CONCEPT OF MICROBIOLOGY

                                    Concepts of microbiology

Theory of spontaneous  generation	Germ theory of fermentation	Germ theory of pasteurization	Germ theory of disease
Formation of life from non-living substances.	Anaerobic enzymatic conversion of organic compounds.	It is the process in which heating milk or wine or other liquids so moderate temperature for a definite time, which kills pathogenic bacteria and delays other bacterial growth.	This theory states that infectious diseases are caused by microbes.
It is also called abiogenesis theory.	Ex- ethyl alcohol producing energy in the form of ATP is called fermentation.	This process was originally introduced by Louis Pasteur in 1866 to sterilize wine.	Robert Koch (1876) showed that certain microbes cause disease. He proved that Bacillus anthracis causes anthrax.
Theory disproved by Redi (1650).	Louis Pasteur defined fermentation as life without air. He proved that microorganisms are involved in fermentation.		Fracastoro suggested that disease might be due to invisible organisms transmitted from one person to another.
Spallanzani and Pasteur proved that microorganisms cannot arise spontaneously.	Theodore schurann (1836) demonstrated that yeast causes fermentation and produces alcohol.		Von plenciz (1762) stated that living agents are the cause of disease and suspected that different germs were responsible for different disease.
Louis Pasteur and others said that life  originated from pre- existing life only. This concept called biogenesis	Edward Buchner (1897) showed that extracts of  Yeast cells could produce alcoholic fermentation.		Oliver Wendell Holmes (1809-1894) insisted  That puerperal fever, a disease of childbirth caused by a germ carried from one mother to another by midwives and physicians.
	Pasteur demonstrated that specific microorganisms were required for alcoholic, lactic, butyric and other fermentation. This is called germ theory of fermentation.

GROWTH FACTORS OF SERUM

                                                      Growth factorsof serum

In animal cell culture system invitro condition cultured cell undergo divisions only when blood serum is added to the medium. Serum means liquid portion of  the blood without fibrinogen.

These serum proteins were identified and are used instead of serum in the culture medium

they include:

Epidermal growth factor (EGF)	Endothelial cell growth factor (ECGF)	Platelet derived growth factor (PDGF)
Staneley cohen                                discovered this GF.	This GF is isolating from eye and  brain.	This is an endogenous growth promoting protein.
Consist of 53  amino acid                      polypeptide chains.	It is also produced in the developing embryo.	Induce cell division in epidermal cells, leukocytes and T cells.
Sub maxillary gland produces this GF.	Molecular weight 16-17 KD.	Mainly involved in wound healing process.
This is known to stimulate the epidermal cell proliferation and nerve cell regeneration	A large number of mesoderm and endoderm derive cells including vascular endothelial cells, glial cells, smooth muscle cells and fibroblasts are induced by this factor in the culture condition.	2 types of PDGF  1- Platelet derived GFA (125 amino acid polypeptide chain) 2-Platelet derived GFB  (109 amino acid polypeptide chain)
EGF having major action on stem cell, leuckocytes, macrophages and tissue cells.
More number of animal cells shows response to the EGF in the medium.
This is also required for the embryo development.

      

                                                                                              

       Interleukin 1                Interleukin 2                 Nerve growth factor       Erytheropoietin

                (IL-1)                          (IL-2)                            (NGF)                          (EPO)

IL-1	IL-2	NGF	EPO
Known to produce by macrophages, monocytes, B cells, endothelial cells but mostly by macrophages.	It is 133 amino acid polypeptide chain.	Rita Devimontaleini discovered in 1950s. also known as Neurotrophins.	It is glycoprotein stimulate the division and differentiation of myloid stem cells to red blood cells.
In culture condition or invivo they have effect on varieties of cell types.	These are produced by T cells and generally help in proliferation and differentiation of all types of T cells.	It is 118 amino acid polypeptide chain.	Produced by kidney  and fetal liver cells.
They help in proliferation of stem cells, lymphocytes, fibroblast, B cells, TH cell and epithelial cell.	It also supports long term growth/maintenance of all cultures.	Molecular weight 20 KD.	Molecular weight 30,400 Dalton and 166 amino acid polypeptide chain.
IL-1 was known to induce protein synthesis, adhesion molecules production, extracellular matrix production and alters the permeability of cells.	Sometimes they also show activation and division of B cells.	Produced by sub-maxillary gland.	Protein contains two disulfide bonds and four sites of glycosylation.
Receptor for IL-1 is present on all the cells of the animal body hence they can act on the all cell types in culture system.		NGF regulates the development, differentiation and survival of neutrons in culture conditions.	It acts as mitogenic substance and enhances survival of cells in culture condition and prevents programmed cell death.
IL-1 is a stable polypeptide retaining its activity up to 56 degree Celsius and between pH 3-11.		It is not a good mitogen for the cells in culture.
It occurs in two molecular forms IL-1 alpha and IL-1 beta.