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1

Chlorination effect on the fluorescence of nucleic acid staining dyes  

Microsoft Academic Search

An alternative to culture methods for the control of drinking water disinfection would use fluorescent dyes that could evidence the nucleic acid damages provoked by sodium hypochlorite treatment. The two dyes selected in this study, SYBR Green II RNA gel stain and TOTO-1 iodide, efficiently stain nucleic acids (DNA and RNA) and quite poorly the other biomolecules considered (Bovine serum

M. H. Phe; M. Dossot; J. C. Block

2004-01-01

2

Optimization of staining conditions for microalgae with three lipophilic dyes to reduce precipitation and fluorescence variability.  

PubMed

When the fluorescence signal of a dye is being quantified, the staining protocol is an important factor in ensuring accuracy and reproducibility. Increasingly, lipophilic dyes are being used to quantify cellular lipids in microalgae. However, there is little discussion about the sensitivity of these dyes to staining conditions. To address this, microalgae were stained with either the lipophilic dyes often used for lipid quantification (Nile Red and BODIPY) or a lipophilic dye commonly used to stain neuronal cell membranes (DiO), and fluorescence was measured using flow cytometry. The concentration of the cells being stained was found not to affect the fluorescence. Conversely, the concentration of dye significantly affected the fluorescence intensity from either insufficient saturation of the cellular lipids or formation of dye precipitate. Precipitates of all three dyes were detected as events by flow cytometry and fluoresced at a similar intensity as the chlorophyll in the microalgae. Prevention of precipitate formation is, therefore, critical to ensure accurate fluorescence measurement with these dyes. It was also observed that the presence of organic solvents, such as acetone and dimethyl sulfoxide (DMSO), were not required to increase penetration of the dyes into cells and that the presence of these solvents resulted in increased cellular debris. Thus, staining conditions affected the fluorescence of all three lipophilic dyes, but Nile Red was found to have a stable fluorescence intensity that was unaffected by the broadest range of conditions and could be correlated to cellular lipid content. PMID:22648989

Cirulis, Judith T; Strasser, Bridget C; Scott, John A; Ross, Gregory M

2012-07-01

3

Simultaneous staining with three fluorescent dyes of minute plankters on an agarose gel filter  

NASA Astrophysics Data System (ADS)

A new method, employing an agarose gel filter and triple staining with fluorescent dyes, was developed for observation and enumeration of planktonic microorganisms (0.2-20 ?m in size range) from a variety of niches in the marine ecosystem. Dansyl chloride was used to stain the cell-surface proteins, Calcofluor white was used to stain cellulose and chitin, and DAPI was used to stain DNA. The stained specimens also could be examined by transmission light microscopy.

Hara, Shigemitsu; Tanoue, Eiichiro

1989-11-01

4

Fluorescent dye-based simple staining for in vivo micronucleus test with flow cytometer.  

PubMed

Flow cytometry (FCM) has become known as a useful tool for examining numerous cells in a micronucleus test in a short time. To successfully count micronuclei, immature erythrocytes and micronuclei need to be specifically stained and CD71-based FCM, with anti-CD71 antibody for immature erythrocytes and propidium iodide (PI) for micronuclei is a widely accepted tool. Because staining with fluorescent dyes may be much simpler compared to immunostaining, attempts are being made to develop a fluorescent dye-based FCM (FD-FCM). The aim of this study was to provide a practical FD-FCM method. Peripheral blood (PB) erythrocytes and bone marrow (BM) erythrocytes were obtained from rats treated with cyclophosphamide at a dose of 20mg/kg for two days. Nucleic cells of BM samples were eliminated using a cellulose column. Then erythrocytes were fixed, stained with Hoechst 33258 and PI and examined with FCM. Mean FD-FCM values of micronucleated immature erythrocytes in PB and BM were respectively 110% and 77% of the values obtained by microscopy. Percentages of mean immature erythrocyte values by FCM to those by microscopy were 74% and 94%. These data suggest that the simple method, composed of column purification of erythrocytes, methanol fixation, fluorescent dye staining and FCM, was useful for automated scoring in micronucleus testing of rat BM and PB. PMID:23291344

Harada, Asako; Matsuzaki, Kaori; Takeiri, Akira; Tanaka, Kenji; Mishima, Masayuki

2013-03-18

5

Heterogeneous staining: a tool for studies of how fluorescent dyes affect the physical properties of DNA  

PubMed Central

The commonly used fluorescent dye YOYO-1 (YOYO) has, using bulk techniques, been demonstrated to stain DNA heterogeneously at substoichiometric concentrations. We here, using nanofluidic channels and fluorescence microscopy, investigate the heterogeneous staining on the single DNA molecule level and demonstrate that the dye distribution is continuous. The equilibration of YOYO on DNA is extremely slow but can be accelerated by increasing the ionic strength and/or the temperature. Furthermore, we demonstrate how to use the heterogeneous staining as a tool for detailed and time-efficient studies of how fluorescent dyes affect the physical properties of DNA. We show that the relative increase in extension of DNA with increasing amount of YOYO bound is higher at low ionic strengths and also extrapolate the extension of native DNA. Our study reveals important information on how YOYO affects the physical properties of DNA, but it also has broader applications. First, it reveals how cationic intercalators, such as potential DNA drugs, affect DNA under strong confinement. Second, the strategy of using heterogeneous staining is of general use for single molecule studies of DNA interacting with proteins or ligands.

Nyberg, Lena; Persson, Fredrik; Akerman, Bjorn; Westerlund, Fredrik

2013-01-01

6

Development of Pathological Diagnostics of Human Kidney Cancer by Multiple Staining Using New Fluorescent Fluolid Dyes  

PubMed Central

New fluorescent Fluolid dyes have advantages over others such as stability against heat, dryness, and excess light. Here, we performed simultaneous immunostaining of renal tumors, clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, acquired cystic disease-associated RCC (ACD-RCC), and renal angiomyolipoma (AML), with primary antibodies against Kank1, cytokeratin 7 (CK7), and CD10, which were detected with secondary antibodies labeled with Fluolid-Orange, Fluolid-Green, and Alexa Fluor 647, respectively. Kank1 was stained in normal renal tubules, papillary RCC, and ACD-RCC, and weakly or negatively in all other tumors. CK7 was positive in normal renal tubules, papillary RCC, and ACD-RCC. In contrast, CD10 was expressed in renal tubules and clear cell RCC, papillary RCC, AML, and AC-RCC, and weakly in chromophobe RCC. These results may contribute to differentiating renal tumors and subtypes of RCCs. We also examined the stability of fluorescence and found that fluorescent images of Fluolid dyes were identical between a tissue section and the same section after it was stored for almost three years at room temperature. This indicates that tissue sections can be stored at room temperature for a relatively long time after they are stained with multiple fluorescent markers, which could open a door for pathological diagnostics.

Wuxiuer, Dilibaier; Zhu, Yun; Ogaeri, Takunori; Mizuki, Keiji; Kashiwa, Yuki; Nishi, Kentaro; Isobe, Shin-ichiro; Aoyagi, Tei-ichiro; Kiyama, Ryoiti

2014-01-01

7

A fast and cost-effective methodology for Fonsecaea pedrosoi ATCC46428 staining using ESIPT fluorescent dyes.  

PubMed

The microscopic morphology of Fonsecaea pedrosoi ATCC46428 was observed using two benzazole derivatives, 2-(2'-hydroxyphenyl)benzoxazole and 2-(5'-amino-2'-hydroxyphenyl)benzoxazole, which emit intense fluorescence by a proton transfer mechanism in the electronically excited state (ESIPT). The cell surface could be successfully stained with fluorescent dye solutions of 10 microM-10 mM using two different fast and cost-effective procedures. At these concentrations, any structure or dye crystallization could be observed. Concerning the external microstructural details, only the amino derivative allowed the differentiation between hyphae and conidia. These dyes presented some advantages comparing to commercial dyes, since the stained cells showed high chemical, thermal and photochemical stability during the experiments and also after several months of storage at room temperature and normal light exposition. Procedure 1 presented the advantage to be used when heating can change the chemical or biochemical cell composition. On the other hand Procedure 2 showed to be useful as a routine methodology for cells staining. The results allowed to propose a simple and highly sensitive assay to study the F. pedrosoi micromorphology by epifluorescence microscopy. This methodology can probably be extended for other fungi of clinical interest. PMID:20385502

Corbellini, Valeriano Antonio; Scroferneker, Maria Lúcia; Carissimi, Mariana; Rodembusch, Fabiano Severo; Stefani, Valter

2010-06-01

8

Comparative analysis of the DNA staining efficiencies of different fluorescent dyes in preparative agarose gel electrophoresis.  

PubMed

Ethidium bromide (EB) is a mutagen and toxin that is widely used in the laboratory for visualization of nucleic acids. Safer nucleic acid stains, such as SYBR Gold, SYBR Green, GoldView, GeneFinder, and GoldStar, have been developed. However, there has been no systematic comparative analysis of the staining efficiencies of these dyes. In the present study, SYBR Gold, SYBR Green I, GoldView and EB were compared. Although both SYBR Gold and SYBR Green alter electrophoretic mobility and thus DNA size estimates, they are cost-effective alternatives to EB. SYBR Gold was more sensitive than SYBR Green I at detecting short fragments, but 50-bp bands were clearly visible using either dye when visualized with a long integration time. SYBR Gold or SYBR Green I are sensitive and relatively safe alternatives to EB. In our laboratory, the SYBR Gold method is now used routinely by all members of our group with great consistency and success. PMID:16201894

Huang, Qing; Fu, Wei-Ling

2005-01-01

9

Candida, fluorescent stain (image)  

MedlinePLUS

This microscopic film shows a fluorescent stain of Candida. Candida is a yeast (fungus) that causes mild disease, but in immunocompromised individuals it may cause life-threatening illness. (Image ...

10

Selective fluorescence reaction of indigocarmine stained eosinophil leucocyte granules induced by alkaline reduction of the bound dye to its leuco derivative.  

PubMed

After staining of mammalian blood smears with indigocarmine, eosinophil granules were the unique cell components which stained deeply blue under bright field illumination. Treatment of stained smears with the reducing agent sodium borohydride completely abolished this colour reaction, while under violet-blue exciting light eosinophil granules appeared with bright green fluorescence. Other reducing agents proved less suitable. Spectral analysis of indigocarmine solutions reduced by sodium borohydride showed an emission peak at lambda = 528 nm and confirmed the microscopic observations. These results indicate that the treatment of indigocarmine stained structures with alkaline solutions of strong reducing agents converts the bound dye into its reduced and highly fluorescent leuco derivative. PMID:7518177

Stockert, J C; Trigoso, C I

1994-03-01

11

Exploring the dynamics of fluorescence staining of bacteria with cyanine dyes for the development of kinetic assays  

NASA Astrophysics Data System (ADS)

Bacterial infections continue to be one of the major health risks in the United States. The common occurrence of such infection is one of the major contributors to the high cost of health care and significant patient mortality. The work presented in this thesis describes spectroscopic studies that will contribute to the development of a fluorescent assay that may allow the rapid identification of bacterial species. Herein, the optical interactions between six bacterial species and a series of thiacyanine dyes are investigated. The interactions between the dyes and the bacterial species are hypothesized to be species-specific. For this thesis, two Gram-negative strains, Escherichia coli (E. coli) TOP10 and Enterobacter aerogenes; two Gram-positive bacterial strains, Bacillus sphaericus and Bacillus subtilis; and two Bacillus endospores, B. globigii and B. thuringiensis, were used to test the proposed hypothesis. A series of three thiacyanine dyes---3,3'-diethylthiacyanine iodide (THIA), 3,3'-diethylthiacarbocyanine iodide (THC) and thiazole orange (THO)---were used as fluorescent probes. The basis of our spectroscopic study was to explore the bacterium-induced interactions of the bacterial cells with the individual thiacyanine dyes or with a mixture of the three dyes. Steady-state absorption spectroscopy revealed that the different bacterial species altered the absorption properties of the dyes. Mixed-dye solutions gave unique absorption patterns for each bacteria tested, with competitive binding observed between the bacteria and spectrophotometric probes (thiacyanine dyes). Emission spectroscopy recorded changes in the emission spectra of THIA following the introduction of bacterial cells. Experimental results revealed that the emission enhancement of the dyes resulted from increases in the emission quantum yield of the thiacyanine dyes upon binding to the bacteria cellular components. The recorded emission enhancement data were fitted to an exponential (mono-exponential or bi-exponential) function, and time constants were extracted by regressing on the experimental data. The addition of the TWEEN surfactants decreased the rate at which the dyes interacted with the bacterial cells, which typically resulted in larger time constants derived from an exponential fit. ANOVA analysis of the time constants confirmed that the values of the time constants clustered in a narrow range and were independent of dye concentration and weakly dependent on cell density.

Thomas, Marlon Sheldon

12

Prestaining method as a useful tool for the agarose gel electrophoretic detection of polymerase chain reaction products with a fluorescent dye SYBR gold nucleic acid gel stain.  

PubMed

Three staining methods using SYBR Gold Nucleic Acid Gel Stain (SYBR Gold) as a fluorescent dye were evaluated for the agarose gel electrophoretic detection of DNA. The methods involve prestain, in-gel stain, and poststain methods. DNA markers and polymerase chain reaction (PCR) products obtained by minisatellite variant repeat-PCR (MVR-PCR) amplification in a D1S8 locus were used as model DNA and practical samples, respectively. Among the three methods tested under the usual electrophoretic conditions, a prestain method using a 10000-fold diluted SYBR Gold solution showed most excellent features regarding cost and rapidity to use with good stainability and resolution over loaded DNA amounts of about 98 ng to 300 ng. The prestain method was found to be applicable to the analysis of DNA in MVR-PCR products from a human hair root. PMID:15984194

Suenaga, Emi; Nakamura, Hiroshi

2005-06-01

13

STUDIES ON FLUORESCENT ANTIBODY STAINING  

PubMed Central

1. A study has been made of the non-specific fluorescent staining of splenic imprints treated with fluorescent sheep antibody globulins. 2. In tissue imprints made with the spleens of antigen-stimulated animals, no morphological distinction was evident between areas showing non-specific fluorescence and specific fluorescence. 3. Elimination of non-specific fluorescence was not achieved by any one, or any combination of the following: (a) conjugating only gamma globulins with fluorescein isothiocyanate; (b) removal of dialyzable fluorescent products on sephadex, followed by concentration through the use of pressure dialysis; (c) use of crystalline preparations of fluorescein isothiocyanate. 4. Individual preparations of fluorescent antibodies were separated by gradient elution chromatography on diethylaminoethyl (DEAE) cellulose into fractions possessing different numbers of fluorescein radicals per molecule of globulin. 5. The coupling ratio of 50 mg fluorescein isothiocyanate (FITC) per gm of protein, as commonly advocated, can not be recommended for the precise localization of antibody globulin in tissues owing to the capacity of the coupled products to give non-specific fluorescent staining. When crystalline preparations of FITC are used instead of the amorphous product at 50 mg/gm protein, far too high non-specific fluorescence results. 6. A fraction with bright specific fluorescence and no or negligible nonspecific fluorescence was obtained from each fluorescent antibody that was prepared by using 6 to 8 mg of crystalline fluorescein isothiocyanate per gm of globulin and was then subjected to DEAE-cellulose chromatography and gradient elution to eliminate the most highly coupled molecules.

Goldstein, Gerald; Slizys, Irene S.; Chase, Merrill W.

1961-01-01

14

21 CFR 864.1850 - Dye and chemical solution stains.  

Code of Federal Regulations, 2010 CFR

...Biological Stains § 864.1850 Dye and chemical solution stains. (a) Identification. Dye and chemical solution stains for...purposes are mixtures of synthetic or natural dyes or nondye chemicals in...

2010-04-01

15

21 CFR 864.1850 - Dye and chemical solution stains.  

Code of Federal Regulations, 2010 CFR

...Biological Stains § 864.1850 Dye and chemical solution stains. (a) Identification. Dye and chemical solution stains for...purposes are mixtures of synthetic or natural dyes or nondye chemicals in...

2009-04-01

16

Microencapsulated Fluorescent Dye Penetrant.  

National Technical Information Service (NTIS)

Microencapsulated fluorescent dye pentrant materials were evaluated for feasibility as a technique to detect cracks on metal surfaces when applied as a free flowing dry powder. Various flourescent dye solutions in addition to a commercial penetrant (Zyglo...

S. Allinikov

1979-01-01

17

Fluorescence Changes during Conduction in Nerves Stained with Acridine Orange  

Microsoft Academic Search

Nerves from spider crabs and squid fluoresce when stained with Acridine Orange. The intensity of fluorescence increases during nerve conduction. Prolongation of the electric response in the squid axon is associated with a fluorescence change of similar duration. These findings suggest that the physicochemical properties of the macromolecules around the dye molecules in the nerve membrane drastically change during the

I. Tasaki; L. Carnay; R. Sandlin; A. Watanabe

1969-01-01

18

Optimal Staining and Sample Storage Time for Direct Microscopic Enumeration of Total and Active Bacteria in Soil with Two Fluorescent Dyes  

Microsoft Academic Search

Direct counting techniques,first developed for aquatic samples, can be used to enumerate bacteria in soil and groundwater sediments. Twofluorescent dyes, 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) for actively respiringbacteriaand4*,6-diamidino-2-phenylindole(DAPI)fortotalbacteria,weretestedfortheirusefulness in epifluorescent direct bacterial enumeration in soil. Both dyes can be used for the same soil sample without affecting enumeration results. Staining for 8 h with CTC and for 40 min with DAPI

WEI YU; WALTER K. DODDS; M. KATHERINE BANKS; JEANNIE SKALSKY; ANDERIC A. STRAUSS

1995-01-01

19

Fluorescent dyes specific for quadruplex DNA.  

PubMed Central

Fluorescent dyes which are specific for duplex DNA have found a wide range of applications from staining gels to visualization of chromosomes. Porphyrin dyes have been found which are highly fluorescent in the presence of quadruplex but not duplex DNA. These dyes may offer a route to the specific detection of quadruplex DNA under biologically important conditions. There are three types of DNA quadruplex structures, and these may play important roles in telomere, centromere, triplet repeat, integration sites and other DNAs, and this first set of porphyrin dyes show some selectivity between the quadruplex types.

Arthanari, H; Basu, S; Kawano, T L; Bolton, P H

1998-01-01

20

Nile red: a selective fluorescent stain for intracellular lipid droplets  

Microsoft Academic Search

We report that the dye nile red, 9-diethylamino-5H-benzo(a)phenoxazine-5-one, is an excellent vital stain for the detection of intracellular lipid droplets by fluorescence microscopy and flow cytofluorometry. The specificity of the dye for lipid droplets was assessed on cultured aortic smooth muscle cells and on cultured peritoneal macrophages that were incubated with acetylated low density lipoprotein to induce cytoplasmic lipid overloading.

PHILLIP GREENSPAN; EUGENE P. MAYER; STANLEY D. FOWLER

1985-01-01

21

A fluorescent Gram stain for flow cytometry and epifluorescence microscopy.  

PubMed

The fluorescent nucleic acid binding dyes hexidium iodide (HI) and SYTO 13 were used in combination as a Gram stain for unfixed organisms in suspension. HI penetrated gram-positive but not gram-negative organisms, whereas SYTO 13 penetrated both. When the dyes were used together, gram-negative organisms were rendered green fluorescent by SYTO 13; conversely, gram-positive organisms were rendered red-orange fluorescent by HI, which simultaneously quenched SYTO 13 green fluorescence. The technique correctly predicted the Gram status of 45 strains of clinically relevant organisms, including several known to be gram variable. In addition, representative strains of gram-positive anaerobic organisms, normally decolorized during the traditional Gram stain procedure, were classified correctly by this method. PMID:9647848

Mason, D J; Shanmuganathan, S; Mortimer, F C; Gant, V A

1998-07-01

22

Characterization of SYBR Gold Nucleic Acid Gel Stain: A Dye Optimized for Use with 300-nm Ultraviolet Transilluminators  

Microsoft Academic Search

The highest sensitivity nucleic acid gel stains developed to date are optimally excited using short-wavelength ultraviolet or visible light. This is a disadvantage for laboratories equipped only with 306- or 312-nm UV transilluminators. We have developed a new unsymmetrical cyanine dye that overcomes this problem. This new dye, SYBR Gold nucleic acid gel stain, has two fluorescence excitation maxima when

Rabiya S. Tuma; Matthew P. Beaudet; Xiaokui Jin; Laurie J. Jones; Ching-Ying Cheung; Stephen Yue; Victoria L. Singer

1999-01-01

23

In situ staining with DNA-binding fluorescent dye, Hoechst 33258, to detect microorganisms in the epithelial cells of oral leukoplakia.  

PubMed

This study was performed to investigate the presence of microorganisms in the epithelial cells of leukoplakia. Frozen sections of 20 specimens of leukoplakia were stained with DNA-binding bisbenzimide Hoechst 33258. As a control, 20 specimens of normal oral mucosa and five specimens of normal skin were used. In all preparations of leukoplakia, small granular fluorescing structures were observed within the cytoplasm of the epithelial cells, predominantly within the cytoplasm of prickle cells, although the amount of the granular structures varied between specimens, layers of the epithelium and even areas of the epithelium within a single section. Less granular structures were observed, or none at all, in the cytoplasm of the epithelial cells of normal mucosa. No structures were observed in the cytoplasm of the epithelium of skin. The results in this study strongly suggest that microorganisms are present in the epithelial cells of oral mucosa, and that they are closely associated with the development of oral leukoplakia. It is postulated that the microorganisms in the epithelial cells could be bacteria, particularly mycoplasmas. PMID:11435179

Mizuki, H

2001-09-01

24

Visualization of mitotic chromosomes in filamentous fungi by fluorescence staining and fluorescence in situ hybridization  

Microsoft Academic Search

Mitotic chromosomes of the plant pathogenic filamentous fungi Botrytis cinerea and Alternaria alternata were observed. Chromosomes prepared by the germ tube burst method were stained with the fluorescent dye 4',6-diamidino-2-phenylindole (DAPI) to yield figures with good resolution. Using this method, component chromosomes were clearly distinguished and the chromosome number could be determined. Fluorescence in situ hybridization (FISH) was also successfully

Masatoki Taga; Minoru Murata

1994-01-01

25

Fluorescent dye binding peptides  

US Patent & Trademark Office Database

The present invention is directed to novel polypeptides, termed fluorettes, that bind with high avidity to fluorophore dyes. The peptides find use in a variety of methods and approaches involving fluorophore dyes.

2004-06-08

26

Storable, thermally activated, near-infrared chemiluminescent dyes and dye-stained microparticles for optical imaging  

PubMed Central

Optical molecular imaging employs relatively harmless, low-energy light and technically straightforward instrumentation. Self-illuminating, chemiluminescent systems are especially attractive since they have inherently high signal contrast due to the lack of background emission. Currently, chemiluminescence imaging involves short-lived molecular species that are not stored but instead generated in situ, and they typically emit visible light, which does not penetrate far through heterogeneous biological media. Here, we describe a new paradigm for optical molecular imaging using squaraine rotaxane endoperoxides (SREPs), interlocked fluorescent and chemiluminescent dye molecules that have a squaraine chromophore encapsulated inside a macrocycle endoperoxide. SREPs can be stored indefinitely at temperatures below ?20 °C, but upon warming to body temperature they undergo a unimolecular chemical reaction and emit near infrared light that can pass through a living mouse. Dye-stained microparticles are easily prepared for in vivo near-infrared optical imaging using commercial imaging stations.

Baumes, Jeffrey M.; Gassensmith, Jeremiah J.; Giblin, Jay; Lee, Jung-Jae; White, Alexander G.; Culligan, William J.; Leevy, W. Matthew; Kuno, Masaru; Smith, Bradley D.

