Progress in fluorescence detection and imaging technologies depends on the availability of fluorescent labels with strong light absorption/emission characteristics. We have synthesized intercalator ...dye arrays on a compact 3-dimensional DNA-tetrahedron nanostructure. The template tolerates the structural distortions introduced by intercalation and allows concentration of multiple fluorophores within a small volume, resulting in brightly fluorescent nanotags with effective extinction coefficients in the order of 106 M−1 cm−1. Efficient energy transfer from intercalated donor dyes to covalently attached acceptor dyes in the nanotags allows the emission wavelength to be shifted to the red relative to the excitation light, providing wavelength tunability. The compact nature of the supramolecular DNA tetrahedron also provides a protective medium for the fluorophores, leading to improved photostability and enhanced resistance to nuclease digestion, relative to one- or two-dimensional nanotags described previously.
Telomere shortening is a normal age-related process. However, premature shortening of telomeres in leukocytes--as has been reported in depression--may increase the risk for age-related diseases. ...While previous studies investigated telomere length in peripheral blood mononuclear cells (PBMCs) as a whole, this study investigated specific changes in the clonal composition of white blood cells of the adaptive immune system (CD4+ helper and CD8+ cytotoxic T lymphocytes, and CD20+ B lymphocytes).
Forty-four females with a history of unipolar depression were investigated and compared to fifty age-matched female controls. Telomere lengths were compared between three groups: 1) individuals with a history of depression but currently no clinically relevant depressive symptoms, 2) individuals with a history of depression with relevant symptoms of depression, and 3) healthy age-matched controls. Telomere length was assessed using quantitative fluorescence in situ hybridization (qFISH).
Both groups with a history of unipolar depression (with and without current depressive symptoms) showed significantly shorter telomeres in all three lymphocyte subpopulations. The effect was stronger in CD8+ and CD20+ cells than in CD4+ cells. Individuals with a history of depression and with (without) current symptoms exhibited a CD8+ telomere length shortening corresponding to an age differential of 27.9 (25.3) years.
A history of depression is associated with shortened telomeres in the main effector populations of the adaptive immune system. Shorter telomeres seem to persist in individuals with lifetime depression independently of the severity of depressive symptoms. CD8+ cytotoxic T cells and CD20+ B cells seem to be particularly affected in depression. The total number of depressive episodes did not influence telomere length in the investigated adaptive immune cell populations.
Aberrant mRNAs whose open reading frame (ORF) is truncated by the presence of a premature translation-termination codon (PTC) are recognized and degraded in eukaryotic cells by a process called ...nonsense-mediated mRNA decay (NMD). Here, we report the development of a reporter system that allows monitoring of NMD in mammalian cells by measuring the fluorescence of green fluorescent protein (GFP). The NMD reporter gene consists of a T-cell receptor-β minigene construct, in which the GFP-ORF was inserted such that the stop codon of GFP is recognized as PTC. The reporter mRNA is therefore subjected to NMD, resulting in a low steady-state mRNA level, an accordingly low protein level and hence a very low green fluorescence in normal, NMD-competent cells that express this reporter gene. We show that the inactivation of NMD by RNAi-mediated knockdown of the essential NMD factor hUpf1 or hSmg6 increases the NMD reporter mRNA level, resulting in a proportional increase of the green fluorescence that can be detected by flow cytometry, spectrofluorometry and fluorescence microscopy. With these properties, our GFP-based NMD reporter system could be used for large-scale screenings to identify NMD-inhibiting drugs or NMD-deficient mutant cells.
Human epidermal growth factor receptor 2 (HER2) is related to the pathogenesis and poor outcome of numerous types of carcinomas, including gastric carcinoma. Gastric cancer patients with HER2 ...positivity have become potential candidates for targeted therapy with trastuzumab.
We investigated 208 gastric cancer specimens using immunohistochemistry (IHC), fluorescence
hybridization and dual
hybridization (ISH). We also investigated the concordance between IHC and ISH. The correlation between HER2 status and various clinicopathological findings was also investigated.
In total, 15.9% (33/208) and 24.5% (51/208) of gastric cancers showed
gene amplification and protein overexpression, respectively. A high level of concordance between ISH and IHC analyses (91.3%, κ = 0.76) was found. A significant correlation between HER2 status and intestinal-type (p < .05) and differentiated carcinomas (p < .05) was also noted. The HER2 heterogeneity was high in gastric cancers; we found 68.8% phenotypic heterogeneity and 57.6% genotypic heterogeneity. Heterogeneity in HER2 protein expression and gene amplification showed a close association with diffuse histologic type and IHC 2+.
HER2 protein overexpression and gene amplification were detected in 24.5% and 15.9% of gastric cancer specimens, respectively. Intestinal-type showed a higher level of HER2 protein overexpression and gene amplification than diffuse type. HER2 status also showed a significant relationship with well- and moderately-differentiated carcinomas. The ratio of phenotypic and genotypic heterogeneity of HER2 was high in gastric carcinomas and was associated with HER2 IHC 2+ and diffuse histologic type.
