The experiment performed in the Lab was isolation of microbes taken from us and the environment. We used Nutrient Agar which is a growth medium used to culture microorganisms or small plants and Sabourand Dextrose Agar plates used to cultivate moulds and yeasts. The objective of it was to demonstrate that microbes are everywhere. We expected to find a variety of bacteria, moulds and yeasts. We were introduced to aseptic techniques as they help ensure that only certain microorganisms are present in the plate.
These methods also guarantee that microorganisms do not escape from the specific petri dish, contaminating the laboratory and possibly causing disease. Describe features of colonies. Materials required: Nutrient Agar plate (N. A. ) Sabaround Dextrose Agar plates (S. D. A. ) 4x sterile Swabs 1x Diluent (universal bottle) Method: Firstly, NA plate was exposed to microbes from me using sterile swabs. The swab was scrubbed inside my nails and then rubbed over ? of the plate. Secondly, for the environment- the swab was dipped in diluent to moisten and then applied to the drainage pipe from the laboratory.
This swab was rubbed over the second half of the plate. NA plates were incubated inverted at 37oC for 48 hours. We repeated the procedure with the SDA plate at 22oC for 5 days. All plates were labelled with our initials, part of the body/environment swabbed, incubation temperature and media used. Results obtained: Moulds are actually fungi, and they often appear whitish grey, with fuzzy edges. They usually turn into a different colour, from the centre outwards. Examples are shown below: On the right hand side we can see a circular green mould colony and round yeast colonies.
Left hand side of the plate shows round bacterial colonies. The dominant colour is cream. However, we can appreciate a round colony in a pinkish colour. We can see mould colonies in a yellowish colour at the top. However, the handle’s side appears to have a darker colour and a green patch. It is interesting the way the mould has divided so rapidly that we can barely differentiate the two halves of the plate. The mould from the air conditioner could have contaminated the handle section. We can also notice small pinkish colonies in the centre of the air conditioner’s sample.
The bottom of the plate has black, yellowish and light green patches. In the sample taken from my nails we could see an agglomeration of a larger number of bacterial colonies. Colonies appeared punctiform with a wavy form and cream in colour. Unfortunately we could not see any sign of growth in the sample taken from the drainage pipe. We aimed to see microbial growth of each sample with a variety of bacterial colonies with several shapes and colours. Perhaps microorganisms taken from the drainage pipe were in the lag phase of growth and needed a longer or different type of incubation.
As per sample taken from the cheek we can distinguish several bacterial colonies circular in shape. Each distinct circular colony should represent an individual bacterial cell or group that has divided repeatedly. Some fungi and moulds can cause a variety of skin diseases such as athlete’s foot, jock itch, and ringworm. They can also cause pulmonary and internal infections. However, others are beneficial such as Penicillium which produces the antibiotic penicillin and Saccharomyces is the yeast used to make bread rise and to brew beer.
Many bacteria are dangerous pathogens such as Salmonella (food poisoning), Bacillus anthracis (anthrax), MRSA responsible for many serious infections. Nevertheless not all bacteria cause diseases. Lactic Acid bacteria enhance health and protect us against pathogens and carcinogens. There are many different types of bacteria in our mouth and intestines that produce some vitamins and ferment fiber to produce short-chain fatty acids. Microorganisms are essential on Earth. On the other hand, we can appreciate the importance of hygiene in our daily lives to avoid harmful levels of pathogenic bacteria and fungi.