Unit 4: Chapter 33 Flashcards
Microbiome
all gene’s found in one’s microbiota
Microbiota
all the microorganisms that live in and on an organism
The number of genes present in the microbiome is over
1 million
Holobionts
hosts and microbes live together and evolve together
Example of holobionts
humans
Humans cannot live a ____ _____ without their microbial partners
normal life
Goal of first phase of human microbiome project (HMP)
Characterize the human microbiome
____ reveal these microorgnaisms of holobionts
16S ribosomal RNA sequencing
Work of Human microbiome project showed each person
harbors a unique collection of microorganisms
Each microbial niche is related to variety of factors including:
body location, age, sex, diet, and environment
More than half your body is not _____
Human
Microbiota community is not ____
static (unchanged)
Microbe develops from birth to adulthood into ______
stable microbiome
Goal of second phase of human microbiome project (HMP)
Seeking to explore thre microbiome related conditions
1. pregnancy and preterm birth
2. irritable bowel syndrome
3. type 2 diabetes
Microbiota begins developing at ____ and changes as we ___
birth, age
Stable community of microbes adopted by age
3
Important to develop a ___ microbiome
diverse
More diverse microbiome linked to better health
Vaginal birth provides exposure to microbes from _____
mother’s birth canal
Cesarean delivery (C section) provides exposure from
initial caretakers
______ provides bifidiobacteria
Breastfeeding
Bifidiobacteria
transport polymeric sugars which are foudn in breast milk directly across plasma membrane
Bifidiobacteria fermentation of sugars
Provide acetate and lactate which provides infant with calories and lowers pH which limit growth of pathogens
Why is low pH good for infants?
Fermentation products of acids lower pH and limit growth of pathogens
Bifidiobacteria are required for normal development of _____________
gut associated lymphoid tissue (GALT)
Gut associated lymphoid tissue (GALT)
essential componet of host defense against pathogens
Since Bifidio is needed for GALT (gut associated lymphoid tissue) it is asspcoated with
limiting or preventing fodborne disease
Why do babies benefit from breast feeding milk compared to cow milk?
Cow milk does not support immunity
______ impact microbial diversity
Environmental factors
(travel, job changes, diet change, foods)
Even though stable microbiota since 3, can change due to
physical or life style changes
If you work in hospital, have lots of _____ microbiota
Transient
Stable microbota:
resident and established
How is human microbiota variable
From person to person and at different sites within a person
transinent microbiota
nonresident and no stable relationship
Bacteria common to human skin, intestinall tract, and other mucosal surfaces include 6 major phyla:
- Actinobacteriota
- Bacteriodota
- Firmicutes
- Fusobacteriota
- Proteobacteria
- Verucomicrobiota
Verucomicrobiota
Gram negative
Bacteria common to human skin, intestinall tract, and other mucosal surfaces are mostly gram
gram negative
True or False: Archaea, fungi, viruses can be in your microbiota
True
What is #1 common organism?
Staphylococcus epidermis
What is skin bacteria?
Staphylococcus epidermis
Function of staphylococcus epidermis
Colonize skin, generally nonpathogenic, and key componet of healthy skin
Staphylococcus epidermis modulate keratinocyte gene expression stimulating _________ which kills transient microbiota
Antimicrobial peptide release
Staphylococcus epidermis secreting products of _______ called ______
fermentation, short chain fatty acids
Skin environment characteristics:
- Acidic/ low pH
- Highly concentration of NaCl (salty)
- Some areas lack moisture and is dry
- Some bathed in oily lubricant sebum and antimicrobial
- Skin cills regenerate
Is skin a friendly environment for microorgansisms?
Not friendly
bacterial ____ inhibits growth of pathogens
interference
Microbiota vary by ____ ____
body site
What are normally free of microorganisms?
Internal organs and tissues (Brain, blood, cerebrospinal fluid, muscles)
What are constantly in contact with environment and are colonized by various microbes?
Surface tissues (skin and mucous membranes)
Some microbes are temporarily present on the skin and are typicall unable to
multiply on skin
3 environmental niches of Staphylococcus epidermis
- Dry (forearms, buttocks, hands): less organisms and greater diversity
- Moist (under armpit): more organisms, less diversity
- Sebacceous (forehead, behind ear, back): most organisms,. lowest bacterial diversity
S. Aureus
pathogenic
Staphylococcus epidermis blocks S. Aureus by
- secreting products of fermentation called short chain fatty acids
- binding to pattern recgonition receptor TLR- 2
What is produced by Staphylococcus epidermis to interfere with growth of other bacteria on the skin?
Bacteriocins, Molecules that interfere with quorumn sensing, proteases that degrade adhesions
Fermentation by short fatty acid chains and binding to TLR-2 causes
AMP release which helps with limit inflamation, prevent infection, and promote wound healing
Upper respiratory tract includes:
Nostrils, sinuses, pharynx, and orpharynx
What is most common infection?
