Endocytosis performs a wide range of functions in animals and plants. Clathrin-coated vesicle (CCV) formation is an initial step of endocytosis, and in animal cells is largely achieved by dynamins. However, little is known of its molecular mechanisms in plant cells. To identify dynamin-related proteins (DRPs) involved in endocytic CCV formation in plant cells, we compared the behaviors of two structurally different Arabidopsis DRPs, DRP2B and DRP1A, with those of the clathrin light chain (CLC), a marker of CCVs, at the plasma membrane by variable incidence angle fluorescent microscopy (VIAFM). DRP2B shares domain organization with animal dynamins whereas DRP1A is plant-specific. We show that green fluorescent protein (GFP)-tagged DRP2B and DRP1A colocalized with CLC tagged with monomeric Kusabira Orange (mKO) in Arabidopsis cultured cells. Time-lapse VIAFM observations suggested that both GFP-DRP2B and GFP-DRP1A appeared and accumulated on the existing mKO-CLC foci and disappeared at the same time as or immediately after the disappearance of mKO-CLC. Moreover, DRP2B and DRP1A colocalized and assembled/disassembled together at the plasma membrane in Arabidopsis cells. A yeast twohybrid assay showed that DRP2B and DRP1A interacted with each other. An inhibitor of clathrin-mediated endocytosis, tyrphostin A23, disturbed the localization of DRP1A, but had little effect on the localization of DRP2B, indicating that DRP1A and DRP2B have different molecular properties. These results suggest that DRP2B and DRP1A participate together in endocytic CCV formation in Arabidopsis cells despite the difference of their molecular properties.

For the purpose of extending the theoretical interpretation of the large-scale equatorial waves discovered by Yanai and Maruyama (1966), a three-dimensional linearized primitive equation model of unstable waves is constructed on an equatorial beta plane.It is assumed that the release of latent heat due to moist convection in the troposphere is disturbed in proportion to the horizontal convergence in the subcloud layer responding to large-scale equatorial waves.It is found that Mode HB in the theory of unstable low latitude disturbances by Yamasaki (1969) is characterized by complex equivalent depth which simulates many aspects of YanaiMaruyama waves. This mode is further classified into various meridional modes, following Matsuno (1966). When the heat in the upper troposphere exceeds a critical value, unstable waves of free internal mode come into existence. Their growth rate increases with increasing heat in the upper troposphere.With the exception of inertio-gravity waves and Kelvin waves, mixed Rossby-gravity waves are the most unstable. The period corresponding to the observed wavelength of 10,000 km coincides with the observed period of about 4 days. The e-folding time is of the order of 10 days which, however, decreases with increasing wavelength.The energy and momentum budgets are also examined in detail. It is shown that a nonlinear forcing by Rossby type waves results in easterly acceleration of the mean zonal wind in the lower stratosphere, while Kelvin waves accelerate a westerly flow.

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Space-time spectral analysis methods and their applications to large-scale atmospheric waves are reviewed.

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The power spectra of the meridional component of the wind from the ground to the 30-km level at 17 stations in the tropical and sub-tropical Pacific are studied based on special upper wind observations taken during the period April through July 1962.In equatorial latitudes, the power spectra show a peak at a period close to 4 days corresponding to the passage of "equatorial waves" in the lower tropospheric easterlies. A very large spectral density is found at the periods 4 to 5 days throughout the upper troposphere and the lower stratosphere where the mean wind is from the west. The peak spectral density reaches a maximum at about the 17-km level near the tropopause. The spectral density gradually decreases with height in the stratosphere where the mean wind is from the east.In sub-tropical latitudes, large disturbance energy is associated with the upper tropospheric westerlies and a large portion of the spectral density is contained in the wave period longer than 5 days. A sharp suppression of the spectral density takes place at the lower boundary of the stratospheric easterlies.From the computation of the coherence and the phase difference of the meridional component of the wind, the vertical and horizontal structure of the disturbances is studied. The large horizontal extent and the westward inclination of phase lines of the disturbances in the upper troposphere and in the lower stratosphere are revealed. The horizontal coherence of the lower tropospheric disturbances in the east-west direction is very low. The phase lines of the lower tropospheric disturbances are inclined eastward with height. The average wavelength of the disturbances at various levels is estimated from the relation between the phase difference and the longitudinal difference of the stations.

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The ex vivo production of platelets depleted of human leukocyte antigen class I (HLA-I) could serve as a universal measure to overcome platelet transfusion refractoriness caused by HLA-I incompatibility. Here, we developed human induced pluripotent cell-derived HLA-Ideficient platelets (HLA-KO iPLATs) in a clinically applicable imMKCL system by genetic manipulation and assessed their immunogenic properties including natural killer (NK) cells, which reject HLA-I downregulated cells. HLA-KO iPLATs were deficient for all HLA-I but did not elicit a cytotoxic response by NK cells in vitro and showed circulation equal to wild-type iPLATs upon transfusion in our newly established Hu-NK-MSTRG mice reconstituted with human NK cells. Additionally, HLA-KO iPLATs successfully circulated in an alloimmune platelet transfusion refractoriness model of Hu-NK-MISTRG mice. Mechanistically, the lack of NK cell-activating ligands on platelets may be responsible for evading the NK cell response. This study revealed the unique non-immunogenic property of platelets and provides a proof of concept for the clinical application of HLA-KO iPLATs.