what is History development and microscopic? Louis pasture a 5 contributions? Robert koch a 3 contributions?Edward jenner?

History development and microscopic
1860- 1910 a Golden age of microbiology
Louis pasture a 5 contributions
[a] Tartaric acid acrystals {microscopically}
[b]Fermentation by yeast and bacteria
[d]Air contain microbes
[E]Immunity-Anthrax
Robert koch a 3 contributions
[A]Germ theory of disease
[B]specific organism aspecific disease
[C]pure culture techniques
Edward jenner
[A] vaccinea smallpox
-The period between 1860- 1910 is called the” Golden age of microbiology”
Louis pasteur :-
By 1860 some scientist had begun to realize that there is a casual relationship between the development of microorganisms in organic infusions and the chemical changes that take place in these infusions. microbes are the agents that bring about the chemical changes
His main contribution to the development of MB  are as follows:-
1.       Tartaric acid Inorganic compounds formed of two types of crystals that could be  separate microscopically
2.       Chemical changes, as fermentation {or}  vital processes brought about by the activity of microbes as yeast and bacteria and that they could be a cause of diseases
3.       First demonstrated that air does contain microorganisms
4.       Discovery of anaerobic life, and introduction of the terms aerobic and anaerobic
5.       Discovery of immunity in sheep against anthrax
Robert Koch:-
1)      The German doctor. He is credited for his following main contributions to development of microbiology
2)      Final proofs that bacteria could be isolated and shown to cause diseases, while working on anthrax disease of animals thus he presented his “germ  theory of diseases”
3)      Developing the series of  procedure –Koch’s by which a specific organism could be related to a specific disease
4)      Development of pure culture techniques
Edward jenner :-
1)      He developed the vaccine that resistant to smallpox injection
2)      He also developed a vaccine of cowpox
Compound microscope:-
1)      The dual lens system is referred to as a compound microscope
2)      A laboratory microscope usually has three objective lens called the low power high  power and  oil immresion  lenses. Generally these magnify an object 10,40,100 diameter, magnification can be represented by “x”
Resolving power:-

1)      This is ability to transmit light without variation
2)      If two objects are close to each other, these must be distinguished clearly as distinct, sharp objects.
3)      The resolving power of lens system is the number used to determine the size of smallest object that can be seen clearly.
4)      It varies for each object.
6)      Numerical apparatus relates to the  come of light, that will inter objective.
7)      For low power objective N.A is 0.25
8)      For light power objective N.A is 0.65
9)      For oil immersion N.A is 0.25

10)   R.P for low power

11)   In low power objective certain bacteria can’t be seen clearly, be seen clearly, but larger objects .such as protozoa, may be easily discerned for the oil immersion
12)   Walking distance is between the slide and button of the lens
13)   For low high power and oil immersion of the objectives 6,8,0.73 and 0.12 nm respectively
Dark field microscopy:-
1)      In the in this dark background is established and only the object is illuminated.
2)      A Special condenser scatters and cause  the light to hit the object  from different directions.
3)      Some light is reflected from object into the lens  and the object is seen clearly but since there is no direct background light. surrounding area appears dark.
Applications:-
1)      To  diagnosis of certain small living organisms near to the limit of resolution of the microscope must be observed.
2)      Example :- syphilis spirochete, treponema  pallidum may be seen in scrapping taken  from  a skin lesion
Phase contrast microscopy:-
This allows organisms to be seen alive and without staining one can easily see the internal details which cannot be easily visualised.With bright field microscopy bacterial granules, fine structure of protozoa and fungi may be studied
The PCM contains a series of special filters and diaphragm that split the light beam and throw the ray slightly but  of phase around microscopic object as well as through them, and the small difference  in the densities of the  object show up as different degree of brightness and contrast.
Fluorescent microscopy:-
1)      The process consists of containing a microbe with a fluorescent dye such as fluorescence, Rhodamine {or}rodospine and eliminating it with ultra violet light.
2)      As electrons in the dye are excited the move to high energy levels . then quickly drop back giving of the excess energy as visual light.
3)      The objective appears fluorescence.
4)      The most important application of this microscopy is in the florescent  antibody technique.
Electron microscopy :-
In this an unusual short wavelengths  of the electrons beams, sub for the light energy.
The wavelength of about 0.005 nm increases the resolving power of the instrument two fractions of a nanometre . It makes it possible to see viruses and large molecules clearly.
Tem:-
1.       This is used to see fine structures of the cells. ultra thin sections of the object are prepared by embedding{or} freezing the specimen  and  sectioning it with a diamond {or} glass knife.
2.       They are stained with a heavy metal gold {or} palladium to make certain parts dense, and inserted in the vacuum chamber of the microscope .
3.       A 10,00,000 electron beam is focused on the section and manipulated by magnetic lens.
4.       A photographs prepared from the image may be enlarged with enough of resolution achieve a total magnification of over 20 millions times.
5.       Object as small as 1.0 nanometres may be observed.
SEM :-
1.       This microscopy allows surfaces of objects to be seen in their natural state without staining
2.       The specimen is putting into the vacuum chamber and coloured with thin cold to electrical conductivity and thus forms  a less blurred image.
3.       The electron beam then sweeps across the object building an image as line by line as in a T.V, camera.
4.       An electron straight the object may knock showers of a electron and capture  dictators to form a image.
5.       Magnification with a microscope are limited.

 

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