Effects of Benzene on Brine Shrimp, Artemia franciscana

1. Effects of Benzene on Brine Shrimp, Artemia franciscana Kendall Asper (Dr. Nicole Okazaki), Spring 2008 Weber State University, Department of Zoology; Ogden, UT 84408 • Figure 3: Number of Broods However, the shrimp were exposed for only 24 hours to the TCB and their life parameters were subsequently observed (Grosch, 1973). Crude oils, in concentrations ranging in the part per thousand, killed most shrimp within three hours (Trieff, 1980).  These crude oils contain many toxic compounds, with benzene among them.   Benzene has wide ranging effects in cells, triggering genotypic damage resulting in leukemias and other types of cancers (Medlin, 2003).  While the SDS-PAGE study does not identify which proteins are affected, it points to changes occurring in the cells.  Some of the proteins affected might be the heat-shock proteins 70 and 90. Results • Acute exposure: While only 1.1% of larvae died in the control, the mortality rates were 30.1% and 4.0% after exposure to 10-3 and 10-2 (v/v) benzene solutions, respectively. • 24 hr. acute exposure to benzene solution of 10-2 (v/v) was 50.0% fatal to adult shrimp while all survived in 10-3 (v/v) benzene solution and in the control. • SDS-PAGE showed an increasing expression of some proteins with increasing benzene concentration (see Figure 1). • Western Blot showed increasing expression of proteins with an affinity to antibodies used to identify heat shock proteins (see Figure 2). • Mean time to maturation for brine shrimp were 27.8 days for controls, 29.4 days for 10-5 (v/v) benzene solutions, and 29.6 days for 10-4 (v/v) benzene solutions. Number of Broods Introduction The Great Salt Lake is a terminal lake highly susceptible to contamination . Benzene, a volatile organic compound (VOC) and waste product of crude oil distillation, has been detected in water near residential and commercial areas surrounding Salt Lake City (Thiros, 2000). This experiment was designed to determine the physiological effects of benzene on one of the Great Salt Lake’s native species, Artemia franciscana. • Figure 4: Mean number of cysts/larvae per brood: Figure 1: SDS-PAGE; proteins taken from adult brine shrimp exposed to benzene for 24 hrs. Lanes furthest left and right are protein ladders. Benzene concentrations are from left to right as follows: Control, 10-6, 10-5, 10-4, 10-3, 10-2. Discussion Methods Under short term laboratory exposure, Artemia larvae and adults have a high tolerance to benzene, with mortality occurring at high concentrations of 10-2 and 10-3 (v/v). Under chronic exposures of 10-4 and 10-5 (v/v) the maturation time was not affected; the number of shrimp that reached maturation, especially the females, were dramatically decreased.  The presence of benzene appears to have a direct and proportional deleterious effect on the number of eggs produced per brood. Very few studies about the effect of benzene on Artemia have been found.  Similarly to our study, exposure to a derivative of benzene, TCB, increases mortality, especially in females, and sharply reduces the number of eggs.  Literature Cited • Acute exposure: Survival of adult and larval Artemia were observed after 24 hour exposure to 3% seawater (SW) solutions containing benzene concentrations ranging from 10-2 to 10-8 (v/v). • The level of expression of heat shock proteins hsp70 and hsp90 were visualized in adult shrimp exposed to sub-lethal doses of benzene, 10-4 and 10-5 (v/v), for 24 hours, using SDS-PAGE and Western Blot assays. Grosch, Daniel S. 1973. Reproduction Tests: The Toxicity for Artemia of Derivatives from Non-Persistent Pesticides. Biol. Bull. 145:340-351. Thiros, Susan A. 2000. Quality of Shallow Ground Water in Areas of Recent Residential and Commercial Development in Salt Lake Valley, Utah, 1999. USGS Fact Sheet FS-106-00. Medlin, J.  2003. Benzene adverse effects: microarrays reveal breadth of toxicity.  Environmental Health perspectives, 111(11): 590-591. Trieff. N.M.  1980.  Toxicity of heavy metals, oils and other organics on Artemia. in. The Brine Shrimp Artemia, Vol. 1.  Morphology, genetics, Radiobiology, Toxicology. G.Persoone, P. Sorgellos, O. Roels, and E. Jaspers (Eds). Universa Press, Wetteren, Belgium, p:253-263.  Figure 2: Western Blot; the image to the left was treated with hsp70 antibodies and the image to the right was treated with hsp90 antibodies. The lanes, from right to left, are the ladder control, 10-6, 10-5, 10-4, 10-3, 10-2. • Chronic exposure: The effect of benzene concentrations of 10-4 and 10-5 (v/v) on the maturation rate and fertility was measured. For each treatment, seventy larvae were raised in 50 ml benzene solutions of 3% SW with algae. Acknowledgements A special thanks to the Office of Undergraduate Research for this opportunity.