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Nature Chemistry Sep 2022The controlled switching of fluorophores between non-fluorescent and fluorescent states is central to every super-resolution fluorescence microscopy (nanoscopy)...
The controlled switching of fluorophores between non-fluorescent and fluorescent states is central to every super-resolution fluorescence microscopy (nanoscopy) technique, and the exploration of radically new switching mechanisms remains critical to boosting the performance of established, as well as emerging super-resolution methods. Photoactivatable dyes offer substantial improvements to many of these techniques, but often rely on photolabile protecting groups that limit their applications. Here we describe a general method to transform 3,6-diaminoxanthones into caging-group-free photoactivatable fluorophores. These photoactivatable xanthones (PaX) assemble rapidly and cleanly into highly fluorescent, photo- and chemically stable pyronine dyes upon irradiation with light. The strategy is extendable to carbon- and silicon-bridged xanthone analogues, yielding a family of photoactivatable labels spanning much of the visible spectrum. Our results demonstrate the versatility and utility of PaX dyes in fixed and live-cell labelling for conventional microscopy, as well as the coordinate-stochastic and deterministic nanoscopies STED, PALM and MINFLUX.
Topics: Fluorescent Dyes; Ionophores; Microscopy, Fluorescence; Silicon
PubMed: 35864152
DOI: 10.1038/s41557-022-00995-0 -
Animals : An Open Access Journal From... Mar 2022In this study, we present first data concerning the morphological observations of the orbital region, eye tunics, upper and lower eyelids, superficial gland of the third...
In this study, we present first data concerning the morphological observations of the orbital region, eye tunics, upper and lower eyelids, superficial gland of the third eyelid with the third eyelid, and lacrimal gland in captive adult male Asiatic black bear. The following research methods were used in the work: the eyeball morphometry, the orbital region description, macroscopic description, morphometric and histological analysis of the eye tunics and selected the accessory organs of the eye (Fontana-Masson, hematoxylin & eosin (H&E), Methyl-green-pyronin Y (MGP Y), Movat pentachrome, and picro-Mallory trichrome) as well as histochemical examination (PAS, AB pH 1.0, AB pH 2.5, AB pH 2.5/PAS and HDI). The eyeball of the Asiatic black bear was a spherical shape, while the periorbita was funnel/conical-shaped and the eye socket was of the open type. The cornea was absent of the Bowman's membrane similar to all domestic dogs and some wild dogs. There were palisades of Vogt in the corneal limbus epithelium similar to the Canidae. Degenerative choroidal tapetum lucidum similar to ranch mink (Mustelidae) has been found. The pupil was big and round in shape. The ciliary muscle, dilatator and sphincter muscle were well developed, similar to the pinnipeds. The lens was biconvex round, similar to the Canidae. The retina was composed similarly to the diurnal terrestrial carnivores. In both eyelids were observed very well-developed tarsal glands, ciliary glands and sebaceous glands. The orbital zone in the eyelids was characterized by lymphoid follicles, diffuse lymphocytes and specialized high endothelial venules. In the anterior palpebral margin of the upper eyelid, soft and short eyelashes were observed, while in the lower eyelids they were absent. The third eyelid was T-shaped and composed of the hyaline tissue, and it contained CALT, similar to that in Canidae. The superficial gland of the third eyelid was a multilobar alveolar branched complex with seromucous nature, while the lacrimal gland was also a multilobar acinar branched complex gland, but producing a mucous-serous secretion. The results of our research indicate that the features of the anatomy of the eye and orbital region in Asiatic black bear are also typical of the Ursidae family. Moreover, a detailed analysis of the morphological eye region may be useful in comparative studies and veterinary diagnostics in this bear species.
PubMed: 35405790
DOI: 10.3390/ani12070801 -
Pharmaceuticals (Basel, Switzerland) Mar 2023Tracers for bimodal optical imaging and positron emission tomography unite multiple advantages in a single molecule. Their tumor-specific uptake can be visualized after...
