Gut microbiota, immunity and infection Flashcards Preview

2020 MHS microbiology unit 2 > Gut microbiota, immunity and infection > Flashcards

Flashcards in Gut microbiota, immunity and infection Deck (20)
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using concentrations  of soluble chemicals to affect microbial community behavior

quorum sensing


microbial species that usually peacfully colonizes a host but has the potential to cause disease



a biofilm of microbes found inside a living being



what are five benefits for microbiota. ultimate goal of microbiota (2)

  1. synthesize essential metabolites
  2. break down plant fibers in food
  3. inactivate toxic substances in food or made by pathogens
  4. prevent pathogens from benefiting from the resources of the human gut
    1. compete fro attachment. food and generate antimicrobial compounds
  5. interact with epithelium to trigger development of secondary lymphoid tissue
    1. development and homeostastic maintinence of host immune system

ultimate goal

  1. regualates gut development
  2. produces hormones that tell the host to store fat


explain the microbes that are required for immune system development and how they colonize the growing person

  1. prenatal
    1. very little microbiota
  2. postnatal
    1. IgA from breask milk blocks bactria from translocating 
      1. limits damage from colonizing microbes
    2. colonization sets stage for commensal tolerance and anti pathogen defenses
  3. infant
    1. colonization leads to rapid immune structure 
      1. peyers patches
    2. tolerogenic enviornment helps acoid excessive anti microbiota
  4. childhood
    1. Tregs are required for homestasis and are expanded by certain  microbial products 
    2. iNKT cell (inflammatory) number inversely related to microbiotoa colonization
      1. more colonization = fewer iNKT


epinephrine and norepinephrine have what type of effect on biofilm formation?

epinephrine and norepinephrin increase biofilm formation

  1. can induce growth or death of microbes


what are three influences on microbiota?

  1. age
    1. colonization ends ~2/3
    2. stable from2/3-80
    3. post 80
      1. increase in bacteroides and eubacterium 
      2. decrease in lachnospiraceae
  2. diet
    1. changes in diet have responsive changes in microbiota
    2. effect of diet on non-gut microbiota is unclear
  3. lifestyle
    1. housemates more similar than non-resident family
    2. urban vs rural
    3. country vs residence
    4. sleep
      1. bacteria have a circadian rythm
      2. may hve links to health risks of shift work and jet lag


What does leads to tooth decay?

Tooth decay occurs with acid fermentation that deminerlaizes tooth enamel

some strains form a glacalyx to adhere to oral cavity and each other


microbiota are first inherited from

species are inherited from the mother

  1. some species more heritable than others
  2. similar to gene that are passed down from ancestral origins


what are four implications for microbial disruption early in life?

  1. long-term consequences including increase risk of
    1. autimmunity
    2. chronic inflammation
  2. linked to
    1. antbiotics use
    2. improved santation
    3. consumption of processed foods( high fat/carb and low fiber)
  3. limits microbial diversity
  4. depletes "educational bacteria leading to immune over reaction to subsequent challanges


what are the ages that gut microbiota is stable?

age where it slowly is colonized?


  1. generally stable from 2/3 yrs - 80 yrs old
    1. older individuals increase bacteriodes and eubacterium while decreasing lachnopiraceae
  2. slowly colonized until age 2/3- then microbiome reseembles adult


how long does it take for a fast to implicate changes in the gut mirobiota?


as little as a day


which of the following does not have an implication on gut microbiota

  • age
  • diet
  • lifestyle
  • phsrmaceuticals
  • genetics
  • environement
  • depression


who has a more similar gut microbiota

  • family members on the other side of the world
  • room mates

room mates


explain how jet lag may be linked to gut microbiome

microbiota  have a circadian rythem that is linked to the hosts. changes in spatial location in the intestine, species abundance and metabolite secretion - may link to shift work and jet lag. ultimatly your bacteria have a sleep cycle that mirrors yours


The stomach has what type of bacterial formation?

explain why

the stomach has a harsh acidic enviornment, leading to  low colonization

  • vibrio cholera dies in the stomach of healthy individuals to this scidicty

mucosal lining of the stomach is less acidic and acts as a moderate location for colonization


microbes living in the stomach live where? why

microbes survive the stomach and colonize the lining

mucosal lining of the stomach is less acidic and acts as a more moderate location colonization


The bacteria are vulnerable to what items in the stomach and duodenum?

stomach- pH

duodenum - bile salts


where is the diversity of microbes the highest?

large intesine


puts the positive pressure on the microbes. How can the bacteria survive



  1. bile salts
  2. hydrolases