Chapter 33

Question 1

Microbiome

Answer 1

community of microorganisms that exists in an environment

Question 2

Microbiota

Answer 2

all the microorganisms that live in a microbiome

Question 3

Holobionts

Answer 3

hosts and microbes live together in symbiosis and evolve together

Question 4

Commensals

Answer 4

microorganisms in and on human body
that do not harm health. But the situation is complex.

Question 5

what was the NIH human microbiome project

Answer 5

characterize the human microbiome to understand its role in health and disease

Question 6

In the microbiome database- how many unknowns are there?

Answer 6

> 70% of these genomes lack cultured representatives
40% of genes lack function assignments

Question 7

Normal microbiota

Answer 7

microorganisms that establish permanent
colonies inside or on the body without producing disease
ex: Staphylococcus on epidermis and mucus membranes;
Escherichia coli in colon

Question 8

Transient microbiota

Answer 8

are microbes that are present for various periods and then disappear.
* Although these types of organisms may colonize a host and reproduce briefly, the defenses of the human body do not allow them to become permanent.

Question 9

what are the benefits of the normal microbiota? (5)

Answer 9

1. Synthesize and excrete vitamins
   Vitamin K and Vitamin B12
2. Prevent colonization by pathogens
   - competing for attachment sites or for essential nutrients
3. May antagonize other bacteria
   - the production of substances which inhibit or kill non-indigenous species (nonspecific fatty acids, peroxides, bacteriocins).
4. Stimulate the development of certain tissues
   i.e., intestines, certain lymphatic tissues, capillary density
5. Stimulate the production of cross-reactive antibodies.
   Low levels of antibodies produced against components of the normal flora are known to cross react with certain related pathogens, and thereby prevent infection or
   invasion.

Question 10

how does microbial antagonism work?

Answer 10

prevent pathogens from causing an
infection by competing for nutrition.
* Affecting condition as
pH or available oxygen
* Decreased oxygen slows
growth of facultative
anaerobic pathogens

Question 11

what is interference competition?

Answer 11

It’s a form of microbial antagonism where it Produce substances harmful for invading
organisms
Bacteroidales produce bacteriocins

Question 12

what age do you get a stable microbiota?

Answer 12

3

Question 13

Bifidobacteria

Answer 13

Transport polymeric sugars (oligosaccharides) found in human breast milk directly across their plasma membrane
- Fermentation of these sugars provides
the infant with calories and lowers the
gut pH, limiting growth of pathogens

Question 14

what are the 6 main types of microbes found on human skin, the intestinal tract, and other mucosal surfaces

Answer 14

*Actinobacteriota
* Bacteroidetes
* Firmicutes
* Fusobacteriota
* Proteobacteria
* Verrucomicrobiota
including fungi, archaea, and some viruses

Question 15

what are normally free of micro organisms?

Answer 15

internal organs (brain, blood, cerebrospinal fluid, muscles)

Question 16

what is the skin environment?

Answer 16

*Slightly acidic pH.
* High concentration of NaCl.
* Some areas lack moisture.
* Some bathed in oily lubricant sebum and antimicrobial
peptides.

Question 17

what are the primary skin micro organisms?

Answer 17

Propionibacterium acnes, Staphylococcus
epidermidis and Staphylococcus aureus

Question 18

what is significant about hair on the skin microbiome?

Answer 18

Microorganisms and mites (arthropods) colonize hair follicles and glands
Commensal fungus, Malassezia spp. grow as branching hyphae and individual cells
Odors produced by
microorganisms

Question 19

What are the intrinsic factors of the skin microbiome?

Answer 19

Age, sex, hormones, ethnicity

Question 20

What are extrinsic factors of the skin microbiome?

Answer 20

Hygiene, skin products, UV exposure,

Question 21

What do Keratinocytes and dermal appendages do?

Answer 21

elease antimicrobial peptides and proteins
(AMPs), which provide defense against
pathogenic microbes on the skin

Question 22

Staphylococcus epidermidis

Answer 22

Most common coccus that colonizes the skin
Key component of healthy skin. Generally non-pathogenic
Modulate keratinocyte gene expression stimulating antimicrobial peptide release
Uses bacterial interference to kill pathogens

Question 23

what are the microbes found in eye and ear?

Answer 23

eye- Staphylococcus epidermidis
ear- nonpathogenic staphylococci and
Corynebacterium spp.

