What are bacteria? How are they classified? Are they good or bad? Warm Up

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What are the 6 Kingdoms? Archaebacteria Archaebacteria Eubacteria Eubacteria Protists Protists Fungi Fungi Plants Plants Animals Animals Monera

Kingdom Monera Most numerous organism on Earth Most Ancient Microscopic Prokaryotes Evolution has yielded many species adapted to survive where no other organisms can. Grouped based on: Structure, physiology, molecular Composition, reaction to specific types of stain. Eubacteria= Germs/bacteria Archaebacteria

Archaebacteria Live in extreme locations: Live in extreme locations: –Oxygen-free environments –Concentrated salt-water –Hot, acidic water Methanogens make methane (natural gas Halophiles can turn extremely salty environments pink Thermophiles can grow In hot springs and boiling water Methanogens

Eubacteria Heterotrophs –found everywhere and lives off living/dead organisms Heterotrophs –found everywhere and lives off living/dead organisms Photosynthetic autotrophs – makes their own food Photosynthetic autotrophs – makes their own food Chemosynthetic autotrophs Chemosynthetic autotrophs The first organisms on Earth to do modern photosynthesis

What are bacteria? Single celled organisms Very small Need a microscope to see Can be found on most materials and surfaces Billions on and in your Billions on and in your body right now body right now E. Coli O157:H7 can make you very sick. Streptococcus can cause strep throat. This E. coli helps you digest food. This is a pore in human skin and the yellow spheres are bacteria

9 Bacteria compared to a white blood cell that is going to eat it Bacteria

10 Clean skin has about 20 million bacteria per square inch

What do they look like? Three basic shapes Three basic shapes –Rod shaped called bacilli (buh-sill-eye) –Round shaped called cocci (cox-eye) –Spiral shaped Some exist as single cells, others Some exist as single cells, others cluster together Bacilli Spiral Cocci Cluster of cocci USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Bacteria are ALIVE! What does it mean to be alive? What does it mean to be alive? –They reproduce (make more of themselves) –They need to eat USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

How do bacteria reproduce? Grow in number not in size Grow in number not in size –Humans grow in size from child to adult Make copies of themselves by dividing in half Make copies of themselves by dividing in half –Human parents create a child USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

15 Binary Fission- the process of one organism dividing into two organisms Fission is a type of asexual reproduction Reproduction of Bacteria How?... The one main (circular) chromosome makes a copy of itself Then it divides into two Asexual reproduction- reproduction of a living thing from only one parent Bacteria dividing Completed

A closer look at how Bacteria reproduce Binary Fission – reproduction in which a bacteria cell divides into two cells that are the same as the original. They can reproduce in 15 minutes if resources are available. Binary Fission – reproduction in which a bacteria cell divides into two cells that are the same as the original. They can reproduce in 15 minutes if resources are available.

How do bacteria eat? Some make their own food from sunlight—like plants Some make their own food from sunlight—like plants Some are scavengers Some are scavengers –Share the environment around them  Example: The bacteria in your stomach are now eating what you ate for breakfast Some are warriors (pathogens) Some are warriors (pathogens) –They attack other living things  Example: The bacteria on your face can attack skin causing infection and acne Photosynthetic bacteria Harmless bacteria on the stomach lining E. Coli O157:H7 is a pathogen USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Bacteria are of immense importance because of their rapid growth, reproduction, and mutation rates, as well as, their ability to exist under adverse conditions. 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 bacteria-like organisms. The oldest fossils known, nearly 3.5 billion years old, are fossils of bacteria-like organisms.

Bacteria are often maligned as the causes of human and animal disease. However, certain bacteria, the actinomycetes, produce antibiotics such as streptomycin and nocardicin. Bacteria are often maligned as the causes of human and animal disease. However, certain bacteria, the actinomycetes, produce antibiotics such as streptomycin and nocardicin.

