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University Degree: Microbiology
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No other life forms are as important as microorganisms for the support and maintenance of life on Earth�. Perhaps the most commonly used bacterium in the laboratory is Escherichia coli due to its incredibly fast generation time of 20 minutes when grown in a pure culture under optimal conditions�. The main bacteria utilized in this practical was Bacillus subtilis, a Gram positive bacterium, measuring about 1�m in diameter. This bacterium is in the genus Bacillus which are rod-shaped bacteria and are either aerobic or facultatively aerobic� but under certain conditions, can also be anaerobic. They are widely found in soil and water and are able to form endospores under adverse environmental conditions.
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Indole is a compound derived from the amino acid tryptophan. A broth of tryptone is inoculated with two loopfuls of each bacterium. If the bacterium is one which converts tryptophan to indole, a red surface layer appears upon addition of dimethyl-aminobenzaldehyde, more commonly known as Kovac's reagent. Otherwise, the colour of the broth will remain completely yellow (Madigan et al, 2009). In the urease test, a urea broth, yellow before incubation, is inoculated with two loopfuls of each bacterium. If the broth, after inoculation, increases in acidity, the colour changes to pink with the presence of a phenol red indicator.
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After which the filter is incubated in a solution that contains the labelled probe in the hybridisation step3. It is usually carried out overnight but in some cases between 1-48 hours3. After hybridisation, the filter is washed to remove the probe and the stringent of the washing can be altered so that only probe molecules that are completely base-paired with the immobilised target are left on the filter or that the probe molecules that have hybridised to related sequences forming duplexes that contain mismatches are also left on the filter3. Such washing of filter may take about 30-60 minutes3.
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Managing Fusarium wilt disease is a achieved through chemical soil fumigation and resistant cultivars. Now there are available broad spectrums of biocides used to fumigate soil before planting as Captan, Benomiel and other commercial varieties ( Fravel et al., 2003) But they are have a negative impact on the environment . The environmentally save method is the use of BCAs. But[W2] resistance breeding are very difficult when no dominant gene is known (Fravel et al., 2003). Further more the pathogen can overcome the plant resistance. Virulent races of F.oxysporum f.sp. ciceris have undermined the importance of resistant cultivars of chickenpea ( Haware and Nene 1982).
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The veins collect the blood from the capillaries, and the branches of the veins join to larger veins which deliver the blood back to the heart. The blood from the veins fill the heart as it relaxes during the interval between each contraction. The right side of the heart receives blood from the body and pumps it through the pulmonary artery to the lungs. There it picks up fresh oxygen and releases carbon dioxide. The left side of the heart receives oxygen-rich blood from the lungs, and pumps it through the aorta to the body (British Heart Foundation 2006).
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They form the basis of the food chains, break down waste and recycle chemical elements such as nitrogen and phosphorus. Microbes such as unicellular algae have a role in photosynthesis, and many microbes live in the digestive of humans/ animals to aid digestion and synthesise certain vitamins. 'Biotechnology is the application of biological systems, organisms or processes in manufacturing or service industries...it is a composite science, involving microbiology, genetics, biochemistry and engineering', (Lowrie and Wells, 1994:38). Figure 1.2 shows the diversity of biotechnology Figure 1.2: Diversity of Biotechnology (Source: Madigan, et al, 2003: 6)
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This water bath is used in several activities. 2. 1 ml of apple juice and 3 ml of Benedict's solution are placed in a test tube, and a control is prepared. 3. The two tubes are placed in boiling water for 2-3 minutes. 4. The color of the solution is observed and note whether a precipitate has formed. 5. The test is repeated with coke, potatoes, onions and soy beans. Results are recorded. B) Starch Materials: * * Apple juice, coke, potatoes, onions, and soy beans * Test tubes * Iodine reagent Methods: 1.
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Once in the cytoplasm of the host cell the bacteria replicates and concomitantly becomes covered in host actin filaments. When the actin polymerises at the base of the actin 'tail' the bacteria is propelled to the edge of the host cell. Once at the cells' edge the bacteria protrude from the surface forming pseudopods. These are in turn recognised by neighbouring cells and the bacterium is internalised. The bacterium this time is internalised into a double membraned vacuole. These membranes are lysed by another pore-forming protein, phospholipase C (PLC), and the cycle begins again (adapted from Cossart and Lecuit, 1998).
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Variables In this experiment, the variable that is measured- the "dependent variable" is the volume of oxygen evolved which is an indication of the activity of catalase in the reaction. The variables which have an effect on the amount of oxygen evolved- the "independent variables" are: * Volume of hydrogen peroxide * Presence of copper sulphate * Time Other factors which are not necessary for the experiment- confounding variables but will have an effect on the dependent variable (volume of oxygen evolved)
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Qualification and quantification of microorganisms in soil role of microorganisms in the nitrogen cycle.
There may be hundreds of millions to billions of microbes in a single gram (Table 1). The most numerous microbes in soil are the bacteria followed in decreasing numerical order by the actinomycetes, the fungi, adapted for exploiting the three-dimensional pore network of the soil, soil algae and cyanobacteria (photosynthetic microbes which can add small amounts of carbon to soil) and soil protozoa (unicellular soil organisms that decompose organic materials as well as consume large numbers of bacteria) (Sylvia et al., 1998). Microbial Group No./Gram of soil Bacteria 100,000,000 - 1,000,000,000 Fungi 100,000 - 1,000,000 Algae and Cyanobacteria 1000 - 1,000,000 Protozoa 1000 - 100,000 Table 1: Numbers of Microbes in Soil Source: Sylvia, Fuhrmann, Hartel and Zuberer, 1998.
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This method shows that enzymes with their precise structure fit perfectly into their substrate to break it down. If their structure changes just slightly then they will be unable to fit precisely into their substrate's shape and they will be useless. Background Information and secondary sources used: Biological Studies by Henry Wilkinson, published by Nelson, page number 46. Encarta '97 Prediction In the experiment I shall be testing six different temperatures: 20?, 30?C, 40?C, 50?C, 60?C and 70?C. This leaves a range of 50?C and I feel that this is a wide enough variety to obtain a valid conclusion.
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