Microbiology

General Structure of a Bacteria Cell Plasmid DNA: small circular DNA that is separate from the rest of the bacteria’s genome Nucleioid DNA: large circular DNA found in the nucleiod region. Provides instructions for critical life functions. Capsule: a layer of polysaccarides; provides extra protection for the cell and helps prevent drying out Pila: helps the cell attach to surfaces Flagellum: helps the cell move WHAT IS LACKING FROM A BACTERIA CELL? Cell Wall: made of peptidglycans (polymer consisting of sugars and amino acids) 1

Bacterial Reproduction BINARY FISSION: the division of a cell into two genetically identical cells. A form of asexual reproduction. If the conditions are just right, one bacterium could become one billion bacteria in just ten hours. 2

Bacterial Shapes and Grouping Patterns Individual Shapes   Grouping Patterns 3

Diplococcus

Spirillum volutans

Streptococcus pneumoniae

Lactobacillus acidophilus

Staphylococcus aureus

Size of Bacteria Cells Bacteria cells are smaller than eukaryotic cells. Bacteria cells are larger than viruses. 4

Streptococcus Strep throat If the infection gets into the blood stream it could cause life threatening conditions 5

Methicillin-resistant Staphyloccus aureus (MRSA) Skin infections Resistant to antibiotic medication In medical facilities, causes life-threatening blood infections, pneumonia and surgical site infections. 5

Lyme borreliosis Transmitted by an infected tick Causes fatigue, chills, fever, headache, muscle and joint aches, and swollen lymph nodes If left untreated, neurological damage may occur 5

Escherichia coli Harmless version is found in your intestines and helps digestion. Harmful version will cause food poisoning. 5

Benefits of Bacteria Nutrient Cycling Bacteria are decomposers, returning nutrients like carbon and phosphate to the environment Nitrogen gas cannot be absorbed by plants. Nitrogen-fixing bacteria convert the nitrogen gas into compounds that plants can use. Nitrogen is important for the making of DNA, RNA and amino acids. 6

Benefits of Bacteria Probiotics (Flora) Bacteria that live inside organisms that help promote healthy digestion & reduce growth of harmful bacteria. E.coli and humans have a symbiotic relationship: E.coli provide Vitamin K and humans provide a “home” for the bacteria to live in. 6

Benefits of Bacteria Food Bacteria can be used to help manufacture certain foods: Cheese Yogurt Pickles Chocolate?! 6

Benefits of Bacteria Medicine Bacteria can be genetically modified to make medicine (ex. insulin) Some antibiotics are made with bacteria: Streptomycin Bacitracin Tetracycline Vancomycin 6

Treatments for Bacterial Infections ANTIBIOTIC DRUGS: chemicals produced artificially or naturally by other microbes that kill SPECIFIC bacteria by 4 possible methods: 1. Damages cell walls  2. Damages cell membrane  3. Inhibits gene copying  4. Inhibits protein synthesis  7 prevents synthesis of new cells cell will rupture prevents DNA replication and transcription (DNA to RNA) prevents RNA to proteins, enzymes for metabolic activity is stopped

Overuse and Misuse of Antibiotics OVERUSE: 1. Someone takes old antibiotics or was someone else’s prescription. 2. Excessive use of antibacterial soap and cleaning products. 3. Livestock feed includes antibiotics. MISUSE: 1. A doctor prescribes a patient antibiotics when they have a viral infection instead. Viruses are not affected by antibiotics (no cell wall, cell membrane or enzymes to act upon). 2. The patient skips dosages of the prescription. 8

How Antibiotic Resistance Occurs… 9

Strategies to Prevent Antibiotic Resistance Patients Can: Take an antibiotic exactly as the healthcare provider tells you. Don’t pressure your doctor for antibiotics. Speak out. Urge Congress to fund more research into antibiotic resistance and alternatives to antibiotics. Healthcare Providers Can: Include microbial cultures before deciding what to do. Keep track of antibiotic outbreaks in hospitals. Develop prevention and control programs. 9

