Biotech

• Ever since the days of Rene Descartes, the French philosopher, mathematician and biologist of seventeenth century, all human knowledge especially natural sciences were directed to develop technologies which add to the creature comforts of human lives, as also value to human life
• The whole approach to understanding natural phenomena became anthropocentric
• Physics and chemistry gave rise to engineering, technologies and industries which all worked for human comfort and welfare
• The major utility of the biological world is as a source of food
• Biotechnology, the twentieth century off-shoot of modern biology, changed our daily life as its products brought qualitative improvement in health and food production
• The basic principles underlying biotechnological processes and some applications are highlighted and discussed in this unit
• Herbert Boyer was born


  1936
• Herbert Boyer was brought up in a corner of western Pennsylvania where railroads and mines were the destiny of most young men
• In 1963, Herbert Boyer completed graduate work at the University of Pittsburgh, followed by three years of post-graduate studies at Yale
• In 1966, Boyer took over assistant professorship at the University of California at San Francisco
• By 1969, Boyer performed studies on a couple of restriction enzymes of the E. coli bacterium with especially useful properties
• Boyer observed that these enzymes have the capability of cutting DNA strands in a particular fashion, which left what has became known as 'sticky ends' on the strands
• These clipped ends made pasting together pieces of DNA a precise exercise
• This discovery, in turn, led to a rich and rewarding conversation in Hawaii with a Stanford scientist named Stanley Cohen
• Cohen had been studying small ringlets of DNA called plasmids and which float about freely in the cytoplasm of certain bacterial cells and replicate independently from the coding strand of DNA
• Cohen had developed a method of removing these plasmids from the cell and then reinserting them in other cells
• Combining this process with that of DNA splicing enabled Boyer and Cohen to recombine segments of DNA in desired configurations and insert the DNA in bacterial cells, which could then act as manufacturing plants for specific proteins
• This breakthrough was the basis upon which the discipline of biotechnology was founded
• Biotechnology


  Techniques of using live organisms or enzymes from organisms to produce products and processes useful to humans
• Making curd, bread or wine, which are all microbe-mediated processes, could also be thought as a form of biotechnology
• Biotechnology 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
• Processes/techniques included under biotechnology

  • In vitro fertilisation leading to a 'test-tube' baby
  • Synthesising a gene and using it
  • Developing a DNA vaccine
  • Correcting a defective gene
• Definition of biotechnology by the European Federation of Biotechnology (EFB)

  The integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services
• Two core techniques that enabled birth of modern biotechnology

  • Genetic engineering
  • Maintenance of sterile (microbial contamination-free) ambience in chemical engineering processes
• Genetic engineering

  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
• Asexual reproduction


  Preserves the genetic information
• Sexual reproduction

  Permits variation
• Traditional hybridisation procedures used in plant and animal breeding, very often lead to inclusion and multiplication of undesirable genes along with the desired genes
• 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, a piece of DNA transferred into an alien organism would not be able to multiply itself in the progeny cells of the organism
• When the alien piece of DNA gets integrated into the genome of the recipient, it may multiply and be inherited along with the host DNA
• Origin of replication

  A specific DNA sequence in a chromosome that is responsible for initiating replication
• For the multiplication of any alien piece of DNA in an organism it needs to be a part of a chromosome(s) which has a specific sequence known as 'origin of replication'
• This can also be called as cloning or making multiple identical copies of any template DNA
• 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
• Restriction enzymes

  Molecular scissors that cut DNA at specific locations
• The cut piece of DNA was then linked with the plasmid DNA
• Plasmid DNA

  Act as vectors to transfer the piece of DNA attached to it
• 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