Aqrobacterium tumefaciens. for a long time has been doing what molecular biologists are now striving to do. It has been inserting foreign genes into plants and getting the plants to express those genes in the form of proteins. In the process the bacterium causes the plant cells to proliferate and form a gall or tumour, most commonly at or near the junction of the root and the stem. The crown gall is a neoplastic disease of plants caused by Aqrobacterium. The interest in the bacteria stems from its relevance to the cancer problem, that animal and plant cancer have many common characteristics. The disease it induces provides investigators with a model system in which fundamental aspects of bacterial infection, host-parasite relationships as well
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They are derivatives of common metabolic intermediates, for the most part amino acids and various keto acids or sugars. Octopine, a compound of arginine and pyruvic acid and nopaline, a product of arginine and a-ketoglutamic acid, were the compounds studied. Two significant findings were (i) whether a tumour will synthesize octopine or nopaline depends not on the host but on the bacterial strain that induces the tumour and (ii) a given bacterial strains grows on either octopine or nopaline but not both; it can metabolize whichever of the compounds is synthesized by the tumour. Morel proposed that the bacterium must insert into the plant cell a gene governing the synthesis of either octopine or nopaline; the TIP must be DNA.
The following paragraphs outline a review of the existing literature on A. tumefaciens and tumorigenesis.
3
General characteristics of Aqrobacterium tumefaciens
The bacteria are common mesophilic soil inhabitants. They are short gram-negative rods, having or size of 0.6-1.0 p X 1-3 p, are usually motile bearing one to six peritrichous flagella, and
They are derivatives of common metabolic intermediates, for the most part amino acids and various keto acids or sugars. Octopine, a compound of arginine and pyruvic acid and nopaline, a product of arginine and a-ketoglutamic acid, were the compounds studied. Two significant findings were (i) whether a tumour will synthesize octopine or nopaline depends not on the host but on the bacterial strain that induces the tumour and (ii) a given bacterial strains grows on either octopine or nopaline but not both; it can metabolize whichever of the compounds is synthesized by the tumour. Morel proposed that the bacterium must insert into the plant cell a gene governing the synthesis of either octopine or nopaline; the TIP must be DNA.
The following paragraphs outline a review of the existing literature on A. tumefaciens and tumorigenesis.
3
General characteristics of Aqrobacterium tumefaciens
The bacteria are common mesophilic soil inhabitants. They are short gram-negative rods, having or size of 0.6-1.0 p X 1-3 p, are usually motile bearing one to six peritrichous flagella, and