* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Viruses & Bacteria
Survey
Document related concepts
Cell culture wikipedia , lookup
Genetic engineering wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell theory wikipedia , lookup
Dictyostelium discoideum wikipedia , lookup
Developmental biology wikipedia , lookup
Germ theory of disease wikipedia , lookup
Cell (biology) wikipedia , lookup
Neurodegeneration wikipedia , lookup
Microbial cooperation wikipedia , lookup
List of types of proteins wikipedia , lookup
Antiviral drug wikipedia , lookup
Transcript
Viruses & Bacteria Chapter 19 Pages 471 - 490 Compare/Contrast Prokaryotes (Bacteria) Eukaryotes Smaller Simpler Has genetic material No nucleus Grow, reproduce, & respond to environment Some move by gliding or swimming Some have internal membranes Unicellular Larger Complex Has genetic material Nucleus Grow, reproduce, & respond to environment All move Have internal membranes Unicellular & multicellular Has organelles & cytoplasm Pathogen – disease causing organisms • Virus • Bacteria • Fungi • Protozoans Bacteria • Prokaryotes –Smallest, most common microorganism –Single-celled –Lack nucleus –Has DNA Bacteria • 2 Kingdoms • Archaebacteria – Look similar. – Live in harsh environments. – Lack peptidoglycan in the cell wall. – Have different membrane lipids. – DNA sequences of key genes are more like those of eukaryotes than eubacteria. – Are thought to be ancestors of eukaryotes. – Ex. Methangones- produce methane gas. Bacteria • 2 Kingdoms • Eubacteria (pg. 472) – live almost everywhere, larger of the two. – Usually surrounded by a cell wall made up of carbohydrate & peptidoglycan. – Cell membrane inside cell wall. – Cytoplasm. – Ex. E coli Bacteria • How we Identify Prokaryotes (cont.): – How they release energy by cellular respiration and fermentation • Obligate aerobes – require constant supply of oxygen. Ex. Tuberculosis. • Obligate anaerobes – do not require oxygen. Oxygen could kill it. Ex. Botulism is found in canned food that’s not properly sterilized. • Facultative anaerobes – can survive with or without oxygen. Can live anywhere. Ex. E coli which is found in the large intestines or in sewage or contaminated water. Bacteria contain: •one circular piece of DNA •tiny circular pieces of DNA called plasmids •ribosomes Bacteria have cell walls made of: •peptidoglycan (a sugar linked to chains of amino acids). •this may be covered with an outer membrane of lipopolysaccharide (chain of sugar with a fat attached). Some bacteria: • have a gelatinous layer called a capsule surrounding the cell wall. • form thick-walled endospores around chromosomes when they are exposed to harsh conditions (drought, high temperatures) these types cause botulism Some bacteria have: • flagella for locomotion. • pili (short, thicker outgrowths that help cell to attach to surfaces) Cell Morphology • Bacteria vary widely in size. • There are three basic shapes: – Round or spherical: cocci (coccus) – Rod-shaped: bacilli (bacillus) – Curved or spiral shaped: spirilla Cell Morphology • There are different arrangements: – Pairs of spheres: diplococci – Chains of spheres: streptococci – Clusters of spheres: staphylococci Gram Reactions • Bacteria can be classified into two categories based on their reaction to a Gram stain – Gram + stain purple. – Gram – stain pink to red. • This color difference is due to the thickness of cell wall. – Gram + are thick – Gram – are thin Bacteria • How we Identify Prokaryotes: • Shape – bacilli, cocci, spirilla. • By the way they move. • By the way they obtain energy. – Most are Heterotrophes which obtain energy by consuming food. » Chemoheterotroph- Ex. Botulism (food poisoning). » Photoheterotroph- uses photosynthesis. – Autotrophs make their own food. » Chemoautotroph- found in deep ocean floors. » Photoautotroph- found near surface in lakes oceans & streams. • The chemical nature of their cell walls. – A method of Gram Staining is used to determine nature. Gram (+) = violet, Gram (-) = pink. Bacteria • How we Identify Prokaryotes: • Shape – bacilli, cocci, spirilla. • By the way they move. • By the way they obtain energy. – Most are Heterotrophes which obtain energy by consuming food. » Chemoheterotroph- Ex. Botulism (food poisoning). » Photoheterotroph- uses photosynthesis. – Autotrophs make their own food. » Chemoautotroph- found in deep ocean floors. » Photoautotroph- found near surface in lakes oceans & streams. • The chemical nature of their cell walls. – A method of Gram Staining is used to determine nature. Gram (+) = violet, Gram (-) = pink. Bacteria • Reproduction – Binary fission – DNA replicates & divides producing 2 daughter cells. Asexual reproduction. – Conjugation – process where genetic information is exchanged. – Spore formation – an endospore may form when growth conditions become unfavorable. Bacteria reproduce: asexually using binary fission. Bacteria reproduce: sexually using conjugation. Bacteria exchange plasmid DNA. This is how bacteria become antibiotic resistant. There are three types of bacteria based on how they obtain energy: heterotrophs, photosynthetic, and chemoautotrophs. This is the anthrax bacterium. 