Module 6 Flashcards
the GI tract contains some nerve tissue called the
Enteric nervous system (ENS)
the ENS is involved in
in digestion, controls blood flow, release of enzymes, etc
- Connected to brain: gut-brain axis
- May be impacted by gut microbes
the gut-brain axis is connected in a ___ which ____
bidirectional manner
coordinates the functions
of these organs under physiological conditions, or is deregulated in disease condition
types of signals/interactions of GI tract and CNS
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
why is the intestinal barrier so important
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
impaired barrier function can lead to autoimmunity which is a ___
reaction to self antigens
how else is the GI tract connected to the brain
endocrine system, immune system, and metabolism
causes of autoimmunity
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
connection of IBS with gut microbiota
associated with decreased diversity and an altered gut microbiota that increases the permeability of the intestine
connection of auto-immune disease and the gut microbiota
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
impaired barrier function contributes to
dysbiosis, inflammation, disease
what is the great plate count anomaly
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
many bacteria are isolated from ___
soil organisms (most species in the environment cannot be cultured)
why are we limited in getting antibiotics from the soil
we simply cannot culture them: untapped resource
describe an iChip
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
teixobactin was discovered using ___
iChip
teixobactin targets what kind of bacteria
Gram + cell wall synthesis, it binds to lipid II (peptidoglycan precursor)
and to lipid III (teichoic acid precursor)
what is the most effective way to find a new antibiotic
search for pre-existing compounds
describe genome mining
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
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
Bacteria don’t like to grow in unfamiliar environments where they will probably be killed by predators or unfamiliar conditions
how do siderophores help facilitate the growth of normally unculturable bacteria
secreted by bacteria to bring iron from the environment into the cell
-these factors can be added to the petri dish
yeast is used to ferment __ and produce __
glucose, ethanol via glycolysis
downside of using yeast to produce ethanol
the process produces ATP which the yeast uses to replicate and increase its biomass, taking energy away from the process of making ethanol
an example of a biofuel
ethanol
Pros and cons of Z. mobilis to making ethanol
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
Z mobilis makes ethanol via the ____ pathway
Entner-Doudoroff
what is bioremediation
the use of microbes to control pollution (native or deliberately introduced)
microbial biosensors
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
how do microbes bioremediate radioactive substances
convert radionuclide into a more controllable, insoluble, stable form (biomineralization, enzyme-catalyzed modification)
bioremediation by genetically engineered species
identify genomes of organisms that survive in the waste - genes contribute to detoxification, genetically engineer to express at high levels
how do bacteria sense the environment
two component systems
why is wheat straw generally not digested well by animals, how can it be made more digestible
it has high tannins (can be targeted by microbial enzymes) and lignin ( can be targeted by fungi) in its cell walls
why do streptomyces produce antibiotics
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)
key antibiotics to the antibiotic era
Penicillins produced by Penicillium mold
Streptomycin produced by Streptomyces griseus
Other antibiotics produced by other Streptomyces spp (Sulfa drugs from dye) - came from soil
what are some of the ways vaccines are made
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)
the general workflow of testing vaccines
solution preparation
preclinical trials
clinical trials
what is the medicinal value of E. coli
it can produce human insulin
- The Initial process of insulin manufacture is the insertion of synthetic DNA coding for A and B chains of insulin into two plasmids.
- The next step is to insert the two plasmids separately into Escherichia coli.
- 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.
what is one of the most virulent food born pathogens
listeria monocytogenes (can spread from GI tract to blood causing systemic infection)
probiotic
live microorganisms that confer health benefit
- No legal definition
- Products may be marketed as probiotics even if no
demonstrated benefit
prebiotic
food ingredient that stimulates growth/activity of
certain gut microbes
what is an effective probiotic
Lactobaccilus spp
how does L. rhamnosus GG work
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)
