Three-dimensional tracking of the ciliate Tetrahymena reveals the mechanism of ciliary stroke-driven helical swimming

Helical swimming in free-space is a common behavior among microorganisms, such as ciliates that are covered with thousands hair-like motile cilia, and is thought to be essential for cells to orient directly to an external stimulus. However, a direct quantification of their three-dimensional (3D) helical trajectories has not been reported, in part due to difficulty in tracking 3D swimming behavior of ciliates, especially Tetrahymena with a small, transparent cell body. Here, we conducted 3D tracking of fluorescent microbeads within a cell to directly visualize the helical swimming exhibited by Tetrahymena. Our technique showed that Tetrahymena swims along a right-handed helical path with right-handed rolling of its cell body. Using the Tetrahymena cell permeabilized with detergent treatment, we also observed that influx of Ca2+ into cilia changed the 3D-trajectory patterns of Tetrahymena swimming, indicating that the beating pattern of cilia is the determining factor in its swimming behavior.

PSV-4 Determination of Deoxynivalenol (DON) Content in Biological Samples as an Indicator of DON Intake in Grower-finisher Pigs

Due to difficulties in obtaining consistent and/or reliable measures of deoxynivalenol (DON) in complete swine diets, we investigated whether measuring DON in biological samples could be used as an indicator of DON ingestion in pigs. In this study, graded levels of DON (1, 3, or 5 ppm) were fed to grower-finisher pigs for a period of 77-d. On d 35 and 77 of the study, urine samples were quantitatively collected over a 24-h period and blood samples were collected between 3 – 4 h after the morning meal on each of those days for serum DON analysis. For direct quantification of DON in urine, high-performance liquid chromatography with tandem mass spectrometry was performed. For serum samples, indirect quantification of DON was performed via enzymatic hydrolysis. We observed that DON content in urine increased linearly as intake of DON increased (Fig.1A; P < 0.05). Analysis of DON in serum follow a similar trend, where serum DON content was increased as DON intake increased (Fig.1B; P < 0.05). An average of 30% of DON ingested was recovered as DON in urine over a 24-h period. In summary, there was a linear relationship between DON intake and DON content in both urine and blood serum, therefore, analyzing DON concentration in serum and urine could be used as a tool to estimate for DON exposure in pigs under controlled conditions.