive bacteria that are spore forming

Answer 7

Bacillus anthracis

Clostridium botulinum

Question 8

who discovered spores

Answer 8

ferdinand cohn

Question 9

what did ferdinand cohn demonstrate

Answer 9

heat-resistant properties of endospores in Bacillus subtilis

showed the vegetative cells but not the endospores are killed in boiling water

Question 10

what did ferdinand cohns discovery lead to

Answer 10

development of the autoclave

Question 11

what do spore forming bacteria aid

Answer 11

identification process
Spore is always in the same place if same cell
restricted to small amount of bacteria – spore forming
Phenomenum in all of them is different

Question 12

how are endospores formed

Answer 12

intracellularly

Question 13

what does sporulation start with

Answer 13

asymmetric division of the mother cell

Question 14

where do spore layers develop

Answer 14

inside mother cell

Question 15

what happens in sporulation

Answer 15

released from mother cell / sporangium as free spores

Question 16

what happens in sporulation process

Answer 16

1.asymmetric cell division, spore septum begins to isolate newly replicated DNA and small portion of cytoplasm septum forms at one end of the cell – not cell in half
2. Plasma membrane starts to surround DNA cytoplasm and membrane isolated
End up with a small cell and a big cell – two separate compartments
3. Second engulfment of the spore by the remaining cell
Programmed cell death to form the sporangium
4. Makes peptidoglycan between the two membranes that have formed in the cell
5. DNA degrades, coat forms around peptidoglycan layer, further protection
6. Endospore released

Question 17

what are endospore composed of

Answer 17

central spore surrounded by various protective layers
exosporium
spore coat
cortex
core

Question 18

what is the exosporium

Answer 18

thin covering made of protein

Question 19

what is spore coat

Answer 19

highly cross-linked keratin and layers of spore specific proteins

Question 20

what is the cortex

Answer 20

loosely cross-linked peptidoglycan

Question 21

what is the core

Answer 21

condensed chromosome, packaging proteins and spore-specific compounds

Question 22

if there is severe dehydration what happens

Answer 22

no processes can occur

Question 23

what are bacterial endospores known for

Answer 23

most heat resistant living structures

Question 24

what are bacterial endospores resistant to

Answer 24

Pressure
Vaccum
Desiccation
Irradiation (UV, X- and γ- rays)
Antibiotics
Chemical disinfectants
Extremes of pH
Heat

Question 25

what are the reasons for spore stability

Answer 25

``` Proteinaceous Coat Calcium dipicolinate Specialized DNA-binding proteins Dehydration of the cortex DNA repair enzymes in the endospore ```

Question 26

what is the proteinaceous coat function in spore stability

Answer 26

resists lysozyme /degradative enzymes; impermeability of this layer protects spore from chemical inactivation

Question 27

what is the calcium dipicolinate function in spore stability

Answer 27

stabilises DNA

Question 28

what is specialised DNA-binding proteins function in spore stability

Answer 28

coats DNA and protects from heat, drying, chemicals, UV radiation

Question 29

what is dehydration of cortex function in spore stability

Answer 29

removes water from endospore interior and prevents diffusion

Question 30

what is the DNA repair enzymes in endospore function in spore stability

Answer 30

repair damaged DNA during germination

Question 31

what can spores used for

Answer 31

some spores contain spore associated toxins | clostridium botulinum causes botulism - for botox, causes paralysis of muscles

Question 32

what can spores cause in humans

Answer 32

Bacillus cereus & Clostridium perfringens cause food poisoning (GI tract)*

Question 33

what is bacillus thuringiensis protein specific for

Answer 33

Lepidoptera

Question 34

what must the conditions be for bacillus thuringiensis be to be solubilised

Answer 34

only solubilised under alkaline conditions (in gut of insect larvae) activated in alkali (insect gut pH is alkali)

Question 35

what is bacillus thuringiensis purified toxin known as

Answer 35

organic pesticide

Question 36

how can purified toxin be made

Answer 36

can purify the toxin then use that | Or can spray around bacillus thuringeiensis the organism that makes the toxin (natural so preferred)

Question 37

what is the downside of the natural method to produce purified toxin

Answer 37

closely related to bacillus cereus which will do that to us to harmful

Question 38

how can endospores enter the body

Answer 38

abrasions to skin orin lungs

Question 39

what happens when spores enter the body

Answer 39

favourable conditions allow the spores germinate and new vegetative cells start to grow

Question 40

what is a bacterial endospore

Answer 40

a neurotoxin

Question 41

what causes sporulation

Answer 41

Entry into the sporulation cycle can only occur at a specific point in the cell cycle Requires active cell division dont want togo into sporulation unless have to

Question 42

what things lead to sporulation

Answer 42

nutritional signals | population density

Question 43

how do nutritional signals lead to sporulation

Answer 43

Carbon, Nitrogen or Phosphorous starvation induce sporulation Rapidly metabolised carbon sources, (e.g. glucose) repress sporulation

Question 44

how does population density lead to sporulation

Answer 44

Sporulation not induced efficiently at a low population density At high density vegetative cells grown produce a substance necessary for efficient sporulation

Question 45

what do some endospores need before germination

Answer 45

activation

Question 46

how are most endospores activated

Answer 46

heat - required for optimum germination but amount of heat varies with spore type or chemical signal - some simple chemical act as signals

Question 47

what is a downside of sporulation

Answer 47

very energy costly - Cells don’t induce this unless appropriate environmental signals present

Question 48

what is an advantage of endospores

Answer 48

can persist for a long time in inert state

Question 49

what is a disadvantage of germination

Answer 49

not guaranteed - dependent on environmental signals