Algae, Fungi, and Bacteria - Growing Conditions, Benefits or Harm to Humans and Animals - Assignment Example

ALGAE SECTION Algae are diverse photosynthetic organisms that have simple cellular forms because they lack complex vascular networks and reproductive organs observed in higher plants. Algae can be aquatic or sub aerial and aquatic algae can be found in a broad pH range, differing oxygen and carbon dioxide concentrations, temperature and turbidity, they can also be planktonic or benthic (epilithic, epizoic epiphytic or epipelic). algae use photoautrophy heterotrophy to gain their nutritional needs. Most algae groups are considered photoautotroph’s meaning that they depend on photosynthesis to synthesise food with the use of sunlight as their energy source, and carbon dioxide as their carbon source for the production of carbohydrates. those that cant synthesize complex molecules like vitamin b12 or fatty acids are autotrophic. Cyanophyceae are a class of algae that are found in both fresh and salty water. They are photosynthetic and contain chlorophyll and phycobillins. During winter, there is less sunlight in comparison to summer. There is also increased could cover and low temperatures. Could cover affects the time light takes to strike the water surface and in turn this influences the rate of photosynthesis. As a result algae densities are low during winter because of the decreased rates of photosynthesis. The temperatures during winter are also very low and this decreases the rate of respiration/ metabolism in the organisms. There is decreased reproduction. The intensity of sunlight directly influences the rate of photosynthesis in algae. More sunlight results in more photosynthesis and hence increase in cyanophyceae densities within their habitat. During summer temperatures are high and the heat gives a suitable temperature for the organisms to thrive in. Enzymes operate best at optimum temperature and this increases the organisms rate of function. Increased respiration etc. Temperature affects the density of water higher temperatures mean less density and less resistance for aquatic animals. This increases the ease of algae predators to capture them and eat. The different climate seasons in an ecosystem influence the growth, reproduction and overall density of Cyanophyceae algae. Algae have been seen to occur in higher densities in the summer than in the winter. Mineralization is the process through which organic materials are transformed to inorganic materials. It occurs throughout the water column and this usually occurs during a season in the euphotic zone of the water body. The main effect of recycling minerals is the rate of recycling growth-limiting factors like sulphur, nitrogen, iron and phosphate. In aquatic bodies oxidative degradation of takes place in areas that have high oxygen concentration. It is important for the required concentration of limiting nutrients to be at a threshold concentration for the ominous survival of algae. With the changes in seasons the concentrations of these nutrients, for example nitrogen phosphorous and silicon, also fluctuate. This directly affects the growth and survival of algae in the aquatic environment. This fluctuation results in seasonal blooming of algae which is seen when conditions are optimum. Cyanophyceae algae require silicon for the construction of diatom during development. In cases of limiting silicon concentrations cell division is stopped in the G2 phase and cell cycle division is stopped. Silicon limitation is more prevalent in spring than summer and as a consequence the density of algal bloom is less in spring in comparison to summer. Nitrogen is generally the limiting factor for overall productivity in marine environments, and is more prevalent during winter. Nitrogen limitation leads to an immediate inhibition of protein synthesis in algae. Nitrogen limitation influences amino acid supply which in turn limits the translation of mRNA and reduces the speed of protein synthesis. This in turn results in reduced respiration and photosynthetic rates (due to lower levels of enzymes). Nitrogen is required in large quantities because it is a component of genetic material, enzymes and other important cell features. The nitrogen cycle greatly influences the availability of nitrogen for growth of algae. The nitrogen cycle generally involves, nitrogen fixation, assimilation, mineralization, nitrification, and denitrification. Cyanophyceae algae play an active role exclusively in nitrogen fixation and assimilation. Prokaryotic algae convert atmospheric molecular nitrogen into compounds like ammonia, and integrate the nitrogen with cellular components this process is referred to as nitrogen fixation. Eukaryotic algae use fixed nitrogen in its various forms, for example ammonia or nitrate, this process termed assimilation. The rates of Nitrogen fixation and assimilation are influenced by temperature. This is because the algae’s’ cellular activity is also influenced by temperature. Increased nitrogen fixation can be observed during warm weather conditions and this explains the spring and