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MICR 271 > Module 6 > Flashcards

Module 6 Flashcards

1
Q

the GI tract contains some nerve tissue called the

A

Enteric nervous system (ENS)

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2
Q

the ENS is involved in

A

in digestion, controls blood flow, release of enzymes, etc

  • Connected to brain: gut-brain axis
  • May be impacted by gut microbes
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2
Q

the gut-brain axis is connected in a ___ which ____

A

bidirectional manner

coordinates the functions
of these organs under physiological conditions, or is deregulated in disease condition

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2
Q

types of signals/interactions of GI tract and CNS

A

Peripheral serotonin: cells in gut produce it which may affect signalling in the brain

immune system: gut can prompt production of cytokines that influence the brain

bacterial molecules: produce metabolites like butyrate that alter the activity of cells in the blood brain barrier

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2
Q

why is the intestinal barrier so important

A

Normally keeps bacteria in lumen, allows metabolites, water, etc, across barrier

If bacteria cross barrier, can cause inflammation - dysbiosis (loss of diversity)

Loss in barrier function implicated in health conditions

Gut microbiome impacts barrier function

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2
Q

impaired barrier function can lead to autoimmunity which is a ___

A

reaction to self antigens

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2
Q

how else is the GI tract connected to the brain

A

endocrine system, immune system, and metabolism

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3
Q

causes of autoimmunity

A

Food ingredients may resemble human proteins (Molecular Mimicry)
* Antibodies may then target human proteins

Food additives can change immunogenicity of nutrients
* May lead to antibodies targeting tight junction proteins

Changes to microbial composition
* May increase barrier permeability

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3
Q

connection of IBS with gut microbiota

A

associated with decreased diversity and an altered gut microbiota that increases the permeability of the intestine

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3
Q

connection of auto-immune disease and the gut microbiota

A

disruption of barrier function of the tight junctions

bacteria/microbes get in and cause chronic inflammation

inflammation can cause further damage and the cycle continues

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4
Q

impaired barrier function contributes to

A

dysbiosis, inflammation, disease

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4
Q

what is the great plate count anomaly

A

Number of bacteria counted under a microscope is far
greater than number observed by plate counting
-hard to cultivate bacteria (we dont know their growth factors) easy to just observe

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5
Q

many bacteria are isolated from ___

A

soil organisms (most species in the environment cannot be cultured)

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5
Q

why are we limited in getting antibiotics from the soil

A

we simply cannot culture them: untapped resource

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5
Q

describe an iChip

A

Device used to grow microorganisms

Semi-permeable membranes on sides

Device (containing microorganisms) inserted into soil sample
-‘Natural’ environment for these microbes

Allows microbes to grow, produce teixobactin

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5
Q

teixobactin was discovered using ___

A

iChip

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6
Q

teixobactin targets what kind of bacteria

A

Gram + cell wall synthesis, it binds to lipid II (peptidoglycan precursor)
and to lipid III (teichoic acid precursor)

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7
Q

what is the most effective way to find a new antibiotic

A

search for pre-existing compounds

7
Q

describe genome mining

A

based on analyses of genes, we can predict the functions of them
-based on genetic sequences: what are they producing
-genes that are present

we are mining for useful products

found a strain with genes involved in phosphonate biosynthesis that had antimicrobial properties

7
Q

What is one possible reason for why there is a difference in the way bacteria grow and multiple in a petri dish vs in a natural environment

A

Bacteria don’t like to grow in unfamiliar environments where they will probably be killed by predators or unfamiliar conditions

7
Q

how do siderophores help facilitate the growth of normally unculturable bacteria

A

secreted by bacteria to bring iron from the environment into the cell
-these factors can be added to the petri dish

8
Q

yeast is used to ferment __ and produce __

A

glucose, ethanol via glycolysis

9
Q

downside of using yeast to produce ethanol

A

the process produces ATP which the yeast uses to replicate and increase its biomass, taking energy away from the process of making ethanol

9
Q

an example of a biofuel

A

ethanol

9
Q

Pros and cons of Z. mobilis to making ethanol

A

Pro: less ATP so less energy diverted to increasing biomass, can survive in greater ethanol concentrations

Cons: cannot use many sugar substrates, some have to be pretreated

10
Q

Z mobilis makes ethanol via the ____ pathway

A

Entner-Doudoroff

11
Q

what is bioremediation

A

the use of microbes to control pollution (native or deliberately introduced)

11
Q

microbial biosensors

A

artificial systems where we manipulate microbes to sense a certain environmental stimulus

Two component system (we can put certain genes under control)

can engineer pathways

11
Q

how do microbes bioremediate radioactive substances

A

convert radionuclide into a more controllable, insoluble, stable form (biomineralization, enzyme-catalyzed modification)

11
Q

bioremediation by genetically engineered species

A

identify genomes of organisms that survive in the waste - genes contribute to detoxification, genetically engineer to express at high levels

12
Q

how do bacteria sense the environment

A

two component systems

13
Q
A
13
Q
A
14
Q

why is wheat straw generally not digested well by animals, how can it be made more digestible

A

it has high tannins (can be targeted by microbial enzymes) and lignin ( can be targeted by fungi) in its cell walls

14
Q

why do streptomyces produce antibiotics

A

antibiotics are a secondary metabolite to protect their nutrient sources from other microbes, and they themselves have genes that protect them from their antibiotics (spreads via HGT)

14
Q

key antibiotics to the antibiotic era

A

Penicillins produced by Penicillium mold

Streptomycin produced by Streptomyces griseus

Other antibiotics produced by other Streptomyces spp (Sulfa drugs from dye) - came from soil

15
Q

what are some of the ways vaccines are made

A

attenuated microbes (treat them so they are no longer infectious, safe form)

dead microbes (kill the bacterial cells)

components of microbes (take different molecules and administer them - immune system makes antibodies)

16
Q

the general workflow of testing vaccines

A

solution preparation

preclinical trials

clinical trials

17
Q

what is the medicinal value of E. coli

A

it can produce human insulin

  1. The Initial process of insulin manufacture is the insertion of synthetic DNA coding for A and B chains of insulin into two plasmids.
  2. The next step is to insert the two plasmids separately into Escherichia coli.
  3. Then, the A and B chains are purified from the two bacterial cultures.

4.Finally, the purified A and B chains are recombined to produce the full insulin molecule.

17
Q

what is one of the most virulent food born pathogens

A

listeria monocytogenes (can spread from GI tract to blood causing systemic infection)

18
Q

probiotic

A

live microorganisms that confer health benefit

  • No legal definition
  • Products may be marketed as probiotics even if no
    demonstrated benefit
19
Q

prebiotic

A

food ingredient that stimulates growth/activity of
certain gut microbes

20
Q

what is an effective probiotic

A

Lactobaccilus spp

21
Q

how does L. rhamnosus GG work

A

secretes proteins P40 and p75 (protective effect)

activate a host cell receptor EGFR

Two pathways
-upregulation of genes that protect/repair tight junctions
-upregulation of genes that block signals of apoptosis in endothelial cells (no hole in wall)

MICR 271 (6 decks)

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