Microbiology lab session 1 observing bacteria

medical microbiology laboratory manual pdf

The spheres now appear to include dark and light color The spheres seem to have a nucleus manufactured from several more compact spheres. The iodine from each slide with tap water and lightly blot were washed with bibulous paper to remove excess water after 1 minute, but the slide was not dried completely.

Advanced microbiology lab techniques

Gram positive cells are sensitive to the action of certain antibacterial agents like penicillin due to lack of outer membrane which acts as barrier to certain antibacterial agents, while gram negative cells are more susceptible to mechanical breakage as the amount of peptidoglycan is small. Could other dyes be substituted for crystal violet in gram stain procedure? As usual, before we started the experiment, it is crucial for us to perform aseptic technique In order to minimize contamination. Before that, the slides were given the oil in order to refract light rays towards the center of the lenses. The addition of alcohol is not be more than 15 seconds as this would break the cell wall of the bacteria, thus resulting in no stain to be observed. In Mim's Medical Microbiology 4th ed. This is because the antibacterial agents have different types of action such as injury to the plasma membrane, inhibition of cell wall synthesis and protein synthesis, does not only depend on the gram reaction. Next, we washed the iodine with tap water and dried off the excess water. The cells is very much fuzzy and not well described Appears to look like the sun with all the inner cellular having multiple textures. Knowledge of how distinguish the gram-positive and gram-negative bacteria properly. Iodine was being added as a mordent to form crystal violet-iodine complex, CVI complex. Ascaris Ovum Dozens of ova appear most look yellow some appear clear. In Prescott's Principles of Microbiology pp. A Gram-positive? Crystal violet dye can be replaced with Methylene blue.

Anabaena A paisley shaped cellular with bubbles in the membrane with a hollowed out center cell Several circular shapes with pink, yellow and hollow centers A great oval formed cell with yellow and red linings. What correlation is there between cell wall composition and Gram reaction?

Microbiology lab manual

Thus, the dye-iodine complex is retained during this short decolorization step and the bacteria remains purple. The smears was air dried and heated. This method is used to distinguish between gram positive and gram-negative bacteria which have consistent differences in their cell walls. I can view the outer ring of the cellular along with tiny sectors inside the cellular. The slide was briefly washed with tap water and the excess was drained off. This particular lens have more mirrors inside and it requires the use of oil to refract light rays towards the center of the lenses. Anabaena A paisley shaped cellular with bubbles in the membrane with a hollowed out center cell Several circular shapes with pink, yellow and hollow centers A great oval formed cell with yellow and red linings. Yeast Is apparently several small spheres. This cause the gram positive bacteria appeared to be purple color as the CVI complex are being retained. As usual, before we started the experiment, it is crucial for us to perform aseptic technique In order to minimize contamination. Willey, J. I can see the division clearly and there appear to be tiny circles inside. Gram-staining was firstly introduced by Cristian Gram in However, the gram reaction does not ensure that the same antibacterial agent is able to destroy the 2 different species or strain of bacteria even though they showed the same result in the gram reaction.

However, before doing the experiment, we absolutely need to pay attention on the precautions. Finally, we observed our specimen using microscope under oil-immersion objective lenses.

How to culture bacteria in the laboratory

Before that, the slides were given the oil in order to refract light rays towards the center of the lenses. This complex enables the dyes to not be easily being removed. Knowledge of how distinguish the gram-positive and gram-negative bacteria properly. It interacts with the lipid membrane of both positive and negative bacteria, and this would cause the gram-negative bacteria to lost their outer membrane and exposing the peptidoglycan. This method is used to distinguish between gram positive and gram-negative bacteria which have consistent differences in their cell walls. In the next step, safranin was used to counterstain both smears. Paramecium Seem to be divided with nucleus centers. Before that, we absolutely must know about the proper procedures during this experiment such as prepare smears from culture of microorganisms, heat the smears, place the slide on a staining rack and so on. Therefore, CV-I and the outer membrane is washed away. This cause the gram positive bacteria appeared to be purple color as the CVI complex are being retained. Meanwhile, for safranin, it can be replaced with basic fuchsin. Appears to be clumps of lilac and violet tiny spheres.

A Gram-positive? Meanwhile, for gram-positive bacteria, the addition of alcohol dehydrated the layer of peptidoglycan which in turn would trap the CVI complex. The slide was briefly washed with tap water and the excess was drained off. The CVI complex are being washed from the outer membrane of gram-negative bacteria and cause the purple color to decolorize.

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