Design and synthesis of a second-generation ligand-tethered calcium indicator for plant cell biology based on the fundamental analyses of the structure and physical property

Calcium ion (Ca²⁺) is one of the most important second messengers. However, conventional Ca²⁺ indicators cannot be applied in plant cells. In previous paper, we developed the first-generation protein-ligand tethered calcium indicator that can be applied for living plant cells.Here, we will report the development of second-generation indicator based on the detailed examination on physical properties of the first-generation to improve the drawbacks. Through the examination, we also found that cell permeability of the probe is strongly affected by their aggregation properties. Our findings will provide new strategy for the design of synthetic indicators.     

Fluorescence Properties of Diphenylthiazolo[4,5‐b]pyrazines Tuned by Donor‐Acceptor Substituent Effects

Fluorescence properties of 2,6‐ and 2,5‐diphenylthiazolo[4,5‐b]pyrazine (TPy) derivatives having an electron‐donating substituent (methoxy and dimethylamino) on the 6‐ and 5‐phenyl groups were studied. It was found that 2,6‐diphenyl derivatives fluoresce more efficiently than 2,5‐diphenyl derivatives. Furthermore, a 2,6‐diphenyl derivative having an additional cyano group on the 2‐phenyl ring was an excellent fluorophore showing a wide solvatochromism with great fluorescence yields. Based on the obtained spectroscopic data and mechanistic explanations concerning the substituent effects on the fluorescence properties, useful information on designing new TPy fluorophores is provided.     

Integrable Highest Weight Modules over Affine Superalgebras and Appell's Function

We classify integrable irreducible highest weight representations of non-twisted affine Lie superalgebras. We give a free field construction in the level 1 case. The analysis of this construction shows, in particular, that in the simplest case of the sℓ (2|1) level 1 affine superalgebra the characters are expressed in terms of the Appell elliptic function. Our results demonstrate that the representation theory of affine Lie superalgebras is quite different from that of affine Lie algebras. Received: 17 April 2000 / Accepted: 7 July 2000     

Stability of radio-metallofullerenes against beta-decay

The effect of β⁻-decay on the stability of metallofullerenes was investigated for three decay chains of¹⁵⁵Sm-¹⁵⁵Eu,¹⁶¹Gd-¹⁶¹Tb and¹⁷⁷Yb-¹⁷⁷Lu. For the former two cases, the metallofullerenes were found stable even after the β⁻-decay while in the case of¹⁷⁷Yb, the metallofullerene became unstable after β⁻-decay. The present results point to the fact that metallofullerenes are stable against ordinary β⁻-decay unstable after β⁻-decay. The present results point to the fact that metallofullerenes are stable against ordinary β⁻-decay recoil energies, but they become unstable if the oxidation state of the metal atom is changed by nuclear transformation.     

Involvement of the γ Isoform of cPLA2 in the Biosynthesis of Bioactive N-Acylethanolamines

Arachidonylethanolamide (anandamide) acts as an endogenous ligand of cannabinoid receptors, while other N-acylethanolamines (NAEs), such as palmitylethanolamide and oleylethanolamide, show analgesic, anti-inflammatory, and appetite-suppressing effects through other receptors. In mammalian tissues, NAEs, including anandamide, are produced from glycerophospholipid via N-acyl-phosphatidylethanolamine (NAPE). The ɛ isoform of cytosolic phospholipase A₂ (cPLA₂) functions as an N-acyltransferase to form NAPE. Since the cPLA₂ family consists of six isoforms (α, β, γ, δ, ɛ, and ζ), the present study investigated a possible involvement of isoforms other than ɛ in the NAE biosynthesis. Firstly, when the cells overexpressing one of the cPLA₂ isoforms were labeled with [¹⁴C]ethanolamine, the increase in the production of [¹⁴C]NAPE was observed only with the ɛ-expressing cells. Secondly, when the cells co-expressing ɛ and one of the other isoforms were analyzed, the increase in [¹⁴C]N-acyl-lysophosphatidylethanolamine (lysoNAPE) and [¹⁴C]NAE was seen with the combination of ɛ and γ isoforms. Furthermore, the purified cPLA₂γ hydrolyzed not only NAPE to lysoNAPE, but also lysoNAPE to glycerophospho-N-acylethanolamine (GP-NAE). Thus, the produced GP-NAE was further hydrolyzed to NAE by glycerophosphodiesterase 1. These results suggested that cPLA₂γ is involved in the biosynthesis of NAE by its phospholipase A₁/A₂ and lysophospholipase activities.     

