Chapter 19: Bacteria Edwin P. Davis, M.Ed. 11/23/2018

Bacteria 11/23/2018

Bacteria 11/23/2018

Classification of Bacteria Archaebacteria The extremists Oxygen – free environments Produce methane Concentrated salt water environments Great Salt Lake, UT The Dead Sea, Middle East Hot, acidic waters of sulfur springs The Dead Sea, Israel The Great Salt Lake, UT 11/23/2018

Eubacteria The heterotrophs Found everywhere Need organic molecules as an energy source Parasites Absorb nutrients from living organisms Saprobes Organisms that feed on dead organisms or organic waste Help recycle the nutrients contained in decomposing organisms Saprobe 11/23/2018

The photosynthetic autotrophs Obtain energy from light Cyanobacteria (cyano, blue-green) Trap the sun’s energy by photosynthesis using their blue-green pigment Some are red or yellow Found in ponds, streams and moist land Composed of chains of cells Exception to unicellular rule 11/23/2018

The Chemosynthetic autotrophs Obtain energy from chemosynthetic breakdown of inorganic substances sulfur or nitrogen compounds Important in converting nitrogen in the atmosphere to forms readily used by plants Underwater sea vent 11/23/2018

Bacteria At the center of the cell is usually a single chromosome.  Like the DNA or RNA in animal or human cells, the bacterial chromosome has full capability to replicate itself.   Bacterial Cell Structure 11/23/2018

Bacteria Unlike higher organisms, the bacteria's chromosome is not protected from the cytoplasm (fluid of the cell) by a nuclear membrane (such as in the nucleus of a protozoan). Also, bacteria may have extra pieces of DNA (called plasmids), as well as ribosomes (they help the chromosome replicate) in the cytoplasm. 11/23/2018

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Structure of Bacteria Microscopic, simple, living Prokaryotic, no true nucleus Non-membrane bound organelles Ribosomes smaller Inherited information held in single circular chromosome As opposed to paired chromosomes 11/23/2018

Eukaryotic & Prokaryotic Cells 11/23/2018

Prokaryotes are identified by: Prokaryotic Cells Prokaryotes are identified by: Their shape Their chemical nature of their cell walls The way they move The way they obtain energy 11/23/2018

Prokaryotic Cell shape 3 main cell shapes Bacilli – Rod shape Cocci – spherical shaped Spirilla – Spiral & corkscrew 11/23/2018

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Shapes of Bacteria Shape Spheres coccus Rods bacillus Spiral spirillum 11/23/2018

Prokaryotic Cell shape 11/23/2018

Bacteria Morphology 11/23/2018

Bacterial Cell Arrangement Diplo – cells are paired Staphylo – cells are in grape-like clusters Strepto – cells are in long chains 11/23/2018

Bacteria Morphology  Introduction: Bacteria, fungi and other microorganisms are the main cause of most disease or other unpleasant symptoms. We try to avoid such organisms by staying away from polluted or infected places and by using personal hygiene products such as soaps, detergents and antibacterial agents. Despite all our efforts, bacteria are present almost everywhere, and some bacteria can make us sick.  11/23/2018

Prokaryotic Cells Cells that lack a membrane-bound nucleus are called prokaryotes (from the Greek meaning before nuclei). Prokaryotic cells don't have a membrane-bound nucleus and instead of having chromosomal DNA, their genetic information is in a circular loop called a plasmid. 11/23/2018

Prokaryotic Cell Walls 2 different cell walls Gram Positive Cell Wall – thick peptidoglycan walls Gram Negative Cell Wall – thinner peptidoglycan walls 11/23/2018

Bacillus Anthracis Cerebrospinal fluid Prokaryotic cell wall Gram Positive Stain Bacillus Anthracis Cerebrospinal fluid 11/23/2018

Prokaryotic Cells Bacteria perform many important functions on earth. They serve as decomposers, agents of fermentation, and play an important role in our own digestive system. 11/23/2018

Protection from osmotic pressure Cell walls Made of long chains of sugar linked by short chain amino acids Prevent osmotic rupture Most bacteria live in hypotonic environment Water always enter in Cell wall prevents bursting of cell If ruptured, cell dies 11/23/2018

Examples of Prokaryotic Cells 11/23/2018

Eukaryotic Cells Eukaryotic cells (from the Greek meaning truly nuclear) comprise all of the life kingdoms except Monera. They can be easily distinguished through a membrane-bound nucleus. 11/23/2018

Eukaryotic Cell Examples Picture of a Bread Yeast - (from the fungi kingdom) Picture of a Centric Diatom (from the Protista kingdom) 11/23/2018

Eukaryotic Cell Examples Human Red Blood Cells, Platelets, and T-lymphocytes (from the Animalia kingdom Human Liver Cell (from the Animalia kingdom) 11/23/2018

