BIOL 206 Janes Exam #4

The body harbors about ______________ (number) _______________ and ________________ microorganisms (types)

The body harbors about 10^14 prokaryotic and eukaryotic microorganisms

Microorganisms have three types of environmental contact with our bodies. List and describe these three

1) implant - stable residence on the host

2) transient - passes through the body

3) invasion - pathogens invade and harm the host

The body is a _____________________ (favorable/unfavorable) habitat for an abundance of microorganisms. Why? (5)

The body is a favorable habitat for microorganisms because of a stable temperature, a stable pH, nutrients, water, and large surface area

Why/how are we able to maintain favorable conditions for microorganisms? (3)

We keep our body in homeostasis, provide nutrients by eating, and give a surface area to grow on

The microbiome project of 2014 determined what?

Normal biodiversity promotes health while dysbiosis promotes disease

The hygiene hypothesis states what two things

1) antibiotics and lifestyle that lower microbial exposure predisposes people to autoimmune disease

2) antibiotics disturb microbiota and thus, the co evolutionary relationship between our immune system and the symbionts we host

Microbiota can modify its microhabitat by doing what five things?

1) altering the environmental pH

2) altering oxygen tension

3) excreting chemicals

4) creating chemical barriers

5) creating physical barriers

What 4 chemicals are excreted by microorganisms which serve to modify their microhabitat in the human body?

Acids, alcohols, antibiotics, bacteriocins

Lactobacillus, often found in the ________________ (body part), affect pH and oxygen tension in what way?

Lactobacillus found in the vagina lower the pH and lower oxygen tension

What are bacteriocins?

they are chemicals excreted by microbiota which are similar to antibiotics, but are meant for closely related species

Normal flora benefits humans in what three ways?

It provides protection, nutrition, and promotes health

Normal flora is a complex mixture of what types of microorganisms?

prokaryotes, eukaryotes, viruses

T/F: the normal flora in every individual is identical

False: normal flora DIFFERS in QUALITY and QUANTITY between individuals

The fluctuation of the flora in a person is ____________________ (volatile/stable)

relatively stable

Fluctuation of the flora occurs due to what eight factors?

1) antibiotics/drugs

2) environment/hygiene

3) immune system

4) diet/nutrition

5) stress

6) hormones

7) aging

8) illness/diarrhea

The normal flora affects what? (6)

1) weight

2) anxiety

3) depression

4) immune function

5) sleep

6) ability to learn/concentrate

How can a good diet and drinking enough water be beneficial to our microbiota?

Good foods and water feeds our gut bacteria to prevent issues caused by dysbiosis

Define dysbiosis

microbial imbalance

How do we know that normal flora affects so many things?

Research on lab rats: scientists took a strain of skinny rats and of obese rats and crossed them and the offspring were the same due to a transfer of bacteria

Viruses have been found in ________________ and on _________________ proving that they are a part of our normal flora

in feces and on mucosal surfaces

T/F: viral genes in our normal flora become stable over time

true

The variability of bacteriophages in our gut is _________ % proving that we have a _______________ relationship

Less than 5%; symbiotic

_______ % of viruses have never been reported

Over 80%

Viruses carry genes for what two things which influence bacterial metabolism?

Viruses carry genes for metabolism of carbon, hydrogen, oxygen and for amino acid synthesis in bacteria

T/F: viruses in the microbiome influence bacterial metabolism

true

T/F: viruses contain genes found in our eukaryotic cells

true

What common intestinal disease is a result of dysbiosis?

Irritable Bowel Disease (IBD)

Bacterial diversity and bacteriophage numbers in our microbiota are _________________ related (directly/inversely) thus a decrease in bacterial diversity causes a _____________ in bacteriophages

Inversely related; decreased bacterial diversity causes an increase in bacteriophages

Prior to a 2015 study, babies in the womb were believed to be in a ____________________ (sterile/well colonized) environment. Now, however, scientists know what?

Babies were believe to be in a sterile environment in the womb until a 2015 study proved that the placenta/cord blood/womb all contain bacteria which is colonized before birth

T/F: the gut of a newborn is sterile because the womb is sterile

False: because the womb has bacteria, a newborn's gut is well-populated with bacteria

T/F: after birth, the colonization of bacteria obtained by the baby in the womb ceases and becomes a constant microbiome with little fluctuation

False: after birth, the bacteria obtained by baby INCREASES in colonization thus increasing the microbiota in the baby

The normal flora of a bottle fed baby is a ______________ (pure/mixed) population consisting of coliform of what type(s) of bacteria? (+ what other?)

