The Keystone Pathogen Hypothesis- Exam III

Question 1

states that certain low-abundance microbial pathogens can orchestrate inflammatory disease by remodeling a normally benign microbiota into a dysbiotic one.

Answer 1

Keystone pathogen hypothesis

Question 2

The quest to identify specific periodontal pathogens has led to significant progress, including the identification of a number of candidates, mostly ___ the colonize ___.

Answer 2

gram-negative anaerobic bacteria; sub gingival tooth sites

Question 3

In the quest to identify specific periodontal pathogens, three species have been identified which comprise the so-called _____, and are frequently isolated together and are strongly associated with ___.

Answer 3

red complex; diseases sites in mouth

Question 4

What category of bacteria make up the “red complex”

Answer 4

gram-negative anaerobic bacteria

Question 5

What is the red complex associated with?

Answer 5

disease sites in the mouth

Question 6

The bacteria comprising the red complex are frequently:

Answer 6

isolated together

Question 7

List the species of bacteria comprising the red complex:

Answer 7

1. porphyromonas gingivalis
2. treponema denticola
3. tannerella forsythia

Question 8

The Arg-specific cysteine proteinases (gingipains) of P. gingivalis exhibit:

Answer 8

complement C5 convertase-like activity

Question 9

The complement C5 convertase-like activity of the Arg-specific cysteine proteinases (gingipains) generates high levels of ___ locally, to activate the:

Answer 9

C5a; C5a receptor on leukocytes

Question 10

C5aR signaling is involved in crosswalks with:

Answer 10

TLR2

Question 11

C5aR signaling is involved in crosswalks with TLR2 which is activated parallel by:

Answer 11

P. gingivalis surface ligands

Question 12

C5aR signaling is involved in crosswalks with TLR2 which is activated parallel by P. gingivalis surface ligands and this crosstalk leads to:

Answer 12

enhanced inflammation but impaired leukocyte killing activity

Question 13

P. gingivalis can also inhibit the synthesis of ___ by epithelial cells to delay the recruitment of neutrophils and facilitate its initial colonization of the periodontium.

Answer 13

IL-8

Question 14

_____ can also inhibit the synthesis of IL8 by epithelial cells to delay the recruitment of neutrophils and facilitate its initial colonization of the periodontium.

Answer 14

P. gingival

Question 15

P. gingivalis can also inhibit the synthesis of IL8 by epithelial cells to ______ and facilitate its initial colonization of the periodontium.

Answer 15

delay the recruitment of neutrophils

Question 16

P. gingivalis can also inhibit the synthesis of IL8 by epithelial cells to delay the recruitment of neutrophils and facilitate its initial

Answer 16

colonization of the periodontium

Question 17

The synthesis of ___ by the junctional gingival epithelium, adjacent to the tooth surface is thought to be an important feature of healthy periodontium

Answer 17

IL8

Question 18

The synthesis of IL8 by the _____, adjacent to the tooth surface is thought to be an important feature of healthy periodontium

Answer 18

junctional gingival epithelium

Question 19

The synthesis of IL8 by the junctional gingival epithelium, adjacent to the tooth surface is thought to be an important feature:

Answer 19

healthy periodontium

Question 20

Why is the synthesis of IL8 by the junctional gingival epithelium, thought to be an important feature of healthy periodontium?

Answer 20

because it generates a gradient for recruitment of neutrophils into the gingival crevice

Question 21

The subversion of leukocytes by _____ may allow uncontrolled growth of other species in the same biofilm

Answer 21

wild-type P. gingivalis

Question 22

The subversion of leukocytes by P. gingivalis may allow uncontrolled growth of other species in the same biofilm.

This is consistent with the observed elevation of _____ following P. gingivalis colonization of the murine periodontium

Answer 22

total microbiota

Question 23

Uncontrolled bacterial growth lead to:

Answer 23

enhanced complement-dependent destructive inflammation

Question 24

Uncontrolled bacterial growth lead to enhanced complement-dependent destructive inflammation, which generates:

Answer 24

abundant tissue breakdown products

Question 25

Uncontrolled bacterial growth lead to enhanced complement-dependent destructive inflammation, which generates abundant tissue breakdown products that serve the:

Answer 25

nutritional needs of bacteria

Question 26

The inflammatory environmental changes can be better exploited by:

Answer 26

proteolytic and asacharolytic bacteria

Question 27

Proteolytic and asacharolytic bacteria are associated with ____ rather than ____

Answer 27

periodontal disease; health

Question 28

Specific removal of ____ from the periodontal biofilm (by means of a C5aR antagonist) reverse the dysbiotic changes , suggesting that dysbiotic diseases could be treated by specific targeting of keystone pathogens

Answer 28

P. Gingivalis

Question 29

Specific removal of P. Gingivalis from the periodontal biofilm (by means of ______) reverse the dysbiotic changes , suggesting that dysbiotic diseases could be treated by specific targeting of keystone pathogens

Answer 29

C5aR antagonist

Question 30

What results with specific removal of P.Gingivalis from the periodontal biofilm (by means of a C5aR antagonist) ?

Answer 30

reversal of dysbiotic changes

Question 31

Specific removal of P. Gingivalis from the periodontal biofilm (by means of C5aR) reverse the dysbiotic changes: What does this suggest?

Answer 31

that dysbiotic diseases could be treated by specific targeting of keystone pathogens

Question 32

Despite its low-level colonization of the periodontium, P. gingivalis causes ____ through ___

Answer 32

inflammatory periodontitis through dysbiosis