Week 3 & 4 review

Question 1

Microbe

Answer 1

all types of microscopic organisms

Question 2

bacterium/bacteria

Answer 2

smallest, simplest living organisms

Question 3

Cell envelope

Answer 3

a complex, multilayered structure that protects the microorganism from external environment

Question 4

Gram staining

Answer 4

classifies bacteria as gram positive or negative

Question 5

Gram positive

Answer 5

single, thick, multilayered, mesh-like, wall composed of peptidoglycan, thick layer lies above cytoplasmic membrane that faces the interior of the cell
appears purple

Question 6

Gram negative

Answer 6

two membranes:
1) outer membrane faces external environment, composed of proteins and lipoplysacchrides (endotoxin)
2) between outer and cytoplasm, is a thin cell wall compared of peptiglycan - does not absorb purple appears red

Question 7

Biofilm

Answer 7

complex microbial community, embedded within an extracellular self-protective matrix, that adheres to a living or nonliving surface

Question 8

oral biofilm

Answer 8

3D community embedded in a protective matrix that consists of microbial metabolic products or host components

Question 9

commensal bacteria

Answer 9

part of normal flora, symbiotic relationship with host

Question 10

dysbiosis

Answer 10

microbial imbalance in body

Question 11

vertical transmission

Answer 11

saliva form parent to child (different generations)

Question 12

horizontal transmission

Answer 12

sharing saliva from same generation

Question 13

Acquired salivary pellicle

Answer 13

within seconds, salivary film forms composed of salivary glycoproteins and antibodies

Question 14

coaggregation

Answer 14

process with genetically distinct bacteria become attached to another

Question 15

extracellular protective matrix

Answer 15

once firmly attached, microbes will secrete an enveloping protective substance

Question 16

Microbial blooms

Answer 16

periods when specific groups will grow rapidly; fast; begin to grow away from tooth

Question 17

Mushroom-shaped micro colonies

Answer 17

microbes cluster together that are attached to tooth surface at a narrow base - results in complex collection of different microbes linked together

Question 18

fluid channels

Answer 18

penetrate the ECM, direct fluids around biofilm, brining nutrients and oxygen, and carry waste away.

Question 19

quorum sensing

Answer 19

communication occurs when biofilm release and sense small proteins (signalling proteins)

Question 20

tooth-associated plaque biofilms

Answer 20

bacteria attached to tooth surface
examples: Streptococcus mitis, S. Sanguis, Actinomyces viscosus
- Cocci and rods dominate tooth - associated plaque biofilms

Question 21

tissue-associated plaque biofilms

Answer 21

bacteria that adhere to the epithelium
example: spirochetes and flagellated and gram negative cocci and rods
- Streptococcus oralis, S. intermedius, porphyromonas gingivalis, pevotella intermedia, tannerella forsythia, fusobacterium nucleatum

Question 22

unattached bacteria

Answer 22

periodontal pocket also contains free-floating unattached bacteria

Question 23

Non-specific plaque hypothesis

Answer 23

the accumulation of bacterial biofilms lead to periodontal disease (historical)

Question 24

specific plaque hypothesis

Answer 24

the specific pathogenic bacteria and their products in the biofilm lead to periodontal disease (historical)
- Orange and red complexes - major etiologic agents of periodontal disease
- Yellow, green, blue, and purple complexes - compatible with gingival health

Question 25

ecological plaque hypothesis

Answer 25

accumulation of nonspecific bacteria tiggers the host inflammatory response which alters the local environment

Question 26

microbial homeostasis - host response hypothesis

Answer 26

although they cause inflammatory response leading to gingivitis, the pathogenic bacteria are not direct cause of destruction of tissues seen in periodontitis

Question 27

keystone pathogen - host response hypothesis

Answer 27

expands on other theory: that a specific bacterial species is key in creating the shift from symbiotic microbes to dysbiotic microbes in the biofilm community. In turn, the dysbiotic biofilm community triggers the uncontrolled host response that results in damage to the periodontal tissues

Question 28

A. actinomycetemcomitans (Aa)

Answer 28

Gram - Rod shaped Nonmotile Facultative (live in multiple environments) Late colonizer Mainly subgingival Found in periodontal disease

