International Medical SchoolShah Alam Campus

Practical Record Book In

Microbiology

Prepared by

Dr. Saleh M.Y. Al-OthrubiPh D

Medical Microbiology and Medical Molecular Biology

Name: ………………………..………………………..………………………..…………………..

Matric No.: ………………………..………………………..………………………..…………..

Batch No.: ………………………………………………………………..………………………..

1

International Medical SchoolShah Alam Campus

Medical MicrobiologyLaboratory Manual & Practical Experiments Work Record

Name: ………………………..………………………..………………………..……………

Matric No.: ………………………..………………………..………………………..…

Batch No.: ………………………………………………………………..……………..

2

REGULATIONS AND SUGGESTIONS TO BE OBSERVED DURING THE DEMONSTRATION AND PARTICLES

4. Each student will be provided with a microscope and a set of stains, each will have in

addition to regular desk equipment, slides, cover-slips, etc, keep your work table clean and

tidy.

5. Students should come to the practical class in buttoned aprons and long hair of women

students should either be tied up or covered by aprons. Late comers are not allowed to enter

the class.

6. Students will sit in their serial order according to the number and shall work in small group

allotted to one teacher.

7. Talking and unnecessary movement of the student in the practical class from place to place

is forbidden.

8. Each student must bring his/her practical record book. Student must possess lead pencil,

eraser and coloured pencils (red, blue, violet, green, brown, yellow) and a piece of thin

clothe for cleaning and wiping the microscopic slides and cover slips etc. Avoid the use of

hand kerchiefs.

9. Each practical class will being with short discussion and instruction period. Do not begin

until you have received your instructions. Ask questions when you do not understand, the

method and purpose of any experiment. Good laboratory technique depends primarily on

what you are to do.

10. Before demanding your work, read over the exercise to be done and plan your work

carefully. Know how each exercise is to be done and what basic principles it is intended to

convey. Check up the microscope, clean the eyepiece and the objectives with cloth and see

that the condenser diaphragm and mirror are correctly adjusted.

11. Properly record all observations Sketches and diagrams should be neatly drawn in the same

colour as seen through the microscope, keeping the relative size of the bacteria and tissue

cells.

3

12. Each student should show his/her daily work including diagrams in the practical record

book and must get them signed by the teacher with the date before he/she can get his/her

attendance for the day's practical class.

13. Because many of the organisms with which you will be working are potentially pathogenic,

it is imperative to develop aseptic technique in handling them. Avoid any hand-to-mouth

operations.

14. Report immediately all accidents such as cuts, burns or spilled culture to your instructor.

Take all precautions to avoid such accidents. Discard slides and all dirty glass ware in the

container provided.

15. The students will be held responsible for the breakages and missing articles loaned to

him/her and will be charged for such things.

16. The student who does not follow the above rules will be sent out of the class.

17. After the completion of the day's work and before leaving wash your hands with carbolic

soap with water.

18. At the end of session the record book completed in their own hand writing should be

submitted for scrutinizing and certification by the Professor and Head of the Department

for having completed the course in Microbiology.

4

Name: ……………………………………………………………..…… Date: / /

Laboratory Experiment (1)

The Microscope and its use

5

1- Introduction

2- The support System of the Microscope (body, base and stage)

3- Illumination system (mirror, condenser and iris diaphragm)

4- Magnifying system (optical lenses, objective lenses…)

5- The adjusting system (coarse and fine adjustment knobs)

6

7

The compound microscope is essentially an optical instrument to magnify microorganisms for

purposes of study.

The microscope in essence, consist of the following :

1. The Support System in the form of the base, body and the stage.

2. The illuminating system consisting of the mirror and condenser with the iris diaphragm

3. The magnifying system consisting of the train of optical lenses - the objectives on the

rotating nose piece, the mechanical tube and the ocular or eye-piece.

The adjusting system consisting of coarse and fine adjustment knobs and the rack and pinion

system on the stage.

