Reconstitution of dynamic microtubules with Drosophila XMAP215, EB1, and Sentin

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Cell Biology 199 (2012): 849-862, doi:10.1083/jcb.201206101.Dynamic microtubules (MTs) are essential for various intracellular events, such as mitosis. In Drosophila melanogaster S2 cells, three MT tip-localizing proteins, Msps/XMAP215, EB1, and Sentin (an EB1 cargo protein), have been identified as being critical for accelerating MT growth and promoting catastrophe events, thus resulting in the formation of dynamic MTs. However, the molecular activity of each protein and the basis of the modulation of MT dynamics by these three factors are unknown. In this paper, we showed in vitro that XMAP215msps had a potent growth-promoting activity at a wide range of tubulin concentrations, whereas Sentin, when recruited by EB1 to the growing MT tip, accelerated growth and also increased catastrophe frequency. When all three factors were combined, the growth rate was synergistically enhanced, and rescue events were observed most frequently, but frequent catastrophes restrained the lengthening of the MTs. We propose that MT dynamics are promoted by the independent as well as the cooperative action of XMAP215msps polymerase and the EB1–Sentin duo.This work was supported by a Next Generation grant (Japan Society for the Promotion of Science), the Inoue Foundation, and the Human Frontier Science Program (to G. Goshima). W. Li was supported by the Global Centers of Excellence program, the Leading Graduate School program, and the State Scholarship Study Abroad Program of the Chinese Scholarship Council.2013-05-2

Enhancement of optical force acting on vesicles via the binding of gold nanoparticles

Here we found that gold nanoparticles (AuNPs) enhance the optical force acting on vesicles prepared from phospholipids via hydrophobic and electrostatic interactions. A laser beam was introduced into a cuvette filled with a suspension of vesicles and it accelerated them in its propagation direction via a scattering force. The addition of the AuNPs exponentially increased the velocity of the vesicles as their concentration increased, but polystyrene particles had no significant impact on velocity in the presence of AuNPs. To elucidate the mechanism of the increased velocity, the surface charges in the vesicles and the AuNPs were controlled; the surface charges of the vesicles were varied via the use of anionic, cationic and neutral phospholipids, whereas AuNPs with positive and negative charges were synthesized by coating with citrate ion and 4-dimethylaminopyridine, respectively. All vesicles increased the velocity at different degrees depending on the surface charge. The vesicles were accelerated more efficiently when their charges were opposite those of the AuNPs. These results suggested that hydrophobic and electrostatic interactions between the vesicles and the AuNPs enhanced the optical force. By accounting for the binding constant between the vesicles and the AuNPs, we proposed a model for the relationship between the concentration of the AuNPs and the velocity of the vesicles. Consequently, the increased velocity of the vesicles was attributed to the light scattering that was enhanced when AuNPs were adsorbed onto the vesicles

肝切除後肝再生時のロイコトリエンB[4]の変動と5-リポキシゲナーゼ代謝阻害剤の肝再生に及ぼす影響についての実験的研究: 正常肝および閉塞性黄疸肝での検討

取得学位 : 博士（医学）, 学位授与番号 : 医博乙第1304号, 学位授与年月日：平成6年6月15日,学位授与年：199

The Effects of Font Type on Reading Accuracy and Fluency in Japanese Children with Developmental Dyslexia

We administered rapid reading tasks in Japanese children (32 with typical development and 24 with developmental dyslexia), and investigated the effects of two different font types: Rounded-Gothic and Mincho style font. In the experiment, we used four kinds of stimuli: two scripts (paragraphs and random kana character non-words) in two font types (Rounded-Gothic and Mincho style font). In this experiment, the duration time, the number of errors and the number of self-corrections were measured during reading. Participants were asked which font type was easier to read. There was no significant difference in the duration time, the number of errors and the number of self-corrections between two types of fonts among the 56 participants. On the other hand, regarding subjective readability, the developmental dyslexia group reported that the Rounded-Gothic font was easier to read. There was a difference between objective and subjective readability. In this study, there was no difference in reading performance of Rounded-Gothic and Mincho style fonts in Japanese children with developmental dyslexia

A new bioactive cembranoid sarcophytonolide V from Bornean soft coral genus Sarcophyton

A new cembranolide diterpene, sarcophytonolide V (1), along with 6 known compounds, isosarcophytonolide D (2), (4Z,8S*,9R*,12E,14E) -9-hydroxy-1- (prop-1-en-2-yl) -8,12- dimethyl- oxabicyclo[9.3.2]-hexadeca-4,12,14-trien-18-one (3), (7E,11E)-3,4-epoxy-7,11, 15- cembratriene (4), (1S*,3S*,4S*,7E,11E)-3,4-epoxy-13-oxo-7,11,15-cembratriene (5), (-) -eunicenone (6), and 2-[(E,E,E)-7′, 8′-epoxy-4′,8′,12′ -trimethylcyclotetradeca- 1′,3′,11′- trienyl] propan-2-ol (7) were isolated from the Bornean soft coral Sarcophyton sp. Their structures were elucidated based on spectroscopic data, such as nuclear magnetic resonance (NMR) and high resolution electron spray ionization mass spectroscopy (HRESIMS). These compounds were evaluated for their biological activity against marine pathogenic fungi

Generation of monocycle efficient terahertz pulses by optical rectification in LiNBO3 at 800 nm

Generation of efficient terahertz (THz) pulses was experimentally made by tilted pump pulse front scheme with a Mg-doped LiNbO3 crystal. In this study, a spitfire laser (Ti:sapphire laser, 800 nm, 3 mJ, 1 kHz) was used as an optical source for the generation and detection of THz pulses. The electro-optic (EO) detection optics consisting of a ZnTe crystal (1 mm in thickness) and a balanced photodetector was used. To obtain optimum THz characteristics and pump to THz power conversion efficiency, the image of the grating was made coincides with the tilted pump pulse front. The maximum THz electric field of 8.5 kV/cm and the frequency bandwidth of 2.5 THz were achieved by using pump pulse energy of 2.4 mJ and pump pulse width of 100 fs. The THz energy of 4.15 μJ was obtained and pump-to-THz conversion efficiency was estimated to be approximately 1.73 x 10-3

Dynamics of Internal Models in Game Players

A new approach for the study of social games and communications is proposed. Games are simulated between cognitive players who build the opponent's internal model and decide their next strategy from predictions based on the model. In this paper, internal models are constructed by the recurrent neural network (RNN), and the iterated prisoner's dilemma game is performed. The RNN allows us to express the internal model in a geometrical shape. The complicated transients of actions are observed before the stable mutually defecting equilibrium is reached. During the transients, the model shape also becomes complicated and often experiences chaotic changes. These new chaotic dynamics of internal models reflect the dynamical and high-dimensional rugged landscape of the internal model space.Comment: 19 pages, 6 figure

New cembrane-type diterpenoids from Bornean soft coral N ephthea sp. with antifungal activity against Lagenidium thermophilum

Three new cembrane diterpenes, nephthecrassocolides A-B (1–2) and 6-acetoxy nephthenol acetate (3) along with three known compounds, 6-acetoxy-7,8-epoxy nephthenol acetate (4), epoxy nephthenol acetate (5) and nephthenol (6) were isolated from one population of Nephthea sp. Their structures were elucidated based on spectroscopic data analysis and the antifungal activities of compounds 1–6 were evaluated