Download Actinomycetes and Streptomycetes

Actinomycetes and
Streptomycetes
By Ashley Dvorak
and Aly Johnston
Actinomycetes
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High G+C Gram-positive bacteria
Most bacteria found in Phylum Actinobacteria
are often just called ‘Actinomycetes’
Phylum Actinobacteria, Subclass
Actinobacteridae, Order Actinomycetales
rRNA Classification
Phylogenic Relationships
Structure/Characteristics
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Mostly aerobic, some anaerobic
Grow on agar above the surface and below the
surface
Often form mycelium (massive branching
hyphae) with conidia (or conidiospores –
asexual, thin-walled spores)
Not heat-resistant, but adaptive. Not motile.
Agar Growth
Spores
Cell Walls
Location/Function
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Located primarily in soil or aquatic
environments; widely distributed
Can degrade numerous organic compounds or
mineralize organic materials, produce most of
the medically useful antibiotics, and some exist
as pathogens
Suborder Actinomycineae
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Straight or slightly curved rods, are facultative or
strict anaerobes, found in mucosal surfaces
(nose or oral cavity)
A. israelii, A. bovis (Acinomycosis caused by
infection, trauma or surgery of the face, teeth,
throat, and sometimes the heart or abdomen)
Actinomyces
Suborder Corynebacterineae
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Corynebacterium
Mycobacterium
Nocardia / Rhodococcus
Corynebacterium
Mycobacterium
Nocardia
Suborder Streptomycineae
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One Family : Streptomycetaceae
Three Genera, most important Streptomyces
Aerial hyphae divide in a single plane to form
chains of non-motile conidiospores
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Smooth, spiny, warty
Streptomyces Spores
Streptomyces
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All strict aerobes
Cell wall type I
0.5-1.0 µm in diameter, varying lengths
Predominantly found in soil
Has many morphological and physiological
characteristics
Conidia
Streptomycetes
Ecological and Medical Importance
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Mineralization
Aerobically degrades multiple resistant
substances
Synthesis of antibiotics
mainly non-pathogenic
S. griseus
S. scabies