MICROBIOLOGY

THE POLYMERASE CHAIN REACTION The Polymerase Chain Reaction (PCR) is a technology used to amplify small amounts of DNA. The PCR technique was invented in 1985 by Kary B. Mullis while working as a chemist at the Cetus Corporation, a biotechnology firm in Emeryville, California. So useful is this technology that Mullis won the Nobel Prize for its discovery in 1993, eight years later. It has found extensive use in a wide range of situations, from the medical diagnosis to microbial systematics and from courts of law to the study of animal behavior. The requirements for PCR are: a. The DNA or RNA to be amplified b. Two primers c. The four nucleotides found in the nucleic acid, d. A heat stable a thermostable DNA polymerase derived from the thermophilic bacterium, Thermus aquaticus , Taq polymerase The Primer: A primer is a short segment of nucleotides which is complementary to a section of the DNA which is to be amplified in the PCR reaction. Primers are anneal to the

In recent times giant strides have been taken in harnessing our knowledge of the molecular basis of many biological phenomena. Many new techniques such as the polymerase chain reaction (PCR) and DNA sequencing have arrived on the scene. In addition major projects involving many countries such as the human genome project have taken place. Coupled with all these exciting technological developments, new vocabulary such as genomics has arisen. All this has transformed the approaches used in industrial microbiology. New approaches anchored on developments in molecular biology have been followed in many industrial microbiology processes and products such as vaccines, the search for new antibiotics, and the physiology of microorganisms. It therefore now appears imperative that any discussion of industrial microbiology and biotechnology must take these developments into account. This section will discuss only selected aspects of molecular biology in order to provide a background fo

SOME MICROORGANISMS COMMONLY USED IN INDUSTRIAL MICROBIOLOGY  & BIOTECHNOLOGY: The Actinobacteria: The Actinobacteria are the Firmicutes with G+C content of 50% or higher. They derive their name from the fact that many members of the group have the tendency to form  filaments or hyphae (actinis, Greek for ray or beam). The industrially important members of the group are the Actinomycetes and Corynebacterium.     Corynebacterium s pp are important industrially as secreters of amino acids. The Actinomycetes They have branching filamentous hyphae, which somewhat resemble the mycelia of the fungi, among which they were originally classified. In fact they are unrelated to fungi, but are regarded as bacteria for the following reasons. First they have petidoglycan in their cell walls, and second they are about 1micrometer in diameter (never more than 1.5 ), whereas fungi are at least twice that size in diameter. As a group the actinomycetes are unsurpassed in their abilit

SOME MICROORGANISMS COMMONLY USED IN INDUSTRIAL MICROBIOLOGY  & BIOTECHNOLOGY
: BASIC NATURE OF CELLS OF LIVING THINGS: All living things are composed of cells, of which there are two basic types, the prokaryotic cell and the eucaryotic cell  .The parts of the cell are described briefly beginning from the outside. Cell wall: Procaryotic cell walls contain glycopeptides; these are absent in eucaryotic cells. Cell walls of eucaryotic cells contain chitin, cellulose and other sugar polymers. These provide rigidity where cell walls are present. Cell membrane: Composed of a double layer of phospholipids, the cell membrane completely surrounds the cell. It is not a passive barrier, but enables the cell to actively select the metabolites it wants to accumulate and to excrete waste products. Ribosomes are the sites of protein synthesis. They consist of two sub-units. Procaryotic ribosomes are 70S and have two sub-units: 30S (small) and a 50S (large) sub-units.