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 [...]
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 [...]
The following points highlight the seven important transposable elements found in bacteria. The transposable elements are: 1. Insertion Sequences 2. Transposons 3. Cointergration Model of Transposition 4. Conjugative Transposons 5. Integrons 6. Transposon Mutagenesis 7. Transposing Bacteriophage Mu. Transposable Element # 1. Insertion Sequences (IS-Elements): The insertion sequences are the simplest form of transposable elements found in prokaryotes. They were [...]