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Marine picophytoplankton (Pico) as a major contributor to primary productivity in oligotrophic waters, play a very important role in marine material cycle and energy conversion, and their key role in the carbon cycle and global climate change is increasingly emphasized. To study the factors affecting the dynamic distribution of Synechococcus, Prochlorococcus, and picoeukaryotes in the East China Sea (ECS), a marginal sea of the Northwest Pacific, we investigated 27 stations in May 2017, and collected 148 samples of Pico and nutrients from the surface to the bottom. By means of flow cytometry, the abundance of Pico was measured, and then we estimated the carbon biomass and analyzed the distribution of Pico. Finally, combined with the ECS unique geographical situation and hydrological regime, we evaluated various factors affecting the Pico in the ECS. In Pico community, the picoeukaryotes cell abundance was between 0.49×102−1.44×104 cells/mL. Prochlorococcus ranged from 1.36×103−3.47×104 cells/mL and Synechococcus ranged from 0.69×103−1.15×105 cells/mL. Synechococcus was the most, both in abundance and in carbon biomass. Picoeukaryotes were the least in abundance, but has larger contribution to carbon biomass than Prochlorococcus. Water temperature, salinity, and stability of water column influenced Pico distribution. Picoeukaryotes were abundant in the shelf sea, whereas Synechococcus and Prochlorococcus were detected in the northeast of Taiwan, China. This study provided basic information for the study of Pico communities in the ECS and its adjacent marine ecosystem. [ABSTRACT FROM AUTHOR]

Background: No effective treatment is currently available for poorly differentiated thyroid cancer which is resistant to radioiodine, especially with migration and invasion. A great number of researches have revealed the anticancer effects of salidroside, but none have studied the effects of salidroside on thyroid cancer. This study aimed to investigate the effect of salidroside on migration and invasion of poorly differentiated thyroid cancer cells. Methods: The effects of salidroside on migration, invasion and apoptosis of poorly differentiated thyroid cancer WRO cells and normal thyroid follicular epithelial Nthy‐ori 3‐1 cells were measured by wound‐healing assay, transwell migration/invasion assay and flow cytometry, respectively. The expression levels of MMP2 and MMP9 at RNA and protein levels in WRO cells were detected by qRT‐PCR and western blot. The phosphorylation levels of Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3) and the apoptosis‐related protein levels of Bax, cleaved caspase 3 and Bcl‐2 were assessed by western blot. Results: Salidroside significantly suppressed migration/invasion and induced apoptosis in poorly differentiated thyroid cancer WRO cells. We further illustrated that salidroside significantly inhibited expressions of MMP2 and MMP9 at mRNA and protein levels and the phosphorylation activation of JAK2/STAT3 in WRO cells. In addition, salidroside increased expressions of pro‐apoptotic factors (Bax and cleaved caspase 3) and decreased expression of anti‐apoptotic factor (Bcl‐2) significantly in WRO cells. Conclusion: The present study demonstrates that salidroside inhibits migration and invasion of WRO cells (a kind of poorly differentiated cancer cell line) significantly, which might be via suppressing JAK2‐STAT3 signaling pathway. [ABSTRACT FROM AUTHOR]

Simple Summary: In order to accurately characterize the composition of the picophytoplankton community by size in the marine environment, we used a size-fractionated filtration plus a high-throughput sequencing molecular method. The results showed that this method can detect the composition of picophytoplankton in different particle size ranges in detail, and it is accurate in assessing the vertical distribution patterns and size of phytoplankton. This method can enrich the study of phytoplankton communities with diameters of less than 2 μm. In this study, flow cytometry (FCM) and size-fractionated filtration, together with high-throughput molecular sequencing methods (SM), were used to investigate picophytoplankton. A particle separation filter and a higher-throughput sequencing method were used to evaluate the composition of a euphotic zone of picophytoplankton—especially picoeukaryotic phytoplankton—in the Western Pacific, and the results of flow cytometry, which is a classic way to detect picophytoplankton, were used as a standard to evaluate the reliability of the results of the SMs. Within a water column of 200 m, six water depths (5, 25, 50, 113 (DCM), 150, and 200 m) were established. In order to further study the particle size spectra of the picophytoplankton, size-fractionated filtration was used to separate water samples from each water depth into three particle size ranges: 0.2–0.6, 0.6–1.2, and 1.2–2 μm. A total of 36 (6 × 3 × 2) samples were obtained through PCR amplification of the 18S rRNA V4 hypervariable region and 16S rRNA, which were biased toward phytoplankton plastids, and then high-throughput sequencing was performed. The estimation of the picophytoplankton diameter relied on forward scattering (FSC) through FCM. The estimation of the vertical distribution and diameter of the picophytoplankton using the SM was consistent with the results with FCM; thus, we believe that the estimation of picophytoplankton composition with the SM has value as a reference, although the size-fractionated filtration seemed to cause some deviations. In addition to Prochlorococcus and Synechococcus, the SM was used to evaluate the composition of picoeukaryotic phytoplankton, which mainly included Prymnesiophycea (Haptophyta) (38.15%), Cryptophyceae (Cryptophyta) (22.36%), Dictyochophyceae (Chrysophyta) (12.22%), and Mamiellophyceae (Chlorophyta) (3.31%). In addition, the SM also detected Dinophyceae (Dinoflagellata) (11.69%) sequences and a small number of Bacillariophyceae (Diatom) (1.64%) sequences, which are generally considered to have large particle sizes. The results of the SM also showed that the picoeukaryotic phytoplankton were not evenly distributed in the euphotic layer, and the vertical distributions of the different picoeukaryotic phytoplankton were different. An analysis of correlations with environmental factors showed that temperature was the main environmental factor controlling the vertical distribution of picophytoplankton. [ABSTRACT FROM AUTHOR]