In this article we will discuss about the organisation of DNA in bacteria. The DNA of bacteria, e.g. E. coli, is a covalently closed circular molecule. It forms the bacterial chromosome, though this chromosome is much simpler in structure and in level of organization than the eukaryotic chromosomes of plants and animals. Also, each bacterial cell normally has a single [...]
The following points highlight the twelve main aspects of mutation and repair of damaged DNA in bacteria. Some of the aspects are: 1. Nature of Bacterial Variations 2. Spontaneous and Induced Mutations 3. Molecular Mechanism of Mutagenesis 4. Physical Mutagenic Agents 5. Mutation Rate and Mutant Frequency 6. Phenotypic Changes Due to Mutation and Others. Aspect # 1. Nature of [...]
In this article we will discuss about selection of different types of mutants:- 1. Resistant Mutants 2. Regulation-Defective Mutants 3. Auxotrophic Mutants. 1. Resistant Mutants: From a wild-type bacterial population which is susceptible to agents like bacteriophage, various drugs, ultra-violet light etc., mutants which are resistant to any of these agents can be selected directly by using selective media. After [...]