Mixed population: E coli, Enterobacter sp, Klebsiella sp

Other important bacteria: lactobacillus, enteric streptococcus, staphylococcus

T/F: bacteria have a role in the development of the gut of a newborn

true

Describe the normal flora of a breast fed baby

It starts off with E coli and streptococci but shortly becomes primarily bifidobacterium and lactobacillus sp

Breastmilk produces over 200 _____________ and are described as _______________ and ______________ (in the slides)

Breastmilk produces over 200 different oligosaccharides (short chains of sugars) and are described as being complex and dynamic

T/F: formulas cannot imitate breast milk as breast milk is a very complex mixture that remains constant over time

False: formulas cannot imitate breast milk as breast milk is a very complex mixture that CHANGES over time

Research has identified __ (number) oligosaccharides in formulas

2

List the seven benefits of bifidobacterium and lactobacillus in adults and babies

1) maintain normal intestinal balance

2) improve lactose tolerance

3) antitumorigenic activity (anticancer)

4) reduce serum cholesterol levels

5) promotes calcium absorption

6) synthesis of B complex vitamins

7) reduce or prevent the excretion of rotaviruses

Sick gut syndrome is termed ______________

rotavirus

T/F: lactobacillus, when found in the gut, is considered highly pathogenic and must be treated with a high dose of lactulose antibiotics

False: lactobacillus is highly BENEFICIAL to the human microbiome

Oral administration of host-specific living microorganisms is termed _____________ and is used to do what two things

Oral administration of host-specific living microorganisms is termed probiotics and is used to

1. promote health

2. reestablish the natural balance of microbiota

In what two instances are probiotics commonly used?

After illness or after antibiotics

What are prebiotics?

non digestible dietary fiber which promotes the growth of probiotics -- like food for your probiotics

example: inulin

List the four features of probiotic microorganisms which are beneficial to humans

1) they maintain desirable microbial community

2) stabilize gut barriers

3) produce of inhibitory substances

4) stimulate the immune response

List the attributes of probiotic bacteria (5)

1) nonpathogenic

2) no toxin produced

3) effective

4) easily cultured

5) withstand acid and bile

T/F: most probiotic bacterias sold in capsule form have a high tolerance to withstand acid and bile thus allowing them to go through the acidic stomach and into the large intestine

False: most probiotic capsules CANNOT withstand acid and bile

List the industry standards of probiotics (3)

1) easy to produce in high numbers

2) no off flavours

3) must retain function though the manufacturing process, transport, and storage

Breastmilk varies in _________ and ___________ of oligosaccharides produced

Number and content

List the foods which provide good sources of prebiotics (12)

onions, garlic, leeks, apples, bananas, cocoa (dark chocolate), flaxseed, bran, oats, leafy greens, sauerkraut, kefir

List three common prebiotics

Inulin, pectin, fiber

Sauerkraut and kefir are good sources of what type of probiotic?

Lactobacillus

List the two species of bacteria most commonly found in different areas of the body

Staphylococcus and streptococcus

Each person has a unique normal flora but...

there are common patterns seen in many individuals

T/F: yeasts are a normal part of the microbiome

true

The skin has mostly gram _________ bacteria and little to no gram _________ bacteria. The skin also has ___________

The skin has mostly gram positive bacteria and little to no gram negative bacteria. The skin also has yeasts

Why is gram ___________ bacteria so prevalent on the skin?

Gram positive bacteria tolerate higher salt levels than gram negative bacteria which is necessary because sweat tends to be salty thus making the skin environment salty

T/F: all areas of the body have the same level of microbial diversity throughout

False: some areas have MORE or LESS microbial diversity than others

Which part of the body has the most diverse microbiome? List the microbiomes seen in this body part

The skin has the most diverse microbiome consisting of 3 distinct microbiomes: moist, oily, and dry

T/F: there are different bacteria on different parts of the skin

true

The skin ________________ (is/is not) a favorable environment for most microorganisms. Why? (4)

The skin is not a favorable environment because:

1) periodic drying

2) slightly acidic pH

3) sweat/high salt

4) lysozyme

The skin has a pH of __________ which is slightly ___________ (acidic/basic)

The skin has a pH of 6.5 which is slightly acidic

Why does high salt on the skin present an issue to many microorganisms?

High salt levels cause osmotic stress

Why is the skin a slightly acidic environment?

The bacteria which reside on the skin release acids preventing pathogenic acidophobic bacteria from growing

What is lysozyme and why is it an issue for bacteria?

Lysozyme is an enzyme in all body secretions and breaks the NAG and NAM linkages in peptidoglycan of the bacterial cell wall thus destroying the cell wall

P. acnes is found ______________ and functions to do what?

P. acnes is found on the skin and functions to produce protective thiopeptides which block other gram positive bacteria

P. acnes likes to eat _______________ and therefore is good for breaking down _______________

P. acnes likes to eat oils and therefore is good for breaking down complex lipids secreted by the oil glands

During puberty, there is increased oil production on the skin which is metabolized into ________________________ and causes _______________________ which leads to acne

During puberty, there is increased oil production on the skin which is metabolized into volatile fatty acids and causes increased skin inflammation which leads to acne

How can acne be treated and why?