1.Most are heterotrophs: a. Decomposers – feed on and recycle organic material b. Pathogens – parasitic, disease-causing bacteria • Either attack cells or secrete toxins c. Nitrogen-fixing bacteria (Rhizobium) • Found in nodules of soybeans, peanuts, alfalfa, and clover • Convert atmospheric nitrogen (N2) into ammonia, called nitrogen fixation. • Used in crop rotation Nitrogen fixing bacteria in the nodules of roots 2. Some are photosynthetic. •These are autotrophs that use the sun’s energy to make food. 3. Chemoautotrophs •Obtain energy from molecules like ammonia and methane to make food. •Examples: Nitrobacter and Nitrosomonas - live in soil - have a crucial role in nitrification (turn ammonia into nitrates, the form of nitrogen commonly used by plants). Bacteria produce disease in 2 ways: • Bacteria damage the cells & tissues of the infected organism directly by breaking down the cells for food. • Bacteria release toxins (poisons) that travel throughout the body interfering with the normal activity of the host. A Summary of Bacterial Diseases Disease Pathogen Area affected Mode of transmission Botulism Closridium botulinum Nerves Improperly preserved foods Cholera Vibrio cholerae Intestine Contaminated water Dental caries (tooth decay) Streptococcus mutans, sanguis and salivarius Teeth bacteria enter the mouth from the environment Gonorrhea Neisseria gonorrhoeae Urethra, fallopian tubes, epididymis Person to personby sexual contact Lyme disease Borrelia burgdorferi Skin, joints, heart Tick bite A Summary of Bacterial Diseases Disease Pathogen Area affected Mode of transmission Rocky mountain spotted fever Rickettsia ricketsii Blood, skin Tick bite Salmonella food poisoning Salmonella Intestine Contaminated water and food Strep throat Streptococcus pyogenes Upper respiratory tract, blood, skin Person to person by sneezes, coughs or direct contact Tetanus Clostridium tetani Nerves at synapses Contaminated wounds Tuberculosis Mycobacterium tuberculosis Lung, bones, other organs Person to person by coughs • work by preventing cell wall formation, breaking up cell membranes, or disrupting chemical processes. •cannot treat viral infections. A Summary of common Antibiotics Antibiotic or synthetic drug Mechanism of action Target bacteria Penicillin Inhibits cell-wall synthesis Gram-positive bacteria Ampicillin Inhibits cell-wall synthesis Broad spectrum Bacitracin Inhibits cell-wall synthesis Gram-positive bacteria; used as skin-ointment Tetracycline Inhibits protein synthesis Broad spectrum Streptomycin Inhibits protein synthesis Gram-negative bacteia, tuberculosis Sulfa drug inhibits cell metabolism Bactrial meningitis, urinary tract infections Rifampin Inhibits RNA synthesis Gram-positive bacteria and some Gram negative bacteria Quinolines Inhibits DNA synthesis Urinary-tract infections Strep throa Streptococcus Staphylococcus Gonorrhea-Passed from Mother to Baby Syphilis Helpful Bacteria • Decomposers break down dead organic material • Biotechnology - inserting helpful genes into a plasmid • Bioremediation - bacteria eat up oil spills • Food production – cheese and yogurt • Put nitrogen back into the soil • Aid in digestion Interdependence VIDEO CLIP Viruses and organisms rely on their environment and other species for survival. Little Assassins: What are Virus http://app.discoveryeducation.com/search?Ntt=little+assassins+wh at+are+viruses Viruses • Must infect living cells in order to reproduce. • Are Parasites. • Are not considered to be living things because they are not made up of cells & cannot live independently. • See Chart on pg. 483 Viruses Viruses are NOT cells. A virus is an infectious agent made up of: •a core of nucleic acid (RNA or DNA) •a protein coat Alive or not? Even scientists disagree as to whether or not viruses are alive. What do you think? Look at the chart on the next page to help you decide. Study of Viruses http://app.discoveryeducation.com/search? Ntt=The+electron+microscope+how+viruse s+work Grouping Viruses • Viruses occur in different shapes. Helical and icosahedral are two examples of virus shapes Characteristic of life CELL VIRUS Made of cells YES NO Obtain & use energy YES