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Microbial Structure: Appendages (Flagella (Spirochetal (inside of outer…
Microbial Structure: Appendages
Flagella
Structure
gram pos: 2 protein rings and a rod to anchor into cell wall, hook component that attaches filament to rod
gram neg: same as gram pos with more rings
Movement: fin or propeller
motility test used to determine if organism is mobile; bacteria will only go where the medium was stabbed if no flagella
overall net movement toward stimuli
Spirochetal
inside of outer membrane
bacteria moves like a cork screw
Treponema pallidum, Borellia burgdorferi
Type III Secretion
needle punches into host cell secrete virulence factors that allow it to be pathogenic
Shigella spp, Salmonella spp, E. coli, Vibirio spp, Yersinia pestis, Clamydia trachomatis, Pseudomonas spp
more rigid than regular flagella
Primary role is movement; can be a sensory organelle; secretes molecules
monotrichous: one on one side; amphitrichous: off of both poles; lophotrichous: a lot on one end; peritrichous: all over
Pili
Type IV secretion
similar to type III, specialized pilus vs specialized flagella
secrete (or take up) molecules and virulence factors
Neisseria meningitidis, Helicobacter pylori, Bordetella pertussis, Legionella pneumophila
base anchors into cell envelope; needle assembles when it sensed a host cell
Conjugation Pilus (Sex Pilus)
transfer genetic material from donor to recipient
no new organism made
recipient becomes a donor
information can be sent quickly through the population
Hfr: F factor enters chromosome; more permanent bc it is hard to lose a chromosome
harder than flagella, bristle like
Fimbriae
fimbrial adhesion
Neisseria gonorrhoeae, Klebsiella pneumonia
specialized attachment or adherence pili; most important part of pathogenicity; often called CFA (colonization factor antigens)
fimbriae are usually the first thing to attach to host cell; allows other proteins to attach; once a layer has attached its fimbriae can interact w/ fimbriae from other bacterial cells (colonization)
bacteria in urinary tract and intestines have to use fimbrial adhesion bc they move too fast to get close enough for afimbrial adhesion
afimbrial adhesion
attachment without fimbriae; adhesins found on cell wall;
glycocalyx attachment
Types of E. coli (all use fimbrial adhesion)
Intesinal
Enteropathogenic (EPEC); moderately invasive, no toxins, diarrhea
Enterotoxigenic (ETEC): noninvasive, produces toxins, diarrhea
Enteroinvasive (EIEC): highly invasive, produces toxins, dysentery
Enterohemorrhagic (EHEC): moderately invasive, produces toxins, hemorragic, hemolytic, lyses red blood cells, kidney failure (E. coli O157:H7)
Enteroaggregative (EAEC): noninvasive, forms aggregates (clumps), produce toxins, diarrhea
Uropathogenic (UPEC): 905 of UTI's