Microbes like bacteria and viruses are part of our daily lives! Summary color is red; underlined words are vocabulary; hyperlinks in blue.

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In 2009 the world was introduced to swine flu (H1N1) which is caused by new strain of virus similar to the common cold; it quickly spread around the globe.

Tuberculosis, TB (shown here) hit Houston in 2013!

Microscopic life is everywhere, but not all microbes are deadly!

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The smallest and most common living microorganisms are prokaryotes (lack a nucleus and organelles). Unicellular (one cell)

Circular DNA called

plasmids Some have pili

and/or flagella"Typical blue-green alga and bacterial cells." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 4th ed. Detroit: Gale, 2008. Science in Context. Web. 14 Mar. 2014.

Electron micrograph of Martian meteorite ALH84001 showing structures that some scientists think could befossilized bacteria like life forms. Image

Bacteria comes in many shapes [the colors match the images]: Spheres (or cocci) Rods (or bacilli) Spirals (or spirilla) Chains (or strepto) Clusters/Groups (or staphlyo)

http://biology.clc.uc.edu/graphics/bio106/bacteria.jpg

Colored scanning, electron micrograph (SEM) of anthrax bacteria (Bacillus anthracis), the cause of the disease anthrax in humans and livestock. Anthrax is used as in bioterrorism.

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Bacteria reproduce in three ways:

1. Binary fission - asexual reproduction, cell divides producing 2 identical daughter cells

Video

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2. Conjugation - sexual reproduction that exchanges genetic material between 2 cells▪ Moves DNA between

cells, allows for genetic diversity

▪ Bacterial cells can mutate to create new strains

▪ Animationhttp://www.wiley.com/college/pratt/0471393878/student/activities/bacterial_drug_resistance/conjugation_web.jpg

3. Spores – some bacteria delayed reproduction, thick walls around their DNA called an endospore during unfavorable conditions; they can resist drought, heat, even radiation. When conditions

improve, the germinates endospore and the bacteria grows again.

An endospore. Bacillus anthracis, the bacterium that causes anthrax, produces persistent endospores. The thick, protective coat helps it survive in the soil for years. Image

Foods! EX cheese, yogurt , soy sauce, etc.

Some bacteria can remove waste products from water and sewage; bacteria has been modified to consume oil in oil spills. Bioremediation – process

of using microorganisms to help restore natural environmental conditions.

http://www.capetownskies.com/1058/25_oilspill_workers_closee.jpg

Some bacteria are producers and create oxygen and/or nitrogen used by some plants and animals.

As decomposers, they help to recycle nutrients into raw elements.

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A virus is an infectious agent with a core of genetic material (DNA or RNA) and surrounded by a protein coat [capsid] and lipid envelope. They are NOT cells

(no membranes or organelles)

Reproduce only within a host cell

Considered parasites Animation

http://visual.ly/node/25794

This diagram compares a human liver cell, a single ribosome, and a bacterium, to some common viruses.

Viruses are very very small (b/w .003 ~ .05 microns)!

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Viruses come in many shapes.

Viral shapes include: Helical a twisted

coil Polyhedral a

sphere surrounded by polygons; EX Herpes

Spherical EX Influenza

And others

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Viruses are very host specific; the protein arrangement [coding spikes] on the exterior recognize certain types of cells [like the lock and key model in enzymes].

http://legacy.uspharmacist.com/ce/105382/figure1.jpg

A virus needs a host to reproduce; they have to use a cell! A host is an

organism that shelters and nourishes something else (think hostess).

Viruses reproduce in three ways: Lytic Lysogenic Retrovirus

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Lytic Cycle – viral replication that rapidly kills a host cell

1.Virus attaches to cell and injects its genetic material

2.Tricks the host cell to make viral mRNA

3.Chops up [using enzymes] the cell’s DNA; assembles viral DNA

4.The cell now builds viruses

5.Cell lyses, or bursts6.Minion viruses infect

other cellshttp://www2.bc.cc.ca.us/bio16/images/lyticcycle.jpg

Lysogenic Cycle – the virus does not immediately kill the host cell [remains dormant] EX Herpes Viral genome inserts

itself into the hosts DNA [provirus]

Every time the cell divides, the “invading” virus’ DNA is copied

Eventually, the virus is activated and enters the lytic cycle

http://upload.wikimedia.org/wikipedia/en/thumb/0/0e/Viral_Reproduction_Chart.png/300px-Viral_Reproduction_Chart.png

The most complicated form of viral replication is the retrovirus; prefix retro means backwards from RNA to DNA EX HIV They produce a copy of DNA using reverse

transcriptase, an enzyme then Then follows the steps of lysogenic

replication

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Some bacteria and viruses [and other types of life] can be pathogens; some pathogens are deadly, some are not.

Epidemiologists are scientists who study the cause and spread of diseases [pathogens] through populations.

By doing this, scientists help prevent or control the spread of diseases; use this interactive to learn about common pathogens.

A nefarious baculovirus, that only targets the

gypsy moth caterpillar, infects it's host and

forces it to climb to the very top of a tree, before

liquefying it and showering deadly,

disease-ridden goo down onto the other

caterpillars below. Horror horror horror.

From Sinister Virus Image

Zombie Caterpillars Video

Viroids cause disease in plants Just a single strand of RNA molecule w/ no capsid

Prions cause disease in animals Just particles of protein EX Mad cow disease and Creutzfeldt-Jakob

disease may be caused by prions.

Potato spindle tuber viroid (PSTVd) in tomatoe plants. Image

Vaccines - stimulate the body’s immune system with antigens to prevent disease

Antibiotics - block the growth of bacteria They can be used to

cure and treat many diseases caused by bacteria that, in the past, have been deadly.http://www.biotechnologyonline.gov.au/images/contentpages/antibiotics.jpg

Vaccines - stimulate the body’s immune system with a harmless (weakened or dead) form of a virus to create antigens to prevent disease EX Flu shot,

chicken pox vaccine

Animation

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Modern bacteria have evolved! Disinfectants, antiseptics,

hand sanitizers and anti-bacterial soaps are designed to kill microbes.

Remember, however, the overuse of these products and antibiotics can cause the bacteria to mutate and become resistant and more dangerous and difficult to kill.

Super Germs Video

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