Microbiology Notes | Biochemistry,Immunolgy,Cell biology

For biotoxification or Biodegradation of toxic substances Required a special enzyme which contain encoded gen on Plasmid Dr. Ananda Mohan Chakrabarty  and his co-workers are isolated a specific organism which is known as Pseudomonas putida in 1989.which can utilize some toxic chemical substances such as 3 chlorobenzene,ethylene etc. Pseudomonas putida  is a Gram-negative, rod-shaped, saprotrophic soil bacterium. V A variety of  P. putida , called multiplasmid hydrocarbon-degrading  Pseudomonas , is the first patented organism in the world. Because it is a living organism, the patent was disputed and brought before the United States Supreme Court in the historic court case  Diamond v. Chakrabarty , which the inventor, Ananda Mohan Chakrabarty, won . P. putida is a multiplasmid containing orgamism which contain more then one plasmid they introduce by genetic engineering different types of plasmid into a cell and forme...

Transposable elements (TEs), also known as “jumping genes” or transposons, are sequences of DNA that move (or jump) from one location in the genome to another. A transposon may be defined as: “a DNA sequence that is able to move or insert itself at a new location in the genome.” The phenomenon of movement of a transposon to a new site in the genome is referred to as transposition. Barbara McClintock’s discovery of these jumping genes earned her a Nobel Prize in 1983. Classification On the basis of their transposition mechanism, transposons may be categorized into following types: ( i) Cut-and-Paste Transposons/Nonreplicative Transposons:   They transpose by excision (cutting) of the transposable sequence from one position in the genome and its insertion (pasting) to another position within the genome Examples: – cut-and-paste type of transposons are IS-elements, P-elements in maize, hobo-elements in Drosophila etc. (ii) Replicative Transpos...

Genetic - Transduction: Definition,Clasification. Definition T ransduction is a process in which involve the genetic element is transfer from a donor bacterial cell to a recipient cell through a bacteriophage. In transduction process the bacteriophage first Infects the donor cell and then carries some genome of donor cell with it,when it Infects another new cell it inject the genome of previous cell into new one. Classification Transduction is classified into two classes – Generalized Transduction Specialized Transduction 1. Generalized Transduction The generalized transduction occurs during the lytic Cycle of viral temperate phage,and it can transfer any part of bacterial chromosome from donor cell to recipient cell. Mechanism Generalized Transduction When the phage infect the host bacterial cell it initiate the lytic cycle. Then this phages are started to synthesis new viral genome, enzymes, capsid, head tail and tail fibers. The enzymes of viral phage...

The  Ames test  is a widely employed method that uses bacteria to test whether a given chemical can cause  mutations  in the DNA of the test organism. More formally, it is a  biological assay  to assess the mutagenic potential of chemical compounds. The test was developed by Bruce N. Ames in 1970s to determine if a chemical at hand is a mutagen. Ames test uses several strains of bacteria ( Salmonella, E.coli ) that carry a particular mutation. Point mutations are made in the histidine (Salmonella typhimurium) or the tryptophan (Escherichia coli) operon, rendering the bacteria incapable of producing the corresponding amino acid. These mutations result in his- or trp- organisms that cannot grow unless histidine or tryptophan is supplied. But culturing His-  Salmonella  is in a media containing certain chemicals, causes mutation in histidine encoding gene, such that they regain th...

Definition Bacterial Transformation is a processes in which a bacterial cell intake a segment of DNA from the environment or other bacteria,and get integrated with it by homologous recombination. Transformation in bacteria was first demonstrated in 1928 by the British bacteriologist Frederick Griffith. IN 1944  Oswald Avery, Colin MacLeod, and Maclyn McCarty experimentally proved that DNA is the main principle involve in gene transformation. Classification Transformation is classified into two classes,this are- Natural Transformation Artificial Transformation. Natural Transformation: Some bacteria can naturally transformable they can take DNA From environment without any special treatment Artificial Transformation: Most of the bacteria are not natural transformable. These bacteria can be made competence by certain chemical treatment or by strong electrical shock. Mechanism of Transformation The transformation mechanism first obser...