Slide 1. Slide 2. Slide 3

Transcription

1 Slide 1 E. Coli Bacteria Harmful Or Harmless??? Slide 2 Is part of a Major Group of Bacteria Phylum: Proteobacteria Class: Gamma Proteobacteria Order: Enterobacteriales Family: Enterobacteriaceae Genus: Escherichia Species: E. coli Students should already have been exposed to the Classification of Organisms. This gives students a view of the big picture of order. Slide 3 Enterobacteriaceae A Large Bacteria Family which naturally live in the intestinal tracts of animals Salmonella Shigella Yersinia Escherichia Enterobacter Klebsiella Now we jump back up to the FAMILY of Enterobacteriaceae. All Enterobacteriaceae live in the intestinal tracts of animals, including humans. E. coli of course is in the Escherichia Genus (in bold) 39

2 Slide 4 Escherichia coli bacterium There are over 200 identified strains of E.coli The bacterium is constantly mutating, so new strains are always being found Most strains are beneficial and hamless. E. coli. Scanning E.M. Shirley Owens. Center for Electron Optics. Michigan State University. NOW WE UNDERSTAND THE E of E. coli bacteria! Slide 5 Most strains E.coli are beneficial to the health of mammals They break down and process food in the digestive tract. Often known as probiotics or beneficial flora in the digestive food industry Where ever they live, they are breaking down other harmful substances. Slide 6 But Sometimes these bacteria are associated with disease in human beings. 40

3 Slide 7 Negative strains of E.coli can cause Diarrhea Urinary Tract Infections Meningitis Peritonitis Mastitis Pneumonia Death Slide 8 Where is Escherichia coli bacterim found? A multitude of strains of good & bad E.coli live.. Lower intestines of mammals Feces of mammals Surface waters in the soil in and on all mammals (skin & fur) Why we wash our hands!!!!!! Slide 9 The strains of E.coli become harmful... In mammals, when they are no longer a part of the digestive tract (enter the blood streams through ulcers or perforations). If concentrations in water are so high that the statistical chance of a negative mutation is likely. They can infect you through cuts in the skin. If a negative mutation of E.coli enters food production through the soil or through the slaughtering of animals for meat. This is why we test water for e.coli concentrations in drinking water and at swimming lakes and rivers. Negative E.coli strains have injured and killed people through spinach, tomato and hamburger consumption. 41

4 Slide 10 A deadly mutation: E.coli 0157:H7 Low-temperature electron micrograph of a cluster of E. coli bacteria, magnified 10,000 times. Each individual bacterium is oblong shaped. NOTICE how the deadly mutation of E.coli is labeled Slide 11 Can cause in the young and the old (b/c their immune & digestive systems are not operating at a premium) Bloody diarrhea Kidney failure Average of 61 deaths per year in the U.S. (a developed country) You can get it from Undercooked, contaminated meat Person to person contact Contaminated fruits & vegetables (uncooked) Un-pasteurized milk Swimming in or drinking contaminated water. Slide 12 Current Detection Time for E.coli 0157:H7 is Hours (depending on the purity of the culture ) 42

5 Slide 13 Why would we want to improve upon this detection time? Because food products leave processing before a positive/negative detection can be found (to sell the food while it s still fresh). How many people could have been contaminated during the hours while the culture was grown? Slide 14 Your Assignment: Your group will be assigned just one bacteria or virus which we want to be able to detect with biosensors. Research your particular bacteria/virus & their anitbody! Slide 15 Questions you ll want to answer in your presentation: How long does it take for us to currently detect these bacteria/viruses? Do we have antibodies for all of these? Can we isolate the antibodies and use them to detect bacteria & viruses? 8Do the antibodies have to be made by a live animal, or can they be manufactured or bought from companies? 43

6 Slide 16 Your Presentation: Use poster board or if possible the stand up, 2- fold poster board so it will stand on its own OR.. do a PowerPoint Presentation Diagrams or photo s of their bacteria/virus and antibody are important. Utilize as much of the vocabulary from the chapter as possible in your presentation. TIME ALOTMENT: One block day of classtime if you are not finished you are on your own. Slide 17 PART II Slide 18 ANTIBODIES 44

7 Slide 19 How can antibodies help with detection of Bacteria & Viruses? Antibodies are protein molecules, usually developed by the immune system in mammals. The immune system uses the antibodies to identify and neutralize bacteria and viruses. For every bacteria or virus there is an antibody to identify & neutralize that bacteria or virus. Slide 20 What if We use the antibody to find the bacteria or virus. BUT How will we know that the antibody found the bacteria/virus???? Slide 21 What if We put some bacteria in a petri dish Some dishes will have the antibody in the dish, while other dishes will not. What should happen? What would our purpose or question be in doing this? Let s write this up & do it! 45

8 Slide 22 PART III BIOSENSORS Any ideas on an easier way to know that our antibody has found the bacteria/virus? What if when the antibody finds the bacte ria/virus it comple te s an electrical circuit? Slide 23 Antibody + an electronic circuit = Slide 24 A Biosensor!! 46

9 Slide 25 is put on the application membrane. How does this work if it s meat at the meat packing plant? Slide 26 The analyte flows into the Conjugate Membrane. Slide 27 In the conjugate membrane are the antibodies specific to the antigen (bacteria/virus) 47

10 Slide 28 The antibodies have been attached to the polyaniline Slide 29 Everything then flows into the Capture Membrane which is lined with electrodes Slide 30 The primary purpose of the Capture Membrane is to capture the antigen-antibody complex (if the antibody finds the antigen!) as it moves in from the capture membrane. 48

11 Slide 31 The Capture Membrane also has some secondary antibodies attached to polyaniline Slide 32 The Capture Membrane is where the electrical signal is produced if the antibody and antigen have found each other here! Slide 33 The absorption membrane collects any excess Analyte. 49

12 Slide 34 Current dilemmas & challenges? How do we get industry interested in manufacturing biosensors? Should biosensors be legislated as mandatory at food processing plants? How could this save or cost industry in dollars? Or should biosensors be left to personal use for an individual to have on hand an home? Others? Slide 35 References Alocilija, Evangelyn C., Biosystems Engineering, Michigan State University, Lansing, Mi