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Results for “Fluorescence Microscopy”

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At least 235 records · Page 13Linked to original sources
PubMed1977

[Fluorescence microscopy demonstration of mitochondria in tissue culture cells using berberine].

The possibility of fluorescence microscopical examination of mitochondria in living animal cells using fluorochrome berberine sulphate is shown. At concentrations of 30--50 g per ml the chemical is accumulated selectively in mitochondria of living cells. The specificity of berberine sulphate accumulation in mitochondria was shown by comparative phase contrast and fluorescence microscopy. The advantages of the method is its high sensitivity and simplicity, especially when mitochondria can not be examined by the phase contrast microscopy.

Animals↗
PubMed2005

Lactone cleavage reaction kinetics of rhodamine dye at liquid/liquid interfaces studied by micro-two-phase sheath flow/two-photon excitation fluorescence microscopy.

Two-photon excitation fluorescence microscopy was combined with the two-phase microflow system in order to measure the fast interfacial reaction rate at liquid/liquid interfaces. The lactone cleavage kinetics of octadecylrhodamine B (C(18)RB) at the toluene/water and heptane/water interfaces was studied by this new method. The organic solution containing the nonfluorescent lactone of C(18)RB was made to flow as an inner flow with an aqueous outer sheath flow. The diameter of the inner flow was <20 microm. A focused fundamental beam of a Ti:sapphire pulse laser of 780 nm was irradiated to the interface, and emitted fluorescence from the fluorescent product was detected by a charge-coupled device (CCD) camera or a streakscope. The increase in the concentration of the fluorescent form of C(18)RB was measured along the interface of the inner flow of the toluene/water and heptane/water systems for 80 micros just after the contact of two phases. The analysis made by the time-dependent Langmuir adsorption model with the aid of the digital simulation method gave the cleavage reaction rate constants of the lactone form of C(18)RB at the liquid/liquid interfaces.

Journal Article↗
PubMed1995

Flow injection fluorescence microscopy applied to a rapid cell surface immunoassay.

A perfusion system for fluorescence microscopy that utilized a flow injection system was developed and used to study cell surface antibody binding on viable cells grown in monolayer cultures on coverslips. A polyclonal cell-specific antiserum used to probe the cell surface was monitored by indirect immunofluorescence. The flow injection system was completely automatic and allowed controlled perfusion of cell surfaces with the desired sequence of antibodies. The individual steps of the indirect assay were studied to determine the binding behavior of the primary cell surface antibody, the labeled second antibody, and control of nonspecific binding. Under stopped flow conditions, the second antibody was maximally bound within 10 min, while constant mixing of the second antibody solution over the cells resulted in maximal binding within as little as 6 min. A primary antibody contact time of 2 min followed by a wash and then exposure to the second antibody for 2 min showed that this fast automated procedure could distinguish specific from nonspecific binding of cell surface antibodies to the same set of cells for several repeated exposures. The flow injection fluorescence microscopy system can be automated to allow screening for cell surface antibodies and to study their interaction with specific cell surface antigens.

Animals↗
PubMed2003

Molecular packing of lysozyme, fibrinogen, and bovine serum albumin on hydrophilic and hydrophobic surfaces studied by infrared-visible sum frequency generation and fluorescence microscopy.

Infrared-visible sum frequency generation (SFG) vibrational spectroscopy, in combination with fluorescence microscopy, was employed to investigate the surface structure of lysozyme, fibrinogen, and bovine serum albumin (BSA) adsorbed on hydrophilic silica and hydrophobic polystyrene as a function of protein concentration. Fluorescence microscopy shows that the relative amounts of protein adsorbed on hydrophilic and hydrophobic surfaces increase in proportion with the concentration of protein solutions. For a given bulk protein concentration, a larger amount of protein is adsorbed on hydrophobic polystyrene surfaces compared to hydrophilic silica surfaces. While lysozyme molecules adsorbed on silica surfaces yield relatively similar SFG spectra, regardless of the surface concentration, SFG spectra of fibrinogen and BSA adsorbed on silica surfaces exhibit concentration-dependent signal intensities and peak shapes. Quantitative SFG data analysis reveals that methyl groups in lysozyme adsorbed on hydrophilic surfaces show a concentration-independent orientation. However, methyl groups in BSA and fibrinogen become less tilted with respect to the surface normal with increasing protein concentration at the surface. On hydrophobic polystyrene surfaces, all proteins yield similar SFG spectra, which are different from those on hydrophilic surfaces. Although more protein molecules are present on hydrophobic surfaces, lower SFG signal intensity is observed, indicating that methyl groups in adsorbed proteins are more randomly oriented as compared to those on hydrophilic surfaces. SFG data also shows that the orientation and ordering of phenyl rings in the polystyrene surface is affected by protein adsorption, depending on the amount and type of proteins.

