True or False?

Proceesing, shelf-life, nutritional quality and reduced anti-nutritional characteristics are known as QUALITY TRAITS

oils

proteins: parmaceuticals, vaccines

polymers, plastics

Herbicide tolerance (HT) glyphosate resistance

and

Insect resistance (Bt)

soyabean, maize and cotton are the 3 main GM species

A broad-spectrum herbicide

it works by inhibiting a choloroplast enzyme (EPSP synthase) required for aromatic amino acide synthesis

advantages - enhances crop productivity

< soil erosion

< fuel costs and greenhouse emissions

encourages a 'no-till' agriculture

increased use of Roundup® but reduced use of other herbicides

possible reduction in biodiversity?

Bacillus thuringiensis (Bt)

the spores were first used commercially in 1938 and still used by organic farmers. very specific so not toxic to other animals and environmentally friendly

here are the first few steps in how Bacillus thuringiensis kills larva.

1. lava consumes toxin

2. crystals solubilised and toxin activated by proteolytic cleavage in mid gut

3.toxin binds to specific receptors

describe the final 2 steps

4. binding triggers cell death in mid-gut lining

5. septicaemia follows and larva dies

True or False?

different cry genes target different groups of insects

true

eg cry1Ab kills Lepidoptera

one of the most common Bt maize varieties (MON810) carries the cry1Ab gene which confers resistance against European stem borer

• reduced financial costs due to less pesticide use
• reduced environmental impact of chemical pesticides
• improved health of farmers
• improved food quality due to reduction in fungal toxins

selection pressure for resistant pests

possible effect on non-target insects (controversial)

cspB = cold shock protein from Bacillus subtillis

it belongs to a class of RNA-binding proteins known as RNA chaperones that stabilise mRNA.

when over expressed in a variety of plant species it confers increased tolerence to drought, heat, cold and stress

cspB - it was approved for release in the US in late 2011

MON87460 shows reduced yield loss relative to conventional corn under water-limiting conditions

what is vitamin A?

where do humans obtain their Vitamin A from?

vitamin A (retinol) is a pigment of the eye and the acid retinoic acid is a growth hormone

humans get vit A from plants (B carotene) in the form of provitamin A. this gets converted into Vit A in intestine and liver

animal products containing vitamin A eg, milk, liver and eggs 

night-blindness, xerophthalmia (dry eyes)

VAD is associated with increased susceptbility to death from childhood diseases

severe public health problem in developing countries

124 million children worldwide suffer from VAD

1 to 2.5 million childhood deaths annualy

vit A tablets are effective but expensive and difficult to administer in developing countries on a large scale

the low vitamin A content in rice. it is the staple diet for over 2billion of the 6billion people in the world

polished rice contains little or no B carotene

4 

Geranyl geranyl pyrophosphate (GGPP) 

(phytoene synthase)

Phytoene

(phytoene desaturase)

zeta-carotene

(zeta carotene desaturase)

Lycopene

(lycopene cyclase)

B-carotene baby!

Daffodils - this gave 1.6 ug B-carotene/g

A second version GR2 has higher levels of B carotene. This was made using Phytoene synthase from maize giving 37ug B carotene/g

True or False?

there will be no fee for the humanitarian use of Golden rice and farmers will be permitted to keep and replant the seed

True. As long as the farmer makes <$10,000 per year from its use.

Golden rice is incorporated into rice breeding programs in Philippines, India, Bangladesh, China and Vietnam

GR2 contains enough B- carotene in 72g dry rice to provide 50% of a childs RDA of Vitamin A

Edible vaccines

advantages of this are:

• production highly efficient and can be scaled up
• no refrigeration required, can be stored near site of use and no needles required
• appropiate for developing countries where production storage and transport is difficult

list the rest of the steps in developing an edible vaccine for measles (MV)

1. select an antigen

2. isolate the MV-H gene (measles virus haemagglutinin)

3. express the MV-H gene in edible transgenic plant eg. lettuce

4. test effectiveness by feeding MV-H lettuce to mice

5. Assay for the presence of anti MV-H antibodies in the mice

true or false?

edible vaccine expression in plants has been demonstrated for antigens against cholera, rabies, norwalk virus and hep B

true - also an edible vaccine conferring dual immunity against cholera and malaria has recently been reported

at least 3 human trials have shown potential effectiveness of edible vaccines

Night blindness

Dry eyes