The TPLATE complex mediates membrane bending during plant clathrin–mediated endocytosis

Clathrin-mediated endocytosis is the major route of entry of cargos into cells and thus underpins many physiological processes. During endocytosis, an area of flat membrane is remodeled by proteins to create a spherical vesicle against intracellular forces. The protein machinery which mediates this membrane bending in plants is unknown. However, it is known that plant endocytosis is actin independent, thus indicating that plants utilize a unique mechanism to mediate membrane bending against high-turgor pressure compared to other model systems. Here, we investigate the TPLATE complex, a plant-specific endocytosis protein complex. It has been thought to function as a classical adaptor functioning underneath the clathrin coat. However, by using biochemical and advanced live microscopy approaches, we found that TPLATE is peripherally associated with clathrin-coated vesicles and localizes at the rim of endocytosis events. As this localization is more fitting to the protein machinery involved in membrane bending during endocytosis, we examined cells in which the TPLATE complex was disrupted and found that the clathrin structures present as flat patches. This suggests a requirement of the TPLATE complex for membrane bending during plant clathrin–mediated endocytosis. Next, we used in vitro biophysical assays to confirm that the TPLATE complex possesses protein domains with intrinsic membrane remodeling activity. These results redefine the role of the TPLATE complex and implicate it as a key component of the evolutionarily distinct plant endocytosis mechanism, which mediates endocytic membrane bending against the high-turgor pressure in plant cells.

Fouling Mitigation via Chaotic Advection in a Flat Membrane Module with a Patterned Surface

Fouling mitigation using chaotic advection caused by herringbone-shaped grooves in a flat membrane module is numerically investigated. The feed flow is laminar with the Reynolds number (Re) ranging from 50 to 500. In addition, we assume a constant permeate flux on the membrane surface. Typical flow characteristics include two counter-rotating flows and downwelling flows, which are highly influenced by the groove depth at each Re. Poincaré sections are plotted to represent the dynamical systems of the flows and to analyze mixing. The flow systems become globally chaotic as the groove depth increases above a threshold value. Fouling mitigation via chaotic advection is demonstrated using the dimensionless average concentration (c¯w*) on the membrane and its growth rate. When the flow system is chaotic, the growth rate of c¯w* drops significantly compared to that predicted from the film theory, demonstrating that chaotic advection is an attractive hydrodynamic technique that mitigates membrane fouling. At each Re, there exists an optimal groove depth minimizing c¯w* and the growth rate of c¯w*. Under the optimum groove geometry, foulants near the membrane are transported back to the bulk flow via the downwelling flows, distributed uniformly in the entire channel via chaotic advection.

AUTOMATED DEVICE FOR MONITORING THE STATOR CORE OF POWERFUL TURBOGENERATOR

A device for automated control by the stator core of a powerful turbine generator (TG) during assembly and pressing at the manufacturing plant is proposed. Using the device, places in the core with a weakened solidity are determined. For this, at N points evenly spaced along the cross section of the stator core, the specific pressing pressure of special plastic elements, which are installed in the control cells of the additional pressure ring of the press, on which the core is assembled, is measured. During pressing, the elements are deformed, and their deformation depends on the degree of core defect (decrease in solidity) in the zone of which they are located. The sample will be deformed less, located in the zone of the largest defect, and most of all - in the zone where the defect is minimal. The pressure is measured using a flat metal membrane with a rigid center on which strain gauges are located at selected points. It is shown that the relative deformations in a flat membrane, which are measured by strain gages, depend on the value of the specific pressing pressure. Analytical relationships between the relative radial and tangential deformations and the specific pressing pressure have been determined. References 20, figures 5.

Difference between SFMR and SITMR 1 compensation for hydrostatic thrust bearing

Both flat and island type membranes are used in single-action membrane restrictors. But the difference between the single-action flat membrane restrictor (SFMR) and the single-action island type membrane restrictor (SITMR) has rarely been reported in the literature. In this study, we first compared the static and dynamic characteristics of SFMR and SITMR, and found that there is a little difference between them when the difference between supply pressure ps and outlet pressure pr is not large. Then, we investigated the dynamic characteristics of hydrostatic thrust bearings using both SFMR and SITMR compensation, and found SITMR having a better dynamic bearing performance. The reason for this phenomenon is that the mass of the membrane in SITMR is smaller than that of the membrane in SFMR. When the difference between supply pressure ps and outlet pressure pr becomes large, SFMR reduces the static flow rate of the lubricant of bearing systems more significantly than SITMR.

Visualizing sequential compound fusion and kiss-and-run in live excitable cells

Vesicle fusion is assumed to occur at flat membrane of excitable cells. In live neuroendocrine cells, we visualized vesicle fusion at Ω-shape membrane generated by preceding fusion, termed sequential compound fusion, which may be followed by fusion pore closure, termed compound kiss-and-run. These novel fusion modes contribute to vesicle docking, multi-vesicular release, asynchronous release, and endocytosis. We suggest modifying current models of exo-endocytosis to include these new fusion modes.