SOS Flashcards
Majority of the microbes that cause oral disease are ___
bacteria and bacterial structure
inflammation of the gums is called
gingivitis
Oral microbiome is composed of __1.__, whereas mycobiome is composed of _2.___
- bacterium
2. fungi
T/F: bacteria have a true nucleus
False. Bacteria have a NUCLEOID (nuclear membrane absent). Also no membrane bound organelles
Bacterial cell multiplication occurs by ___ ___
bianry fission (dividing in two). 1—2—4—8—16—. Each daughter cell has the same DNA as parent cell
4 general composonents of bacterial structure
a. surface structures (ex flagella, fimbriae, pili, capsule/slime layer)
b. cell wall
c. cytoplasmic membrane
d. cytoplasm
What structure allows motility in bacteria?
flagella
flagella are composed of multiple subunits of the protein ____
flagellin
Function of fimbriae
- fimbriae are shorter and straighter than flagella
- found all over bacterial cell
- aid in BACTERIAL ATTACHMENT to surfaces or to other bacteria
what surface structure serve to promote gene transfer between bacteria and attachment?
pili
Which is more numerous in bacteria? Pili or fimbrae?
Pili < fimbrae
a slime layer is (more/less) diffuse than a capsule
more
Capsule / slime-layer serve to promote:
a) adhesion to tissue surfaces
b) evasion of phagocytosis by immune cells
c) provides resistance to environmental stress (eg. drying)
d) acts as disguise from an immune response
e) supply of emergency food resevoir
Which strain of bacteria was isolated from an adult patient with periodontitis?
P. gingivalis
Which strain of bacteria was isolated form a patient with cystic fibrosis?
P. aeruginosa
What acids present in the cell wall of the mycolata taxon and what effect does this have?
Mycolic acids. These prevent gram staining
roughly 50% of periodontitis patients harbour ____
methanogens
The amount of methanogens increases with increasing ____ ___
pocket depth
Methanogen abundance is positively correclated with ____ ____ (an obligatiev anaerobe)
prevotella intermedia
Peptidoglycan function
- mech protection
- activates alternative complement pathways (induces inflammation via C3a and C5a)
- Gram + cells are more resistant to detergents and complement
What is found on the outer membrane of Gram -ve bacteria?
Lipopolysaccharides. Used as an ADHESIVE. Highly toxic to animals
Lipopolysaccharides consist of:
- lipid A region (toxic)
- R polysaccharide core region
- carbohydrate chains (O region, antigenic)
Lypopolysaccharide activates…
alternative complement pathway (LPS induces inflammation)
Lipopolysaccharides act as barriers to what?
large and hydrophobic molecules.
Lysosomes and antimicrobials
Purified LPS causes
fever, intravasculat coagulation, hypotension, shock and may even cause death
Lipid A is highly conserved among gram ____ bacteria
negative
in the cell wall
What does lipid A do
-induces monocytes and macrophages to release proinflammatory mediators (eg. cytokines, which are molecules that help the cell move)
-Activated coagulation cascade
LIPID A IS A POTENT STIMULATOR OF THE IMMUNE RESPONSE
Which acids are present in gram +ve cell walls?
teichoic acids.
- strong neg charge
- strong antigens
- used as an adhesin
- not present in most gram -ve bacteria
T/F: cytoplasmic membrane is a phospholipid bilayer in gram -ve and +ve bacteria
true
Functions of the cytoplasmic membrane:
- selective barrier
- transport in and out of cell
- secretion
- NRG generation (ATP synthesis)
gene transfer in bacteria
- conjugation
- transduction
- transformation
- transposition
What causes antibiotic resistance?
“jumping genes.” One gene integrates into another, causing destruction of the sequence in the other gene (transposition)
based on type of action, antibiotics are either __ or __-
bacteriostatic or bactiocidal
antibiotic synergism
when 2 bactericidal antibiotics are given together and exert a greater effect than when given seperately
antibiotic antagonism
when a bacteriostatic and a bactericidal antibiotic are given together and their effectiveness is reduced
penicillin is only effective against gram ___ bacteria
positive
Common cellular target of antibiotics
- cell wall (eg. penicillin)
- cell membrane
- nucleic acids
- protein synthesis
- antimetabolites (enzymes)
Which taste receptors are activated by multiple antibiotics?
chemosensory BITTER taste receptors (T2Rs)
From where should sample be taken when examining ECC (early childhood caries?
from plaque bacteria, since this is different from bacteria in the buccal cavity and spit
plaque bacteria associated with caries
- streptococcus mutans (+) = cocci
- streptococcus sanguis (+) = cocci
- actinomyces spp (+) = branching rods
- lactobacillus (+) = rods
Angular chailitis
- often confused with cold sores
- caused by staphylococcus aureus
The oral micloflora are mostly __1.__, but changes in physiological conditions results in some of the oral microflora turning into 2.____ ____
- commensals
2. opportunistic pathogens
Major oral habitats
- buccal mucosa (inside the cheek)
- dorsum of tongue (highest concentration)
- tooth surfaces
- cervicular epithelium
Physiological roles of gingival epithelium
- protects against invasion by periodontal pathogen
- barrier
