PHA inclusions

Fig. 2. Accumulation of PHA inclusions in Arabidopsis transgenic plants. Transgenic cell expressing the poly(3HB) pathway in the plastid showing accumulation of poly(3HB) inclusions (arrows) in the chloroplast of a leaf mesophyll cell. Bar represents 1 pm... 

PHA beads have been demonstrated for their utility to purify proteins implementing two very different approaches. One approach uses the production of recombinant target proteins as fusion proteins to be attached to the surface of PHA inclusions during formation and the second approach considered PHA beads which display a binding domain with binding affinity to the target. 

PHA bead-based fusion protein purification strategies have utilized fusions of the target protein to proteins naturally associated with PHA inclusions such as phasins, regulatory, or synthase proteins. Banki et al. [74] used a phasin-intein target protein fusion to anchor the fusion protein to the PHA granule as it forms... 

Only recently, PHA inclusions were developed to display specific antigens of pathogenic mycobacteria for use as skin test [80]. The PHA inclusions outperformed existing commercial offering in animal experiment and is currently be tested in large-scale field trails. 

Mayer, E, Madkour, M.H., PieperFurst, U., Wieczorek, R., Gesell, M.L., and Steinbuchel, A. (1996) Electron microscopic observations on the macromolec-ular organization of the boundary layer of bacterial PHA inclusion bodies. /... 

Mayer, F. and Hoppert, M. (1997) Determination of the thickness of the boundary layer surrounding bacterial PHA inclusion bodies, and implications... 

The second phase of research [283] has focused on the targeting of the PHA pathway to a specific subcellular compartment, the plastid, where biosynthesis of triglycerides from acetyl-CoA normally occurs. All three genes needed be cloned in this case, and this led to the accumulation of high levels of PHB with few deleterious effects on the growth or fertility of the hosts. The homopolymer was stored within plastids to up to 14% of the dry mass of the plants (a 100-fold increase from expression in the cytoplasm) in the form of granules of size and appearance similar to those of bacterial PHA inclusions. 

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