The Effect of Caffeine on the Resistance to Heat in Drosophila melanogaster

Richard Niederecker, Kara Kirkpatrick, Samyar Attarian

Department of Biology SciencesSaddleback College

28000 Marguerite Parkway, Mission Viejo, CA 92692

Introduction• Drosophila melanogaster– Fruit fly

• Research benefits:– Short Lifespan– Distinct Developmental stages– Similarities to humans• Genome• Heat shock response

Lanneau, D., M. Brunet, E. Frisan, E. Solary, M. Fontenay, and C. Garrido. 2008. "Heat shock proteins: essential proteins for apoptosis regulation". Journal of Cellular and Molecular Medicine. 12 (3): 743-761.

Heat Shock Proteins (HSPs)• Historically drosophila cells

have been used to study heat shock proteins

• Protective function– Renature proteins

• Dependent Chaperone proteins– ATP

Example of Heat Shock Protein

Tissieres, A., Mitchell, H. K., and Tracy, U. (1974) Heat Shock Proteins: from Bacteria to Man, Cold Spring Proteins: from Bacteria to Man, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY. J. Mol. Bio. pg. 84, 389Beissinger, M., & Buchner, J. (1998). How chaperones fold proteins. Biol Chem, 379(3):245-59. http://www.ncbi.nlm.nih.gov/pubmed/9563819.Image by Jawahar Swaminathan and MSD staff at the European Bioinformatics Institute - http://www.ebi.ac.uk/pdbe-srv/view/images/entry/3hsc600.png, displayed on http://www.ebi.ac.uk/pdbe-srv/view/entry/3hsc/summary

Heat Shock Factors (HSFs)• Active HSFs bind to DNA to

stimulate production of HSPs• Monomer to Trimer• Trimer- active form• Trimer binds to DNA

Liou, S. (2010). The Heat-Shock Response. Miscellaneous Drugs. Huntington's Outreach Project for Education, at Sanford. Web. <http://web.stanford.edu/group/hopes/cgi-bin/hopes_test/the-heat-shock-response/>.

InducersNormal Cell Conditions(low concentration HSPs)

• Embryonic development• Hormonal stimulation• Cell differentiation• Cell cycle

– Cancer research

External Stressors (higher concentration HSPs)

• Oxidants• Heavy metals• Infectious diseases• Heat • Caffeine

• The Effect of Heat and Caffeine on the Development of Fruit Flies (Drosophila melanogaster) by Shiffman and Soliman (2014)

Shiffman, B. & Soliman, K. (2014). The Effect of Heat and Caffeine on the Development of Fruit Flies (Drosophila melanogaster). Department of Biological Sciences Saddleback College.

HypothesisDrosophila melanogaster consumption of caffeine will induce the production of HSPs, extending the lifespan of the flies in heat compared to heat alone.

Methods and Materials• 3 colonies– 120 flies each– Control and test

groups• Control groups

standard medium• Test groups

caffeinated medium• Incubated at 32C

• Medium production

Methods and Materials

• Two analyses – Pupae (1st colony)– Larvae (2nd and 3rd colonies)

• Extended caffeine exposure

• Incubated for full lifespan• Medium rehydrated

frequently– Increased caffeine

concentration– Dehydration of flies

One-tailed unpaired t-testp = 0.0047

Caffeinated Non-caffeinated0

1

2

3

4

5

6

7

8

9Pupa to Adult Lifespan

Fly Groups

Life

span

(day

s)

Caffeinated Non-caffeinated0

1

2

3

4

5

6

Larva to Pupa Lifespan

Fly Groups

Life

Spa

n (d

ays)

One-tailed unpaired t-testp = 1.45 x 10-13

Discussion and Conclusion

• Hypothesis rejected for all colonies

• Caffeine and heat are independent stressors

• Caffeine toxicity and heat• Conditioning

Muller, P. & Vernikos-Danellis , J. (1969). Effect of Environmental Temperature on the Toxicity of Caffeine and Dextroamphetamine in Mice. The Journal of Pharmacology and Experimental Therapeutics. Vol. 171 no 1 pg. 153-158Krebs, R. A., & Loeschcke, V. (1994). Costs and Benefits of Activation of the Heat-Shock Response in Drosophila melanogaster. Functional Ecology, 8(6), 730–737. http://doi.org/10.2307/2390232

Acknowledgements

Steve TehTony Huntley