Domains-Kindoms-Phyla OH MY!

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The three domains in the tree of life are Bacteria, Archaea, and Eukarya.

• Domains are above the kingdom level. – proposed by Carl Woese based on rRNA studies of prokaryotes– domain model more clearly shows prokaryotic diversity

A bit more Accurate?

Why 3, or any domains?

• Domain Bacteria includes prokaryotes in the kingdom Bacteria.

– one of largest groups on Earth– classified by shape, mode of

nutrition, need for oxygen, and diseases caused

– 3.5 billion years old, so evolution has been extensive

Bacteria are members of the domain Prokarya and are in a kingdom of their own: Bacteria

Bacterial cells are typically smaller than eukaryotic cells

Bacterial cells are found in a variety of shapes: coccus, bacillus, spirillium, vibrio

Bacterial cells can cluster together: diplo, strepto, staphylo

Bacterial cells have murein walls, cell membranes, 70S ribosomes in cytosol, and a nucleoid with naked circular DNA

Bacteria lack nucleus, mitochondrion, or chloroplast

Bacteria have many modes of nutrition within: photoautotrophic, chemoautotrophic, photoheterotrophic and chemoheterotrophic

Bacteria can do photosynthesis, respiration and fermentation depending upon species

Bacteria became endosymbionts in ancient times and evolved into chloroplasts and mitochondria

Bacteria can grow very rapidly, dividing every 20 minutes, doubling in both size and number

Bacteria move using flagella made of flagellin, but other methods of locomotion are also known

Bacteria reproduce by cell division: known as binary fission...not mitosis!

Bacterial recombination is achieve by conjugation, but bacteria can receive foreign DNA by transformation and transduction

Bacteria respond to light (phototaxis), food (chemotaxis), magnetic field (magnetotaxis), and to each other (conjugation)

– known for living in extreme environments

• Domain Archaea includes prokaryotes in the kingdom Archaea.

– cell walls chemically different from some bacteria

– differences discovered by studying RNA

Archaebacteria;• developed about 3.5 billion years ago and like to live in

enviroments like early earth• are prokaryotic• live in extreme enviroments such as deep sea vents, hot

springs or salty places• are all chemoautotrophic• are anerobic• are unicellular• Lack the peptidoglycan of eubacteria.• Have different membrane lipids than eubacteria.• DNA sequence of archaebacteria is more like those of

eukaryotes.• Based on DNA evidence, scientists have suggested that

archaebacteria may be the ancestors of eukaryotes.

• Domain Eukarya includes all eukaryotes.

– kingdom Protista ?????http://en.wikipedia.org/wiki/Protist

– kingdom Plantae– kingdom Fungi– kingdom Animalia

Bacteria & Disease• Pathogen - a disease causing agent.• Bacteria are harmful because they damagetheir host's tissues by:

• a direct attack on the host's cells.• releasing poisonous toxins.

• Heat and cold help protect food from bacterialcontamination.• Pasteurization is a common industrial practice thatinvolves heating the product to a temperature thatkills most bacteria.

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Bacteria and DiseaseDisease Pathogen Areas

affectedMode of transmission

Botulism Clostridium botulinum Nerves Improperly preserved food

Cholera Vibrio cholerae Intestine Contaminated water

Dental Caries Streptococcus mutans, sanguis, salivarius

Teeth Environment to mouth

Gonorrhea Neisseria gonorrhoeae Urethra, fallopian

Sexual contact

Lyme disease Berrelia burgdorferi Skin, joints Tick bite

Rocky Mountain SF

Rickettsia recketsii Blood, skin Tick bite

Salmonella Salmonella Intestine Contaminated food, water

Strep throat Streptococcus pyogenes URT, blood, skin

Sneezes, coughs, etc.

Tetanus Costridium tetani Nerves Contaminated wounds

Tuberculosis Mycobacterium tuberculosis Lung, bones

coughs

Bacteria Spreads• By Air - airborne water droplets– sneezing, coughing, spitting - Most airborne diseases affectthe respiratory tract– Ex. TB, scarlet fever, whooping cough• By Sexual Contact– Ex. syphilis• By Insects– Examples• Lice- typhus• Ticks- Lyme disease• Fleas- carry bacteria that causes the Plague or “Black Death”• By Touch– Ex. Leprosy, Staph infections• By Contaminated Food/Water– Ex. Cholera, Salmonella and E-coli

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Helicobacter pylori is the pathogenic

bacteria that can causes stomach

ulcers

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Leprosy, caused by

Mycrobacterium leprae is a

bacterial infection that decreases

blood flow to the extremities

resulting in the deterioration of toes, ears, the nose and the

fingers.