Tracers for bimodal optical imaging and positron emission tomography unite multiple advantages in a single molecule. Their tumor-specific uptake can be visualized after their PET activation by radiofluorination via PET/CT or PET/MRI allowing for staging or therapy planning, while their non-radioactive moiety additionally facilitates the visualization of malignant tissue during intraoperative fluorescence-guided surgery or in histological assessments. The silicon-bridged xanthene core offers the opportunity for radiofluorination with SiFA isotope exchange to obtain a small-molecule, PET-activatable NIR dye that can be linked to different target vectors. Herein, we demonstrate for the first time the PET-activation of a fluorinated silicon pyronine, belonging to a class of low-molecular-weight fluorescence dyes with a large Stokes shift (up to 129 nm) and solvent-dependent NIR dye properties, with a successful radiochemical conversion of 70%. The non-fluorinated pyronine precursor is easily accessible by a three-step sequence from commercially starting material with a 12% overall yield. Moreover, a library of seven unusually functionalized (by approximately 15 nm), red-shifted silicon rhodamines were synthesized in three- to four-step sequences and the optical properties of the novel dyes were characterized. It was also shown that the synthesized silicon rhodamine dyes can be easily conjugated by amide bond formation or 'click-reaction' approaches.
PubMed: 36986500
DOI: 10.3390/ph16030401 -
Nature Communications Jul 2021Multiplexed optical imaging provides holistic visualization on a vast number of molecular targets, which has become increasingly essential for understanding complex...
Multiplexed optical imaging provides holistic visualization on a vast number of molecular targets, which has become increasingly essential for understanding complex biological processes and interactions. Vibrational microscopy has great potential owing to the sharp linewidth of vibrational spectra. In 2017, we demonstrated the coupling between electronic pre-resonant stimulated Raman scattering (epr-SRS) microscopy with a proposed library of 9-cyanopyronin-based dyes, named Manhattan Raman Scattering (MARS). Herein, we develop robust synthetic methodology to build MARS probes with different core atoms, expansion ring numbers, and stable isotope substitutions. We discover a predictive model to correlate their vibrational frequencies with structures, which guides rational design of MARS dyes with desirable Raman shifts. An expanded library of MARS probes with diverse functionalities is constructed. When coupled with epr-SRS microscopy, these MARS probes allow us to demonstrate not only many versatile labeling modalities but also increased multiplexing capacity. Hence, this work opens up next-generation vibrational imaging with greater utilities.
Topics: Coloring Agents; HeLa Cells; Humans; Models, Chemical; Molecular Probes; Molecular Structure; Nonlinear Optical Microscopy; Optical Imaging; Pyronine; Spectrum Analysis, Raman; Vibration
PubMed: 34312393
DOI: 10.1038/s41467-021-24855-6 -
Iranian Journal of Pathology 2020Cell population and turnover are controlled by a balance between cell proliferation and apoptosis. Detection of apoptosis in oral cancer contributes to its better...
BACKGROUND & OBJECTIVE
Cell population and turnover are controlled by a balance between cell proliferation and apoptosis. Detection of apoptosis in oral cancer contributes to its better prognosis and improved management. This study aimed to quantify apoptotic cells in leukoplakia and oral squamous cell carcinoma (OSCC) using methyl green-pyronin (MGP) and hematoxylin and eosin (H & E) staining.
METHODS
The sample included a total of 130 subjects (comprising 108 males and 22 females). Formalin fixed and paraffin embedded tissues were used and categorized into three groups of normal oral mucosa (n=10), leukoplakia with dysplasia (n=60), and OSCC (n=60). The number of apoptotic cells and apoptotic index (AI) were calculated after staining with MGP and routine H & E stained slides.
