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BACTERIA 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 11 The red color of this snow is due to a blue-green bacteria Kingdom Eubacteria • Can have one of three basic shapes 1. Bacilli – rod-shaped 2. Spirilla – spiral-shaped 3. Cocci – sphere-shaped Streptococci – in chains Staphylococci – grape-like clusters 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. 25 No Nucleus-DNA in Cytoplasm 26 Nutrition and Growth • • • • 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 27 – Some are Thermophilic, Some prefer acidic envmt. These heterotrophic bacteria digest oil -remember oil is partially decayed plant and animal cells 28 REPRODUCTION IN BACTERIA (please add to notes) 29 No Nucleus-DNA in Cytoplasm 30 BACTERIA REPRODUCES BY FISSION First the chromosomal DNA makes a copy The DNA replicates 31 NEXT THE CYTOPLASM AND CELL DIVIDES The two resulting cells are exactly the same 32 In addition to the large chromosomal DNA, bacteria have many small loops of DNA called Plasmids 33 Genetic Recombination Characteristic Transformation Conjugation Transduction Method of DNA Across cell Transfer wall and cell membrane of recipient Through a conjugation bridge between two cells By a virus Plasmid transfer Yes Yes Not likely Chromosome transfer No Sometimes No Antibiotic resistance acquired Yes Yes Sometimes 34 TRANSFORMATION This plasmid of DNA is new to the bacteria – added by transformation! Produces the glowing protein 35 CONJUGATION 36 TRANSDUCTION 37 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, Sneezes, coughs, skin etc. Tetanus Costridium tetani Nerves Contaminated 38 wounds Some bacteria cause diseases -Disease causing bacteria are call PATHOGENIC 39 Helicobacter pylori is the pathogenic bacteria that can causes ulcers 40 Leprosy is a bacterial infection that decreases blood flow to the extremities resulting in the deterioration of toes, ears, the nose and the fingers. 41 BOTULISM 42 CHOLERA 43 DENTAL CARIES 44 ROCKY MOUNTAIN SF 45 LYME DISEASE 46 SALMONELLA 47 STREP THROAT 48 TUBERCULOSIS 49 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 50 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. 51 VIRUSES Non-living but depends on the living! 52 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.. 53 54 Here is a non-enveloped bacteria virus inserting it’s DNA into a bacterial cell. 55 Some virus are pushed out by the cell, taking some of the cell membrane with them. 56 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 57 All viruses have two main parts: 1. DNA or RNA – genetic info 2. Capsid – a protein encasement 58 • 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 59 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 60 PRIONS – man-made problem? 61 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. 62 63 Viral Replication Picture http://www.mcgrawhill.ca/school/schoolGraphics/biology2_1.mpg Click Movie to Play 64 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 65 66 Here is a classic picture of HIV viral progeny being released from the surface of a T- cell. Notice the membrane coating they receive. 67 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. 68 69 70 71 72 PAPOVAVIRUSES BACK 73 ADENOVIRUSES BACK 74 HERPESVIRUSES BACK 75 POXVIRUSES BACK 76 PICORNAVIRUSES BACK 77 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. 78 Which US President had polio? 79 80 81 MYXOVIRUSES BACK 82 RHABDOVIRUSES BACK 83 RETROVIRUSES BACK 84 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 85 (binary fission) 86 • Bacteria have plasmids – extra DNA in the form of a circle 87 • 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 88 • So… why not take out a plasmid, cut it apart and add any other DNA piece that we want! 89 • Then put it back in the bacteria and grow more bacteria with that new plasmid that http://www.learner.org/channel/courses/biology/archive/ani wemations.html have created! Hmmm? 90 • How could rDNA and transformation be useful? • To be answered in DNA technology presentations 91 • Transduction – viruses attack cells • Bacteriophages: like tiny little syringes that inject DNA into the cell 92 Look at how the virus infects http://www.slic2.wsu.edu:82/hurlbert/micro10 1/pages/Chap11.html 93 Viral Infections • Ebola 94 • How could scientists use viruses for DNA technology • To be answered in DNA technology presentations 95 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 96 to chapter 13