Probing new intra-atomic force with isotope shifts

In the development of atomic clocks, some atomic transition frequencies are measured with remarkable precision. These measured spectra may include the effects of a new force mediated by a weakly interacting boson. Such effects might be distilled out from possible violation of a linear relation in isotope shifts between two transitions, as known as King’s linearity, with relatively suppressed theoretical uncertainties. We discuss the experimental sensitivity to a new force in the test of the linearity as well as the linearity violation owing to higher-order effects within the Standard Model. The sensitivity to new physics is limited by such effects. We have found that, for \(\hbox {Yb}^{+}\), the higher-order effect is in the reach of future experiments. The sensitivity to a heavy mediator is also discussed. It is analytically clarified that the sensitivity becomes weaker than that in the literature. Our numerical results of the sensitivity are compared with other weak force search experiments.     

牙鲆群体Idh-1基因座位杂合型个体选择性优势

利用淀粉凝胶水平电泳法分析了人工牙鲆种苗群体的异柠檬酸脱氢酶同工酶 (IDH) .对牙鲆材料分析得知 Idh- 1基因座位只存在 A、B两个等位基因 ,而且在 2 3个样品群中 ,有 19个样品群呈现 A、B这两个等位基因所决定的基因型的杂合型个体过剩现象 ,表现出杂合基因型的选择性优势 .设定这 19个呈杂合型过剩样品群的死亡率为零 ,即以杂合型 A/ B的成活率为 10 0 %来计算其纯合型的成活率 ,得到纯合型个体 A/ A和 B/ B的成活率分别为 6 9.2 %和 75 .2 % ;从个体的标准体长上看 ,在表现为杂合型个体过剩的 19个样品群中 ,15个样品群的杂合型个体 (A/ B)大于纯合型个体 (B/ B) .其结果反映了牙鲆人工养殖放流群体的 Idh- 1的基因型与成活率及生长存在相关性 .     

Heat of Reaction of the Hydrolysis-Polymerization Process of Tetraethyl Orthosilicate in Acidic Condition

Heat of reaction of the hydrolysis-polymerization process of tetraethyl orthosilicate with water in acidic condition was investigated to clarify the thermodynamic driving force of sol-gel reactions. Heat of reaction was measured using an isoperibol calorimeter by mixing a dilute tetraethyl orthosilicate (TEOS) ethanolic solution with another solution of water, ethanol, and hydrochloric acid. The temperature change of the reaction cell had been measured more than 24 hours after mixing under the quasi-isothermal condition. Large exothermic reaction (12.9 kJ·mol^–1 for 1 mole of TEOS) due to the hydrolysis of TEOS was observed. A slow exothermic reaction followed it, and after that, the sol-gel reaction was changed to a small endothermic one.     

Simulation of soil deformation and resistance at bar penetration by the Distinct Element Method

A mechanical model of soil is constructed using the Distinct Element Method (DEM) which makes it possible to analyze the discontinuous property of soil. To discuss the applicability of the soil model by the DEM, a bar penetration test was conducted and the result was compared with the simulation results. From the results of the behavior of elements, it could be said that the mechanical model by the DEM could well simulate the discontinuous behavior of soil and the parameters used in the simulation play important roles to make the soil model useful. As for the penetrating resistance, some problems which lie in the present DEM model are discussed and the key to solving these problems is indicated. Moreover, the method to determine the time interval used in the DEM simulations is mentioned in terms of the stability of the solution in the calculation.