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)

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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.

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Bacterial Shapes and Grouping Patterns

Individual Shapes

Grouping Patterns

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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.

http://learn.genetics.utah.edu/content/cells/scale/

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StreptococcusStrep throatIf the infection gets

into the blood stream it could cause life threatening conditions

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Methicillin-resistant Staphyloccus aureus (MRSA)

Skin infectionsResistant to

antibiotic medication

In medical facilities, causes life-threatening blood infections, pneumonia and surgical site infections.

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Lyme borreliosisTransmitted by an

infected tick

Causes fatigue, chills, fever, headache, muscle and joint aches, and swollen lymph nodes

If left untreated, neurological damage may occur

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Escherichia coli

Harmless version is found in your intestines and helps digestion.

Harmful version will cause food poisoning.

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Benefits of BacteriaNutrient 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.

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Benefits of BacteriaProbiotics (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.

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Benefits of BacteriaFood

Bacteria can be used to help manufacture certain foods:

CheeseYogurtPicklesChocolate?!

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Benefits of BacteriaMedicine

Bacteria can be genetically modified to make medicine (ex. insulin)

Some antibiotics are made with bacteria:

StreptomycinBacitracinTetracyclineVancomycin

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Treatments for Bacterial Infections

ANTIBIOTIC DRUGS: chemicals produced artificially ornaturally 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

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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.

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How Antibiotic Resistance Occurs…

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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.

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Structure of VirusesViruses 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

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PoliovirusTransmitted 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.

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EbolaTransmitted by

bodily fluids.

90% of patients die.

Bleeding from the eyes is a late symptom of the disease.

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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.

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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.

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Viral Replication

Viruses need a host cell in order to replicate.

1. LYTIC CYCLEactive infection

InfluenzaCommon Cold

2. LYSOGENIC CYCLEdormant infection

Herepes

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www.youtube.com/watch?v=Rpj0emEGShQ

Treatment for Viral InfectionsANTIRETROVIRAL 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.

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https://www.youtube.com/watch?v=GYuI6oGiZfA

• 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

VIRUS BACTERIA14

Non-Specific Immune Response

1st and 2nd lines of defense are non-specific. This type of defense protects the body from any

pathogen that the body encounters.

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1st Line of Defense (Non-Specific)

PHYSICAL BARRIER: skin & cilia

CHEMICAL BARRIER: saliva, tears, nasal secretions, & hydrochloric stomach acid

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2nd 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.

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Specific Immune ResponseThe 3rd line of defense that targets & attacks

specific pathogens that pass through the 1st and 2nd lines of defense. It is more effective, but takes time to develop.

http://glencoe.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::550::400::/sites/dl/free/0078802849/383924/Ch37.swf::Visualizing%20Specific%20Immune%20Responses

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ANTIGEN (pathogen) enters the body & has passed the 1st and 2nd 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.

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FINAL STEPYour 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.

AntibodiesANTIBODIES:

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

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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. Vaccine Grade

DTaP (Diptheria, Tetanus, acellular Pertusis)

pre-Kindergarten

Polio pre-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

Meningitis College

Flu - Influenza (seasonal)

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