Question 29

S. Mitis

Answer 29

Gram positive Cocci shaped Non-motile Early colonizer Tooth associated plaque Facultative Found in both health and disease (but not associated with periodontitis)

Question 30

P. gingivalis

Answer 30

Includes vertical transmission Gram negative Obligate anaerobes (doesn’t like oxygen) Tissue associated plaque Considered keystone species (cause shift to disease via host immune response) It is Rods intermediate colonizers

Question 31

F. nucleatum

Answer 31

Gram negative Rod shaped bacterium Non-motile Intermediate colonizer Tissue associated plaque Facultative Found in periodontal disease Found in amniotic fluid

Question 32

T. forsythica

Answer 32

Gram negative Obligate anaerobes Rods Found in periodontal disease Non motile Member of the red complex Bridge between the early and late colonizing bacteria of dental plaque Tissue associated Late colonizer (likes to attach to p. Gingivalis esp)

Question 33

S. oralis

Answer 33

Gram positive Cocci Non-motile Early Colonizer Facultative Mostly associated with health tissue associated

Question 34

A. viscous

Answer 34

Gram positive Rods Facultative anaerobes Non-motile Early colonizer Tooth-associated plaque - health certain conditions dental plaque

Question 35

S. sanguis

Answer 35

Gram positive Cocci Motile Early colonizer Tooth associated plaque Facultative Can be found in both health and disease, but more abundant in health

Question 36

P. intermedia

Answer 36

Gram negative Rod shaped bacterium Non motile Intermediate colonizer Tooth associated plaque Obligate anaerobic Found in periodontal disease (aggressive necrotizing periodontitis

Question 37

C. gingivalis

Answer 37

Gram negative Bacilli Motile Tooth associated plaque Facultative Present in both health and periodontal disease; found in greater numbers in disease states

Question 38

aerobic, anaerobic, facultative anaerobic

Answer 38

aerobic - need O anaerobic - cant live with O Facultative - can exist with or without O

Question 39

Formation time lines:

Answer 39

minutes - free floating attach 2-4 hours - strongly attached micro colonies 6-12 hours - produce matrix 2-4 days - fully mature biofilm colonies recover from disruption

Question 40

Blocking-protective matrix

Answer 40

prevents large molecules and inflammatory cells from penetrating deeply into biofilm

Question 41

mutual protection

Answer 41

antibiotic resistant Bactria secrete protective enzymes to protect neighbouring bacteria

Question 42

5 stages of polymicrobial biofilm formation

Answer 42

1) initial attachment to pellicle 2) permanent attachment 3) maturation phase I 4) maturation phase II 5) dispersion

Question 43

Stage 1: Initial attachment

Answer 43

- Pellicle composed of glycoproteins and antibodies (always there) - Protects enamel from acid activity - Intermediate and late bacterial colonizers are unable to adhere to tooth until early colonizers do

Question 44

Stage 2: permanent attachment

Answer 44

- Microbes able to Withstand hydrodynamic forces attain permanent attachment - Produce substances to attract other microbes to the community

Question 45

Stage 3 - Maturation phase I: self-protective matrix formation

Answer 45

- Firmly attached bacteria surrounding protective secrete surrounding protective substance called extracellular protective matrix - Consists of proteins, glycolipids, bacterial DNA - Protects against host-generated immune defenses (chronic diseases is established)

Question 46

Step 4: Maturation II: mushroom-shaped microcolonies

Answer 46

- Microbes cluster together and form mushroom-shaped microcolonies that attach to the tooth by a narrow base - Grow at accelerated rate, thicker - Fluid channels penetrate the protective matrix - Communication (cell-to-cell) via chemical signals

Question 47

stage 5: Dispersion: escape form the matrix

Answer 47

Microbes disperse from the colony to spread and colonize other tooth surfaces

Question 48

Early colonizers

Answer 48

- Streptococcal species can attach to the tooth pellicle and to each other - Other early colonizers cannot attach to the pellicle but can congregate with the strep

Question 49

intermediate and late colonizers

Answer 49

- Must join in proper sequence - Periodontal pathogens are late colonizers of biofilm

Question 50

Biofilm components

Answer 50

- Mainly Microorganisms - Minor: carbohydrates, salivary components/proteins, desquamated cells, exudate, bacteria by-products (enzymes), inorganic products (Ca, Fl, K, etc)