Bacteria

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Bacteria

• Prokaryotes are the most numerous organisms on
  Earth

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Prokaryotes

• Prokaryotes are single-celled organisms that do
  not have a membrane-bound nucleus
• They live in every environment on Earth
• They are a major source of food for many
  organisms
• They also help many organisms digest food

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General Characteristics

1. Unicellular
2. Prokaryotic
3. Nutrition modes mainly absorption, some
   photosynthetic, some chemosynthetic
4. Anaerobic and aerobic species
5. Reproduction fusion or budding
6. microscopic

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Carl Woese

• Discovered in the late 1970s that prokaryotes
  made up 2 of the 3 domains of life
• Categorized based on ribosomal RNA analysis

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2 Major Domains

• Archaea means archaic or ancient
• Bacteria

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Domain Archaea

• Not like bacteria, but more like Eukaryota
• Differ from bacteria in the make up of their cell
  wall, membrane lipids, their genetics
  metabolism
• Cell walls do not have peptidoglycan (a
  protein-carbohydrate compound)
• Cell walls have different amino acids and
  different types of lipids

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Truth about Archaea

• Archaea were first discovered in extreme
  environments like swamps, salt lakes and hot
  springs
• Recently, scientists found Archaea genetic
  materials in samples of surface water from the
  North Pacific Antarctic Oceans
• So, Archaea may be more common that once thought.

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3 Broad Groups of Archael Bacteria

1. Methanogens
2. Halophiles
3. Thermoacidophiles

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1. Methanogens

• Named for their unique way of getting energy
• Convert H2 gas CO2 into methane gas (CH4)
• Live in anaerobic environments)-like swamp
  bottoms (marsh gas), sewage, intestinal tracts of
  humans, cows, termites
• Oxygen is poisonous to them

A cow can belch 200 400 L Of Methane per day
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The methane that bubbles out at marshes are
called marsh gas
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2. Halophiles

• Salt Lovers-live in high salt concentrations
  like the Great Salt Lakes Dead Sea
• High salt concentrations would kill most bacteria
  but favor the growth of halophiles b/c they have
  adapted to live in very salty water
• Aerobic organisms

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• Ex Great Salt Lakes

• Ex Dead Sea

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3. Thermoacidophiles

• Live in very acidic environments that have very
  high temperatures (ph less than 2) with
  temperatures (230 F)
• Found in hot springs (Yellowstone National Park),
  volcanic vents, hydrothermal vents of the ocean
• Requires sulfur
• anaerobes

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• Hot Springs at Yellow Stone National Park

• Hydrothermal Vent

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Domain Bacteria

• Most well known prokaryotes
• General Characteristics
• 1. Largest group of bacteria
• 2. Occur in many shapes and sizes
• 3. Have distinct biochemical and genetic
  characteristics

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Domain Bacteria

• Occur in different shapes and sizes
• Identified by basic shapes

1. Sphere Coccus round
2. Rods Bacillus Rod Shaped
3. Spirals Spirillum

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Three Bacterial Cell Shapes
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Bacterial cells are also classified by their
arrangements

• Diplo Two
• Staphlyo Clusters
• Strepto Long Chain

Bacteria can occur in pairs diplo- bacilli or
cocci
Staphylococci cause staph infections
Streptococcus cause infections such as strep
throat
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Some well known Bacteria
Streptococcus mutans causes tooth decay by
converting sugars to an acid That erodes the tooth
Clostridium botulinum produces a poison causing
food poisoning
Treponema pallidum causes syphilis
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Gram Stain

• Used to group bacteria into 2 groups based on the
  structure of their cell walls
• 1. Gram-positive bacteria appears purple because
  they retain the crystal violet stain
• Are simpler and have more peptidoglycan
• The stain retains purple dye and appear purple

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Gram-negative bacteria

• 2. Gram-negative bacteria appears pink because
  the cell becomes counterstained by the safranin
  red stain
• Gram negative bacteria have cell walls that are
  complex and have small amounts of peptidoglycan
• It takes up the the red dye of the Gram stain
  making it look pink

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Peptidoglycan
Cell Wall
Peptidoglycan
Cell Wall
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Important Bacterial Groups5 major phyla
(actually 12 phyla exist)

