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BACTERIA EW! They are everywhere!
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Bacteria are very small
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This is a pore in human skin and the yellow spheres are bacteria
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Bacteria are very small compar-ed to cells with nuclei
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Bacteria compared to a white blood cell that is going to eat it
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Clean skin has about 20 million bacteria per square inch
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Evolution/Classification
Most numerous on Earth Most Ancient Microscopic Prokaryotes Evolution has yielded many species adapted to survive where no other organisms can. Grouped based on: Structure, physiology, molec. Composition reaction to specific types of stain. Eubacteria= Germs/bacteria Archaebacteria
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Kingdom Archaebacteria
First discovered in extreme environments Methanogens: Harvest energy by converting H2 and CO2 into methane gas Anaerobic, live in intestinal tracts Extreme halophiles: Salt loving, live in Great Salt Lake, and Dead sea. Thermoacidophiles: Live in acid environments and high temps. Hot Springs, volcanic vents
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Volcanic vents on the sea floor
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Chemosynthetic bacteria use the sulfur in the “smoke” for energy to make ATP.
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The red color of this snow is due to a blue-green bacteria
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Kingdom Eubacteria Bacilli – rod-shaped Spirilla – spiral-shaped
Can have one of three basic shapes Bacilli – rod-shaped Spirilla – spiral-shaped Cocci – sphere-shaped Staphylococci – grape-like clusters Streptococci – in chains SHOW ME
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BACTERIA PICS
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Bacillus bacteria are rod or sausage shaped
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Coccus bacteria are sphere or ball shaped
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Spirillium bacteria have a corkscrew shape
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Diplo-bacteria occur in pairs, such as the diplococcus bacteria that causes gonorrhea
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Staphylo - bacteria occur in clumps, such as this staphylococcus bacteria that causes common infections of cuts
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Strepto- bacteria occur in chains of bacteria, such as this streptococcus bacteria that causes some types of sore throats
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Spirillium bacteria
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Diplobacillus bacteria
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Streptococcus bacteria
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Staphylococcus bacteria
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The red and yellow dots are bacteria
The tip of a needle The red and yellow dots are bacteria
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Gram Stain Gram-positive retain stain and appear purple
Have thicker layer in cell wall. Gram-negative do not retain stain and take second pink stain instead. Phylum Shape Motility Metabolism Gram reacion Cyanobacteria Bacilli, Cocci Gliding, some non-motile Aerobic, photosynthetic autotrophic Gram-negative Spirochetes Spirals Corkscrew Aerobic, and anaerobic; heterotrophic Gram-Pos Bacilli, cocci Flagella; some non-motile Aer/anaer.; heterotrophic, photosynthetic Mostly gram-positive Proteobacteria Bacilli, cocci, spiral Aer/anaer.; heterotrophic, photosynthetic autotrophic
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STRUCTURE OF BACTERIA Structure Function Cell Wall
Protects and gives shape Outer Membrane Protects against antibodies (Gram Neg. Only) Cell Membrane Regulates movement of materials, contains enzymes important to cellular respiration Cytoplasm Contains DNA, ribosomes, essential compounds Chromo-some Carries genetic information Plasmid Contains some genes obtained through recomb. Capsule & Slime Layer Protects the cell and assist in attaching cell to other surfaces Endospore Protects cell agains harsh enviornments Pilus Assists the cell in attaching to other surfaces Flagellum Moves the cell
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No Nucleus-DNA in Cytoplasm
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Nutrition and Growth Temperature requirements
Heterotrophic or Autotrophic Some are Photoautotrophs – Use sunlight for Energy Some are Chemoautotrophs. Many are Obligate Anaerobes. Oxygen = Death Ex. Clostridium tetani – Tetanus Some are Faculatative Anaerobes With or without Oxygen Ex. Escherichia Coli Some are Obligate Aerobes Ex.) Mycobacterium tuberculosis Temperature requirements Some are Thermophilic, Some prefer acidic envmt.
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These heterotrophic bacteria digest oil -- remember oil is partially decayed plant and animal cells
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REPRODUCTION IN BACTERIA
(please add to notes)
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No Nucleus-DNA in Cytoplasm
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BACTERIA REPRODUCES BY FISSION First the chromosomal DNA makes a copy
The DNA replicates
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The two resulting cells are exactly the same
NEXT THE CYTOPLASM AND CELL DIVIDES The two resulting cells are exactly the same
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In addition to the large chromosomal DNA, bacteria have many small loops of DNA called Plasmids
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Genetic Recombination
Nonreproductive Methods bacteria can acquire new genetic material. Characteristic Transformation Conjugation Transduction Method of DNA Transfer Across cell wall and cell membrane of recepient Through a conjugation bridge between two cells By a virus Plasmid transfer Yes Not likely Chromosome transfer No Sometimes Antibiotic resistance acquired
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TRANSFORMATION This plasmid of DNA is new to the bacteria – added by transformation! Produces the glowing protein
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CONJUGATION
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TRANSDUCTION
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Bacteria and Disease Disease Pathogen Areas affected
Mode 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 Salmonella Contaminated food, water Strep throat Streptococcus pyogenes URT, blood, skin Sneezes, coughs, etc. Tetanus Costridium tetani Contaminated wounds Tuberculosis Mycobacterium tuberculosis Lung, bones coughs
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Some bacteria cause diseases --Disease causing bacteria are call
PATHOGENIC
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Helicobacter pylori is the pathogenic bacteria that can causes ulcers
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Leprosy 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
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CHOLERA
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DENTAL CARIES
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ROCKY MOUNTAIN SF
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LYME DISEASE
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SALMONELLA
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STREP THROAT
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TETANUS
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TUBERCULOSIS
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Common Antibiotics Antibiotic Mechanism Target bacteria Penicillin
Inhibits cell wall synthesis Gram Positive Ampicillin Broad spectrum Bacitracin Gram Positive – Skin Ointment Cephalosporin Tetracycline Inhibits Protein Synthesis Streptomycin Gram Neg. tuberculosis Sulfa drug Inhibits cell metabolism Bacterial meningitis, UTI Rifampin Inhibits RNA synthesis Gram Pos., some Neg. Quinolines Inhibits DNA Synthesis UTI
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Some Final Information
Because antibiotics have been overused, many diseases that were once easy to treat are becoming more difficult to treat. Some Bacteria are Useful Ex.) Producing and Processing food Breaking down dead organic material Make unripened cheese like ricotta and cottage by breaking down the protein in milk.
