Mod 7 Flashcards
(24 cards)
Louis Pasteur experiment outline
- Boil flask to kill pre-existing microorganisms
- Let it sit.
- When shaken and glass broken → the dust and microbes suspended in the air soured the solution.
‘Father of the germ theory:’ the idea that infectious diseases are caused by microscopic pathogens.
Proved microorganisms to live in air using a swan neck bottle flask.
Koch’s Postulates
Developed a set of protocols for proving the pathogens responsible for a given disease (no longer used practically).
- The microbe must be found in abundance in those suffering the disease and be absent in healthy individuals.
- The microbe must be isolated from a diseased individual and grown in a laboratory culture.
- The cultured microbe must cause disease if introduced into healthy individuals.
- When are-isolated from the experimental host, the microbe must remain identical to the originally isolated microbe.
Plant disease effects on Australia
Australia’s agriculture sector contributes to 3% of the country’s gross domestic product.
70% exported: Produce highly sought after.
Australia is FREE from…
Foot and mouth disease: hooved animals.
Fire bite: fruit markets.
The spontaneous generation of life theory
The theory that life could spontaneously arise from nonliving matter.
Disproven by Pasteur in 1862.
Vector transmissions
- indirect transmission
This occurs through arthropods or infected aquatic species that bites the individual or that is consumed by the individual.
Responsible for 17% of infectious diseases in humans.
Arthropods: Mosquitoes, flies, ticks, fleas, sandflies.
Mammals: Fruit flies, pigs.
Local factors of disease spread control
waste disposal, overcrowding, poor communication/road netwroks, animal husbandry practices, local cultural beliefs.
Regional factors of disease spread control
Geographical factor
Coastal regions
Increased trade of fresh food
Seasonal variations
Global factors of disease spread control
Refugee populations: Experience trauma, food insecurity, overcrowding, lack of basic health care, vaccinations alongside the limited health examinations conducted pre-migration.
Misuse of antibiotics: Rise in resistant bacteria, threatening global control
Communication
Effect of globalization on the spread of pathogens.
WHO: new diseases are emerging at an unprecedented rate due to globalization and increasing population numbers.
Since 1967: 39 new pathogens have been identified.
Antivirals
Used to control viral infections by inhibiting the virus development inside infected cells by inactivating its ability to envelope proteins, attach to host cells and replicate. HIV/AIDS Herpes Influenza Hepatitis B and C
Cons of antivirals
Is NOT curative.
Have greater efficiency if taken early on within treatment.
The high mutation rates of viruses → drug resistance.
Pharmaceutical companies that develop the drugs have an monopoly on the market → $$$$
Antibiotics
to kill the bacteria by interfering with the formation of the cell membrane, cell wall, and cell contents by interfering with DNA replication and other metabolic processes.
Penicillin
Cephalosporins.
Antibiotics pros and cons
Discovery of penicillin can be considered one of the greatest human discoveries.
Est. 200 million lives have been saved from penicillin.
Cell structures allow more easy targets.
Target can be wide or narrow.
Exclusive to bacteria.
Allergon
Can have side effects: nausea, diarrhea.
Antibiotic resistance due to the overuse.
Define epidemic
An outbreak of an infectious disease that spreads rapidly among individuals in a defined area or population.
Ebola 2013 - 2016.
Define pandemic
Typically the spread of a new disease across a continent or globe.
1918: Spanish flu.
Aboriginal medicines example
Aboriginal Australians are custodians of a rich and detailed knowledge of base medical native Australian herbs, fruits, and vegetables.
specialized preparation techniques were used.
Plant material often crushed and used as a poultice or infused in water to drink.
Often animal fat was incorporated to increase plant solubility and absorption rates in tissues.
Black bean: management of HIV
Biotroph
a plant pathogen that does not kill the host.
typically bacteria and viral infections
Necrotrophic:
infection that results in death of the host plant
typically fungal
Symptoms of plant fungi
Chlorosis
Leaf/stem wilting
Leaf bleaching
Leaf mildew
Symptoms pf plant virus
Chorisis
Yellowed leaves
Crinkled leaves
Stunted growth
Example of a plant fungi and its passive response.
Phytophthora Cinnamomi affects Eucalyptus Trees
- Causes leaf distortion killing tissue OR early defoliation.
- 1970s: structures 282,000 eucalyptus in Western Australia.
PHYSICAL BARRIERS Thick cuticles Cell walls Stomata Enzyme secretion Inhibit pathogen entry.
CHEMICAL BARRIERS
Chemical compounds in tissues.
Enzymes to break down pathogen-derived toxins.
Chemical receptors to initiate the next stage.
Example of a plant fungi and its active response
Phytophthora Cinnamomi affects Acacia Binervia (coastal wattle)
- Causes leaf distortion killing tissue OR early defoliation.
pathogenic recognition: from regulated genes in the cell wall.
rapid active response: The surface of the cell wall changes permeability in response to the proteins detected.
Activates expression of certain genes, such as the release of hydrogen peroxide to kill microbes
Delayed active response:
Limit spread
Repair wounds in bark: cork cell production.
Salicylic acid is released and acts as memory.
‘Systemic acquired resistance,’
Physical barriers to pathogen in mammals
Skin Mucous membrane Cilia Urine flow Peristalsis (muscle flexon): flex actions such as sneezing, flushing mechanisms.
Chemical barriers in mammal cells.
Stomach and acid enzymes
Tear enzymes: lysosome
Alkali pH in small intestine