• 1. Cyanobacteria
• 2. Spirochetes
• 3. Gram-Positive Bacteria
• 4. Proteobacteria
• 5. Chlamydia

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Important Bacterial Groups5 major phyla
(actually 12 phyla exist)

• 1. Phylum Cyanobacteria
• (blue green bacteria)
• Photosynthestic
• Encased in a jelly like substance-live in
  colonies
• Some are made of chains of cells with special
  enlarged cells called heterocysts (fixes nitrogen
  into ammonia which plants use)

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• Environmental note Anabaena loves phosphates and
  nitrates-undergoes a population bloom
  (eutrophication)-following the bloom many die and
  become decomposed by heterotrophic bacteria which
  consume large amounts of oxygen causing fish kills

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Important Bacterial Groups5 major phyla
(actually 12 phyla exist)

• 2. Phylum Spirochetes
• Gram negative, spiral-shaped bacteria
• Some are aerobic, some anaerobic
• Moves by means of a cork-screw like rotation
• Live freely, symbiotically, or as parasites
• Treponema pallidum causes syphilis
• Borrelia burgdorferi causes limes disease

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Important Bacterial Groups5 major phyla
(actually 12 phyla exist)

• 3. Phylum Gram Positive Bacteria
• Not all are gram positive
• Some gram negative in this group share molecular
  similarities
• Makes yogurt
• Found in oral cavity and human intestines
• Causes tooth decay
• Makes antibiotics (actinomycetes)

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• Members include
• streptococcal species, causes strep throat
• Clostridium botulinum makes toxins in botulism
  (used medically to treat painful muscle spasms
  and frown lines on the face)
• Anthrax is caused by the rod Bacillus anthracis
  which is used as a biological weapon

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Important Bacterial Groups5 major phyla
(actually 12 phyla exist)

• 4. Phylum Proteobacteria
• Largest most diverse bacteria
• Divided into several subdivisions
• A. Enteric Bacteria
• Gram negative, heterotrophic, found in animal
  intestinal tracts, aerobic or anaerobic,
  Escherichia coli (E.coli) found in human
  intestines makes vitamin K, aids in the break
  down of nutrients, Salmonella-disease causing
  protobacteria

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• B. Chemoautotrophs
• Gram negative, extracts energy from minerals
• Lives symbiotically
• Rhizobium and Azotobacter-fix nitrogen in the
  soil. Live in nodules inside the roots of legumes
  which is important to the success of plants
• Called Nitrogen Fixation
• C. Other Proteobacteria
• Some cause disease like Rocky Mountain Spotted
  Fever
• Helicobacter plyori causes stomach ulcers
• Agrobacterium causes tumors in plants

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Important Bacterial Groups5 major phyla
(actually 12 phyla exist)

• 5. Chlamydia
• Gram-negative-coccoid bacteria
• Live only inside animal cells (rely for
  protection and nutrients)
• The cell walls do not have peptidoglycan
• Chlamydia tramchomatis causes chlamydia---an STD

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The importance of bacteria

• Soybeans have nodules on their roots that convert
  nitrogen gas to ammonia that is used by the plant

• Foods Medicines some foods would not exist
  without bacteria

Swiss cheese
Crispy Pickles
vinegar
sauerkraut
Distinctive flavors
Nitrogen fixing bacteria
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Biology of Prokaryotes
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Structure Function
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Nutrition Metabolism
 
Prokaryotes have many ways of getting carbon and
energy from the environment
Heterotroph
Photoheterotroph Uses light energy but gets its carbon from other organisms
Chemoheterotroph Obtains both energy and carbon from other organisms
Autotrophs
Photoautotroph Uses light energy and gets carbon from CO2
Chemoautotroph Extracts energy from inorganic compounds and uses CO2 as a carbon source
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Reproduction binary fission

• Prokaryotes reproduce asexually by binary fission

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ANTIBIOTICS

• Antibiotics affect bacteria with certain cellular
  activities
• Penicillin blocks the ability to build new cell
  wall material
• Tetracycline blocks protein synthesis
• Antibiotics are made naturally by some fungi
  bacteria
• They kill neighboring bacteria or fungi that
  compete for resources

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Antibiotic Resistance

• A big worry for modern medicine
• Bacteria may become resistant to antibiotics by
• Mutations in bacterial DNA give bacterium
  resistance
• Mutant bacteria multiply take over the
  population and stop the antibiotics curing power

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Viruses

• In 2003, some people in China started showing
  symptoms of a new illness. These symptoms were
  similar to those of pneumonia. The condition was
  highly infectious. Soon, scientists found that
  the disease was caused by a virus. They called
  the disease severe acute respiratory syndrome, or
  SARS

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What is a Virus?

