Tissue culture techniques, general

Tissue culture techniques generally require very exacting media with numerous components and are often plagued by bacterial contamination. A recent interest in the use of cultured hepatocytes as models for metabolism offers some advantages, but still requires a tedious procedure of perfusion of a section of liver and seeding of isolated hepatocytes in a complex nutrient medium, followed by daily maintenance of the cultures [25]. 

Compared with whole plants, there has been limited development of foreign protein expression systems specifically for use in tissue culture. Some modifications of expression constructs have resulted in improved protein accumulation or have allowed simplified protein recovery. However, in general, modified expression systems have been tested only in a restricted number of cases and have not resulted in the large increases in product yield required for plant cultures to compete with other foreign protein production vehicles. Transient expression techniques, for example using viral vectors, that have been developed for use in whole plants have not yet been applied in plant tissue culture. 

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