Prokaryotic Vs. Eukaryotic Cells 11/23/2018

Penicillin – Bacterial Killer? Interferes with the enzyme that links the sugar chains in the cell wall Bacteria growing in penicillin develop holes in their cell walls Water enters, bacteria dies Not effective in viruses and animals Neither has cell walls Nontoxic to plants Plant cell wall is different structure from bacterial cell wall 11/23/2018

Miracle Cure – The Story of Penicillin Discovered by Alexander Fleming in 1928 Produced from an airborne mold, Penicillium notatum World’s first antibiotic Purified in 1940 Kills bacteria and inhibit their growth Killed his dish of staphylococcus Streptomycin, second leading antibiotic, discovered in 1943 Penicillium notatum 11/23/2018

Ecology and Adaptation Diversity of metabolism Obligate aerobes Bacteria that require oxygen for cellular respiration Mycobacterium tuberculosis Person with TB 11/23/2018

Post primary Tuberculosis (“Reactivation TB”) Most cases in adults occur as reactivation of a primary focus of infection acquired in childhood Limited mainly to the apical and posterior segments of the upper lobes and the superior segments of the lower lobe 11/23/2018

Tuberculosis 11/23/2018

Obligate anaerobes Cannot use oxygen Are killed by it You cannot get syphilis from toilet seat. Syphilis - causing bacteria 11/23/2018

Complex biochemical pathways Green sulfur bacteria Use hydrogen sulfide instead of water for photosynthesis Produce sulfur instead of oxygen Grow in anaerobic environments like lake sediments Green sulfur bacteria 11/23/2018

Adaptations for survival Endospores Have hard outer covering Resist drying out, boiling, freezing, many chemicals Bacteria is in slow metabolism, does not reproduce When in favorable conditions, germinates and gives rise to bacterial cell 11/23/2018

Clostridium botulinum Obligate anaerobes Form endospores Produces an extremely powerful toxin (poison) Don’t die when exposed to oxygen Can find their way into canned food If not properly sterilized endospores germinate bacteria grow produce their deadly toxin Causes botulism 11/23/2018

Clostridium tetani Produces powerful nerve toxin Causes often-fatal disease, tetanus Endospores are found in every surface Can enter wound easily, germinate and release toxin Immunization is prevention 11/23/2018

Anthrax Anthrax is primarily a disease of animals, however, it can occasionally be transmitted to humans. The disease is caused by Bacillus antracis, a Gram positive, rod shaped, and endospore forming microorganism. Endospore formation is necessary in times of unfavorable living conditions (e.g. low water availability, extremely high temperatures, etc.). The bacteria remains dormant until environmental conditions becomes suitable for living 11/23/2018

ANTHRAX Transmission to humans can occur by direct contact of the skin with the endospores of B. antracis, via the respiratory tract through inhalation of spores, and via the gastrointestinal tract through the ingestion of spores. If disease is inhaled Mild Fever, Malaise Fatigue, Coughing Feeling of pressure on chest If disease contract through skin a boil develops that eventually forms a black center 11/23/2018

Bacteria Reproduction 11/23/2018

1. Binary Fission Asexual reproduction Copies its single chromosome Copies attach to cell’s plasma membrane Cell divides into two as partition forms between two new cells Each cell has one copy of chromosome Just like mitosis, but the whole organism is copied 11/23/2018

Binary fission 11/23/2018

2. Conjugation Sexual reproduction One bacterium transfers all or part of its chromosome to another Pilus (pili) Bridge-like structure Connects two cells Used to transfer genetic material 11/23/2018

Conjugation 11/23/2018

Bacteria Economic Importance 11/23/2018

Bacteria on legume roots Nitrogen fixation Convert N2 gas into ammonia (NH3) Convert ammonia (NH3) to nitrite (NO2-) and nitrate (NO3-) Some form symbiotic relationship with peas, peanuts, and soybeans Helps them grow better when nitrogen is lacking When they are harvested, remaining roots add nitrogen to soil Bacteria on legume roots 11/23/2018

Recycling of nutrients Cyanobacteria Replenish supply of oxygen in atmosphere Autotrophic bacteria Convert carbon dioxide in the air to the organic compounds that are passed to consumers in food chains and webs All life depend on bacteria 11/23/2018

Food and medicines Used to produce vinegar, yogurt, butter, cheese, pickles, sauerkraut Used to produce antibiotics to kill other bacteria Streptomycin Erythromycin Chloromycetin Kanamycin 11/23/2018

Bacteria cause disease Half of human disease is caused by bacteria Tuberculosis Scarlet fever Rocky Mountain spotted fever Bacterial pneumonia Syphilis Tetanus Botulism Gonorrhea Ear infections Strep throat Chlamydia Boils Staph infections Diphtheria Lyme disease 11/23/2018