• Youve probably had the fluinfluenzaat some
  time during your life.
• Nonliving particles called viruses cause
  influenza.

• Viruses are composed of nucleic acids enclosed in
  a protein coat and are smaller than the smallest
  bacterium
• Viruses are interesting to scientists because
  they cause many diseases and are useful tools for
  genetic research

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Did You Know

• Viruses are not alive because they lack some of
  the key characteristics of living organisms
• 1. They do not have cytoplasm or organelles
• 2. They cannot carry out cellular functions like
  metabolism and homeostasis
• 3. They do not grow as cells do by dividing into
  two
• 4. They cannot reproduce outside a host cell
• 5. They must enter a living cell and use the host
  cells ribosomes, ATP, enzymes, and other
  molecules to reproduce

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Virus Size and Structure

• Viruses are some of the smallest particles that
  are able to cause disease
• They vary in size and shape

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Viral Shapes
The arrangement of proteins give different shapes
to viruses

• Consist of an inner core of nucleic acid
  surrounded by 1 or 2 protein coats or capsid
• The human flu virus may have another layer called
  a viral envelope surrounded by an outer-coat
• Contains DNA RNA but never both

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Shapes
Nucleic acid

• Viral coat is called capsids
• Polyhedral viruses (polio virus) resembles small
  crystals
• Tobacco mosaic viruses-small cylinders
• T-4 looks like a lunar landing module

Capsid
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Shapes

• Some viruses have a bilipid membrane called an
  envelope that surrounds the capsid
• The envelope is formed from the nuclear membrane
  or the cell membrane of the host cell as the
  viral capsid buds from the host cell

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Classification of Viruses

• By whether they have RNA or DNA as their gnome
  and whether their gnome is double stranded or
  linear or circular.
• Based on the nature of the capsid and on the
  presence or absence of an envelope
• ex SARS is a coronavirus. Corona is the Latin
  word for crown the envelope protein looks like
  a crown

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How are they named?

• Poliovirus
• AIDS VIRUS

• Viruses are not given names
• Often named after the disease they cause
• EXAMPLE RABIES VIRUS

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How are they named?

• Code Numbers are used to name several viruses
  infecting the same host
• Example T-1 ? T-7
• 7 viruses that infect the intestinal bacteria
  E.coli (T stands for Type)

• Others are named for the organ or tissue they
  infect
• EXAMPLE ADENOVIRUSES adenoid tissue in the back
  of the throat

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How are they named?

• Bacteriophage is a virus that infects bacteria T-4

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Attachment to a Host

• Before a virus can replicate, it must enter a
  host cell
• virus recognizes and attaches to a host cell when
  one of its proteins interlocks with a molecular
  shape that is the receptor site on the host
  cells plasma membrane.

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Lytic Cycle To Break Down

• 1. Attachment
• 2. Entry once inside the virus destroys the host
  DNA
• 3. Replication it reprograms the cells metabolic
  activity to copy the virus genes

• 4. Assembly nucleic acid coats are assembled
  into new viruses
• 5. Release host cell breaks open new virus
  particles are released

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A. Attachment
B. Entry
C. Replication
E. Lysis and Release
D. Assembly
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Lysogenic Cycle

1. Begins like the Lytic Cycle
2. Instead of destroying the host cell the DNA
   becomes part of the host
3. New DNA does not interfere with normal functions
   of the host cell

• 4. Every time the host cell reproduces, virus is
  reproduced
• 5. Can continue undetected for many years, but
  can pop out at any time then the virus starts
  killing the host cells.

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Where are Viruses found?

