|
|
|
|
|
|
||||
|
Results |
|||
|
Dose-dependence Upon initial qualitative analysis,
definite morphological differences were noted in the four
groups. Data were collected and statistical analysis was
used to clarify our observations. Trends of decreasing mass,
head diameter, and beak length with increasing ethanol
dosage were observed as seen by a negative slope in
regression analyses (Figure
1, Figure
2, Figure
3). We proceeded to determine
whether these differences were significant. No significant differences existed
between any of the chicks' masses (ANOVA: F-ratio = 1.3544,
p=0.2923) (Table
1). A significant difference
was measured in chick head diameter across the different
dosage groups (ANOVA: F-ratio = 22.010, p<=0.0001)
(Table
1). A Bonferroni post hoc
analysis indicated significant differences between 5% to
control (p=0.001244), 10% to control (p=0.000020), and 15%
to control (0.000067) (Table
2). No significant differences
were seen between any beak lengths (ANOVA: F-ratio = 3.0072,
p=0.0612) (Table
1). Although significant difference were
not always observed, a great deal of variation within each
measurement for each group was seen. Figure
4 illustrates the most notable
superficial difference in size between a control and a 10%
ethanol treated embryo. Figure
5 illustrates the difference
in head size between a control and a 10% ethanol treated
embryo. Figure
6 shows the difference in beak
size between a control and a 10% ethanol treated embryo. Temporal-dependence The eggs treated earlier, at 27-hours,
were smaller in mass, head diameter, and had shorter beak
length than those exposed to ethanol at 51-hours or the
control eggs, consistent with Lawrence and Yoder's study.
There were visible malformations particularly in the
craniofacial region, including missing beaks, misshaped
heads, and soft skulls (Figure
7). From the set of eggs treated at
51-hours, two ethanol-treated embryos and three control
embryos were harvested (Table
3). The eggs treated at
27-hours yielded seven experimental and one control embryo
(Table
4). All treated embryos were
smaller in mass and head diameter and had shorter beaks
compared to their respective control embryos. One embryo
exposed to ethanol at 27 hours was missing its beak
(Figure
7). Vital dye staining with Neutral Red
revealed more specific areas of apoptosis in both
ethanol-treated embryos, most prominently in the midbrain
area of the embryo treated at 27 hours (Figure
8). The embryo treated at 51
hours with ethanol did not exhibit staining in the head
region, but rather more caudally (Figure
9). Red dye was not present in
the control embryos (Figure
10). |
Last Modified: 10 May 2004
[Lab Protocols | Students | Cebra-Thomas | Course | Links ]