Bacteria, Archaea, Viruses

Which Kingdom do Viruses belong to?

Bacteria

• Single cell – unicellular• Prokaryotes – no nucleus, no organelles• DNA – circular - single loop + has many

plasmids• Cell Wall – not rigid like in plant, more flexible

– composed of peptidoglycan– can protect bacteria from hosts defenses– useful as a signal to other bacteria

Bacteria Structure

5.  Nucleoid region contains a circular loop of DNA

6.  Plasmids are rings of DNA, used in reproduction

7.  Ribosomes in cytoplasm synthesize proteins

2. Flagella is used for movement

3.  Pilli (Fimbrae) help bacteria cling to surfaces

4. Prokaryotes do not have organelles or a membrane bound  nucleus!

How do Bacteria Obtain Food

PhotoautotrophsChemoautotrophs

Heterotrophs

Photoautotrophs - cyanobacteria

Chemoautotrophs - sulfur-loving bacteria

• need CO2 as a carbon source

• obtain energy NOT from light

• obtain energy from oxidization of H2S, HN4, or Fe+

Heterotrophs

• Obtain their energy from organic compounds

• These are made by the photo- and chemo-autotrophs

Disease causing Bacteria• Cholera• Anthrax• Tuberculosis – TB• Pneumonia• Tetanus• Streptococcal diseases• Variety of infections – assosiated with other

diseases (post-operative, cold and flu- associated, etc.)

Archaea – ArchebacteriaAncient Bacteria

• At first believed to be weird bacteria• Scientific evidence tell us that they are very,

very old organisms – share characteristics with bacteria , BUT also characteristics with eukaryotes

• Life in EXTREME environments – places on Earth where they are the ONLY living thing

Archeae

• Unicellular prokaryotes (like bacteria)• Have a cell wall (like bacteria) BUT cell wall is

very different composition• Cell membrane is so different from bacteria

that antibiotics (which kill bacteria by affecting cell wall and membrane) have NO effect on archaebacteria

Origins

Archaea of Note• Lobus fulgidus is a sulfur-reducer that can sour oil

wells. • Halobacteria are salt-loving microbes that give a

pink tinge to salt water evaporation ponds, the Dead Sea and salted fish.

• Pyrolobus fumarii led scientists to extend the upper temperature limit for life to 113 degrees Celsius (235.4 degrees Fahrenheit).

• Sulfolobus acidocaldarius is used to leach copper and iron from ore.

Where do they live?

Ocean Vent

ice

sulfur Great Slat Lake

Geyser

THERMOACIDOPHILE – the red stuff on the rocksThis is an archaebacteria.

THE FUTURE//PAST BELONGS TO ARCHAE!

How weird can they get?

• Thermophiles like unusually hot temperatures. A few species have been found to survive even above 110 degrees Celsius (water boils at 100 degrees Celsius).

• Psychrophiles like extremely cold temperatures (even down to -10 degrees Celsius).

• Halophiles thrive in unusually salty habitats. Some can thrive in water that’s 9% salt; sea water contains only 0.9% salt.

• Acidophiles prefer acidic conditions; Alkaliphiles prefer very alkaline environs.

What do they Eat

• Hydrogen Gas• Carbon dioxide• Sulfur• sunlight – autotroph – light-harvesting

pigment in cell membrane

What is a virus?• A nonliving particle made of

protein, nucleic acids and sometimes lipids

• Viruses can only reproduce by infecting living cells!

• Viruses are parasites!

Viral Structure• Capsid-the protein coat

surrounding a virus

Viral Structure• Capsid can be different shape

and form• Bacteriophages –Viruses that infect bacteria

Viral Infections• Lytic Infection-

–Virus enters a cell–Makes copies of itself–Causes the cell to burst or lyse– Can the virus keep doing

this?

Viral Infections• Lysogenic Cycle

–Virus enters cell–Prophage- viral DNA embedded

in the host cell’s DNA–Virus is dormant – lays low

Virus Genetic material

• DNA Viruses and RNA Visruses

• Both types can have ss or ds DNA/RNA

• Some RNA viruses have enzymes that convert their RNA into DNA

Retrovirus• The genetic information is

copied from RNA to DNA instead of from DNA to RNA

• Example: HIV

Some Viral Diseases• Common Cold – many different viruses –

rhinoviruses (RNA), corona viruses, etc.• Flu – Influenza (RNA) virus• AIDS – HIV• Measels – Paramixovirus• Cold sores – Herpes virus• Mumps – Paramixovirus• many, many others

Some exotic ones

• West Nile fever – west nile virus• Hemorrhagic fever – many nasty viruses:

Ebola, Marburg, Lassa, Dengue, etc.• Tick-bore encephalitis – TBEV• 4-corners disease – Hanta virus (Hantavirus

Pulmonary syndrome)• More exotic ones appear – they jump hosts –

destruction of Rainforest??????

http://youtube.com/v/4sYSyuuLk5g

Outbreak Movie Trailer

Contaigon Movie Trailer

Ebola Oubreak

Useful Bacteria

• Many Bacteria are beneficial to humans, animals, plants, the environment – more and more bacteria are used to do strange things

• Check this out: Weird uses of Bacteria

Probiotics• Bacteria and yeast that are believed to

improve health• Available in certain foods or as supplements• Our digestive system is home to more than

500 different types of bacteria – keep intestines healthy and help with digestion, help immune system

• Probiotics may help treat several digestive disorders – Diarrhea, Colitis, Irritable Bowl syndrome, etc.

Probiotics

Auditions for Helpful Bacteria

And the winner is ........