Observation of Microbes In The Living State

Microscopy Methods in Microbiology
Microroscopy Methods in Microbiology Part 2
Microroscopy Methods in Microbiology - Introduction
Observation of Microbes in the Living State
Observation of Microbes in Smears
Dyes and Staining
Useful pH Range and Colour Change of Some Indicator Dyes
Factors Affecting Staining
Microscopy and Micrometry
Microscopy and Micrometry - Introduction
Behaviour of Light
Light Theories
Resolving Power
Refraction and Reflection
Bright Field Microscopy
Use of Bright Field Microscope

Observation of Microbes In The Living State

	Observation of Microbes In The Living State In order to see microbes in living condition, one has to keep sample to be examined in liquid. This is because, bacteria and other microbes die rapidly in the absence of moisture. The techniques available for the observation of microbes in living state are generally called as microculture techniques (7). These methods are used in microbiology with the following objectives. To study the shape and size of individual organism, to observe characteristic arrangement of cells and spores, to check that the organism in question is motile or not? And to study the growth parameters, behavioral reactions etc.
Optical or light microscope is sufficient for making the observation of shape, size and other morphological features of a living microbe. By means of phase-contrast microscope it is possible to observe living microbe in the greater detail, but its use in bacteriology is limited and is not a routine. In order to get the most satisfactory results with light microscope for the above purpose, points necessary to remember are as follows. (i) it is advisable to use high power objective for the observation. Use of oil-immersion objective will present two problems. First, oil makes the cover glass to cling to the objective and due to this it will make movement along with the objective up and down during focusing. This will result into entry of bubbles in the preparation which will constantly interfere with the observation. In addition to this, it will also create current in the liquid and will cause artifical movement of the object in question.
Second, oil-immersion objective gives higher magnification and as a result some of the living objects, which are motile will leave the field before they are sufficiently observed. (ii) The observation should be carefully noted down as fast as possible since, the object will not remain in the focus for the longer time and the preparation has a tendency to dry rapidly. (iii) During the observation amount and intensity of light should be reduced. This is essential to distinguish microbial cells form the environment in which they are suspended, having the similar refractive index to themselves. This can be achieved by partially closing the iris diaphragm and lowering the condenser of the microscope
(iv) Avoid petroleum jelly to get over objective. If, this happens, a thorough cleaning of the objective must ensure anberra offers a special education programme in English language. The University provides the following programmes: st of English as a Foreign Language . (ToEFL), 550 with a Test of written English (TWE) of 4.5 or a score of6.5 in International English Language Testing System (lELTS).

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