Thursday, 2 January 2020

Microbiology laboratory most commonly used glassware


Equipment Safety
Handling of equipments was one of important aspect when working in the laboratory. Careful handling and proper working procedure must be followed while handling any equipment in the laboratory. Students should aware about the safety instruction for all instruments and equipment used in the laboratory. Following sections described some of the procedures and precaution of laboratory instruments which were commonly used in the Microbiology laboratory.
Common Glassware
In Microbiology laboratory most commonly used glassware was as follows.
·   Test tubes
·   Culture tubes
·   Petri dishes
·   Measuring cylinder
·   Pipettes
·   Glass spreader
·   Flasks
·   Screw-capped glass bottles
·   Haemocytometer etc.
1) Test Tubes, Culture Tubes and Screw-Capped Tubes
The test tubes are made up of glass, in which one end is closed and other end is open. The closed end of tubes wall is curved slightly, it is known as test tube, and therefore in culture tube side wall is smooth. While open end of test tube was fitted with plastic cap, it is called as screw-capped tubes. In general test tubes were used to collect the water samples for the experiments and used for testing the chemicals etc., culture tubes are used to prepare the agar slant to cultivate the microorganisms. The screw capped tubes were used to preserve the microbial cultures. Nowadays most of the microbiological laboratories use caps in different materials like stainless steel or heat resistant plastics and it was very easy to handle.
2) Petri dish
A student (R. J. Petri) of most renowned bacteriologist Robert Koch devised this dish, so it is called as “Petri dish’. It made of two different glass dishes which was bottom surface portion (lower half) and upper half portion (lid) that serves as a loose cover’s the bottom. The diameter of the dishes were vary depends on the requirements. For routine purposes, approximately 15 cm in diameter dishes are used. The Petri dishes can be easily sterilized by using the autoclave and hot air oven. The Petri dish was one of the most important glass ware in various microbiology laboratories for the isolation and cultivation of different types of microorganisms. This provides the enough space to grow the microorganisms.
3)  Pipette
Pipette was a cylindrical and graduated glass apparatus, used to transfer the aseptic measurable liquids in laboratory. It has a one taper end and other end was normal called as mouth piece. The middle portion of the pipette was wider as like mouth end. The volume of the pipette was graduated with numbers from taper end to mouth end. The measuring capacities of pipettes was vary from 0.1, 0.5, 1, 5, 10 ml etc. which depends on the requirements. Pipettes should be sterilized by keeping them first in a steel can or wrapped individually in brown paper and sterilized at 121°C for 30 minutes in autoclave.
4) Glass Spreader
L-shaped glass rod was called as Glass spreader. It is made by blending the normal glass rod to get the L- shaped structure. The main purpose of the glass spreader is spread the microorganisms present in liquid medium on to the agar medium evenly. It has one long arm and small arm, long arm is used for handling and small arm was helpful for spread the liquid medium over the agar surface.
5) Haemocytometer
The Haemocytometer is a device used to measure the blood cells, fungal spores and bacterial cells etc. It consists of a number of chambers. Each big chamber has 1 X 1 X 0.1 mm = 0.1mm3 volume with an area of 1 X 1mm = 1mm2. The depth of chamber is 0.1mm. (1 X 1 X 0.1 mm = 0.1mm3 = 0.0001cm3 = 10-4cm3 = 10-4 ml) Hence, the bacterial cell count in the large chamber will be multiplied by 104 to give an estimate of bacterial cell number/ml. Each large chamber has 9 medium-sized chambers with 0.2 mm length, 0.2 mm width and 0.1mm depth with a volume of 0.004 mm3. Each medium sized chamber is divided into 25 small chambers with 0.04 mm length, 0.04 mm width and 0.1mm depth with a volume of 0.00016 mm3.


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