genus streptomyces

Question 1

what phylum do streptomyces belong to

Answer 1

actinobacteria

Question 2

members of phylum actinobacteria are gram __

Answer 2

positive

Question 3

what is the largest genus belonging to phylum actinobacteria

Answer 3

streptomyces

Question 4

which location are streptomyces mostly found

Answer 4

the soil

Question 5

___ ___ trophs belong to genus streptomyces

Answer 5

chemoorganotrophs

Question 6

what are chemoorganotrophs

Answer 6

they use organic compounds for electron and energy sources

Question 7

are streptomyces aerobic or anaerobic

Answer 7

aerobic

Question 8

what pH range do streptomyces like? what is the term for this

Answer 8

neutrophiles: pH 6.5-8

Question 9

what temperature do streptomyces like? what is the term for this

Answer 9

mesophiles: 10-37C

Question 10

T or F: streptomyces are motile

Answer 10

false; they’re non-motile

Question 11

T or F: streptomyces are filamentous

Answer 11

true

Question 12

what are 2 types of hyphae that streptomyces produce

Answer 12

vegetative and aerial

Question 13

what do aerial hyphae produce

Answer 13

exospores

Question 14

T or F: endospores and exospores are the same

Answer 14

FALSE: they’re not the same

Question 15

are endospores used for reproduction?

Answer 15

no

Question 16

are exospores used for reproduction

Answer 16

yes

Question 17

describe the life cycle of streptomyces

Answer 17

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

Question 18

T or F: on plates, streptomyces produce no pigment

Answer 18

false; they can produce lots of different pigments, some of which may be diffusable

Question 19

T or F: most streptomyces are non pathogenic

Answer 19

true

Question 20

how many different species does genus streptomyces contain

Answer 20

844

Question 21

in the soil, streptomyces make up between __-__% of the culturable micribial population

Answer 21

1-20%

Question 22

T or F: streptomyces are more drought resistant than other bacteria

Answer 22

true

Question 23

describe the role that streptomyces play in the soil ecosystem (2)

Answer 23

they degrade organic material and produce lots of different exoenzymes that can degrade a variety of minerals

Question 24

list some material that streptomyces can degrade (4)

Answer 24

keratin, lignin, chitin, starch

Question 25

describe the benefit of using starch casein agar in the lab

Answer 25

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

Question 26

define secondary metabolite

Answer 26

metabolite that’s produced but not essential for the survival of the bacterium

Question 27

what is geosmin

Answer 27

a secondary metabolite that gives dirt it’s smell after it rains

Question 28

list some secondary metabolites that streptomyces may produce

Answer 28

anti-fungals, anti-virals, anti-parasitics, anti-cancer agents, antibacterials

Question 29

when in the streptomyces life cycle are antibiotics produced

Answer 29

during the switch from vegetative to aerial hyphae (when the bacterium becomes stressed due to low nutrients)

Question 30

list 4 different classes of antibiotics that streptomyces produce

Answer 30

tetracycline, chloramphenicol, novobiocin, vancomycin

Question 31

what does tetracycline do

Answer 31

inhibits protein synthesis by binding to the small ribosomal subunit

Question 32

what does chloramphenicol do

Answer 32

inhibits protein synthesis by binding to the large ribosomal subunit

Question 33

what does novobiocin do

Answer 33

inhibits DNA synthesis

Question 34

what does vancomycin do

Answer 34

inhibits cell wall formation

Question 35

what are immunity genes

Answer 35

genes that antibiotic-producing streptomyces have that allows them to resist the action of the antibiotics that they produce

Question 36

T or F: streptomyces have been found to be resistant to multiple antibiotics, not only the ones that they produce

Answer 36

true

Question 37

how can streptomyces be resistant to multiple antibiotics, not only the ones that they produce

Answer 37

via HGT

Question 38

streptomyces genomes may be more than __ (include units)

Answer 38

10 Mb (megabases)

Question 39

describe the chromosome shape/number in streptomyces

Answer 39

single linear chromosome

Question 40

describe the GC content of streptomyces

Answer 40

high GC content: 67-78%

Question 41

list some ways in which we can awaken silent gene clusters

Answer 41

• 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