NO Grow & develop YES Reproduce YES Respond & adapt Contain RNA or DNA Only inside a living cell Only inside a living cell YES YES YES YES Structure of a virus ENVELOPE • Envelope (part of the protein coat) • Capsid (part of the protein coat) • Nucleic acid (either DNA or NUCLEIC RNA) ACID CAPSID How viruses work • http://app.discoveryeducation.com/search ?Ntt=how+viruses+work 5 Steps of Replication 1. Attachment 2. Injection of genetic material 3. Making new parts 4. Assembly of parts 5. Release of new parts AIMAR Bacteriophage • A virus that only infects bacteria • Ex. Bacteriophage T4 CAPSID HEAD DNA CAPSID TAIL FIBER VIRUSES VIRUSES, CONT. Ticking time bombs . . . Viruses do not reproduce, EXCEPT inside a living cell. They invade a living cell and let the cell do the work for them. Viruses • Once inside a host cell: pg. 481 – Lytic infection • Virus inters cell and makes copies of itself. • Causes cell to burst, releasing new virus particales that can attack other cells. • It then uses materials of host cell to make copies of its own DNA molecule. • Host cell is destroyed. – Lysogenic infection • Virus integrates its DNA into the DNA of host cell. • The viral genetic info. replicates along with the host cell’s DNA. • Viral DNA that’s embedded in host’s DNA is called prophage. • Unlike lytic, it does not lyse the host cell right away so it may remain a part of DNA of host for many generations. Lytic Cycle An infection that kills the host cell rapidly. Virus inters cell and makes copies of itself. Causes cell to burst, releasing new virus particales that can attack other cells. It then uses materials of host cell to make copies of its own DNA molecule. Cycle Illustration 1 2 4 3 5 Lysogenic Cycle A viral infection that integrates its DNA into the DNA of host cell, remains harmless for a period of time (sometimes years), and then becomes harmful later. The viral genetic info. replicates along with the host cell’s DNA. Viral DNA that’s embedded in host’s DNA is called prophage. Unlike lytic, it does not lyse the host cell right away so it may remain a part of DNA of host for many generations. Viral Diseases • Viruses disrupt the body’s normal equilibrium. • Viruses attack & destroy certain body cells causing the symptoms of the disease. • Diseases: – – – – – Common cold Influenza AIDS Chickenpox Measles • Can produce other serious diseases in both animals & plants. • Plant viruses have a difficult time entering cells they infect partly because plant cells have though cell walls. Viral Diseases • 2 Virus like particles can cause disease: • Viroids – single-stranded RNA molecules that have no surrounding capsoid. (cause disease in plants). – Ex. Tobacco mosaic virus. • Prions – particles that contain only protein which have no DNA or RNA. (cause disease in animals & humans). – Ex. Foot & mouth disease in livestock. Viruses Throughout history • http://app.discoveryeducation.com/search ?Ntt=viruses+throughout+history Some Common Viruses of Humans Viral group Nucleic acid Shape and Structure Example of diseases they cause Mode of Transmission/ Effect on Body Papovaviruses DNA Icosahedral, nonenveloped Human papillomavirus (HPV) Mother to child at birth, sexual activity/ Warts, cancer Adenoviruses DNA Icosahedral, nonenveloped Respiratory and intestinal infections Direct contact , inhalation/ colds, bronchitis, fever, sore throat, pink eye… Herpesviruses DNA Icosahedral, enveloped Herpes simplex, chickenpox, shingles, infectious mononucleosis Direct Contact, eat or drink after/ blisters, sore throat, fever, enlarged spleen Poxviruses DNA Complex brickshaped, enveloped Smallpox, cowpox Inhalation/ Lesions, blindness, fever, often fatal Some Common Viruses of Humans Nucleic acid Shape and Structure Example of diseases they cause Mode of Transmission/ Effect on Body Rhinovirus RNA Icosahedral, nonenveloped Common cold Direct contact with secretions, inhalation/ sinus congestion, sore throat, sneezing, cough, fever, aches, fatigue Ebolavirus RNA Threadlike Ebola structure, enveloped Body fluids/ High fever, uncontrollable bleeding Rubulavirus (rubella virus) RNA Helical, enveloped Mumps, measles Direct contact with infected person or objects, inhalation/ Parotid and salivary gland swelling, possible deafness Flavivirus RNA Hairpin structure Yellow fever Bite of infected mosquito/ rash, fever, nausea, pain, aches, jaundice Viral group Some Common Viruses of Humans Nucleic acid Shape and Structure Example of diseases they cause Mode of Transmission/ Effect on Body Picornaviruses RNA Icosahedral, nonenveloped Poliomylitis, hepatitis A, B, C, & cancer Contaminated blood, food, needles or water. Sexual contact/ Flulike