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Oral Microbiology > Lecture 01: Ecology Handout > Flashcards

Lecture 01: Ecology Handout Flashcards

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Biology 101 flashcards
1
Q

new and old ways of detecting a bacterial species

A

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

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2
Q

how many species are in the oral cavity?

A

300+ and more than half have not been cultivated

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3
Q

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

A

100-200

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4
Q

the mouth is an ____ system

A

open

transient vs true residents in the cavity that grow

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5
Q
  • 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
A

human micro biome project

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6
Q

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

A

bacteria

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7
Q

what has more DNA variety… human cells or bacteria

A

bacteria

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8
Q

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

A

degree of early contact

  • hygiene hypothesis
  • dont kiss babies or will speed S. mutans…
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9
Q

study of the interrelationships of organisms and their environment

A

ecology

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10
Q

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

A

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

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11
Q

do niches change over time?

A

yes

  • organisms are acquired
  • teeth erupt/lost
  • pockets/injuries occur
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12
Q

biofilm thickness ____ over time

if its surfaces are cleaned, ______ occurs

A
  • increased

- succesion

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13
Q

soft tissue surfaces which bacteria adhere to

A

sulcus, tongue, mucosa, gingiva

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14
Q

hard suffices that bacteria adhere to

A

“dental plaque”

-supra- and sub gingival hard surfaces

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15
Q

bacteria that float in water

A

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

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16
Q

many of the bacteria that cause dental problems are ____

A

sessile (attached to surface in biofilms)

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17
Q

biofilms are made up of what?

A
  • adherent microorganisms

- extracellular matrix in aqueous environment

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18
Q

sticky material that holds the biofilm together

A

extracellular matrix

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19
Q

biofilm life cycle

A
  • attachement
  • growth to mature biofilm community
  • detachment of cells to seed new biofilm formation
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20
Q

biofilms are often formed by single/multiple species of bactera

A

multiple

may also be fungi, algae, and protazoa

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21
Q

once bacteria adhere to a surface, they _____

A

change

22
Q

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

A
  • complex

- interactive communities (turn on different set of genes)

23
Q

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

A
  • bacteria detect surfaces
  • bacteria detect each other (quorum sensing)
  • signals pass btw them
24
Q

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

A
  • slow
  • antibiotics
  • host defenses
  • mechanical disruption
25
Q

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

A

1000X

26
Q

3 primary mechanisms for bioflim antimicrobial resistance

A
  • slowing of diffusion
  • “persister cells” that repopulate biofilm
  • close proximity and exchange of resistance genes
27
Q

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

A

yes

28
Q

host sites for adherance

A
  • host surfaces (receptor molecules)
  • direct bacterial interactions
  • extracellular matrix
29
Q

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

A

salivary binding

30
Q

what are the O2 %’s in :

  • air
  • closed mouth
  • perio pocket
  • supragingival plaque
A

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

31
Q

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

A

oxidation-reduction potential (Eh)

  • positive Eh aerobes (high O2)
  • negative Eh anaerobes (low O2)
32
Q

require low levels of O2

A

microaerophilic

33
Q

have anaerobic metabolism but tolerate the presence of O2

A

aerotolerant anaerobes

34
Q

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

A

oxygen toxicity

35
Q

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

A
  • superoxidase dismutase
  • catalse
  • peroxidases

(in their absence, oxygen can damage the cells)

36
Q

superoxide dismutase, catalse, and peroxidase do what?

A

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

37
Q

older plaque has a higher/lower Eh

A

lower

38
Q

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

A

fusobacterium

39
Q

negative log of the hydrogen concentration

A

pH

40
Q

how to affect pH: directly or indirectly

A

directly: carbonated soft drink
indirectly: bacterial fermentation of sugars)

41
Q

pH normally ranges from what to what?

A

5-7.5

42
Q

low pH inhibits most oral species except for what?

A

acid tolerant (acid uric) strep and lactobacilli

43
Q

exogenous (injested) nutrient sources are important for ____ species

A

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
44
Q

two nutrient sources for biofilms in the oral cavity

A
  • exogenous (injested)

- endogenous (saliva, shed host cells, GCF)

45
Q

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

A
  • plaque
  • caries

*bc you need carbs to have caries

46
Q

what are the three host inhibitory factors?

A
  • antibodies
  • innate immunity
  • saliva
47
Q

what are the two antibodies associated with host inhibitory factors

A

-sIgA (in saliva, prevents adhesion)

IgA (in GCF, stops invasion of soft tissues)

48
Q

most salivary proteins are what two things?

A
  • alpha amylase (digests starches and binds bacteria)

- mucins (lubricants)

49
Q

what are some of the salivary defenses (minor proteins)

A
  • salivary lysozyme
  • salivary lactoferin and transferin
  • sialoperoxidase system
  • antimicrobial peptides
  • acidic proline
50
Q

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

A

lactic acid

51
Q

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

A

ENHANCES THE GROWTH of AA

52
Q

what are two examples of microbial inhibitory factors

A
  • bacteriocins

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

Oral Microbiology (3 decks)

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