RESULTS
MGP stained the condensed chromatin of apoptotic cells. Statistically significant difference (≤0.001) was observed among various study groups in terms of numbers of AI and apoptotic cells. Also, AI increased with increasing grades of dysplasia, and it was the highest in well differentiated OSCC. Results were statistically significant in both H & E and MGP stained sections (≤0.001). A good correlation was found between MGP and H & E staining results.
CONCLUSION
MGP is more specific and can lead to intense staining for chromatin in apoptotic cells. Accordingly, it can provide a good alternative to H&E in identifying apoptotic cells.
PubMed: 32754214
DOI: 10.30699/ijp.2020.107263.2115 -
Virology Journal Aug 2021Canine distemper caused by canine distemper virus that belongs to the Morbillivirus genus of the Paramyxoviridae family is still a global epidemic significant infectious...
BACKGROUND
Canine distemper caused by canine distemper virus that belongs to the Morbillivirus genus of the Paramyxoviridae family is still a global epidemic significant infectious disease, especially in pet dogs in China and serious harm to the development of the dog industry. It has been known that apoptosis caused by the canine distemper virus can show in culture cells, lymphoid tissues, and the cerebellum. However, its occurrence in brain tissue cells remains unclear. To investigate the relationship among canine distemper infecting brain tissues, apoptosis in brain tissue cells, and demyelinating pathogenesis was investigated.
METHODS
16 naturally infected dogs that exhibited clinical signs of CD and tested positive for the anti-CDV monoclonal antibody and six healthy dogs that served as the control, were used in the research. Brain specimens were divided into the cerebrum, brain stem, and cerebellum embedded in paraffin and made the sections respectively. Approximately 5 µm-thick sections were stained by hematoxylin-eosin, methyl green pyronin, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling technique, and immunohistochemistry. CDV nucleocapsid protein was detected by immune streptavidin-biotinylated peroxidase complex.
RESULTS
Alterations in the brain tissues of CDV-infected dogs involved both various cells and nerve fibers. CDV had varying degrees of cytotropism to all brain tissue cells; apoptosis also occurred in all brain cells, especially in the endothelia of cerebral vessels, astrocytes, oligodendrocytes, and ependymal cells, the more serious infection, the more obvious apoptosis. Serious infections also involved the pyramidal and Purkinje cells. The nervous fibers exhibited demyelinating lesions (showed small multifocal vacuole), and some axonal neuron atrophy gradually disappeared (formed large vacuole).
CONCLUSIONS
Apoptosis in brain tissue cells was mainly related to the propagation path and cytotropism of CDV. The apoptosis of astrocytes, oligodendrocytes, and some neurons may play a significant role in the demyelinating pathogenesis in dogs with acute canine distemper. A lot of diverse nervous signs shown in the clinic may be related to different neuron apoptosis.
Topics: Animals; Apoptosis; Astrocytes; Brain; Distemper; Distemper Virus, Canine; Dogs; Neurons; Oligodendroglia
PubMed: 34384430
DOI: 10.1186/s12985-021-01635-8 -
The Journal of Physical Chemistry... Sep 2022The pyronin class of fluorophores serves a critical role in numerous imaging applications, particularly involving preferential staining of RNA through base pair...
The pyronin class of fluorophores serves a critical role in numerous imaging applications, particularly involving preferential staining of RNA through base pair intercalation. Despite this important role in molecular staining applications, the same set of century-old pyronins (i.e., pyronin Y (PY) and pyronin B (PB)), which possess relatively low fluorophore brightness, are still predominantly being used due to the lack of methodology for generating enhanced variants. Here, we use TD-DFT calculations of interconversion energies between structures on the S surface as a preliminary means to evaluate fluorophore brightness for a proposed set of pyronins containing variable substitution patterns at the 2, 3, 6, and 7 positions. Using a nucleophilic aromatic substitution/hydride addition approach, we synthesized the same set of pyronins and demonstrate that quantum-mechanical computations are useful for predicting fluorophore performance. We produced the brightest series of pyronin fluorophores described to date, which possess considerable gains over PY and PB.
