scholarly journals Флуктуирующая флуоресценция одиночных центров окраски в кристаллах фторида лития

2022 ◽  
Vol 130 (1) ◽  
pp. 138
Author(s):  
В.П. Дресвянский ◽  
С.А. Зилов ◽  
Е.Ф. Мартынович
Keyword(s):  
Fluorescence Microscopy ◽  
Triplet State ◽  
Fluorescence Intensity ◽  
Room Temperature ◽  
Singlet State ◽  
Rotational Diffusion ◽  
Translational Diffusion ◽  
Color Centers ◽  
Confocal Fluorescence ◽  
Ground Singlet State

Single F2 and F3+- color centers in the LiF crystal were studied by confocal fluorescence microscopy. The time dependences of their fluorescence intensity were analyzed and statistically processed. Our studies show that, the F3+- color center, being photoexcited, is able enter the triplet state, while in ground (singlet) state it changes orientation with a frequency of 1.5 – 2 Hz at room temperature, due to reorientational diffusion, unlike the F2- center, which is reoriented only being in the triplet state. This subtype of rotational diffusion of the center does not lead to its translational diffusion.

scholarly journals Динамика накопления протопорфирина IX, индуцированного 5-аминолевулиновой кислотой в трех клеточных линиях разного происхождения

2021 ◽  
Vol 91 (1) ◽  
pp. 162
Author(s):  
Д.А. Горбенко ◽  
А.В. Белашов ◽  
Т.Н. Беляева ◽  
Е.С. Корнилова ◽  
И.К. Литвинов ◽  
...  
Keyword(s):  
Fluorescence Microscopy ◽  
Lung Adenocarcinoma ◽  
Cell Cultures ◽  
Fluorescence Intensity ◽  
Human Lung ◽  
Aminolevulinic Acid ◽  
Protoporphyrin Ix ◽  
3T3 Cells ◽  
Confocal Fluorescence ◽  
Lung Adenocarcinoma A549

By applying the confocal fluorescence microscopy, we investigated the dynamics of the synthesis and accumulation of protoporphyrin IX induced by 5-aminolevulinic acid (5-ALA) in three cell lines: malignant - human epithelial carcinoma HeLa and human lung adenocarcinoma A549 - and fibroblast-like immortalized mouse embryonic 3T3 cells. The accumulation of protoporphyrin IX in cell cultures was evaluated based on the analysis of its fluorescence intensity. The dynamics of changes in fluorescence intensity was studied depending upon the duration of cells incubation with 5-ALA and its concentration.

scholarly journals Confocal fluorescence microscopy for studying thapsigargin-induced bivalent-cation entry into B cells

1995 ◽  
Vol 305 (3) ◽  
pp. 1011-1015 ◽  
Author(s):  
Y Okamoto ◽  
T Furuno ◽  
T Hamano ◽  
M Nakanishi
Keyword(s):  
B Cells ◽  
Fluorescence Microscopy ◽  
Fluorescence Intensity ◽  
External Medium ◽  
Bivalent Cation ◽  
Fura 2 ◽  
Confocal Fluorescence ◽  
Fluorescence Images ◽  
Subsequent Addition ◽  
Ca2 Channels

We studied thapsigargin-induced bivalent-cation entry into antigen-specific B cells (TP67.21) with a confocal fluorescence microscope. Confocal fluorescence images of fluo-3-loaded B cells showed that thapsigargin-stimulated Ca2+ signals were transferred not only to the cytoplasm but also to the nucleus. In the absence of external Ca2+ ions, the free Ca2+ concentrations both in the cytosol and in the nucleus declined to basal levels by 5 min after addition of thapsigargin. However, subsequent addition of Ca2+ in the external medium made the fluo-3 (fura-2) fluorescence intensity rise, reflecting the fact that Ca2+ accumulated again in the nucleus as well as in the cytoplasm. Then, we added Ba2+ and Mn2+ instead of Ca2+, because Ba2+ and Mn2+ are known to enter via Ca2+ channels. The addition of Ba2+ and Mn2+ in the external medium quenched the fluo-3 fluorescence both in the nucleus and in the cytoplasm of B cells. This suggested the possibility that the increase in intranuclear Ca2+ after thapsigargin stimulation may come from the cytoplasm, not from the nuclear stores.

scholarly journals Protective Effect of Triptolide against Glomerular Mesangial Cell Proliferation and Glomerular Fibrosis in Rats Involves the TGF-β1/Smad Signaling Pathway

