High-Fidelity Assay Based on Turn-Off Fluorescence to Detect the Perturbations of Cellular Proteostasis.

The persistence of neurodegenerative diseases has necessitated the development of new strategies to monitor protein homeostasis (proteostasis). Previous efforts in our laboratory have focused on the development of fluorogenic strategies to observe the onset and progression of proteostatic stress. These works utilized solvatochromic and viscosity sensitive fluorophores to sense protein folded states, enabling stressor screening with an increase in the emission intensity upon aggregation.

Visualizing and Manipulating Biological Processes by Using HaloTag and SNAP-Tag Technologies.

Visualizing and manipulating the behavior of proteins is crucial to understanding the physiology of the cell. Methods of biorthogonal protein labeling are important tools to attain this goal. In this review, we discuss advances in probe technology specific for self-labeling protein tags, focusing mainly on the application of HaloTag and SNAP-tag systems.

A General Strategy to Enhance Donor-Acceptor Molecules Using Solvent-Excluding Substituents.

While organic donor-acceptor (D-A) molecules are widely employed in multiple areas, the application of more D-A molecules could be limited because of an inherent polarity sensitivity that inhibits photochemical processes. Presented here is a facile chemical modification to attenuate solvent-dependent mechanisms of excited-state quenching through addition of a β-carbonyl-based polar substituent. The results reveal a mechanism wherein the β-carbonyl substituent creates a structural buffer between the donor and the surrounding solvent.

Super-Resolution Optical Lithography with DNA.

We developed an efficient, versatile, and accessible super-resolution microscopy method to construct a nanoparticle assembly at a spatial resolution below the optical diffraction limit. The method utilizes DNA and a photoactivated DNA cross-linker. Super-resolution optical techniques have been used only as a means to make measurements below the light diffraction limit.

Modulation of Fluorescent Protein Chromophores To Detect Protein Aggregation with Turn-On Fluorescence.

We present a fluorogenic method to visualize misfolding and aggregation of a specific protein-of-interest in live cells using structurally modulated fluorescent protein chromophores. Combining photophysical analysis, X-ray crystallography, and theoretical calculation, we show that fluorescence is triggered by inhibition of twisted-intramolecular charge transfer of these fluorophores in the rigid microenvironment of viscous solvent or protein aggregates. Bioorthogonal conjugation of the fluorophore to Halo-tag fused protein-of-interests allows for fluorogenic detection of both misfolded and aggregated species in live cells.

The floating Meckel.

A 10-year-old girl was hospitalized because of abdominal pain and significant gastrointestinal bleeding for 3 days with hematocrit of 28% and hemoglobin of 6.1 mmol/L. Gastroscopy and abdominal ultrasound did not reveal any gastrointestinal abnormalities and parameters of coagulation were normal.