Microbiology 1010 – Lecture Notes
15.12 Filamentous Actinobacteria: Streptomyces
Genus of filamentous Gram positives
Form branching hyphae and mycelia
Hyphae produce reproductive spores for dispersal –
conidia o Not endospores
The capacity to branch (form structures similar to fungi)
Spores are not the same as endospore structures.
Found inside what was once the filamentous structure.
15.12 Filamentous Actinobacteria: Streptomyces (Continued…)
Most are obligate aerobes
Live in well aerated soils
Give soil its earthy smell - geosmins
Also produce substances that kill or inhibit the growth of other microbes - antibiotics
Produces streptomycin, a broad spectrum protein synthesis inhibitor active against
Gram negative bacteria.
They have to live within soils that are well aerated (a lot of oxygen concentration)
Microbial antagonism – destroys all it’s competitors around them so he can have the nutrients. We
take the soil and abstract the substance and use it as an antibiotic
Streptomycin = targets 70s ribosomes
101 Microbiology 1010 – Lecture Notes
Large, heterogeneous phylum of Gram negative bacteria o
Aerobes and anaerobes
o Few unifying characteristics
Example: Bacteroides thetaiotaomicron
Numerically dominant microbe in the human large intestine
Produces enzymes to degrade polysaccharides, greatly increasing the variety of plant
polymers that can be digested in the human gut.
Gram neg. by definition.
Contains puss, dead immune cells – abscess
102 Microbiology 1010 – Lecture Notes
Gram negative cell wall type, but
Obligate intracellular parasites
Unique life-cycle with two types of
Small dense cell, resists
Allows infection of new
Larger vegetative cells
Multiply inside an
But, are not infective
Example: Chlamydia trachomatis
Trachoma (infection of the eye)
Causes scarring and blindness.
Doesn't have ability to accumulate there, it will still luck in your tissues.
Elementary = Able to continue with normal actives and it also allows for the infection of the new
host. More equipped to get into a living cell.
Interferes with normal physiology of the eye.
Babies get given this eye drops once they are born (causes blindness)
No peptidoglycan so not classified as gram positive