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Flashcards in Biology of Infectious Agents Deck (31):
1

muticellular community of bacteria attached to a surface, surrounded by a self-produced extracellular polymer matrix

biofilm

2

what percentage of microbial infections are caused by biofilm

60-80%

3

there are how many different species of oral biofilm (plaque)

>600

4

what are free swimming bacteria called

planktonic

5

what is the definition when bacteria are irreversibly attacehed

sessile

6

what is surface conditioning

absorbtion of organic molecules onto a clean surface forming a conditioning film easy for bacteria to adhere/attach to

7

what is the name given to the 1st bacteria to attach to a conditioned surface

pioneer bacteria or primary colonizers

8

what bonds bacteria in reversible adhesion

van der waals forces

9

what bonds bacteria in irreversible adhesion

adhesion molecules (proteins)

10

secondary colonizers bind to ?

primary colonizers

11

fusobacterium nucleatum (F. nucleatum) has what purpose in biofilm formation

bridge species, meaning it bridges gap b/w early and late colonizers

12

what does cooperative consortia mean with regards to formation of biofilm

specific species of biofilm group together based upon their most important needs (ex. anearobic vs aerobic)

13

what volume percentage does the extracellular polymer make up vs. the actual bacteria in biofilm ?

polymer 75-95 %
bacteria 5-25 %

14

what are the 3 types of biofilm dispersal

active - enzyme degradation of extracellular polymer
passive - fluid flow causing movement, human intervention
new pioneer cells

15

what are the stages of the biofilm cycle

attachment, coloniization, growth, maturation, dispersal
REPEAT

16

What are 4 advantages of biofilm to microbes

-resistant to antimicrobials
-resistant to host defenses (WBC, phagocytes)
-resistant to mechanical removal
-use eachothers waste/resources for energy

17

what are the advantages of biofilm to the host

presence of good species of biofilm can prevent colonization of harmful species by
- occupying space
-producing defense molecules killing other species

18

adhesion molecules would be considered primary or secondary colonizers ?

primary colonizers

19

what is quorum sensing

process of cell-cell communication of bacteria measuring density of species w/in an environment

20

what is the purpose of quorum sensing

to synchronize behaviors that individual bacteria can't perform alone

21

what stimulates light production by enzyme luciferase

when a threshold concentration of an inducer is reached

22

what is the signal molecule in gram negative bacteria

Acyl homoserine lactone (AHL)

23

what type of quorum sensing uses the same molecule for both a receeptor and regulater

Gram negative bacteria

24

T/F all quorum sensing is species specific

F

25

what is the signal molecule in gram positive quorum sensing

oligopeptide

26

what type of quorum sensing involves peptides leaving the cell then binding to a receptor and activating a downstream repsonse/regulatory gene

gram positive bacteria

27

what is the signal molecule used in quorum sensing of multiple species (non-species specific)

auto-inducer 2 (AI-2)

28

T/f Quorum sensing triggers 1 specific process for all bacteria

F, triggers many different responses

29

T/F Quorum sensing can trigger virulent genes liek toxins, proteases, and lysins

T

30

How could you inhibit biofilm formation

Block quorum sensing, cuz quorum sensing triggers biofilm formation

31

If you were to inhibit biofilm formation by inhibiting quorum sensing what would you attack ?

-signalling molecules
-receptors