Most differential stains have a challenge step that follows staining with a primary dye. In the Gram stain the challenge step is a rinse with either ethanol or acetone (either may be used). This step dehydrates and tightens the cell wall of Gram positives (mainly peptidoglycan) such that the rinse does not enter the cell. Gram negatives have mainly a lipid cell wall (even though they do contain peptidoglycan) that allows the challenge rinse to penetrate the cell and rinse out the crystal violet-iodine complex rendering the Gram negative cell colourless. Thus, the Gram negative cells must be stained to be seen, and this is done with the counter stain.
This kind of Staphylococcus aureus is called “MRSA”, referred to methicillin-resistant S. aureus. This bacteria are multi-resistant to beta-lactam antibiotics, meaning that they are resistant to different kinds of antibiotics, such as penicillin, methicillin, dicloxacillin and cephalosporin. As the process goes, that normal Staphylococcus aureus are being killed by penicillin antibiotic, and the ones that are resistant survived and keep on reproducing, Staphylococcus aureus bacteria that is penicillin resistant spread in the community and its amount kept on increasing. This made natural selection to occur, which the bacteria that are antibiotic resistance are suitable ones and they survived in
Methyl Red turns red for a PH that is lower than 4.4 and it turns orange for a Ph between 4.4 and 6.0. Methyl Red will turn yellow with a Ph of 6.0 or above. Red means that the bacteria produces stable acid end products, yellow color means no acid end products, and orange is inconclusive. ("Lab manual," nd, p. 140) the Voges-Proskauer test determines the
Escherichia Coli is a large, diverse group of bacteria of the Enterobacteriaceae family. A German physician named Dr. Theodore Escherich discovered it in 1885. The genus is composed of gram-negative, aerobic, facultatively anaerobic, non-spore forming rods. The organism’s usual habitat is the digestive tracts of humans and animals. Escherichia Coli is a beneficial function in the human body because it synthesizes useful vitamins such as Vitamin K. E. coli also acts as competition in the intestine by suppressing the growth of pathogenic bacteria that may be present or ingested.
Title: Water Potential and Osmosis Aim: To determine the solute potential of plant cells Discussion: The aim of this lab was to determine and observe how six different solutions of varying sucrose concentration affected the epidermis of an onion in terms of the solute potential. Onions are made up of 89% water and 8% to 9% soluble sugars, the rest is minerals, fats, proteins, and sulphur compounds. The solute potential (ψs) is the reduction in the water potential of the solution in the cell due the presence of particles dissolved in the solution. The presence of solutes in water causes the solute potential to decrease and it reduces the free energy of water. This is so because water molecules will tend to bind to the solutes rather than moving freely and away from the solution.
The role of microbes in human health and disease Key terms: Specific | It’s only matched by one other thing | Neutrophils | They are quick and respond to inflammation. They engulf and digest bacterial pathogens | Macrophages | They engulf and digest ‘debris’ | Complement proteins | They make pathogen membranes porous | Lymphocytes | Receptor binding sites | Susceptibility | Lack of resistance or vulnerability to disease | Resistance | The ability to ward off disease through the various defence mechanisms | Eosinophils | A white blood cell containing granules that are readily stained by eosin | Phagocytes | A type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles | Basophil | A basophilic white blood cell | Normal flora is the bacteria which are found on our body on a semi- permanent basis without causing disease. Normal flora is especially important in the large intestine. They are also found in the nose, mouth, on skin and down the throat. The roles of normal flora are to produce compounds which kill other bacteria.
| Practical Report | | | | Practical Report Introduction This specific experiment will demonstrate both the efficiency and the disinfecting capabilities of the various disinfectants used and if the experiment is followed correctly the results deemed should be noted that if the substance possess a chemical substances that inhibits the growth of the bacterial culture placed onto the agar (E.Coli) that inhibition zones will be created and we can tabulate and record the observation thus walking away with an understanding of the efficiency of the tested disinfectants used and their success rate. What is known about E.Coli is that it is normally found in food it is a Gram negative, rod shaped bacterium that can help the body break down and assists the body in digestion of food (Dowshen, 2009).Although certain strains of the E.Coli are pathogenic to humans such as the serotype O157:H7, this specific strain of E.Coli is known to cause food poising and can escalate and become life threatening (Nordqvist, 2011). Domestos is chlorine based bleaching agent (Directa, 2009) and is a common household cleaning substance that is used. Handy Andy is a common and popular general house hold cleaner. Dettol is trusted antiseptic and disinfectant and is widely used to fight unwanted bacteria (Thompson D. M.) It has a distinct and characteristic phenolic odour.
The reaction begins with the oxidation of the polysaccharide rich fungal cell wall, by use of Chromic Acid. Oxidation of the polysaccharides forms and releases aldehyde groups, which now cover the cell wall. When Methanamine Silver solution is added, the aldehyde groups work together to reduce the silver ions to metallic silver. Gold Chloride is then added as a contrast to the silver, to produce contrast and clarity, making the fungi more crisp and easily viewed. Specimen: The specimen is to be fixed in 10% Neutral Buffered Formalin, and paraffin sections should be cut at four to five microns and placed on Plus (+) slides.
These include anaerobic conditions (such as rotting carcasses or canned food), warmth, and mild alkalinity. The photo shows the bacillus shape of the bacterium C. botulinum. After germination, clostridial spores release neurotoxins. There are 7 antigenic types of neurotoxins, classified as A through G. Typically, different neurotoxin types affect different species. Only a few nanograms of these toxins can cause severe illness.
According to the results of the experiment, beetroot has a dense chloroplast, with the plasma membrane protecting the inner part of the cell from the chemical substances. The experiment was used to analyse the effectiveness of each solution with various pH levels on the beetroot slices, and how the pigment diffuses from the beetroot slices into to the liquid. Hypothesis: That due to the high Ph level in the methylated spirits, the majority of the red pigment in the beetroot will be extracted. Variables Control of variables Controlled Variables | How to control | Number of sliced beetroot | Count (5 each time) | Volume of solution | Volume can be measured each time | Time of beetroot in solution | Time can also be measured consistently | Size of the container | Use the same type of container for all solutions | Size of beetroot slices | Use the same stencil to cut beetroot or measure the size of beetroot every time | Materials - 6 x plastic petrie dishes = 1cm x 8.5cm - 35 x 1cm beetroot slices - Ruler - Wax black pencil - 1 x test tube - Test tube rack 1 x pipette - Plastic tongs - Plastic gloves - Safety glasses - Bunsen burner Solutions: - Boiled distilled water - Accreted water - NACI - Methylated sprits - 1% detergent solution - Distilled water - HCI Method 1. Label each 6 petri dishes with the