Adult stem cells or residential progenitor cells are critical to maintain the structure and function of adult tissues (homeostasis) throughout the lifetime of an individual. Mis-regulation of stem ...cell proliferation and differentiation often leads to diseases including cancer, however, how wildtype adult stem cells and cancer cells respond to cellular damages remains unclear. We find that in the adult Drosophila midgut, intestinal stem cells (ISCs), unlike tumor intestinal cells, are resistant to various cellular damages. Tumor intestinal cells, unlike wildtype ISCs, are easily eliminated by apoptosis. Further, their proliferation is inhibited upon autophagy induction, and autophagy-mediated tumor inhibition is independent of caspase-dependent apoptosis. Interestingly, inhibition of tumorigenesis by autophagy is likely through the sequestration and degradation of mitochondria, as compromising mitochondria activity in these tumor models mimics the induction of autophagy and increasing the production of mitochondria alleviates the tumor-suppression capacity of autophagy. Together, these data demonstrate that wildtype adult stem cells and tumor cells show dramatic differences in sensitivity to cellular damages, thus providing potential therapeutic implications targeting tumorigenesis.
•Wildtype adult stem cells, unlike tumor cells, are resistant to cellular damages.•Apoptosis rapidly eliminate tumor cells, but not wildtype progenitors.•Autophagy induction significantly inhibits tumorigenesis.•Autophagy-mediated inhibition of tumorigenesis is not caspase-dependent.•Mitochondria affect autophagy-mediated inhibition of tumorigenesis.
Tissue engineering has revealed the potential to regenerate injured vocal folds, and identification of the most suitable seed cells has remained a hot topic of research. The aim of this study was to ...implant fibroblast-like cells differentiated from adipose-derived mesenchymal stem cells (ADSCs) in a canine acute vocal fold wound model. We then sought to characterize changes in the extracellular matrix (ECM) proteins of vocal fold lamina propria. For this purpose, ADSCs were induced to differentiate into fibroblasts under the regulation of connective tissue growth factor in vitro. Cell surface proteins were identified by immunofluorescence staining. Thirty vocal folds of 17 canines were injured by localized resection and injected with fibroblast-like cells (differentiated ADSCs, dADSCs), ADSCs or vocal fold fibroblasts (VFFs). The morphology of vocal folds was observed, and the characteristics of ECM protein components (collagen, elastin, hyaluronic acid, decorin and fibronectin) were evaluated by immunofluorescence staining from 15 days to 6 months following implantation. The results showed that in vitro, the dADSCs showed morphology and cell surface protein expression similar to those of VFFs. After implantation in vivo, the surfaces of the recipient vocal folds became almost smooth in the dADSCs and ADSCs groups at 6 months but remained slightly concave and stiff in the VFFs group. The elastin fluorescence intensity increased significantly and was maintained at a high level in the dADSCs group. The collagen fluorescence intensity increased slightly in the dADSCs and ADSCs groups, whereas it demonstrated a more irregular arrangement in the VFFs group. The fluorescence intensity of hyaluronic acid, decorin and fibronectin was similar between the three implanted groups. These results indicated that dADSCs may confer an advantage for vocal fold wound healing. Furthermore, dADSCs have the ability to secrete ECM components in vivo, particularly elastin, which may be beneficial for vocal fold vibration recovery.
A novel highly selective and sensitive fluorescent probe (NJ1) had been designed and synthesized for Cu2+ detection by fluorescence quenching mechanism, and then the enhancement of fluorescence ...intensity with the addition of hydrogen sulfide in complex NJ1Cu aqueous solution at physiological conditions were described. This “on–off–on” type fluorescence recognition system was a reversible process, which could be utilized to monitor copper ion and hydrogen sulfide based on a complex NJ1Cu formation–Cu2+ displacement approach. Importantly, this real-time recognition process of Cu2+ and hydrogen sulfide exhibited excellent anti-interference ability. In addition, this new fluorescent probe also has potential utility for Cu2+ and hydrogen sulfide detection in living cells, providing a potential tool for investigating copper ion and hydrogen sulfide in living systems or environment.
Display omitted
•NJ1 was a novel highly selective and sensitive fluorescent turn-off probe for Cu2+.•The fluorescence of this probe could be quickly recovered with the addition of H2S.•This monitoring system based on complex NJ1Cu formation–Cu2+ displacement approach.•NJ1 could be used for Cu2+ and hydrogen sulfide detection in living cells.
Anti-Stokes fluorescence from chlorophyll a Emura, Hidetoshi; Noji, Tomoyasu; Kondo, Masaharu ...
Journal of physics. Conference series,
05/2019, Volume:
1220, Issue:
1
Journal Article
Peer reviewed
Open access
Anti-Stokes fluorescence from chlorophyll a molecules dispersed in diethyl ether has been observed. From the excitation power dependence of the fluorescence spectrum, it is concluded that the ...anti-Stokes fluorescence appears via the linear optical process. To consider the relationship between the observed spectral shape and vibrational modes, the model spectral density has been determined based on the Raman spectrum and real-time coherent vibrational oscillation signals. The absorption spectrum observed in the experiment was well reproduced by the calculation, indicating the validity of the model spectral density. The involvement of the low-frequency vibrational modes in the anti-Stokes fluorescence process is discussed.
A new method of performing fluorescence correlation spectroscopy (FCS) measurements for mixtures of several fluorescent molecular species is introduced. It uses time-resolved fluorescence detection ...for separating the different FCS-contributions from the different species. This allows simultaneous and independent monitoring of the diffusion of several molecular species in one sample, or performing multi-label cross-correlation measurements. In this way, the proposed method is equivalent to dual- or multi-color FCS. However, it is simpler to implement experimentally, because it requires only single wavelength excitation and detection. This Letter outlines the theoretical basis and presents experimental results of the method.
PDF