2011-01-01

27

Fluorescent redox dyes  

Microsoft Academic Search

The reduction of a new series of tetrazolium salts to red fluorescent formazans by Ehrlich ascites tumor cells is described. The qualitative effect on this reaction of two cell surface-active compounds and of six exogenous electron carriers was investigated by varying the incubation conditions. After incubation of Ehrlich ascites cells with the new colourless, watersoluble 5-cyan-2.3-ditolyltetrazolium salts, bright red water-insoluble

J. Stellmach

1984-01-01

28

Sizing of single fluorescently stained DNA fragments by scanning microscopy  

PubMed Central

We describe an approach to determine DNA fragment sizes based on the fluorescence detection of single adsorbed fragments on specifically coated glass cover slips. The brightness of single fragments stained with the DNA bisintercalation dye TOTO-1 is determined by scanning the surface with a confocal microscope. The brightness of adsorbed fragments is found to be proportional to the fragment length. The method needs only minute amount of DNA, beyond inexpensive and easily available surface coatings, like poly-l-lysine, 3-aminoproyltriethoxysilane and polyornithine, are utilizable. We performed DNA-sizing of fragment lengths between 2 and 14 kb. Further, we resolved the size distribution before and after an enzymatic restriction digest. At this a separation of buffers or enzymes was unnecessary. DNA sizes were determined within an uncertainty of 7–14%. The proposed method is straightforward and can be applied to standardized microtiter plates.

Laib, Stephan; Rankl, Michael; Ruckstuhl, Thomas; Seeger, Stefan

2003-01-01

29

Use of fluorescent staining and flow cytometry for monitoring physiological changes in solventogenic clostridia.  

PubMed

Physiological changes in populations of Clostridium beijerinckii and Clostridium tetanomorphum were monitored by fluorescence staining and flow cytometry. To estimate the number of metabolically active cells in exponential growth, a combination of the dyes propidium iodide and carboxy fluorescein diacetate appeared to be a good choice for both species. During stationary phase, these stains did not reflect physiological changes sufficiently and therefore additional labeling with bis-(1,3-dibutylbarbituric acid) trimethineoxonol was applied. Results of fluorescence staining in solventogenic batch fermentations were compared with substrate-use data, the concentration of key metabolites and growth curves. We demonstrate that measurements by all methods were mutually compatible. PMID:24211310

Patakova, Petra; Linhova, Michaela; Vykydalova, Pavla; Branska, Barbora; Rychtera, Mojmir; Melzoch, Karel

2014-10-01

30

Image analysis of dye stained patterns in soils  

NASA Astrophysics Data System (ADS)

Quality of surface water and groundwater is directly affected by flow processes in the unsaturated zone. In general, it is difficult to measure or model water flow. Indeed, parametrization of hydrological models is problematic and often no unique solution exists. To visualise flow patterns in soils directly dye tracer studies can be done. These experiments provide images of stained soil profiles and their evaluation demands knowledge in hydrology as well as in image analysis and statistics. First, these photographs are converted to binary images classifying the pixels in dye stained and non-stained ones. Then, some feature extraction is necessary to discern relevant hydrological information. In our study we propose to use several index functions to extract different (ideally complementary) features. We associate each image row with a feature vector (i.e. a certain number of image function values) and use these features to cluster the image rows to identify similar image areas. Because images of stained profiles might have different reasonable clusterings, we calculate multiple consensus clusterings. An expert can explore these different solutions and base his/her interpretation of predominant flow mechanisms on quantitative (objective) criteria. The complete workflow from reading-in binary images to final clusterings has been implemented in the free R system, a language and environment for statistical computing. The calculation of image indices is part of our own package Indigo, manipulation of binary images, clustering and visualization of results are done using either build-in facilities in R, additional R packages or the LATEX system.

Bogner, Christina; Trancón y Widemann, Baltasar; Lange, Holger

2013-04-01

31

Specific In Vivo Staining of Astrocytes in the Whole Brain after Intravenous Injection of Sulforhodamine Dyes  

PubMed Central

Fluorescent staining of astrocytes without damaging or interfering with normal brain functions is essential for intravital microscopy studies. Current methods involved either transgenic mice or local intracerebral injection of sulforhodamine 101. Transgenic rat models rarely exist, and in mice, a backcross with GFAP transgenic mice may be difficult. Local injections of fluorescent dyes are invasive. Here, we propose a non-invasive, specific and ubiquitous method to stain astrocytes in vivo. This method is based on iv injection of sulforhodamine dyes and is applicable on rats and mice from postnatal age to adulthood. The astrocytes staining obtained after iv injection was maintained for nearly half a day and showed no adverse reaction on astrocytic calcium signals or electroencephalographic recordings in vivo. The high contrast of the staining facilitates the image processing and allows to quantify 3D morphological parameters of the astrocytes and to characterize their network. Our method may become a reference for in vivo staining of the whole astrocytes population in animal models of neurological disorders.

Appaix, Florence; Girod, Sabine; Boisseau, Sylvie; Romer, Johannes; Vial, Jean-Claude; Albrieux, Mireille; Maurin, Mathieu; Depaulis, Antoine; Guillemain, Isabelle; van der Sanden, Boudewijn

2012-01-01

32

Specific in vivo staining of astrocytes in the whole brain after intravenous injection of sulforhodamine dyes.  

PubMed

Fluorescent staining of astrocytes without damaging or interfering with normal brain functions is essential for intravital microscopy studies. Current methods involved either transgenic mice or local intracerebral injection of sulforhodamine 101. Transgenic rat models rarely exist, and in mice, a backcross with GFAP transgenic mice may be difficult. Local injections of fluorescent dyes are invasive. Here, we propose a non-invasive, specific and ubiquitous method to stain astrocytes in vivo. This method is based on iv injection of sulforhodamine dyes and is applicable on rats and mice from postnatal age to adulthood. The astrocytes staining obtained after iv injection was maintained for nearly half a day and showed no adverse reaction on astrocytic calcium signals or electroencephalographic recordings in vivo. The high contrast of the staining facilitates the image processing and allows to quantify 3D morphological parameters of the astrocytes and to characterize their network. Our method may become a reference for in vivo staining of the whole astrocytes population in animal models of neurological disorders. PMID:22509398

Appaix, Florence; Girod, Sabine; Boisseau, Sylvie; Römer, Johannes; Vial, Jean-Claude; Albrieux, Mireille; Maurin, Mathieu; Depaulis, Antoine; Guillemain, Isabelle; van der Sanden, Boudewijn

2012-01-01

33

Evaluation of optimal DNA staining for triggering by scanning fluorescence microscopy (SFM)  

NASA Astrophysics Data System (ADS)

In imaging and flow cytometry, DNA staining is a common trigger signal for cell identification. Selection of the proper DNA dye is restricted by the hardware configuration of the instrument. The Zeiss Imaging Solutions GmbH (München, Germany) introduced a new automated scanning fluorescence microscope - SFM (Axio Imager.Z1) which combines fluorescence imaging with cytometric parameters measurement. The aim of the study was to select optimal DNA dyes as trigger signal in leukocyte detection and subsequent cytometric analysis of double-labeled leukocytes by SFM. Seven DNA dyes (DAPI, Hoechst 33258, Hoechst 33342, POPO-3, PI, 7-AAD, and TOPRO-3) were tested and found to be suitable for the implemented filtersets (fs) of the SFM (fs: 49, fs: 44, fs: 20). EDTA blood was stained after erythrocyte lysis with DNA dye. Cells were transferred on microscopic slides and embedded in fluorescent mounting medium. Quality of DNA fluorescence signal as well as spillover signals were analyzed by SFM. CD45-APC and CD3-PE as well as CD4-FITC and CD8-APC were selected for immunophenotyping and used in combination with Hoechst. Within the tested DNA dyes DAPI showed relatively low spillover and the best CV value. Due to the low spillover of UV DNA dyes a triple staining of Hoechst and APC and PE (or APC and FITC, respectively) could be analyzed without difficulty. These results were confirmed by FCM measurements. DNA fluorescence is applicable for identifying and triggering leukocytes in SFM analyses. Although some DNA dyes exhibit strong spillover in other fluorescence channels, it was possible to immunophenotype leukocytes. DAPI seems to be best suitable for use in the SFM system and will be used in protocol setups as primary parameter.

Mittag, Anja; Marecka, Monika; Pierzchalski, Arkadiusz; Malkusch, Wolf; Bocsi, József; Tárnok, Attila

2009-02-01

34

Dimeric fluorescent energy transfer dyes comprising asymmetric cyanine azole-indolenine chromophores  

DOEpatents

Novel fluorescent DNA-staining dyes are provided combining asymmetric cyanine azole-indolenine dyes, which provide for strong DNA affinity, large Stokes shifts and emission in the red region of the spectrum. The dyes find particular application in gel electrophoresis and for labels which may be bound to a variety of compositions in a variety of contexts.

Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Albany, CA)

1996-01-01

35

PBXL Fluorescent Dyes for Ultrasensitive Direct Detection  

Microsoft Academic Search

PBXL™ dyes are a group of phycobilisome-based fluors that provide high sensitivity in direct fluorescent detection formats. Phycobilisomes are proteinaceous, supramolecular complexes that are photosynthetic antennae complexes in red algae and cyanobacteria. For the PBXL dyes, the phycobilisome has been chemically cross-linked in such a way that it remains water soluble and stable. Stabilized phycobilisomes (PBXL dyes) have high complex

Steven J. Zoha; Shakuntala Ramnarain; John P. Morseman; Mark W. Moss; F. C. Thomas Allnutt; Yu-Hui Rogers; Bronwen Harvey

1999-01-01

36

Reactive Fluorescent Dyes For Urethane Coatings  

NASA Technical Reports Server (NTRS)

Molecules of fluorescent dyes chemically bound in urethane conformal-coating materials to enable nondestructive detection of flaws in coats through inspection under ultraviolet light, according to proposal. Dye-bonding technique prevents outgassing of dyes, making coating materials suitable for use where flaw-free coats must be assured in instrumentation or other applications in which contamination by outgassing must be minimized.

Willis, Paul B.; Cuddihy, Edward F.

1991-01-01

37

Facile method to stain the bacterial cell surface for super-resolution fluorescence microscopy.  

PubMed

A method to fluorescently stain the surfaces of both Gram-negative and Gram-positive bacterial cells compatible with super-resolution fluorescence microscopy is presented. This method utilizes a commercially-available fluorescent probe to label primary amines at the surface of the cell. We demonstrate efficient staining of two bacterial strains, the Gram-negative Shewanella oneidensis MR-1 and the Gram-positive Bacillus subtilis 168. Using structured illumination microscopy and stochastic optical reconstruction microscopy, which require high quantum yield or specialized dyes, we show that this staining method may be used to resolve the bacterial cell surface with sub-diffraction-limited resolution. We further use this method to identify localization patterns of nanomaterials, specifically cadmium selenide quantum dots, following interaction with bacterial cells. PMID:24816810

Gunsolus, Ian L; Hu, Dehong; Mihai, Cosmin; Lohse, Samuel E; Lee, Chang-Soo; Torelli, Marco D; Hamers, Robert J; Murhpy, Catherine J; Orr, Galya; Haynes, Christy L

2014-06-21

38

Improved Charge-Transfer Fluorescent Dyes  

NASA Technical Reports Server (NTRS)

Improved charge-transfer fluorescent dyes have been developed for use as molecular probes. These dyes are based on benzofuran nuclei with attached phenyl groups substituted with, variously, electron donors, electron acceptors, or combinations of donors and acceptors. Optionally, these dyes could be incorporated as parts of polymer backbones or as pendant groups or attached to certain surfaces via self-assembly-based methods. These dyes exhibit high fluorescence quantum yields -- ranging from 0.2 to 0.98, depending upon solvents and chemical structures. The wavelengths, quantum yields, intensities, and lifetimes of the fluorescence emitted by these dyes vary with (and, hence, can be used as indicators of) the polarities of solvents in which they are dissolved: In solvents of increasing polarity, fluorescence spectra shift to longer wavelengths, fluorescence quantum yields decrease, and fluorescence lifetimes increase. The wavelengths, quantum yields, intensities, and lifetimes are also expected to be sensitive to viscosities and/or glass-transition temperatures. Some chemical species -- especially amines, amino acids, and metal ions -- quench the fluorescence of these dyes, with consequent reductions in intensities, quantum yields, and lifetimes. As a result, the dyes can be used to detect these species. Another useful characteristic of these dyes is a capability for both two-photon and one-photon absorption. Typically, these dyes absorb single photons in the ultraviolet region of the spectrum (wavelengths < 400 nm) and emit photons in the long-wavelength ultraviolet, visible, and, when dissolved in some solvents, near-infrared regions. In addition, these dyes can be excited by two-photon absorption at near-infrared wavelengths (600 to 800 nm) to produce fluorescence spectra identical to those obtained in response to excitation by single photons at half the corresponding wavelengths (300 to 400 nm). While many prior fluorescent dyes exhibit high quantum yields, solvent-polarity- dependent fluorescence behavior, susceptibility to quenching by certain chemical species, and/or two-photon fluorescence, none of them has the combination of all of these attributes. Because the present dyes do have all of these attributes, they have potential utility as molecular probes in a variety of applications. Examples include (1) monitoring curing and deterioration of polymers; (2) monitoring protein expression; (3) high-throughput screening of drugs; (4) monitoring such chemical species as glucose, amines, amino acids, and metal ions; and (5) photodynamic therapy of cancers and other diseases.

Meador, Michael

2005-01-01

39

Assessment of fluorescein-based fluorescent dyes for tracing Neotyphodium endophytes in planta.  

PubMed

Fluorescent dyes were assessed for their ability to stain viable hyphae of the fungi Neotyphodium lolii and N. coenophialum, symbiotic endophytes of the Pooideae grasses Lolium perenne and Festuca arundinacea, respectively. The fluorescein-based fluorophores; fluorescein diacetate (FDA), 5(6)-carboxy-fluorescein diacetate (CFDA), 5-chloromethylfluorescein diacetate (CMFDA) and the chitin-binding stain, Calcofluor while M2R, were assessed for staining of endophyte hyphae in vitro from axenic fungal cultures and in planta, including epidermal leaf sheath peels, nodes, ovaries, embryos and meristems. CMFDA produced the greatest intensity of staining of fungal hyphae and gave excellent contrast in planta compared to the plant cells. Compared to the other dyes, CMFDA was also the least affected by photo bleaching and continued to fluoresce up to 2 h after initial excitation. None of the fluorescent dyes stained fungal hyphae in seed. PMID:22802389

Card, Stuart D; Tapper, Brian A; Lloyd-West, Catherine; Wright, Kathryn M

2013-01-01

40

Fluorescent styryl dyes applied as fast optical probes of cardiac action potential  

Microsoft Academic Search

Several styryl dyes were tested as fast optical probes of membrane action potentials in mammalian heart muscle tissue. After staining, atrial specimens were superfused in physiological salt solution, and fluorescence was excited by an argon ion laser. Excitation spot size on the surface of the preparation was 60 µm in diameter. Dyes RH 160, RH 237, and RH 421 performed

W. Miiller; H. Windisch; H. A. Tritthart

1986-01-01

41

Fluorescence emission spectra of calcofluor stained yeast cell suspensions: heuristic assessment of basis spectra for their linear unmixing.  

PubMed

Fluorescence emission spectra of yeast cell suspensions stained with calcofluor have recently been identified as promising markers of variations in the quality of yeast cell wall. It is shown in this paper how the raw fluorescence spectra of calcofluor can be transformed to reliable spectral signatures of cell wall quality, which are independent of actual dye-to-cell concentrations of examined cell suspensions. Moreover, the presented approach makes it possible to assess basis fluorescence spectra that allows for the spectral unmixing of raw fluorescence spectra in terms of respective fluorescence contributions of calcofluor solvated in the suspension medium and bound to yeast cell walls. PMID:22538834

Plášek, Jaromír; Dostál, Marek; Gášková, Dana

2012-07-01

42

FluoroMyelin(TM) Red is a bright, photostable and non-toxic fluorescent stain for live imaging of myelin  

PubMed Central

FluoroMyelin™ Red is a commercially available water-soluble fluorescent dye that has selectivity for myelin. This dye is marketed for the visualization of myelin in brain cryosections, though it is also used widely to stain myelin in chemically fixed tissue. Here we have investigated the suitability of FluoroMyelin™ Red as a vital stain for live imaging of myelin in myelinating co-cultures of Schwann cells and dorsal root ganglion neurons. We show that addition of FluoroMyelin™ Red to the culture medium results in selective staining of myelin sheaths, with an optimal staining time of 2 hours, and has no apparent adverse effect on the neurons, their axons, or the myelinating cells at the light microscopic level. The fluorescence is bright and photostable, permitting long-term time-lapse imaging. After rinsing the cultures with medium lacking FluoroMyelin™ Red, the dye diffuses out of the myelin with a half life of about 130 minutes resulting in negligible fluorescence remaining after 18–24 hours. In addition, the large Stokes shift exhibited by FluoroMyelin™ Red makes it possible to readily distinguish it from popular and widely used green and red fluorescent probes such as GFP and mCherry. Thus FluoroMyelin™ Red is a useful reagent for live fluorescence imaging studies on myelinated axons.

Monsma, Paula C.; Brown, Anthony

2012-01-01

43

Polymeric fluorescent dyes for labeling of proteins and nucleic acids  

Microsoft Academic Search

In order to increase the sensitivity of fluorescence labeling in biochemical reactions and diagnostic procedures a labeling technique with polymeric fluorescence dyes was established and tested for its applicability. The fluorescence dye is based on the fluorophor coumarine and was covalently linked to the model proteins strepavidine and IgG. The dye was synthesized by radical polymerization of three different types

M. Pitschke; A. Fels; B. Schmidt; L. Heiliger; E. Kuckert; D. Riesner

1995-01-01

44

Fluorescent indicator dyes for calcium ions  

NASA Technical Reports Server (NTRS)

The present invention discloses a new class of highly fluorescent indicator dyes that are specific for calcium ions. The new fluorescent indicator dyes combine a stilbene-type fluorophore with a tetracarboxylate parent Ca.sup.2+ chelating compound having the octacoordinate pattern of liganding groups characteristic of EGTA and BAPTA. Preferred forms contain extra heterocyclic bridges to reinforce the ethylenic bond of the stilbene and to reduce hydrophobicity. Compared to their widely used predecessor, quin2, the new dyes offer up to thirty-fold brighter fluorescence, major changes in wavelength (not just intensity) upon Ca.sup.2+ binding, slightly lower affinities for Ca.sup.2+, slightly longer wavelengths of excitation, and considerably improved selectivity for Ca.sup.2+ over other divalent cations. These properties, particularly the wavelength sensitivity to Ca.sup.2+, make the dyes useful indicators for many intracellular applications, especially in single cells, adherent cell layers, or bulk tissues. The present invention also discloses an improved method for synthesizing alpha-acyloxyalkyl bromides wherein the bromides so synthesized are free of contaminating bis(1-bromoalkyl)ether. The improved method is exemplified herein in the synthesis of acetoxymethyl bromide, a compound useful in preparing the acetoxymethyl esters disclosed herein as novel Ca.sup.2+ specific fluorescent indicators.

Tsien, Roger Y. (Inventor); Grynkiewicz, Grzegorz (Inventor)

1986-01-01

45

Background-free, fast protein staining in sodium dodecyl sulfate polyacrylamide gel using counterion dyes, zincon and ethyl violet.  

PubMed

A background-free, fast protein staining method in polyacrylamide gel electrophoresis using an acidic dye, zincon (ZC) and a basic dye, ethyl violet (EV) is described. It is based on the counterion dye staining technique that employs two oppositely charged dyes to form an ion-pair complex in staining solution. The selective binding of free dye molecules to proteins in acidic solution produces bluish violet-colored bands. It is a rapid and end-point staining procedure, involving only fixing and staining steps that are completed in 1-1.5 h. The detection limit of this method is 8-15 ng of protein that is comparable to the sensitivity of the colloidal Coomassie Brilliant Blue G (CBBG) stain. Due to its sensitivity and speed, this stain may be more practical than any other dye-based stains for routine laboratory purposes. PMID:12481259

Choi, Jung-Kap; Tak, Keong-Hoon; Jin, Li-Tai; Hwang, Sun-Young; Kwon, Tae-Ik; Yoo, Gyurng-Soo

2002-12-01

46

Elastin VII: Aging effects on vascular elastica staining by oil soluble nigrosin dyes  

Microsoft Academic Search

Neutral hydroalcoholic stains with spirit soluble nigrosin (C.I. 50415) and nigrosin base (C.I. 50415B) were applied to a series of human arteries from individuals ranging from newborn to 82 years of age for the demonstration of the selective staining by these dyes of the aging change in their elastica described by Lillie, Pizzolato and Donaldson (1974). The staining is absent

R. D. Lillie; Philip Pizzolato; Jack P. Strong

1976-01-01

47

Storable, thermally activated, near-infrared chemiluminescent dyes and dye-stained microparticles for optical imaging  

NASA Astrophysics Data System (ADS)

Imaging techniques are a vital part of clinical diagnostics, biomedical research and nanotechnology. Optical molecular imaging makes use of relatively harmless, low-energy light and technically straightforward instrumentation. Self-illuminating, chemiluminescent systems are particularly attractive because they have inherently high signal contrast due to the lack of background emission. Currently, chemiluminescence imaging involves short-lived molecular species that are not stored but are instead generated in situ, and they typically emit visible light, which does not penetrate far through heterogeneous biological media. Here, we describe a new paradigm for optical molecular imaging using squaraine rotaxane endoperoxides, interlocked fluorescent and chemiluminescent dye molecules that have a squaraine chromophore encapsulated inside a macrocycle endoperoxide. Squaraine rotaxane endoperoxides can be stored indefinitely at temperatures below -20 °C, but upon warming to body temperature they undergo a unimolecular chemical reaction and emit near-infrared light that can pass through a living mouse.

Baumes, Jeffrey M.; Gassensmith, Jeremiah J.; Giblin, Jay; Lee, Jung-Jae; White, Alexander G.; Culligan, William J.; Leevy, W. Matthew; Kuno, Masaru; Smith, Bradley D.

2010-12-01

48

Improved coomassie blue dye-based fast staining protocol for proteins separated by SDS-PAGE.  

PubMed

The time required to visualize proteins using Coomassie Blue dye has been significantly reduced with the introduction of fast staining protocols based on staining with a Coomassie Blue dye solution at boiling temperatures. However, fast stainings suffer from high gel backgrounds, reducing the signal-to-noise ratio and limiting the number of detectable spots in the case of 2D SDS-PAGE. The aim of this work was to eliminate the high gel background, and thus improve fast staining protocols based on Coomassie Blue dye. We show that merely replacing water with a 4 mM EDTA washing solution at boiling temperatures, results in a transparent gel background within 50 to 60 minutes of destaining. Moreover, when a combination of imidazole-zinc reverse staining and Coomassie Blue-based fast staining is used the sensitivity is improved significantly; nanogram amounts of proteins can be detected using 1D SDS-PAGE, and about 30% to 60% more spots can be detected with 2D SDS-PAGE in plasma, platelet, and rat brain tissue samples. This work represents an optimized fast staining protocol with improved sensitivity, requiring between 60 to 75 minutes to complete protein visualization. PMID:24278455

Májek, Pavel; Riedelová-Reicheltová, Zuzana; Pecánková, Klára; Dyr, Jan E

2013-01-01

49

Improved Coomassie Blue Dye-Based Fast Staining Protocol for Proteins Separated by SDS-PAGE  

PubMed Central

The time required to visualize proteins using Coomassie Blue dye has been significantly reduced with the introduction of fast staining protocols based on staining with a Coomassie Blue dye solution at boiling temperatures. However, fast stainings suffer from high gel backgrounds, reducing the signal-to-noise ratio and limiting the number of detectable spots in the case of 2D SDS-PAGE. The aim of this work was to eliminate the high gel background, and thus improve fast staining protocols based on Coomassie Blue dye. We show that merely replacing water with a 4 mM EDTA washing solution at boiling temperatures, results in a transparent gel background within 50 to 60 minutes of destaining. Moreover, when a combination of imidazole-zinc reverse staining and Coomassie Blue-based fast staining is used the sensitivity is improved significantly; nanogram amounts of proteins can be detected using 1D SDS-PAGE, and about 30% to 60% more spots can be detected with 2D SDS-PAGE in plasma, platelet, and rat brain tissue samples. This work represents an optimized fast staining protocol with improved sensitivity, requiring between 60 to 75 minutes to complete protein visualization.

