BIO 2924: Microbiology (Online) Dr. Seema Endley Mississippi Gulf Coast Community College Page 1 of 4 Critical Thinking Exercise General Guidelines • All submissions must be ORIGINAL. Answer each assignment IN YOUR OWN WORDS. • All submissions will be run through a plagiarism detector and evaluated for originality. Do not copy-paste material from Wikipedia or other websites. • An expected word count is given for each assignment. If your submission is shorter you may lose points. Be sure to include the word count in each section. • Make your submission in one file. • Submit your document in one of the specified formats. If I cannot open your document, I cannot grade it. Acceptable formats are RTF, DOCX, DOC, TXT, & PDF. I do not have a Mac, so if you are working on a Mac, be sure to save it in a format that is portable, such as PDF. Assignment 1 (25 points) Word count: 150 or more per microorganism Pick FIVE (5) beneficial microorganisms that are of environmental and/or commercial importance, and, IN YOUR OWN WORDS, briefly describe their benefit. Each microorganism should belong to a different genus. For example, Lactobacillus casei and Lactobacillus acidophilus belong to the same genus, so you can pick only one of them. Assignment 2 (50 points) Word count: 400 or more per disease Choose FIVE (5) diseases from the list provided below, and, IN YOUR OWN WORDS describe the following: 1. The name of the microbe causing the disease. Remember to mention what type of microbe it is (bacteria, virus, fungus, helminth, etc) 2. The nature of the disease? a. How does the disease manifest itself? For example, does the pathogen cause a respiratory disease, or a gastrointestinal disease, or a sexually transmitted disease, etc? b. What part of the human body gets affected by the disease? c. How does the microbe cause the disease? For example, does the microbe secrete a toxin, or does it behave as an intracellular pathogen, or does it cause hemorrhaging, etc? d. Where does the pathogen reside in the human body? For example, does the microbe live in the lung tissue, or the gastrointestinal tract, or the nerves, or in the blood, etc? e. How does the disease spread? For example, is the disease food-borne, or airborne, or sexually transmitted, etc? 3. The signs and symptoms of the disease? I have provided 2 examples at the end to give you an idea of how to proceed with the assignment. Please format your assignment keeping this format in mind. Also, read the examples carefully as I have chosen diseases that have been or will be covered in various topics during the course of this semester. BIO 2924: Microbiology (Online) Dr. Seema Endley Mississippi Gulf Coast Community College Page 2 of 4 List of Diseases 1. Syphilis 2. Leptospirosis 3. Lyme disease 4. Legionellosis 5. Gonorrhea 6. Typhoid 7. Bubonic plague 8. Whooping cough 9. Tetanus 10. Tuberculosis 11. Leprosy 12. Toxic shock syndrome 13. Diptheria 14. Rabies 15. Chicken pox 16. Measles 17. HIV 18. Small pox 19. Hepatitis B 20. Giardiasis 21. Loaiasis 22. Rocky mountain spotted fever 23. Pneumocystis pneumonia 24. African sleeping sickness 25. Streptococcal (pneumococcal) pneumonia Bonus: Assignment 3 (25 points) Word count: 300 or more per scientist or a team Discuss and describe IN YOUR OWN WORDS the main contributions of FIVE (5) scientists (or a team of scientists) from the list given below. Describe the challenges they faced both in the laboratory, as well as in the society they lived and worked in, along with any controversies that plagued them during the course of their research. Also discuss how their contribution has changed the face of microbiology, and in what way has society benefitted from their work. 1. Alexander Fleming 2. Alfred Hershey and Martha Chase 3. Anton Von Leeuwenhoek 4. Barbara McClintock 5. Edward Jenner 6. Emil von Behring 7. Francesco Redi and Lazzaro Spallanzani 8. Francois Jacob and Jacques Monod 9. Fredrick Griffith 10. George Beadle and Edward Tatum 11. Ignaz Semmelweis 12. Ilya Ilyich Mechnikov 13. John Snow 14. Joseph Lister 15. Joshua Lederberg 16. Louis Pasteur 17. Luc Montaigner and Robert Gallo 18. Martinus Beijerinck and Sergei Winogradsky 19. Oswald Avery, Colin MacLeod and Maclyn McCarty 20. Paul Ehrlich 21. Robert Koch 22. Stanley Cohen, Annie Chang, Robert Helling and Herbert Boyer 23. Stanley Prusiner 24. Sydney Brenner, Francois Jacob and Matthew Meselson BIO 2924: Microbiology (Online) Dr. Seema Endley Mississippi Gulf Coast Community College Page 3 of 4 Example #1 Name of the disease: Variant Creutzfeldt-Jakob (vCJD) – in humans, Bovine Spongiform Encephalopathy or Mad Cow Disease – in bovines Name of the Causative Agent: The prion. Prions are not microbes. Prions are normal proteins of animal tissues that can misfold and become infectious: they are not cellular organisms or viruses. In their normal noninfectious state, these proteins may be involved in cell-to-cell communication. When these proteins become abnormally shaped i.e., infectious prions, they are thought to come into contact with a normally shaped protein and transform that protein into the abnormally shaped prion, like a bad apple ruining the good apples in the basket. This process causes a geometric increase of abnormally shaped prion proteins until the number of abnormally shaped protein causes overt illness. When consumed by