summer algal blooms. Phosphorous is an essential element for in growth algae. Decomposition processes increase the concentration of phosphorous in the body. Phosphorous is essential in genetic material, and is a crucial make up in various cellular content. Phosphorous in its form orthophosphate is the main limiting nutrient in aquatic bodies. Excess phosphorous will spark eutrophic conditions. Eutrophication leads to an increase in the primary production of the ecosystem. Algae bloom is harmful to several animals and plants. It increases competition for nutrients with other photosynthetic organisms and produces toxins that kill or harm other organisms for example cod larvae. The increased over production of limiting nutrients eventually leads to overproduction of algal blossom. This is as a result of the combination of factors that favour increased photosynthesis. Changes in the availability of nutrients cause shifts in algal communities. Phostoacclimation is a process through which algae are able to utilize sunlight more efficiently. It involves changes in cellular components especially photosynthetic organelles which increase the overall rate of photosynthesis. Phostoacclimation is adopted by plants in weather conditions that have high light intensity like during summer. The oxygen concentration in the algal aquatic system is essential for life. In winter, little oxygen is contributed from photosynthesis by algae and other aquatic plants. This is due to the a decrease in algae populations as a result of the cold (kills them). Their respiration and metabolic rates are also directly influenced by temperature hence a decrease in these is also observed. During winter the water oxygen concentrations are much higher than the oxygen water concentration of summer. There is decreased oxidative decomposition and the strong winter wind keeps water circulation. During the summer oxygen production is at its highest as a result of increased photosynthetic processes but there is also increase oxidative decomposition and respiration by other aquatic organisms. Long hours of daylight and increased temperatures maximize algae respiration and cellular activities. In addition decomposition rates are also highest in the summer due to temperature levels etc. Excessive vegetation as a result of algal bloom often interfers with the growth of other organisms. Algae are a source of food to many fish species which controll their population. FUNGI SECTION The kingdom Fungi consists of a diverse group of eukaryotic organisms. They are abundant in various ecosystems where they play a wide variety of roles. They have been found in a wide range of habitats including extreme conditions like deserts and deep sea sediments. They can be either parasitic, symbiotic or exist independently. Fungi produce a large range of metabolic products that have antimicrobial anti-cancer, cholesterol lowering properties. These metabolites also consist of antibiotics, vitamins like thiamine, nicotinic acid, riboflavin, amino-benzoic acid and other pharmacologically active compounds. A good example is Penicillin’s produced by fungi of the genus Penicillium. Penicillin’s have been used in the treatment of a wide range of bacterial diseases. For example penicillin G produced by Penicillium chtysogenum is used in the treatment of a wide range of bacterial infections. Fungi like Penicillium griseofulvum produce griseofulvin which is used to treat fungal infections. Tetracycline is a product of Streptomyces species of the genus Actinobacteria. It acts through the inhibition of protein synthesis in a wide range of bacteria. Tetracycline is used to treat acne, cholera among other bacterial infections. Erythromycin is produced by the Actinomycete Saccharopolyspora erythaea. It is a macrolide antibiotic used in place of penicillin for patients with allergic reactions to penicillin. The metabolic products of these fungi can be synthetically enhanced to produce alternative products that contain pharmaceutical activity. Other antibiotics produced by fungi include cyclosporine, erythromycin, tetracycline, and ampicillin. They are effective against a broad range of bacteria and are used to treat diseases like tuberculosis, syphilis and leprosy.. Mushrooms like Ganoderma lucidum and Cordyceps sinensis have antiviral activity and are greatly used in traditional Chinese medicine. Fungi are also used in mass production of proteins and vitamins that are used as supplements in human health. Fungi have long been a source of food for human beings with mushrooms being a good example. Edible mushrooms like Agaricus bisporus are used in salads, soups and a variety of dishes. The production of certain types of cheese, like blue cheese e.g. Stilton, require food processing that involves fungal species which impart a unique taste and flavour to them. Camembert and Roquefort types of mouldy cheese that are processed using Penicillium species like P. Camemberti and P. Roqueforti respectively. Baker’s yeast also known as Saccharomyces cerevisiae is used in bread baking and other wheat based products. Yeast of the same genus