What is a pathogen? Bacteria that make you sick Bacteria that make you sick –Why do they make you sick?  To get food they need to survive and reproduce –How do they make you sick?  They produce poisons (toxins) that result in fever, headache, vomiting, and diarrhea and destroy body tissue USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Where do you get a pathogen? Contact with people who are sick Contact with people who are sick –Direct or indirect Food, Water, or other Surfaces that are contaminated Food, Water, or other Surfaces that are contaminated Indirect contact Direct contact Foods that could be contaminated USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

A Closer Look – Where do you get a pathogen Indirect Contact Direct Contact Foods and water may be contaminated USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Are all bacteria pathogens? No, most are harmless No, most are harmless Some are even helpful Some are even helpful –Examples of helpful bacteria:  Lactobacillus: makes cheese, yogurt, & buttermilk and produces vitamins in your intestine  Leuconostoc: makes pickles & sauerkraut  Pediococcus: makes pepperoni, salami, & summer sausage USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

A Closer Look – Helpful Bacteria Pediococcus - used in production of fermented meats Leuconostoc cremoris – used in the production of buttermilk and sour cream Lactobacillus casei – found in human intestines and mouth to improve digestion Lactobacillus bulgaricus – used in the production of yogurt USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Other Bacteria live symbiotically in the guts of animals or elsewhere in their bodies. Other Bacteria live symbiotically in the guts of animals or elsewhere in their bodies. E.coli on small intestines 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. Still other Bacteria live on the roots of certain plants, converting nitrogen into a usable form.

What are some common pathogens? Pathogenic E. coli Pathogenic E. coli (like O157:H7) –Found in ground beef, contaminated fruits and vegetables Salmonella Salmonella –Found in raw meats, poultry, eggs, sprouts, fruit and vegetables Listeria Listeria –Found in deli foods, lunch meats, smoked fish and vegetables E. coli O157:H7 Salmonella Listeria USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Examples of Pathogens Salmonella Staphylococcus aureus Campylobacter jejuni E. coli O157:H7 What shape are these bacteria? Cocci, bacilli, or spiral? USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Kingdom Protists

Protista can be Pathogens The Protista kingdom includes Algae, and Protozoans. They may have features like those of plants, animals, and fungi. They may be single celled or multicellular. The Protista kingdom includes Algae, and Protozoans. They may have features like those of plants, animals, and fungi. They may be single celled or multicellular.

Protist can reproduce sexually or asexually Meiosis Meiosis Budding and Fission Budding and Fission

Common Protista Pathogens Sporozoan – lives in blood and may cause malaria. Sporozoan – lives in blood and may cause malaria. Trypanosome – lives in blood and may cause sleeping sickness. Trypanosome – lives in blood and may cause sleeping sickness. Entamoeba histolytica – lives in the intestines andd can cause severe diarrhea. Entamoeba histolytica – lives in the intestines andd can cause severe diarrhea.

How do they move ? Groups are based on movement. This includes movement by Groups are based on movement. This includes movement by flagella, cilia, pseudopods. flagella, cilia, pseudopods. false feet’ Whip like structure Hair like structure Streaming cytoplasm

Viruses

What are Viruses? Viruses and smaller than bacteria and much smaller than eukaryotes. Viruses and smaller than bacteria and much smaller than eukaryotes. They consist of a shell made of protein and lipid which protect the genetic material inside. They consist of a shell made of protein and lipid which protect the genetic material inside. They are not alive and none are helpful. They are not alive and none are helpful.

How do Viruses reproduce? Viruses cannot reproduce or express their genes without the help of a living cell. Once a virus has "infected" a cell, it will “control" the cell's ribosomes, enzymes and much of the cellular machinery to reproduce. Viral reproduction produces many, many progeny, that when complete, leave the host cell to infect other cells in the organism. Viruses cannot reproduce or express their genes without the help of a living cell. Once a virus has "infected" a cell, it will “control" the cell's ribosomes, enzymes and much of the cellular machinery to reproduce. Viral reproduction produces many, many progeny, that when complete, leave the host cell to infect other cells in the organism.

How do Viruses reproduce? How do Viruses reproduce?

