Control of growth

Unlike auxotrophic mutants, regulatory mutants can be grown in inexpensive, complex media and they do not require careful control of growth conditions. 

Hi) Poly amines. In many respects the role of poly amines in plant functioning is still mysterious after many years work. They are almost certainly involved in the control of growth and development through their interactions with nucleic acids and membranes (Smith, 1985). There is increasing circumstantial evidence for their involvement, especially of putrescine, in plant responses to a wide range of stresses including pH, Mg deficiency, osmotic shock, cold, SO2 pollution, and cadmium and ammonium toxicity (Smith, 1985). It remains to be determined, however, how, and indeed whether, putrescine accumulation in response to these diverse stresses is beneficial. 

Pritchard, J. (1988). The control of growth rate in wheat seedling roots. PhD thesis. University of Wales. 

Bryant PL Simpson P 1984 Intrinsic and extrinsic control of growth in developing organs. Q Rev Biol 59 387-415... 

Muller E. (1973). Nervous control of growth hormone secretion. Neuroendocrinology 11, 338-69. 

Signal transduction (control of growth factor and MAP-kinase pathways)... 

There is a family of proteins (the Bcl-2 family) that can regulate the potential across the inner mitochondrial membrane, and its permeability. Hence, they can influence apoptosis. Some of this family stabilise the inner membrane and maintain the potential, so that they suppress apoptosis. They are known as cell survival molecules (e.g. the proteins, Bcl-2, Bcl-X). Other members of the family destabilise the mitochondria and decrease the membrane potential which facilitates apoptosis. They are known as cell killer proteins (e.g. the proteins, Bax, Bak). The mechanisms by which they have their effects on mitochondria are not known. They are, of course, of considerable interest for the development and control of growth of tumour cells (See Chapter 21). 

Feruloylated pectins have been found in the parenchymatous cell walls of many Dicotyledons (mainly in the Centrospermae and Solanaceae), but UV-fluorescence microscopy suggests that at least the epidermal cell walls of all Dicotyledons contain phenolic residues it remains to be seen whether these phenolic residues are attached to polysaccharides or to cutin, but location of even a small quantity of, say, feruloyl-pectin in the epidermal wall would be particularly significant in the control of growth because the extensibility of the epidermis controls the expansion of whole stems (23) and leaves (Fry, unpublished observations). The extensins, as already mentioned, are rich in the phenolic amino acid tyrosine (2). 

Oncogene—Gene that can change a normal cell into a cell that fails to respond to the body s normal control of growth and cell division. 

The p53 protein assumes an important role in the control of growth of higher organisms. It functions as a tumor suppressor, that is, it suppresses the growth of tumors (see chapter 14). An inactive, mutant form of p53 is found in nearly half of all human tumors. 

Azarnia R, Loewenstein WR Intercellular communication and the control of growth. X. Alteration of junctional permeability by the sre gene. A study with temperature-sensitive mutant Rous sarcoma virus. J Membr Biol 1984 82 191-205. 

In view of current discussions on a possible role of cell surface saccharides in control of growth and differentiation (1,... 

Lipskaia, L., Lompre, A.M., 2004, Alteration in temporal kinetics of Ca2+ signaling and control of growth and proliferation. Biol Cell 96, 55—68. 

Kentroti S, McCann SM (1996) Role of dopamine in the inhibitory control of growth hormone and prolactin release by gastrin-releasing peptide. Brain Res Bull 39 201-204. 

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