Affect of heavy metal induced oxidative stress tolerance on energy metabolism in Drosophila

melanogaster

Geetanjali SageenaEvolutionary Biology Laboratory

Department of Zoology University of Delhi New Delhi-110007

Industrialization and urbanization has resulted in environmental pollution.

Various Heavy metals are adding to environmental load due to higher rate of persistence and accumulation.

Results in oxidative stress. Persistent imbalance between antioxidants and pro-oxidants causing irreversible cellular damage.

Adaptive physiological mechanisms aid in increased survival which plays an important role in evolution and adaptation of living organisms.

Background

www.anatomy.unimelb.edu.au/.../life_cycle.jpg

22-24 h

~ 24 h

~ 24 h~ 48 h

~ 11

0 h

Fly maintenance

Pre Adult Duration 9½ days Lifespan 30 Days

Pre Adult Duration 7 days Lifespan 45 Days

Control• Resource Rich• Short Lifespan

Selected•Resource Deficient•Long Lifespan

Adult flies are housed in Plexiglas cages (25 x 20 x 15 cm3) Banana-jaggery food is provided in petridish and changed every alternate day. Populations kept at standard laboratory conditions (SLC).

To check the effect/affect of two chemical stressors (Heavy Metals) namely FeSO4 and CdCl2 on L1 to adult development.

Estimation of major energy reserves in both stressed and non stressed condition

Aims and Objectives

Two types of fly populations

Heavy Metal Conc.

MethodologyCONTROL (JBs)

SELECTED (FLJs)

SM

SM + 13 mM FeSO4

SM + 5µM CdCl2

1

2

3

4

YEAST

Sync Eggs

L1 to adult development time.Estimation of major energy reserves i.e. Lipids,

Proteins and Carbohydrates by Ether, BCA and Anthrone method respectively

Estimation of Energy accumulation per unit time.

(Platt and Irwin 1973)

RESULTSdevelopmental Time

Lipid content

PROTEIN content

carbohydrates content

energy accumulation/ time

Treatment F2,4 = 16.107, p = 0.01

Larval growth slowed when reared on heavy metal supplemented diet.

Increased development time did not result in the increased macromolecular accumulation among the flies. Slowing down of the metabolic processes, or a greater utilization of energy reserves during metamorphosis or both.

Bioenergetics play a crucial role in regulation of Oxidative stress. Positive relation between energy reserve and stress tolerance. Whereas

stress tolerance and lifespan are not tightly correlated.

Females more tolerant than males.

CONCLUSIONS

Acknowledgements My Supervisor Dr. Mallikarjun Shakarad

Funding agency CSIR &DU

Experimental Work: Mr. Rakesh Roshan

Ms Shreya Choudhary

Ms Nalini Mishra

Laboratory Assistance: Sahil Malhotra