Genetically engineered containment

Thaumatin. Thaumatin [53850-34-3] is a mixture of proteins extracted from the fmit of a West African plant, Thaumatococcus daniellii (Beimett) Benth. Work at Unilever showed that the aqueous extract contains two principal proteins thaumatin I and thaumatin II. Thaumatin I, mol wt 22,209, contains 207 amino acids in a single chain that is cross-linked with eight disulfide bridges. Thaumatin II has the same number of amino acids, but there are five sequence differences. Production of thaumatins via genetic engineering technology has been reported (99). 

Recombinant DNA, this is DNA containing new genetic material in an order different from the original. Genetic engineering can be used to do this deliberately to produce new proteins in cells. 

The blastocyst is an early embryonic stage in mammalian development. Murine blastocysts can be harvested at day 3.5 p.c. Their inner cell mass contains embryonic stem cells. Multiple murine embryonic stem cell lines have been established. Embryonic stem cells carrying genetically engineered mutations are injected into blastocysts, which are subsequently implanted into pseudopregnant foster mothers. 

Dornase alfa is produced by genetically engineered Chinese Hamster ovary cells containing DNA encoding for the native human protein deoxyribunuclease I. It is purified by tangential flow filtration and column chromatography. 

Fig. 3. One of the experimental systems in common use for genetic engineering of plants with Agrobacterium containing a recombinant Ti-plasmid (from Bryant, 1988).

Leaf discs are floated on a suspension of Agrobacterium ceWs that contain genetically engineered Ti-plasmids. The bacterium infects cells around the edges of the discs, and the T-DNA is transferred to the chromosomes of the infected cells. 

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