symptoms, swollen liver, jaundice Myxovirus RNA Helical, enveloped Influenza A, B, and C Inhalation/ fever, cough fatigue, sore throat, headache, muscle ache Rhabdoviruses RNA Helical, enveloped rabies Bite of infected animal/ depression, fever, paralysis, fatal Retroviruses RNA Icosahedral, enveloped AIDS, Cancer Sexual contact, contaminated blood or needles/ Immune system failure Viral group Retrovirus • A virus that contains • • • • RNA instead of DNA Genetic information is ENVELOPE copied backwards It may remain dormant for any length of time before becomes active RNA and it can cause death of the host cell. Human Immunodeficiency Virus (HIV) is a retrovirus HIV causes AIDS CAPSID HIV • Transmitted when the body fluids of an infected individual are passed on to an uninfected individual by direct contact or contaminated objects. • Breaks down immune system, so can no longer fight off disease – Hides in Helper T cells • People w/HIV, then AIDS suffer from two rare problems. – Pneumosystis carinii – protozoan infections of lungs – Kaposi’s sarcoma - cancer MEASLES SMALLPOX HERPES Jenner and Pasteur • Edward Jenner, English Doctor…. – Invented vaccine – Infected own son with cow pox (a mild form of small pox) – Son didn’t contract small pox – Cow pox triggered immune system to create an immunity against small pox Jenner and Pasteur • Louis Pasteur –Pasteurization –Disproved spontaneous generation –Said “life came from life” –Boiled broth to kill microorganisms What is an epidemiologist? • A scientist who studies the causes and controls of disease outbreaks. • Involved in preventing disease outbreaks and in stopping outbreaks that do occur spreading. • Work for CDC, FBI, etc. 1918 • http://app.discoveryeducation.com/search ?Ntt=influenza+of+1918 Inoculation & Incubation of culture medium • Culture medium – either a broth or an agar with nutrients added to it to aid in the growth of microorganisms. • Inoculation – referred to as a streak or stab (putting microorganisms in a nutrient agar or broth so they can grow) • Incubation – usually 24 – 48 hours at a temperature of 20º C or 37º C. Inoculation Technique Heat loop Inoculation Inoculation Broth Inoculation Slant Agar Deep Agar Plate Streak Plates Finished Product Koch’s Postulates 1. The pathogen must be found in an animal with the disease and not in a healthy animal. 2. The pathogen must be isolated from the sick animal and grown in a laboratory culture. 3. When the isolated pathogen is injected into a healthy animal, the animal must develop the disease. 4. The pathogen should be taken from the second animal and grown in a laboratory culture. The cultured pathogen should be the same as the original pathogen. Infectious vs. Noninfectious diseases • Infectious disease - Any disease caused by the presence of pathogens in the body –Easily spread from one person to another or from one body part to another • Non-Infectious disease - One that does not spread –Rheumatoid arthritis How is disease spread? • People – Direct contact –Touching –Kissing –Sexual contact • Object – food poisoning • Air, Soil and Water • Vectors – insects: malaria Vaccines and Treatment • http://app.discoveryeducation.com/search ?Ntt=vaccines+and+treatment+of+virus Prevention & Control • Methods of controlling bacterial growth: – Sterilization – heat; most can’t survive high temperatures for long period on time.(kills bacteria) – Disinfectants – soaps & cleaning solutions; sterilizes hospitals; overuse may cause bacteria to evolve.(kills bacteria) – Food storage – refrigeration (bacteria takes longer to multiply at low temperatures); boiling; frying; steaming. – Food processing – canning (heated to high temperature, placed into sterile jars & sealed); chemical treatments such as salt, vinegar,sugar. (kills bacteria) Prevention & Control • Vaccine – a preparation of weakend or killed pathogens. It can prompt the body to produce immunity to the disease. • Immunity – the body’s natural way of killing pathogens. • Antibodies – compounds that block the growth & reproduction of bacteria. – When a bacterial infection occurs, antibiotics can be used to fight the disease. – Animals can suffer from bacterial diseases as well. Ex. Anthrax – sheep to farmers & wool workers which can lead to death. (biological warfare) Active vs. Passive immunity • Immunity – resistance to a particular disease • Active immunity - immunity that you get because you have been exposed to a disease • Passive immunity – immunity that you get because of a vaccine T cells and B cells • Both are white blood cells • Regulated by helper T cells • B cell response – defense that aids the removal of extracellular pathogens – B cells • Stay in lymph nodes & organs • Mature in bone marrow • T cell response – destruction of intracellular pathogen by cytotoxic T cells • Both lymph, organs & circulation • Occur in thymus gland (located in lower neck & thorax) • Act directly against certain pathogens Koch’s Postulates 1. The pathogen must be found in an animal with the disease and not in a healthy animal. 