Topics: Fluorescent Dyes; Molecular Structure; Pyronine; RNA; Staining and Labeling
PubMed: 36040023
DOI: 10.1021/acs.jpclett.2c02287 -
Bioorganic & Medicinal Chemistry Letters Jul 20249-cyanopyronin is a promising scaffold that exploits resonance Raman enhancement to enable sensitive, highly multiplexed biological imaging. Here, we developed...
9-cyanopyronin is a promising scaffold that exploits resonance Raman enhancement to enable sensitive, highly multiplexed biological imaging. Here, we developed cyano-Hydrol Green (CN-HG) derivatives as resonance Raman scaffolds to expand the color palette of 9-cyanopyronins. CN-HG derivatives exhibit sufficiently long wavelength absorption to produce strong resonance Raman enhancement for near-infrared (NIR) excitation, and their nitrile peaks are shifted to a lower frequency than those of 9-cyanopyronins. The fluorescence of CN-HG derivatives is strongly quenched due to the lack of the 10th atom, unlike pyronin derivatives, and this enabled us to detect spontaneous Raman spectra with high signal-to-noise ratios. CN-HG derivatives are powerful candidates for high performance vibrational imaging.
Topics: Spectrum Analysis, Raman; Molecular Structure; Vibration; Nitriles
PubMed: 38636718
DOI: 10.1016/j.bmcl.2024.129757 -
Organic Letters Jan 2020A synthesis of the carbopyronine dye Carboxy ATTO 647N from simple materials is reported. This route proceeds in 11 forward steps from 3-bromoaniline with the key...
A synthesis of the carbopyronine dye Carboxy ATTO 647N from simple materials is reported. This route proceeds in 11 forward steps from 3-bromoaniline with the key xanthone intermediate formed using a new oxidation methodology. The step utilizes an oxidation cycle with base, water, iodine, and more than doubles the yield of the standard permanganate oxidation methodology, accessing gram-scale quantities of this late-stage product. From this, Carboxy ATTO 647N was prepared in only four additional steps. This facile route to a complex fluorophore is expected to enable further studies in fluorescence imaging.
Topics: Fluorescent Dyes; Molecular Structure; Oxidation-Reduction; Pyronine; Xanthones
PubMed: 31825225
DOI: 10.1021/acs.orglett.9b03981 -
Pharmaceutics Nov 2021Pharmaceutical technology offers various dosage forms that can be applied interdisciplinary. One of them are spherical pellets which could be utilized as a carrier in...
Utilization of Pharmaceutical Technology Methods for the Development of Innovative Porous Metasilicate Pellets with a Very High Specific Surface Area for Chemical Warfare Agents Detection.
Pharmaceutical technology offers various dosage forms that can be applied interdisciplinary. One of them are spherical pellets which could be utilized as a carrier in emerging second-generation detection tubes. This detection system requires carriers with high specific surface area (SSA), which should allow better adsorption of toxic substances and detection reagents. In this study, a magnesium aluminometasilicate with high SSA was utilized along with various concentrations of volatile substances (menthol, camphor and ammonium bicarbonate) to increase further the carrier SSA after their sublimation. The samples were evaluated in terms of physicochemical parameters, their morphology was assessed by scanning electron microscopy, and the Brunauer-Emmett-Teller (BET) method was utilized to measure SSA. The samples were then impregnated with a detection reagent o-phenylenediamine-pyronine and tested with diphosgene. Only samples prepared using menthol or camphor were found to show red fluorescence under the UV light in addition to the eye-visible red-violet color. This allowed the detection of diphosgene/phosgene at a concentration of only 0.1 mg/m in the air for samples M20.0 and C20.0 with their SSA higher than 115 m/g, thus exceeding the sensitivity of the first-generation DT-12 detection tube.
PubMed: 34834274
DOI: 10.3390/pharmaceutics13111860