Diseases cased by Viruses Avian or Bird Flu Avian or Bird Flu Swine Flu Swine Flu Meningitis Meningitis Mononucleosis Mononucleosis Warts Warts Hepatitis Hepatitis Bronchiolitis Bronchiolitis Colorado Tick Fever Colorado Tick Fever Encephalitis Encephalitis Common Cold Common Cold HIV-AIDS HIV-AIDS Influenza Influenza Measles (Rubella) Measles (Rubella) Mumps Mumps Polio Polio Rabies Rabies Smallpox Smallpox Hepatitis Hepatitis Herpes Herpes

Fungi

What is a Fungi? Fungi are Eukaryotic heterotrophs and are unicellular and multicellular Fungi are Eukaryotic heterotrophs and are unicellular and multicellular Some live as saprophytes (live on rotting organic matter) Some live as saprophytes (live on rotting organic matter) They perform a crucial role in nature by decomposing dead organisms They perform a crucial role in nature by decomposing dead organisms Some live in a mutually beneficial symbiotic relationship Some live in a mutually beneficial symbiotic relationship

How do Fungi Reproduce Asexually They produce spores They produce sporesSexually Budding – Buds that break of from the parent and produce an identical copy Budding – Buds that break of from the parent and produce an identical copy Meiosis – sharing DNA wit similar fungi Meiosis – sharing DNA wit similar fungi

Examples of Fungi yeasts molds mildews Yeast: Candida albicans Mushrooms

How can I avoid pathogens? Wash your hands often so you won’t transfer bacteria to your mouth or food Wash your hands often so you won’t transfer bacteria to your mouth or food –Warm water with soap for 20 seconds, rub hard between fingers and nails USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Cook food thoroughly to kill any pathogens that may be in your food Cook food thoroughly to kill any pathogens that may be in your food Store food properly to limit pathogen growth Store food properly to limit pathogen growth –Cold temperatures (40  F) How can I avoid pathogens? USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

49 Controlling Bacteria Antiseptic vs. Disinfectants Antiseptic- chemicals that kill bacteria on living things means – “against infection” Examples: iodine, hydrogen peroxide, alcohol, soap, mouthwash Disinfectants- stronger chemicals that destroy bacteria on objects or nonliving things

Bacteria are prokaryotic and unicellular. Bacteria are prokaryotic and unicellular. Bacteria have cell walls. Bacteria have cell walls. Bacteria have circular DNA called plasmids Bacteria have circular DNA called plasmids Bacteria can be anaerobes or aerobes. Bacteria can be anaerobes or aerobes. Bacteria are heterotrophs or autotrophs. Bacteria are heterotrophs or autotrophs. Bacteria are awesome! Bacteria are awesome! Review

Review Bacteria, Fungi, and Protista are living organisms Bacteria, Fungi, and Protista are living organisms Most are harmless Most are harmless A few are pathogens that make you sick A few are pathogens that make you sick You can reduce the risk of getting sick by washing your hands and handling food properly. You can reduce the risk of getting sick by washing your hands and handling food properly. USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Review Shapes of Bacteria

Stained Bacteria Cells

Stained Protozoa cells

Stained Fungi cells

Bacteria can reproduce sexually by conjugation or asexually by binary fission. Bacteria can reproduce sexually by conjugation or asexually by binary fission.

Endospore Bacteria can survive unfavorable conditions by producing an endospore. Bacteria can survive unfavorable conditions by producing an endospore.

Penicillin kills bacteria by making holes in their cell walls.walls Unfortunately, many bacteria have developed resistance to this antibiotic. Penicillin, an antibiotic, comes from molds of the genus Penicillium Notice the area of inhibition around the Penicillium.

The Gram stain, which divides most clinically significant bacteria into two main groups, is the first step in bacterial identification. 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 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. 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.

The Gram stain has four steps: 1. crystal violet, the primary stain: followed by 1. crystal violet, the primary stain: followed by 2. iodine, which acts as a mordant by forming a crystal violet-iodine complex, then 2. iodine, which acts as a mordant by forming a crystal violet-iodine complex, then 3. alcohol, which decolorizes, followed by 3. alcohol, which decolorizes, followed by 4. safranin, the counterstain. 4. safranin, the counterstain.

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. 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. 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 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 gram- positive cell walls, closing the pores as the cell wall shrinks. Ethyl-alcohol will dehydrate the thicker gram- positive 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. For this reason, the diffusion of the crystal violet-safranin staining is inhibited, so the bacteria remain stained.