genus streptomyces Flashcards
what phylum do streptomyces belong to
actinobacteria
members of phylum actinobacteria are gram __
positive
what is the largest genus belonging to phylum actinobacteria
streptomyces
which location are streptomyces mostly found
the soil
___ ___ trophs belong to genus streptomyces
chemoorganotrophs
what are chemoorganotrophs
they use organic compounds for electron and energy sources
are streptomyces aerobic or anaerobic
aerobic
what pH range do streptomyces like? what is the term for this
neutrophiles: pH 6.5-8
what temperature do streptomyces like? what is the term for this
mesophiles: 10-37C
T or F: streptomyces are motile
false; they’re non-motile
T or F: streptomyces are filamentous
true
what are 2 types of hyphae that streptomyces produce
vegetative and aerial
what do aerial hyphae produce
exospores
T or F: endospores and exospores are the same
FALSE: they’re not the same
are endospores used for reproduction?
no
are exospores used for reproduction
yes
describe the life cycle of streptomyces
vegetative hyphae grow into the soil looking for nutrients. When nutrients become limiting, they produce aerial hyphae. Aerial hyphae cannibalize the vegetative hyphae as a source of nutrients. The hyphae start to curl and produce exospores, the spore is released, the cycle continues
T or F: on plates, streptomyces produce no pigment
false; they can produce lots of different pigments, some of which may be diffusable
T or F: most streptomyces are non pathogenic
true
how many different species does genus streptomyces contain
844
in the soil, streptomyces make up between __-__% of the culturable micribial population
1-20%
T or F: streptomyces are more drought resistant than other bacteria
true
describe the role that streptomyces play in the soil ecosystem (2)
they degrade organic material and produce lots of different exoenzymes that can degrade a variety of minerals
list some material that streptomyces can degrade (4)
keratin, lignin, chitin, starch
describe the benefit of using starch casein agar in the lab
starch: not a lot of bacteria can use it as a carbon source. Streptomyces can degrade starch into smaller pieces
casein: used instead of peptones. It’s large and can’t cross the PM. streptomyces produce casein-digesting proteases
define secondary metabolite
metabolite that’s produced but not essential for the survival of the bacterium
what is geosmin
a secondary metabolite that gives dirt it’s smell after it rains
list some secondary metabolites that streptomyces may produce
anti-fungals, anti-virals, anti-parasitics, anti-cancer agents, antibacterials
when in the streptomyces life cycle are antibiotics produced
during the switch from vegetative to aerial hyphae (when the bacterium becomes stressed due to low nutrients)
list 4 different classes of antibiotics that streptomyces produce
tetracycline, chloramphenicol, novobiocin, vancomycin
what does tetracycline do
inhibits protein synthesis by binding to the small ribosomal subunit
what does chloramphenicol do
inhibits protein synthesis by binding to the large ribosomal subunit
what does novobiocin do
inhibits DNA synthesis
what does vancomycin do
inhibits cell wall formation
what are immunity genes
genes that antibiotic-producing streptomyces have that allows them to resist the action of the antibiotics that they produce
T or F: streptomyces have been found to be resistant to multiple antibiotics, not only the ones that they produce
true
how can streptomyces be resistant to multiple antibiotics, not only the ones that they produce
via HGT
streptomyces genomes may be more than __ (include units)
10 Mb (megabases)
describe the chromosome shape/number in streptomyces
single linear chromosome
describe the GC content of streptomyces
high GC content: 67-78%
list some ways in which we can awaken silent gene clusters
- co culture with other streptomyces sp.
- co-culture with other bacteria
- stress the bacteria in the lab with unfavourable conditions
- incorporate materials from their native environment
- culture with rare earth elements
