Genetically encoded tags for direct synthesis of EM-visible gold nanoparticles in cells.

Genetically encoded tags for single-molecule imaging in electron microscopy (EM) are long-awaited. Here, we report an approach for directly synthesizing EM-visible gold nanoparticles (AuNPs) on cysteine-rich tags for single-molecule visualization in cells. We first uncovered an auto-nucleation suppression mechanism that allows specific synthesis of AuNPs on isolated tags. Next, we exploited this mechanism to develop approaches for single-molecule detection of proteins in prokaryotic cells and achieved an unprecedented labeling efficiency. We then expanded it to more complicated eukaryotic cells and successfully detected the proteins targeted to various organelles, including the membranes of endoplasmic reticulum (ER) and nuclear envelope, ER lumen, nuclear pores, spindle pole bodies and mitochondrial matrices. We further implemented cysteine-rich tag-antibody fusion proteins as new immuno-EM probes. Thus, our approaches should allow biologists to address a wide range of biological questions at the single-molecule level in cellular ultrastructural contexts.

Author Correction: Genetically encoded tags for direct synthesis of EM-visible gold nanoparticles in cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Highly Fluorescent Nanotubes with Tunable Diameter and Wall Thickness Self-Assembled from Asymmetric Perylene Diimides.

Highly fluorescent bilayer-walled and monolayer-walled nanotubes are assembled from elaborately designed asymmetric perylene diimide (PDI) molecules. The diameter of bilayer-walled nanotubes increases with the size of the branched substituents at the meta-position of the phenyl moiety of PDI molecules, whereas that of monolayer-walled nanotubes remains unchanged regardless of the size of branched substituents.

Can venture capital shareholding improve M&A performance? An empirical study based on Chinese GEM-listed companies.

Existing studies have explored the impact of venture capital shareholding on the GEM-listed companies before and after listing from multiple perspectives. However, there has been limited research on the influence of venture capital shareholding on these companies' mergers and acquisitions(M&A) activities and performance. Additionally, two conflicting research findings have been presented in limited relevant studies. In order to clarify the mechanism by which venture capital shareholding affects M&A activities and performance of GEM-listed companies and verify existing research conclusions, this paper takes 468 M&A events completed by the acquirer of China's GEM-listed companies between 2014 and 2016 as samples to explore venture capital shareholding's effects on the M&A performance of GEM-listed enterprises. The empirical findings demonstrate that GEM-listed enterprises with venture capital shareholding perform significantly better in terms of short-term and long-term M&A performance than those without; with the increase in venture capital shareholding ratio, the short-term M&A performance of GEM-listed enterprises has remarkably improved, but the long-term M&A performance does not show obvious correlation; joint investment of venture capital can significantly improve the short-term M&A performance of GEM-listed enterprises, but it has no substantial influence on long-term M&A performance. Based on further analysis of the empirical study, it is concluded that the common one-share ownership structure of GEM-listed enterprises is not conducive to the play of the monitoring function of venture capital, and the insufficient incentives and free-riding thinking also weaken the motivation and input of some venture capital shareholders to provide value-added services. This study systematically elucidates the mechanism and impact of venture capital shareholding on the M&A performance of GEM-listed companies, addressing the shortcomings in existing research. It is conducive for GEM-listed companies to gain a rational understanding and effectively leverage the active role of venture capital shareholders in M&A activities.

Fingerprint Detection and Differentiation of Gas-phase Amines Using a Fluorescent Sensor Array Assembled from Asymmetric Perylene Diimides.

A series of structurally analogous PDIs were fabricated and used as fluorescent sensor arrays. Adjustment of the molecular electron-donating ability and polarity (i.e., chemical structure) was found to greatly influence the fluorescent quenching by different types of amines. Moreover, the sensor array displayed high sensitivity to amine vapors and allowed the fingerprint differentiation of different species.