Theory of spontaneous and Biogenesis.

Theory of spontaneous generation/concept of abiogenesis.

this is the concept that believes upon the inanimate organization of living beings.Most of the Greek Philosopher including astute Aristotle in the 4th century where the greater supporter of abiogenesis.Many scientists performed experiments to prove that life comes from nonliving environmental factors like water,soil etc.

1. Virgil(70-19 BC)in about 40BC performed an experiment to show that bees can be originated artificially.
2. John Needham(1713-1781) performed an experiment to show that maggots can be prepared from meat.
3. Felix Archimede pouches (1800-1872)published the exxtensive report in support of abiogenesis.

Theory of Biogenesis.

Biogenesis is the concept in which life can only originate from some other primitive forms of life present in the environment but not inanimate objects.this concept explain the origination of cell can only happen from a cell or life comes from life.there were many assumptions,postulations, and experiment regarding support of biogenesis:

1. Francisco Redi(1688) performed an experiment with boiled beef broth and non-boiled beef broth in a closed and open jar to verify the theory of biogenesis.
2. Lazzaro Spallanzani(1729-1799)performed the experiment of boiled and nonboiled beef broth by keeping both in a closed flask for the long period of time and reported no growth in beef broth.
3. Fram Schulze(1815-1873)passed air through strong acid solution into the infusion and reported no growth.
4. Theodore Schwan (1810-1882)passed air through the red hot tube into beef broth and reported no growth.
5. H.Schroder and T.von Dush performed an experiment by passing air through cotton fibres that filtered the microorganisms present in the air and reported no growth.Based on his experiment cotton blogging was started in the microbiological laboratory.

Louis Pasteur contribution

Louis Pasteur snecked an idea to prove the theory of biogenesis without treatment of air.He designed a special flask joined to gooseneck like a U-shaped tube for the entrance of air into the flask.Then he kept sterile broth in the flask and passed air through gooseneck tube.Due to sedimentation of the dust particle in the bottom of U-shaped turning of the tube, the pure air entered into the flask due to which no microorganisms were seen in the flask throughout a month long experiment.Later, he passed the air directly from normal tube where microorganisms developed soon.So he concluded that dust particles present in the air carry microorganisms which were responsible for visible growth in beef broth.microorganisms of life can only come from the previous primitive form of life .After his experiment,most of the scientist agreed theory of biogenesis that explains the biogenetic organisation of life.for hs contribution Pasteur was later honoured as "Father of Microbiology".Theory of biogenesis came real understanding in 1864AD after.

Koch's Postulates.

Robert Koch studied the disease anthrax of cattle and formulated few criteria.These criteria provide the guideline to identify the causative agents of infectious diseases.These criteria which are called as Koch's postulates are given below:

• A specific organism is always found associated with a particular disease.
• This organism can be isolated from diseased individual and can be grown in pure culture in the lab.
• The pure culture produces the disease when inoculated into a sceptical healthy individual.
• The organisms can be re-isolated from experimentally infected individual and can be cultured in the lab.
• Specific antibodies should be demonstrated in the serum of patient suffering from the disease against this organisms.

Germ theory of disease.

The concept that microorganisms are the cause of a disease is called germ theory of disease. There are two types of disease,one is infectious and the other is non-infectious.eevery infectious disease is caused by infection of particular microorganisms.One microorganism causes the same type of disease in all sceptical individual.So all individual shows same signs and symptoms if the same microorganism is involved in infection.

Microorganisms can be isolated from disease individual and can be cultivated in pure culture in the lab.If such pure culture is inoculated into other sceptical individual,it can cause the same type of diseases.this finding suggests that transmission of disease from one individual to other is due to the transmission of microorganisms.If transmission of microorganisms is blocked,disease transmission can be prevented.Establishment of the germ theory of disease gave the idea about the route of transmission of disease and their preventive measures. pastures success in solving the problem of fermentation and to request that investigation pebrine.

The contribution of E.jenner in the field of Immunology.

Edward Jenner has given great contribution in the field of immunology.for the first time, the vaccinationwvaccination was done by E.Jenner in 1798.He isolated the fluid from the cow which was infected with small[pox disease.Then he innoculated the old culture of this fluid into child named James Philips.He found that after innoculation, the child became ressistant to the small pox infection.The vaccination practise applied several years ago.E.Jenner experiment suggested that when inactivated organisms is innoculated become resistant to the same organisms in the future.Therefore the word 'vaccination'is derived from the Jenner experiment.i.e vacca means cow in latin language.

Contribution of A.Flemming in the field of Microbiology.

Alexander Flemming is famous for discovery of antibiotic penicillin.In 1992 hureuse did one experiment.He cultivated the Staphylococcus aureusin the nutrient agar plate.His agar plate was contaminated with a mold he noticed that there was a clear zone around the mold.he thought that mold inhibited the growth of bacteria.So,there was no bacterial growth around the mold.Then he did analysis of this mold.He found that mold was Penicillum notatum.P. notatumhad produced one anti-bacerial chemical which inhibited the growth of bacteria.he named this substance as 'penicillin' from the name of mold.later penicillin became very useful to prevent wound infection.this was the first antibiotics developed.this leads too the discovery of many antibiotics by other scientist.

Refrence.

C.H.Collins. (1995). Microbiological Methods. Oxford Univ Press.

D.Greemwood, R. S. (2002). Medical Microbiology. London: Churchill Livingstone.

M.J.Pelezar. (1993). Microbiology. Tata McGraw hill.

M.T.Madigan, J. a. (1997). Biology of microorganisms. London: Prentice hall International Inc.

R.N.Atlas. (1984). Fundamentals and Applicatins. NewYork: MacMiHiam PUblishing Co.