Respiratory Tract as it provides entry of a lot of pathogenic microbes
Upper respiratory tract is colonized by
diverse group of bacteria
Lower respiratory tract includes:
larynx below vocal cords, trachea, bronchi, and lungs
True or False: Lung is free of microorganism and sterile
False
Haemophillus spp
Upper respiratory tract
Gram negative rod
Can cause ear infection, pneumonia, meninigitis
Oraphrarynx is most and includes bacteria
diverse
neisseria: gram negative cocci
5 roles of normal flora
- microbial antagonism
- stimulate our immune system
- provide vitamin B12 and K
- Can be common source of infection from opportunistic pathogen
- Help digestion
What is most significant role of normal flora?
Microbial antagonism: normal flora protect host against colonization by pathogen
What is the most stable symbiotic relationship?
Commensalism (host no effect, microorganism benefits)
Commensalism is relationship that exists between __ and ____
human; members of their normal microbiota
Eye bacteria has __ number of bacteria
Small
Predominant bacterium in eye and external ear is
staphylococcus epidermis
External ear is similiar to ___ flora
skin
What bacteria is found in anoxic nature of space between teeth and gums?
Fusobacterium since strict anaerobe and gram negative
Due to anoxic nature of space between teeth and gums, ___ become dominant
Anaerbobes
Why is the mouth great environment for bacteria since….
Moist and provide nutrients
As teeth grow ____ and ___ attach to enamel surfaces
streptococcus parasanguinis and streptococcus mutans
What is the causative agent for dental carriers?
streptococcus mutans
In stomach, most microbes are killed by
acidic contitions (low pH)
Large intestine (colon) microbes
Gut bacteria
Metabolic, immunological and endocrine roles
What site microbe is most densely packed microbial ecosystems on Earth?
Large Intestine (colon)
Ratio of strict anaerboe to faculative anaerobe in large intestine microbes
10 (strict anaerobe) : 1 (faculative anaerobe)
True or False: E coli is not most common bacteria found in large intestine
True since it is faculative anaerobe
Functions of Gut microbiome
- Ferment foods that we cannot digest
- synthesize micronutrients including viatimins
- metabolize dietary toxins and carinogens
- ensure immune system maturation
- protect against enteric pathogens
- converts steroids such as cholesterol and bile acids to other compounds
Primary bile acids are chemically modified by ___ to _____
gut microbes; secondary bile acids
impacts growth of other microbes in the gut
Genitouring Tract includes
kidneys, ureter, urinary bladder
Genitouring Tract are normally free of
microbes
Female gential tract is _____ microbiota that changes due to _____
complex, menstrual cycle
what bacteria predominate in vagina and cervix
acid tolerant lactobacilli
Lactobacilli are important for
protection of female from infection of vagina and cervix but can be killed by antibiotics
____ converts food into calories that we can use which affects our _____
gut microbiota, weight
Functional core microbiome
a group of microbes that provides activities and metabolites required for health and homeostasis of the host
Overweight people have higher concentration of gut bacteria belonging to phylum ____ compared to bacteria belonging to phylum _____
firmicutes (gram +); bacteriodota (strict anaerobe gram -)
Do overweight people have more gram + or gram - bacteria?
Gram +
Metabolome
products these microorganisms secrete
(indiivdual species in gut microbiome to metabolome for overweight people)
Overweight people gut microbiota population ____
changes
Impact of ______ on host metabolism
fermentation end products
Bacteria ferment monomers into ____ which can promote ______
short chain fatty acids, weight gain
Propionte and butgrate prevent
overweight
Fermentation product of acetate cause
overweight
Germ Free (GF) Mice
how we research to study affects of microbes on animal health
don’t have good normal flora
rasied in sterile environment
partipate in fecal microbiome transplant
GF mice can eat more but gain less weight than
beconventional mice
Fecal microbiome transplant
procedure to get rid of clostridium where take feces from healthy donor for normal flora and transfer to patient’s gut
What disrupts the gut microbial community?
Antibiotics
Colonization resistant
aka antagonism
Immunity provided by gut bacteria and is based on competitive exclusion between normal flora and pathogenic
Following antibiotic treatment, people are at a higher risk of
GI tract infections
Ex. C. difficile
Microbiome signals influence _____ at sites _____
immune cell function; distance from the gut
True or false: Gut microbiota affects central nervous system
True
The diet consumed by a person with cardiovascular disease is
red meat and high fat foods
Why is the diet cause cardiovascular disease?
little fiber for gut microbes to produce antiflamatory short chain fatty acids
Cardiovascular disease promots growth of a “meat” eating microbial population that metabolizes ___ and _____ resulting production of _____
L-carnitine, phosphatidylchloline, thimethylamine (TMA)
Microbes are involved in 20% of ____
malignacies (cancer)
Thimethylamine (TMA)
absorbs into blooodstream and travels to liver causing cardiovasciular disease (astherosclerosis)
Helicobacter
stomach cancer and disregulate host cell cycling and carcinogen
Bacteria involved in metastasis of tumors to
distant sites
Lactobacillus acidophilus
fed to cattle to carry less E. Coli
Helps make beef meet quality standards
Probiotics
Live microorggnaisms when admistered in adequate amounts which help with health benefit to host
Loss of microbiome diversty leads to
dysbiosis and variety of diseases that involve inflamation
Many cancers linked to microorganisms are driven by
inflamatory state associated with dysbiosis/ imbalance
E. Coli: 0157: H7 is
pathogenic!
Bacteriocins
toxic peptides preoduced by gram positive bacteria that target closely related species