like Saccharomyces carlbergensis is also used in fermentation procedures for alcohol production. Though many mushroom species are edible there exist mushroom genera like Conocybe and Lepiota that are poisonous to humans and cause allergic reaction, hallucinations, organ failure and even death. Mushroom farming has grown into a strong industry that generates revenue and provides jobs. Fungi are partially responsible for the decomposition process. Actinomycetes and Basidomycetes and Zygomycetes are able to degrade plant and animal remains. Fungi especially Actinomycete decomposers are capable of breaking down tough compounds like cellulose lignin and chitin, they are therefore important in the decomposition chain. Other fungi like white rot, has been seen to degrade fuels, insecticides and other synthetic products into carbon dioxide and water. These fungi are useful in the bioremediation of polluted environments. Bio control is the use of one organism to kill another and it aims to reduce the activity of the harmful organism. In agriculture fungi have been used for bio control of agricultural plant pests and diseases. Two yeast species Pichia inositovora and P. Acaciae produce antifungal proteins that inhibit other yeasts. The produced toxins have been implemented in bio control of harmful yeast. Verticillium is also used in the control of cotton wilt and Sphaerellopsis is used in the control of plant rust diseases. A good example is the use of Beauveria bassiana in control of grasshoppers. The fungus infests the animal, and overwhelms the insects immune response and eventually kills it. Hirsutella infects citrus mite larvae as seen in picture below. Fungi also cause a number of diseases in man animals and plants. This results in damage harvests, diseases and loss in yield and even in life. Fungi that infect post harvest grain produce toxins that make the grain unsuitable for human consumption. A good example is aflotoxins produced by Aspergillus species which infect cereals like maize. A number of species cause large negative consequences in crop farming. Several species of Aphyllophorales cause harmful plant rot diseases. Fusarium species cause fusarium wilt which attacks a broad range of plants, bananas, tomatoes, potatoes, pepper among others and result in agricultural losses. Some fungal species especially moulds, are responsible for food spoilage. And this usually results in damage of large quantities of stored foods. Other fungi like Pithomyces chartarum causes facial eczema, a disease that affects sheep and is characterized by photosensitivity of the skin. The disease advances to produce toxins that damage the sheep’s liver. Athletes’ foot and Candida are good examples of human fungal infections. Fungi have industrial uses that involve the production of commercial products like garlic acid, ethyl alcohol, gluconic acid which have important industrial and domestic uses. Fungi contribute to soil fertility through the nitrogen cycle. Mycorrhiza is a symbiotic fungus that exists in the roots of vascular plants. In this association the fungus obtains carbohydrates like glucose, from the plant. The plant in turn gains the mycelium’s higher absorptive ability for nutrients and water due to the increase surface area for absorption. This improves plants mineral absorption. It has been observed that plants containing mycorrizium are resistant to soil borne pathogens. Such plants have also been found to be resistant to toxicity effects face in acidic and contaminated soils. An example of fungus that confers these advantages to plants is Pisolithus tinctorius. As explained above, fungi play a very crucial role in ecosystems. They have strong biological, medical, agricultural and economic importance. They act as plant and animal pathogens; they contribute to soil fertility, human health through the production of antimicrobials, plant resistance, decomposition and bioremediation. Fungi also produce essential industrial products like acids, proteins, vitamins and other supplements that are essential for human heath. BACTERIA SECTION 1. Microscope Calibration and size of Micro-organisms a. A student calibrated a microscope using the X100 oil immersion objective. On doing this, he found that the 80 eyepiece gratitude divisions corresponded to 100 micrometers on the calibration slide. Therefore; 80 eyepiece corresponds to 100 micrometers, how many micrometers does 1 eyepiece division correspond to? 80-100 1 - ? 