#1 Ecology of the mouth

Question 1

new and old ways of detecting a bacterial species

Answer 1

old: microscopy and cultivationnew: 16S sequencing, rDNA gene alignments, and phylogenic trees

Question 2

how many species are in the oral cavity?

Answer 2

300+ and more than half have not been cultivated

Question 3

how many species does a single human harbor in their mouth?

Answer 3

100-200

Question 4

the mouth is an ____ system

Answer 4

opentransient vs true residents in the cavity that grow

Question 5

-determine whether ppl share a core micro biome-understanding if changes in micro biome are correlated with changes in human health-new technology-addressing ethics, legal, and social aspects made by research

Answer 5

human micro biome project

Question 6

which do we have more of…. human cells or bacteria

Answer 6

bacteria

Question 7

what has more DNA variety… human cells or bacteria

Answer 7

bacteria

Question 8

how is it thought that we get our human oral micro biome?

Answer 8

degree of early contact-hygiene hypothesis-dont kiss babies or will speed S. mutans…

Question 9

study of the interrelationships of organisms and their environment

Answer 9

ecology

Question 10

specific combo of conditions that are necessary for the survival of a particular organism

Answer 10

niche(parameters are physical, chemical, and biological)(different oral sites harbor different bacterial species)

Question 11

do niches change over time?

Answer 11

yes-organisms are acquired-teeth erupt/lost-pockets/injuries occur

Question 12

biofilm thickness ____ over time if its surfaces are cleaned, ______ occurs

Answer 12

-increased-succesion

Question 13

soft tissue surfaces which bacteria adhere to

Answer 13

sulcus, tongue, mucosa, gingiva

Question 14

hard suffices that bacteria adhere to

Answer 14

“dental plaque”-supra- and sub gingival hard surfaces

Question 15

bacteria that float in water

Answer 15

planktonic (most bacteria in the mouth ARE NOT this bc they would be swallowed)

Question 16

many of the bacteria that cause dental problems are ____

Answer 16

sessile (attached to surface in biofilms)

Question 17

biofilms are made up of what?

Answer 17

-adherent microorganisms-extracellular matrix in aqueous environment

Question 18

sticky material that holds the biofilm together

Answer 18

extracellular matrix

Question 19

biofilm life cycle

Answer 19

-attachement-growth to mature biofilm community-detachment of cells to seed new biofilm formation

Question 20

biofilms are often formed by single/multiple species of bactera

Answer 20

multiplemay also be fungi, algae, and protazoa

Question 21

once bacteria adhere to a surface, they _____

Answer 21

change

Question 22

biofilm bacteria behavior is much more _____ than suspended cell behavior bc they live in _____ ____

Answer 22

-complex-interactive communities (turn on different set of genes)

Question 23

when are three cases when biofilm-adaptive genes are turned on?

Answer 23

-bacteria detect surfaces-bacteria detect each other (quorum sensing)-signals pass btw them

Question 24

biofilms are stage, ___-growing communitites that are highly resistant to ______, _____ and ______

Answer 24

-slow-antibiotics-host defenses-mechanical disruption

Question 25

antibiotic doses that kill suspended cells need to be inc as much as ______ to kill biofilm

Answer 25

1000X

Question 26

3 primary mechanisms for bioflim antimicrobial resistance

Answer 26

-slowing of diffusion-"persister cells" that repopulate biofilm-close proximity and exchange of resistance genes

Question 27

does prevention of oral bioflims have an effect on preventing invasive species?

Answer 27

yes

Question 28

host sites for adherance

Answer 28

-host surfaces (receptor molecules)-direct bacterial interactions-extracellular matrix

Question 29

promotes adherence by providing binding sites or inhibits by agglutinating and clearing antibodies and other similar things

Answer 29

salivary binding

Question 30

what are the O2 %'s in :-air-closed mouth-perio pocket-supragingival plaque

Answer 30

air: 21%closed mouth: 12-14%perio pocket: 1-2%supragingival plaque: 1-20% (depends on plaque age)

Question 31

electric potetial or tendency to oxidize or reduce (oxygen level)

Answer 31

oxidation-reduction potential (Eh)-positive Eh aerobes (high O2)-negative Eh anaerobes (low O2)

Question 32

require low levels of O2

Answer 32

microaerophilic

Question 33

have anaerobic metabolism but tolerate the presence of O2

Answer 33

aerotolerant anaerobes

Question 34

results in oxidation of membrane lipids and destruction of cells integrity and causes oxidation of sulfhydryl groups in enzymes resulting in cross-linking and inactivity

Answer 34

oxygen toxicity

Question 35

the sensitivity of anaerobes to oxygen is due to the GENETIC inability to make enzymes such as ___, ____, and ____

Answer 35

-superoxidase dismutase-catalse-peroxidases(in their absence, oxygen can damage the cells)

Question 36

superoxide dismutase, catalse, and peroxidase do what?

Answer 36

detoxify O2 radicals that are generated by living systems in the presence of )2

Question 37

older plaque has a higher/lower Eh

Answer 37

lower

Question 38

this bacteria scavenges O2 and help to provide and anaerobic environment for other species

Answer 38

fusobacterium

Question 39

negative log of the hydrogen concentration

Answer 39

pH

Question 40

how to affect pH: directly or indirectly

Answer 40

directly: carbonated soft drinkindirectly: bacterial fermentation of sugars)

Question 41

pH normally ranges from what to what?

Answer 41

5-7.5

Question 42

low pH inhibits most oral species except for what?

Answer 42

acid tolerant (acid uric) strep and lactobacilli

Question 43

exogenous (injested) nutrient sources are important for ____ species

Answer 43

supra gingival species(frequency is important)-low molecular weight, soluble carbs and amino acids readily taken up by bacteria-starches and proteins must be retained for bacterial digestion to occur

Question 44

two nutrient sources for biofilms in the oral cavity

Answer 44

-exogenous (injested)-endogenous (saliva, shed host cells, GCF)

Question 45

endogenous nutrients sufficient for _____ but not for _____ (why)

Answer 45

-plaque-caries*bc you need carbs to have caries

Question 46

what are the three host inhibitory factors?

Answer 46

-antibodies-innate immunity-saliva

Question 47

what are the two antibodies associated with host inhibitory factors

Answer 47

-sIgA (in saliva, prevents adhesion)IgA (in GCF, stops invasion of soft tissues)

Question 48

most salivary proteins are what two things?

Answer 48

-alpha amylase (digests starches and binds bacteria)-mucins (lubricants)

Question 49

what are some of the salivary defenses (minor proteins)

Answer 49

-salivary lysozyme-salivary lactoferin and transferin-sialoperoxidase system-antimicrobial peptides-acidic proline

Question 50

produced by metabolism of sugars by streps and is required by Veillonella

Answer 50

lactic acid

Question 51

carbon dioxide is generated by a number of organisms and does what?

Answer 51

ENHANCES THE GROWTH of AA

Question 52

what are two examples of microbial inhibitory factors

Answer 52

-bacteriocins-colonizaiton resistance (established organism occupies the niche preventing new strains)