Physical chemistry in a single live cell: confocal microscopy

Amin, Md. Asif; Nandi, Shyamapada; Mondal, Prasenjit; Mahata, Tanushree; Ghosh, Surajit; Bhattacharyya, Kankan

doi:10.1039/c7cp02228j

Cited by 10 publications

(8 citation statements)

References 49 publications

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“…The present results therefore indicate that the macroscopic viscosity in the nucleus is lower than that in the cytoplasm and the dielectric constant of the environment is higher in the nucleus than that in the cytoplasm. These findings seem to be difficult to be obtained by other methods such as fluorescence and optical tomography, and we believe that the present result will become the basis of the evaluation of dynamics and molecular structures of biomolecules in cellular compartments in terms of macromolecular crowding. − The present result is consistent with the recent measurement of the refractive index or fluorescence dynamics of a dye in a cell. − The refractive index was shown to be smaller in the nucleus than that in the cytoplasm, suggesting a low concentration of organic molecules in the nucleus. , On the basis of the position of the emission maximum of an exogenous dye, the dielectric constant of the nucleus was suggested to be larger than that of the cytoplasm. − The viscosities of the nucleus and cytoplasm were also estimated to be ∼13 and ∼14.5 cP, respectively . It is noted that the present value is the average of the intracellular environment, which slightly fluctuates in seconds .…”

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confidence: 87%

Experimental Evaluation of the Density of Water in a Cell by Raman Microscopy

Takeuchi

Kajimoto

Nakabayashi

2017

J. Phys. Chem. Lett.

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We report direct observation of a spatial distribution of water molecules inside of a living cell using Raman images of the O-H stretching band of water. The O-H Raman intensity of the nucleus was higher than that of the cytoplasm, indicating that the water density is higher in the nucleus than that in the cytoplasm. The shape of the O-H stretching band of the nucleus differed from that of the cytoplasm but was similar to that of the balanced salt solution surrounding cells, indicating less crowded environments in the nucleus. The concentration of biomolecules having C-H bonds was also estimated to be lower in the nucleus than that in the cytoplasm. These results indicate that the nucleus is less crowded with biomolecules than the cytoplasm.

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confidence: 87%

Experimental Evaluation of the Density of Water in a Cell by Raman Microscopy

Takeuchi

Kajimoto

Nakabayashi

2017

J. Phys. Chem. Lett.

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“…In bulk water, solvation displays a time scale of ∼1 ps. − However, in many constrained environment (proteins, DNA, and biological cell), water exhibits a component of ca. 100–1000 ps. ,,− …”

Section: Resultsmentioning

confidence: 99%

“…18,19 These experiments are intermediate in complexity between studying an isolated protein in a solution 6,7 and that in a single live cell studied by super-resolution microscopy and time-resolved confocal microscopy. 25,26 In general, it is believed that crowding and the associated excluded volume effect accelerate protein folding and aggregation, enhance stability, and modulate enzyme activity.…”

Section: Introductionmentioning

confidence: 99%

“…Gruebele and co-workers investigated steric and nonsteric interactions in vitro by the crowding agent Ficoll 70 to understand the crowding effect inside a cell. , Pielak and co-workers studied the effect of reconstituted cytoplasm on the stability of a protein . Fluorescence correlation spectroscopy (FCS) has been used to monitor the effect of added polymer (poly(ethylene glycol)) on the size of a protein in an aqueous solution. − Chowdhury and co-workers studied FRET and solvation dynamics in a protein in the presence of several crowding agents such as dextran, poly(ethylene glycol), and other proteins. , These experiments are intermediate in complexity between studying an isolated protein in a solution , and that in a single live cell studied by super-resolution microscopy and time-resolved confocal microscopy. , In general, it is believed that crowding and the associated excluded volume effect accelerate protein folding and aggregation, enhance stability, and modulate enzyme activity.…”