Majek, Pavel; Riedelova-Reicheltova, Zuzana; Pecankova, Klara; Dyr, Jan E.

2013-01-01

50

Imaging synaptic vesicle recycling by staining and destaining vesicles with FM dyes.  

PubMed

The synaptic vesicle is the essential organelle of the synapse. Many approaches for studying synaptic vesicle recycling have been devised, one of which, the styryl (FM) dye, is well suited for this purpose. FM dyes reversibly stain, but do not permeate, membranes; hence they can specifically label membrane-bound organelles. Their quantum yield is drastically higher when bound to membranes than when in aqueous solution. This protocol describes the imaging of synaptic vesicle recycling by staining and destaining vesicles with FM dyes. Nerve terminals are stimulated (electrically or by depolarization with high K(+)) in the presence of dye, their vesicles are then allowed to recycle, and finally dye is washed from the chamber. In neuromuscular junction (NMJ) preparations, movements of the muscle must be inhibited if imaging during stimulation is desired (e.g., by application of curare, a potent acetylcholine receptor inhibitor). The main characteristics of FM dyes are also reviewed here, as are recent FM dye monitoring techniques that have been used to investigate the kinetics of synaptic vesicle fusion. PMID:22194270

Hoopmann, Peer; Rizzoli, Silvio O; Betz, William J

2012-01-01

51

Use of a fluorescent stain for evaluating in vitro infection with Leishmania panamensis.  

PubMed

Leishmaniasis is a group of endemic diseases produced by infection with Leishmania parasites and affects tropical and subtropical regions of the world. Due to the severe problems related to the treatment of this condition (resistance and toxicity), further studies are needed to evaluate new antileishmanial compounds. The activity of antileishmanial prototypes should be analyzed in models that allow a better interpretation of the findings with respect to natural infection. In this sense, the use of an infection model with macrophages and dendritic cells is a better than using promastigotes alone, in order to establish the potential leishmanicidal activity of a prototype compound. For infection analysis, staining with polychromatic dyes such as Giemsa plus microscopic examination is the gold standard. However, it is common to find problems associated with color uniformity, expertise of the observer, sensitivity and specificity of the technique. For this reason, it's necessary to develop tools and protocols to overcome such limitations. This study assessed the utility of the SYBR® Safe fluorescent dye, considering its affinity for nucleic acids as a useful property for staining the nucleus and kinetoplast of Leishmania parasites within an infected cell. Infection (and subsequent treatment) assays were performed in dendritic cells and macrophages infected with Leishmania panamensis parasites to compare SYBR® Safe and Giemsa stain for the same assay. Correlation coefficients were found to be above 0.9 for both techniques; however, unlike Giemsa, SYBR® Safe staining was easier and provided a clearer observation of internalized parasites. These results support the use of SYBR® Safe as a promising tool for evaluating potential antileishmanials given its advantages over the traditional technique. PMID:21684278

Pérez-Cordero, José-Julián; Sánchez-Suárez, Jeysson; Delgado, Gabriela

2011-09-01

52

Novel 'heavy' dyes for retinal membrane staining during macular surgery: multicenter clinical assessment.  

PubMed

Purpose:? To evaluate the feasibility of two novel 'heavy' dye solutions for staining the internal limiting membrane (ILM) and epiretinal membranes (ERMs), without the need for a prior fluid-air exchange, during macular surgery. Methods:? In this prospective nonrandomized multicenter cohort study, the high molecular weight dyes ILM-Blue™ [0.025% brilliant blue G, 4% polyethylene glycol (PEG)] and MembraneBlue-Dual™ (0.15% trypan blue, 0.025% brilliant blue G, 4% PEG) were randomly used in vitrectomy surgeries for macular disease in 127 eyes of 127 patients. Dye enhanced membrane visualization of the ILM and ERMs, 'ease of membrane peeling', visually detectable perioperative retinal damage, postoperative best-corrected visual acuity (BCVA), dye remnants and other unexpected clinical events were documented by 21 surgeons. Results:? All surgeries were uneventful, and a clear bluish staining, facilitating the identification, delineation and removal of the ILM and ERMs, was reported in all but five cases. None of the surgeries required a fluid-air exchange to assist the dye application. BCVA at 1?month after surgery improved in 83% of the eyes in the MembraneBlue-Dual™ group and in 88% in the ILM-Blue™ group. No dye remnants were detected by ophthalmoscopy, and no retinal adverse effects related to the surgery or use of the dyes were observed. Conclusion:? The 'heavy' dye solutions ILM-Blue™ and MembraneBlue-Dual™ can be injected into a fluid-filled vitreous cavity and may facilitate staining and removal of the ILM and/or ERMs in macular surgery without an additional fluid-air exchange. PMID:23782673

Veckeneer, Marc; Mohr, Andreas; Alharthi, Essam; Azad, Rajvardhan; Bashshur, Ziad F; Bertelli, Enrico; Bejjani, Riad A; Bouassida, Brahim; Bourla, Dan; Crespo, Iñigo Corcóstegui; Fahed, Charbel; Fayyad, Faisal; Mura, Marco; Nawrocki, Jerzy; Rivett, Kelvin; Scharioth, Gabor B; Shkvorchenko, Dmitry O; Szurman, Peter; Van Wijck, Hein; Wong, Ian Y; Wong, David S H; Frank, Johannes; Oellerich, Silke; Bruinsma, Marieke; Melles, Gerrit R J

2014-06-01

53

Evaluation of a fluorescent lectin-based staining technique for some acidophilic mining bacteria  

SciTech Connect

A fluorescence-labeled wheat germ agglutinin staining technique was modified and found to be effective for staining gram-positive, acidophilic mining bacteria. Bacteria identified by others as being gram positive through 16S rRNA sequence analyses, yet clustering near the divergence of that group, stained weakly. Gram-negative bacteria did not stain. Background staining of environmental samples was negligible, and pyrite and soil particles in the samples did not interfere with the staining procedure.

Fife, D.J.; Bruhn, D.F.; Miller, K.S.; Stoner, D.L.

2000-05-01

54

Giemsa as a fluorescent dye for mineralizing bone-like nodules in vitro.  

PubMed

Giemsa was first used as a fluorescent dye for mineralized bone and cartilage in tissue sections. The aim of this study was to establish the use of Giemsa as a fluorescent dye for mineralizing bone-like nodules produced in cell cultures. Osteoblasts were grown under mineralizing conditions for 14 days, producing typical bone-like nodules. Upon staining with Giemsa stock solution for 1 min, the mineralizing nodules could be selectively visualized emitting intense green and red fluorescence when observed under blue and green illumination, respectively. The textural details of the nodules were clearly observed under fluorescence microscopy, allowing to identify regions with different degrees of mineralization. The mineralized nature of the nodules was confirmed using von Kossa's method, Alizarin Red S staining and x-ray mapping for Ca and P in a scanning electron microscope, showing a strong correlation between the mineralizing and the fluorescent nodules. The selective fluorescence was related to the mineral phase, being absent in decalcified samples. The use of Giemsa as a fluorescent dye for mineralizing bone-like nodules presents a simple alternative method to quickly analyze biomineralization assays in vitro under fluorescence microscopy, particularly in the biological evaluation of biomaterials. PMID:22241396

Querido, W; Farina, M; Balduino, A

2012-02-01

55

Synthesis of dye conjugates to visualize the cancer cells using fluorescence microscopy.  

PubMed

The clinical diagnosis of most cancers is based on evaluation of histology microscopic slides to view the size and shape of cellular nuclei and morphological structure of tissue. To achieve this goal for in vivo and in-deep tissues, near infrared dyes-bovine serum albumin and immunoglobulin G conjugates were synthesized. The spectral study shows that the absorption and fluorescence of the dye conjugates are in the "tissue optical window" spectral ranges between 650 and 900 nm. The internalization and pinocytosis of the synthesized compounds were investigated at cell level using fluorescence microscopy to obtain the optimal concentration and staining time. PMID:24787403

Pu, Yang; Tang, Rui; Xue, Jianpeng; Wang, W B; Xu, Baogang; Achilefu, S

2014-04-10

56

Standardization of reagents and methods used in cytological and histological practice with emphasis on dyes, stains and chromogenic reagents  

Microsoft Academic Search

Summary  The need for the standardization of reagents and methods used in the histology laboratory is demonstrated. After definitions of dyes, stains, and chromogenic reagents, existing standards and standards organizations are discussed. This is followed by practical instructions on how to standardize dyes and stains through the preparation of reference materials and the development of chromatographic methods. An overview is presented

H. O. Lyon; A. P. De Leenheer; R. W. Horobin; W. E. Lambert; E. K. W. Schulte; B. Van Liedekerke; D. H. Wittekind

1994-01-01

57

Spectroscopic study and evaluation of red-absorbing fluorescent dyes.  

PubMed

The spectroscopic characteristics (absorption, emission, and fluorescence lifetime) of 13 commercially available red-absorbing fluorescent dyes were studied under a variety of conditions. The dyes included in this study are Alexa647, ATTO655, ATTO680, Bodipy630/650, Cy5, Cy5.5, DiD, DY-630, DY-635, DY-640, DY-650, DY-655, and EVOblue30. The thorough characterization of this class of dyes will facilitate selection of the appropriate red-absorbing fluorescent labels for applications in fluorescence assays. The influences of polarity, viscosity, and the addition of detergent (Tween20) on the spectroscopic properties were investigated, and fluorescence correlation spectroscopy (FCS) was utilized to assess the photophysical properties of the dyes under high excitation conditions. The dyes can be classified into groups based on the results presented. For example, while the fluorescence quantum yield of ATTO655, ATTO680, and EVOblue30 is primarily controlled by the polarity of the surrounding medium, more hydrophobic and structurally flexible dyes of the DY-family are strongly influenced by the viscosity of the medium and the addition of detergents. Covalent binding of the dyes to biotin and subsequent addition of streptavidin results in reversible fluorescence quenching or changes in the relaxation time of other photophysical processes of some dyes, most likely due to interactions with tryptophan residues in the streptavin binding site. PMID:12526709

Buschmann, Volker; Weston, Kenneth D; Sauer, Markus

2003-01-01

58

THERMAL DEPOLARIZATION OF FLUORESCENCE FROM POLYTENE CHROMOSOMES STAINED WITH ACRIDINE ORANGE  

Microsoft Academic Search

The degree of polarization of fluorescence from stretched Chironomus thummi polytcne chromosomes, stained with low concentrations of acridine orange (AO), decreases with increasing temperature. The \\

J. W. MacInnes; ROBERT B. URETZ

1967-01-01

59

Utility of green fluorescent nucleic acid dyes and aluminum oxide membrane filters for rapid epifluorescence enumeration of soil and sediment bacteria.  

PubMed

High background fluorescence and unspecific staining hampered the epifluorescence enumeration of bacteria in 45% of the tested soil and sediment samples with 4',6-diamidino-2-phenylindole (DAPI) and polycarbonate membrane filters. These problems of the determination of total cell counts can be circumvented by using green fluorescent high-affinity nucleic acid dyes and aluminum oxide membrane filters. Due to the bright staining of cells, we recommend SYBR Green II as dye. PMID:9835595

Weinbauer, M G; Beckmann, C; Höfle, M G

1998-12-01

60

Continuous gamma irradiation effects on acrylic staining treated with basic dyes  

NASA Astrophysics Data System (ADS)

Gamma photons were used as a tool to enhance colours producing of the acrylic fibres used in the manufacture of textile in Iraq. Acrylic fibres and basic dyes were irradiated at doses up to 5 Mrad. Different fascinating colours were obtained after the dyeing process. Colours were found to depend on the total dose absorbed. Developed colours are stable against decolorization and their staining are comparable to that of the normal non-irradiated material. Computer Nova 3 fortran was used to differentiate between the obtained colours. Further physical and chemical studies are still under investigation in order to view the nature of changes that took place during radiolysis.

Al-Rawi, Anis M.; Al-Harithy, Rafila S.; Muslih, Raad M.

61

Ultrafast dynamics of epicocconone, a second generation fluorescent protein stain.  

PubMed

Femtosecond upconversion experiment has been carried out for epicocconone and its butylamine adduct in acetonitrile and tert-butanol. An ultrafast component is found to dominate the decay of fluorescence of epicocconone in acetonitrile solution. Upon reacting with butylamine, a model for the epicocconone-protein adduct, this ultrafast component remains almost unaffected but an additional rise time occurs, indicating the formation of a highly emissive species from the locally excited state. This phenomenon is central to the extraordinary applications of epicocconone in biotechnology. The magnitude of the rise time of the butylamine adduct is similar to that of the longer component of the decay of epicocconone in acetonitrile, suggesting that the dynamics of epicocconone and its butylamine adduct are similar. The ultrafast component is slowed upon increasing the viscosity of the solvent. This results in a marked increase in quantum yield and suggests that it corresponds to rapid bond isomerization, leading to a nonradiative decay. Surprisingly, in water/sucrose mixtures, the ultrafast component remains unaffected but there is still an increase in quantum yield, suggesting that there are at least two nonradiative pathways, one involving bond isomerization and another involving proton transfer. The correct interpretation of these data will allow the design of second generation protein stains based on the epicocconone scaffold with increased quantum yields and photostability. PMID:21827198

Chatterjee, Soumit; Burai, Tarak Nath; Karuso, Peter; Datta, Anindya

2011-09-15

62

Homodimeric monomethine cyanine dyes as fluorescent probes of biopolymers  

Microsoft Academic Search

The fluorescence properties of newly synthesized homodimeric monomethine cyanine dyes in the presence of biopolymers are investigated. They do not fluoresce in TE buffer and bidistilled water but become strongly fluorescent (QF=0.3–0.9) in the region 530–650 nm when bound to dsDNA and ssDNA. The detection limit of dsDNA is about 1.7 ng\\/ml. Some of dyes studied are able to distinguish

I Timtcheva; V Maximova; T Deligeorgiev; N Gadjev; K. H Drexhage; I Petkova

2000-01-01

63

Drying of Cryptosporidium oocysts and Giardia cysts to slides abrogates use of vital dyes for viability staining.  

PubMed

Vital dye staining has long been used to assess viability of Cryptosporidium oocysts and Giardia cysts, with staining and enumeration in suspension. Some recent studies, however, have dried samples to microscope slides prior to staining. Here we demonstrate that this approach may considerably underestimate parasite viability in the original sample. PMID:24239946

Robertson, Lucy J; Casaert, Stijn; Valdez-Nava, Yazel; Ehsan, Md Amimul; Claerebout, Edwin

2014-01-01

64

Dimethylformamide interferes with Coomassie dye staining of proteins on blue native gel electrophoresis.  

PubMed

Blue native gel electrophoresis (BN-PAGE) is used extensively for characterization of mitochondrial respiratory complexes and uses the binding of Coomassie brilliant blue G-250 to visualize proteins. Oxidative modification of sulfhydryl groups of such proteins can be evaluated by labeling with iodoacetamide conjugated to biotin (BIAM) and detected with streptavidin peroxidase on Western blots following BN-PAGE. However, dissolving BIAM in dimethylformamide, a recommended solvent, reduces Coomassie blue G staining to proteins during BN-PAGE. This interference is prevented by dissolving BIAM in dimethyl sulfoxide. Precautions in the use of the dye for protein staining subsequent to BIAM labeling are discussed. PMID:24662748

Raghupathy, V; Oommen, Anna; Ramachandran, Anup

2014-06-15

65

[Staining for Helicobacter pylori on gastric mucosa with dye from red cabbage during endoscopy].  

PubMed

Helicobacter pylori has a high urease activity and produces ammonia from urea, resulting in elevation of mucosal pH. Based on this characteristics of H. pylori, we have developed a method for staining H. pylori under endoscopy using dye from red cabbage (San-red RC, San-Ei Chemical Ind., Osaka), a pH indicator, safe for clinical use. After administration of a proton-pump inhibitor and an H2-receptor antagonist, the dye solution, mixed with 2% urea, was sprayed over the mucosa by endoscope. Change in color of the dye was found in some areas infected with H. pylori. The change in color reflects urease activity or amount of ammonia. This method may be useful to find the distribution of H. pylori in the mucosa and to examine the H. pylori-infected mucosa pathophysiologically. PMID:8283630

Kimura, S; Arakawa, T; Kobayashi, K

1993-12-01

66

Fluorescent Treponemal Antibody Absorption Double-Staining Test Evaluation  

PubMed Central

The fluorescent treponemal antibody absorption (FTA-ABS) double-staining (DS) test has been developed for microscopes equipped with incident illumination, and the procedure offers many advantages over the FTA-ABS test when tests are performed with this equipment. In this study, 346 fresh sera, including 35 from patients with syphilis, were evaluated by the FTA-ABS DS test. Parameters for investigation included two readers, each using a different microscope; a new FTA-ABS DS test reporting system; sera heated at 56°C for 30 min versus unheated sera; and sera retested after at least 2 weeks of freezer storage. Agreement for FTA-ABS DS test readings between the two microscopes was 99%. Between-test agreement for the FTA-ABS test with the conventional reporting system and the FTA-ABS DS test with the new reporting system was 95%. Sensitivity calculations based on reactivity for the 35 syphilis sera were 94% for the FTA-ABS DS test and 91% for the FTA-ABS test. Specificity calculations based on non-reactivity of nonsyphilis sera were 98% for the FTA-ABS DS test and 93% for the FTA-ABS test. Differences in percentages appeared to be related to borderline readings in the FTA-ABS test. For example, if the same reporting system was used for the reference FTA-ABS test, the specificity was 97%. When sera were examined within 48 h, no difference was observed in results obtained with heated and unheated sera. Sera frozen for 2 weeks showed comparable results in the FTA-ABS DS test and the FTA-ABS test. These findings strongly support the recommendation that the FTA-ABS DS test be accepted as a confirmatory test for syphilis. The new reporting system for the FTA-ABS DS test would be advantageous for the reference FTA-ABS procedure.

Farshy, Carol E.; Kennedy, Edward J.; Hunter, Elizabeth F.; Larsen, Sandra A.

1983-01-01

67

Fuchsin fluorescence in Mycobacterium tuberculosis: The Ziehl–Neelsen stain in a new light  

Microsoft Academic Search

Tuberculosis (TB) is often diagnosed by observation of reddish pink fuchsin-stained Mycobacterium tuberculosis (MTB) in Ziehl–Neelsen (Z–N) stained smears by transmitted light microscopy. MTB too faintly stained with fuchsin to be seen by transmitted light may be detected by their green-excited orange-red fluorescence; this finding may be clinically relevant.

Howard M. Shapiro; Thomas Hänscheid

2008-01-01

68

Viability assessment of honey bee, Apis mellifera, sperm using dual fluorescent staining  

Microsoft Academic Search

Since the development of instrumental insemination of honey bee (Apis mellifera) queens in the 1930s, there has been interest in the evaluation and in vitro storage of semen. Several fluorescent stains, when used in combination, have been effectively used to assess sperm viability in mammalian and avian species. Our objectives were to test two combinations of living:dead fluorescent stains, SYBR-14

A. M. Collins; A. M. Donoghue

1999-01-01

69

Extrinsic Fluorescent Dyes as Tools for Protein Characterization  

PubMed Central

Noncovalent, extrinsic fluorescent dyes are applied in various fields of protein analysis, e.g. to characterize folding intermediates, measure surface hydrophobicity, and detect aggregation or fibrillation. The main underlying mechanisms, which explain the fluorescence properties of many extrinsic dyes, are solvent relaxation processes and (twisted) intramolecular charge transfer reactions, which are affected by the environment and by interactions of the dyes with proteins. In recent time, the use of extrinsic fluorescent dyes such as ANS, Bis-ANS, Nile Red, Thioflavin T and others has increased, because of their versatility, sensitivity and suitability for high-throughput screening. The intention of this review is to give an overview of available extrinsic dyes, explain their spectral properties, and show illustrative examples of their various applications in protein characterization.

Hawe, Andrea; Sutter, Marc

2008-01-01

70

NIR fluorescent dyes: versatile vehicles for marker and probe applications  

NASA Astrophysics Data System (ADS)

The use of the NIR spectral region (650-900 nm) is advantageous due to the inherently lower background interference and the high molar absorptivities of NIR chromophores. Near-Infrared (NIR) dyes are increasingly used in the biological and medical field. The binding characteristics of NIR dyes to biomolecules are possibly controlled by several factors, including hydrophobicity, size and charge just to mention a few parameters. Binding characteristics of symmetric carbocyanines and found that the hydrophobic nature of the NIR dye is only partially responsible for the binding strength. Upon binding to biomolecules significant fluorescence enhancement can be observed for symmetrical carbocyanines. This fluorescence amplification facilitates the detection of the NIR dye and enhances its utility as NIR reporter. This manuscript discusses some probe and marker applications of such NIR fluorescent dyes. One application discussed here is the use of NIR dyes as markers. For labeling applications the fluorescence intensity of the NIR fluorescent label can significantly be increased by enclosing several dye molecules in nanoparticles. To decrease self quenching dyes that have relatively large Stokes' shift needs to be used. This is achieved by substituting meso position halogens with amino moiety. This substitution can also serve as a linker to covalently attach the dye molecule to the nanoparticle backbone. We report here on the preparation of NIR fluorescent silica nanoparticles. Silica nanoparticles that are modified with aminoreactive moieties can be used as bright fluorescent labels in bioanalytical applications. A new bioanalytical technique to detect and monitor the catalytic activity of the sulfur assimilating enzyme using NIR dyes is reported as well. In this spectroscopic bioanalytical assay a family of Fischer based n-butyl sulfonate substituted dyes that exhibit distinct variation in absorbance and fluorescence properties and strong binding to serum albumin as its sulfonic acid moiety is modified to less water soluble moiety was identified. In polar solvents, these water soluble compounds are strongly fluorescent, however form the less soluble aggregated species with virtual loss of fluorescence when the sulfonate groups are cleaved by enzymatic activity to form the corresponding straight chain alkyl aldehyde derivatives. To achieve this conversion in vitro photo-reduced riboflavin mononucleotide (FMN) with a glucose/ glucose-oxygenase oxygen scavenging system was utilized. The reduced FMN serves as a key substrate in the enzymatic desulfonation. Once the FMNH2 was produced the desulfonation reaction was characterized by using Laser Induced Fluorescence Capillary Zone Electropheresis (LIF-CZE). This method can be utilized as an assay to detect the enzyme activity in vitro with the possibilities of in vivo applications.

Patonay, Gabor; Chapman, Gala; Beckford, Garfield; Henary, Maged

2013-02-01

71

Microassay for proteins on nitrocellulose filter using protein dye-staining procedure.  

PubMed

A simple and rapid microassay for proteins utilizing the protein dye-staining procedure with a nitrocellulose (NC) filter is described. Proteins were directly bound to an NC filter using the "BIO DOT" microfiltration apparatus to ensure their uniformity. The proteins were then stained with a dye (Ponceau Red 3R or amido black 10B), and the optical density of the stained protein spots was directly measured by a densitometer. A good linearity between the optical density and the amount of protein was obtained in the range 0.05 to 10 micrograms. A larger number of samples (up to 96 samples) could be assayed within 1.5 h simultaneously. Contaminating chemicals, such as amino acids, sugars, reducing agents, chelating agents, tris(hydroxymethyl)aminomethane, deoxyribonucleic acid, and nucleotides, did not interfere with the assay. The reproducibility, pH dependency, and application of the assay to the quantitation of a small amount of proteins in body fluids are discussed. PMID:2415018

Nakamura, K; Tanaka, T; Kuwahara, A; Takeo, K

1985-08-01

72

WASTES FROM MANUFACTURE OF DYES AND PIGMENTS. VOLUME 3. STILBENE DYES AND FLUORESCENT BRIGHTENING AGENTS  

EPA Science Inventory

A preliminary study of the manufacture of Stilbene dyes and fluorescent brightening agents was conducted to determine if process waste streams might contain hazardous material. The study first identifies the dyes and pigments that belong to this segment of the industry, the amoun...

