Essay on Serial Dilutions

Three ways to assess water are positive/negative, membrane filtration and IDEXX Colilert and Enterolert assays. For membrane filtration, petri dishes and an incubator are used. For IDEXX coliert powdered medium is used for total coliform and E. Coli, while Enterolert media is used for enterococci. Also an incubator, colilert trays are used. IDEXX is more expensive than membrane filtration.

We set up 3 fermentation set-ups, labeling them 1, 2, and 3. Then, filled a tub with hot water and inserted the end of the plastic tubing into one of the test tubes and submerged the collection tube and plastic tubing in the tub. After that, we mixed the fermentation solutions for the other tubes, (tube 1 got 4mL of water and 3mL of corn syrup, tube 2 got 3 mL of water, 1 mL of yeast and 3 mL corn syrup, tube 3 got 1 mL water, 3 mL yeast and 3 mL of corn syrup) . We then mixed each test tube and put the rubber stoppers in the fermentation tubes. Finally, we marked the water level on each collection tube with a wax pencil to use as the baseline. Then at 5 minute intervals we measured the distance from the baseline for 20 minutes.

In everyday life we run into millions of microbes. Some of the bacteria is capable of making humans sick. The study of microbes has become very important subject to help stop potential pandemics and ensure proper hygiene. Anthony van Leeuwenhoek was the first scientist who discovered bacteria. In my study of microbiology, I got to choose an unknown bacteria to identify. It is important to start off finding the family of the unknown bacteria and then eliminating one by one the species to know which bacteria it is. By knowing the family, a scientist can save themselves a lot of time by knowing which tests need to be performed for the elimination process. This might seem like a waste of time to one but being able to correctly identify bacteria

For many years the identification of microorganisms has been important in the world of medicine. It is essential or correct disease diagnosis in patients and for proper treatment. Knowing the correct identity and characteristics of microorganism is crucial when disease outbreaks occur in populations, also knowing how humans can benefit from microorganisms is important; many can be used in making certain foods or antibiotics.

Often scientists work with bacteria that do not come in a labeled test tube— for example, bacterial samples taken from infected human tissue or from the soil—and the scientist must then identify the unknown microorganism in order to understand what behavior to expect from the organism, for example, a certain type of infection or antibiotic resistance. However, because of the relatively few forms of bacteria compared to animals and because of the lack of bacterial fossil records due to their asexually reproductive nature, the taxonomy used to classify animals cannot be applied to bacteria (Brown 275). In order to classify unknown bacteria, a variety of physiological and metabolic tests are available to narrow a sample down from the fathomless number of possibilities into a more manageable range. Once these tests have been performed, the researcher can consult Bergey’s Manual of Determinative Bacteriology, a systematically arranged and continually updated collection of all known bacteria based on their structure, metabolism, and other attributes.

The identification of unknown organisms carries important ramifications that can be applied to many real world scenarios. In keeping with quality assurance beverages, food, cosmetics, and other products are frequently inspected for contaminants resulting from a presence of pathogenic bacteria. In medicine, a physician’s diagnosis and consequent treatment is largely determined from samples collected from infection sites that have been analyzed using microbial tests.

# of plaques/(volume plated x reciprocal of the dilution factor of the dilution tube used)

The identification of unknown bacteria are used in labs by microbiologist for the purpose of studying bacteria that cause diseases, diagnosis of diseases and for treatment of the diseases. Therefore, it is important for them to effectively identify the right bacteria that is causing harm to people, animal or environment and treat it successfully. Hence, discussing the different type of test used and the processes of how one could identify the unknown bacteria.

Bacteria are identified systematically by using various different techniques and narrow down their species present in an unknown bacterial culture. This is highly usefully in identifying infections correctly and in research regarding microorganism. Laboratories use identification techniques based on primary characteristics and gram stains to carefully identify unknown organism in samples collected (faeces, blood, sputum, mucosal swabs), to determine the cause of infection and define a disease.

As said above, bicep workouts are all about curl. As the name suggests concentration curls can help you emphasize on your biceps solely. Since there are no other muscles involved in this workout, it is advised that you attempt these at the end of your workout plan.

In the 10-3 pasteurized sample, the plate exhibited 71,000 cells/mL. The results of the additional dilution samples contained too few colony forming units to count. However, in the 10-7 dilution, although the plate demonstrated 12 colonies, there should have been no colony forming units on this plate. The reasons for this could have been that this sample was contaminated from “double-dipping” the sample before dispensing it onto the plate or when using the pipette, it mistakenly was inserted in a higher concentration sample and then immediately to a lower concentration sample before it was dispensed onto the plate.

4. Prepare a vacuum filtration apparatus using a buchner funnel. Obtain one filter paper for each one of your samples, weigh them and record their mass in your notebook (label them with a pencil to be able to differentiate them later).

Preparing serial dilutions of the alfalfa water will ensure an accurate count. The plates are incubated until you see visible colonies, usually 18-24 hours. The colonies you see growing on the plate are considered to have started from one viable bacterial unit but because bacteria are usually not found as individuals, the colony you see may have started from a single cell or a group of cells. The results are reported as colony forming units (CFU’s).

In order to obtain well-isolated discrete colonies, the quadrant streak and spread technique was used. This allowed dilution of the original microbial material over the entire surface of the plate. As the original sample was diluted by streaking and spreading it, over successive quadrants the number of organism decreases. Usually by the third or fourth quadrant only a few organism were transferred on the by the inoculating loop and theses produce a few isolated

Collect to 2 large beakers both large beakers are to be filled with hot water (labtutor). Then obtain seven conical tubes these will be used to collect the levels of gas, you will also need test tube a stopper and a plastic tube (labtutor). You want to fill the conical tube to at least 50 ml of water (Cressy). Take the four conical tubes filled with water and place two in each beaker, to do this you must invert the tube and cover the release hole as to not lose any water (Cressy). Then place the beakers with the tubes in the bath so they can be at the same temperature as the bath (Cressy). Next mark all of your test tubes in number order to be sure which tube contains what concentrations and pH (Cressy). Having mixed a solution to the specifications of 2.5 ml of glucose in all tubes, 3 ml of yeast in 2 tubes of pH 5, 2 tubes of pH 9, and the single pH 7 tube, the remaining two tubes will contain no yeast as they will be negative controls. Next add 2 ml of pH buffer 3 tubes will receive pH of 5, three will receive a pH of 9 and a single tube of pH 7. Finally add pure water to make sure all test tubes have 10 ml of solution. When making the solutions