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Microbiology post midterm > Lecture 31-33 > Flashcards

Lecture 31-33 Flashcards

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Biology 101 flashcards
1
Q

What is biocontrol?

A

Definition:

-A method of introducing an agent organism into a new ecosystem to naturally prey on a suppress target pest organism

Agent:

-The newly introduced species-Predator

Target:

-The defined pest, whose population is suppressed by the agent-Prey

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2
Q

What is the purpose of biocontrol?

A
  • Biocontrol decreases but does not eradicate target species

- Biocontrol effective for farming to reduce invasive pests without using pesticides, GMO’s

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3
Q

What are the three case study examples?

A
  1. Viral
  2. Bacteria
  3. Fungal
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4
Q
  1. Myxomatosis to suppress explosive European rabbit population in Australia
A
  1. Myxoma virus
    - Enveloped virions
    - Brick shaped with a bio concave core
    - Non-segmented linear ds DNA genome
    - During lifecycle produces proteins that interfere with host immune systems (capsases)
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5
Q

What is myxamotosis?

A
  • Lumps (myxomata) and puffiness appear around the head and genital area
  • Progresses to acute conjunctivitis
  • Loss of appetite, fever, listlessness
  • Death within 14 days, usually less than 48h
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6
Q

What was the plan and were they successful?

A

Problem: too many rabbits, too few predators
Initiative: Introduce virus to suppress rabbits
Desired Result: Reduce rabbit population

-Many rabbits grew resistant to the virus

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7
Q

Case study 2: Bacteria drastically reduce crop lost to insects

A
  • Bacillus thuringiensis
  • Toxin produced by bacteria is protective to the plant
  • Delta endotoxins are proteins produced during Bacillus thuringiensis SPORE formation
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8
Q

Bacillus thuringiensis

A
  • Common soil bacteria
  • Produces crystalline toxin during sporulation
  • As proteinaceous inclusion crystals, Cry
  • Cry genes located on a plasmid
  • Makes insects cry
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9
Q

What is the mechanism of actions of cry toxin?

A
  • It causes sepsis and death of the insect
  • Happens in the gut
  • ALP, APN and CAD.
  • Cry toxin binds to CAD and it is activated and then it oligomerizes with the help of ALP and APN
  • Then the toxin complex forms pores in cell membrane
  • The membrane is disrupted, the ion channel is disrupted.
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10
Q

What are the other strains of BT that protect against different insects?

A
  1. Kurstaki Strain-targets leaf and needle feeding caterpillars
  2. Israelensis-targets mosquitoes and black flies
  3. San Diego Strain-targets beetles
  • The more specific the agent the more controlled the intervention and fewer unintended consequences arise
  • Narrow host range is the key
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11
Q

What is the BT GM CROP

A
  • Bt crops were among the first GM croops
  • Cry genes inserted into plant genomes
  • Expressed by plant to confer resistance to insect plants
  • Controversal for use in food crops
  • Have been in textile crops for many years
  • Bt cotton
  • Pest resistance to Cry is a problem
  • Secondary pest infestations can emergy
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12
Q

Case study 3: Research discovers new uses of fungus to protect food

A
  1. Tricoderma harzianum
  2. Plasmopara viticola
  3. Downy mildew infection
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13
Q

Trichoderma harzianum

A
  • Fungus of Ascomycota divison
  • Most prevalent culturable fungus in soil
  • Mycoparasites
  • Attack and kill a wide range of fungi
  • Some of which are problematic pathogens of plants
  • T. harzianum is problematic itself in the mushroom growing industry
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14
Q

Plasmopara viticola

A
  • Cause of downy milder of grapevines
  • Devastating crop disease
  • 50-100% crop loss can occur

P. viticola oocytes germinate in the spring
-Cold T and wet soil

  • Released zoospores require surgace wetness to infect the host
  • Infection takes place only through the stomata
  • Hyphae grow intercellularly, damaging plant tissue
  • The pathogen sporulates through stomata during warm, humid nights completing the lifecycle
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15
Q

Benefits of T. harzianum

A
  • Easy to apply
  • Often dried and powedered for use as a root dip
  • Associates with roots and helps to solubilize phosphates and micronutrients for plant uptake
  • Product lytic enzymes with activity against other fungi, including P. viticola
  • Induces deferense responses in many crop plants
  • Providing natural resistance against pathogens
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16
Q

What are the risks of biocontrol?

A

-It is important to RESEARCH

  1. Unintentional targeting of non pest species
  2. Provides competition with existing predators
  3. Unintentional transport, introduction and evolution of parasites
  4. New species can have unintended effect on large ecosystem
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17
Q

Define: Classical biological control 1.

A
  1. Learning how to manage biocontrol
  • Control of pests introduced from another region through importing specialized enemies of the pest from their native range,
  • Aim: to establish a sustained population of the new enemies
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18
Q

Define: Conservation biological control

A

-Manipulation of the environment to favor natural enemies of the pest

19
Q

Define: Augmentation biological control

A
  • Number of biological control agents is supplemented
  • Commonly used when biocontrol agent cannot adapt and survive long term in the new environment

Inoculation:
-Introduction of a small number of individulas of the biological control agent

Inundation:
-Introduction of vast number of individuals

20
Q

Microbial Bioremediation

A
  • Microroganism mediated transformation or degradation of contaminants into non hazardous or less hazardous substances
  • Most pollutants can be broken down or detoxified by microbes under ideal conditions
  1. Plastics
  2. Radioactive compounds and heavy metals
  3. Halogenated products
21
Q

Could microbes help in plastic recycling?