73

Improved method to retain cytosolic reporter protein fluorescence while staining for nuclear proteins.  

PubMed

Staining of transcription factors (TFs) together with retention of fluorescent reporter proteins is hindered by loss of fluorescence using current available methods. In this study, it is shown that current TF staining protocols do not destroy fluorescent proteins (FPs) but rather that fixation is not sufficient to retain FPs in the cytosol of the permeabilized cells. In this article, a simple and reliable protocol is elaborated, which allows efficient TF and cytokine staining while retaining FPs inside fixed cells. © 2014 International Society for Advancement of Cytometry. PMID:24616430

Heinen, André P; Wanke, Florian; Moos, Sonja; Attig, Sebastian; Luche, Hervé; Pal, Prajna Paramita; Budisa, Nediljko; Fehling, Hans Jörg; Waisman, Ari; Kurschus, Florian C

2014-07-01

74

Pulsed Dye Laser (577 nm) Treatment of Portwine Stains: Ultrastructural Evidence of Neovascularization and Mast Cell Degranulation in Healed Lesions  

Microsoft Academic Search

Portwine stains were examined before, immediately after, and 1 yr after successful clearance by a pulsed dye laser (577 nm) using ultrastructural techniques. Dilated vascular channels and mast cell hypoplasia characterized lesional skin before treatment. Immediately after treatment, widespread selective vessel necrosis, similar to changes previously described, was observed. One year after laser irradiation, the abnormally ectatic portwine stain vessels

Oon Tian Tan; Diana Whitaker; Jerome M. Garden; George Murphy

1988-01-01

75

Water-Soluble Fluorescing and Laser Dyes.  

National Technical Information Service (NTIS)

This invention relates to water-soluble lasing dyes. When dyes are used in lasers, they are usually dissolved in organic solvents. One widely used solvent is ethanol. As a solvent, water offers advantages over organic compounds in that it is more readily ...

R. A. Henry

1978-01-01

76

A berberine-aniline blue fluorescent staining procedure for suberin, lignin, and callose in plant tissue  

Microsoft Academic Search

Summary A fluorescent staining procedure to detect suberin, lignin and callose in plants has been developed. This procedure greatly improves on previous methods for visualizing Casparian bands in root exodermal and endodermal cells, and performs equally well on a variety of other plant tissues. Berberine was selected as the most suitable replacement forChelidonium majus root extract after comparing the staining

Mark C. Brundrett; Daryl E. Enstone; Carol A. Peterson

1988-01-01

77

Dimeric fluorescent energy transfer dyes comprising asymmetric cyanine azole-indolenine chromophores  

DOEpatents

Novel fluorescent heterodimeric DNA-staining energy transfer dyes are provided combining asymmetric cyanine azole-indolenine dyes, which provide for strong DNA affinity, large Stokes shifts and emission in the red region of the spectrum. The dyes find particular application in gel electrophoresis and for labels which may be bound to a variety of compositions in a variety of contexts. Kits and individual compounds are provided, where the kits find use for simultaneous detection of a variety of moieties, particularly using a single narrow wavelength irradiation source. The individual compounds are characterized by high donor quenching and high affinity to dsDNA as a result of optimizing the length of the linking group separating the two chromophores.

Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Oakland, CA)

1998-01-01

78

Fluorescent staining of ? opioid receptors using naltrexamine derivatives and phycoerythrin  

Microsoft Academic Search

An immunofluorescent technique that is more sensitive than radioligand binding was developed in order to detect opioid receptors expressed on leukocytes. The current study was designed to optimize the method for fluorescently labeling ? opioid receptors. For these experiments, the opioid antagonist naltrexamine was conjugated to either fluorescein (FITC-NTXamine) or biotin (biotin-NTXamine). One-step, two-step, and three-step protocols were compared to

Diane M. P Lawrence; Ian Hutchinson; Ahmad Seyed-Mozaffari; Sydney Archer; Jean M Bidlack

1997-01-01

79

Utility of Green Fluorescent Nucleic Acid Dyes and Aluminum Oxide Membrane Filters for Rapid Epifluorescence Enumeration of Soil and Sediment Bacteria  

Microsoft Academic Search

High background fluorescence and unspecific staining hampered the epifluorescence enumeration of bac- teria in 45% of the tested soil and sediment samples with 4*,6-diamidino-2-phenylindole (DAPI) and polycar- bonate membrane filters. These problems of the determination of total cell counts can be circumvented by using green fluorescent high-affinity nucleic acid dyes and aluminum oxide membrane filters. Due to the bright staining

MARKUS G. WEINBAUER; CHRISTIANE BECKMANN; MANFRED G. HOFLE

1998-01-01

80

Development of Highly Fluorescent Materials Based on Thiophenylimidazole Dyes  

NASA Technical Reports Server (NTRS)

Organic fluorescent materials are expected to find many potential applications in optical devices and photo-functionalized materials. Although many investigations have been focused on heterocyclic compounds such as coumarins, bipyridines, rhodamines, and pyrrole derivatives, little is known for fluorescent imidazole materials. We discovered that one particular class of imidazole derivatives is highly fluorescent. A series of monomeric and polymeric based fluorescent dyes were prepared containing a thiophene unit at the second position of the imidazole ring. Dependence of fluorescence efficiency on parameters such as solvent polarity and substituent groups has been investigated. It was found that a formyl group at the 2-position of the thiophene ring dramatically enhance fluorescence properties. Ion recognition probes indicated their potential as sensor materials. These fluorophores have flexibility for introduction of versatile substituent groups that could improve the fluorescence efficiency and sensor properties.

Santos, Javier; Bu, Xiu R.; Mintz, Eric A.; Meador, Michael A. (Technical Monitor)

2000-01-01

81

Pulsed dye laser-resistant port-wine stains: mechanisms of resistance and implications for treatment.  

PubMed

Port-wine stains (PWS) are among the most common congenital vascular malformations. Unlike capillary haemangiomas, these lesions do not involute spontaneously but rather become progressively more disfiguring as the patient ages. While benign in nature, the cosmetic deformity and attendant psychological and emotional distress prompt the majority of those afflicted to seek treatment. The pulsed dye laser (PDL) has long been considered the treatment of choice for these vascular lesions; however, very few patients achieve total clearance with PDL therapy and a significant number of lesions fail to respond at all. In order to address these recalcitrant cases, the mechanisms that contribute to treatment resistance must be understood and novel laser and light therapies must be employed. This review will address what is currently known about lesion-specific characteristics of PDL-resistant PWS as well as discuss current and future treatment options. PMID:23290045

Savas, J A; Ledon, J A; Franca, K; Chacon, A; Nouri, K

2013-05-01

82

Update on flashlamp pumped pulsed dye laser treatment for port wine stains (capillary malformation) patients  

PubMed Central

Background and Aims: Currently, the method of choice for the treatment of port-wine stains is laser photocoagulation. Because of evolving treatment options, it is no longer enough for port-wine stains merely to be lightened through laser treatment. The best course of management consists of the most appropriate laser that will produce the most complete clearing of a lesion in the fewest treatment sessions with the least morbidity. The goal is generally accomplished with the use of yellow-light lasers. Materials (Subjects) and Methods: Absorption of laser energy by melanin causes localized heating in the epidermis, which may, if not controlled, produce permanent complications such as hypertrophic scarring or dyspigmentation. Refinements of the results can be achieved by using the flashlamp-pumped pulsed dye laser (FLPDL) in conjunction with the cryogen spray cooling (CSC) system. In our related studies, the infrared thermal image instrument is used for doctors in determining the optimum laser light dosage and preventing the side effects caused by FLPDL. Topic application of angiogenesis inhibitor (Imiquimod) in conjunction with pulsed dye laser treatment for the PWS patients has been assessed for improvement of FLPDL treatment. Results: We present the clinical effect of FLPDL, and the efficacy and safety of cooled laser treatment of PWS birthmarks. Our clinical outcome in the laser treatment of patients with PWS has been achieved to maximize thermal impact on targeted vessels, while minimizing adverse complications. Conclusions: CSC in conjunction with FLPDL can improve the treatment of PWS. The infrared image instrument is helpful for doctors in determining the optimum laser light dosage. Topic application of angiogenesis inhibitor (Imiquimod) in conjunction with laser treatment for the PWS patients is promising in the near future.

Hsiao, Yen-Chang; Chang, Cheng-Jen

2011-01-01

83

Image analysis of cells stained by fluorescent in situ hybridization  

SciTech Connect

Specific nucleic acid sequences of about 1 kb can be detected on a routine basis using FISH methods. This is achieved by indirect techniques and conventional microscopy, or with fluorescent probes (direct methods) and integrating detection devices (e.g. CCD cameras). Labeling of probes with defined ratios of two or three fluorophores allows localization of multiple targets, especially when the signals are quantified by image analysis. This requires fluoroescence microscopes equipped with multi band pass filters and computer controlled filter wheels for sequential recording of red, green and blue images using a B/W CCD camera, and correction of occurring image shifts. This combined approach was applied to localize and map genes on chromosomes. In case of nuclei with long extentions of almost linear DNA molecules, (so-called halo preparations), single hybridization sides could be shown.

Tanke, H.J.; Raap, A.K.; Wiegant, J.; Vrolijk, J. (Leiden Univ. (Netherlands))

1993-01-01

84

Red-emitting rhodamine dyes for fluorescence microscopy and nanoscopy.  

PubMed

Fluorescent markers emitting in the red are extremely valuable in biological microscopy since they minimize cellular autofluorescence and increase flexibility in multicolor experiments. Novel rhodamine dyes excitable with 630 nm laser light and emitting at around 660 nm have been developed. The new rhodamines are very photostable and have high fluorescence quantum yields of up to 80 %, long excited state lifetimes of 3.4 ns, and comparatively low intersystem-crossing rates. They perform very well both in conventional and in subdiffraction-resolution microscopy such as STED (stimulated emission depletion) and GSDIM (ground-state depletion with individual molecular return), as well as in single-molecule-based experiments such as fluorescence correlation spectroscopy (FCS). Syntheses of lipophilic and hydrophilic derivatives starting from the same chromophore-containing scaffold are described. Introduction of two sulfo groups provides high solubility in water and a considerable rise in fluorescence quantum yield. The attachment of amino or thiol reactive groups allows the dyes to be used as fluorescent markers in biology. Dyes deuterated at certain positions have narrow and symmetrical molecular mass distribution patterns, and are proposed as new tags in MS or LC-MS for identification and quantification of various substance classes (e.g., amines and thiols) in complex mixtures. High-resolution GSDIM images and live-cell STED-FCS experiments on labeled microtubules and lipids prove the versatility of the novel probes for modern fluorescence microscopy and nanoscopy. PMID:19950338

Kolmakov, Kirill; Belov, Vladimir N; Bierwagen, Jakob; Ringemann, Christian; Müller, Veronika; Eggeling, Christian; Hell, Stefan W

2010-01-01

85

Acridine orange fluorescence techniques as alternatives to traditional Giemsa staining for the diagnosis of malaria in developing countries  

Microsoft Academic Search

Traditional Giemsa-stained thick blood films were compared with 2 fluorescence microscopy techniques, acridine orange (AO) staining of thin blood films and the quantitative buffy coat (QBC™) method, for the microscopical diagnosis of malaria. Of 200 samples examined, 141 were positive by Giemsa staining, 146 by AO and 137 by QBC™. Overall sensitivities for the 2 fluorescence techniques compared to Giemsa

B. S. Lowe; N. K. Jeffa; L. New; C. Pedersen; K. Engbaek; K. Marsh

1996-01-01

86

Approximate analytic solutions for the optical pumping of fluorescent dyes  

NASA Technical Reports Server (NTRS)

A general technique for solving a system of rate equations describing the interaction of an electromagnetic field and a molecular system is presented. The method is used to obtain approximate time-dependent solutions for the upper-level population of fluorescent dyes in the presence of a pump field.

Lawandy, N. M.

1978-01-01

87

Approximate analytic solutions for the optical pumping of fluorescent dyes  

NASA Technical Reports Server (NTRS)

A general technique for solving a system of rate equations describing the interaction of an electromagnetic field and a molecular system is presented. The method is used to obtain approximate time-dependent solutions for the upper-level populations of fluorescent dyes in the presence of a pump field.

Lawandy, N. M.

1979-01-01

88

Tailor-Made Dyes for Fluorescence Correlation Spectroscopy (FCS)  

Microsoft Academic Search

Two new fluorescent labels are presented that are op- timized for excitation with He\\/Ne laser and red diode lasers. Application in FCS and labeling of proteins and oligomers are demonstrated. A strong rise of quantum yield and emission life time upon binding to biomolecules are characteristic features of the dyes.

Peter Czerney; Frank Lehmann; Matthias Wenzel; Volker Buschmann; Anja Dietrich; Gerhard J. Mohr

2001-01-01

89

Phosphoprotein staining for sodium dodecyl sulfate-polyacrylamide gel electrophoresis using fluorescent reagent morin hydrate.  

PubMed

A fluorescence-based stain with 3,5,7,2',4'-pentahydroxyflavone (morin hydrate, MH) was designed to stain phosphoproteins in one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Al(3+) was applied as a "fixed bridge," providing an efficient energy transfer channel between phosphoprotein and MH, to produce a strong fluorescent complex for the determination of phosphoprotein. As little as 62.5ng of ?-casein (7 or 8 phosphates) and ?-casein (5 phosphates), 125ng of ovalbumin (2 phosphates), and ?-casein (1 phosphate) could be visualized with a wide linear dynamic range. In comparison with conventional methods, MH stain is a time-saving method that takes just 90min. It also has good compatibility with routine protein stainings such as Coomassie Brilliant Blue R (CBBR) and SYPRO Ruby for total protein analysis. PMID:23274386

Wang, Xu; Hwang, Sun-Young; Cong, Wei-Tao; Jin, Li-Tai; Choi, Jung-Kap

2013-04-01

90

Bacterial ring rot testing with the indirect fluorescent antibody staining procedure  

Microsoft Academic Search

The indirect fluorescent antibody staining (IFAS) procedure was successfully used in place of the Gram stain procedure to\\u000a confirm diagnosis of bacterial ring rot. Antisera produced against untreatedCorynebacterium sepedonicum cells, glutaraldehyde-fixed cells, heat-treated glutaraldehydefixed cells, and a cell extract had useful IFAS titers and\\u000a similar specificity. Optimum antiserum dilution was critical for a reliable test; at high antiserum dilution optimum

S. H. De Boer; R. J. Copeman

1980-01-01

91

Neoplasm diagnostics based on fluorescence of polymethine dyes  

NASA Astrophysics Data System (ADS)

Investigated polymethine dye TICS has near IR bands of fluorescence and absorption within the transparency region of biological tissues. It can be detected up to 1.5 cm from the surface of the skin. The intensity of a fluorescence signal of TICS is linear for doses up to 2 mg/kg in both tumor and muscle tissue. The ratio of an intensity of light induced fluorescence in tumor tissue to one in muscle tissue is up to 3.6 for rapidly growing tumors. The retention time of TICS is 7 days in all tissues. TICS can be used in the detection of tumor boundaries and tumor internal structure.

Samtsov, Michael P.; Voropay, Eugene S.; Chalov, Vadim N.; Zhavrid, Edvard A.

2002-05-01

92

Inhibition of beta-amyloid aggregation by fluorescent dye labels  

NASA Astrophysics Data System (ADS)

The fluorescence decay of beta-amyloid's (A?) intrinsic fluorophore tyrosine has been used for sensing the oligomer formation of dye-labelled A? monomers and the results compared with previously studied oligomerization of the non-labelled A? peptides. It has been demonstrated that two different sized, covalently bound probes 7-diethylaminocoumarin-3-carbonyl and Hilyte Fluor 488 (HLF), alter the rate and character of oligomerization to different extents. The ability of HLF to inhibit formation of highly ordered structures containing beta-sheets was also shown. The implications of our findings for using fluorescence methods in amyloidosis research are discussed and the advantages of this auto-fluorescence approach highlighted.

Amaro, Mariana; Wellbrock, Thorben; Birch, David J. S.; Rolinski, Olaf J.

2014-02-01

93

Efficacy of flashlamp-pumped pulsed dye laser therapy for port wine stains: clinical assessment and histopathological characteristics  

Microsoft Academic Search

Clinicopathological evaluation of flashlamp-pumped dye laser therapy for port wine stains was conducted on 474 subjects (135 male and 339 female) ranging in age from less than a year to 85 years (median = 17; lower quartile = 7 and upper quartile = 28). There was a significant variation in the rate of favourable response among lesion sites but the

Keiko Onizuka; Katsumi Tsuneda; Yoshisada Shibata; Masahiro Ito; Ichiro Sekine

1995-01-01

94

Fluorescence of Alexa Fluor Dye Tracks Protein Folding  

PubMed Central

Fluorescence spectroscopy is an important tool for the characterization of protein folding. Often, a protein is labeled with appropriate fluorescent donor and acceptor probes and folding-induced changes in Förster Resonance Energy Transfer (FRET) are monitored. However, conformational changes of the protein potentially affect fluorescence properties of both probes, thereby profoundly complicating interpretation of FRET data. In this study, we assess the effects protein folding has on fluorescence properties of Alexa Fluor 488 (A488), which is commonly used as FRET donor. Here, A488 is covalently attached to Cys69 of apoflavodoxin from Azotobacter vinelandii. Although coupling of A488 slightly destabilizes apoflavodoxin, the three-state folding of this protein, which involves a molten globule intermediate, is unaffected. Upon folding of apoflavodoxin, fluorescence emission intensity of A488 changes significantly. To illuminate the molecular sources of this alteration, we applied steady state and time-resolved fluorescence techniques. The results obtained show that tryptophans cause folding-induced changes in quenching of Alexa dye. Compared to unfolded protein, static quenching of A488 is increased in the molten globule. Upon populating the native state both static and dynamic quenching of A488 decrease considerably. We show that fluorescence quenching of Alexa Fluor dyes is a sensitive reporter of conformational changes during protein folding.

Lindhoud, Simon; Westphal, Adrie H.; Visser, Antonie J. W. G.; Borst, Jan Willem; van Mierlo, Carlo P. M.

2012-01-01

95

Sensitive Immunofluorescent Staining of Cells via Generation of Fluorescent Nanoscale Polymer Films in Response to Biorecognition  

PubMed Central

Immunofluorescent staining is central to nearly all cell-based research, yet only a few fluorescent signal amplification approaches for cell staining exist, each with distinct limitations. Here, the authors present a novel, fluorescent polymerization-based amplification (FPBA) method that is shown to enable similar signal intensities as the highly sensitive, enzyme-based tyramide signal amplification (TSA) approach. Being non-enzymatic, FPBA is not expected to suffer from nonspecific staining of endogenous enzymes, as occurs with enzyme-based approaches. FPBA employs probes labeled with photopolymerization initiators, which lead to the controlled formation of fluorescent polymer films only at targeted biorecognition sites. Nuclear pore complex proteins (NPCs; in membranes), vimentin (in filaments), and von Willebrand factor (in granules) were all successfully immunostained by FPBA. Also, FPBA was demonstrated to be capable of multicolor immunostaining of multiple antigens. To assess relative sensitivity, decreasing concentrations of anti-NPC antibody were used, indicating that both FPBA and TSA stained NPC down to a 1:100,000 dilution. Nonspecific, cytoplasmic signal resulting from NPC staining was found to be reduced up to 5.5-fold in FPBA as compared to TSA, demonstrating better signal localization with FPBA. FPBA’s unique approach affords a combination of preferred attributes, including high sensitivity and specificity not otherwise available with current techniques.

Avens, Heather J.; Berron, Brad J.; May, Allison M.; Voigt, Katerina R.; Seedorf, Gregory J.; Balasubramaniam, Vivek; Bowman, Christopher N.

2011-01-01

96

CCD microscopy and image analysis of cells and chromosomes stained by fluorescence in situ hybridization  

Microsoft Academic Search

Summary  This paper reviews methods and applications of CCD microscopy for analysing cells and chromosomes subjected to fluorescence in situ hybridization (FISH). The current status of indirect and direct FISH staining methods with respect to probe labelling, detection sensitivity, multiplicity and DNA resolution is summarized. Microscope hardware, including special multi-band pass filters and CCD cameras required for FISH analysis, is described.

H. J. Tanke; R. J. Florijn; J. Wiegant; A. K. Raap; J. Vrolijk

1995-01-01

97

Fluorescent labeling of dendritic spines in cell cultures with the carbocyanine dye "DiI"  

PubMed Central

Analyzing cell morphology is a key component to understand neuronal function. Several staining techniques have been developed to facilitate the morphological analysis of neurons, including the use of fluorescent markers, such as DiI (1,1?-dioctadecyl-3,3,3?,3?-tetramethylindocarbocyanine perchlorate). DiI is a carbocyanine membrane dye that exhibits enhanced fluorescence upon insertion of its lipophilic hydrocarbon chains into the lipid membrane of cells. The high photostability and prominent fluorescence of the dye serves as an effective means of illuminating cellular architecture in individual neurons, including detailed dendritic arborizations and spines in cell culture and tissue sections. Here, we specifically optimized a simple and reliable method to fluorescently label and visualize dissociated hippocampal neurons using DiI and high-resolution confocal microscopic imaging. With high efficacy, this method accurately labels neuronal and synaptic morphology to permit quantitative analysis of dendritic spines. Accurate imaging techniques of these fine neuronal specializations are vital to the study of their morphology and can help delineate structure-function relationships in the central nervous system.

Cheng, Connie; Trzcinski, Olivia; Doering, Laurie C.

2014-01-01

98

Influence of selected fluorescent dyes on small aquatic organisms  

NASA Astrophysics Data System (ADS)

Rhodamine B and Rhodamine WT are fluorescent dyes commonly used as tracers in hydrological investigations. Since introducing intensely red substances into rivers raises understandable doubts of ecological nature, the authors aimed at examining the influence of these dyes on small water fauna using bioindication methods. Quantitative results, calculated with the use of Bliss-Weber probit statistical method, were achieved by means of standardized ecotoxicological tests containing ready-to-hatch resting forms of fairy shrimp ( Thamnocephalus platyurus). Qualitative studies included observation of water flea crustacean ( Daphnia magna) and horned planorbis snail ( Planorbis corneus), both typically present in rivers and representative for temperate climate, as well as guppy fish ( Poecilla reticulata), paramecium protozoan ( Paramaecium caudatum) and the above-mentioned fairy shrimp. The investigation revealed that both dyes in concentrations used for hydrological purposes are low enough to exert almost no toxic impact on water fauna considered.

Rowi?ski, Pawe? M.; Chrzanowski, Marcin M.

2011-02-01

99

Geminate recombination as a photoprotection mechanism for fluorescent dyes.  

PubMed

Despite common presumption due to fast photodestruction pathways through higher excited states, we show that further improvement of photostability is still achievable with diffusion-limited photoprotection formulas. Single-molecule fluorescence spectroscopy reveals that thiolate ions effectively quench triplet states of dyes by photoinduced electron transfer. Interestingly, this reaction rarely yields a radical anion of the dye, but direct return to the ground state is promoted by an almost instantaneous back electron transfer (geminate recombination). This type of mechanism is not detected for commonly used reductants such as ascorbic acid and trolox. The mechanism avoids the formation of radical cations and improves the photostability of single fluorophores. We find that a combination of ?-mercaptoethanol and classical reducing and oxidizing systems yields the best results for several dyes including Atto532 and Alexa568. PMID:24715383

Holzmeister, Phil; Gietl, Andreas; Tinnefeld, Philip

2014-05-26

100

The assessment of port wine stains in children following multiple pulsed-dye laser treatments.  

