Shimane University

Aquatic plants are essential to the foundation of lake ecosystems; however, some lakes are experiencing issues due to abnormal overgrowth of submerged macrophytes.To investigate the factors driving such outbreaks, we conducted long-term monitoring using environmental DNA (eDNA), focusing on Potamogeton pusillus and Stuckenia pectinata in Lake Shinji, a brackish lake in Japan.We performed eDNA anal. of these two submerged macrophytes using monthly water samples collected from 2016 to 2022.This allowed us to estimate annual fluctuations and seasonal patterns in biomass based on eDNA concentrations of both species.Addnl., it was suggested-and these results were consistent with the trends of field observations-that the biomass of S. pectinata has recently increased relative to that of P. pusillus.In analyzing the relationships between eDNA concentrations and five water parameters (water temperature, pH, elec. conductivity (EC), nitrate ion concentration (NO^-₃), and salinity) in Lake Shinji, we found that P. pusillus eDNA was pos. correlated with water temperature and neg. correlated with salinity.No such relationship was observed for S. pectinata.Given that S. pectinata has a higher tolerance to salinity than P. pusillus, the recent increase in salinity of Lake Shinji may have led to a shift from P. pusillus to S. pectinata as dominant species.To our knowledge, this is the first study to use long-term eDNA monitoring to evaluate the biomass of submerged macrophytes in a lake and to explore the underlying causes.

To evaluate the effect of disease stage, frequency and clustering of visual field (VF) tests, inclusion of 1 or both eyes, and 1 (1 arm; before and after a treatment) or 2 groups (2 arms; treatment and control arm) on sample size calculation in clinical trials.

Clinical cohort study.

A series of VFs were simulated based on test-retest VF data in the early, moderate, and advanced stages of glaucoma with 231, 204, and 226 eyes, respectively.

The mean of mean deviation (MD) slope was -0.75 decibels (dB)/year before treatment initiation in the 1-arm trial, and in the control group in the 2-arm trial. Visual field measurements were scheduled as 8 times in 2 years.

Sample size calculation in clinical trials.

In the 1-arm trial, when only 1 eye was used in each patient, the 80% probability of significance in the moderate stage was observed with sample size = 70 eyes. Disease in the early stage and inclusion of both eyes decreased this number to 30 eyes; these decreasing effects were significantly larger than performing 1 or 2 additional VFs at the beginning and end of the observation. Conversely, a greater number of eyes was necessary in advanced stage than in moderate stage. In the 2-arm trial (80% probability of significance, and 1 eye per patient), the 80% probability of significance was observed with sample size = 80 eyes in each arm, a tendency that was similar to what observed for the 1-arm trial. Similar tendency was observed in the simulations with much slower VF progression (mean MD slope = -0.25 dB/year).

The present study highlights the importance of considering disease stage when planning a clinical trial.

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Paramecium bursaria is a ciliate species that has a symbiotic relationship with Chlorella spp. This study aimed to elucidate the dynamics of digestive vacuole (DV) differentiation in P. bursaria, using yeast stained with a pH indicator. Previously, DV differentiation in P. bursaria has been classified into eight periods based on fixed-cell observations. However, to understand the behavior and physiology of P. bursaria in its natural state, it is essential to observe living cells. This study presented a novel method using Cornig® Cell-Tak™ to immobilize living P. bursaria cells, which enabled long-term observation of the same cell from the same direction. This technique allowed for real-time observation of DV differentiation, including the relationship between changes in the internal pH of DV and the diameter of DV, yeast budding from the DV membrane by a single cell into the cytoplasm, and separation of a DV containing multiple yeasts into two DVs. This study provides new insights into the dynamic process of DV differentiation in P. bursaria. These findings contribute to a better understanding of the cellular mechanisms underlying the symbiotic relationship between the two organisms and shed light on the complex process of intracellular digestion in ciliates.