Genetic manipulations

R. W. Old and S. B. Primrose, Principles of Genetic Manipulation Mn Introduction to Genetic Engineering, University of California Press, Berkeley, 1985. 

D. A. Hopwood and co-workers, ia Genetic Manipulation of Streptomjcetes A. Eaboratoy Manual, ]ohxs limes Foundation, Norwich, UK, 1985. 

Other macrohdes have been prepared which represent hybrids of stmctures within the 14-membered family, within the 16-membered family, or between the two families. These hybrids have been made by chemical, bioconversion, or genetic manipulations. The 9-0-[(2-methoxyethoxy)methyl]oxime of tylosin (Table 7) was synthesized, using the oxime found in roxithromycin (33) (369). 3-0-Cladinosyl derivatives of 16-membered macrohdes were synthesized in which the neutral sugar of erythromycin (Table 3) was attached to tylosin derivatives at thek 3-hydroxyl group, analogous to its position in erythromycin... 

Development of new yeast strains through genetic manipulation techniques has shown some interesting results. Strains with, eg, beta-gluconase activity are produced and have proven satisfactory. 

Genetic manipulation or cloning offers many possibiUties and perhaps there will be yeast strains especially designed for special beers, ie, types, which are usehil because of low diacetyl formation, high—low ester formation, and insensitivity to pressure or high fermentation temperatures or extracellular enzymatic abiUties (P-glucanases). 

Through genetic manipulation, com cultivars with altered starch compositions have been developed. Various modified and detivatized starches are... 

Potential consumer benefits from biotechnology (56) are cost and quaUty. The use of biotech means to increase the level of various sulfur-containing amino acids in coffee proteins, and to enhance sucrose and oil levels, could have an impact on the flavor and aroma of the finished ground coffee product. Also, caffeine level modification/elimination through genetic manipulations of the coffee plant could yield low caffeine coffee without additional processing by the manufacturer. 

Consideration of pencillin production serves to illustrate the success of these strategies. Penicillin was produced at a concentration of about 1 ppm by the first penicillin producers that were isolated. By manipulation of culture conditions together with genetic manipulation, yields in excess of 10 g l 1 (excess of 10,000 ppm) are routinely achieved. This development has also been paralleled by the diversification of the... 

Under natural conditions. Agrobacterium does not appear to infect monocotyledonous plants. Genetic manipulation of cereal crops using a Ti-plasmid delivered by Agrobacterium therefore seems out of the question. However, there are some data to suggest that Agrobacterium can, under certain circumstances, infect monocots, but that it does not cause... 

The refractory nature of some pollutants, notably, persistent polyhalogenated compounds, has raised problems of bioremediation of contaminated sites (e.g., sediments and dumping sites). There has been interest in the identification, or the production by genetic manipulation, of strains of microorganisms that can metabolically degrade recalcitrant molecules. For example, there are bacterial strains that can reductively dechlorinate PCBs under anaerobic conditions. 

It is generally accepted (based on clinical and in vitro studies) that mast cells (and basophils), IgE and FceRI are involved in most cases of allergen-induced anaphylaxis in humans. However, it is difficult to define the exact roles and relative importance of mast cells, basophils, and other potential effector cells (e.g monocytes/macrophages, dendritic cells) in either IgE-dependent or IgE-independent human anaphylaxis. Unlike in mice, we neither have access to mast cell- or basophil-deficient humans nor can we genetically manipulate human subjects to produce such phenotypes. 

In recent years, our detailed understanding of the structure of DNA and how it functions has led to many new methods of genetic manipulation. Our Box explores one aspect of this subject. 

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