PubMed

The purpose of this study was to compare 3 methods of assessment of pediatric port wine stains (PWSs) following multiple pulsed-dye laser (PDL) treatments; (i) parental evaluation, (ii) objective evaluation utilizing L*a*b* color measurement, and (iii) the visual inspection of serial photographs by blinded observers. Twenty-one children who had received at least 4 prior PDL treatments were prospectively enrolled. Following additional PDL treatment, 72.5% of the parental responses indicated a lighter PWS; 85% said that they would continue with further treatment. According to the assessments by 3 observers, only 33.3% to 61.9% (correlation coefficients: 0.41 and 0.54; P < 0.01) of the PDL treatments resulted in a perceived lightening. L*a*b* measurements were not significantly correlated with the observers' perceptions. L*a*b* assessment is not a clinically useful method to evaluate PDL response in the PWS previously treated. Relying solely on parental assessment may lead to overtreatment without a demonstrable benefit. PMID:18362573

Naran, Sanjay; Gilmore, John; Deleyiannis, Frederic W-B

2008-04-01

101

Assessment of gamete quality for the eastern oyster (Crassostrea virginica) by use of fluorescent dyes  

USGS Publications Warehouse

Evaluation of sperm motility is the single most widely used parameter to determine semen quality in mammals and aquatic species. While a good indicator for fresh sperm viability, post-thaw motility is not always effective at predicting fertilizing ability. Techniques using fluorescent dyes can assess functionality of mammalian sperm, but have not been widely applied in aquatic organisms. The eastern oyster Crassostrea virginica is an important mollusk in the United States, and cryopreservation protocols have been developed to preserve sperm and larvae to assist research and hatchery production. In this study, protocols were developed to assess sperm cell membrane integrity and mitochondrial function by flow cytometry and to assess viability of eggs by fluorescence microscopy. The fluorescent dyes SYBR 14 and propidium iodide (PI) (to assess membrane integrity) and rhodamine 123 (R123) (to assess mitochondrial membrane potential) were used to evaluate the quality of thawed oyster sperm previously cryopreserved with different cryoprotectant and thawing treatments. Membrane integrity results were correlated with motility of thawed sperm and mitochondrial membrane potential with fertilizing ability. Fluorescein diacetate (FDA) was used to assess cytotoxicity of cryoprotectant solutions and post-thaw damage to oyster eggs. The results indicated that membrane integrity (P = 0.004) and thawing treatments (P = 0.04), and mitochondrial membrane potential (P = 0.0015) were correlated with motility. Fertilizing ability was correlated with cryoprotectant treatments (P = 0.0258) and with mitochondrial membrane potential (P = 0.001). The dye FDA was useful in indicating structural integrity of fresh and thawed eggs. Exposure of eggs, without freezing, to dimethyl sulfoxide yielded higher percentages of stained eggs and fertilization rate than did exposure to propylene glycol (P = 0.002). Thawed eggs were not stained with FDA (<1%) and larvae were not produced. ?? 2006 Elsevier Inc. All rights reserved.

Paniagua-Chavez, C. G.; Jenkins, J.; Segovia, M.; Tiersch, T. R.

2006-01-01

102

Modulated photophysics of a cationic DNA-staining dye inside protein bovine serum albumin: study of binding interaction and structural changes of protein.  

PubMed

The binding affinity of cationic DNA-staining dye, propidium iodide, with transport protein, bovine serum albumin, has been explored using UV-vis absorption, fluorescence, and circular dichroism spectroscopy. Steady state and time resolved fluorescence studies authenticate that fluorescence quenching of bovine serum albumin by propidium iodide is due to bovine serum albumin-propidium iodide complex formation. Thermodynamic parameters obtained from temperature dependent spectral studies cast light on binding interaction between the probe and protein. Site marker competitive binding has been encountered using phenylbutazone and flufenamic acid for site I and site II, respectively. Energy transfer efficiency and distance between bovine serum albumin and propidium iodide have been determined using Förster mechanism. Structural stabilization or destabilization of protein by propidium iodide has been investigated by urea denaturation study. The circular dichroism study as well as FT-IR measurement demonstrates some configurational changes of the protein in presence of the dye. Docking studies support the experimental data thereby reinforcing the binding site of the probe to the subdomain IIA of bovine serum albumin. PMID:24216153

Samanta, Anuva; Jana, Sankar; Ray, Debarati; Guchhait, Nikhil

2014-03-01

103

A novel method for monitoring tumor proliferation in vivo using fluorescent dye DiD.  

PubMed

Monitoring single cell proliferation in vivo is difficult, but optimizing this technique is essential in order to expand our knowledge of the regulation of tumor proliferation. In this study, we used a lipophilic fluorescent dye, DiD, that rapidly and stably integrates into the phospholipid cell membrane. We cultured DiD-stained prostate cancer cell lines for 10 days and isolated cells by flow cytometry based on expression levels of DiD. We found that a decrease in DiD intensity was correlated to the reduction of EdU, where the DiD-high population proliferated more slowly than the DiD-low population and the DiD-low population exhibited a higher mitotic index. We also found that DiD was detected after 3 weeks of implantation in an in vivo setting. Importantly, DiD dye did not have any effect on normal cell growth, whereas a gold standard fluorescent dye for measuring cell proliferation, CFSE, slowed cell proliferation. Although further study is indicated, DiD can be useful for identifying the molecular mechanisms underlying tumor proliferation in vivo. © 2014 International Society for Advancement of Cytometry. PMID:24700602

Yumoto, Kenji; Berry, Janice E; Taichman, Russell S; Shiozawa, Yusuke

2014-06-01

104

Effects of a nanoscale silica matrix on the fluorescence quantum yield of encapsulated dye molecules.  

PubMed

The effects that nanometer-sized matrices have on the properties of molecules encapsulated within the nanomatrix are not fully understood. In this work, dye-doped silica nanoparticles were employed as a model for studying the effects of a nanomatrix on the fluorescence quantum yield of encapsulated dye molecules. Two types of dye molecules were selected based on their different responses to the surrounding media. Several factors that affect fluorescence quantum yields were investigated, including aggregation of dye molecules, diffusion of atmospheric oxygen, concentration of dye molecules, and size of the nanomatrix. The results showed that the silica nanomatrix has a varied effect on the fluorescence quantum yield of encapsulated dye molecules, including enhancement, quenching and insignificant changes. Both the properties of dye molecules and the conditions of the nanomatrix played important roles in these effects. Finally, a physical model was proposed to explain the varied nanomatrix effects on the fluorescence quantum yield of encapsulated dye molecules. PMID:23958712

Liang, Song; Shephard, Kali; Pierce, David T; Zhao, Julia Xiaojun

2013-10-01

105

Treatment of Port-Wine Stains with Flash Lamp Pumped Pulsed Dye Laser on Indian Skin: A Six Year Study  

PubMed Central

Context: Port-wine stain (PWS) is one of the commonly encountered congenital cutaneous vascular lesions, with an equal sex distribution. Pulsed dye lasers (PDL) have revolutionized the treatment of both congential and acquired cutaneous vascular lesions. The pulsed dye lasers owing to its superior efficacy and safety profile have become the gold standard for the management of port-wine stains. Aims: To evaluate the efficacy and side effects of pulsed dye laser for the management of Port-wine stain on Indian skin. Materials and Methods: Seventy five patients of Fitzpatrick skin types IV&V with PWS underwent multiple treatments with PDL (V beam-Candela) over a period of six years at monthly intervals. Laser parameters were wavelength 595nm, spot sizes 7-10mm, fluence 6-12 j/cm2, pulse duration 0.45-10ms, along with cryogen cooling. Serial photographs were taken before and after every session. Clinical improvement scores of comparable photographs using a quartile grading (o=<20%, 1=21-40%, 2=41-60%, 3=61-80%, 4=>80%) were judged independently by two dermatologists after the series of treatment. Minimum number of treatments was 6 and maximum 17. They were followed up at six monthly intervals to observe re darkening of PWS. Results: No patient showed total clearance.Grade3 improvement was observed in 70 % of children and 50% of adults after 8-10 sessions. Children showed better and faster response than adults. Thirty percent of patients developed post inflammatory hyper pigmentation which resolved over a period of six to eight weeks. Two patients had superficial scarring due to stacking of pulses. None of the patients showed re darkening of PWS till now. Conclusion: Pulsed dye laser is an effective and safe treatment for port-wine stain in Indian skin.

Thajudheen, Chandroth Ponnambath; Jyothy, Kannangath; Priyadarshini, Arul

2014-01-01

106

Synthetic routes to fluorescent dyes exhibiting large Stokes shifts.  

PubMed

Derivatives of isomeric 2-(hydroxytolyl)-4,6-dimethylamino-1,3,5-triazines have been synthesized in high yields in a controlled manner using a multistep reaction sequence. Iodination of either 2-(1'-hydroxy-6'-methylphen-2'-yl)- or 2-(1'-hydroxy-4'-methylphen-2'-yl)-4,6-dimethylamino-1,3,5-triazine with ICl provides species differing in the positioning of the iodo group relative to the hydroxyl which readily undergo Suzuki, Sonogashira, and Heck reactions under Pd(0) catalysis. Thus, thienyl, bisthienyl, and 3,4-ethylenedioxythienyl groups have been directly grafted, while unsubstituted polycyclic aromatics such as pyrene and perylene have been linked via alkyne bridges, as have ethynyldifluoroborondipyrromethane (BODIPY) dyes prepared in situ. The presence of a hydrogen bond in the ground state involving the hydroxyl substituent has been established by proton NMR and several X-ray structure determinations. All of the new dyes with a simple substituent (phenyl, thienyl) exhibited a pronounced green fluorescence resulting from an intramolecular proton transfer in the excited state (ESIPT) which produces a large Stokes shift (>10,000 cm(-1)). With other dyes, the fluorescence of the keto form responsible for the ESIPT process could be used as the input energy in efficient intramolecular energy transfer processes. Replacing perylene with pyrene allowed reversal of the direction of energy transfer from the polyaromatic module to the keto form. PMID:22834858

Rihn, Sandra; Retailleau, Pascal; De Nicola, Antoinette; Ulrich, Gilles; Ziessel, Raymond

2012-10-19

107

A pitfall in using BODIPY dyes to label lipid droplets for fluorescence microscopy  

Microsoft Academic Search

The lipid droplet (LD) has become a focus of intense research. Fluorescence labeling is indispensable for the cell biological\\u000a analysis of the LD, and a lipophilic fluorescence dye, BODIPY 493\\/503, which emits bright green fluorescence has been used\\u000a extensively for LD labeling. The dye is convenient for double fluorescence labeling, but we noticed that it emits red fluorescence\\u000a under certain

Yuki Ohsaki; Yuki Shinohara; Michitaka Suzuki; Toyoshi Fujimoto

2010-01-01

108

A new chromosome fluorescence banding technique combining DAPI staining with image analysis in plants  

Microsoft Academic Search

In this study, a new chromosome fluorescence banding technique was developed in plants. The technique combined 4?,6-diamidino-2-phenylindole (DAPI) staining with software analysis including three-dimensional imaging after deconvolution. Clear multiple and adjacent DAPI bands like G-bands were obtained by this technique in the tested species including Hordeum vulgare L., Oryza officinalis, Wall & Watt, Triticum aestivum L., Lilium brownii, Brown, and

Jing Yu Liu; Chao Wen She; Zhong Li Hu; Zhi Yong Xiong; Li Hua Liu; Yun Chun Song

2004-01-01

109

Synthesis and properties of phosphonic acid containing cyanine and squaraine dyes for use as fluorescent labels.  

PubMed

Cyanine and squaraine dyes that contain one or two phosphonate groups attached directly to the aromatic residues of the dyes were synthesized. Absorption and fluorescence properties of the dyes were determined. Succinimidyl active esters were prepared from the dyes and were used to label proteins and oligonucleotides. Some of the dyes permit the preparation of brighter conjugates than do commercially available analogues such as Cy3 and Cy5. PMID:17927261

Reddington, Mark V

2007-01-01

110

[Monitoring of photodynamic therapy of port wine stain by fluorescence spectroscopy].  

PubMed

The blood drug level and the formation of photoproduct were monitored during photodynamic therapy (PDT) of port wine stain (PWS) by fluorescence spectroscopy. The irradiation was implemented by a 532 nm double-frequency Nd:YAG laser, and the collection of fluorescence spectra was completed with the use of spectrograph and ICCD. In the experiment for validation of the system, the fluorescence basis spectra of hematoporphyrin monomethyl ether (HMME)-sensitized mouse normal skin were constructed, and, by least-square fitting, HMME fluorescence (624 nm) could be discriminated from that of photoproduct (652 nm). The fitting of fluorescence spectra measured from PWS patients skin containing PSD-007 was performed with the same basis spectra as those from the mouse skin. The curves of blood drug level of different patients with significant variance, as well as those of formation and bleaching of photoproduct were obtained. Fluorescence spectroscopy monitoring system and fitting method presented here can provide technical means for rigorous quantitative PDT dosimetry method, and the results obtained here will make for the individual scheme of PDT. PMID:18051530

Wang, Lei; Gu, Ying; Li, Xiao-Song; Liu, Fan-Guang; Yu, Chang-Qing

2007-09-01

111

Interaction of fluorescent dyes with DNA and spermine using fluorescence spectroscopy.  

PubMed

Oligonucleotides labelled with fluorescent dyes are widely used as probes for the identification of DNA sequences in detection methods using optical spectroscopies such as fluorescence and surface enhanced Raman scattering (SERS). Spermine is widely used in surface enhanced based assays as a charge reduction and aggregating agent as it interacts strongly with the phosphate backbone and has shown to enhance the signal of a labelled oligonucleotide. The fluorescence intensity of two commonly used labels, FAM and TAMRA, were compared when spermine was added under different experimental conditions. There was a marked difference upon conjugating the free dye to an oligonucleotide, when FAM was conjugated to an oligonucleotide there was around a six fold decrease in emission, compared to a six fold increase when TAMRA was conjugated to an oligonucleotide. Dye labelled single and double stranded DNA also behaved differently with double stranded DNA labelled with FAM being a much more efficient emitter in the mid pH range, however TAMRA becomes increasingly less efficient as the pH rises. Upon addition of the base spermine, signal enhancement from the FAM labelled oligonucleotide is observed. Increasing probe concentrations of TAMRA oligonucleotide above 0.5 ?M led to signal reduction most likely through quenching, either by an interaction with guanine, or through self-quenching. By using different bases for comparison, spermine and triethylamine (TEA), different affects were observed in the measured fluorescence signals. When TEA was added to FAM, a reduction in the pH dependence of fluorescence was observed, which may be useful for mid pH range assays. With the drive to increase information content and decrease time and complexity of DNA assays it is likely that more assays will be carried out in complex media such as extracted DNA fragments and PCR product. This model study indicates that dye DNA and dye spermine interactions are dye specific and that extreme care with conditions is necessary particularly if it is intended to determine the concentrations of multiple analytes using probes labelled with different dyes. PMID:24915043

Gracie, K; Smith, W E; Yip, P; Sutter, J U; Birch, D J S; Graham, D; Faulds, K

2014-06-30

112

Organic fluorescent thermometers based on borylated arylisoquinoline dyes.  

PubMed

Borylated arylisoquinolines with redshifted internal charge-transfer (ICT) emission were prepared and characterized. Upon heating, significant fluorescence quenching was observed, which forms the basis for a molecular thermometer. In the investigated temperature range (283-323?K) an average sensitivity of -1.2 to -1.8?%?K(-1) was found for the variations in fluorescence quantum yield and lifetime. In the physiological temperature window (298-318?K) the average sensitivity even reaches values of up to -2.4?%?K(-1) . The thermometer function is interpreted as the interplay between excited ICT states of different geometry. In addition, the formation of an intramolecular Lewis pair can be followed by (11) B?NMR spectroscopy. This provides a handle to monitor temperature-dependent ground-state geometry changes of the dyes. The role of steric hindrance is addressed by the inclusion of a derivative that lacks the Lewis pair formation. PMID:24861774

Pais, Vânia F; Lassaletta, José M; Fernández, Rosario; El-Sheshtawy, Hamdy S; Ros, Abel; Pischel, Uwe

2014-06-16

113

Discrimination of live and early apoptotic mononuclear cells by the fluorescent SYTO 16 vital dye.  

PubMed

Accurate detection of apoptotic cells is important for the determination of cell viability. The aim of this study was to compare the sensitivity of the cell permeant SYTO 16 fluorescent dye for detecting early apoptotic mononuclear cells (MNCs) in normal donor blood with other apoptosis assays [i.e. Annexin-V, light scatter/7-amino-actinomycin-D (7-AAD) and chloromethyl-X-rosamine (CMXRos)] and to identify critical parameters for optimal SYTO 16 staining. Apoptosis was induced in normal human leukocytes from adult peripheral blood or cord blood, or the Jurkat T-lymphocytic cell line and assessed by fluorescence microscopy and flow cytometry. Dual labelling showed that SYTO 16 detected more apoptotic MNCs compared to Annexin-V. SYTO 16 staining intensity was consistent with the light scatter profiles expected of live, apoptotic and necrotic MNCs and was more objective than light scatter/7-AAD. CMXRos staining required considerable care and may not be a robust marker of apoptotic primary MNCs. For SYTO 16 flow cytometric analysis, the optimal conditions for staining 1x10(6) leukocytes were 4 nM SYTO 16 in the presence of 30 muM verapamil for 25-45 min at 37 degrees C in media containing calcium/magnesium supplemented with protein. A P-glycoprotein inhibitor, such as verapamil, and calcium/magnesium are essential for optimal loading of SYTO 16 into live MNCs and discrimination of apoptotic MNCs in normal blood samples. SYTO 16 is a sensitive, simple, inexpensive 'live cell' method for the discrimination of live, apoptotic and necrotic normal blood MNCs and is more sensitive for detecting apoptosis in these cells than Annexin-V or light scatter/7-AAD. PMID:16165150

Sparrow, Rosemary L; Tippett, Emma

2005-10-30

114

The Mode of Cell Wall Growth in Selected Archaea Is Similar to the General Mode of Cell Wall Growth in Bacteria as Revealed by Fluorescent Dye Analysis ? †  

PubMed Central

The surfaces of 8 bacterial and 23 archaeal species, including many hyperthermophilic Archaea, could be stained using succinimidyl esters of fluorescent dyes. This allowed us for the first time to analyze the mode of cell wall growth in Archaea by subculturing stained cells. The data obtained show that incorporation of new cell wall material in Archaea follows the pattern observed for Bacteria: in the coccoid species Pyrococcus furiosus incorporation was in the region of septum formation while for the rod-shaped species Methanopyrus kandleri and Methanothermus sociabilis, a diffuse incorporation of cell wall material over the cell length was observed. Cell surface appendages like fimbriae/pili, fibers, or flagella were detectable by fluorescence staining only in a very few cases although their presence was proven by electron microscopy. Our data in addition prove that Alexa Fluor dyes can be used for in situ analyses at temperatures up to 100°C.

Wirth, Reinhard; Bellack, Annett; Bertl, Markus; Bilek, Yvonne; Heimerl, Thomas; Herzog, Bastian; Leisner, Madeleine; Probst, Alexander; Rachel, Reinhard; Sarbu, Christina; Schopf, Simone; Wanner, Gerhard

2011-01-01

115

pH-Sensitive Fluorescent Dyes: Are They Really pH-Sensitive in Cells?  

PubMed Central

Chemically synthesized near-infrared (NIR) aza-BODIPY dyes displayed OFF/ON fluorescence at acidic pH (pKa = 6.2-6.6) through the suppression of photoinduced electron transfer (PET) and/or internal charge transfer (ICT) process. The apparent pKas of the dyes were shifted well above physiological pH in hydrophobic microenvironment, which led to “turned-on” fluorescence in micelles and liposomes at neutral and basic pH. Bovine serum albumin (BSA) also activated the fluorescence, though to a much less extent. When these small molecular dyes entered cells, instead of being fluorescent only in acidic organelles, the whole cytoplasm exhibited fluorescence, with signal/background ratio as high as ?10 in no-wash live cell imaging. The dye 1 labeled cells remained highly fluorescent even after 3 days. Moreover, slight variations of the dye structure resulted in significantly different intracellular fluorescence behaviors, possibly due to their different cellular uptake and intracellular activation capabilities. After separation of cellular components, the fraction of plasma membrane and endoplasmic reticulum (ER) showed the highest fluorescence, further confirming the fluorescence activation by membrane structures. The fluorescence intensity of these dyes at different intracellular pH (6.80 and 8.00) did not differ significantly, indicating that intracellular pH did not play a critical role. Altogether, we showed here for the first time that the fluorescence of pH-sensitive aza-BODIPY dyes were switched intracellularly not by acidic pH, but by intracellular membranes (and proteins as well). The excellent membrane permeability, ultra high fluorescence contrast ratio, persistent fluorescent signal, and minimum biological interference of dye 1 make it an ideal choice for live cell imaging and in vivo cell tracking. These findings also imply that the intracellular fluorescent properties of pH-sensitive dyes should be carefully examined before used as pH indicators.

Zhang, Xiao-Xiang; Wang, Zhe; Yue, Xuyi; Ma, Ying; Kiesewetter, Dale O.; Chen, Xiaoyuan

2013-01-01

116

Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique  

Microsoft Academic Search

This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as

O. Abdel-Kareem; A. Eltokhy; M. A. Harith

2011-01-01

117

Acetylcholine-synthesizing amacrine cells: identification and selective staining by using radioautography and fluorescent markers.  

PubMed

The fluorescent DNA stain 4,6,diamidino-2-phenylindole (DAPI) was applied to the cut axons of the rabbit optic tract, from which it was retrogradely transported to the retinal ganglion cell bodies. The labelled retinas were isolated from the eye and maintained in vitro in the presence of [3H]choline. They were then quick-frozen, freeze-dried, vacuum-embedded, and radioautographed on dry emulsion for identification of the acetylcholine-synthesizing cells. Inspection of the radioautographs by fluorescence microscopy showed the two labels not to co-exist: the cells that contained the transported fluorescence did not contain radioactive acetylcholine. In other animals the optic nerve was sectioned, causing retrograde degeneration of a large fraction of the ganglion cells. A population of small, round neurons in the ganglion cell layer was spared. These retinas synthesized [3H]acetylcholine at the same rate as control tissues; and radioautography showed an identical distribution of the acetylcholine-synthesizing cells. We conclude that the acetylcholine-synthesizing neurons of the ganglion cell layer are displaced amacrine cells. When DAPI was injected intraocularly instead of being applied to the optic tract, a regular mosaic of neurons in the ganglion cell layer was selectively stained, and two bands of fluorescence were observed in the inner plexiform layer, at the level where two bands of radioactive acetylcholine were observed in radioautographs. Quantitative analysis showed that the DAPI-stained cells were the same size as those that survive optic nerve section. Like the acetylcholine-synthesizing cells, they appear to be displaced amacrines; when wheatgerm agglutinin labelled by Evans blue was applied to the optic tract and DAPI was injected intraocularly, the red fluorescence of Evans blue and the blue fluorescence of DAPI accumulated in different cells. When DAPI was injected intraocularly and radioautography for acetylcholine was carried out, the cells brightly labelled by DAPI were found to have synthesized acetylcholine. We conclude that topically applied DAPI selectively labels the acetylcholine-synthesizing neurons of the ganglion cell layer. The distribution of the acetylcholine-synthesizing cells was established by counting the DAPI-labelled cells in whole-mounts.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6083567

Masland, R H; Mills, J W; Hayden, S A

1984-11-22

118

Synthesis, characterization and fluorescence studies of novel tetrachloroperylene-azo hybrid dyes.  