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yingjie Cao ◽  
Xinzhong Huang ◽  
Yaping Fan ◽  
Xiaolan Chen
Keyword(s):  
Fluorescence Microscopy ◽  
Protein Expression ◽  
Protective Effect ◽  
Fluorescence Intensity ◽  
Mesangial Cells ◽  
Control Group ◽  
Protein Expressions ◽  
Confocal Fluorescence ◽  
Group 2 ◽  
Ski Protein

Triptolide as a main active ingredient ofTripterygium wilfordiiis known to be exerting anti-inflammatory, marked immunosuppressive, and podocyte-protective effects. In this study, we investigated the protective effect of triptolide in kidney disease. Rat glomerular mesangial cells were randomly divided into three groups: (1) control group, (2) TGF-β1 (10 μg/mL) group, and (3) triptolide group (triptolide 10 μg/L + TGF-β1 10 μg/L). Sixty male Sprague-Dawley rats were randomly divided into three groups: (1) control group, (2) chronic serum sickness glomerulonephritis model group, and (3) triptolide (0.2 mg/kg·d) group. Reverse transcription PCR was used to assess Ski and Smad3 mRNA expression in the mesangial cells and renal tissues. Western blotting was used to determine Ski and Smad3 protein expressions. Laser confocal fluorescence microscopy was used to observe the subcellular localization of Smad3 and Ski proteins in the mesangial cells. Triptolide inhibited the TGF-β1-induced proliferation of mesangial cells. It significantly upregulated Ski protein expression and downregulated Smad3 mRNA and protein expressions in a time-dependent manner. Laser confocal fluorescence microscopy detected high Smad3 fluorescence intensity in the cytoplasm and low Smad3 and high Ski fluorescence intensity in the nucleus. By upregulating Ski protein expression triptolide decreased the extent of fibrosis by affecting the TGF-β1/Smad3 signaling pathway.

Two-photon excitation fluorescence microscopy in living systems

1993 ◽  
Vol 51 ◽  
pp. 154-155 ◽  
Author(s):  
David W. Piston
Keyword(s):  
Confocal Microscopy ◽  
Fluorescence Microscopy ◽  
Singlet State ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation fluorescence microscopy provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In our fluorescence experiments, the final excited state is the same singlet state that is populated during a conventional fluorescence experiment. Thus, the fluorophore exhibits the same emission properties (e.g. wavelength shifts, environmental sensitivity) used in typical biological microscopy studies. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10−5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

scholarly journals Analysis of Polyhydroxyalkanoates Granules in Haloferax mediterranei by Double-Fluorescence Staining with Nile Red and SYBR Green by Confocal Fluorescence Microscopy

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1582
Author(s):  
Verónica Cánovas ◽  
Salvador Garcia-Chumillas ◽  
Fuensanta Monzó ◽  
Lorena Simó-Cabrera ◽  
Carmen Fernández-Ayuso ◽  
...  
Keyword(s):  
Fluorescence Microscopy ◽  
Culture Media ◽  
Nile Red ◽  
Sybr Green ◽  
Confocal Fluorescence Microscopy ◽  
Fluorescence Staining ◽  
Haloferax Mediterranei ◽  
Optimized Protocol ◽  
Confocal Fluorescence ◽  
Pha Production

Haloferaxmediterranei is a haloarchaeon of high interest in biotechnology because it produces and mobilizes intracellular polyhydroxyalkanoate (PHA) granules during growth under stress conditions (limitation of phosphorous in the culture media), among other interesting metabolites (enzymes, carotenoids, etc.). The capability of PHA production by microbes can be monitored with the use of staining-based methods. However, the staining of haloarchaea cells is a challenging task; firstly, due to the high ionic strength of the medium, which is inappropriate for most of dyes, and secondly, due to the low permeability of the haloarchaea S-layer to macromolecules. In this work, Haloferax mediterranei is used as a halophilic archaeon model to describe an optimized protocol for the visualization and analysis of intracellular PHA granules in living cells. The method is based on double-fluorescence staining using Nile red and SYBR Green by confocal fluorescence microscopy. Thanks to this method, the capability of PHA production by new haloarchaea isolates could be easily monitored.

scholarly journals Electric Field Dependence of the Fluorescence Intensity of Solute Molecules and Fourth Order Effects

1985 ◽  
Vol 40 (9) ◽  
pp. 874-876
Author(s):  
Hilmar Bischof ◽  
Wolfram Baumann
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Field Dependence ◽  
Fourth Order ◽  
Fluorescence Intensity ◽  
Room Temperature ◽  
Order Effects ◽  
Electric Field Dependence ◽  
Total Fluorescence

Abstract The effect of an external electric field on the total fluorescence of solute molecules is studied up to fourth order theoretically, and is checked experimentally with 4´-N,N-dimethylamino- 4-nitrostilbene in dioxane at room temperature.

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