The Effects of fipronil on notochord development in

ZebrafishJoshua Mendoza-Elias

Biology 205L

Experiments in Developmental Biology

Fall 2006

Background on Fipronil

• Pesticide

• Blocks GABA receptors

• Teratogen

• Found to cause notochord damage in zebrafish --> Chordates

• GABA R active at 30 hours AEL

Stehr et al. 2006

Background-Accordian Phenotype

Question:• (i.) Early on, will exposure to Fipronil cause

neurodegeneration in notochord?• (ii.) Will the damage be necrotic tissue?• (iii.) Will their be damage elsewhere?

(i.) Fipronil damages notochord

(ii.) Damage will result in necrotic tissue

Hypothesis:

Materials & Methods

Control (0.1% acetone)

0.7 M Fipronil(0.1% acetone)

1.1 M Fipronil(0.1% acetone)

2.3 M Fipronil(0.1% acetone)

Notochord Morphology

Acridine Orange Staining

Behavioral Response

Results-Behavioral Response36 hrs - Control

36 hrs - 0.7 M

36 hrs - 1.1 M

36 hrs - 2.3 M

Results-Behavioral Response48 hrs - Control

48 hrs - 0.7 M

48 hrs - 1.1 M

48 hrs - 2.3 M

Results-Notochord MorphologyControl: 36 hrs, 48 hrs

36 hrs, 48 hrs - 0.7 M

36 hrs, 48 hrs - 1.1 M

36 hrs, 48 hrs – 2.3 M

Results

39Total moderate:

Total severe:

15Total WT:

7

Total moderate:

Total severe:

Total WT:

36 hrs

48 hrs

23

31

10

24.59%69.93%

11.47%

35.93%

48.43%15.62%

Results-Acridine Orange Staining

Discussion• Notochord damage first occurs

anteriorly

Higher concentration = more damage

Higher concentration = damage sooner

Exposure time = more damage

Future Directions

• Anti-body staining

• Examine upper notochord

• Circulation

References:

[1] Stehr. C., Linbo, L.L., Incardona, J. P, Scholz, N. L. 2006. The developmental neurotoxicity of fipronil: notochord degeneration and locomotor defects in zebrafish embryos and larvae. Toxicological Sciences. 2006 92 (1): 270 -278.

[2] Incardona, J., Stehr, C., Linbo, T., Scholz, N. Fipronil causes locomotor defects in developing zebrafish. 2006. Marine Environmental Research. 2006. 62: S74 -S75.

[3] Cole, Loretta M., Russel A. Nicholson, and John E. Casida. 1993. Action of phenylpyrazole insecticides at the GABA-gated chloride channel. Pest. Biochemical Physiology. 46: 47-54.

[4] Hamon, Nicholas, Richard Shaw, and Henry Yang. 1996. Worldwide development of fipronil insecticide. Proc.-Beltwide Cotton Conference. 2: 759-765.

[5] Colliot, F., K.A. Kukowskim P.W. Hawkins, and D.A. Robers. 1992. Fipronil: a new soil and foliar broad spectrum insecticide. Brighton Crop Proteonomics. Conf.-Pests Dis. 1:29-34.

Acknowledgements

• Dr. B

• Dr. P

• Nicole Roy

• Wendy Beane

• Monica Zhang