A

-On land optimal conditions can be managed

  • In the ocean, no
    1. Cold T
    2. Salinity
    3. Dilution
    4. Depth (P)

-Microbes found to be part of the biofilms that form on plastics in the Arctic and Antarctic regions may be useful for biodegradation,
Many are novel species

22
Q

What is mutagenomics?

A

-Taking a sample, fragemnt DNA and the computers puts it together and tell us which species it is.

23
Q

Has microbe diversity been eroded?

A

Missing microbe hypothesis

-loss of microbiota generally compounds over generations and recent changes in lifestyle have greatly affects

24
Q

Missing microbiota hypothesis

A
  1. Prevotella strains, fiber degrading enzymes

2. Bacteroides strains

25
Q

What is gut dysbiosis?

A

A black box=Reduced microbiota diversity+poor lifestyle choices+poor diet
-We don’t have a definition of what is normal

26
Q

What are probiotics?

A

-They are alive organisms that when administred in adequate amounts confer a health benefit to the host

  1. Fermented foods are NOT probiotics
  2. Fecal transplants are NOT probiotics
27
Q

When choosing a probiotic look for

A

a strain and clinically approved

28
Q

What are prebiotics?

A
  • Food for your gut microbes
  • Typically non digestible fibre compunds
  • Not a one size fits all approach
29
Q

Fermented foods

A
  • Naturally transformed by microbes to create novel textures and flavours
  • Benefits of fermented food may not be the microbes but their chemical products of fermnetation
  • Small organic molecules (short a.a, alcohols, esters, amides) diffuse through the membrane
30
Q

How do microbes talk?T

A

Through small organic molecules

31
Q

Fecal transplants

A

-C. diff infections in cure of 90%

32
Q

Her lab solutions

A

Met-1= 33 bacterial strains
-Old women
-Really sick
Instead of poop use a complex, defined ecosystem of pure microbes
-Bc it is defined we can monitor long term effects

33
Q

Microbes as food: FUNGI

A

-edible fungi includes compost grown AGARICUS BISPORUS

  • Button and Portobello mushrooms
  • Grown in the dark on manure

-Some fungi are grown by inoculating spawn into logs of wood

34
Q

Edible algae

A
  • Red algae Porphyra can be toasted in sheets and used to wrap sushi
  • Carbohydrate active enzymes made by the gut microbiota helpt to process carbohydrates to provide calories for the host

-Transfer of Porphyranases genes to the gut microbiota of people who traditionally eat a lot of nori

35
Q

Spriulina

A
  • Most single celled microbes cannot be eater
  • Contain a large amount of nucleic acids
  • Purinesp-uric acid which is degraded to and it is causes diseases

-Spirulina has a low purine contenT
Rich in B12, protein and minerals

36
Q

Fermentation of Food (3 reasons why it is conducted)

A
  1. Perservation
    - Fermentation products limit growth of microbes and preserve food
  2. Improvment of digestibility
    - Fibrous macromolecules in meat and vegetables can be broken down by microbial action
  3. Addition of nutrients and flavours
    - Fermenting foods makes vitamine, B12, as well as compounds that generate flavour
37
Q

Acidic fermentation for cheese

A
  • Used for cheeses and sausages
  • Primarily made by Lactobacillus

Carbohydrates-glucose-pyruvic acid-lactic acid-propion acid, acetic acid, water, co2

38
Q

Heterolactic fermentation

A
  • Used for fermentation of some vegetables
  • Sauerkraut
  • Acidic fermentation
  • Carried out by LECUONOSTOC
39
Q

Ethanolic fermentation

A

-No lactic acid is used in the leavening of bread and the production of alcoholic beverages

  • Alcholic fermnetation
  • Carried out by yeast
40
Q

Alkaline fermentation

A
  • Generates ammonia which results in a ph rise
  • Beans and vegetables can be fermenteted in this way
  • Bacillus is the bacteria

-Pidan and Natto

  • Bacillus breaks down the bad components of soy bean and makes it more difestible
  • 100 year old egg
41
Q

Soy beans fermentation

A
  • Source of protein but contain a lot of phytates, protesease
  • To reduce the levels of these, but maintain the protein levels of the bean, ACIDIC fermentation is used
  • Ofteen bacterial and mold fermentation is carried out together in succession
  • Acidic fermentation of soy (with rice or wheat) by Aspergillus oryzae generates glutamic acid
  • Soy sauce and miso
42
Q

Brine fermentation

A
  • Kimchi
  • Salt limits the number of microbial species, offers some control of the process

-Kimichi is an examples of complex fermentation with at least 3 microbial species

43
Q

Chocolate

A
  • Complex food fermentation
  • No started culture has yet been commercialized
  • Must be close to the harvesting on the forest floor
44
Q

Baker’s yeast

A

-The champion fermenter
-Brewers yeast
S. cerevisiae

-The CO2 is useful in bread and beer

Microbiology post midterm (5 decks)

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