Koch Post. answers

Koch Post. answers - Instructor Copy: Koch's Postulates,...

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1 Instructor Copy: Koch’s Postulates , the Scientific Method, and Infection in Potatoes Read about Koch’s Postulates in your textbook on page 579. On pages 1081-1082, you can read about Koch’s Postulates and What Causes Stomach Ulcers? Read page 1 and fill in the blanks at the bottom of the page. Microorganisms that cause diseases are called pathogens. These pathogens can be isolated today, much in the same way as Robert Koch established many years ago. In this lab, you will be the scientist responsible for testing a specific microbe , Erwinia carotovora , using Koch’s Postulates. It is important to note that the microbe with which you will be working is not pathogenic to humans; it cannot make you sick. This microbe is a pathogen only to plants such as potatoes. It causes a plant disease called “soft rot.” As long ago as the 16th century, it was thought that something unseen could cause disease. Even in ancient times, it was recognized that diseases could be contagious . Individuals with leprosy were segregated from healthy people. In 1876, Robert Koch was studying a disease of cattle called anthrax, and found convincing evidence that the disease was caused by a bacterium that was named Bacillus anthracis . In studying this disease, he established criteria and a method for determining whether a microorganism actually causes a disease. This method is called Koch’s Postulates. In 1876, Koch observed that cows infected with a disease called anthrax had millions of bacteria in their blood. He hypothesized that the bacteria found in the blood of the sick cow caused the disease. To test his hypothesis, he isolated bacteria from the host (the organism harboring the microorganism) and grew it in the laboratory . He then inoculated a healthy cow with these suspected bacteria that had been grown in the lab. After some time the new host showed signs of the disease. He isolated the bacteria found in his new host and then compared it with the original bacteria and identified them to be the same. He concluded after many trials that specific bacteria did indeed cause the disease. In 1990, when stomach ulcers, long accepted and treated as the result of excess stomach acid , were shown by Koch’s Postulates to be caused by the bacterium Helicobacter pylori . ( Sadava, et al , 579) Two scientists, Marshall and Warren, concluded that antibiotic treatment eliminated the bacteria and the inflammation in the host. The experiment was repeated on healthy volunteers and many patients with gastric ulcers were cured with antibiotics . How would you show results for each of the postulates based on the following statement? Stomach inflammation leading to ulcers is caused by H.pylori infections in the stomach. ( Sadava, et al, 1082) Marshall used himself as the test subject. Postulate 1
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Koch Post. answers - Instructor Copy: Koch's Postulates,...

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