Abstract: The present invention describes the use of thio-phosphate in the metabolic engineering of E. coli. Thio-phosphate can be used to increase the metabolic flux in important synthetic pathways to enhance the production of bioproducts. The pathways impacted include the following: fatty acid synthesis, isoprenoid syntheses, Vit K2 synthesis, ribonucleotide synthesis, and the synthesis of phosphoribosyl pyrophosphate (PRPP) derivatives like 5-aminoimidazole-4-carboxamide (AICA riboside), histidine, and tryptophan. Thus, thio-phosphate can be used to assist in the production of these molecules and/or their derivatives. Enhanced production of AICA in Bacillus megaterium is also demonstrated.

Abstract: The present invention describes the use of thio-phosphate as a novel metabolite for chemically modifying mRNA in cells. Thio-phosphate is taken up by both prokaryotic and eukaryotic cells, incorporated into rNTP pools and ultimately mRNA. This enables the in vivo modification of mRNA with nuclease resistant phosphorothioate internucleotide linkages. Significant incorporation of thio-phosphate occurs such that RNA is significantly stabilized from degradation both in vivo and in vitro upon subsequent isolation. Thio-phosphate can be used as the sole source of phosphate in the culture medium for several generations resulting in a significant increase in the amount of mRNA per cell. The method should facilitate the detection and analysis of mRNA for research and diagnostic purposes. To enhance protein production it is necessary to use a mixture of thio-phosphate and phosphate in the culture medium.

Abstract: Methods are presented for enhancing the natural mutation rate of micro-organisms, particularly bacteria via a modified phosphate. The novel metabolite inhibits DNA repair mechanisms in vivo resulting in a 100-200 hundred fold increase in the mutation rate of bacteria. The method yields viable cells and allows for the continuous selection of incremental traits. The modified phosphate can also be used to randomly mutate specific genes. In particular, high rates of random mutagenesis can be readily achieved in vivo using recombinant DNA phage. The phage are amplified in mutator media containing the modified phosphate. The resultant phage can be further mutated by another round of infection and growth in mutator media. After two such rounds of amplification significant mutation rates are achieved such that each phage insert bears a novel mutation. The mutator media can also be used to mutagenize recombinant DNA plasmids in virtually any bacterial host.

Abstract: The present method describes the use of thio-phosphate as a feed source for micro-organisms and multi-cellular organisms. This compound enters into nucleotide pools and ultimately into polymers of both RNA and DNA forming stable phosphorothioate internucleotide linkages. The method enables the microbial synthesis of both plasmid and phage DNA substituted with phosphorothioate. Furthermore, methods are described for the preparation of phosphorothioate oligo mixtures from recombinant phage DNA grown in modified media for use in antisense studies.

Abstract: The present invention describes a method for the detection of single base-pair DNA sequence variation in DNA samples isolated from cells with limited ploidy (1.sup..about. 3N). The method can detect variation essentially anywhere in the genome. The method comprises identifying single base-pair polymorphisms or mutations by amplifying a specific region of genomic DNA using a polymerase chain reaction, denaturation of the resultant chains followed by renaturation to form a heteroduplex or hybrid DNA molecule containing one or more single base-pair mismatches. The heteroduplex is then digested with S1 nuclease and the products separated by size with detection by Southern Blot, the use of labeled primers or sensitive gel staining. The method should be generally useful as a simplified approach to identify DNA sequence variants in a variety of samples. It also provides a potentially powerful approach to genetic mapping, DNA fingerprinting, disease detection, and population genetics.