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Non-living but depends on the living!
VIRUSES Non-living but depends on the living!
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STRUCTURE Nonliving Composed of Nucleic acid and protein
Cause many diseases Virology – Study of Viruses Comparison of Viruses and Cells below Char. Of Life Virus Cell Growth No Yes Homeostasis Metabolism Mutation Nucleic acid DNA or RNA DNA Reproduction Only within host cell Independently by cell division Structure Nucleic acid core, protein covering, some have envelope Cytoplasm, cell membrane, etc..
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Here is a non-enveloped bacteria virus inserting it’s DNA into a bacterial cell.
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Some virus are pushed out by the cell, taking some of the cell membrane with them.
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Characteristics of Viruses
2 essential features 1. Nucleic Acid May be DNA or RNA Helical, closed loop, or long strand 2. Protein Coat – called CAPSID Some have ENVELOPE Ex. Influenza, chickepox, herpes simplex, HIV VIRAL SHAPE Icosahedron – 20 triangular faces Ex.) herpes, chickenpox, polio Helix – Coiled spring EX.)Rabies, measles, tobacco mosaic
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All viruses have two main parts:
DNA or RNA – genetic info Capsid – a protein encasement
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Grouping Viruses Grouped according to:
Presence of Capsid and envelope – shape RNA or DNA, single or double stranded – struct. Viral Group Nucleic Acid Shape and Structure Example Papovaviruses DNA Icosahedral, non-env. Warts, cancer Adenoviruses Resp. & intestinal infections Herpesviruses Icosahedral, enveloped Herpes simplex, chicken pox, mono, shingles Poxviruses Complex brick, enveloped Small pox, cow pox Picornaviruses RNA Polio, hepatitis, cancer Myxoviruses Helical, enveloped Influenza A, B, C Rhabdoviruses Rabies Retroviruses AIDS, cancer
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Grouping Viruses Viroids- The smallest known particle that can replicate. Disrupt plant cell metabolism Can destroy entire crops Prions – Abnormal forms of proteins that clump together inside cells. Clumping eventually kills the cell Examples Scrapie – in sheep Mad Cow Disease
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PRIONS – man-made problem?
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Viral Replication Can replicate only by invading host cell and using its enzyme and organelles. Bacteriophage – viruses that infect bacteria Used to study viruses Lytic Cycle Viral genome is released into the host cell Replication follows immediately Cellular components used to make new viruses Viral enzyme kills cell.
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Viral Replication Picture
Click Movie to Play
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Replication cont’ Lysogenic Cycle
Nucleic acid of virus becomes part of the host cell’s chromosome Nucleic acid remains in the cell in this form for many generations HIV follows this pattern HIV infects WBC and remains as proviruses As immune system fails, opportunistic infections occur = AIDS
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Here is a classic picture of HIV viral progeny being released from the surface of a T- cell. Notice the membrane coating they receive.
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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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PAPOVAVIRUSES BACK
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ADENOVIRUSES BACK
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HERPESVIRUSES BACK
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POXVIRUSES BACK
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PICORNAVIRUSES Polio BACK
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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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MYXOVIRUSES BACK
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RHABDOVIRUSES BACK
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RETROVIRUSES AIDS BACK
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What does bacteria have to do with DNA technology?
Bacteria are simple Bacteria have DNA that is made of nucleotides (A,T,G,C) Bacteria can be grown quickly and easily Give them food, warmth and dark (like inside you shoe) and they will multiply like mad (binary fission)
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Bacteria have plasmids – extra DNA in the form of a circle
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Plasmids are DNA – made out of A,T,C,G nucleotides
The same nucleotides found in human DNA, plant DNA, dog DNA, fish DNA, fungus DNA Get it – it’s all the same molecule
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So… why not take out a plasmid, cut it apart and add any other DNA piece that we want!
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Then put it back in the bacteria and grow more bacteria with that new plasmid that we have created! Hmmm?
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How could rDNA and transformation be useful?
To be answered in DNA technology presentations
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Transduction – viruses attack cells
Bacteriophages: like tiny little syringes that inject DNA into the cell
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Look at how the virus infects
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Viral Infections Ebola
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How could scientists use viruses for DNA technology
To be answered in DNA technology presentations
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Time to take ownership Here’s what you should have down by the end of the class Wednesday: Bacteria and virus structures Types of bacteria Types of viruses How bacteria and viruses cause infection How bacteria and viruses can be useful DNA technology tools Overview of various DNA technologies – refer to chapter 13
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