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Wave power generation has been the object of extensive renewable energy research and development all over the world. Concerning the application of a wave energy converter to the harsh environment of the South China Sea, a study of the shape and internal layout of a pitching float wave energy converter was performed based on the mechanism of the oscillating‐float generator. Research methods based on potential flow theory and the use of ANSYS‐AQWA software were applied to predict the hydrodynamic performance and energy conversion of the pitching float wave energy converter. The influence of the float shape, width, side radius, and centroid position on the hydrodynamic performance of the float was analyzed. The results show that the pitching performance of the spherical‐bottom float was the best among the three basic shapes examined. The width of the float had the greatest impact on the pitching performance of the float, and the effect of the radius of the float on the pitching performance was also significant. The pitching performance of the float was improved with the realization of a larger radius in the pitching direction. The centroid position and rotational inertia also had a great impact on the pitching performance of the float. The wave energy converter designed in this study lays the foundation and provides reference for further research on the novel, efficient, and stable wave energy converter. [ABSTRACT FROM AUTHOR]

Summary: The plant Shaker K+ channel AtAKT2 has been identified as a weakly rectifying channel that can stabilize membrane potentials to promote photoassimilate phloem loading and translocation. Thus, studies on functional characterization and regulatory mechanisms of AtAKT2‐like channels in crops are highly important for improving crop production. Here, we identified the rice OsAKT2 as the ortholog of Arabidopsis AtAKT2, which is primarily expressed in the shoot phloem and localized at the plasma membrane. Using an electrophysiological assay, we found that OsAKT2 operated as a weakly rectifying K+ channel, preventing H+/sucrose‐symport‐induced membrane depolarization. Three critical amino acid residues (K193, N206, and S326) are essential to the phosphorylation‐mediated gating change of OsAKT2, consistent with the roles of the corresponding sites in AtAKT2. Disruption of OsAKT2 results in delayed growth of rice seedlings under short‐day conditions. Interestingly, the lipid second messenger phosphatidic acid (PA) inhibits OsAKT2‐mediated currents (both instantaneous and time‐dependent components). Lipid dot‐blot assay and liposome‐protein binding analysis revealed that PA directly bound with two adjacent arginine residues in the ANK domain of OsAKT2, which is essential to PA‐mediated inhibition of OsAKT2. Electrophysiological and phenotypic analyses also showed the PA‐mediated inhibition of AtAKT2 and the negative correlation between intrinsic PA level and Arabidopsis growth, suggesting that PA may inhibit AKT2 function to affect plant growth and development. Our results functionally characterize the Shaker K+ channel OsAKT2 and reveal a direct link between phospholipid signaling and plant K+ channel modulation. Significance Statement: Phospholipids function as second messengers, modulating some kinds of ion channels in animal cells, but in plants, phospholipid‐mediated modulation of ion channels remains unclear. Herein, we identified OsAKT2 (a Shaker family member in rice) as a weakly rectifying K+ channel and found that phosphatidic acid, a lipid mediator, inhibited OsAKT2 activity by binding with two adjacent arginine residues in the ANK domain, revealing a direct link between phospholipid signaling and plant K+ channel modulation. [ABSTRACT FROM AUTHOR]

Objectives: Mammalian spermatogenesis is a biological process of male gamete formation. Gonocytes are the only precursors of spermatogonial stem cells (SSCs) which develop into mature spermatozoa. DDX5 is one of DEAD‐box RNA helicases and expresses in male germ cells, suggesting that Ddx5 plays important functions during spermatogenesis. Here, we explore the functions of Ddx5 in regulating the specification of gonocytes. Materials and Methods: Germ cell‐specific Ddx5 knockout (Ddx5‐/‐) mice were generated. The morphology of testes and epididymides and fertility in both wild‐type and Ddx5‐/‐ mice were analysed. Single‐cell RNA sequencing (scRNA‐seq) was used to profile the transcriptome in testes from wild‐type and Ddx5‐/‐ mice at postnatal day (P) 2. Dysregulated genes were validated by single‐cell qRT‐PCR and immunofluorescent staining. Results: In male mice, Ddx5 was expressed in germ cells at different stages of development. Germ cell‐specific Ddx5 knockout adult male mice were sterile due to completely devoid of germ cells. Male germ cells gradually disappeared in Ddx5‐/‐ mice from E18.5 to P6. Single‐cell transcriptome analysis showed that genes involved in cell cycle and glial cell line‐derived neurotrophic factor (GDNF) pathway were significantly decreased in Ddx5‐deficient gonocytes. Notably, Ddx5 ablation impeded the proliferation of gonocytes. Conclusions: Our study reveals the critical roles of Ddx5 in fate determination of gonocytes, offering a novel insight into the pathogenesis of male sterility. [ABSTRACT FROM AUTHOR]