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December 13, 2011

NES: Ultraviolet Radiation and Yeast: Radiation Biology

Presented by: Alissa Keil

Ultraviolet Radiation and Ultraviolet Radiation and Yeast: Radiation BiologyYeast: Radiation Biology

Ultraviolet Radiation and Ultraviolet Radiation and Yeast: Radiation BiologyYeast: Radiation Biology

Alissa KeilAlissa Keil

NES Education SpecialistNES Education Specialist

Oklahoma State UniversityOklahoma State University

NASA Johnson Space CenterNASA Johnson Space Center

Have you used classroom Have you used classroom lessons from NASA?lessons from NASA?

Have you used classroom Have you used classroom lessons from NASA?lessons from NASA?

√√ YesYesXX No No

Ultraviolet Radiation and Yeast: Ultraviolet Radiation and Yeast: Radiation Biology OverviewRadiation Biology Overview

• Radiation Biology Educator Guide Radiation Biology Educator Guide http://er.jsc.nasa.gov/seh/RB_Modulehttp://er.jsc.nasa.gov/seh/RB_Module_2_11.pdf_2_11.pdf

• Space radiation’s importance to Space radiation’s importance to NASANASA

• Most effective method for preventing Most effective method for preventing UV damage in yeastUV damage in yeast

• Discussion questions for labDiscussion questions for lab

• Extensions for classroomExtensions for classroom

Subject AreasSubject Areas

Grade Level:

9-12

Subject Area:

Biology

National StandardsNational Standards• Life Science

– Matter, energy an organization in living systemsScience in personal and social perspectivesNatural and induced hazards

Learning ObjectivesLearning Objectives

Students will be able to:Students will be able to:•Discuss the counter measures for UV radiationDiscuss the counter measures for UV radiation•Describe phenotypic changes in yeast as a result of Describe phenotypic changes in yeast as a result of radiation damageradiation damage

ISS Tissue Equivalent Proportional Counter

MisconceptionsMisconceptions

What are some misconceptions What are some misconceptions students may have about radiation?students may have about radiation?

Type some ideas in the chat window.Type some ideas in the chat window.

• Understand that DNA contains the instructions for proper cell function

• DNA can be changed• Skin cancer and other adverse health effects can be

caused by exposure to ultraviolet (UV) radiation• Sun protection factor (SPF) ratings on sunscreens

What do students need to know?

Questions?Questions?

IntroductionIntroduction

What is radiation?What is radiation?

• Form of energy that is transmitted in the form of rays, electromagnetic waves, and/or particles

• Daily life – cell phones, microwaves , X-rays, light bulbs, heaters

• Natural – sun, radioactive elements in the Earth’s crust

Radiation TypesRadiation TypesNon-ionizing IonizingNon-ionizing Ionizing

How is radiation measured?How is radiation measured?

Risks and SymptomsRisks and Symptoms• The biological effects of The biological effects of

exposure vary with the dose.exposure vary with the dose.

What are the risks and symptoms What are the risks and symptoms of radiation exposure?of radiation exposure?

Radioactive radon gas produced from the breakdown of uranium in the Earth’s crust accounts for over half of the radiation exposure to the general public.

How does radiation affect us?How does radiation affect us?

Questions?Questions?

NASA NASA ConnectionConnection

Radiation Biology

Radiation Biology? Radiation Biology?

Why is NASA studying biological Why is NASA studying biological effects of radiation?effects of radiation?

• Keep astronauts safe

• Identify health risks• Work to understand

damage• Develop

countermeasures

How do scientists study biological How do scientists study biological change during spaceflight?change during spaceflight?

• Scientists develop space biology experiments

– in flight experiment

– ground control• Analyze both to

understand biological changes

Using non-human organisms to Using non-human organisms to understand radiation damageunderstand radiation damage

• Study model organisms

• Small in size – large numbers studied in smaller volume

• Fruit flies – many things in common with humans

Why does NASA Why does NASA study yeast in space?study yeast in space?

• NASA uses yeast as a model NASA uses yeast as a model system to explore the effects of system to explore the effects of radiation on cells. Just like radiation on cells. Just like human cells, most yeast cells human cells, most yeast cells effectively repair DNA damage effectively repair DNA damage caused by radiation. caused by radiation.

What is DNA?What is DNA?

What is DNA’s role in What is DNA’s role in protein production?protein production?

DNA is the storage unit for the information used to make proteins.

What kinds of damage occur due What kinds of damage occur due to radiation?to radiation?

• Single strand break, or SSBSingle strand break, or SSB

• Double strand break, or DSBDouble strand break, or DSB

Kinds of Damage, continuedKinds of Damage, continued

• Not immediately Not immediately observableobservable

• Some damage may not Some damage may not show up until much latershow up until much later

What kinds of damage can high What kinds of damage can high energy ions cause?energy ions cause?

• Not immediately observableNot immediately observable• Some damage may not show Some damage may not show

up until much laterup until much later

Harm to DNAHarm to DNA

Earth’s ProtectionEarth’s Protection

• Magnetic fieldsMagnetic fields• AtmosphereAtmosphere

Protection from RadiationProtection from Radiation

Radiation Countermeasures:Radiation Countermeasures:-Radiation DosimetryRadiation Dosimetry-Operational Operational

Protection from Radiation, cont.Protection from Radiation, cont.

