LAB 1 : Principles and Use of Microscope ( Part I )

A. Setting up and using the microscope

      　Introduction:

      　In order to be seen, microorganisms need to be magnified. Despite advances in other area of microscopy (for example, the electron microscope), the light microscope is still the instrument most frequently used for viewing microorganisms.

            Objective:

            Learn to use a simple bright-field microscope correctly.

            Materials:

            Microscope slide, cover-slip, specimen slide

           Procedures :

1.  The microscope is placed at a comfortable position to make sure the observation is more easy.
2. The main switch of the microscope is then turn on.
3. The light intensity is then adjusted using the brightness control.
4. The revolving nosepiece is rotated to bring the 4X objective lens into the light path.
5. A line is marked on a clean slide with a marker pen. The slide is then placed on the stage of the microscope and secure by spring clip. The slide is moved to the light path using the coaxial stage control knobs.
6. Both of the eyepieces is adjusted until a single circle light is been seen.
7. The tube length adjustment ( diopter) ring on the right eyepiece is adjusted to match interpupillary distance .
8. The marker-pen mark is focused by adjusting the coarse and fine adjustment knobs and observed through right eye.
9. The left eyepiece is then focused using the tube lens adjustment          (diopter) ring and observed through left eye.

        

        Using microscope objective viewing:

1. Marker pen slide is replaced with specimen slide.
2. By watching at the side of microscope, nosepiece was rotated to 10x objective lens.
3. The specimen is focused using fine adjustment knob and by moving the stage.
4. Condenser and light intensity were adjusted to obtain better image.
5. The image of the specimen was capture.
6. Step 2 to step 5 is repeated by using 40x and 100x objective lens.

      Results:

      

      The slide

     Observation :

     Penicilium sp under 4x magnification

    Penicilium sp under 10x magnification

    Penicilium sp under 40x magnification

        Discussion :

      By using the magnification of 4x, 10x, and 40x we are able to see a very clear image of the penicillium sp. The specimen is observed from the lowest 4x magnification to the highest magnification which is 40x. We can see clearly the morphology of penicillium sp. The penicillium sp was no need to observe under the oil immersion(100x) objective lens because it is type of fungi.

Scientific classification of penicillium sp. :

·         Kingdom : fungi

·         Class : eurotiomycetes

·         Order : trichocomaceae

·         Genus : Penicillium 

     

     Morphology

     o  Colour:  Red

     o  Shape:  brush-like structure        

     o  Surface: rough

       References :

           ~http://en.wikipedia.org/wiki/Penicillium#Characteristics

         ~http://www.caltexmoldservices.com/section/mold_library/penicillium/