Microbiome 8.2 Flashcards
The Intestinal microbiota offer protection against enteric pathogen infections through?
(3 THINGS)
(I) Saturation of colonization sites and consumption of nutrients limit pathogen access to host tissues;
(II) the microbiota prime innate immunity by stimulating MUCIN PRODUCTION, immunoglobulin (Ig)A, and antimicrobial peptides (AMPs)
(III) microbiota stimulate INTERLEUKIN (IL)-22 expression, which increases epithelial AMPs, and IL-1β production, which promotes recruitment of inflammatory cells
We tend to emphasize _____ microorganisms (pathogens) but more microorganisms are beneficial than harmful
harmful
2 catagories of beneficial microorganisms
Commensals
Mutuals
define Commensals microorganisms
where two organisms live together and one benefits and the other does not
define mutual microorganisms
where two organisms live together and both benefit by this interaction
*most microbiomes, may be only place a microbe survives
Microbiota (microbiomes) are independent or interacting populations
interacting populations
The environment in which a microbiome lives is its
habitat (The oral cavity is a microbial habitat)
The collection of organisms in the oral cavity is called the?
oral Microbiota
Ecosystem refers to all of the?
living organisms PLUS physical and chemical constituents in an environment (The oral cavity is an ecosystem)
Microbial Ecology is the study of?
microbes in their natural environments
Diversity and abundances of microbes are controlled by?
resources (nutrients) and environmental conditions (e.g., salinity, temp, pH, O2)
The activities of microbial communities can affect the _______ and _____ properties of their habitats
chemical and physical
define Cooperation
each species of microbe contributes something to the microbial community for the good of all members of the community
define competition
each species of microbe is in competition with other species of a microbial community and will do anything it needs to maintain its niche (this usually dictates the number of member of each species in an environment)
warfare definition
bacteriocins (e.g., colicins produced by Escherichia coli), other antibacterial proteins, and metabolites that deter other species from growing
the best studied of the human microbiomes is?
the gut
Microorganisms in the colon can live as?
commensals, mutuals, OR pathogens
Many Microorganisms in the colon assist in what 3 common things?
1) digestion
2) synthesis of vitamins, nutrients, metabolites
3) out-compete certain pathogens
how do Microorganisms in the colon assist in digestion?
Bacteria in the human gut are responsible for metabolizing complex carbohydrates (including cellulose) to provide small-chain fatty acids such as acetate, propionate,
and butyrate that can be readily transported and used by the cells of our body
The gut microbiome has been shown to be critically involved? (6)
- in our behavior
- in development of our immune system
- development or prevention of obesity
- in development of inflammatory disease
- development or prevention of cancer
- in the success or failure of cancer immunotherapy
Does our body or our alimentary tract have more cells?
The alimentary tract- has more bacterial cells than our own cells in our entire body by a factor of 10!
Of the approximately 200 unique species of bacteria that colonize the gut, most are members of?
- Actinobacteria (e.g., Bifidobacterium)
- Bacteroidetes (e.g., Bacteroides)
- Firmicutes (e.g., Eubacterium, Ruminococcus, Faecalibacterium, Blautia)
Can gut bacteriophages in the gut be seen in circulation?
Yes. bacteriophages are absorbed and can also be found in blood circulation
A significant part of this microbiome are the ______ that regulate the bacterial microbiome
bacteriophages
define mucins
a glycoprotein constituent of mucus
Some of the bacteria in the gut graze on the carbohydrates, the ____ that line the epithelium
mucins
In regards to oxygen, the large intestine is?
anaerobic
what part of human biome has the highest bacterial content?
Large intestine; 1010 to 1011 per gram
T or F. •Microbiota of intestine is stable
TRUE. remarkably stable like a fingerprint or genetic signature
T or F. Many bacterial species are loosely attached to gut
FALSE. they are FIRMLY attached, otherwise they’d be washed away with food
What does Pili enable the microbes to do?
1) colonize the epithelium of specific host organs
2) help microbes stay in the intestinal tract by binding to human mucus or mannose sugars present on intestinal surface structures
T or F. Antibiotics have a profound effect on the composition of the microbiota
TRUE.
During and after a 5-day course of oral ciprofloxacin there is a decreased diversity in ____ microbiota?
gut
**roughly one third of the bacterial taxa changed during ciprofloxacin administration
A study of the human fecal microbiota demonstrated that a 7-day course of clindamycin reduced diversity within the _____ genus and led to increased frequencies of highly antibiotic-resistant clones
Bacteroides genus
what causes meningitis?
Nesseria meningitidis
