Task 3 pt2

Question 1

Sanger chain termination method

Answer 1

1. Target DNA is isolated and amplified with PCR
2. Double strands of DNA seperated with heated (95C)
3. Reaction is cooled to (50C) so that primer can attatch to a DNA strand
4. Reaction is heated again to (60C) so that DNA polymerase binds to primer and begins making new strand usin free nucleotides and ddNTP terminator nucleotides of specific base with fluresecent tag added
5. When ddNTP randomly binds to completeary DNA bases, terminates the chain
6. Cycle continues until all positions on tenplate strand identified

Question 2

Conditions for sanger method

Answer 2

Each ddNATP for each base is done in seperate sample tubes and after placed into different walls of gel electrophrises to see the length of terminated chains

Question 3

Case study for epidemic
Name

Answer 3

Equine infleueza Virus
strain of Influenza Type A Virus

Question 4

Case study for epidemic
Transmission

Answer 4

● Breeding stallions from Japan showed signs of EIV infection following importation
● Direct contact: Spread between horse via nasal discharges, can be inhaled by non affected horses
● Direct: Contaminated farm equipment (i.e. feed buckets and tack)
● Indirect: Humans can also carry the virus on skin, hair, clothing or shoes

Question 5

Case study for epidemic
management

Answer 5

● Govt put a halt on all movement of horse between locations
● Performed quarantine operations to isolate affected & unaffected horses
● Horses were given anti-inflammatory drugs to fight the virus

Question 6

Case study for epidemic
Preventative measures

Answer 6

● Ensure horses are up to date with vaccinations
● Continuous monitoring of strain
● Avoid sharing equipment between horses

Question 7

Case study for epidemic
Control measures

Answer 7

● Affected horses should be isolated from unaffected horses to minimise the transmission of disease.
● New horses should be quarantined for 14 days before grouping the new horses with existing unaffected horses.

Question 8

Animal disease
name

Answer 8

Foot and mouth disease

Question 9

Animal disease
Cause

Answer 9

Virus, apthovirus of the family Picornaviridae with 7 strains

Question 10

Animal disease
how does the pathogen enter the host

Answer 10

Through breath, secretions (spit, snot) and excretions (urine), animal products

Question 11

Animal disease
Effect on animal

Answer 11

Affecting: cattle, sheep, pig, cloven-hoofed wildlife
Symptoms: blisters, ulcers in mouth, shivering, loss of appetite/weight loss, depression, drooling/hyperventilation, fever, ruptured blisters,

Question 12

Animal disease
distrbution

Answer 12

Circulate 77% of global live stock population
Aus, NZ, Indonesia, Central, North America is free from FMD

Question 13

Animal disease
Prevention/control

Answer 13

Burning the carcasses, burying in mass graves, slaughters, euthanasian,
Quarantining new animals, foot washes, regular cleaning of pens, building, vehicles, equipment

Question 14

Animal disease
Effects on agriculture/economy

Answer 14

Case Study: UK 2001
* Total animals slaughtered: 6.5million animals euthanized/slaughtered
* Total cost to the economy: $13 billion

Question 15

Plant disease
Name

Answer 15

Panama disease (bananas) Fungus: Fusarim oxysporum

Question 16

Plant disease
Cause

Answer 16

TR4 strain –> affecting all banana species, Cavandish banana mostly

Question 17

Plant disease
Effect on plant

Answer 17

Symptoms
- Yellowing and browning of leaf margins
- Stem splitting at base of plant
- Does not affect the fruit

Question 18

Plant disease
Distribution

Answer 18

• Race 1, 2, 4 present QLD
• First detected in Aus near Darwin in1997,North Queensland in 2015
• Present in many South East Asian countries

Question 19

Plant disease
Prevention/control

Answer 19

Prevention
- Managing movement of soil, water, plant material entering and exiting farms
- Panama TR4 Grower kit –> latest info on disease and security practices
- Strict quarantine to slow down movement of fungus

Control
- Surveillance and compliance programs (self-reporting)
* Inspect bananas for disease
* Photos and documentation

Question 20

Plant disease
Effects on agriculture/economy

Answer 20

• Far North QLD grows 95% of Aus bananas
• Banana industry supporting income, jobs, produce
• Does not infect fruit
• Whole plantations wiped out
• Global loss of 18.2 billion USD

Question 21

Adaptions to faciliate entry
Prion

Answer 21

Adherance: Host B lymphocytes: secreting factors that enable prions to invade follicular dendritic cells in
lymphoid tissue.
Invasion: From lymphoid tissue, they invade nervous tissue through the autonomic nerves and travel to the brain.
● PrPSC is able to bind to surface of neuron → neuron synapse degradation