• DietaryDietary• EngineeringEngineering

Radiation Re-cap…Radiation Re-cap…

What is radiation dosimetry?What is radiation dosimetry?

AA. Drugs ingested to reduce radiation effects. Drugs ingested to reduce radiation effects

B. MB. Monitoring, characterizing, and quantifying the radiation environment where astronauts live and work

C. Gamma rays and cosmic raysC. Gamma rays and cosmic rays

D. I don’t rememberD. I don’t remember

Questions?Questions?

Long Term Space TravelLong Term Space Travel• Monitoring and Monitoring and

collecting collecting radiation doses radiation doses received by received by astronauts for astronauts for yearsyears

• Effects poorly Effects poorly understoodunderstood

NASA ResearchNASA Research

Materials on International Space Station Experiment-8

Intra-Vehicular Charged Particle Directional Spectrometer

Radiation Area Monitor

Extra-Vehicular Charged Particle Directional Spectrometer

Radiation FactorsRadiation Factors

• AltitudeAltitude

• Solar CycleSolar Cycle

• Astronaut’s Astronaut’s susceptibility susceptibility

NASA Radiation LabNASA Radiation Labhttp://www.bnl.gov/medical/nasa/http://www.bnl.gov/medical/nasa/

LTSF.aspLTSF.asp

Courtesy of Brookhaven National Laboratory

Lesson in DetailLesson in DetailRadiation Biology

Materials for LessonMaterials for Lesson1. Yeast-Extract Dextrose media plates (from kit, can also be made)2. UV-sensitive yeast suspension in liquid media and wild type yeast suspension in liquid media 3. A source of UV radiation such as direct sunlight 4. Several kinds of sunscreen (each with different SPF), black paper, cloth, metal foil, or other types of materials that can be used to experiment with UV shielding5. Sterile water, sterile pipettes, and sterile toothpicks6. Plastic wrap (to cover plates)

Procedures Procedures 1. Ensure that your hands and

the work area are clean.2. Plate the yeast suspension.3. Label the dish by drawing

lines on the top and bottom of the dish to divide it into 4 parts.

4. Spread sunscreen on the lid of the Petri dish (or on the plastic wrap) in the places you marked; use an equal amount in each section and spread the sunscreen evenly. You can also use plastic, foil, etc. instead of sunscreen.

Procedures, continuedProcedures, continued

5. Expose Petri dish to sun or to UV light. 6. After the exposure, wipe the sunscreen off the lid of the Petri dish. Place the Petri dish upside down in an incubator or in a dark place; let it grow for 1-2 days in an incubator at 30°C or 3-4 days at room temperature.7. If desired, repeat these steps with a wild type strain as a control for comparison.8. Compare the amount of yeast that has grown in different areas of the Petri dishand draw conclusions.

How will you quantify results?How will you quantify results?

•Count the colonies •Determine if there was difference in SPF•Calculate survival levels for SPF•Look for mutations in yeast

EngagementEngagement

• Introduce video to studentsIntroduce video to students• Generate discussionGenerate discussion• Why radiation biology?Why radiation biology?• UV radiation: How it affects life on UV radiation: How it affects life on

Earth?Earth?• Stimulate interest with the NASA Stimulate interest with the NASA

connectionconnection

Discussion QuestionsDiscussion Questions

• What are the effects of different types of What are the effects of different types of sunscreen on yeast?sunscreen on yeast?

• How can health be affected by exposure to How can health be affected by exposure to ultraviolet radiation?ultraviolet radiation?

• Why use yeast to study the effects of UV Why use yeast to study the effects of UV radiation?radiation?

• Does yeast grow less in some areas? More in Does yeast grow less in some areas? More in others? Why?others? Why?

• Did some sunscreens protect the yeast Did some sunscreens protect the yeast better than others?better than others?

• Does the UV pass through plastic wrap or Does the UV pass through plastic wrap or petri dish covers?petri dish covers?

• What can you conclude from the results of What can you conclude from the results of your experiment?your experiment?

Discussion Questions

Extensions and Extensions and ResourcesResources

Ultraviolet Radiation and Yeast: Radiation Biology

ExtensionsExtensions

• Make several plates with diluted yeast cultures and expose the yeast to sunlight at various times of day - every 2 hours. You can use the same period of exposure.

• Expose the yeast for different durations at the same time of day, for example 0, 0.5, 1, 2, 4, and 8 minutes at a certain time.

ExtensionsExtensions

• Compare the different types of yeast strains for UV sensitivity. Obtain wild-type S. cerevisiae and culture this strain then plate out dilutions. Compare the sensitivity of the two to ultraviolet light from the sun.

Other topics you can cover…Other topics you can cover…

• What are the consequences of DNA damage?• What is the DNA repair system?• How does UV radiation affect us?• What is degenerative tissue damage?

More Advanced ExperimentsMore Advanced Experiments

• Using Yeast to Measure the Intensity of Solar Ultraviolet Radiation

http://www.phys .ksu.edu/gene/d3.html

• Space Faring: The Radiation Challengehttp://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/Space_Faring_Radiation.html

Something to think about…Something to think about… Each individual astronaut has

agreed to be exposed to this extra radiation, knowing that space travel for now cannot

avoid it.

Why do you think they would be willing to do this?

Type your thoughts into the chat box.

Questions?Questions?

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