2. After contact with a patient's spinal fluid, a lab technician developed fever, nausea, and purple lesions on her neck and extremities. A throat culture grew gram-negative diplococci. What is the genus of the bacteria?
3. Define and describe, in reference to the lifecycle of the liver fluke Clonorchis sinensis, the intermediate host and definitive host. Also name the phylum and class that this animal belongs to.
5. List the experimental requirements of Koch's postulates, and explain the exceptions to the requirements.
6. Given the limitations of Koch's postulates, what role do you see for molecular genetics and associated techniques in addressing the exceptions to the postulates?
7. Cancer patients undergoing chemotherapy are normally more susceptible to infections. However, a patient receiving an antitumor drug that inhibited cell division was resistant to Salmonella. Provide a possible mechanism for the resistance.
8. Describe the mode of action of each of the following antibiotics and explain what effect each one may have on host cells. Give an example of an organism that would be effectively treated for each drug.
4. polymyxin B
Describe the use of a DNA probe and PCR for:
Rapid identification of an unknown bacterium.
Since we are starting from an unknown bacterium, one can quickly isolate the DNA from a culture of the bacterium. Then use PCR method to quickly sequence various regions from the DNA and compare its DNA sequence profile to known profiles of bacteria for identification. In such a PCR method, one can use a degenerate primer for the PCR reaction or an array of specific primers. This is similar to the method forensic scientists use to identify potential criminals.
Alternatively, one can do some kind of Southern blot with an array of DNA probes to various different strains of bacteria. Whichever probe is able to hybridize or interact with the DNA sample, then that is the bacterium.
Determining which of a group of bacterium are most closely related.
Similar to the previous situations, one can use degenerate primers or an array of specific primers for various genes in the bacterial DNA in a PCR reaction to generate a genetic profile for each member of the group. Then, one can compare the genetic profiles to identify the ones that share the most genetic info.
Alternatively, one can do a genomic Southern with DNA probes against various crucial genes in the bacteria. The bacteria with the most similar hybridization patterns are likely to the most closely related ones.
After contact with a patient's spinal fluid, a lab technician developed fever, nausea, and purple lesions on her neck and extremities. A throat culture grew gram-negative diplococci. What is the genus of the bacteria?
Define and describe, in reference to the lifecycle of the liver fluke Clonorchis sinensis, the intermediate host and definitive host. Also name the phylum and class that this animal belongs to.
The egg of a Clonorchis sinensis contains the miracidium that develops into the adult form and floats in freshwater until it is eaten by a snail. Once inside of the snail body (intermediate host), the miracidium hatches from the egg, and parasitically grows inside of the snail. The miracidium develops into a sporocyst, which in turn houses the asexual reproduction of redia, the next stage. The redia themselves house the asexual reproduction of free-swimming cercaria. This system of asexual reproduction allows for an exponential multiplication of cercaria individuals from one miracidium. This aids the Clonorchis in reproduction, because it enables the miracidium to captilatize on one chance occasion ...
Discussion Question: Use of hypotheses and hypothesis testing
See attached article.
Review the following articles given under your week 1 Articles - Electronic Reserve Readings link, and write a short synopsis (200 -300 words) of the main points and learning takeaways. In your response, refer to your Seward text readings for week 1, to support your analysis.
THE PURPOSE OF HYPOTHESES
Hypotheses are the central tool of scientific observation. Because the core method of scientific investigation is the comparison of expectations against observations of the world, scientists need to make clear statements about their expectations. A hypothesis is a concise, falsifiable statement that is subjected to observational testing as part of a scientific investigation.
Scientific research generally starts with a question about the observable world. In the social sciences research questions focus on human behavior—especially behavior related to groups (e.g., communities, countries, or societies). The scientific method says nothing about the origins of these research questions (just as it says nothing about the content of the areas of research). The scientific method simply requires that a scientist state an answer to this question (the hypothesis) that can be tested with observations (hypothesis testing).
There is a bewildering array of potential research questions—and thus hypotheses—in the domain of social science. Hypotheses can focus on expectations about voting behavior, the tendency of nations to go to war, or the factors that contribute to juvenile delinquency or to decisions about where to live (among many, many other hypotheses).
The purpose of the hypothesis is to ease the task of testing an expectation with observations of the world. A good hypothesis, then, is one that is easily tested. The ease of testing contributes to a second key aspect of the scientific method: reproducibility of testing. A clearly worded hypothesis can be tested repeatedly by a scientist and, maybe more important, by other scientists (King, Keohane, and Verba 1994, pp. 28-29).
Consider the following example. A social scientist may hypothesize that smaller class sizes in secondary schools will lead to higher performance on standardized tests. Because it is easy to observe the number of students in a class and the standardized tests scores are also easily observable (though there may be questions of the validity of the test as a measure of "intelligence" or even "academic achievement"), this hypothesis is easy to test. The test itself is also easy to replicate by the original social scientist or by other investigators. The hypothesis is sufficiently clear that any observer would be able to tell whether people in the smaller classes actually performed better on standardized tests. The judgment, then, is not a product of the specific observer but is instead independent of the identity of the scientist (a subject of some controversy that is discussed in a later section).
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