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BACTERIA!! (Formerly Kingdom Monera) EUKARYOTES PROKARYOTES EUBACTERIA ARCHAEABACTERIA Bacteria Cell Structures Prokaryotes (Bacteria) Eubacter "True" bacteria – human pathogens – clinical or environmental – one kingdom Archaea – Environmental organisms – second kingdom Bacteria are of immense importance because of their rapid growth, reproduction, and mutation rates, as well as, their ability to exist under adverse conditions. The oldest fossils known, nearly 3.5 billion years old, are fossils of bacterialike organisms. More Characteristics of Bacterial Cells 1. They are prokaryotes (no membrane bound nucleus or organelles) 2. Bacterial cells have a single chromosome. 3. Most bacteria reproduce by binary fission. 4. Bacteria show great metabolic diversity. 5. Found as single cells or in groups of two or more (called a colony) Bacteria can be autotrophs or hetertrophs. Those that are classified as autotrophs are either photosynthetic, obtaining energy from sunlight or chemosynthetic, breaking down inorganic substances for energy . Bacteria classified as heterotrophs derive energy from breaking down complex organic compounds in the environment. This includes saprobes, bacteria that feed on decaying material and organic wastes, as well as those that live as parasites, absorbing nutrients from living organisms. Depending on the species, bacteria can be aerobic which means they require oxygen to live or anaerobic which means oxygen is deadly to them. Green patches are green sulfur bacteria. The rust patches are colonies of purple non sulfur bacteria. The red patches are purple sulfur bacteria. Archaebacteria 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 11 Eubacteria Cyanobacteria This is a group of bacteria that includes some that are single cells and some that are chains of cells. You may have seen them as "green slime" in your aquarium or in a pond. Cyanobacteria can do "modern photosynthesis", which is the kind that makes oxygen from water. All plants do this kind of photosynthesis and inherited the ability from the cyanobacteria. Cyanobacteria were the first organisms on Earth to do modern photosynthesis and they made the first oxygen in the Earth's atmosphere. Bacteria are often maligned as the causes of human and animal disease. However, certain bacteria, the actinomycetes, produce antibiotics such as streptomycin and nocardicin. Other Bacteria live symbiotically in the guts of animals or elsewhere in their bodies. For example, bacteria in your gut produce vitamin K which is essential to blood clot formation. Still other Bacteria live on the roots of certain plants, converting nitrogen into a usable form. Bacteria put the tang in yogurt and the sour in sourdough bread. Saprobes help to break down dead organic matter. Bacteria make up the base of the food web in many environments. Streptococcus thermophilus in yogurt Bacteria are prokaryotic and unicellular. Bacteria have cell walls. Bacteria have circular DNA called plasmids Bacteria can be anaerobes or aerobes. Bacteria are heterotrophs or autotrophs. Bacteria are awesome! Bacteria can reproduce sexually by conjugation or asexually by binary fission. Binary Fission Endospore Bacteria can survive unfavorable conditions by producing an endospore. Shapes of 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 25 Name the Type Name the Type Name the Type Name the Type Name the Type Penicillin, an antibiotic, comes from molds of the genus Penicillium Notice the area of inhibition around the Penicillium. Penicillin kills bacteria by making holes in their cell walls. Unfortunately, many bacteria have developed resistance to this antibiotic. The Gram stain, which divides most clinically significant bacteria into two main groups, is the first step in bacterial identification. Bacteria stained purple are Gram + - their cell walls have thick petidoglycan and teichoic acid. Bacteria stained pink are Gram – their cell walls have have thin peptidoglycan and lipopolysaccharides with no teichoic acid. In Gram-positive bacteria, the purple crystal violet stain is trapped by the layer of peptidoglycan which forms the outer layer of the cell. In Gram-negative bacteria, the outer membrane of lipopolysaccharides prevents the stain from reaching the peptidoglycan layer. The outer membrane is then permeabilized by acetone treatment, and the pink safranin counterstain is trapped by the peptidoglycan layer. Is this gram stain positive or negative? Identify the bacteria. Is this gram stain positive or negative? Identify the bacteria. Gram staining tests the bacterial cell wall's ability to retain crystal violet dye during solvent treatment. Safranin is added as a mordant to form the crystal violet/safranin complex in order to render the dye impossible to remove. Ethyl-alcohol solvent acts as a decolorizer and dissolves the lipid layer from gram-negative cells. This enhances leaching of the primary stain from the cells into the surrounding solvent. Ethyl-alcohol will dehydrate the thicker grampositive cell walls, closing the pores as the cell wall shrinks. For this reason, the diffusion of the crystal violet-safranin staining is inhibited, so the bacteria remain stained. 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 STREP THROAT Strep Throat SALMONELLA LYME DISEASE BOTULISM Leprosy is a bacterial infection that decreases blood flow to the extremities resulting in the deterioration of toes, ears, the nose and the fingers. Helicobacter pylori is the pathogenic bacteria that can causes ulcers 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 Importance of Bacteria Human disease (strep, food poisoning, wound infections, etc.) Disease in animals and plants Food spoilage HOWEVER, only a small % of bacterial species are actually harmful Importance of Bacteria Decomposers Produce vitamins in the human intestine Vinegar, yogurt and cheese are made using bacteria Some bacteria produce antibiotics Fuel can be produced (methane) from metabolized wastes from some Natural pesticides: infect caterpillars that destroy crops. Help produce Vitamin K in our intestines (used for blood clotting) Some bacteria (the flavobacterium) eat the poison pentoclorophenol, found in wood preservative. Once the toxin is removed the microbe dies. Text Assignment Read pages 471 to 477 and complete the following: Q1-6 on page 477 Review your PPT notes