Acne can be treated using skin probiotics because they increase the number of bacteria on the skin which like to eat up oils thus getting rid of the cause of skin inflammation/acne

P. acne is __________________ (type of O2 loving/hating). How does this factor into acne?

P. acne is aerotolerant and so when oil clogs a pore, the bacteria is trapped beneath and thrives in the absence of O2

Describe the historical view of the microbiome of the eye

Originally believed to be very limited flora in the eye that was fastidious and nonpathogenic because blinking, tears, and lysozyme was thought to clear out all of the bacteria

• nonpathogenic Corynebacteria + Staphylococcus epidermidis

Explain the current view of the microbiome of the eye

All exposed mucosal surfaces are populated with bacteria including the eye

T/F: there are very limited different species of bacteria on the eye

False: there is a HUGE VARIATION of bacteria on the eye

List the two things that happen during an eye infection/are indicators of an infection

1) decrease in bacterial diversity

2) increase in Pseudomonas sp

Describe the appearance of Pseudomonas sp during an eye infection

It turns green when given the right nutrients to thrive

The microbiome of the outer ear is similar to what other part of the body? In what way are they similar?

The skin; both contain gram positive staphylococcus and streptococcus

Swimmer's ear occurs in what part of the ear (outer/middle/inner) and is caused by what bacteria?

Swimmers ear occurs in the middle ear and is caused by Pseudomonas aeruginosa

Give the concoction that is effective for treating swimmers ear and why each ingredient is effective

Isopropyl alcohol (dries fluid), vinegar (changes the pH), H2O2 (kills bacteria)

Middle ear infections are caused by an increase in what two things? Which one causes pain and why?

Caused by increase in bacteria and fluids; increased fluid levels cause pressure and therefore pain

You're diagnosed with a middle ear infection and given a course of antibiotics to kill the bacteria. Several days into the course of antibiotics, you are still in pain. Why?

Antibiotics kill the bacteria but do not reduce excess fluid levels which are what cause the pain

What anatomical change occurs as a person develops that results in protection for middle ear infections?

As a child develops into an adult, their Eustachian tube bends protecting the ear from bacteria in the throat/nasopharynx

Middle ear infections are commonly caused by bacteria from which part of the body?

The nasopharynx - enters Eustachian tube

Describe the microbiome of the mouth and where in the mouth it is found (3)

1) large population

2) many different microbiomes

3) found on the roof, teeth, gums, tongue

How do microorganisms in the mouth keep from getting swallowed with food/mechanical removal?

they adhere to the surfaces of the mouth

Saliva has ___________ bacteria per mL and include what four species of bacteria and what other microbes?

Salive has 10^9 bacteria per mL and includes streptococci, staphylococci, neisseria, lactobacilli, fungi, and protozoans

T/F: candidiasis is found in the mouth as a part of the normal flora

true, but kept at low levels

What mechanism prevents the overgrowth of candidiasis? If there is overgrowth, it is termed ____________ when in the mouth and is characterized by a ________________ tongue

Bacteria of the normal flora secrete acids which keep the candidiasis from overgrowing. If it does overgrow in the mouth, it is called thrush and is characterized by a white tongue.

T/F: the structure of the microbiome of the mouth is random and sporadic due to the high levels of saliva circulating throughout the mouth

False: the structure of the microbiome is NOT RANDOM and is in LAYERS

___________________ forms the first layer of the microbiome of the mouth

streptococcus sp

Describe the formation of a biofilm

a community of bacteria excrete a sticky matrix for attachment and persistence

The formation of a biofilm aids in bacteria being able to resist what two things? It also increases what

1) antibiotics

2) mechanical removal (such as swallowing)

Also increases pathogenesis

T/F: dental cavities are essentially biofilm in the mouth

False: dental PLAQUE is essentially biofilm in the mouth

Streptococcus sp can cause several diseases of the mouth including what 4 diseases

Dental plaque, dental caries, gingivitis, periodontal disease

T/F: studies suggest that poor dental health/the presence of biofilms in the mouth link to lung cancers

False: studies suggest that poor dental health/the presence of biofilms in the mouth link to HEART DISEASE

The formation of biofilms make bacteria ____________________ resistant making it difficult to treat an infection

antibiotic

Biofilms are relatively ______________ (impenetrable/penetrable) by antibiotics

impenetrable

List the protective factors that biofilms have that subdue the effectiveness of antibiotics (6)

1) antibiotics may not be able to penetrate the biofilm

2) antibiotics degrade at contact with the biofilm

3) antibiotics are absorbed onto the matrix of the biofilm

4) the microenvironment is changed

5) anaerobic niches allow for the biofilm to thrive

6) acidic wastes prevent antibiotics from being effective

Biofilms thwart the immune response in what two ways. Which way may have a negative impact on the heart?

1) phagocytes are repelled

2) inflammatory response which damages host cells - may negatively impact the heart

In biofilms, bacteria stick to the surface using ____________ and a ________________ which make them hard to remove

In biofilms, bacteria stick to the surface using fimbriae and a polysaccharide which make them hard to remove

In biofilms, bacteria talk to each other through __________________ termed _________________. Explain this process.

Talk to each other through chemical messengers - one cell excretes a chemical that tells another cell what to do - termed quorum sensing

The flora of the upper respiratory tract is similar to what other body part? In what way?

Similar to the mouth - contains streptococci