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Slide 1

E. Coli Bacteria

Harmful Or

Harmless???

Slide 2 Is part of a Major Group of

Bacteria•• Phylum: Phylum: ProteobacteriaProteobacteria•• Class: Class: Gamma Gamma Proteobacteria Proteobacteria •• Order: Order: Enterobacteriales Enterobacteriales •• Family: Family: Enterobacteriaceae Enterobacteriaceae •• Genus: Genus: Escherichia Escherichia •• Species: Species: E. E. colicoli

SSttuuddeennttss sshhoouulldd aallrreeaaddyy hhaavvee bbeeeenn eexxppoosseedd ttoo tthhee CCllaassssiiffiiccaattiioonn ooff OOrrggaanniissmmss.. TThhiiss ggiivveess ssttuuddeennttss aa vviieeww ooff tthhee bbiigg ppiiccttuurree ooff oorrddeerr..

Slide 3 Enterobacteriaceae

A Large Bacteria Familywhich 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)

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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.

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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.

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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

48 – 72 Hours (depending on the purity of the

culture )

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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 48-72 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?

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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

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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!

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Slide 22 PART III

BIOSENSORS• Any ideas on an easier way to know

that our antibody has found the bacter ia/virus?

• What if – when the antibody f inds the bacte r ia/virus ………it comple te s an electr ical circuit?

Slide 23 Antibody + an electronic circuit

=

Slide 24 A Biosensor!!

Analyte is the liquid to be tested and is put on the application membrane.

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Slide 25 Analyte is the liquid to be tested and 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)

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Slide 28 The antibodies have been attached to

the polyaniline

Analyte is the liquid to be tested and is put on the application membrane.

Slide 29 Everything then flows into the Capture Membrane which is lined with

electrodes

Analyte is the liquid to be tested and is put on the application membrane.

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.

Analyte is the liquid to be tested and is put on the application membrane.

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Slide 31 The Capture Membrane also has some secondary antibodies attached to

polyaniline

Analyte is the liquid to be tested and is put on the application membrane.

Slide 32 The Capture Membrane is where the electrical signal is produced if the

antibody and antigen have found each other here!

Analyte is the liquid to be tested and is put on the application membrane.

Slide 33 The absorption membrane collects any

excess Analyte.

Analyte is the liquid to be tested and is put on the application membrane.

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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.

• http://www.cfsan.fda.gov/~lrd/ecoli.txt• http://textbookofbacteriology.net/e.coli.html• http://en.wikipedia.org/wiki/Escherichia_coli• http://textbookofbacteriology.net/Anthrax.html