100/80=1.25 1 eyepiece division corresponds to 1.25 micrometers. b. A circular bacterial colony growing on the surface of agar in a petri dish is 2mm in diameter and 0.5mm in height. The colony consists of cocci and each cell is 1 micrometer in diameter. Approximate number of cells in the colony will be: = volume of colony/ volume of a single cell. Volume of colony=πr2h =3.14 x (1x103)2m x (5x102)m = 1.57x109 m3 Volume of single cell= 4/3 πr3 = (4/3) x 3.14 x (5x102)3 m = 5.23x108 m3 = (1.57x109 m3)/ (5.23x108 m3) = 3.0019 There were approximately 3 cells 2. Bacterial identification and classification Gram stain reaction The gram stain reaction is one of the most used methods of identifying bacteria. In this procedure the bacteria is stained and examined under the microscope. A loopful of sterile distilled water is placed onto a microscope slide. Touch an inoculated colony with the inoculating loop and swirl it in water drop on the slide. Let the smear dry at room temperature. Heat fixes the smear by waving the slide over a flame. The slide should then be flooded with crystal violet and left to stand for one minute. The slide is then washed with cold water and flooded with gram’s iodine. This is then left to stand for one minute and washed off with water until the solvent flow is colourless. The slide is then flooded with safranine and let to stand for thirty seconds then washed off with water. The slide is blot dried with bilbous paper. This is then examined under a microscope. Gram positive organisms will appear purple while gram negative organisms will appear pink. Streak-Plate Method This method involves spreading bacterial cells over the surface of an agar plate in a continuous dilution to allow the cells to separate from each other. Upon incubation individual cells will grow into colonies that originated from a single cell. Firstly heat sterilizes the inoculating loop. Dip the loop into the culture broth touching the colony lightly with the loop. Then spread the culture over the surface of the Petri plate containing culture media. First streak a quarter of the plate, turn the plate 90 degrees and streak another quarter.. Sterilize the inoculating loop and continue to streak in to the next quadrant. Repeat the sterilization and streaking steps until the streaking pattern is achieved. The result should be as in the diagram below Incubate the plate under optimum conditions depending on bacterial culture. Observe the plates for growth of colonies. Bacterial colonies of different species have unique characteristics. Catalase Test This procedure tests for the presence of catalase enzyme present in most bacteria capable of breaking down hydrogen peroxide to form oxygen bubbles. Place a drop of 3% hydrogen peroxide onto a clean microscope slide. Use the inoculating loop to touch an isolated colony. Place the loop containing the isolate into the drop of hydrogen peroxide. Observe under a microscope for the evolution of bubbles. A positive result is confirmed by the rapid formation of oxygen bubbles. Oxidase Test This Procedure tests for the presences of the enzyme cytochrome oxidase. The enzyme oxidizes N,N,N',N'- tetramethyl-p-phenylenediamine dihydrochloride, the oxidase reagent, from colourless to purple. A piece of filter paper is placed on a clean microscope slide. 2 to 3 drops of the oxidase reagent is placed onto the filter paper. Touch an isolated colony with a wooden applicator stick. Place the end of the stick carrying the isolate onto the reagent saturated filter paper. Observe for the appearance of a dark purple colour. The reaction is positive if the smear turns purple within 10 to 30 seconds. 3. Bacterial growth in liquid culture a. Bacterial growth curve The y-axis shows the number of viable bacteria and the x-axis shows the time taken to achieve the number of bacteria in the culture. b. Methods of measuring bacterial growth There are several methods of measuring bacterial growth. One can take the counting colonies approach. This method is usually used to measure the growth of bacteria in a liquid culture. Take a portion of the liquid culture and dilute it first. You then spread some of this liquid on the plate, the agar plate. In normal cases, the cells will each make a colony which can easily be counted. The number of colonies will indicate the possible number of cells that were present. If the amount of liquid used is monitored and the dilution factor given, the number of cells in the original liquid culture can be calculated. This can be done by using a simple formula: Number of colonies counted x the dilution factor x the dilution factor of the plate. This formula gives you the number of units forming colonies in a millimetre in the starting culture. c. Calculation of the mean generation time The experiment started with 4x106 cells. After 248 minutes, the cells were 3x109 per ml. The mgt= (log10 (3x109) - (log10 (4x106)) / log10 4.1 hrs = (9.5 – 6.6) / 0.6 = 4.8 generations in 4.1 hours =4.1/4.8 = 0.85 hrs x 60 = 51.25 minutes d. Graph Time (mins) 0 150 200 250 280 310 340 370 400 Bacteria (millions/ml) 2 14.1 38.9 104.7 190.6 346.7 616.5 794.2 812.7 log of Bacteria (millions/ml) 0.3 1.15 1.59 2.02 2.28 2.54 2.79 2.99 2.9 The mean generation time (g) = (log10 Nt – log10 N0 / log102 = (log10 3 - log10 0.3)/ log10 2 = (0.477 - -0.523) / 0.301 = 3.32 minutes The above graph of bacterial colonies against time, the graph does not show a lag phase. During this experiment, the bacterial cells adapted well to the culture and the growth conditions thus there was no lag phase. The bacteria cells went straight into the exponential phase which is characterized by cell doubling. The stationery phase is reached but it did not last for long, the cells went into the death phase. Read More