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Microbiology Bacteria, Viruses, Protists, and Fungi Bacteria Bacteria are classified into two kingdoms: Eubacteria (true bacteria) and Archaebacteria (Ancient Bacteria). Until recently, bacteria were placed into one Kingdom - The Kingdom Monera, hence sometimes bacteria are referred to as Monerans Bacteria Bacteria are the MOST NUMEROUS ORGANISMS ON EARTH Bacteria have evolved into many different forms, and they are now part of nearly every environment on Earth They have been found at the bottom of the oceanic trenches 9.6 km (6 mi) below the water's surface and in Arctic and Antarctic Regions. Reactivity with Oxygen Obligate Aerobes - require oxygen for respiration, need oxygen to grow and survive Obligate Anaerobes - must avoid oxygen, they will die in its presence Facultative Anaerobes - can use oxygen when it is available, but can also do without it Archaebacteria Archaebacteria tend to live in extreme environments - sometimes they are called "Extremophiles" Halophiles - salt lovers Methanogens - produce methane as a by-product Thermoacidophiles - love hot, acidic environments Eubacteria Classified according to their mode of getting nutrients, mechanism of movement, and their shape Shape of Bacteria / Naming Cocci - sphere Bacilli - rods Spirilla - spirals Diplo - in pairs Staph - in clusters Strep - in chains Bacteria Morphology Structures that help bacteria survive in hostile environments capsules (slime layers) - help evade immune system and adhere to surfaces pili - hairlike projections endospores - bacteria become dormant until conditions become favorable Bacteria Morphology Movement Flagella – one or more tail-like structures Reactions chemotaxis - response to chemicals phototaxis - response to light magnetotaxis - response to magnetic field Gram Stain Gram's Stain is a widely used method of staining bacteria as an aid to their identification. It was originally devised by Hans Christian Joachim Gram, a Danish doctor. Gram's stain differentiates between two major cell wall types. Gram-Negative: Bacterial species with walls containing small amounts of peptidoglycan Gram-Positive: Bacteria with walls containing relatively large amounts of peptidoglycan Gram Negative – light red or pink color Gram Positive + dark purple Escherichia coli, Salmonella typhi, Vibrio cholerae and Bordetella pertussis Staphylococcus epidermidis, Streptococcus pyogenes, and Clostridium tetani Bacterial Reproduction Occurs by binary fission - one cell splits into two cells, offspring are genetically identical to parent Bacterial conjugation - a form of sexual reproduction where bacteria exchange genetic information before dividing, offspring have new genes (and new traits) Bacterial Reproduction Transformation - bacteria incorporate genes from dead bacteria Transduction - viruses insert new genes into bacterial cells. This method is used in biotechnology to create bacteria that produce valuable products such as insulin Bacterial Transformation Bacteria and Health Some diseases caused by bacteria: Tetanus Botulism Syphilis Lyme disease Strep throat Pneumonia Anthrax Necrotizing fasciitis (flesh eating bacteria) Toxic shock syndrome Treatments Antibiotics & Antiseptic solutions Antibiotics and Antiseptics Joseph Lister created the first antiseptic, an acid to spray on tables and instruments before surgery (1860) The Discovery of Penicillin Alexander Fleming Noticed mold growing on petri dishes Bacteria did not grow where the mold was He isolated the chemical that killed bacteria, but it was not stable Howard Flory continued the work, later stabilized the chemical Fleming and Flory received the Nobel Prize in 1945 Viruses Properties of viruses Possess no membranes, cytoplasm, ribosomes, or other cellular components Cannot move or grow Can only reproduce inside a host cell Consist of 2 major parts - a protein coat, and hereditary material (DNA or RNA) Extremely tiny, much smaller than a cell and only visible with advanced electron microscopes Viruses and their Hosts Viruses are specific to their hosts. They can only attack specific cells, and not all viruses can pass between different species (though some can). Rabies, for instance, can be passed from animal to human. HIV is a virus that seems specific to humans. Viruses and their Hosts The common cold is a virus that specifically attacks cells of the respiratory track (hence the coughing and sneezing and sniffling). Other viruses attack other types of cells. HIV virus specifically attacks white blood cells. Influenza Influenza, often called the FLU, is an acute, highly contagious infection of the respiratory tract which commonly occurs in the winter. Influenza results from different strains of the influenza virus. This virus has the ability to mutate into different forms. That is why although you were exposed to similar strains in the past, you might not be able to defend yourself against a new one. Symptoms Vaccine Flu Virus Smallpox Virus Incubation period before symptoms:10-14 days Symptoms: high fever, headache, backache, and vomiting, rash (pox) on the face and arms that spreads to the trunk How it would be spread Aerosol or person-to-person, potentially by a