Question 22

Adaptions to faciliate entry
Viruses

Answer 22

Adhesion:
makes contact electrostatically to the cell’s host surface
Viral surface proteins coat adhere to host cell surface receptors
Enters the cell through endocytosis (most likely)
RNA viruses: must reach cytoplasm
DNA viruses: much reach nucleus

Question 23

Adaptions to facilitate entry
Bacteria

Answer 23

● Pili binding with the host cells’ surface receptor proteins
● Adhesins on the surface of the bacterial cell resist washing action of secretions such as urine, mucus, cilia.
● Translocation of bacterial proteins causes host cell membrane engulfment of bacteria.
enter a cell via phagocytosis

Question 24

Adaptions to facilitate entry
Protozoa

Answer 24

1. Receptors on the protozoan’s surface can bind with the host cell’s surface or cell
   membrane.
2. After successful binding, the protozoan secretes adhesive proteins to strengthen the attachment.
3. Next the protozoan begins to corkscrew itself through the
   cell membrane.
4. Proteins are then released to form a vacuole membrane around the
   protozoan to protect it from lysosome digestion.

Question 25

Adaptions to facilitate entry
Fungi

Answer 25

The hyphae are able to penetrate the host cell’s membrane by either:
* applying great pressure at a small surface area thus penetrating the cell membrane
* by secreting enzymes that can break down a portion of the cell membrane

Evasion mechanisms include:
* cell wall and capsules protect the fungus from host cell attack.
* heat shock proteins that allow fungi to tolerate body temps of 37°C
* reduced fungicidal power of macrophages
* suppression of cytokine production of host cells

Question 26

Adaptions to faciliate entry
Macroparasities

Answer 26

Eg. Ticks - can inject their mouth through the cell membrane and secrete saliva and neurotoxins into the cytoplasm. The saliva contains chemicals that stop the initiation of
the immune response.

Eg. Hookworms – larvae are able to penetrate the skin. Once they enter, they are carried via blood to the heart and lungs. Upon coughing and swallowing, they are transferred to the intestines where they mature and develop eggs.

Question 27

Adaptions to facilitate transmission
Air borne

Answer 27

● Able to remain suspended in air for long periods.
● Resists drying out.
● Pathogen causes sneezing and coughing, which causes ejection and transmission to the new host.

e.g. influenza virus

Question 28

Adaptions to facilitate transmission
Water-borne

Answer 28

● Able to colonise and proliferate in water, so environmental reservoirs are present (e.g. from faecal material).
● Modified outer surface structures (e.g. fimbria, flagella) allow motility.
● Many are not destroyed by simple boiling of water or other water-treatment processes.

e.g * Legionella

Question 29

adaptions to facilitate transmission
Vector-borne

Answer 29

● Pathogen not affected when absorbed by or bound to a vector. Therefore, they have adapted to survive inside the vector’s body.
● surface receptor proteins that can attach to vector → pili and adhesion proteins

e.g. malaria, dengue fever, zika virus

Question 30

Adaptions to facilitate transmission
Sexual transmission

Answer 30

● Ability to enter the uterus.
● Able to survive in placenta and transmit disease when organisms consume placenta.
e.g. HIV/AIDS, chlamidia

Question 31

Passive defence
Physical barriers

Answer 31

Thick cuticle, cell walls and small stomata → inhibit pathogen entry
○ Some pathogens secrete enzymes to break down the cuticle, and so plants with thicker cuticles are better able to withstand this.

Bark: protects pathogens from invading food source, sap, in the phloem beneath the bark tree

Question 32

Passive defence
Chemical barriers

Answer 32

● Antimicrobial chemicals such as nicotine which naturally occurs in some plants.
● Naturally occurring enzyme inhibitors.
● Stomata may close in response to the presence of bacteria, through chemical signalling methods involving detection of PAMPs.
(pathogen-associated molecular patterns)

Question 33

Active defence
Rapid active responses

Answer 33

● Plant recognitions → change in permeability of cell wall
○ Allows movement of ions & activates certain genes
● Release hydrogen peroxide in an oxidative burst → kill microbes directly
● Reinforcement of cell wall w/ aggregates of cytoplasm → cell wall apposition

Question 34

Active defence
Delayed active response

Answer 34

● Limit spread of pathogen
● Repair wounds in bark through cork cell production and gum secretion
● Lysozyme-like chemicals released
● Salicylic acid act as signals agent of subsequent infections and play a role in the plant’s ‘memory’ of a particular pathogen → system acquired resistance