Section: Introductionmentioning

confidence: 99%

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Structure, Activity, and Dynamics of Human Serum Albumin in a Crowded Pluronic F127 Hydrogel

et al. 2019

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Structure, activity, and dynamics of a plasma protein, human serum albumin (HSA), inside a crowded environment of F127 gel are studied by circular dichroism (CD), fluorescence correlation spectroscopy (FCS), and picosecond time-resolved fluorescence spectroscopy. For this purpose, the protein is covalently labeled by a maleimide dye, 7-(diethylamino)-3-(4-maleimidylphenyl)-4-methyl-coumarin (CPM). The circular dichroism (CD) spectra suggest that the protein is more structured in the gel reflecting about the biological activities of the protein. FCS results demonstrate that compared to that in bulk water (buffer solution), translational diffusion is about 59 times slower inside the F127 gel. This indicates higher translational friction (viscosity) sensed by the probe (CPM). On the contrary, rotational relaxation (and hence, rotational friction) is more or less similar in F127 gel and in bulk water. FCS results further indicate that the time scales of conformational relaxation of the protein are substantially slow inside the crowded environment of F127 gel. The fast component of conformational relaxation is retarded by ∼55 times, and the slow component by ∼20 times. Fluorescence maximum of CPM bound to HSA show a ∼5 nm red shift, implying that the microenvironment of the probe, CPM, is more polar inside the gel. Solvation dynamics of CPM-labeled HSA inside the gel (⟨τ s ⟩ ∼ 300 ps) is faster compared to that for the protein in bulk water (⟨τ s ⟩ ∼ 600 ps).

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“…32 Using absorption spectra to gauge the interface polarity often leads to dielectric constants lower than the bulk. For instance, ϵ ≃ 15 was reported for the cytoplasm of eukaryotic cells, whereas ϵ ≃ 65 was found for the cell nucleus 33 (ϵ ≃ 78 in the bulk). The lower effective dielectric constants are attributed to the prevalence of interfacial water in the crowded cellular medium.…”

Section: ■ Interface Susceptibilitymentioning

confidence: 99%

Effective Dielectric Constant of Water at the Interface with Charged C₆₀ Fullerenes

et al. 2019

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AZ 85287-1504 a) Dipolar susceptibility of interfacial water and the corresponding interface dielectric constant were calculated from numerical molecular dynamics simulations for neutral and charged states of buckminsterfullerene C 60 . Dielectric constants in the range 10-22, depending on temperature and solute charge, were found. The hydration water undergoes a structural crossover as a function of the solute charge. Its main signatures include the release of dangling O-H bonds pointing toward the solute and the change in the preferential orientations of hydration water from those characterizing hydrophobic to charged substrates. The interface dielectric constant marks the structural transition with a spike. The computational formalism adopted here provides direct access to interface susceptibility from configurations produced by computer simulations. The required property is the cross-correlation between the radial projection of the dipole moment of the solvation shell and the electrostatic potential of the solvent inside the solute.

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Physical chemistry in a single live cell: confocal microscopy

Cited by 10 publications

References 49 publications

Experimental Evaluation of the Density of Water in a Cell by Raman Microscopy

Experimental Evaluation of the Density of Water in a Cell by Raman Microscopy

Structure, Activity, and Dynamics of Human Serum Albumin in a Crowded Pluronic F127 Hydrogel

Effective Dielectric Constant of Water at the Interface with Charged C₆₀ Fullerenes

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Physical chemistry in a single live cell: confocal microscopy

Cited by 10 publications

References 49 publications

Experimental Evaluation of the Density of Water in a Cell by Raman Microscopy

Experimental Evaluation of the Density of Water in a Cell by Raman Microscopy

Structure, Activity, and Dynamics of Human Serum Albumin in a Crowded Pluronic F127 Hydrogel

Effective Dielectric Constant of Water at the Interface with Charged C60 Fullerenes

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Product

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Effective Dielectric Constant of Water at the Interface with Charged C₆₀ Fullerenes