Lesson 1: Bacteria & Viruses YouTube Videos: Bozeman: Bacteria Bozeman: Archaea

All living organisms must carry out these biological functions: Movement (internal or external) Metabolism & Excretion Respiration Circulation Grow Reproduce Response

I. Introduction to Bacteria E. Coli O157:H7 can make you very sick. I. Introduction to Bacteria Very small (1-5 mm), single-celled, prokaryotic living organisms Were unknown until the development of the microscope Can be found on most materials and surfaces Billions on and in your body right now Streptococcus can cause strep throat. This E. coli helps you digest food. USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

A. Classifying Prokaryotes All are in kingdom Monera in the 5 Kingdom Classification System. Are classified as either Eubacteria or Archaebacteria in the 6 Kingdom System. Eubacteria Characteristics: Larger of the two, includes a wide variety of organisms, live almost everywhere. Usually surrounded by a cell wall made of the carbohydrate, peptidoglycan, which determines its shape and protects it. Ex: E. Coli

2) Archaebacteria Characteristics: Have cell walls that lack peptidoglycan, have membrane phospholipids that are different from the Eubacteria’s, and have genes that are more like those found in eukaryotic cells than in Eubacteria cells. Can live everywhere, including organisms, like you, extreme environments like in Utah’s Great Salt Lake, or in hot springs, geysers, deep ocean vents, etc.

B. Identifying Prokaryotes 4 ways are: by shape chemical nature of their cell walls the way they move how they obtain energy.

1) Shapes Three basic shapes Bacilli Three basic shapes Rod shaped called bacilli Round shaped called cocci Spiral shaped called spirilla Some exist as single cells, others cluster together Cocci Cluster of Cocci USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006 Spiral

2) Chemical Nature of Cell Wall Gram-staining is a method used to determine the type of cell wall. Gram-positive = have thick peptidoglycan cell walls & stain dark purple. Gram-negative = have thinner walls inside an outer lipid layer & stain pink or light red.

3) The way they move Some do not move. Some use flagella Some snake Some spiral forward Glide on slimy secretions

4) How they obtain energy? Photosynthetic bacteria Some make their own food from sunlight—like plants 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) They attack other living things Example: The bacteria on your face can attack skin causing infection and acne 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

Heterotrophs Chemoheterotrophs = take in organic molecules for energy and a supply of carbon. Photoheterotrophs = Use sunlight for energy but also need to take in organic compounds as a carbon source.

B. Autotrophs Photoautotrophs = use light energy to convert carbon dioxide and water to carbon compounds and oxygen. Chemoautotrophs = Make organic carbon molecules from carbon dioxide but use energy from chemical reactions involving ammonia, hydrogen sulfide, etc. instead of sunlight.

5) Respiration, Circulation & Excretion Uses the process of diffusion to carry out each process.

6. Growth & Reproduction Grow in number not in size Humans grow in size from child to adult 2 factors that limit growth in bacteria: Food availability & waste production USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006

Reproduce by Binary Fission In binary fission, the bacterium will double in size, replicate its DNA and then divide in half to make 2 bacteria (daughter cells). Bacteria reproduce exponentially.

Conjugation The process in which many bacteria exchange genetic information, increasing genetic diversity. A hollow bridge forms between 2 bacterial cells & genes move from 1 bacterium to the other.

Spore formation During unfavorable growth conditions, many bacteria form spores. Endospore = a type of spore formed by bacteria producing a thick internal wall around its DNA & part of its cytoplasm. These spores remain dormant until conditions become more favorable.

Lesson 3: Bacteria C. Bacteria: The Good, The Bad & The Ugly

. Importance of Bacteria Bacteria are vital to maintaining the living world. Some are: producers that capture energy some are decomposers some fix nitrogen (Ex: N2  NH3) some have other human uses (Ex: cleaning up oil spills, production of medications and food, production of vitamins in the human body, etc.)

A Closer Look – Helpful Bacteria www.bioweb.usu.edu Pediococcus - used in production of fermented meats Lactobacillus casei – found in human intestines and mouth to improve digestion Leuconostoc cremoris – used in the production of buttermilk and sour cream Lactobacillus bulgaricus – used in the production of yogurt

What is a pathogen? Bacteria that make you sick are pathogens. How do these bacteria 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 Direct or indirect Food, Water, or other Surfaces that are contaminated Not all bacteria are pathogens. Indirect contact Foods that could be contaminated USDA NIFSI Food Safety in the Classroom© University of Tennessee, Knoxville 2006 Direct contact

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

What are some common pathogens? E. coli O157:H7 Pathogenic E. coli (like O157:H7) Found in ground beef, contaminated fruits and vegetables Salmonella Found in raw meats, poultry, eggs, sprouts, fruit and vegetables Listeria Found in deli foods, lunch meats, smoked fish and vegetables Salmonella Listeria

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

How can I avoid pathogens? 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

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

Stained Bacteria Cells at 4x

Stained Bacteria Cells at 10x

Stained Bacteria Cells at 40x

Lesson 2: Viruses YouTube Videos Bozeman: Viruses Flu Attack! How a Virus Invades Your Body

II. Viruses What is a virus? Virus = particles of nucleic acid, protein, and in some cases, lipids. Wendell Stanley obtained crystals of tobacco mosaic virus. Since living organisms do not crystallize, he determined that viruses are not alive.

Viruses are also not considered alive because they are incapable of reproducing themselves. They infect living cells and the cells reproduce them. A typical virus is composed of a core of DNA or RNA surrounded by a protein coat.

capsid = a virus’s protein coat. Has proteins that enable the virus to enter a host cell. The cell then translates the viral genetic information into capsid proteins. The cell transcribes and translates the viral genetic information. Sometimes the cell makes copies of the virus, thus killing the host cell.

Most viruses are specific to the type of cell they infect. Ex: Bacteriophage viruses only infect bacteria.

B. Viral Infection Once inside the cell, one of two different processes can occur. Lytic Infection = destroys the host cell immediately. A virus enters a cell, the cell makes copies of the virus, and causes the cell to burst.

Lysogenic Infection = the host cell continues to make copies of the viruses. A virus integrates its DNA into the DNA of the host cell and the viral genetic information replicates along with the host cell’s DNA. Eventually, the host cell will burst.

Retroviruses HIV Virus Replication 3D Video Retroviruses = viruses contain RNA as their genetic information. Their genetic information is copied backwards: RNA to DNA Ex: HIV (Human Immunodeficiency Virus) HIV Virus Replication 3D Video

HIV invasion of a T-cell