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BACTERIA Biology Chapter 24 1 Bacteria are very small 2 This is a pore in human skin and the yellow spheres are bacteria 3 Bacteria are very small compared to cells with nuclei 4 Bacteria Bacteria compared to a white blood cell that is going to eat it 5 Clean skin has about 20 million bacteria per square inch 6 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 7 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 8 Volcanic vents on the sea floor 9 Chemosynthetic bacteria use the sulfur in the “smoke” for energy to make ATP. 10 The red color of this snow is due to a blue-green bacteria 11 Kingdom Eubacteria Can have one of three basic shapes 1. Bacilli – rod-shaped 2. Spirilla – spiral-shaped 3. Cocci – sphere-shaped Staphylococci – grape-like clusters Streptococci – in chains SHOW ME 12 BACTERIA PICS 13 Bacillus bacteria are rod or sausage shaped 14 Coccus bacteria are sphere or ball shaped 15 Spirillium bacteria have a corkscrew shape 16 Diplo-bacteria occur in pairs, such as the diplococcus bacteria that causes gonorrhea 17 Staphylo bacteria occur in clumps, such as this staphylococcus bacteria that causes common infections of cuts 18 Streptobacteria occur in chains of bacteria, such as this streptococcus bacteria that causes some types of sore throats 19 Spirillium bacteria 20 Diplobacillus bacteria 21 Streptococcus bacteria 22 Staphylococcus bacteria 23 The tip of a needle The red and yellow dots are bacteria 24 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 nonmotile Aerobic, Gramphotosynthetic negative autotrophic Spirochetes Spirals Corkscrew Aerobic, and anaerobic; heterotrophic Gram-Pos Bacilli, cocci Flagella; some nonmotile Aer/anaer.; Mostly heterotrophic, gramphotosynthetic positive Proteobacteria Bacilli, cocci, spiral Flagella; some nonmotile Aer/anaer.; heterotrophic, photosynthetic autotrophic Gramnegative Gramnegative 25 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 Chromosome Carries genetic information Plasmid Contains some genes obtained through recomb. Capsule & Protects the cell and assist in attaching cell to Slime Layer other surfaces Endospore Protects cell agains harsh enviornments Pilus Assists the cell in attaching to other surfaces Flagellum Moves the cell 26 No Nucleus-DNA in Cytoplasm 27 Nutrition and Growth Heterotrophic or Autotrophic Some are Photoautotrophs – Use sunlight for Energy Some are Chemoautotrophs. Many are Obligate Anaerobes. Oxygen = Death Ex. Some are Faculatative Anaerobes With or without Oxygen Ex. Clostridium tetani – Tetanus Escherichia Coli Some are Obligate Aerobes Ex.) Mycobacterium tuberculosis Temperature requirements Some are Thermophilic, Some prefer acidic envmt. 28 These heterotrophic bacteria digest oil -remember oil is partially decayed plant and animal cells 29 REPRODUCTION IN BACTERIA (please add to notes) 30 No Nucleus-DNA in Cytoplasm 31 BACTERIA REPRODUCES BY FISSION First the chromosomal DNA makes a copy The DNA replicates 32 NEXT THE CYTOPLASM AND CELL DIVIDES The two resulting cells are exactly the same 33 In addition to the large chromosomal DNA, bacteria have many small loops of DNA called Plasmids 34 Genetic Recombination Nonreproductive Methods bacteria can acquire new genetic material. Characteristic Transformation Conjugation Transduction Method of DNA Across cell wall Transfer and cell membrane of recepient Through a By a virus conjugation bridge between two cells Plasmid transfer Yes Yes Not likely Chromosome transfer No Sometimes No Antibiotic resistance acquired Yes Yes Sometimes 35 TRANSFORMATION This plasmid of DNA is new to the bacteria – added by transformation! Produces the glowing protein 36 CONJUGATION 37 TRANSDUCTION 38 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 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 39 Some bacteria cause diseases -Disease causing bacteria are call PATHOGENIC 40 Helicobacter pylori is the pathogenic bacteria that can causes ulcers 41 Leprosy is a bacterial infection that decreases blood flow to the extremities resulting in the deterioration of toes, ears, the nose and the fingers. 42 BOTULISM 43 CHOLERA 44 DENTAL CARIES 45 ROCKY MOUNTAIN SF 46 LYME DISEASE 47 SALMONELLA 48 STREP THROAT 49 TETANUS 50 TUBERCULOSIS 51 Common Antibiotics Antibiotic 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 52 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. 53 VIRUSES Non-living but depends on the living! 54 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 No Yes Metabolism No Yes Mutation Yes Yes 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.. 55 56 Here is a non-enveloped bacteria virus inserting it’s DNA into a bacterial cell. 57 Some virus are pushed out by the cell, taking some of the cell membrane with them. 58 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 59 All viruses have two main parts: 1. DNA or RNA – genetic info 2. Capsid – a protein encasement 60 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 DNA Icosahedral, non-env. Resp. & intestinal infections Herpesviruses DNA Icosahedral, enveloped Herpes simplex, chicken pox, mono, shingles Poxviruses DNA Complex brick, enveloped Small pox, cow pox Picornaviruses RNA Icosahedral, non-env. Polio, hepatitis, cancer Myxoviruses RNA Helical, enveloped Influenza A, B, C Rhabdoviruses RNA Helical, enveloped Rabies Retroviruses RNA Icosahedral, enveloped AIDS, cancer 61 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 62 PRIONS – man-made problem? 63 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. 64 65 Viral Replication Picture http://www.mcgrawhill.ca/school/schoolGraphics/biology2_1.mpg Click Movie to Play 66 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 67 68 Here is a classic picture of HIV viral progeny being released from the surface of a T- cell. Notice the membrane coating they receive. 69 Viruses and Human Disease Control and Prevention of spread. Vaccination & Antiviral drugs Emerging Viruses – exist in isolated habitats Ex.) chickenpox vaccine, AZT, Acyclovir, protease inhibitors. 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. 70 71 72 73 74 PAPOVAVIRUSES BACK 75 ADENOVIRUSES BACK 76 HERPESVIRUSES BACK 77 POXVIRUSES BACK 78 PICORNAVIRUSES BACK 79 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. 80 Which US President had polio? 81 82 83 MYXOVIRUSES BACK 84 RHABDOVIRUSES BACK 85 RETROVIRUSES BACK 86 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) 87 88 Bacteria have plasmids – extra DNA in the form of a circle 89 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 90 So… why not take out a plasmid, cut it apart and add any other DNA piece that we want! 91 Then put it back in the bacteria and grow more bacteria with that new plasmid that we have created! Hmmm? http://www.learner.org/channel/courses/biology/archive/ani mations.html 92 How could rDNA and transformation be useful? To be answered in DNA technology presentations 93 Transduction – viruses attack cells Bacteriophages: like tiny little syringes that inject DNA into the cell 94 Look at how the virus infects http://www.slic2.wsu.edu:82/hurlbert/mic ro101/pages/Chap11.html 95 Viral Infections Ebola 96 How could scientists use viruses for DNA technology To be answered in DNA technology presentations 97 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 98