Potential Parasite and Possible Results

This week, we imaged what we believe to be a parasite on one of our Daphnia magna under the EVOS microscope. Alternatively, it could also be the maxillary gland that regulates oxygen and ion intake. Regardless, it is bright red in color and appears on the outside right edge of the D. magna body. This organism could not be monitored post-imaging because upon returning, its heart had stopped beating.

We also analyzed the cross-sectional areas of several control (non-estrogen) organisms as compared to that of one D. magna exposed to estrogen. In this analysis, we found that while the average ratio of heart cross-sectional area (CSA) to body CSA in a normal D. magna is 1.9%, the ratio in an estrogen-exposed D. magna was 3.4%. This is an astonishing increase and is in line with our hypothesis. Because this is only one datapoint, it is not entirely significant, but it could still be indicative of future results after spring break. The average CSA ratio of the non-estrogen D. magna was calculated using both male and female organisms, demonstrating that differences in sex are not significant when discussing the proportion of heart to body. This is especially important because female D. magna are significantly larger in both length and width than males, so it must be ensured that these differences do not cause problems.

​Pictured to the left are images of the D. magna exposed to estrogen, where heart area divided by body area was 3.4%. In the left image, the heart is outlined in yellow to be measured, and in the right image, the outside of the body has been traced.

Upon qualitative analysis of two D. magna under a standard microscope, it has also become clear that the D. magna exposed to estrogen have a significantly increased heart rate. Although we have not calculated the difference quantitatively, it is visually apparent upon comparison with previous D. magna ​videos. They also appear to be seizing at times. Again, this is not technical data because there are only two data points thus far. To view these videos, click the links below.

EE2 Daphnia Heart Beat.mov
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EE2 Daphnia Heart Beat 2.mov
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