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BOTULISM

Clostridium botulinum is an anaerobic bacteria that can sometimes grow in improperly canned foods. The toxin produced, is oderless and tasteless and can cause flaccid paralysis and death.

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CHOLERA

Cholera is caused by Vibrio cholerae a bacteria which commonly can be found in shellfish.

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DENTAL CAVITIES

Cavities are caused a bacterium found in your mouth called Streptococcus mutans which thrives on the sticky film called plaque. So brush your teeth!

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LYME DISEASE

Lyme disease is caused by Borrelia burgdorferi which is a bacterium that can be transmitted via the deer tick!

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SALMONELLASalmonella poisoning can be caused by the bacterium Salmonella spp. Can be found in some undercooked chicken, reptiles, eggs, etc.

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STREP THROAT

Strep throat is caused by Streptococcus pyogenes, a bacterium that can inhabit the back of the throat, the tonsils and the respiratory tract.

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TUBERCULOSIS

Caused by Mycrobacterium tuberculosis. Complications include chronic weakening of the lungs, damage to other organs, and death.

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Common AntibioticsAntibiotic Mechanism Target bacteria

Penicillin Inhibits cell wall synthesis Gram Positive

Ampicillin Inhibits cell wall synthesis Broad spectrum

Bacitracin Inhibits cell wall synthesis Gram Positive – Skin Ointment

Cephalosporin Inhibits cell wall synthesis Gram Positive

Tetracycline Inhibits Protein Synthesis Broad spectrum

Streptomycin Inhibits Protein Synthesis Gram Neg. tuberculosis

Sulfa drug Inhibits cell metabolism Bacterial meningitis, UTI

Rifampin Inhibits RNA synthesis Gram Pos., some Neg.

Quinolines Inhibits DNA Synthesis UTI

Problems with Antibiotic Resistance• Bacteria reproduce quickly.– They mutate.• Antibiotics kill most of the harmful bacteria.• The few that survive will reproduce and are resistantto the antibiotic.• People cause Antibiotic Resistance– Overuse of antibacterial products.– Overuse of antibiotics, not finishing the full courseof treatment.– Use of antibiotics in our food supply - cattle,poultry etc.

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Viruses and Human Disease

Control and Prevention of spread. Vaccination & Antiviral drugs

Ex.) chickenpox vaccine, AZT, Acyclovir, protease inhibitors.

Emerging Viruses – exist in isolated habitats Do not usually infect humans unless

environmental conditions favor contact. Several viruses are now linked to cancers

such as leukemia, liver cancer, Burkitt’s lymphoma, cervical cancer.

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Jenner was a doctor in the 1700's and found that a certain milkmaid was immune to smallpox she worked around cows who had cowpox So he was able to develop a vaccine based on this information.

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This was the first kid who got smallpox vaccine which eventually led to the eradication of smallpox

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Dead viruses, vaccines, are injected into a healthy person which activates the immune system. This causes the immune system to have a 'memory' for detecting this harmful virus. If the person comes in contact again with the virus, the immune response is faster.

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HERPES VIRUSES

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After polio infections, the killer T-cell have destroyed the motor

neurons that are producing the virus. The result is a loss of

muscle control including the

diaphragm. The iron lung changes the pressure to pump air

in and out of the lungs.

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Which US President had polio?

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F.D.R.

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MYXOVIRUSES

BACK

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RHABDOVIRUSES

BACK

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RETROVIRUSES

BACK

An exception to the central dogma. Rna to Dna

AIDS- acquired immuno deficiency syndrome

Attacks your immune system

EBOLA virusEbola is the virus Ebolavirus (EBOV), a viral genus, and the disease Ebola hemorrhagic fever (EHF), a viral hemorrhagic fever (VHF). The virus is named after the Ebola River Valley in the Democratic Republic of the Congo (formerly Zaire), which is near the site of the first recognized outbreak, a mission hospital run by Flemish nuns, in 1976Hemorrhagic fever is serious and deadly. It can cause bleeding from orifices and can be transmitted through saliva and blood

References:

http://kdhellner.tripod.com/id15.htmlhttp://plantphys.info/organismal/lechtml/bacteria.shtml