Positive uses of infectious pathogens Flashcards
get good
How is beer made?
Yeast ferments sugars in barley, then removed and pasteurised
How is cheese made?
By addition of rennet
mainly chymosin = aspartic acid protease
originally from inner mucosa of 4th stomach of calf
now made by microbes
e.g. Rhizopus chinensis (bread mold)
How is vinegar made?
HISTORICALLY: Produced when wine exposed to air
Contaminated with Acetobacter:
oxidised alcohol to acetic acid
PRESENT: Ethanol produced by yeast.
Converted to acetic acid by addition of Acetobacter
How is pruteen made?
Pruteen was 1st single-cell protein animal feed
Made from methylophilus methlyotrophus bacteria + methanol
Now used in Quorn
Microbes in sewage systems
Large cities produce > 1000 tonnes solid waste/day
Autotrophs (use inorganic compounds) and heterotrophs (use organic compounds) are used to breakdown (activated sludge process, a multi-chamber reactor unit that uses highly concentrated microorganisms) organic material
-Also, fungi, rotifers and protozoa are present
How are microbes used in bioremediation?
Use of microbes to break down dangerous
chemicals
e.g. Alcanivorax borkumensis
Gram negative marine gamma
proteobacterium
Uses oil as energy source
Converts it to less harmful form
Which bacteria can make plastic and how is it used?
polyhydroxybutyrate (PHB) is produced by Alcaligenes eutrophus, Bacillus megaterium. It is a biodegradable plastic and is biocompatible, can be used medically
How can bacteria be used to produce exogenous proteins?
By inserting a gene into an expression vector in a bacterial organism. This is then grown in high densities and purified.
Name some examples of microbial factories
-production of vaccines such as genes for protective antigens, virus components produced in yeast
-Complex vitamins like B12
-Antibiotics e.g. streptomycin
What are some examples of life-changing protein drugs and why are they better now they are grown in microbial factories?
Insulin, Growth hormone, Factor VIII
-Not purified from blood so not contaminated (e.g. HIV)
How are viruses used in gene therapy?
Vectors used for delivery of genes into specific cell types
e.g. bone marrow
RNA version of gene is inserted into retrovirus, within the retrovirus capsid, retrovirus infects bone marrow cells that have been removed from patient, viral DNA carrying normal gene inserts into chromosome and finally inject cells into patient
What are some risks with viral vectors in gene therapy?
-viral vector may recover ability to cause disease
-may load gene near to oncogene (genetic mutations that cause cancer), triggering cancer
-Easier for single-gene defects such as cystic fibrosis
What is an example of a human viral gene therapy success story?
2011, London: 6 patients treated for Hemophilia B
Patients had defect in gene encoding blood coagulation Factor IX
