Pancreatic β Cell–specific Expression of Thioredoxin, an Antioxidative and Antiapoptotic Protein, Prevents Autoimmune and Streptozotocin-induced Diabetes

The cytotoxicity of reactive oxygen intermediates (ROIs) has been implicated in the destruction of pancreatic β cells in insulin-dependent diabetes mellitus (IDDM). Thioredoxin (TRX), a redox (reduction/oxidation)-active protein, has recently been shown to protect cells from oxidative stress and apoptosis. To elucidate the roles of oxidative stress in the development of autoimmune diabetes in vivo, we produced nonobese diabetic transgenic mice that overexpress TRX in their pancreatic β cells. In these transgenic mice, the incidence of diabetes was markedly reduced, whereas the development of insulitis was not prevented. Moreover, induction of diabetes by streptozotocin, an ROI-generating agent, was also attenuated by TRX overexpression in β cells. This is the first direct demonstration that an antioxidative and antiapoptotic protein protects β cells in vivo against both autoimmune and drug-induced diabetes. Our results strongly suggest that oxidative stress plays an essential role in the destruction of β cells by infiltrating inflammatory cells in IDDM

Supplementary material for the article: Fukushi, K.; Fujita, Y.; Nonogaki, J.; Tsujimoto, J.-I.; Hattori, T.; Inui, H.; Beškoski, V. P.; Hotta, H.; Hayashi, M.; Nakano, T. Capillary Zone Electrophoresis Determination of Fluoride in Seawater Using Transient Isotachophoresis. Analytical and Bioanalytical Chemistry 2018, 410 (6), 1825–1831. https://doi.org/10.1007/s00216-017-0838-0

Supplementary material for: [https://doi.org/10.1007/s00216-017-0838-0]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2083

Ryanodine receptor cluster fragmentation and redistribution in persistent atrial fibrillation enhance calcium release

In atrial fibrillation (AF), abnormalities in Ca(2+) release contribute to arrhythmia generation and contractile dysfunction. We explore whether RyR cluster ultrastructure is altered and is associated with functional abnormalities in AF.status: publishe

Supplementary material for the article: Fukushi, K.; Fujita, Y.; Nonogaki, J.; Tsujimoto, J.-I.; Hattori, T.; Inui, H.; Beškoski, V. P.; Hotta, H.; Hayashi, M.; Nakano, T. Capillary Zone Electrophoresis Determination of Fluoride in Seawater Using Transient Isotachophoresis. Analytical and Bioanalytical Chemistry 2018, 410 (6), 1825–1831. https://doi.org/10.1007/s00216-017-0838-0

Supplementary material for: [https://doi.org/10.1007/s00216-017-0838-0]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2083

The transcriptional co-activator LEDGF/p75 displays a dynamic scan-and-lock mechanism for chromatin tethering

Nearly all cellular and disease related functions of the transcriptional co-activator lens epithelium-derived growth factor (LEDGF/p75) involve tethering of interaction partners to chromatin via its conserved integrase binding domain (IBD), but little is known about the mechanism of in vivo chromatin binding and tethering. In this work we studied LEDGF/p75 in real-time in living HeLa cells combining different quantitative fluorescence techniques: spot fluorescence recovery after photobleaching (sFRAP) and half-nucleus fluorescence recovery after photobleaching (hnFRAP), continuous photobleaching, fluorescence correlation spectroscopy (FCS) and an improved FCS method to study diffusion dependence of chromatin binding, tunable focus FCS. LEDGF/p75 moves about in nuclei of living cells in a chromatin hopping/scanning mode typical for transcription factors. The PWWP domain of LEDGF/p75 is necessary, but not sufficient for in vivo chromatin binding. After interaction with HIV-1 integrase via its IBD, a general protein–protein interaction motif, kinetics of LEDGF/p75 shift to 75-fold larger affinity for chromatin. The PWWP is crucial for locking the complex on chromatin. We propose a scan-and-lock model for LEDGF/p75, unifying paradoxical notions of transcriptional co-activation and lentiviral integration targeting

Fano resonance in a multimode tapered fiber coupled with a microspherical cavity

Fano resonance in a tapered optical fiber in contact with a high-Q microsphere is demonstrated. Multimode waves propagating in a 2.3 µm diameter taper were coupled with a single whispering gallery mode of a 220 µm sphere, and their coherent interaction resulted in Fano resonance. The asymmetric line shapes of the transmission spectra changed periodically with scanning of the coupling position along the taper. The observed 24 µm period was due to modal dispersion in the tapered fiber

Experimental evaluation of diffusion constant in a thin polymer film by triplet lifetime analysis of single molecules

We propose a method for dynamically sensing oxygen concentration in a local nanoscale domain of a thin polymer film using histograms of photon interdetection times of single molecules. By temporally analyzing the histograms, a dynamical change in the triplet lifetime of single molecules in thin polymer films with different thicknesses can be measured with respect to the oxygen concentration in a gas cell. From the time lags for observing the triplet lifetime change in the histograms due to differences in the oxygen diffusion times in the films, we estimate the diffusion constants in a local nanoscale domain of films, which approximately corresponds to the reported values in the bulk film. Thus, we conclude that this method is applicable to in situ nanoscale environmental sensors with high spatial resolution in heterogeneous materials, such as polymer blends, biological cells, and thin-film devices

Recent advances in super-resolution fluorescence microscopy

Super-resolution fluorescence microscopy has attracted much attention in recent years as a technology which enables noninvasive observation of fine structures with more than lambda/10 resolution in far-field microscopy. The resolution is enhanced based on detection of a subpopulation of fluorescent molecules within a diffraction-limited area by switching off fluorescence in various ways. Many conventional and new dyes are applicable for realizing super-resolution fluorescence microscopy. Super-resolution fluorescence microscopy also makes new nanofabrication and recording techniques possible. In this review, the brief history of the field is overviewed, and the key features of individual microscopy techniques are explained in terms of photochemistry with most recent papers. Future outlook of super-resolution fluorescence microscopy is also discussed.status: publishe