Post on 31-Jan-2016
description
Pam Clarkson
Effects of atrazine on thyroid hormone induction of metamorphosis in the axolotl (Ambystoma mexicanum)
Xenopus laevis Hayes et al, 2002, PNAS
-- Post application (Spring) runoff can be > 20 ppb
-- typical surface and groundwater concentrations at other times during other times of the year, 0.001 to 1.0 ppb
-- 3 ppb EPA standard for drinking water
ATRAZINE
ENDOCRINE DISRUPTION
Males exposed to 0.1 ppb have lowered testosterone, elevated estrogen, and intersex gonads
Introduction• Thyroid hormones induce metamorphosis
in the axolotl• We investigate affects of atrazine on TH-
induction of metamorphosis in the axolotl• We investigate affects of atrazine on
growth
Big PictureTo begin characterization of gene expression
during salamander metamorphosisHypothesis: no variation in gene expression during metamorphosis
For comparison to endocrine disrupted
metamorphosis
To identify loci that will be useful in field diagnostics of normal and endocrine disrupted metamorphosis
To correlate patterns of gene expression with morphological, developmental, and life history malformations during endocrine disruption
metamorphosis
paedomorphosis
Page et al., 2007
- Effect of atrazine on growth
- Confirm standrard TH-induction
- Effect of atrazine on metamorphosis
Results Summary
0
10
20
30
40
50
60
70
80
1 2 3
atrazine (ug/L)
pre
-TH
mass (
g)
86
88
90
92
94
96
98
1 2 3
atrazine (ug/L)
post-
TH
len
gth
(m
m S
VL)
0
2
4
6
8
10
12
14
16
1 2 3
atrazine (ug/L)
gil
l le
ng
th (
mm
)
108
110
112
114
116
118
120
122
124
126
128
1 2 3
atrazine (ug/L)
fin
len
gth
(m
m)
pre
-TH
mas
s (g
)
po
st-T
H l
eng
th (
mm
SV
L)
gil
l le
ng
th (
mm
)
fin
len
gth
(m
m)
07
35 0 7
0
35
0 357 7 35
)
)
)
)
40
42
44
46
48
50
52
54
56
58
1 2 3
TH (nM)
pre
-TH
mass (
g)
87
88
89
90
91
92
93
94
95
96
97
1 2 3
TH (nM)
post-
TH
len
gth
(m
m S
VL)
6
7
8
9
10
11
12
13
14
15
1 2 3
TH (nM)
gil
l le
ng
th (
mm
)
100
105
110
115
120
125
130
135
1 2 3
TH (nM)
fin
len
gth
(m
m)
pre
-TH
mas
s (g
)
po
st-T
H l
eng
th (
mm
SV
L)
gil
l le
ng
th (
mm
)
fin
len
gth
(m
m)
0 550
550
0
0 5 50 05
50
ACKNOWLEDGMENTS
Chris Beachy (MSU)Heather Modrow (MSU)Leah Crites (MSU)Charles Crites (MSU)Amanda Lafountain (MSU)Sharon Denks (FBCC)Dwight Blackhawk (FBCC)Erica Goodbear (FBCC)Janel Richter (MSU)Heather Modrow (MSU)Claude Ouedraego (MSU)Karen Pocha-Melby (MSU)
- Accelerated growth at intermediate atrazine dosage; effect is corroborated in our lab in other experiments
- Axolotls undergo metamorphosis after TH-induction
- Failed to find any effect of atrazine on metamorphosis
Summation