What would happen if mycoplasma lost it's P1 Adhesin?
loss of virulence.
bacilli - coccoidal (pleomorphic) closely related to gram -ve (do not stain well)
Unique feature of Rickettsiae
Obligate intracellular unable to prod. sufficient energy to replicate CANNOT be cultured on AGAR This is because it does not possess Coenzyme A, NAD or ATP - all obtained from host.
Is Rickettsiae Zoonotic?
yes, spread via arthropod vectors (ticks, lice, fleas, mites)
Anaplasmataceae & Coxiella
Obligate intracellular pathogens
2 groups: 1) human infections only 2) Zoonotic infections (birds -- > man) (weird)
Unique feature of Chlamydia
Obligate intracellular pathogens Grow in cytoplasmic vacuoles in limited host cell types Depend upon host for ATP & NAD Cannot synthesize ATP or reoxidize NADP No detectible flavoproteins or cytochromes NO peptidoglycan detected in 1 stage of life cycle
Developmental cycle of Chlamydia
1) EB (elementary body= non-replicating;infections; adapted for extracellular survival) taken into host cell by phagocytosis 2) Next 8 hrs EB reorganizes --> RB (reticulate body (non-infectious; replicating) 3) RB grows & divides by binary fission 4) 24-48 hr RB reorganizes -> EB 5) Completed: host cell liberates EB (EB taken in--> (EB->RB) --> (RB binary fission)--> EB)
Are fungi eukaryotic? (ie have nucleus/nuclear membranes?)
Fungi are saprobes. What's a saprobe?
lives on dead or decaying organic matter
Yeast vs Molds
Yeast = unicellular; reproduce asexually via budding. form pseudohyphae
Molds: Multicellular (long filamentous HYPHAE, which intertwine to form MYCELIUM); Sexual or Asexual
Hyphae can be septate or aseptate. What's the difference?
an intertwined mat of hyphae 2 portions: 1) Vegetative: attached to substrate/penetrates to obtain substrate 2) Reproductive - Aerial structures; Asexual reproduction propagules (conidia)
What is meant by Dimorphic Fungi?
exhibit 2 different forms (depending on Chemical & physical Factors) 1) Free-living State - Mycelial or Hyphal forms 2) Parasitic state: Yeast
How is Aspergillus an exception to Fungal Dimorphism?
ALWAYS in mycelial phase (ie free-living state, even when in deep tissue)