Global amphibian declines Flashcards

1
Q

how many species of amphibians

A

5,700

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2
Q

since 1980 how many amphibian species have experienced rapid decline

A

1/3rd

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3
Q

nearly 2,000 species

A

–> that have gone completely extinct

–>gone extinct in the wild but have captive breeding programs at zoos

–> have potentially gone extinct

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4
Q

massive extinctions being called

A

the most spectacular loss of vertebrate biodiversity in recorded history

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5
Q

name a disease which is causing an amphibian scourge

A

Batrachochytrium dendrobatidis

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6
Q

Bd is a

A

chytrid fungus

  • aquatic and motile
  • causes severe disease in amphibians
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7
Q

over the past 30 years

A

lots of research has poured into research regarding the amphibian scourge

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8
Q

in 1997 some of that research paid off

A

with the very important discovery of the chytrid fungus, Bd

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9
Q

Chytrid fungi are

A

heterotrophs

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10
Q

heterotrophs

A

sequester carbon from other life sources, not the sun–> saphorhphytes and parasites

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11
Q

Bd life cycle

A

1) bd starts as a tiny zoospore that swims in open water
2) when it find suitable host, it burrow deep into the skin and develops into a thallus
3) thallus matures into a sporangium- egg-sac
4) the sporangium grow until they burst open and new zoospores are released
5) these zoospores swim around and find new hosts, or re-infect the same host and cause chronic disease

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12
Q

Bd life cycle take

A

4-5 days

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13
Q

Bd causes a chronic skin disease called

A

chytridiomycosis- colonised keratinised skin layer

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14
Q

hyperplasia and hyperkeratosis causes

A

disrupted electorylye balance

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15
Q

chyridiomycosis leads to

A

cardiac arrest and death due to disrupted electolye dance

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16
Q

amphibian ski is

A

tremendously improtnant

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17
Q

amphibians use their skin to

A

drink- rarely drink through mouths- especially when underwater

18
Q

chytrdiomycosis

A

chronic infection causes skin to thicken and scar- dehydrating the amphibian leading to their death

19
Q

Bd infected populations can

A

crash within just a few short months- before anyone knowns the population has become infected

20
Q

chytrdiomycosis is not

A

easy to diagnose due to no hallmark symptoms

21
Q

two main methods for diagnosing Bd infection are quantitative …

A

qPCR and histology

22
Q

qPCR requires

A

an amphibian wiped down with a swab and that swab being sent away to a diagnostic lab
–> CANNOT BE DONE ONSITE

23
Q

downside to qPCR

A
  • cannot be done onsite
  • need trained staff
  • expensive equipment (>£10,000)
  • expensive reagents

£40 per test

  • by the time you have the result, frog has been set free- cannot reat
24
Q

alternative to qPCR

A

histological examinaiiton

25
Q

histological examination

A

microscopic examination of skin

26
Q

downside of histological examination

A

requires extensive knowledge of infected and uninfected skin morphologies and requires you take an actual skin sample from the frog

  • usually have to take from dead amphibian
27
Q

its providing

A

extremely difficult to monitor BD infections in real time

28
Q

which monoclonal antibody has been chosen to act as an immunotherapy for Bd

A

mAb 5CO4

29
Q

benefits of mAb5CO4

A
  • grows quickly
  • produces lots of antibody
  • very robust
  • does not require supplementation to grow well
30
Q

next it became important to know where the antigen(glycoprotein/ carbohydrate) to mAb 5C4 was located.. inside? outside? Zoospores? Sporangium? how did they do this

A

using immunofluorescence- found to be on outside of spores

31
Q

name a better way to diagnose Bd- to help tracking and prevention of disease

A

lateral flow assay

32
Q

what must a test be to track Bd

A
  • it must be inexpensive and widely used
  • rapid
  • immediate results
  • easy to use
33
Q

how to LFA work

A

a small amount of liquid is placed on the sample pad and capillary action pulls the fluid across the membrane where it encounters:

  • a test line- this only appears if you are infected
  • a control line: always appears- ensures test ran completion
34
Q

which antibodies are used in LFA

A

labeled and immobilised 5C4 Ab

35
Q

if the antigen is present in the sample (e.g. the frog has the disease)

A

then the antigens bind to the labeled (gold) 5C4Ab and then binds to the immobilised 5C4 Ab antibody (test line)

36
Q

if the antigen is not present the labeled 5C4 Ab will bind to

A

the control line label antigens

37
Q

OID can be used to study

A

antibody-antigen interactions and to determine whether proteins share antigenic determinants

38
Q

IF and EM-gold can be used to

A

visualise the extracellular and intracellular location of antigens or antibodies in the cell

39
Q

western blotting can be used to

A

identify individual antigens in a mixture of proteins

40
Q

Lateral flow assays are

A

semi-quantitiaitev point of care tests