Question 24

what is microbial dysbiosis in the lungs linked to?

Answer 24

cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) and infection

Question 25

what are significant micro organisms of the oral microbe?

Answer 25

Streptococcus parasanguinis and S. mutans attach to enamel surfaces; S. salivarius attaches inside the cheeks and gum epithelial surfaces and colonizes the saliva.

Question 26

diseases associated with the oral microbiome?

Answer 26

Alzheimer's, cardiovascular disease, CF, cancer, diabetes, periodontitis, arthritis

Question 27

what micro organisms are in the Distal portions of urethra?

Answer 27

S. epidermidis, Enterococcus faecalis, and Corynebacterium spp. Dysbiosis linked to UTI

Question 27

what part of the GI tract is germ free

Answer 27

Kidneys, ureter, and bladder

Question 28

What are the functions of the gut microbiome?

Answer 28

*Carbohydrate fermentation and absorption - Digest starch, plant fiber, pectin into SCFAs (short chain fatty acids: acetic acid, propionic acid, butyric acid). Digest proteins like collagen, elastin. *Repression of pathogenic microbial growth - Competition for nutrition, attachment. -Produce bacteriocins, Lactic acid. *Metabolic function -HCA (heterocyclic amines): reducing the mutagenic risks *Preventing inflammatory bowel disease -SCFAs prevent IBD *Preventing opportunistic infections -Clostridium difficile

Question 29

What is the stomach microbiome like?

Answer 29

Most die from acidic conditions Streptococcus, Staphylococcus, Lactobacillus, Peptostreptococcus spp., and yeasts such as Candida spp. can survive

Question 30

Helicobacter pylori

Answer 30

pathogen causing ulcers

Question 31

what are the 2 predominate phyla of the gut microbiome

Answer 31

Firmicutes and Bacteroidetes, which comprise 80-90% of the speciesfound

Question 32

what is metabolic endotoxemia

Answer 32

at least three of the following: * Large waist circumference. * High blood triglyceride level. * High blood pressure. * Elevated low-density lipoprotein. * High fasting blood glucose levels LPS in blood of obese people is 2-3x higher

Question 33

What are the 3 ways the microbiome affects the CNS?

Answer 33

* Microbiome impacts the immune system. * Direct pathway from gut to brain through nerves in G I tract, which transmit signals to the brain via the vagus nerve. * Soluble microbial products cross the blood brain barrier.

Question 34

Do overweight people have more Firmicutes or Bacteroidetes? and an increase in what?

Answer 34

Firmicutes increase in Short Chain Fatty Acids which are fermented from bacteria

Question 35

metabolome

Answer 35

products gut microorganisms secrete

Question 36

What is the energy source for colonocytes

Answer 36

Butyrate

Question 37

What is the diet of someone with Cardiovascular Disease like?

Answer 37

- Little fiber for gut microbes to produce anti-inflammatory SCFAs. - Red meat Promotes growth of a “meat-eating” microbial population that metabolizes L-carnitine and phosphatidylcholine resulting in the production of trimethylamine (TMA). * TMA is absorbed into the bloodstream, travels to the liver where it is enzymatically oxidized by liver cells to trimethylamine N-oxide. *Acceleration of atherosclerosis (build up of fat in arteries).

Question 38

The microbiome and CVD?

Answer 38

- Less carnitine and more complex fiber results in more Bacteriodetes - Probiotics (Lactobacilli) are associated with weight loss but not lowering of TMA meat and eggs= TMA Blood levels of TMA are strongly linked to vascular plague formation and CVD

Question 39

what are the ways microbes can cause cancer?

Answer 39

*Certain viruses cause host cells to become cancerous. Ex: HPV -Alter the host cell cycle and prevent host cells from repairing DNA damage *Carcinogen-producing strains of Bacteroides fragilis *Helicobacter pylori dysregulate host cell cycling. - Bacteria can be involved in metastasis of tumors to distant sites

Question 39

Probiotics

Answer 39

application of life microbial culture * Typically lactic acid producing bacteria ingested to aid digestion and protect intestine from pathogens (kombucha, kimchi, etc.)

Question 39

Prebiotics

Answer 39

refer to chemicals that induce the growth and/or activity of commensal microorganisms

Question 40

Synbiotics

Answer 40

foods or supplements that include both a prebiotic and a probiotic