terrorist-"martyr." It is highly contagious. However, smallpox victims show clear signs of the disease, and anyone who came in contact with them could be vaccinated post-exposure. Treatment: There is no current treatment against the smallpox virus. Vaccination given 3-5 days post-exposure can prevent the disease. Vaccine:Vaccine exists but is currently not recommended for the general public. Stockpiles of vaccine are being increased. No one in the U.S. has been vaccinated since 1972, and people vaccinated before then have likely lost immunity. Variola (Smallpox) Virus Smallpox Streptococcus Strep throat is an infection caused by group A streptococcus bacteria, and it's very common among kids and teens. The symptoms of strep throat include fever, stomach pain, and red, swollen tonsils. Strep throat usually requires treatment with antibiotics. With the proper medical care - along with plenty of rest and fluids - your child should be back to school and play within a few days. Strep Throat HIV HIV Animation Human immunodeficiency virus (HIV) is a that can lead to AIDS, a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infection. Previous names for the virus include human Tlymphotropic virus-III (HTLV-III), lymphadenopathy-associated virus (LAV), and AIDS-associated retrovirus (ARV). Infection with HIV occurs by the transfer of blood, semen, vaginal fluid, preejaculate, or breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells. The four major routes of transmission are unprotected sex, contaminated needles, breast milk, and transmission from an infected mother to her baby at birth. Screening of blood products for HIV has largely eliminated transmission through blood transfusions or infected blood products in the developed world. HIV infection in humans is now pandemic. As of January 2006, the UNAIDS and the WHO estimate that AIDS has killed more than 25 million people since it was first recognized on Dec. 1, 1981, making it one of the most destructive pandemics in recorded history. Related to Viruses Viroids - even smaller than viruses, consist of RNA strands that lack a protein coat Prions - infectious agents that are believed to be the cause of Mad Cow Disease, relatively new find and much is not known about them Bacteriophage - viruses that infect bacteria Viral Reproduction Lysogenic (Prophage) Pathway - the virus stays within the cell until certain environmental triggers cause it to enter the lytic cycle Lytic Pathway - rapid replication of the virus, ending in cell lysis (or death). More phages are released to infect other cells Lysogenic Cycle Lytic Cycle A: Virus attaches to host and injects its nucleic acid B: Viral nucleic acids and proteins are made C: New virus particles are assembled D: Host cell breaks open and virus particles are released to infect other cells Protists Protists are divided into 3 major categories Plantlike Protists Animal-like Protists Photosynthetic algae Heterotrophic called protozoa ("first animal") Fungus-like Protists resemble fungi absorptive protists slime molds and water molds Plant-Like Protists Dinoflagellata - 2 flagella Golden Algae – chrysophyta Green Algae – chlorophyta Brown Algae – phaeophyta Red Algae – rhodophyta Diatoms - major component of plankton Green Algae (Spyrogyra) Diatoms Animal-Like Protists Rhizopoda move using pseudopods (false feet), ex. ameba, eat by phagocytosis Foraminifera have a shell, some have photosynthetic algae in the shell Actinopoda helizoans and radiozoans Apicomplexa parasitic protists, formerly known as sporozoa, Malaria is caused by a protist in this group Zooflagellates have a flagella, member of this group causes African Sleeping Sickness Ciliophora use cilia to move, live in water, ex. paramecium Ameba Paramecium Radiolarian Fungus-like Protists Myxomycota - slime molds, produce spores to reproduce, they grow and eat as a mass Acrasiomycota - cellular slime molds, solitary but can work together Oomycota - water molds Slime Molds Fungi Characteristics Habitat Air, food, gardens, and water Warm temperatures (2030°) Once classified as plants because: Grow anchored in soil Cell walls Fungi Characteristics Structure Cell walls – made of chitin Hyphae Anchor the fungus Invade food source Form reproductive structures Septa Divide the hyphae into individual cells Fungi Types Saprophytes Mutualists Decomposers that feed on dead organic material Symbiotic relationship (ex. Algae) Parasitic fungi Absorb nutrients from hosts Fungi Adaptations Role Benefits of increased surface area (hyphae) Decompose Earth’s organic wastes Nutrient absorption What would happen if there were no fungi? Huge amounts of waste, dead organisms, and debris would litter the Earth Fungi Reproduction Fragmentation Pieces of hyphae are broken by mycellium and grow into new mycelia Budding Asexual reproduction – mitosis occurs and new individuals pinch off from parent Fungi Reproduction continued… Spores (reproductive cells) Spores transported to a favorable location Hypha emerge and begin to grow Advantages of Spore Reproduction Sporangia protect spores (from drying out) Large number of spores increase germination rate and increase survival rate Lichens Symbiotic relationship between a fungus and an alga or cyanobacteria