Adsorption↗
PubMed1991

The cytological diagnosis of Pneumocystis carinii by fluorescence microscopy of Papanicolaou stained bronchoalveolar lavage specimens.

In a retrospective and prospective analysis fluorescence microscopy of Papanicolaou stained bronchoalveolar lavage specimens has been applied to the diagnosis of Pneumocystis carinii (PC) in routine cytology. The pneumocysts presented as circular structures of 5 microns in diameter and of brilliant green-yellow fluorescence surrounding two mirror image reniform structures. Fluorescent inclusions of 1-3 microns diameter within the alveolar macrophages could be identified as remnants of pneumocysts by a follow-up of all steps of degradation ending in very small irregular granules. By applying both criteria, i.e. pneumocysts with reniform bodies and degradation inclusions within macrophages, Pneumocystis carinii pneumonitis (PCP) could be detected in 100% of cases. Transbronchial biopsy permitted the correct diagnosis in only 65.2% of cases. Retrospective analysis of slides is possible after a long period as no significant loss of fluorescence occurs after 4 years. Thus fluorescence microscopy permits the diagnosis of Pneumocystis carinii without any additional staining or loss of time.

Bronchoalveolar Lavage Fluid↗
PubMed1997

A novel technique for mapping the lipid composition of atherosclerotic fatty streaks by en face fluorescence microscopy.

We introduce here a new fluorescence microscopy technique for en face analysis of the atherosclerotic fatty streaks (FS). This technique is semiquantitative and has the sensitivity and resolution to map lipids to individual cells in FS less than 100 microns in diameter. New Zealand White rabbits were fed an atherogenic diet for up to 26 weeks. Aortas were fixed in formalin and stained en bloc with the fluorescent dyes Nile red and filipin. Fluorescent staining was validated by correlating microfluorimetric and biochemical measurements of the lipid content in FS. To determine the cell types associated with the different staining patterns, FS were also evaluated by transmission electron microscopy (TEM) and immunohistochemistry (IH). Correlation of microfluorimetry, TEM, IH, and biochemical data indicated that regions rich in non-esterified cholesterol stained with filipin and fluoresced blue owing to accumulations of lipid vesicles and/or cholesterol crystals. Regions rich in neutral and polar lipids stained with Nile red and fluoresced yellow or orange, respectively, owing to accumulations of lipids in both macrophages and smooth muscle cells (SMC). Digital overlays of the filipin and Nile red images revealed that larger lesions (> 0.5 mm diameter) had a "nested" distribution of lipids, with a blue (filipin) fringe surrounding an orange (Nile red) fringe surrounding a yellow (Nile red) center.

Animals↗
PubMed2001

Fluorescence microscopy of single viral capsids.

To build a foundation for the single-molecule fluorescence microscopy of protein complexes, the present study achieved fluorescence microscopy of single, nucleic acid-free protein capsids of bacteriophage T7. The capsids were stained with Alexa 488 (green emission). Manipulation of the capsids' thermal motion was achieved in three dimensions. The procedure for manipulation included embedding the capsids in an agarose gel. The data indicate that the thermal motion of capsids is reduced by the sieving of the gel. The thermal motion can be reduced to any desired level. A semilogarithmic plot of an effective diffusion constant as a function of gel concentration is linear. Single, diffusing T7 capsids were also visualized in the presence of single DNA molecules that had been both stretched and immobilized by gel-embedding. The DNA molecules were stained with ethidium (orange emission). This study shows that single-molecule (protein and DNA) analysis is possible for both packaging of DNA in a bacteriophage capsid and other events of DNA metabolism. The major problem is the maintenance of biochemical activity.

Bacteriophage T7↗