Introduction to Microbiology
Micro-organisms as the name suggests are microscopic in size.Their small dimension is not the only reason for placing them in a special group,but they also have special form,activity, metabolism, ecological distribution and manipulation in laboratory.
Practical importance of micro-organisms has been well established by the damage they cause to man,animal and plants.
Their application ranges from processing of primary agricultural products to catalysis of very important complicated chemical reactions. Example: wine and beer production, glycerol production, dairy products,propanol,lactic acid,citric acid fermentation, butanediol.
New era developed with the discovery of antibiotics medical and pharmaceutical industry. Penicillin and other secondary products have provided powerful tools against infection by bacteria's.Viral infections and tumor viruses can be tackled by these antibiotics. Enzymes like amylases,pectinases,hydrolases and other by-products can be obtained from microbial cultures.
Developments in recombinant DNA technology have opened up the possibility of transferring foreign DNA into bacteria. These bacteria can be exploited as minibiofactories for production of large variety of molecules. These molecules can be proteins associated with benefit of mankind. Example, protein for therapeutic use(insulin), for resistance against pests(B.t. technology), diagnosis of diseases (probes), for vaccines against diseases, or altered sequences of DNA,RNA.
Thus it is leading a new era of biological evolution and use of microbes.
Milestones for development of Microbiology as a discipline
Physician of Italy Girolamo Fracastoro suggests that invisible organisms may be involved in disease.
Zacharias Janssen,an optician from Dutch invents compound microscope.
Using reflected light Robert Hooke explores living and non living things by a compound microscope.
Antony van Leeuwenhoek observes bacteria and protozoa by simple microscope which was designed by him.
A vaccine for smallpox is introduced by Edward Jenner.This lays foundation for immunisation.
25000 human are inoculated by Phillips Ricord to demonstrate that gonorrhea and syphilis are separate diseases.
Theodor Schwann andatthias Schleiden formalize theory that all living things are composed of cells.
He institutes first use of antiseptics to reduce diseases by hand.
John Snow demonstrates epidemic spread of cholera through water contaminated with human sewage.
Louis Pasteur shows fermentation is due to microorganisms and demonstrates pasteurization.
Rudolf Virchow introduces that all cells originate from preexisting cells.
Louis Pasteur condemns theory of spontaneous generation by definitive experiments.
Joseph Lister publishes first work on antiseptic surgery,a beginning towards aseptic techniques in medicine.
Johann Miescher discovers there is complex acid in cell nucleus.He terms it nucleon(DNA,RNA).
Robert Koch studies anthrax in cattle and tells Bacillus anthracis as its causative agent.
Pasteur develops vaccine for anthrax in animals.Robert Koch introduces use of pure culture techniques for bacteria handling in lab.
The causative agent of tuberculosis is identified by Koch.
Koch postulates establish that a disease is caused by a microorganism.
A vaccine for tabbies is developed by Pasteur.
Julius Petri adapts 2 plates for holding media and culture microbes.
Emil con Behring and Shilbasaburo Kitasato demonstrate antibody in serum that neutralize toxins of tetanus and diphtheria.
D.Ivanovski isolates a virus(tobacco mosaic virus) and shows its transmission through cell-free filtrate.
Jules Bordet discovers anti microbial power of complement.
Ross and Grassi demonstrate malaria is transmitted by female mosquito.
Walter Reed clarify role of mosquito in transmitting yellow fever.
James Wright demonstrate presence of antibodies in blood of immunized animals.
Syphilis is caused by Treponema pallidum shown by Schaudinn and Hoffman.
Ehrlich pioneers modern chemotherapy by developing salvarsan,to treat syphilis.
Francis Rous discovers viruses that can induce cancer.
Twort and Herelle discover bacterial viruses.
Frrederick Griffith discovers transformation in bacteria and lays foundation for modern molecular genetics.
Alexander Flemming discovers,describes properties of first antibiotic, penicillin.
Gerhard Domagk discovers first sulpha drug and paves way for anti microbial chemotherapy.
Oswald Avery,Colin MacLeod,Maclyn McCarty show DNA is the genetic material.
Jonas Salk develops first polio vaccine.
Gerald Edelman and Rodney Porter determine structure of antibodies.
Paul Berg develops first recombinant DNA in test tube.
Milstein, Kohler and Kai Berne developed technique for making monoclonal antibodies.
Human insulin is synthesized using genetically engineered bacterium.
First hepatitis B vaccine is developed from virus isolated from human blood.
Montagnier and Hello isolate and characterize HIV.
Susumu Tonegawa work out molecular genetics of antibody genes.
Bishop,Huber and Michel characterize cancer causing genes.
Development of transgenic animals to synthesize haemoglobin of human.
Isolation of human breast cancer gene.
Microbiology: Scope and Relevance
Microorganisms are found almost everywhere. They affect humans in countless ways.It has great impact on science of food,medicine,ecology, agriculture, genetics, biochemistry.
Many microbiologists are interested in the biology of microorganisms and are called virologists, algologists,Protozoologists,mycologists(fungi), bacteriologists.
Others may be interested in morphology and functional process like microbial cytology,ecology,physiology, genetics, taxonomy.
There may be public health microbiology, food and dairy microbiology.
Medical microbiology deals with human and animal diseases. Medical microbiologist identify the agent and plan strategies to eliminate it.
Public health microbiologists control spread of communicable diseases.
Immunology is an important aspect of microbiology related to human welfare. It is concerned with protecting the body from pathogens. It is one of the fastest growing areas in science.
Agricultural microbiologists try to combat diseases of plants.
Microbial ecologists study relationship between microorganisms and habitat.
Food and dairy microbiologists try to prevent food spoilage and transmission of food borne diseases as botulism.
Microorganisms are used to make antibiotics.
Microbial genetics, molecular biology focus on genetic information and its regulation of function of cells.
With genetic engineering microbiology will expand in future.