Chemotherapy:

•  There are two types of chemotherapeutic agents: synthetic drugs and antibiotics.

•  Elrlich (1910) introduced an arsenic containing chemical called Salvarsan to treat Syphilis.

•  Alexander Fleming (1928) – observed that the mold Penicillium inhibited the growth of bacteria and named the active ingredient as penicillin. Penicillin has been used clinically as an antibiotic since the 1940s. Domagk and others developed sulfa drugs.

•  Waksman and others developed Streptomycin and other antibiotics derived from soil organisms.

•  Researchers are tackling the problem of drug-resistant microbes.

 

Genetics and Molecular Biology:

•  1900 – Modern genetics began with the rediscovery of Gregor Mendel's principles of genetics.

•  Frederick Griffith (1928) - discovered that previously harmless bacteria could change their nature and become capable of causing disease

•  Avery, McCarty and MacLeod (1940's) – showed that this genetic change was due to DNA. After this finding came the crucial discovery of the structure of DNA by Watson and Crick

•  Edward Tatum and George Beadle – studied biochemical mutants of Neurospora to show how genetic information controls metabolism.

•  Barbara McClintock (1950) – discovered that some genes could move from one location to another on a chromosome.

•  Early 1960's witnessed a further explosion of discoveries relating to the way DNA controls protein synthesis.

•  Francois Jacob and Jacques Monod (1961) – discovered mRNA and later made the first major discoveries about regulation of gene function in bacteria.

•  Microorganisms can now be genetically engineered to manufacture large amounts of human hormones and other urgently needed medical substances.

•  Late 1960's Paul Berg showed that fragments of human or animal DNA that code for important proteins can be attached to bacterial DNA. The resulting hybrid was the first example of recombinant DNA.

Tomorrow's history:

Microbiology has been in the forefront of research in medicine and biology and continues to play a role in Genetic engineering and Gene therapy.

Genetic engineering – scientists are attempting to redesign microorganisms for a variety of purposes (drugs, hormones, vaccines and a variety of biologically important compounds)

rDNA technology – enabling us to produce improved varieties of plants and animals such as pest-resistant crops and may even enable us to correct genetic defects in human beings.