animals, prions are thought to be absorbed into the body during digestion where they begin the process of changing their normal protein counterparts into abnormal proteins; however infectious prions from one species of animal have less of a potential of causing the abnormal shape in the normally shaped prion proteins of another species (the “species barrier”). While the “prion theory” of Transmissible Spongiform Encephalopathies (TSEs) is widely accepted, there are other theories of the cause of these illnesses. Nature of the Disease: Prions are associated with a group of diseases called Transmissible Spongiform Encephalopathies (TSEs). In humans, the illness suspected of being food-borne is variant Creutzfeldt-Jakob disease (vCJD). The human disease vCJD and the cattle disease, bovine spongiform encephalopathy (BSE), also known as “mad cow” disease, appear to be caused by the same agent. Other similar but not identical TSE diseases exist in animals, but there is no known transmission of these TSEs to humans. Included among these is chronic wasting disease (CWD) of deer and elk, and the oldest known of these diseases – scrapie – which occurs in sheep and goats. No early acute clinical indications for TSEs have been described. After an extended incubation period of years, these diseases result in irreversible neuro-degeneration. The neurodegenerative phase of vCJD in humans typically involves the formation of “daisy-shaped” areas of damage in the central nervous system. There is also, in common with other TSEs, vacuolization (formation of holes) that gives brain tissue a spongy Swiss-cheese like appearance when examined under a microscope. It is thought that the build-up of the abnormally shaped prion proteins causes the observed neuro-degeneration. Signs and Symptoms: Cases of vCJD usually present with psychiatric problems, such as depression. As the disease progresses, neurologic signs appear — unpleasant sensations in the limbs and/or face. There are problems with walking and muscle coordination. Sometimes, late in the course of the disease, victims become forgetful and then experience severe problems with processing information and speaking. Patients are hospitalized and are increasingly unable to care for themselves until death occurs. BIO 2924: Microbiology (Online) Dr. Seema Endley Mississippi Gulf Coast Community College Page 4 of 4 Example #2 Name of Disease: Ebola hemorrhagic fever (Ebola HF) Name of the causative organism: Ebola virus Nature of the Disease Infections with Ebola virus are acute. There is no carrier stage. Because the natural reservoir of the virus is unknown, the manner in which the virus first appears in a human at the start of an outbreak has not been determined. However, researchers have hypothesized that the first patient becomes infected through contact with an infected animal. After the first case-patient in an outbreak setting is infected, the virus can be transmitted in several ways. People can be exposed to Ebola virus from direct contact with the blood and/or secretions of an infected person. Thus, the virus is often spread through families and friends because they come in close contact with such secretions when caring for infected persons. People can also be exposed to Ebola virus through contact with objects, such as needles, that have been contaminated with infected secretions. Nosocomial transmission refers to the spread of a disease within a health-care setting, such as a clinic or hospital. It occurs frequently during Ebola HF outbreaks. It includes both types of transmission described above. In African health-care facilities, patients are often cared for without the use of a mask, gown, or gloves. Exposure to the virus has occurred when health care workers treated individuals with Ebola HF without wearing these types of protective clothing. In addition, when needles or syringes are used, they may not be of the disposable type, or may not have been sterilized, but only rinsed before reinsertion into multi-use vials of medicine. If needles or syringes become contaminated with virus and are then reused, numerous people can become infected. Ebola-Reston appeared in a primate research facility in Virginia, where it may have been transmitted from monkey to monkey through the air. While all Ebola virus species have displayed the ability to be spread through airborne particles (aerosols) under research conditions, this type of spread has not been documented among humans in a real-world setting, such as a hospital or household. There is no standard treatment for Ebola HF. Patients receive supportive therapy. This consists of balancing the patient’s fluids and electrolytes, maintaining their oxygen status and blood pressure, and treating them for any complicating infections. Signs and Symptoms The incubation period for Ebola HF ranges from 2 to 21 days. The onset of illness is abrupt and is characterized by fever, headache, joint and muscle aches, sore throat, and weakness, followed by diarrhea, vomiting, and stomach pain. A rash, red eyes, hiccups and internal and external bleeding may be seen in some patients. Researchers do not understand why some people are able to recover from Ebola HF and others are not. However, it is known that patients who die usually have not developed a significant immune response to the virus at the time of death.