Tiêu đề BIOTECHNOLOGY PRINCIPLES & PROCESSES.pdf ✅

 Digital www.allendigital.in [ 27 ] 1. Introduction : • Biotechnology term given by Karl Ereky. • Biotechnology deals with techniques of using live organisms or enzymes from organisms to produce products and processes useful to humans. (A) Old or Traditional Biotechnology: • Based on the natural capabilities of micro organisms. In this sense, making curd, bread or wine, which are all microbe-mediated processes, could also be thought as a form of biotechnology (Early age biotechnology). (B) New or Modern Biotechnology: • Based on Recombinant DNA technology. e.g. Human gene producing Insulin has been transferred and expressed in bacteria like E. coli. However, it is used in a restricted sense today, to refer to such of those processes which use genetically modified organisms to achieve the same on a larger scale. • Further, many other processes/techniques are also included under biotechnology. For example, synthesising a gene and using it, developing a DNA vaccine or correcting a defective gene, all are part of biotechnology. • The European Federation of Biotechnology (EFB) has given a definition of biotechnology that encompasses both traditional view and modern molecular biotechnology. • The definition given by EFB is as follows: (‘The integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services’). • Paul berg (Father of genetic engineering). He transferred gene of SV-40 virus (simian virus) in to E. coli with the help of – phage. (Nobel prize - 1980) 2. Principles of Biotechnology : Among many, the two core techniques that enabled birth of modern biotechnology are: (A) Genetic Engineering/Recombinant DNA Technology : Techniques to alter the chemistry of genetic material (DNA and RNA), to introduce these into host organisms and thus change the phenotype of the host organism. (i.e. formation of genetically modified organism). (B) Bioprocess Engineering : Maintenance of sterile (microbial contamination-free) ambience in chemical engineering processes to enable growth of only the desired microbe/eukaryotic cell in large quantities for the manufacture of biotechnological products like antibiotics, vaccines, enzymes, etc. Biotechnology: 02 Principles and Processes Foreign DNA Genetic modified Organism (GMO)
NEET : Biology [ 28 ] www.allendigital.in  Digital The concept of genetic engineering was the outcome of two very significant discoveries made in bacterial research. These were : • Presence of extrachromosomal DNA fragments called plasmids in the bacterial cell, which replicate independent of chromosomal DNA of the bacterium. • Presence of enzymes restriction endonucleases which cut DNA at specific sites. • These enzymes are, therefore, called ‘molecular scissors’. The conceptual development of the principles of genetic engineering : • The techniques of genetic engineering which include creation of recombinant DNA, use of gene cloning and gene transfer, overcome this limitation and allows us to isolate and introduce only one or a set of desirable genes without introducing undesirable genes into the target organism. Most likely, this piece of DNA would not be able to multiply itself in the progeny cells of the organism. But, when it gets integrated into the genome of the recipient, it may multiply and be inherited along with the host DNA. This is because the alien piece of DNA has become part of a chromosome, which has the ability to replicate. Construction of an artificial recombinant DNA molecule : • The construction of the first recombinant DNA emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid (autonomously replicating circular extra- chromosomal DNA) of Salmonella typhimurium. • Stanley Cohen and Herbert Boyer accomplished this in 1972 by isolating the antibiotic resistance gene by cutting out a piece of DNA from a plasmid which was responsible for conferring antibiotic resistance. The cutting of DNA at specific locations became possible with the discovery of the so- called ‘molecular scissors’– restriction enzymes. • The cut piece of DNA was then linked with the plasmid DNA. These plasmid DNA act as vectors to transfer the piece of DNA attached to it, (A plasmid can be used as vector to deliver an alien piece of DNA) into the host organism. • Recombinant DNA - The linking of antibiotic resistance gene with the plasmid vector became possible with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends. This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA. • When this DNA is transferred into Escherichia coli, a bacterium closely related to Salmonella, it could replicate using the new host’s DNA polymerase enzyme (Enzyme used in DNA synthesis) and make multiple copies. • Cloning - The ability to multiply copies of antibiotic resistance gene in E. coli was called cloning of antibiotic resistance gene in E. coli. The main basis of Recombinant DNA Technology is DNA cloning :- It is making multiple identical copies of any template DNA. Basic steps in genetically modifying an organism (of DNA cloning): (i) Identification of DNA with desirable genes; (ii) Introduction of the identified DNA into the host; (iii) Maintenance of introduced DNA in the host and transfer of the DNA to its progeny.
Biotechnology : Principles and Processes  Digital www.allendigital.in [ 29 ] 3. Tools of Recombinant DNA Technology : • Genetic engineering involves cutting of desired segments of DNA and pasting of this DNA in a vector to produce a recombinant DNA (rDNA). • The ‘biological tools’ used in the synthesis of recombinant DNA include enzymes, vehicle or vector DNA, desired DNA and host cells. (A) Enzymes : • A number of specific kinds of enzymes are employed in genetic engineering. • These include lysing enzymes, cleaving enzymes, synthesising enzymes and joining enzymes. (i) Lysing enzymes - These enzymes are used for opening the cells to get DNA for genetic experiment. • Bacterial cell : is commonly digested with the help of lysozyme. • Plant cell : is commonly digested with the help of cellulase and pectinase. • Fungal cell : is commonly digested with the help of chitinase. Foreign DNA Vector DNA (plasmid) Same restriction enzyme cutting both foreign DNA and vector DNA at specific point Ligases join foreign DNA to plasmid Transformation Cells divide Recombinant DNA E.coli (Cloning Host) Diagrammatic representation of recombinant DNA technology Chitinase (Digests fungal cell wall) Lysozyme (Digests Bacterial cell wall) Cellulase/ Pectinase (Digests Plant cell wall) Lipase (Digests cell membrane) Lysing Enzymes