continuous up regulation of heat shock proteins in larvae but not adults of polar insect- Rinehart, Hayward

Question 1

What is the main species studied?

what is it know to be?

Answer 1

Belgica Antarctica

largest year round free living inhabitant in antarctic

Question 2

a) whats the ‘order’ of the midge?
b) what can it survive?
c) where is it found?
d) what does It feed on?
e) how long is its life cycle?
f) most of the time what is its form?

Answer 2

a) Diptera
b) extreme desiccation losing 70% of moisture and can survive extreme temps
c) Antarctic peninsula
d) dead plant material, algae, bacteria, microorganisms
e) 2 years
f) worm like larvae

Question 3

what is the summer air temp?

and subsurface temp?

Answer 3

5c

25c

Question 4

what were the 2 main things that were examined?

Answer 4

• ability of B.Antarctica to survive a rage of temps

- capacity of thermoregulation

Question 5

what is the instar phase?

Answer 5

when they are freeze tolerant

Question 6

briefly what was the method? (4 main steps)

Answer 6

• collect 4th instar and adults
• exposed them to moderate temp then more extreme heat stress
• measured survival
• cloned genes encoding 3 HSP and looked at expression in response to temp stress

Question 7

after how many hours did survival drop for larvae exposed to:
- 20c
- 25c
- 30c
what does this show about mortality?

Answer 7

• 72hrs
• 24hrs
• even sooner
  mortality increased at progressively high temp

Question 8

are adults or larvae more heat tolerant?

Answer 8

larvae are more heat tolerant

Question 9

at 15,20,25c for 2hr what was the larvae survival like?

at 30c?

Answer 9

all survived

survival drops

Question 10

for larvae if you go from 15c for 2hr then 30c for 3hr rather than remaining at 30c what is the survival like and what does it mean?

Answer 10

there is a lower survival rate

larvae can’t develop thermoprotection

Question 11

in adults if they are exposed to mild heat first and then higher what is their survival like?

Answer 11

increased survival and so can develop thermoprotection and up regulate HSP in response to heat stress

Question 12

at 4c is HSP expressed for adults or larvae?

Answer 12

only in larvae

Question 13

at 30c is HSP expressed for adults or larvae?

Answer 13

only in adults

Question 14

what does it result in by expressing HSP?

Answer 14

less protein aggregation

Question 15

whats the difference in larvae and adults for the regulation of HSP?

Answer 15

larvae: constitutively up regulate HSP and maintain high tolerance to temp stress (thermally stable habitat)
adults: HSP thermally active so low tolerance but it can be enhanced

Question 16

what kind of adults aren’t freeze tolerant?

Answer 16

wingless

Question 17

what do larvae in thermally buffered soil express/lack?

Answer 17

express HSP transcripts constantly and lack ability to generate thermoprotection

Question 18

what can HSP expression in larvae prevent?

Answer 18

can prevent irreversible protein aggregation due to environmental stress

Question 19

for how many days did the larvae survive for at 4c?

Answer 19

up to 16

Question 20

at LT50 (median lethal time) at 15c how many days did the larvae survive?

Answer 20

> 12 days

Question 21

on average how ling do adults live?

Answer 21

1-2 weeks

Question 22

did a 2hr exposure alone affect survival?

Answer 22

no

Question 23

what did HSP70 primers in PCR result in?

Answer 23

231bp-product

Question 24

what % identity is the hsp70 from B.antarctica to mosquitos A.Gambiae and C.pipiens?

Answer 24

84%

Question 25

for hsp70 what % similarity and what % +ve identity between B.antarctica and C.yoshimatsui?

Answer 25

98% similarity

100% +ve. identity

Question 26

for hsp70 what % similarity and what % +ve identity between B.antarctica and mosquitoes (Gambia and pipiens)?

Answer 26

97% similarity

100% +ve identity

Question 27

for the 710 bp product for hsp90 what was the % identity of B.antarctica and:

• drosophilia
• A. albimanus
• C. capitata

Answer 27

• 70%
• 77%
• 75%

Question 28

what did hybridisation reveal about the expression of all hsp transcripts for larvae and adults at 4c?

Answer 28

expressed at high levels in larvae

little/no expression in adults

Question 29

did high or low temp increase hsp transcript abundance in larvae?

Answer 29

neither

Question 30

why may there have been a diminishment of signal for 2hr exposure at 30/35c?

Answer 30

death of insect

Question 31

when is there high expression in the larvae?

Answer 31

when actively feeding or growing

Question 32

what are the 3 hsp?

Answer 32

hsp70, hsp90, small hsp

Question 33

what did mild temp shocks fail to do in the larvae and what does this mean?

Answer 33

failed to boost hsp expression and generate tolerance because hsp defence system is already maximally expressed in the larvae

Question 34

what is a criticism of the study?

Answer 34

too few species examined to conclude it as being a common adaptation in antarctic organisms

Question 35

when may hsp be unregulated?

Answer 35

when overwintering diapause of temperate zone insects

Question 36

whats the difference between adults and larvae in terms of where they live/experience?

Answer 36

larvae are under rocks and in soil- stable thermal environment
adults experience very variable environments

Question 37

how may hsp be used in cold stable environments?

Answer 37

as chaperones facilitating folding of proteins at low temps

Question 38

what is the expression of hsp like In larvae?

Answer 38

continuously expressed/upregulated

Question 39

what are the stages of the life cycle?

Answer 39

egg mass
1st instar
2nd instar
3rd instar
4th instar
pupa
adult

Question 40

when do they molt into adults?

Answer 40

in summer of second year