• Viruses are found everywhere
• Some have been linked to cancers, animals, in
  plants
• Ex Tobacco mosaic virus

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Tobacco Mosaic Virus

• First plant virus to be identified
• There are more than 400 viruses that infect a
  variety of plants
• Virus can stunt the growth or yield a loss in the
  host plants
• Plant viruses require wounds, or insect bites to
  enter and infect the host

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Tobacco Mosaic Virus
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Some Other Well known Viruses
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Small Pox

• 30 of infected die
• Vaccines not administered to public since 1970s
• No treatment, only preventative vaccine
• Used as a biological weapon

The last case of smallpox in the United States
was in 1949
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Hepatitis

• Is an inflammation of the liver
• Can be caused by 5 different viruses
• Hepatitis A E can be spread by fecal
  contaminated food and water
• Hepatitis B, C, D are spread by sexual contact,
  by contact with infected blood an serum, and by
  the use of contaminated needles
• Symptoms fever, nausea, jaundice, and liver
  failure

Caused by Hepatitis B
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Influenza A, B, C

• Influenza types A or B viruses cause epidemics of
  disease almost every winter.
• In the U.S. influenza epidemics can cause illness
  in 10 to 20 of people average 36,000 deaths and
  114,000 hospitalizations per year

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Influenza Pandemic of 1918

• http//www.youtube.com/watch?vrbYwNOcKqqcfeature
  channel

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AIDS Virus

• HIV is the virus that causes AIDS.
• AIDS is a serious condition in which the body's
  defenses against some illnesses are broken down.

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Herpes Virus

• The virus Herpes simplex causes the common
  sexually transmitted disease genital herpes
• There are two types of Herpes Simplex, and both
  can cause genital herpes

Most babies are born through c-section
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HPV

• Genital Wartsone of the most common types of
  sexually transmitted diseases
• Virus that causes them called the human
  papillomavirus
• http//www.thesahara.net/verrucas_plantar_warts.ht
  m

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Bubonic Plague

• During the 1300s - a massive epidemic swept
  through Europe, killing one-third of the
  population by some estimates, and subsequently
  changing the course of European history.
• Referred to as The Black Death, Caused from being
  bitten by a rodent flea that is infected with the
  disease

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Polio Virus

• Phase 3 Muscle weakness and muscle paralysis,
  difficult swallowing, nasal voice, difficulty
  breathing

• It enters through the mouth is contagious.
• Phase 1 Fever, headache, sore throat, spewing,
  malaise(general bodily weakness and discomfort).
• Phase 2 Meningitis, fever, severe headaches,
  stiff neck and back, muscle pain.

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SARS

• When first introduced into the United States,
  SARS was thought to be a chemical weapon.

• Originated in Asia in 2003
• Stands for Acute Respiratory Syndrome and can be
  contracted by close person to person contact.

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West Nile Virus

• Virus carried by mosquitoes causing EEE.
• The most serious outbreak causes inflammation of
  the brain in humans and horses, as well as
  mortality in certain domestic and wild birds

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Ebola Virus

• Ebola Virus, common name for several strains of
  virus, three of which are known to cause
  hemorrhagic fever in humans, which is
  characterized by massive bleeding and destruction
  of internal tissues.

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Chicken Pox

• Chicken pox is a rash illness caused by a virus.
• Chicken pox usually occurs in childhood. More
  than 90 of Chicken pox cases occur in children
  less than 12 years of age.

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Shingles

• Chicken pox and shingles are caused by the same
  varicella-zoster herpesvirus
• The virus multiplies in the lungs and travels to
  blood vessels in the skin

The painful shingles rash, caused By a herpes
virus, is limited to an Area of the skin
innervated by a Particular nerve branch Ex on
the side of the chest
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Anthrax
Caused by the bacteria Bacilli

• Anthrax most commonly found in wild domestic
  lower animals (cattle, sheep, goats, camels,
  antelopes
• They ingest spores from soil
• It can occur in humans when they are exposed to
  infected animals
• Or when anthrax spores are used as a
  bio-terrorist weapon

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Yellow Fever

• Yellow fever is a serious viral infection,
  transmitted by mosquitoes in tropical regions
• There are no medicines that are effective against
  this virus

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Emerging Viral Diseases

• Are illnesses caused by new or reappearing
  infectious agents that typically exist in animal
  populationoften in isolated habitatsand can
  infect humans who interact with these animals.
• Ex Ebola virus also called hemorrhagic fever