Structure of Viruses Viruses are a non-living structures that come in various shapes. All viruses have the following 2 things: 1. Genetic Material: DNA or RNA 2. Capsid: the outer layer of the virus made of protein 10

Poliovirus Transmitted by fecal matter or saliva. 90% patients don’t show symptoms, if the virus invades the nervous system it will cause paralysis. Polio is almost eradicated around the world. 11

Ebola Transmitted by bodily fluids. 90% of patients die. Bleeding from the eyes is a late symptom of the disease. 11

Common Cold Transmitted by airborne droplets or nasal secretions. Could be caused by 1 of more than 100 types of viruses. Treatments only provide symptomatic relief. 11

HIV The following body fluids can contain high levels of HIV: blood pre-seminal and seminal fluids vaginal fluids breast milk Attacks and destroys human immune cells called T-cells. When T-cell counts are extremely low, the person is diagnosed with AIDS. 11

Viral Replication Viruses need a host cell in order to replicate. 1. LYTIC CYCLE active infection Influenza Common Cold 2. LYSOGENIC CYCLE dormant infection Herepes 12

Treatment for Viral Infections ANTIRETROVIRAL DRUGS: Designed specifically to target certain viruses. Disables the proteins on the capsid of the virus and inhibits further development. If the virus mutates the drug is no longer effective. 13

Non-living Not made of a cell Capsid (for protection) DNA RNA Sometimes causes diseases Needs a host to replicate Does not need a host to replicate Made of a cell Living Capsule (for protection) Can mutate & become resistant to medications Binary fission Lytic Cycle (active) Lysogenic Cycle (dormant) Antiretroviral drugs Antibiotic drugs Smaller than a bacterium Larger than a virus VIRUSBACTERIA 14

Non-Specific Immune Response 1 st and 2 nd lines of defense are non-specific. This type of defense protects the body from any pathogen that the body encounters. 15

1 st Line of Defense (Non-Specific) PHYSICAL BARRIER: skin & cilia CHEMICAL BARRIER: saliva, tears, nasal secretions, & hydrochloric stomach acid 15

2 nd Line of Defense (Non-Specific) INFLAMATION – increase in body temperature & flow of liquids in the body MACROPHAGES – type of WBC that engulf s pathogens, enzymes inside the cell digest it. 15

Specific Immune Response The 3 rd line of defense that targets & attacks specific pathogens that pass through the 1 st and 2 nd lines of defense. It is more effective, but takes time to develop. c%20Immune%20Responsesglencoe.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf 15

ANTIGEN (pathogen) enters the body & has passed the 1 st and 2 nd lines of defense MACROPHAGE engulfs & places a portion of the antigen outside the cell Macrophage activates the HELPER T-Cell by presenting the antigen. Helper T-cell binds to a B-CELL. The B-cell will now produce ANTIBODIES. Helper T-cell binds to a CYTOTOXIC T-Cell. This cell will bind to and kill infected cells with the known pathogen. ANTIBODIES attach to the now known pathogen. Cytotoxic T-cells will attack the marked target. 16

FINAL STEP Your immune system will now replicate the B & T memory cells that just learned how to recognize the pathogen. You immune system will be better prepared the next time that particular antigen invades your body.

Antibodies ANTIBODIES: Y-shaped proteins produced by B-cells. Attach to a specific antigen to promote an immune response. If the antigen has mutated, then antibodies may not recognize it. Anti 17

Vaccination Deliberate exposure of the body to an antigen so that a specific immune response can develop. Vaccines contain killed or weakened pathogens, which are incapable of causing the disease. VaccineGrade DTaP (Diptheria, Tetanus, acellular Pertusis)pre-Kindergarten Poliopre-Kindergarten Hep B (Hepatitus B)pre- Kindergarten, Middle School MMR (Measles, Mumps, Rubella)pre- Kindergarten, Middle School VAR (Varicella)pre-Kindergarten, Middle School HPV (Human Papillomavirus)Middle School MeningitisCollege Flu - Influenza(seasonal) 18