SUMMARY: There are many types of organisms that can dry out, rehydrate, and then go about their lives with no problems. Many of the larger ones use trehalose or sucrose as an antifreeze. Bdelloid rotifers (tiny microscopic animals) do not. This study looked at the carbohydrate content in desiccated rotifers compared with flatworms. Researchers found that rotifers not only contained no trehalose when they dried out, they also lacked the trehalose synthase gene. Desiccation is still being studied; the results of this experience show that another mechanism other than using sugar as an antifreeze is required for desiccation to occur.
LESSON COMMENTS: The methodology can be read alone and used as an example of the scientific method. Teachers can also talk about the antifreeze properties of sugar, what happens to cells when they freeze and why (since cells contain water). If you’re studying genetics, this article has some very straightforward genetic concepts (gene codes for an enzyme). You can even talk about the significance of PCR. Rotifers are easy to catch and observe under the microscope, students can find their own samples in ponds, puddles, or even bird baths (like in this article) and let the animals dry out as described in the methodology to observe rehydration.
Lapinski, J., & Tunnacliffe, A. (2003). Anhydrobiosis without trehalose in bdelloid rotifers. FEBS Letters,553(3), 387-390. doi:10.1016/s0014-5793(03)01062-7