PubMed

Novel rylene-azo hybrid dyes have been synthesized by condensation of azo-dyes with tetrachloroperylene dianhydride, possessing stupendous thermal, chemical and photochemical stability. Phenolic azo dyes are used for the nucleophilic replacement of chlorine substituents at 1,6,7,12-positions of perylene 3,4,9,10-dianhydride system. The absorption maxima (?max) of these dyes have been determined in diverse solvents such as water, ethanol, methanol, ethyl acetate and N, N-dimethylformamide. Fluorescence spectra are taken in water and highest fluorescence was exhibited by dyes containing carboxylic groups. The ?max and fluorescence of these dyes is greatly affected by polarity of solvents. The structures of newly synthesized rylene-azo hybrid dyes have been confirmed by UV, FTIR and (1)HNMR spectroscopy. PMID:24912451

Saeed, Aamer; Shabir, Ghulam

2014-07-01

119

In vivo imaging using polymeric nanoparticles stained with near-infrared chemiluminescent and fluorescent squaraine catenane endoperoxide†  

PubMed Central

Polystyrene nanoparticles stained with squaraine catenane endoperoxide exhibit remarkably high chemiluminescence and enable optical imaging of biodistribution in living mice. Whole-body chemiluminescence imaging was much more effective than fluorescence at identifying lung accumulation of the nanoparticles.

Lee, Jung-Jae; White, Alexander G.; Rice, Douglas R.; Smith, Bradley D.

2013-01-01

120

Measuring Fluorescent Dye in the Bubbly and Sediment-Laden Surfzone.  

PubMed

Decisions about recreational beach closures would be enhanced if better estimates of surfzone contaminant transport and dilution were available. In situ methods for measuring fluorescent Rhodamine WT dye tracer in the surfzone are presented, increasing the temporal and spatial resolution over previous surfzone techniques. Bubbles and sand suspended by breaking waves in the surfzone interfere with in situ optical fluorometer dye measurements, increasing the lower bound for dye detection ( approximately 1 ppb) and reducing (quenching) measured dye concentrations. Simultaneous turbidity measurements are used to estimate the level of bubble and sand interference and correct dye estimates. After correction, root-mean-square dye concentration errors are estimated to be < 5% of dye concentration magnitude, thus demonstrating the viability of in situ surfzone fluorescent dye measurements. The surfzone techniques developed here may be applicable to other environments with high bubble and sand concentrations (e.g., cascading rivers and streams). PMID:19898671

Clark, David B; Feddersen, Falk; Omand, Melissa M; Guza, R T

2009-11-01

121

Femtosecond fluorescence dynamics and molecular interactions in a water-soluble nonlinear optical polymeric dye  

Microsoft Academic Search

The excited state dynamics of a water-soluble polymeric dye poly(S-119) was investigated using femtosecond time-resolved fluorescence upconversion. Multi-exponential relaxation of fluorescence was observed for poly(S-119) in picosecond and sub-picosecond time ranges. The azo-chromophore of the functionalized polymeric dye Sunset Yellow was used as a model compound for detailed investigations of intermolecular interactions. Excited state decay of this azo-dye can be

O. Varnavski; T Goodson

2000-01-01

122

Multispot live-image autofocusing for high-throughput microscopy of fluorescently stained bacteria.  

PubMed

Screening by automated high-throughput microscopy has become a valuable research tool. An essential component of such systems is the autonomous acquisition of focused images. Here we describe the implementation of a high-precision autofocus routine for imaging of fluorescently stained bacteria on a commercially available microscope. We integrated various concepts and strategies that together substantially enhance the performance of autonomous image acquisition. These are (i) nested focusing in bright-field and fluorescence illumination, (ii) autofocusing by continuous life-image acquisition during movement in z-direction rather than at distinct z-positions, (iii) assessment of the quality and topology of a field of view (FOV) by multispot focus measurements, and (iv) acquisition of z-stacks and application of an extended depth of field algorithm to compensate for FOV unevenness. The freely provided program and documented source code allow ready adaptation of the here presented approach to various platforms and scientific questions. PMID:19658173

Zeder, M; Pernthaler, J

2009-09-01

123

Pyrophosphate selective fluorescent chemosensors: cascade recognition of nuclear stain mimicking DAPI.  

PubMed

A new zinc(ii) complex with a condensed hydroxynaphthyl pyridine (SPHN) as the coordinated ligand has been synthesized for the selective recognition of pyrophosphate (PPi) over other anions including phosphate in a mixed aqueous solution. The fluorescence enhancement of SPHN in association with Zn(2+) ions is quenched in the presence of intracellular pyrophosphate. This phenomenon is utilized in the construction of a logic gate. The binding of SPHN with Zn(2+) and its displacement by PPi have been established by photophysical investigation and supported by the DFT level of studies. The development of blue fluorescence in the {} complex upon binding of zinc with is shown to be useful as a nucleus marker in a cell similar to the commercially available staining compound, DAPI (diamino-2-phenylindole). PMID:25010909

Goswami, Shyamaprosad; Das, Avijit Kumar; Pakhira, Bholanath; Basu Roy, Sohini; Maity, Anup Kumar; Saha, Partha; Sarkar, Sabyasachi

2014-07-29

124

Design and synthesis of polymer-functionalized NIR fluorescent dyes--magnetic nanoparticles for bioimaging.  

PubMed

The fluorescent probes having complete spectral separation between absorption and emission spectra (large Stokes shift) are highly useful for solar concentrators and bioimaging. In bioimaging application, NIR fluorescent dyes have a greater advantage in tissue penetration depth compared to visible-emitting organic dyes or inorganic quantum dots. Here we report the design, synthesis, and characterization of an amphiphilic polymer, poly(isobutylene-alt-maleic anhyride)-functionalized near-infrared (NIR) IR-820 dye and its conjugates with iron oxide (Fe3O4) magnetic nanoparticles (MNPs) for optical and magnetic resonance (MR) imaging. Our results demonstrate that the Stokes shift of unmodified dye can be tuned (from ~106 to 208 nm) by the functionalization of the dye with polymer and MNPs. The fabrication of bimodal probes involves (i) the synthesis of NIR fluorescent dye (IR-820 cyanine) functionalized with ethylenediamine linker in high yield, >90%, (ii) polymer conjugation to the functionalized NIR fluorescent dye, and (iii) grafting the polymer-conjugated dyes on iron oxide MNPs. The resulting uniform, small-sized (ca. 6 nm) NIR fluorescent dye-magnetic hybrid nanoparticles (NPs) exhibit a wider emissive range (800-1000 nm) and minimal cytotoxicity. Our preliminary studies demonstrate the potential utility of these NPs in bioimaging by means of direct labeling of cancerous HeLa cells via NIR fluorescence microscopy and good negative contrast enhancement in T2-weighted MR imaging of a murine model. PMID:23869722

Yen, Swee Kuan; Ja?czewski, Dominik; Lakshmi, Jeeva Lavanya; Dolmanan, Surani Bin; Tripathy, Sudhiranjan; Ho, Vincent H B; Vijayaragavan, Vimalan; Hariharan, Anushya; Padmanabhan, Parasuraman; Bhakoo, Kishore K; Sudhaharan, Thankiah; Ahmed, Sohail; Zhang, Yong; Tamil Selvan, Subramanian

2013-08-27

125

Staining diatoms with rhodamine dyes: control of emission colour in photonic biocomposites  

PubMed Central

The incorporation of rhodamine dyes in the cell wall of diatoms Coscinodiscus granii and Coscinodiscus wailesii for the production of luminescent hybrid nanostructures is investigated. By systematic variation of the substitution pattern of the rhodamine core, we found that carbonic acids are considerably better suited than esters because of their physiological compatibility. The amino substitution pattern that controls the optical properties of the chromophore has no critical influence on dye uptake and incorporation, thus a variety of biocomposites with different emission maxima can be prepared. Applications in biomineralization studies as well as in materials science are envisioned.

Kucki, Melanie; Fuhrmann-Lieker, Thomas

2012-01-01

126

Confocal microscopy of multiple-stained biological specimens using fluorescence lifetimes  

NASA Astrophysics Data System (ADS)

We here report on using fluorescence life times recordings in confocal microscopy to detect individual fluorophores in multiple stained tissue. Using indirect fluorescence immunohistochemistry with secondary antisera conjugated to the fluorophores Lissamine Rhodamine (LRSC), Texas Red or Cyanine 3.18 (Cy-3); one, two or three epitopes were labelled in tissues from rat spinal cord and dorsal root ganglia. The tissue sections were examined and analyzed in a beam-scanning confocal microscope equipped with devices for fluorescence lifetime measurements. The results show that fluorophore life-times can be used to separate two or more fluorophores in individual axon terminals, provided that the fluorophore labelling is strong enough and the life-times of the deployed compounds are sufficiently separate. Thus, the presence of Cy-3, LRSC and Texas Red, as well as mixtures of these compounds could be detected in individual tissue profiles. Contribution by tissue autofluorescence was unmistakably identified by its complex multiexponential emission decay. We also show that fluorescence lifetimes differs between antiserum-conjugates for one and the same fluorophore, and the possibility to use fluorophore life-times to probe chemical environmental changes in situ is discussed. The implementation of a life-time recording device in a confocal microscope has the advantage of providing a good spatial resolution. Furthermore, by deploying fluorophores emitting within the same wavelength band, problems due to chromatic errors will be completely avoided.

Brismar, Hjalmar; Ulfhake, Brun

1995-03-01

127

A new probe using hybrid virus-dye nanoparticles for near-infrared fluorescence tomography  

NASA Astrophysics Data System (ADS)

A fluorescent probe based on bionanoparticle cowpea mosaic virus has been developed for near-infrared fluorescence tomography. A unique advantage of this probe is that over 30 dye molecules can be loaded onto each viral nanoparticle with an average diameter of 30 nm, making high local dye concentration (˜1.8 mM) possible without significant fluorescence quenching. This ability of high loading of local dye concentration would increase the signal-to-noise ratio considerably, thus sensitivity for detection. We demonstrate successful tomographic fluorescence imaging of a target containing the virus-dye nanoparticles embedded in a tissue-like phantom. Tomographic fluorescence data were obtained through a multi-channel frequency-domain system and the spatial maps of fluorescence quantum yield were recovered with a finite-element-based reconstruction algorithm.

Wu, Changfeng; Barnhill, Hannah; Liang, Xiaoping; Wang, Qian; Jiang, Huabei

2005-11-01

128

Short communication Inhibition of multidrug resistance transporters in the diatom Thalassiosira rotula facilitates dye staining  

Microsoft Academic Search

Cells are protected by multidrug resistance transporters, which remove potentially harmful chemicals entering the cells from the environment or originating endogenously from the cellular metabolism. Multidrug resistance transporters have not been investigated so far in marine eukary- otic algae like diatoms. We investigated the uptake of a calcium-sensitive dye, Fura 2 acetoxymethylester (AM), by the marine diatom Thalas- siosira rotula

Cordula Scherer; Karen Wiltshire; Ulf Bickmeyer

129

Sublimation enthalpy of dye molecules measured using fluorescence  

NASA Astrophysics Data System (ADS)

We present an in-flight fluorescence detection scheme for molecular beams which is applied to determine the enthalpy of sublimation of dye molecules. We investigate tetraphenylporphyrin (TPP), porphine, and nile red, which are believed to be suitable candidates for molecular de Broglie wave interferometry [L. Hackermüller et al., Phys. Rev. Lett. 91, 090408, 2003]. The measured values are Hsub(TPP)=142+/-3 kJ/mol, Hsub(porphine)=87+/-3 kJ/mol, and Hsub(nile red)=66+/-2 kJ/mol. For TPP, sublimation enthalpies differ in the literature by more than a factor of 2. Our measurements confirm a value at the lower end of this scale. We discuss changes in the character of the molecular flow with the source temperature as a prime reason for discrepancies in the published data.

Stefanov, André; Stibor, Alexander; Dominguez-Clarimon, Alex; Arndt, Markus

2004-10-01

130

Hollow mesoporous silica nanoparticles for intracellular delivery of fluorescent dye  

PubMed Central

In this study, hollow mesoporous silica nanoparticles (HMSNs) were synthesized using the sol-gel/emulsion approach and its potential application in drug delivery was assessed. The HMSNs were characterized, by transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM), nitrogen adsorption/desorption and Brunauer-Emmett-Teller (BET), to have a mesoporous layer on its surface, with an average pore diameter of about 2 nm and a surface area of 880 m2/g. Fluorescein isothiocyanate (FITC) loaded into these HMSNs was used as a model platform to assess its efficacy as a drug delivery tool. Its release kinetic study revealed a sequential release of FITC from the HMSNs for over a period of one week when soaked in inorganic solution, while a burst release kinetic of the dye was observed just within a few hours of soaking in organic solution. These FITC-loaded HMSNs was also found capable to be internalized by live human cervical cancer cells (HeLa), wherein it was quickly released into the cytoplasm within a short period of time after intracellular uptake. We envision that these HMSNs, with large pores and high efficacy to adsorb chemicals such as the fluorescent dye FITC, could serve as a delivery vehicle for controlled release of chemicals administered into live cells, opening potential to a diverse range of applications including drug storage and release as well as metabolic manipulation of cells.

2011-01-01

131

Use of SYTO 13, a fluorescent dye binding nucleic acids, for the detection of microparticles in in vitro systems  

PubMed Central

Microparticles (MPs) are small membrane-bound vesicles that are released from activated or dying cells by a blebbing process. These particles contain nuclear and cytoplasmic components and represent unique biomarkers for disease. The small size of particles, however, limits detection using flow cytometry with either light scatter or staining for surface markers. Because MPs contain DNA and RNA, we have explored the use of SYTO 13, a member of the class of SYTO dyes, for particle detection. SYTO 13 is cell permeable and has a high fluorescent yield when bound to DNA or RNA. In this study, we compared detection of MPs using either light scatter or SYTO 13 staining, testing the hypothesis that, with fluorescence detection with SYTO 13, problems of “noise” with light scatter are reduced and the range of MP sizes detected is increased. In these experiments, particles were obtained from lymphoid cell lines treated in vitro to undergo apoptosis. As these results showed, STYO 13 allowed the detection of 1.5 to 2.9 times as many particles as did light scatter. The increased sensitivity was observed with 3 different cell lines and was independent of inducing stimulus. Treatment of fixed and permeabilized MPs with DNase and RNase showed that SYTO 13 binding resulted from interaction with both DNA and RNA. Together, these findings indicate that the nucleic acid content of MPs provides the basis for their detection in in vitro systems and suggests the utility of fluorescent dyes like SYTO 13 for more sensitive quantitative assays.

Ullal, Anirudh J.; Pisetsky, David S.; Reich, Charles F.

2010-01-01

132

Use of SYTO 13, a fluorescent dye binding nucleic acids, for the detection of microparticles in in vitro systems.  

PubMed

Microparticles (MPs) are small membrane-bound vesicles that are released from activated or dying cells by a blebbing process. These particles contain nuclear and cytoplasmic components and represent unique biomarkers for disease. The small size of particles, however, limits detection using flow cytometry with either light scatter or staining for surface markers. Because MPs contain DNA and RNA, we have explored the use of SYTO 13, a member of the class of SYTO dyes, for particle detection. SYTO 13 is cell permeable and has a high fluorescent yield when bound to DNA or RNA. In this study, we compared detection of MPs using either light scatter or SYTO 13 staining, testing the hypothesis that, with fluorescence detection with SYTO 13, problems of "noise" with light scatter are reduced and the range of MP sizes detected is increased. In these experiments, particles were obtained from lymphoid cell lines treated in vitro to undergo apoptosis. As these results showed, STYO 13 allowed the detection of 1.5-2.9 times as many particles as did light scatter. The increased sensitivity was observed with three different cell lines and was independent of inducing stimulus. Treatment of fixed and permeabilized MPs with DNase and RNase showed that SYTO 13 binding resulted from interaction with both DNA and RNA. Together, these findings indicate that the nucleic acid content of MPs provides the basis for their detection in in vitro systems and suggests the utility of fluorescent dyes like SYTO 13 for more sensitive quantitative assays. PMID:20104574

Ullal, Anirudh J; Pisetsky, David S; Reich, Charles F

2010-03-01

133

Synthesis and characterization of fluorescent dyes-magnetic nanoparticles for bioimaging applications  

NASA Astrophysics Data System (ADS)

Magnetic-fluorescent nanoparticles have been emerging as potential bimodal probes in the area of bioimaging. However, near-infrared (NIR) fluorescent dye as a fluorescent material for bimodal probe remains unexplored. The tailor-design of NIR cyanine dye is challenging. Herein, we report the synthesis and characterization of novel functional IR 820 dye. This modified IR 820 has been successfully conjugated with long and short back-bone chain polymers. All these compounds preserve good water solubility and photochemical properties. The magnetic-fluorescent bimodal probe has been demonstrated, wherein the magnetic nanoparticles have been coated with dye-polymer. The cytotoxicity studies on HeLa cells show that MNP@dye-polymer with short back-bone chain has better cell viability.

Yen, Swee Kuan; Ja?czewski, Dominik; Bin Dolmanan, Surani; Sudhiranjan, Tripathy; Selvan, Subramanian T.

2012-02-01

134

Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique  

NASA Astrophysics Data System (ADS)

This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

Abdel-Kareem, O.; Eltokhy, A.; Harith, M. A.

2011-09-01

135

Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique  

SciTech Connect

This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

Abdel-Kareem, O. [Conservation Department, Faculty of Archaeology, Cairo University (Egypt); Eltokhy, A.; Harith, M. A. [National Institute of Laser Enhanced Science, Cairo University (Egypt)

2011-09-22

136

Actin assessment in addition to specific immuno-fluorescence staining to demonstrate rickettsial growth in cell culture.  

PubMed

Rickettsiae are able to spread within infected cell mono-layers by modifying intra-cellular actin formations. The study analyzes whether a visualization of actin modifications in addition to specific immuno-fluorescence staining of rickettsiae might facilitate the proof of rickettsial growth in cell culture. Cell mono-layers of Vero E6 und BGM cells were infected with Rickettsia honei. Intra-cellular actin was fluorescence stained with TRITC-(tetra-methyl-5,6-isothiocyanate)-labeled phalloidin in addition to specific immuno-fluorescence staining of rickettsiae with FITC-(fluorescein-isothiocyanate)-labeled antibodies. DNA of bacteria and cells was counter-stained with DAPI (4´,6-diamino-2-phenyl-indole). Cell cultures infected with Vaccinia virus were used as positive controls, cell cultures infected with Coxiella burnetii as negative controls. High concentrations of R. honei are necessary to demonstrate characteristic modifications of the intra-cellular actin. This effect is more pronounced in Vero E6 cells than in BGM cells. Actin staining with phalloidin is not suited for an early proof of rickettsial growth in cell culture but may confirm unclear findings in specific immuno-fluorescence staining in case of sufficient bacterial density. PMID:24265939

Frickmann, Hagen; Schröpfer, Elmar; Dobler, Gerhard

2013-09-01

137

Functional molecular lumino-materials to probe serum albumins: solid phase selective staining through noncovalent fluorescent labeling.  

PubMed

Selective staining of human serum albumin protein in gel electrophoresis over wide range of other protein(s) is extremely important because it contains more than 60% volume of serum fluid in human body. Given the nonexistence of suitable dye materials for selective staining of serum albumins in gel electrophoresis, we report a new class of easy synthesizable and low molecular weight staining agents based on 3-amino-N-alkyl-carbazole scaffold for selective staining of serum albumins in solid phase. A detailed structure-efficiency relationship (SER) study enabled us to develop two such potent functional molecular probes which stain both human and bovine serum albumin selectively in gel electrophoresis in the presence of other proteins and enzymes. The present gel staining process was found to be very simple and less time-consuming as compared to the conventional coomassie blue staining which in turn makes these probes a new class of serum albumin-specific staining materials in proteome research. Moreover, these molecular lumino-materials can detect serum albumins at subnanomolar level in the presence of broad spectrum of other proteins/enzymes in aqueous buffer (99.9% water, pH = 7.3) keeping the protein secondary structure intact. Our experimental and the docking simulation results show that these probes bind preferentially at 'binding site I' of both the serum proteins. PMID:24926791

Dey, Gourab; Gupta, Abhishek; Mukherjee, Trinetra; Gaur, Pankaj; Chaudhary, Abhishek; Mukhopadhyay, Subhra Kanti; Nandi, Chayan K; Ghosh, Subrata

2014-07-01

138

Influence of fluorescence of bacteria stained with acridine orange on the enumeration of microorganisms in raw milk.  

PubMed

The staining of gram-positive and gram-negative cultures with acridine orange in metabolically active and inactive states was investigated using a Bactoscan, direct epifluorescent filter technique (DEFT), and standard plate count as the reference method. The evaluation of the bacterial cultures in the Bactoscan revealed a linear relationship between Bactoscan counts (pulses) and the quantity of pure culture suspension used. But the proper detection of bacteria with the fluorescence optic methods was dependent on the type of microorganism and the physiological state of the cells. The Bactoscan and DEFT underestimated the bacterial counts of gram-negative cultures as compared with standard plate counting. When stained with acridine orange, metabolically active bacteria showed more orange fluorescence and a lower percentage of green fluorescent cells as compared with inactive bacteria. Bactoscan pulse height analysis (PHA) diagrams, graphs of the detected pulses and their intensity, showed low pulses of inactive bacteria. Many of these weak pulses were eliminated from counting because of their faint fluorescent staining. In contrast, PHA diagrams of metabolically active microorganisms showed bright staining and, therefore, high pulses. A complete count of these bacteria was possible. These investigations point out that discrepancies between the fluorescence optical counting methods and the standard plate count depend strongly on the staining of the cultures with acridine orange and, therefore, on the type of microorganism and the metabolic state of the cells measured. PMID:11132842

Rapposch, S; Zangerl, P; Ginzinger, W

2000-12-01

139

Estrogen receptor-targeted optical imaging of breast cancer cells with near-infrared fluorescent dye  

NASA Astrophysics Data System (ADS)

Molecular imaging provides the in vivo characterization of cellular molecular events involved in normal and pathologic processes. With the advent of optical molecular imaging, specific molecules, proteins and genes may be tagged with a luminescent reporter and visualized in small animals. This powerful new tool has pushed in vivo optical imaging to the forefront as it allows for direct determination of drug bio-distribution and uptake kinetics as well as an indicator of biochemical activity and drug efficacy. Although optical imaging encompasses diverse techniques and makes use of various wavelengths of light, a great deal of excitement in molecular research lies in the use of tomographic and fluorescence techniques to image living tissues with near-infrared (NIR) light. Nonionizing, noninvasive near-infrared optical imaging has great potential to become promising alternative for breast cancer detection. Fluorescence spectroscopy studies of human tissue suggest that a variety of lesions show distinct fluorescence spectra compared to those of normal tissue. It has also been shown that exogenous dyes exhibit selective uptake in neoplastic lesions and may offer the best contrast for optical imaging. Use of exogenous agents would provide fluorescent markers, which could serve to detect embedded tumors in the breast. In particular, the ability to monitor the fluorescent yield and lifetime may also enable biochemical specificity if the fluorophore is sensitive to a specific metabolite, such as oxygen. As a first step, we have synthesized and characterized one such NIR fluorescent dye conjugate, which could potentially be used to detect estrogen receptors (ER)[2] . The conjugate was synthesized by ester formation between 17-? estradiol and a hydrophilic derivative of indocyanine green (ICG) cyanine dye, bis-1, 1-(4-sulfobutyl) indotricarbocyanine-5- carboxylic acid, sodium salt. The ester formed was found to have an extra binding ability with the receptor cites as compared to ICG, which was established by the partition coefficient studies. The replacement of the sodium ion in the ester by a larger glucosammonium ion was found to enhance the hydrophilicity and reduce the toxic effect on the cell lines. The excitation and emission peaks for the conjugate were recorded in the NIR region as 750nm and 788nm respectively. The ester was found nontoxic on adenocarcinoma breast cancer cell lines MCF-7/MDA-MB-231. Specific binding and endocytosis of the estrogen-labeled conjugate was studied on the MCF-7 (ER positive) and MDA-MB-231 (ER negative). Conjugate staining of MCF-7 cells showed ~ 4-fold increase in signal intensity compared to MDA-MB- 231. Further, estrogen molecules were found to be specifically localized to the nuclear region of MCF-7 cells, whereas MDA-MB-231 showed plasma membrane staining. This technique offers the potential of noninvasive detection of hormone receptor status in breast cancer cells and would help in decreasing the load of unnecessary biopsies. Here, we have reported the progress made in the development of a novel NIR external contrast agent and the work is in progress to use this conjugate for the molecular based, diagnostic imaging of breast cancer.

