microbes lecture 4- global impacts of microbes

Question 1

what does the word photoroph mean?

Answer 1

light energy

Question 2

what does chemotroph mean?

Answer 2

chemical oxidation energy

Question 3

what is an autograph?

Answer 3

carbon dioxide

Question 4

what is a heterotroph?

Answer 4

organic compounds

Question 5

what is a psychrophile?

Answer 5

Optimum growth <15ºC
90% ocean is <5ºC
Chlamydomonas nivalis, Listeria monocytogenes

Low temperature, membrane is too solid
Keep interactive and fluid
Increase unsaturated fats
Good fat = liquid

Question 6

what is a thermophile?

Answer 6

Spores used as a biological indicator, measuring sterilisation

Question 7

what is a hyperthermophile?

Answer 7

Survival at >70ºC
Not only tolerate, but require for survival
Thermus aquaticus

High temperature, membrane becoming too liquid
To maintain integrity, solidify fats
Increase saturated fat content
Bad fat = solid

Question 8

what is a mesophile?

Answer 8

Optimum growth at body temperature
Human pathogens

Question 9

what are cryoprotectants?

Answer 9

COLD/HEAT SHOCK PROTEINS
- prevent proteins unfolding/denaturing
- maintain correct structure and activity

Question 10

how do organisms survive extreme temperatures?

Answer 10

the cell membrane

Question 11

what is the neritic zone?

Answer 11

Mild temp, low pressure, nutrient-rich
Diverse marine life
Photosynthetic organisms

Question 12

what is the oceanic zone?

Answer 12

Pressure increases with depth
Chemotrophs
Not as unstable as once thought

Question 13

what is oceanic plankton?

Answer 13

Oceanic planktons are responsible for the production of an estimated 50-80% of the oxygen on Earth.
One specific bacterial species, known as Prochlorococcus, is responsible for producing one-fifth (20%) of the oxygen on our planet.
Along withSynechococcus(another genus of cyanobacteria that co-occurs withProchlorococcus) these cyanobacteria are responsible for approximately 50% of marine carbon fixation
Prochlorococcus multiplies in a day
Adapts to changing environment

Question 14

what does plastic do in the environment

Answer 14

Toxic effects
Platforms for colonisation
Provide carbon source

Question 15

what is biodegredation?

Answer 15

the physical or chemical change of a material by microorganisms

aerobic happens with oxygen to produce co2 h2o and residual carbon and anaerobic happens without oxygen making methane also

Question 16

what are different microbes used for?

Answer 16

-Application of DNA polymerase I fromThermus aquaticus(Taq polymerase) transformed the field of molecular biology
-Restriction enzyme or restriction endonuclease
–>Proteins produced by bacteria that can cleave DNA at specific sites
Bacteria uses restriction enzyme to defend from viral (bacteriophage) infection

Question 17

what have restriction enzymes made possible?

Answer 17

the foundation for recombinant technology

Question 18

what is a recombinant vaccine?

Answer 18

-Hepatitis B virus (HBV) infection causes chronic liver disease.
-The current vaccines are produced by expressing the hepatitis B surface antigen (HBsAg) in yeast cells.
-Recently, the recombinant vaccine for human papillomaviruses (HPVs) and SARS-Cov2 has also been produced

eg in ChAdOx1 nCoV-19 vaccine (AZD1222)- used a replication-deficient chimpanzee adenoviral vector ChAdOx1 and introduced SARS-CoV-2 structural surface glycoprotein antigen (spike protein) gene

Question 19

microbes in medicine (cancer)

Answer 19

Often associate microbes with disease, including their role in cancer..
-Cervical (and other) cancer – Human papillomavirus (HPV)
-Gastric cancer – Helicobacter pylori
-Bladder cancer – Schistosoma haematobium

Question 20

microbes in medicine (antibiotics)

Answer 20

Florey and chain rediscovered flemings work and were able to show..
-Efficacy in humans
-Construction of industrial scale equipment
-isolate productive penicillin-secreting fungi

Question 21

what about penicillin?

Answer 21

After penicillin was discovered, the race was on to identify other organisms that produce antibiotics - Actinomycetes

-Filamentous Gram +ve bacteria
-Isolated from soil, marine water, insects, sand
-Discovered by Selman Waksman and isolated -streptomycin in 1943
-Streptomyces griseus
-First curative agent of tuberculosis

Question 22

what is crispr?

Answer 22

Cas9 protein- Nuclease
Pre-CRISPR RNA (pre-crRNA)- needs to be converted to crRNA
Trans encoded small RNA (tracrRNA)- coverts pre-crRNA to crRNA
Guide RNA (gRNA)- chimera of crRNA and tracrRNA

Feature of bacteria and archaea for acquired immunity
The first CRISPR sequence was discovered in E. coli K12 over 30 years ago
~36% of bacteria and ~75% of archaea are known to contain the CRISPR-Cas system
Prokaryotes containing CRISPRs are resistant to viruses or plasmids containing sequences matching the spacers
CRISPR-Cas9 can target any DNA sequence and generate cleavage
Emmanuelle Charpentier and Jennifer A. Doudna received the Nobel Prize in Chemistry 2020 for the discovery of the CRISPR-Cas9 system