Single Molecule Imaging of Green Fluorescent Proteins in Living Cells: E-Cadherin Forms Oligomers on the Free Cell Surface

AbstractSingle green fluorescent protein (GFP) molecules were successfully imaged for the first time in living cells. GFP linked to the cytoplasmic carboxyl terminus of E-cadherin (E-cad-GFP) was expressed in mouse fibroblast L cells, and observed using an objective-type total internal reflection fluorescence microscope. Based on the fluorescence intensity of individual fluorescent spots, the majority of E-cad-GFP molecules on the free cell surface were found to be oligomers of various sizes, many of them greater than dimers, suggesting that oligomerization of E-cadherin takes place before its assembly at cell-cell adhesion sites. The translational diffusion coefficient of E-cad-GFP is reduced by a factor of 10 to 40 upon oligomerization. Because such large decreases in translational mobility cannot be explained solely by increases in radius upon oligomerization, an oligomerization-induced trapping model is proposed in which, when oligomers are formed, they are trapped in place due to greatly enhanced tethering and corralling effects of the membrane skeleton on oligomers (compared with monomers). The presence of many oligomers greater than dimers on the free surface suggests that these greater oligomers are the basic building blocks for the two-dimensional cell adhesion structures (adherens junctions)

Application of plant–soil feedbacks in the selection of crop rotation sequences

Plant–soil feedback (PSF) can be a major driver of plant performance in com- munities, and this concept can be used in selecting crop rotation sequences to maximize agricultural yields. Potential benefits of using PSF in this context include nutrient use optimization, pathogen reduction, and enhancement of mutualisms between crops and microbes. Yet the contributions of these com- bined mechanisms are poorly understood. Here we investigated the relative contributions of these mechanisms using five major crops commonly culti- vated in rotation (alfalfa, canola, maize, soybean, and wheat) under controlled conditions. We trained soil by growing each of the five crops in a “training phase,” and then reciprocally planted the five crops in the trained soils in a “feedback phase.” To tease out soil biota from nutrient effects, we established three treatments: “control” (trained unsterilized soil used in the feedback phases), “biota” (sterilized soil in the feedback phase inoculated with soil biota from the control treatment after the training phase), and “nutrient” (sterilized soils in both phases). Plant–soil feedback for each crop was calculated by com- paring the total biomass of each crop grown in soils trained by each of the four other crops (i.e., in rotation) against total biomass in self-trained soil (i.e., monocropping). We found that PSF values varied among crop combina- tions in all the treatments, but such variation was the greatest in the nutrient treatment. Overall, soil biota feedback tended to be lower, whereas nutrient feedback tended to be greater compared to the unsterilized control soil, suggesting that effects of antagonistic biota outweighed those of beneficial microbes in the biota treatment, and that plants optimized nutrient uptake when the soil microbiome was absent in the nutrient treatment. Furthermore, soils in the nutrient treatment trained by the legume crops (alfalfa and soy- bean) tended to provide the greatest positive feedback, emphasizing the impor- tant legacy of N2 fixers in crop rotation. Taken together, our data demonstrate how nutrients and soil biota can be integral to PSFs among crops, and that assessing PSFs under controlled conditions can serve as a basis to determine the most productive crop rotation sequences prior to field testing.info:eu-repo/semantics/publishedVersio

テキ リンユ シホン シジョウ ト キギョウ キンユウ タガ シュッパン 1999

書評(Book Review

Eigenarten des Japanischen Managements : Eine Interpretation als Principal-Agent-Problem

論文(Article

Corporate Governance Rating als Unternehmensbewertung

コーポレート・ガバナンス格付けは，いわゆる「格付け」そして「企業評価」の一種である。それは対象企業のコーポレート・ガバナンス・システムが，望ましい制度に比べてどの程度近いか，そのクオリティを評価するものである。ここではコーポレート・ガバナンス格付けとは何か，そしてその具体例をS ＆ P によるケースを見ながら考察していく。Corporate governance rating is a kind of corporate valuation. It attempts to assess the quality of corporate governance. This article tries to understand what is corporate governance rating, both theoretically and empirically as possible, by means of corporate governance score of S&P.Zusammenfassung Corporate Governance Rating ist eine Art von Unternehmensbewertung. Es versucht, die Qualität der Corporate Governance zu bewerten. In diesem Artikel wird versucht, zu verstehen, was Corporate Governance Rating ist, sowohl möglichst theoretisch als auch empirisch, mittels Corporate Governance Score von S&P