2. The pathogen must be isolated from the sick animal and grown in a laboratory culture. 3. When the isolated pathogen is injected into a healthy animal, the animal must develop the disease. 4. The pathogen should be taken from the second animal and grown in a laboratory culture. The cultured pathogen should be the same as the original pathogen. Infectious v. Noninfectious diseases • Infectious disease - Any disease caused by the presence of pathogens in the body –Easily spread from one person to another or from one body part to another • Non-Infectious disease - One that does not spread –Rheumatoid arthritis Mutations • http://app.discoveryeducation.com/search ?Ntt=mutations+in+virus Specific vs. Nonspecific • Nonspecific – always present, fights off anything foreign to the body. –2 lines of defense (1 outside, 1 inside) • Specific – body has been exposed to disease before (immunity to chicken pox once you have already had the disease) Specific vs. Nonspecific • 1st line of nonspecific defense – Mucous membranes – traps it before it can enter the body – Skin – acts as a physical barrier – Sweat – contains lysozyme (which digest bacterial walls) • 2nd line of nonspecific defense – Inflammatory response – Temperature response – Proteins – White blood cells 2nd Line of Defense cont. • Inflammatory response 2nd Line of Defense cont. • Temperature response –Disease causing bacteria don’t grow well at high temperatures –Normal body temperature 37º C (98.6º F) –> 39º C (103º F) – dangerous –>41º C (105º F) - fatal 2nd Line of Defense cont. • Protein complement system – About 20 different proteins circulate in the blood and became active when they encounter certain pathogens by attaching to the surface of proteins and damaging plasma membrane. • Interferons – Protein is released by cells infected with virus which causes nearby cells to produce an enzyme that prevents viruses Specific vs. Nonspecific • • • • • SPECIFIC RESPONSE White Blood Cells – produced in bone marrow and circulate in the blood and lymph nodes Macrophage – consume pathogens and infected cells Cytotoxic (killer) T cells – attack & kill infected cells B cells – label invaders for later destruction by macrophages Helper T cells – activate cytotoxic T cells & B cells SPECIFIC RESPONSE • Infected cell has an antigen (substance that triggers an immune response) of an invader on its surface • White blood cells are covered with receptor proteins that respond to infection by binding to specific antigens on the surfaces of the infecting microbes • They recognize and bind to antigens that match their particular shape. Polio Panic • http://app.discoveryeducation.com/search ?Ntt=polio+panic Allergies • Occur when antigens bind to mast cells. • Activate mast cells which release histamines. –Histamines produce sneezing, runny eyes & nose Common Antigens that cause allergies • Foods • Dust – Milk, eggs • Antibiotics – Penicillin • Cosmetics • Pollen • Molds • Microbes • Chemicals in plants – poison ivy Autoimmune diseases • A disease in which the immune system starts attacking body cells as if they were pathogens. • Affect organs and tissues in different parts of the body. • Graves disease, Multiple sclerosis (MS), Rheumatoid arthritis, Systemic lupus erythematosus (SLE), Type I diabetes Some Autoimmune Diseases • Rheumatoid Arthritis – exact cause is unknown, but clear the immune system is involved. – Involves inflammation of joint, swelling, pain & loss of function. • Rheumatic Fever – happens when streptococcus bacteria causes a disease known as strep throat. – If left untreated, the immune system produces antibodies that destroy bacteria. • Multiple sclerosis – result of destruction by immune system of special cells that surround nerve fibers and permit rapid impulse transmission. Autoimmune diseases, cont. • Lupus – exact cause unknown, although it is certain that both environment & genetic factors are involved. – Believed a genetic pre-disposition to the disease • Symptoms include: – Achy joints, 100°F + fever, Arthritis, Prolonged or extreme fatigue, Skin rashes, Anemia, Kidney disorders • Factors that trigger Lupus: – Infections, Antibiotics, Ultra-violet lights, Extreme stress, Hormones Understanding Virus part 2 • http://app.discoveryeducation.com/search ?Ntt=understanding+virus