microbiology Flashcards
plaque biofilm
organized cooperating community of organisms with specific inter-bacterial and host-bacterial interaction s
biofilm attachment begins when ______________ adhere to acquired pellicle.
planktonic bacteria
salivary pellicle consists of ____________ and ___________.
salivary glycoproteins, antibodies
during the attachment phase of biofilm formation, _________ and __________ change within the pellicle.
surface charge and free energy
________ attachers have specific attachment structures like fimbriae, extracellular polymenrs and glycocalyx.
rapid
following attachment bacteria begin to _____________ and cellular growth becomes active.
synthesize new outer membrane proteins
what is co-aggregation during biofilm growth phase?
cell-to-cell recognition of genetically distinct cell types; 2 distinct species are needed to interact, cells are suspended then form clumps which attach to pellicle
what is co-adhesion during biofilm formation?
interactions between suspended and already adhering micro-organisms.
what influences co-adhesion and what can modify it?
influenced by temperature (no co-adhesion at temps greater than 37degC) and lactose (increase lactose, decrease co-adhesion); modified by mouthwash, fluoride toothpaste, etc.
during biofilm maturation, increase __________, _____ and _________.
replication and matrix formation, diversity and ecological succession
primary colonizers bind to the ______________.
salivary pellicle
T/F: primary colonizers can be both gr+ and gr-
True
T/F: in general, no-mutan streptococci are associated with disease
False: ass with health
example of secondary colonizer (bridge species).
fusobacterium nucleatum- prolific cooagregator
T/F: pathogenic species are gr+ secondary colonizers
False, gr- tertiary colonziers
when a biofilm increases in thickness, a _______ gradient develops, with completely anaerobic conditions in the deeper layers; while a ________ gradient develops as a result of bacterial metabolism
oxygen, reverse fermentation product
What nourishes the supragingival plaque?
dietary products dissolved in the plaque
What nourishes subgingival plaque?
periodontal tissues and blood (indirectly affected by diet)
How does subgingival plaque get nutrients from tissues and blood?
bacterial hydrolytic enzymes breakdown host macro-molecules into peptides and amino acids
what are 3 sources of baterial matrix?
dead bacterial cells, saliva, gingival exudate (JE fluid)
what forms the backbone of biofilm?
exopolysaccharides
the ______ layer of the biofilm contains a dense layer of microbes, polysaccharide matrix and steep diffusion gradients.
lower
Why is mechanical therapy followed by antibiotics the best way to remove a biofilm-induced infection?
due to steep diffusion gradients of lower layer
the _________ layer of biofilm is irregular in appearance and extends into surrounding medium
loose