Jose, Iven; Deodhar, Kodand; Chiplunkar, Shuba V.; Patkar, Meena

2010-02-01

140

Photophysical parameters and fluorescence quenching of 7-diethylaminocoumarin (DEAC) laser dye  

Microsoft Academic Search

The optical properties including electronic absorption spectrum, emission spectrum, fluorescence quantum yield, and dipole moment of electronic transition of 7-diethylaminocoumarin (DEAC) laser dye have been measured in different solvents. Both electronic absorption and fluorescence spectra are red shifted as the polarity of the medium increases, indicating that the dipole moment of molecule increases on excitation. The fluorescence quantum yield of

E. H. El-Mossalamy; A. Y. Obaid; S. A. El-Daly

2011-01-01

141

Efficient synthesis of fluorescent-PET probes based on [(18)F]BODIPY dye.  

PubMed

We report the direct conversion of fluorescent probes to PET/fluorescent probes after efficient [(19)F]/[(18)F] exchange at the BODIPY motif. The radiolabeling of a NIR BODIPY dye was also established, which was conjugated with the RGD peptide for PET/fluorescence imaging of integrin expression in vivo. PMID:24869927

Liu, Shuanglong; Li, Dan; Zhang, Zhe; Surya Prakash, G K; Conti, Peter S; Li, Zibo

2014-06-12

142

THERMAL DEPOLARIZATION OF FLUORESCENCE FROM POLYTENE CHROMOSOMES STAINED WITH ACRIDINE ORANGE  

PubMed Central

The degree of polarization of fluorescence from stretched Chironomus thummi polytene chromosomes, stained with low concentrations of acridine orange (AO), decreases with increasing temperature. The "half temperature" of this decrease (T½R) is lower than the expected DNA thermal denaturation temperature (Tm) by about 20°C. T½R is lowered as histone is removed from chromosomes. Balbiani ring regions of the fourth chromosome have T½R's much lower than other regions, and nearly as low as chromosomes which had been extensively pretreated with trypsin to remove histone and other proteins. Measurements of the thermal change in the rotational diffusion rate of AO in solution with DNA indicate that the temperature at which the DNA-AO bonding changes from a "rigid" to a "loose" mode varies with the GC percentage of the DNA, and in the same fashion as Tm, although 20°C lower.

MacInnes, James W.; Uretz, Robert B.

1967-01-01

143

Thermal depolarization of fluorescence from polytene chromosomes stained with acridine orange.  

PubMed

The degree of polarization of fluorescence from stretched Chironomus thummi polytene chromosomes, stained with low concentrations of acridine orange (AO), decreases with increasing temperature. The "half temperature" of this decrease (T((1/2)R)) is lower than the expected DNA thermal denaturation temperature (T(m)) by about 20 degrees C. T((1/2)R) is lowered as histone is removed from chromosomes. Balbiani ring regions of the fourth chromosome have T((1/2)R)'s much lower than other regions, and nearly as low as chromosomes which had been extensively pretreated with trypsin to remove histone and other proteins. Measurements of the thermal change in the rotational diffusion rate of AO in solution with DNA indicate that the temperature at which the DNA-AO bonding changes from a "rigid" to a "loose" mode varies with the GC percentage of the DNA, and in the same fashion as T(m), although 20 degrees C lower. PMID:6036523

MacInnes, J W; Uretz, R B

1967-06-01

144

Fluorescent detection of differentially expressed cDNA using SYBR gold nucleic acid gel stain.  

PubMed

We describe herein a modified differential gene display (DGD) technique that can be rapidly and simply performed and that eliminates the need for radioactivity by fluorescent visualization of complementary deoxyribonucleic acid (cDNA) bands with SYBR gold nucleic acid gel stain. To streamline the DGD procedure, a number of modifications were employed. Ribonucleic acid isolated from differentially treated populations of human trabecular bone-derived mesenchymal progenitor cells was reverse-transcribed into cDNA using oligo-dT primer, and subsequent amplification of differentially expressed cDNAs was done using arbitrary 25-mer primers and oligo-dT9 30-mer primers. Moderate-sized nondenaturing 6% polyacrylamide gels (30 x 20 cm) of 1.5-mm thickness were used for easier handling and increased sample loading capacity. Gels were subjected to electrophoresis overnight, stained with SYBR gold, and visualized and photographed using a commercially available gel imager. DNA bands ranging in size from 100 to 400 bp were visualized directly on an ultraviolet transilluminator, excised from the gel, and reamplified. The cDNA amplicons were subcloned, sequenced, and gene sequences were identified by a Basic Local Alignment Search Tool of genomic databases. Overall, this rapid and functional method proved quite effective for identification of novel genes that may be of interest in studies of cartilage and bone differentiation. PMID:15456962

Danielson, Keith G; Kanthala, Shirisha; Tuli, Richard; Tuan, Rocky S

2004-09-01

145

[Differential staining of hamadryas baboon chromosomes with Romanovsky-Giemsa dye (G-discs)].  

PubMed

The pattern of G-discs in the chromosomes of baboon (Papio hamadryas) was studied after staining by means of ASG method. On the basis of these data all the 20 pairs of autosomes and sex chromosomes were identified. According to the distinctness of the discs all the chromosomes were classified into 3 groups: well differentiated, faintly differentiated and moderately differentiated. The most distinct pattern of discs was obtained in slightly spiralized chromosomes. Dimorphism of the disc pattern in homologous chromosomes was observed, which is, possibly, indicative of their different functional activity. PMID:56287

Markarian, D S

1975-01-01

146

Method and apparatus for staining immobilized nucleic acids  

SciTech Connect

A method for staining immobilized nucleic acids includes the following steps: affixing DNA probes to a solid substrate; moving target DNA material into proximity with the DNA probes, whereby the target DNA hybridized with specific ones of the DNA probes; and moving a fluorescent dye into proximity with the hybridized target DNA, whereby the fluorescent dye binds to the hybridized DNA to enable subsequent detection of fluorescence.

Ramsey, J.M.; Foote, R.S.; Jacobson, S.C.

2000-05-02

147

Method and apparatus for staining immobilized nucleic acids  

DOEpatents

A method for staining immobilized nucleic acids includes the steps of affixing DNA probes to a solid substrate, moving target DNA material into proximity with the DNA probes, whereby the target DNA hybridized with specific ones of the DNA probes, and moving a fluorescent dye into proximity with the hybridized target DNA, whereby the fluorescent dye binds to the hybridized DNA to enable subsequent detection of fluorescence.

Ramsey, J. Michael (Knoxville, TN); Foote, Robert S. (Oak Ridge, TN); Jacobson, Stephen C. (Knoxville, TN)

2000-01-01

148

Propidium iodide staining: a new application in fluorescence microscopy for analysis of cytoarchitecture in adult and developing rodent brain.  

PubMed

Immunohistochemical visualization of antigens in specimen has evolved to an indispensable technique in biomedical research for investigations of cell morphology and pathology both in bright field and fluorescence microscopy. While there are couple of staining methods that reveal entire cytoarchitecture in bright field microscopy such as Nissl or hemalaun-eosin, there are still limitations in visualizations of cytoarchitecture in fluorescence microscopy. The present study reports a simple staining method that provides the required illustration of cell allocations and cellular composition in fluorescence microscopy in adult and in developing rodent central nervous system using the fluorophore propidium iodide (PI, 5?g/mL). PI is a well-accepted marker for degenerating cells when applied prior to fixation (pre-fixation PI staining). Here, PI was added to the sections after the fixation (post-fixation PI staining). This revised labeling procedure led to similar cytoarchitectural staining patterns in fluorescence microscopy as observed with hemalaun in bright field microscopy. This finding was proven in organotypic hippocampal slice cultures (OHSC) and brain sections obtained from different postnatal developmental stages. Excitotoxically lesioned OHSC subjected to pre-fixation PI staining merely showed brightly labeled condensed nuclei of degenerating neurons. In contrast, post-fixation PI staining additionally revealed extensive labeling of neuronal cell bodies and glial cells within the OHSC, thus allowing visualization of stratification of neuronal layers and cell morphology. Furthermore, post-fixation PI staining was combined with NeuN, calbindin, calretinin, glial fibrillary acidic protein or Griffonia simplicifolia isolectin B4 (IB(4)) in post natal (p1 and p9) and adult rats. In early post-natal brain sections almost all mentioned cellular markers led to an incomplete staining of the native cell organization and resulted in an inaccurate estimation of cell morphology when compared to adult brains. In contrast, post-fixation PI staining allowed investigation of the whole cytoarchitecture independent of the developmental stage. Taken together, post-fixation PI staining provides a detailed insight in the morphology of both developing and adult brain tissues in fluorescence microscopy. PMID:22579654

Hezel, Marcus; Ebrahimi, Fahim; Koch, Marco; Dehghani, Faramarz

2012-10-01

149

Fluorescent DNA nanotags featuring covalently attached intercalating dyes: synthesis, antibody conjugation, and intracellular imaging.  

PubMed

We have synthesized fluorescent DNA duplexes featuring multiple thiazole orange (TO) intercalating dyes covalently attached to the DNA via a triazole linkage. The intercalating dyes stabilize the duplex against thermal denaturation and show bright fluorescence in the green region of the spectrum. The emission color can be changed to orange or red by addition of energy-accepting Cy3 or Cy5 dyes attached covalently to the DNA duplex. The dye-modified DNA duplexes were then attached to a secondary antibody for intracellular fluorescence imaging of centrosomes in Drosophila embryos. Bright fluorescent foci were observed at the centrosomes in both the donor (TO) and acceptor (Cy5) channels, because the energy transfer efficiency is moderate. Monitoring the Cy5 emission channel significantly minimized the background signal because of the large shift in emission wavelength allowed by energy transfer. PMID:21755981

Stadler, Andrea L; Delos Santos, Junriz O; Stensrud, Elizabeth S; Dembska, Anna; Silva, Gloria L; Liu, Shengpeng; Shank, Nathaniel I; Kunttas-Tatli, Ezgi; Sobers, Courtney J; Gramlich, Philipp M E; Carell, Thomas; Peteanu, Linda A; McCartney, Brooke M; Armitage, Bruce A

2011-08-17

150

Fluorescent DNA Nanotags Featuring Covalently Attached Intercalating Dyes: Synthesis, Antibody Conjugation and Intracellular Imaging  

PubMed Central

We have synthesized fluorescent DNA duplexes featuring multiple thiazole orange (TO) intercalating dyes covalently attached to the DNA via a triazole linkage. The intercalating dyes stabilize the duplex against thermal denaturation and show bright fluorescence in the green. The emission color can be changed to orange or red by addition of energy-accepting Cy3 or Cy5 dyes attached covalently to the DNA duplex. The dye-modified DNA duplexes were then attached to a secondary antibody for intracellular fluorescence imaging of centrosomes in Drosophila embryos. Bright fluorescent foci were observed at the centrosomes in both the donor (TO) and acceptor (Cy5) channels, due to the fact that the energy transfer efficiency is moderate. Monitoring the Cy5 emission channel significantly minimized the background signal due to the large shift in emission wavelength allowed by energy transfer.

Stadler, Andrea L.; Santos, Junriz Delos; Stensrud, Elizabeth S.; Dembska, Anna; Silva, Gloria L.; Liu, Shengpeng; Shank, Nathaniel I.; Kunttas-Tatli, Ezgi; Sobers, Courtney J.; Gramlich, Philipp M. E.; Carell, Thomas; Peteanu, Linda A.; McCartney, Brooke M.; Armitage, Bruce A.

2011-01-01

151

pH-Dependence of the Absorption and Fluorescent Properties of Fluorone Dyes in Aqueous Solutions  

NASA Astrophysics Data System (ADS)

A series of fluorone dyes (fluorescein, eosin Y, erythrosin B) in aqueous solution is investigated by the absorption, fluorescence spectroscopic and time-resolved methods. Based on an analysis of the absorption spectrum amplitude, the fluorescence quantum yield, and the fluorescence lifetime vs. pH, the dissociation constants of the dyes in the ground and excited states are calculated. Quantitative and qualitative differences in the character of ionic equilibrium between fluorescein and its halogenated derivatives - eosin Y and erythrosin B - are revealed. The polarized fluorescence method has shown that the hydrodynamic diameter changes in a series of fluorone dyes due to both the increase of the bond length upon halogenation and the influence of solvation shell upon the change of the dye ionic species.

Slyusareva, E. A.; Gerasimova, M. A.

2014-04-01

152

Rapid Enumeration of Active Legionella pneumophila in Freshwater Environments by the Microcolony Method Combined with Direct Fluorescent Antibody Staining  

PubMed Central

In this study, a microcolony technique was combined with direct fluorescent antibody staining for the specific detection and enumeration of Legionella pneumophila in freshwater samples with growth activity. This method allowed the detection of active L. pneumophila (within 48 h) in 91 bath water samples collected from 30 bathing facilities, with similar sensitivity of a conventional plate-counting method. These results suggest that the microcolony method combined with fluorescent antibody staining could be useful as a monitoring technique for the prevention of Legionnaires’ disease through the early detection of L. pneumophila in freshwater.

Baba, Takashi; Inoue, Naoko; Yamaguchi, Nobuyasu; Nasu, Masao

2012-01-01

153

Demonstration of immune complex deposits using fluorescence microscopy of hematoxylin and eosin-stained sections of Hollande's fixed renal biopsies.  

PubMed

A new method that may be useful in the evaluation of renal biopsies is described using fluorescence microscopy on standard hematoxylin and eosin-stained sections of kidney tissue fixed in Hollande's fixative. We describe brightly fluorescing immune complex deposits within glomerular basement membranes and mesangial matrices that correlate well with the results of standard direct immunofluorescence on frozen tissue and electron microscopy. In a blind analysis of 261 consecutive renal biopsies, we determine that this method has diagnostic utility for identification of immune complex glomerulonephritis and significantly extends the usefulness of standard histologic preparations before the use of special stains or procedures. PMID:12218217

McMahon, James T; Myles, Jonathan L; Tubbs, Raymond R

2002-09-01

154

Argon-pumped tunable dye laser therapy for facial port-wine stain hemangiomas in adults--a new technique using small spot size and minimal power  

Microsoft Academic Search

A low power, argon-pumped tunable dye laser was used to deliver yellow light of 577 nm. Individual blood vessels within port-wine stain hemangiomas were treated with a 0.1-mm beam of light using 8 X magnification. This technique permits excellent resolution of facial and nuchal port-wine stain hemangiomas in adults without the adverse complications of textural change, permanent pigmentation abnormality, or

A. Scheibner; R. G. Wheeland

1989-01-01

155

Argon-pumped tunable dye laser therapy for facial port-wine stain hemangiomas in adults--a new technique using small spot size and minimal power  

SciTech Connect

A low power, argon-pumped tunable dye laser was used to deliver yellow light of 577 nm. Individual blood vessels within port-wine stain hemangiomas were treated with a 0.1-mm beam of light using 8 X magnification. This technique permits excellent resolution of facial and nuchal port-wine stain hemangiomas in adults without the adverse complications of textural change, permanent pigmentation abnormality, or hypertrophic scarring.

Scheibner, A.; Wheeland, R.G.

1989-03-01

156

Rapid viability assessment of yeast cells using vital staining with 2-NBDG, a fluorescent derivative of glucose.  

PubMed

A fluorescent glucose analogue, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG), which had been developed previously for the analysis of glucose uptake activity by living cells, was investigated to evaluate its applicability for assaying the viability of yeasts. Fluorescence intensities of the yeast population were measured by fluorescence spectrophotometry upon exposure to antifungal agents after staining with 2-NBDG and were compared to the number of colony forming units (CFU). A good correlation was obtained between the yeast viability, determined by the CFU, and the accumulation of 2-NBDG by yeast cells (correlation constant: r=0.98). Susceptibility testing of amphotericin B and miconazole against yeast strains by plate count and 2-NBDG fluorescence method yielded corresponding results. In conclusion, we found that staining with 2-NBDG is a rapid and sensitive method for the assessment of yeast cell viability. PMID:12038577

Oh, Ki-Bong; Matsuoka, Hideaki

2002-06-01

157

Time-resolved laser-induced fluorescence study on dyes used in DNA sequencing  

SciTech Connect

Research on the time-resolved fluorescence of fluorescein isothiocyanate, NBD, tetramethylrhodamine isothiocyanate, and Texas Red - the dyes used for fluorescence-based DNA sequencing - is described. Mean fluorescence lifetiems in both aqueous buffer solution and 5.3%T, 4.8%C polyacrylamide gel were determined as a function of excitation wave-lengths at 337, 470, and 550 nm and were found to be 3.5, 1.1, 2.5, and 4.3 ns; the detection limits are 10, 200, 200 and 200 amol for FITC, NBD, TEMR, and T. Red, respectively. Comparisons of fluorescence parameters between the conjugated dyes and the free dyes are also reported. Results on the optimization of the excitation source wavelengths to improve sensitivity and reduce background scattering in polyacrylamide gel are also reported. Time-resolved fluorescence was successfully applied to resolve spectral overlapping of emissions in both solution and in polyacrylamide gel. 12 refs., 6 figs., 1 tab.

Chang, Kaisyang; Force, R.K. (Univ. of Rhode Island, Kingston (United States))

1993-01-01

158

Enhanced fluorescence from dye molecules by Au nanoparticles on asymmetric double-stranded DNA and mechanism  

NASA Astrophysics Data System (ADS)

Gold nanoparticles (NPs) prepared on asymmetric DNA double helical structures show some twinning structures and sharp corners because of the low processing temperature. The distance between individual NPs varies between 2 and 4 nm, and these NPs form clusters with a size of ˜40 nm. The DNA structures also provide docking sites for the fluorescent dye. The dependence of the fluorescence enhancement on the distance between the NPs and dye molecules is investigated. The maximum enhancement factor is 5.8 when the distance between the dye and Au NP surface is 3.4 nm and the results are consistent with theoretical simulation.

Guo, J. H.; Liu, L. Z.; Zhu, X. B.; Wu, X. L.; Chu, Paul K.

2014-04-01

159

Promising fluorescent dye for solar energy conversion based on a perylene perinone.  

PubMed

We describe the synthesis of a dye based on a perylene perinone and evaluate its potential as the functional material for use in the luminescent solar concentrator (LSC). The dye extends the absorption wavelength of LSCs using the perylene-based dye Lumogen Red 305 by more than ~50 nm, translating into the collection of potentially 25% more photons at a reasonable fluorescent quantum yield and photostability. When the new perinone is used in a two-waveguide LSC in conjunction with Red 305, the integrated edge emission of the total LSC system may be increased more than 24% when compared to the Red 305 dye alone. PMID:21221140

Debije, Michael G; Verbunt, Paul P C; Nadkarni, Pradeep J; Velate, Suresh; Bhaumik, Kankan; Nedumbamana, Sankaran; Rowan, Brenda C; Richards, Bryce S; Hoeks, Theo L

2011-01-10

160

A double fluorescence staining protocol to determine the cross-sectional area of myofibers using image analysis.  

PubMed

A double fluorescence staining protocol was developed to facilitate computer based image analysis. Myofibers from experimentally treated (irradiated) and control growing turkey skeletal muscle were labeled with the anti-myosin antibody MF-20 and detected using fluorescein-5-isothiocyanate (FITC). Extracellular material was stained with concanavalin A (ConA)-Texas red. The cross-sectional area of the myofibers was determined by calculating the number of pixels (0.83 mu m(2)) overlying each myofiber after subtracting the ConA-Texas red image from the MF-20-FITC image for each region of interest. As expected, myofibers in the irradiated muscle were smaller (P < 0.05) than those in the non-irradiated muscle. This double fluorescence staining protocol combined with image analysis is accurate and less labor-intensive than classical procedures for determining the cross-sectional area of myofibers. PMID:9138529

Mozdziak, P E; Fassel, T A; Schultz, E; Greaser, M L; Cassens, R G

1996-03-01

161

A double fluorescence staining protocol to determine the cross-sectional area of myofibers using image analysis  

NASA Technical Reports Server (NTRS)

A double fluorescence staining protocol was developed to facilitate computer based image analysis. Myofibers from experimentally treated (irradiated) and control growing turkey skeletal muscle were labeled with the anti-myosin antibody MF-20 and detected using fluorescein-5-isothiocyanate (FITC). Extracellular material was stained with concanavalin A (ConA)-Texas red. The cross-sectional area of the myofibers was determined by calculating the number of pixels (0.83 mu m(2)) overlying each myofiber after subtracting the ConA-Texas red image from the MF-20-FITC image for each region of interest. As expected, myofibers in the irradiated muscle were smaller (P < 0.05) than those in the non-irradiated muscle. This double fluorescence staining protocol combined with image analysis is accurate and less labor-intensive than classical procedures for determining the cross-sectional area of myofibers.

Mozdziak, P. E.; Fassel, T. A.; Schultz, E.; Greaser, M. L.; Cassens, R. G.

1996-01-01

162

Polarization and Symmetry of Electronic Transitions in Long Fluorescence Lifetime Triangulenium Dyes  

PubMed Central

To fully exploit the capabilities of fluorescence probes in modern experiments, where advanced instrumentation is used to probe complex environments, other photophysical properties than emission color and emission intensity are monitored. Each dye property can be addressed individually as well as collectively to provide in-depth information unavailable from the standard intensity measurements. Dyes with long emission lifetimes and strongly polarized transitions enable the monitoring of lifetime changes as well as emission polarization (or anisotropy). Thus experiments can be designed to follow slow dynamics. In this article the UV and visible electronic transitions of a series of red emitting dyes based on the triangulenium motif are investigated. We resolve overlapping features in the spectra and assign transition moment of the molecular axes. The result is the complete Jablonski diagram for the UV and visible spectral region. The symmetries of the studied dyes are shown to have a large influence on the optical response and they are clearly separated into two groups of symmetry by their photophysical properties. The C2v symmetric dyes: azadioxatriangulenium (ADOTA+) and diazaoxatriangulenium (DAOTA+) have high emission anisotropies, fluorescence lifetimes around 20 ns, and fluorescence quantum yields of ~50%. The trioxatriangulenium (TOTA+) and triazatriangulenium (TATA+) dyes—nominally of D3h symmetry—have fluorescence lifetimes around 10 ns lifetimes and fluorescence quantum yields of 10-15%. However, the D3h-symmetry is shown to be lowered to a point group, where the axes transform uniquely such that the degeneracy of the E’-states is lifted.

Thyrhaug, Erling; S?rensen, Thomas Just; Gryczynski, Ignacy; Gryczynski, Zygmunt; Laursen, Bo W.

2013-01-01

163

Automated quality assessment of autonomously acquired microscopic images of fluorescently stained bacteria.  

