Download Intro to Biotechnology Chapter 6 Key Points: 6.1: Sources of

Intro to Biotechnology Chapter 6 Key Points:
6.1: Sources of Potential Products
Plants and animal parts are used for a variety of purposes
a. chewing on willowbark to lesson tooth pain
b. grinding up the pancreas from livestock to obtain the protein insulin for treatment
of diabetes.
c. Use of the foxglove plant to make digitalis, a drug used regulate an irregular heart rate.
Some products are produced in such small amount that it is impractical to harness them from nature.
Ex. t-PA (tissue plasminogen activator) –dissolves blood clots. It is now given to patients after
Heart attacks and strokes to clear blocked blood vessels.
Produced by humans but in too small of a quantity to harvest for commercial purposes.
The gene for the production of t-PA was cloned in Chinese hamster ovary cells (CHO). These cells were
grown in large vats and took up the gene and started producing t-PA in large quantities so it could be
harvested for commercial use by doctors and EMT’s.
Research and Development of a new product:
Need to have a Comprehensive Product Development Plan (CPDP) to determine if developing a
product will be profitable.
Steps involved in a CPDP:
1. Does the product meet a critical need? Who will use the product?
2. Is the market large enough to produce sufficient sales? How many customers are there?
3. Does preliminary data support that the product will work?
4. Can patent protection be secured? Can you prevent others from producing the product?
5. Can the company make a profit? How much will it cost vs how much it can be sold for.
6.2: The use of Assays
Most products headed for development are proteins. Scientists must be able to quantify the amount of
protein being made and the amount of activity that protein has. You must be able to test for its
presence, activity and concentration. In other words, it must be “Assayed”.
Meaning the same as “test”, there are many different assays available.
a. activity assay- shows the protein is present and that it is actively doing what it should be.
b. concentration assay- used to find the amount per unit volume of protein you have. Does not
tell specifics of a protein, just how much there is.
c. Enzyme linked immunosorbent assay (ELISA)- used to find the presence and concentration of
a specific enzyme
ELISAs are so common that many labs have their own ELISA plate washers and readers.
If a substance being developed is a pharmaceutical, it must undergo more extensive testing.
d. potency- used to determine how the dosage will affect its activity.
e. toxicology- show what quantities of the drug are toxic to your cells.
f. stability- determines shelf life and proper storage procedures
Investigational new drug (IND) application to the FDA-assays must be developed the products safety and
efficiancy.
Multispecies pharmacokinetic (PK) assays and pharmacodyamic (PD) assays must be developed and
conducted. These tests show the amount and length of activity of the product in humans as well as in
other organisms such as monkey, mice or rabbits.
6.3: Looking for new products in nature
Scientists estimate there are over 1 million plant species and only 25% have been identified. Most are
found in the equatorial tropical rainforests. How many of these unidentified plants might contan some
chemical that may be of use to humans as a medicine, pesticide, herbicide or other application?
Based on leads from native people or other scienctists, scientists collect hundreds of plant, animal and
fungal samples from the rainforest for testing.
Antimicrobials- substances that kill bacteria and some other microorganisms.
Antibiotics- chemicals that slow the growth or kill microorganisms by interfering with some cellular
process.
Prob lem: some bacteria become resistant to antibiotic. They mutate quickly and, by chance,
become antibiotic resistant.
One test for antimicrobial properties is to put extract soaked paper disks on a agar plate with bacteria
on it. If a halo forms around the disk, it is inhibiting the bacteria growth. (see page 171)
6.4: Studying plant proteins as possible products
Phenotype- the outward appearance of an organism
Ex. round seed, wrinkled seed
Genotype- the genetic makeup inherited from parents
Ex. TT tt and Tt
The phenotype of a plant, tissue or cell is directly related to the proteins it produces. DNA sequence
determines this. If the DNA is altered through genetic engineering, the organism is considered a
genetically modified organism (GMO). Many GMOs are of commercial value.
Ex. roundup-ready soybeans- Modified so they are not killed by the herbicide roundup.
To extract proteins from plant cells is harder due to cell wall. Scientists can grind them up or freeze
them in liquid nitrogen and then crush them. Once cell wall is removed, the process of protein
extraction is similar to most other cells.
Enzymes can be used to break down the cell wall
a. cellulase and pectinase
Once cell wall is gone, you have a protoplast.
These are valuable because it is easy to get DNA into them. Scientists can use a needle or “gene gun” to
put DNA into protoplasts.
Tissuemizer may be used to grind up tissues without causing them to foam up. This eliminates
denaturing of proteins.
If a gel shows evidenc e of a wanted protein, further tests can be done. The isolated protein then can be
directly used for its purpose.
Ex. Bollard cotton (by Monsanto)- contains a neurotoxin protein (originally found in other plants,
which kills insects.
6.5: Producing recombinant DNA (rDNA) protein products
rDNA- Mixing DNA from two sources. First done in the mid-1970’s. When cells take up foreign rDNA,
then read the code and start to produce the protein coded for. The “transformed cell” makes the
protein of interest and can be scaled up to large scale production of the product.
Transformation that occurs in animal cells is called transection. It takes about 15 years to develop, test
and then market a rDNA protein product. FDA testing may take 3-5 years to complete.