It is the enlargement of the object achieved by a microscope. Magnification through a

microscope is achieved by a series of two lens system. The lens system nearest the object

'objective' magnifies the specimen and produces a real image inside the mechanical tube. The

'Ocular' or 'eyepiece' lens system magnifies the real image further yielding 'virtual image' which

is seen by the eye.

Hence there is magnification at two levels. The final magnification achieved by a microscope is a

product of the magnifying power of the eyepiece and the magnifying power of the objective

(considering the mechanical tube length as constant).

The resolving power of a system of lenses is its ability to show two closely adjacent points as

distinct and separate. It is this power which determines the amount of structural detail that can be

observed under a microscope.

8

Resolving power of normal eye 0.2 mm

Resolving power of good light microscope 0.25 µm (micron)

Resolving power of electron microscope 5 Angstrom units.

Important steps in the use of a microscope:

There are usually three objectives lenses in a microscope. The low power (lOX) and high dry

power (40X) objectives are used for examination of wet cover-slip or hanging drop preparations.

The oil immersion (100X) objective is used for stained smears or sections only.

1. Before observing a smear, adjust the illuminating system for maximum light.

2. With the low power objective in position and viewing through the eyepiece turn the

mirror towards source of light.

3. Set the position of the mirror when the field of vision is brought to the maximum

without any glare.

4. Place the wet preparation on the stage between clips.

5. Observe from the side that the smear is just above central hole in the stage.

9

Diagram of the compound MICROSCOPE:

Write the names of its parts and its function:

1- ……………………………….

2- ……………………………….

3- ……………………………….

4- ………………………………..

5- ………………………………..

6- ………………………………..

7- ………………………………..

8- ………………………………..

9- ………………………………..

10- ………………………………..

11- ………………………………..

12- ………………………………..

10

This diagram for helping you and the names of the parts you can read it from the picture of the Microscope that given in the first page:

11

Body Tube

Nose Piece

ObjectiveLenses

Stage Clips

Diaphragm

Light Source

Ocular Lens

Arm

Stage

Coarse Adj

Base

Fine Adjustment

12

A. When unstained preparation is to be studied use low or high dry power objectives:

1- Reflect light using concave mirror.

2- Keep the condenser in the lowered position.

3- Partly close the iris diaphragm to cut down light.

4- After examination under the low power shift to high dry power by rotating the nose

piece.

5- Never attempt to bring the object into focus by lowering the body tube while looking

through the eye piece.

6- Always lower the objective (either low or high power) to near about the working

distance for the power (refer figure). Watching it from the side.

7- After ensuring that the objective is near about the working distance look through the

eye piece and try to focus.

8- Focusing is achieved by movement or coarse of fine adjustment slightly.

B. When stained smears are to be examined use oil immersion objectives:

1- Reflect light using plane mirror.

2- Keep the condenser fully raised.

3- Open the iris diaphragm fully to allow maximum light.

4- Place a drop of oil on the smear (ensure the stained smear is on the top of the slide).

5- Looking from the side (refer figure) over the oil immersion objective till it touches the oil

on the smear and is just above the slide. (It should not touch the slide)

6- Look through the ocular, bring the smear to sharp focus using the fine adjustment.

13

PECUTIONS:

1- Before and after use, clean the lenses with tissue paper or lint cloth.

2- After use keep the low power in focusing position and condenser lowered down.

3- Do not use the microscope in a titled position when examinin gunder oil immersion or

examining wet coverslip or hanging drop preparation.

EXERCISE:

1- Study the different parts of the microscope and get conversant with their proper use.

2- Study the given smear under all the three objectives and note down magnification and

resolution.

14

Diagram illustrating the optical tube of the Microscope

Diagram showing path of rays through

(1) Dry Lens (2) Oil immersion lens

15

Diagram illustrating the numerical aperture

Diagram illustrating spherical aberration

Diagram illustrating chromatic aberration

16

Path of rays through the dark ground condenser

Low power High power

Oil immersion

17