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.

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.

We've had several setbacks over the past few weeks concerning our cultures. Our starter cultures are experiencing population wipeout, with both Cultures A and B dwindling severely in numbers. We were able to determine a closer range of EE2 dosages by diluting our original HIGH (2000um/L), MEDIUM (1500um/L), and LOW (1000um/L) concentrations down to numbers between 300-900 um of EE2 per L. Unfortunately, while we were testing these concentrations, our negative concentration also experienced high mortality, indicating that there are problems with our husbandry procedures. We are currently waiting for our starter cultures to recover more before attempting another trial.

Because of shortages in time, we might not be able to complete any more pre-trials; instead, we may be forced to complete one singular experimental trial as opposed to several weeks of data collection. To collect the appropriate number of data points, we will be testing only one concentration of EE2 in several identical containers for a minimum of 120 data points.

To improve the viability of our cultures, we are experimenting with feeding them more, as research demonstrated that the color of the D. magna is indicative of the state of their food supply; if they are brightly pigmented, then they are well-fed, but if they are translucent like our current cultures, they are most likely closer to starvation.

Below are several clear images of the D. magna magnified under the EVOS microscope.