Abstract: A method is provided for regulating the conversion rate of a hereditary trait of a cell, comprising the step of regulating the error-prone frequency of gene replication of the cell. A method is provided for producing a cell having a regulated hereditary trait, comprising the step of (a) regulating an error-prone frequency of gene replication of the cell, and (b) reproducing the resultant cell. A method is provided for producing an organism having a regulated hereditary trait, comprising the steps of (a) regulating the error-prone frequency of gene replication of the organism, and (b) reproducing the resultant organism.

Abstract: This application provides a method for mutagenesis of a gene, which comprises introducing much more point mutations into one strand of double-stranded genomic DNA of cell or organism individual than into another strand. In accordance with such a method, it is now possible to efficiently and effectively construct various useful mutants of microorganisms, cells or organism individuals. It is also now possible by analyzing the mutating conditions of the gene to clarify the mechanism of drug resistance, to estimate the occurrence of a novel insensible microorganism or to develop a drug therefor, to analyze the mutation of an oncogene and the mechanisms of cancer metastasis and increase in malignancy, to develop a therapeutic method using these mechanisms, etc.

Abstract: A method is provided for regulating the conversion rate of a hereditary trait of a cell, comprising the step of regulating the error-prone frequency of gene replication of the cell. A method is provided for producing a cell having a regulated hereditary trait, comprising the step of (a) regulating an error-prone frequency of gene replication of the cell, and (b) reproducing the resultant cell. A method is provided for producing an organism having a regulated hereditary trait, comprising the steps of (a) regulating the error-prone frequency of gene replication of the organism, and (b) reproducing the resultant organism.

Abstract: A method is provided for regulating the conversion rate of a hereditary trait of a cell, comprising the step of regulating the error-prone frequency of gene replication of the cell. A method is provided for producing a cell having a regulated hereditary trait, comprising the step of (a) regulating an error-prone frequency of gene replication of the cell, and (b) reproducing the resultant cell. A method is provided for producing an organism having a regulated hereditary trait, comprising the steps of (a) regulating the error-prone frequency of gene replication of the organism, and (b) reproducing the resultant organism.

Abstract: This application provides a method for mutagenesis of a gene, which comprises introducing much more point mutations into one strand of double-stranded genomic DNA of cell or organism individual than into another strand. In accordance with such a method, it is now possible to efficiently and effectively construct various useful mutants of microorganisms, cells or organism individuals. It is also now possible by analyzing the mutating conditions of the gene to clarify the mechanism of drug resistance, to estimate the occurrence of a novel insensible microorganism or to develop a drug therefor, to analyze the mutation of an oncogene and the mechanisms of cancer metastasis and increase in malignancy, to develop a therapeutic method using these mechanisms, etc.

Abstract: This invention provides A method for preparing mutant genes, which comprises the steps of constructing a recombinant plasmid DNA by inserting a gene fragment into a plasmid DNA having a unidirectional origin, introducing the recombinant plasmid DNA into host cell lacking DNA error-correcting function to transform the host cell, and culturing the transformant cell in a condition that any mutations of the inserted gene is detectable. According to the present invention, diverse mutant genes can be prepared in a short period of time.

Abstract: A method of producing useful substances which comprising propagating in cultured cells or in a host a recombinant Bombyx mori nuclear polydegrosis virus (BmNPV) DNA is disclosed. The BmNPV DNA is produced by recombination with a double-stranded DNA containing (i) a 5'-upstream BmNPV DNA fragment orginally occurring upstream from the structural gene coding for the production of polyhedral protein and also including the promoter region for the structural gene, (ii) a translational start codon and (iii) a gene coding for the production of a useful substance exogenous to the virus, with or without (iv) a 3'-downstream BmNPV DNA fragment originally occurring downstream from the structural gene coding for the production of polyhedral protein.

Abstract: Recombinant Bombyx mori nuclear polyhedrosis viruses having, in the polyhedral protein-encoding structural gene portion of the Bombyx mori nuclear polyhedrosis virus DNA (BmNPV DNA), a structural gene for a desired protein as joined to the whole of or a part of the polyhedral protein-encoding structural gene with or without interposition of a linker base sequence are provided.By propagating the above viruses in silkworm-derived cells or silkworms, fused proteins of a desired protein and the whole of or a part of the polyhedral protein as joined together with or without interposition of a linking amino acid or peptide are produced. The desired proteins can be obtained from the fused proteins by cleavage or decomposition at the linking site.

Abstract: Disclosed is a toxicity test for chemical substances using the phylum Nematoda.According to this test, substances can be easily, rapidly, and inexpensively analyzed for their ability to induce mutations, promote tumor formation, act as teratogens, and cause abnormalities in development, metabolic function, and neuromuscular function.

Abstract: A micromanipulator comprises a miniature operating tool such as a needle, micro-pippet, micro-electrode or the like which is disposed on a movable member of a microscope, such as an illuminating condenser lens, which is movable in the direction of the optical axis of an objective lens.