PubMed

Quality assessment of autonomously acquired microscopic images is an important issue in high-throughput imaging systems. For example, the presence of low quality images (>or=10%) in a dataset significantly influences the counting precision of fluorescently stained bacterial cells. We present an approach based on an artificial neural network (ANN) to assess the quality of such images. Spatially invariant estimators were extracted as ANN input data from subdivided images by low level image processing. Different ANN designs were compared and >400 ANNs were trained and tested on a set of 25,000 manually classified images. The optimal ANN featured a correct identification rate of 94% (3% false positives, 3% false negatives) and could process about 10 images per second. We compared its performance with the image quality assessment by different humans and discuss the difficulties in assigning images to the correct quality class. The computer program and the documented source code (VB.NET) are provided under General Public Licence. PMID:19821518

Zeder, M; Kohler, E; Pernthaler, J

2010-01-01

164

A sensitive method for confocal fluorescence microscopic visualization of starch granules in iodine stained samples  

PubMed Central

Synthesized by glycogen synthase and starch synthases (SS) using ADP-glucose as the sugar donor molecule, glycogen and starch accumulate as predominant storage carbohydrates in most bacteria and plants, respectively. We have recently shown that the so-called “starch-less” Arabidopsis thaliana adg1–1 and aps1 mutants impaired in ADP-glucose pyrophosphorylase do indeed accumulate low starch content in normal growth conditions, and relatively high starch content when plants were cultured in the presence of microbial volatiles. Our results were strongly supported by data obtained using a highly sensitive method for confocal fluorescence microscopic visualization of iodine stained starch granules. Using Arabidopsis leaves from WT plants, aps1 plants, ss3/ss4 plants lacking both class III and class IV SS, gbss plants lacking the granule-bound SS, and sus1/sus2/sus3/sus4 plants lacking four genes that code for proteins with sucrose synthase activity, in this work we precisely describe the method for preparation of plant samples for starch microscopic examination. Furthermore, we show that this method can be used to visualize glycogen in bacteria, and pure starch granules, amylose and amylopectin.

Ovecka, Miroslav; Bahaji, Abdellatif; Munoz, Francisco Jose; Almagro, Goizeder; Ezquer, Ignacio; Baroja-Fernandez, Edurne; Li, Jun; Pozueta-Romero, Javier

2012-01-01

165

Fluorescent measurements in whole blood and plasma using red-emitting dyes  

Microsoft Academic Search

We have determined the fluorescence characteristics of albumin blue 670 and Rhodamine 800 in plasma and blood in order to test the feasibility of making direct fluorescence sensing measurements in blood. These dyes were used because of their absorption in the red\\/NIR where absorption by hemoglobin is minimized. Front face illumination and detection was used to minimize absorption and scattering

Omoefe O. Abugo; Petr Herman; Joseph R. Lakowicz

2000-01-01

166

Fluorescence Energy Transfer Dye-Labeled Primers for DNA Sequencing and Analysis  

Microsoft Academic Search

Fluorescent dye-labeled DNA primers have been developed that exploit fluorescence energy transfer (ET) to optimize the absorption and emission properties of the label. These primers carry a fluorescein derivative at the 5' end as a common donor and other fluorescein and rhodamine derivatives attached to a modified thymidine residue within the primer sequence as acceptors. Adjustment of the donor-acceptor spacing

Jingyue Ju; Chihchuan Ruan; Carl W. Fuller; Alexander N. Glazer; Richard A. Mathies

1995-01-01

167

Ion association reactions with biological membranes, studied with the fluorescent dye 1-anilino-8-naphthalenesulfonate  

Microsoft Academic Search

Summary (1) When salts are added to buffered suspensions of membrane fragments containing the fluorochrome 1-anilino-8-naphthalenesulfonate (ANS), there is an increased fluorescence. This is caused by increased binding of the fluorochrome; the intrinsic fluorescence characteristics of the bound dye remain unaltered. These properties make ANS a sensitive and versatile indicator of ion association equilibria with membranes. (2) Alkali metal and

Bastien Gomperts; Frédéric Lantelme; Reinhard Stock

1970-01-01

168

Uniform Band Intensities in Fluorescent Dye Terminator Sequencing  

Microsoft Academic Search

The use of Cyanine dye (Cy 5 and Cy5.5) labeled dideoxy terminators with Thermo Sequenase DNA polymerase in DNA sequencing provides uniform band intensity, improved sequence read-length, and accuracy. It also greatly improves the ability to detect single base heterozygotes with dye-terminator sequencing method.

Shiv Kumar; C. W. Fuller; S. Nampalli; M. Khot; I. Livshin; L. Sun; S. B. Samols; J. A. Mamone; K. M. Hujer; B. F. McArdle; J. R. Nelson; S. Duthie

1999-01-01

169

Excimer laser pumped dye laser for fluorescence decay time measurement  

SciTech Connect

A simple method is proposed for short fall-time dye laser pulse generation. The pulse tailoring is demonstrated by an excimer laser pumped double cavity dye laser. The achieved fall time is 280 ps with the use of a 7 ns long pump pulse.

Bor, Z.; Raksi, F.; Kovacs, G.; Racz, B.

1988-05-01

170

Use of fluorescent NIR dyes in silica nanoparticles and as enzyme substrates in bioanalytical applications  

NASA Astrophysics Data System (ADS)

Near-Infrared (NIR) absorbing carbocyanine dyes have been increasingly used in analytical, biological and medical fields as they can be useful for developing bioanalytical and biomedical methods. The utilization of the NIR spectral region (650-900 nm) is advantageous and is due to the inherently lower background interference and the high molar absorptivities of NIR chromophores. NIR dyes typically have relatively lower fluorescent quantum yield as compared to visible fluorophores, but much higher molar absorptivities which more than compensates for the lower quantum yields regarding detection limits. Fluorescence intensity of NIR dyes significantly increases by enclosing several dye molecules in silica nanoparticles. Self quenching may become a problem for carbocyanines at such high concentrations that may be present in the silica nanoparticles. Dyes that have large Stokes' shift can significantly decrease this problem. Increased Stokes' shift for carbocyanines dyes can be achieved by substituting meso position halogens with a linker containing aliphatic or aromatic amino moiety which also serves as a covalent linker for attaching the dye molecule to the nanoparticle backbone. The primary applications of these particles are for bright fluorescent labels to be used in bioanalytical applications such as immunochemistry, flow cytometry, etc. This work also discusses the use of NIR dyes as enzyme substrates. NIR dyes can be used as enzyme substrates and hence for characterization of enzyme activity. The well characterized alkenesulfonate monooxygenase enzyme was chosen for these studies. Carbocyanines containing alkylsulfonate moieties do not exhibit significant fluorescence change upon binding to biomolecules however otherwise identical NIR dye analogs that contain alkylaldehyde moiety at the same position do exhibit changes which can be utilized for characterization of alkenesulfonate monooxygenase enzyme activity using near infrared dyes as substrates. In this study a new class of sulfonated penta- and heptamethine dyes were used as substrates in vitro utilizing a photo-reduced riboflavin mononucleotide (FMN) with a glucose/ glucose-oxygenase oxygen scavenging system. Laser Induced Fluorescence (LIF) detected CZE was utilized to detect the sulfonated and de-sulfonated carbocyanines. The lower fluorescence quantum yield of the less water soluble alkylaldehyde analogs was detected and enzyme activity was characterized.

Patonay, Gabor; Chapman, Gala; Beckford, Garfield; Henary, Maged; Ellis, Holly

2014-03-01

171

Evaluation of Polymethine Dyes as Potential Probes for Near Infrared Fluorescence Imaging of Tumors: Part - 1  

PubMed Central

Near-infrared (NIR) organic dyes have become important for many biomedical applications, including in vivo optical imaging. Conjugation of NIR fluorescent dyes to photosensitizing molecules (photosensitizers) holds strong potential for NIR fluorescence image guided photodynamic therapy (PDT) of cancer. Therefore, we were interested in investigating the photophysical properties, in vivo tumor-affinity and fluorescence imaging potential of a series of heterocyclic polymethine dyes, which could then be conjugated to certain PDT agents. For our present study, we selected a series of symmetrical polymethine dyes containing a variety of bis-N-substituted indole or benzindole moieties linked by linear conjugation with and without a fused substituted cyclohexene ring. The N-alkyl side chain at the C-terminal position was functionalized with sulfonic, carboxylic acid, methyl ester or hydroxyl groups. Although, among the parent cyanine dyes investigated, the commercially available, cyanine dye IR783 (3) (bis-indole-N-butylsulfonate)-polymethine dye with a cyclic chloro-cyclohexene moiety showed best fluorescence-imaging ability, based on its spectral properties (?Abs=782 nm, ?Fl=810 nm, ? = 261,000 M-1cm-1, ?Fl?0.08) and tumor affinity. In addition to 3, parent dyes IR820 and Cypate (6) were also selected and subjected to further modifications by introducing desired functional groups, which could enable further conjugation of the cyanine dyes to an effective photosensitizer HPPH developed in our laboratory. The synthesis and biological studies (tumor-imaging and PDT) of the resulting bifunctional conjugates are discussed in succeeding paper (Part-2 of this study).

James, Nadine S.; Chen, Yihui; Joshi, Penny; Ohulchanskyy, Tymish Y.; Ethirajan, Manivannan; Henary, Maged; Strekowsk, Lucjan; Pandey, Ravindra K

2013-01-01

172

Evaluation of polymethine dyes as potential probes for near infrared fluorescence imaging of tumors: part - 1.  

PubMed

Near-infrared (NIR) organic dyes have become important for many biomedical applications, including in vivo optical imaging. Conjugation of NIR fluorescent dyes to photosensitizing molecules (photosensitizers) holds strong potential for NIR fluorescence image guided photodynamic therapy (PDT) of cancer. Therefore, we were interested in investigating the photophysical properties, in vivo tumor-affinity and fluorescence imaging potential of a series of heterocyclic polymethine dyes, which could then be conjugated to certain PDT agents. For our present study, we selected a series of symmetrical polymethine dyes containing a variety of bis-N-substituted indole or benzindole moieties linked by linear conjugation with and without a fused substituted cyclohexene ring. The N-alkyl side chain at the C-terminal position was functionalized with sulfonic, carboxylic acid, methyl ester or hydroxyl groups. Although, among the parent cyanine dyes investigated, the commercially available, cyanine dye IR783 (3) (bis-indole-N-butylsulfonate)-polymethine dye with a cyclic chloro-cyclohexene moiety showed best fluorescence-imaging ability, based on its spectral properties (?Abs=782 nm, ?Fl=810 nm, ? = 261,000 M(-1)cm(-1), ?Fl?0.08) and tumor affinity. In addition to 3, parent dyes IR820 and Cypate (6) were also selected and subjected to further modifications by introducing desired functional groups, which could enable further conjugation of the cyanine dyes to an effective photosensitizer HPPH developed in our laboratory. The synthesis and biological studies (tumor-imaging and PDT) of the resulting bifunctional conjugates are discussed in succeeding paper (Part-2 of this study). PMID:24019854

James, Nadine S; Chen, Yihui; Joshi, Penny; Ohulchanskyy, Tymish Y; Ethirajan, Manivannan; Henary, Maged; Strekowsk, Lucjan; Pandey, Ravindra K

2013-01-01

173

Selective fluorescent Hg(II) detection in aqueous solutions with a dye intermediate  

Microsoft Academic Search

A dye intermediate, 1-amino-8-naphthol-3,6-disulfonic acid sodium (ANDS) was first used to selectively recognize Hg(II) in aqueous solutions with its fluorescence being strong quenched. The fluorescence quenching of ANDS was attributed to the formation of an inclusion complex between Hg(II) and ANDS by 2:1 complex ratio (K=6.2×109), which has been utilized as the basis of the fabrication of the Hg(II)-sensitive fluorescent

Song Young

2007-01-01

174

An improved technique for selective silver staining of nucleolar organizer regions in human chromosomes  

Microsoft Academic Search

A reliable technique for staining human chromosomal nucleolar organizers (NOR's) with silver solutions is described. The NOR's can be selectively stained dark brown by silver solutions leaving the chromosome arms unstained and available for counterstaining with orcein or Giemsa dyes. Unequivocal identification of chromosome pairs bearing NOR's can be achieved using fluorescent banding techniques followed by silver staining. The silver

S. E. Bloom; C. Goodpasture

1976-01-01

175

Green Tea Catechins Quench the Fluorescence of Bacteria-Conjugated Alexa Fluor Dyes  

PubMed Central

Accumulating evidence suggests that Green tea polyphenolic catechins, especially the (-)-epigallocatechin gallate (EGCG), can be cross-linked to many proteins, and confer a wide range of anti-bacterial activities possibly by damaging microbial cytoplasmic lipids and proteins. At the doses that conferred protection against lethal polymicrobial infection (induced by cecal ligation and puncture), EGCG significantly reduced bacterial loads particularly in the liver and lung. To elucidate its bactericidal mechanisms, we determined whether EGCG affected the fluorescence intensities of bacteria-conjugated Alexa Fluor 488 or 594 dyes. When mixed with unconjugated Alexa Fluor 488 or 594 dyes, EGCG or analogs did not affect the fluorescence intensity of these dyes. In a sharp contrast, EGCG and some analogs (e.g., Catechin Gallate, CG), markedly reduced the fluorescence intensity of Gram-positive Staphylococcus aureus-conjugated Alexa 594 and Gram-negative Escherichia coli-conjugated Alexa 488. Interestingly, co-treatment with ethanol impaired the EGCG-mediated fluorescence quenching of the G+ S. aureus, but not of the G- E. coli-conjugated Alexa Flour dyes. In light of the notion that Alexa Fluor dyes can be quenched by aromatic amino acids, it is plausible that EGCG exerts anti-microbial activities possibly by altering microbial protein conformations and functions. This possibility can now be explored by screening other fluorescence-quenching agents for possible antimicrobial activities.

Zhao, Lin; Li, Wei; Zhu, Shu; Tsai, Sheena; Li, Jianhua; Tracey, Kevin J.; Wang, Ping; Fan, Saijun; Sama, Andrew E.; Wang, Haichao

2013-01-01

176

Room Temperature Single-Photon Source: Single-Dye Molecule Fluorescence in Liquid Crystal Host  

SciTech Connect

OAK-(B204)We report on new approaches toward an implementation of an efficient, room temperature, deterministically polarized, single-photon source (SPS) on demand-a key hardware element for quantum information and quantum communication. Operation of a room temperature SPS is demonstrated via photon antibunching in the fluorescence from single terrylene-dye molecules embedded in a cholesteric liquid crystal host. Using oxygen-depleted liquid crystal hosts, dye-bleaching was avoided over the course of more than 1 h of continuous 532-nm excitation. Liquid crystal hosts (including liquid crystal oligomers/polymers) permit further increase of the efficiency of the source: (1) by aligning the dye molecules along a direction preferable for the maximum excitation efficiency; (2) by tuning a one-dimensional (1-D) photonic-band-gap microcavity of planar-aligned cholesteric (chiral nematic) liquid crystal layer to the dye fluorescence band.

Lukishova, S.G.; Schmid, A.W.; McNamara, A.J.; Boyd, R.W.; Stroud, C.R.Jr.

2003-12-31

177

Application of potential-sensitive fluorescent dyes in anion and cation-sensitive polymer membranes  

Microsoft Academic Search

The applicability of two potential-sensitive dyes (PSDs) for optical sensing of ions is reported. In particular, nitrate and nitrite-responsive as well as potassium and mercury-sensitive polymer membranes have been developed. In general, membranes are composed of a plasticized polymer, an ion carrier and a fluorescent dye which optically transduces the extraction of the analyte ion in the polymer matrix. The

Gerhard J. Mohr; Ivana Murkovic; Frank Lehmann; Christian Haider; Otto S. Wolfbeis

1997-01-01

178

Photophysics of Laser Dye-Doped Polymer Membranes for Laser-Induced Fluorescence Photogrammetry  

NASA Technical Reports Server (NTRS)

Laser-induced fluorescence target generation in dye-doped polymer films has recently been introduced as a promising alternative to more traditional photogrammetric targeting techniques for surface profiling of highly transparent or reflective membrane structures. We investigate the photophysics of these dye-doped polymers to help determine their long-term durability and suitability for laser-induced fluorescence photogrammetric targeting. These investigations included experimental analysis of the fluorescence emission pattern, spectral content, temporal lifetime, linearity, and half-life. Results are presented that reveal an emission pattern wider than normal Lambertian diffuse surface scatter, a fluorescence time constant of 6.6 ns, a pump saturation level of approximately 20 micro J/mm(exp 2), and a useful lifetime of more than 300,000 measurements. Furthermore, two demonstrations of photogrammetric measurements by laser-induced fluorescence targeting are presented, showing agreement between photogrammetric and physically measured dimensions within the measurement scatter of 100 micron.

Dorrington, Adrian A.; Jones, Thomas W.; Danehy, Paul M.

2004-01-01

179

Adsorption kinetics of a fluorescent dye in a long chain fatty acid matrix  

NASA Astrophysics Data System (ADS)

This work reports the adsorption kinetics of a highly fluorescent laser dye rhodamine B (RhB) in a preformed stearic acid (SA) Langmuir monolayer. The reaction kinetics was studied by surface pressure-time ( ?- t) curve at constant area and in situ fluorescence imaging microscopy (FIM). Increase in surface pressure (at constant area) with time as well as increase in surface coverage of monolayer film at air-water interface provide direct evidence for the interaction. ATR-FTIR spectra also supported the interaction and consequent complexation in the complex films. UV-vis absorption and Fluorescence spectra of the complex Langmuir-Blodgett (LB) films confirm the presence of RhB molecules in the complex films transferred onto solid substrates. The outcome of this work clearly shows successful incorporation of RhB molecules into SA matrix without changing the photophysical characteristics of the dye, thus making the dye material as LB compatible.

Hussain, Syed Arshad; Banik, Soma; Chakraborty, S.; Bhattacharjee, D.

2011-09-01

180

The role of rare earth oxide nanoparticles in suppressing the photobleaching of fluorescent organic dyes  

NASA Astrophysics Data System (ADS)

Organic dyes are widely used for both industrial as well as in scientific applications such as the fluorescent tagging of materials. However the process of photobleaching can rapidly degrade dye fluorescence rendering the material non-functional. Thus exploring novel methods for preventing photobleaching can have widespread benefits. In this work we show that the addition of minute quantities of rare earth (RE) oxide nanoparticles can significantly suppress the photobleaching of dyes. The fluorescence of Rhodamine and AlexaFluor dyes was measured as a function of time with and without the addition of CeO2 and La2O3 nanoparticle additives (two RE oxides that contain an oxygen vacancy based defect structure), as well as with FeO nanoparticles (which has an oxygen excess stoichiometry). We find that the rare earth oxides significantly prolonged the lifetimes of the dyes. The results allow us to develop a model based upon the presence of oxygen vacancies defects that allow the RE oxides to act as oxygen scavengers. This enables the RE oxide particles to effectively remove reactive oxygen free radicals generated in the dye solutions during the photoabsorption process.

Guha, Anubhav; Basu, Anindita

2013-03-01

181

Relationship between stallion sperm motility and viability as detected by two fluorescence staining techniques using flow cytometry.  

PubMed

Relationships between sperm motility parameters and viability were evaluated using two fluorescent staining techniques in fresh extended semen (fresh and after 24 h storage at 5 degrees C) that had various concentrations of dead sperm added to simulate different levels of viable and nonviable sperm. Both protocols incorporated SYBR-14 and propidium iodide (PI) while the second protocol added the mitochondrial probe JC-1. The relationship between total sperm motility and percent viable sperm was high between staining protocols (r = 0.98). Time (0 h versus 24 h, P<0.0001) and treatment (0, 10, 25, 50, and 75% nonviable sperm, P<0.0001) affected percent total sperm motility and percent viable sperm for both staining protocols. Actual percent viable sperm for each time and treatment did not differ from expected values. PMID:12935852

Love, C C; Thompson, J A; Brinsko, S P; Rigby, S L; Blanchard, T L; Lowry, V K; Varner, D D

2003-10-01

182

Design and synthesis of a squaraine dye for long wavelength fluorescence-based biosensors  

NASA Astrophysics Data System (ADS)

The design and synthesis of an environmentally sensitive long wavelength fluorescing squaraine dye for conjugation to proteins is dsecribed. Environmentally sensitive dyes are valuable for probing environmental changes that occur when labeled proteins bind their corresponding ligands and can be used to construct flyorescent sensors. Long wavelength (>650 nm) dyes would enable through-skin wireless sensing with minimum interference from the background. While several environmentally sensitive dyes are known in the visible spectrum, only a few are available in the long wavelength region, and none of them are available with reactive groups suitable for protein conjugation. Several derivatives of squarain dyes are known to be environmentally sensitive and fluorescent in the long wavelength region, but none of them are available with linkers for protein conjugation. In order to achieve this goal, we developed a synthetic scheme to introduce a reactive linker onto an anilinic squaraine that is highly sensitive to its environment. The synthesis involves the preparation of the dye with an iodoacetyl ester linker that readily reacts with a thiol on a cysteine residue of the binding protein. The squaraine dye was conjugated to known binding proteins that were evaluated as optical sensors. Ultimately, we expect these systems to measure analytes in the body and transmit information through the skin to an external monitor.

Pitner, J. Bruce; Thomas, K. Joseph; Sherman, Douglas B.; Alarcon, Javier; Mohiuddin, Ghulam; Kyler, Keith S.; Venepalli, Bhaskar R.

2005-04-01

183

Polymerase chain reaction for verification of fluorescent colonies of Erwinia chrysanthemi and Pseudomonas putida WCS358 in immunofluorescence colony staining.  

PubMed

The potential of polymerase chain reaction (PCR) for verifying the identity of colonies stained by the immunofluorescence colony-staining (IFC) procedure was investigated. Using primers directed against conserved sequences of the pectate lyase-genes coding for isozymes PLa, PLd and PLe of Erwinia chrysanthemi, the authors confirmed the identity of 96% of 20 fluorescent target colonies, punched from IFC-stained samples with pure cultures. In pour plates with mixtures of Erw. chrysanthemi and non-target colonies from potato peel extracts, the identity of 90% of 113 target colonies was confirmed. Using primers directed against sequences of the ferric-pseudobactin receptor gene pupA of Pseudomonas putida WCS358, the identity of 96% of 22 target colonies was confirmed in IFC-stained samples with pure cultures. In pour plates with mixtures of Ps. putida WCS358 and non-target bacteria from compost extracts, the identity of 59% of 108 fluorescent colonies was confirmed by PCR. It was shown that components from non-target bacteria lowered the threshold level of PCR for Ps. putida WCS358 100-fold. PMID:8567494

van der Wolf, J M; van Beckhoven, J R; de Vries, P M; Raaijmakers, J M; Bakker, P A; Bertheau, Y; van Vuurde, J W

1995-11-01

184

New epifluorescence microscope providing pairs of specific fluorescence images of double-stained cells for simultaneous visual perception and for quantification  

NASA Astrophysics Data System (ADS)

A new epi-fluorescence microscope for analysis of cells stained with two fluorochromes which can be spectrally isolated is described. The system makes it possible to perform independent and specific spectral selection of each dye (e.g. DAPI and CY3) while perceiving the two specific images simultaneously by eye. The optics uses splitting of the primary excitation and emission light beams, independent modification of the separated beams, and their reunification. Modifications in the separated beams comprise: (1) isolation of specific wavelengths (365 nm and 546 nm in the excitation light path, 435 - 500 nm and 590 - 750 nm in the emission light beams), (2) wavelength switching without image displacement and blur by means of a light chopper alternating between ultraviolet-excitation/blue-detection and green-excitation/red-detection at frequencies of up to 140 Hz for observation by eye without image flicker, and (3) the possible separate positioning of lenses for compensation of chromatic aberrations. The system demonstrates a good transmission of the chosen wavelengths. A high specificity of double fluorescence analysis with minimal effects of spectral overlap was attained with good temporal resolution. It has been shown that it is feasible to obtain separate chromatic compensations for the use of a microscope objective in spectral regions outside the range for which the objective is corrected. Quantitative and independent measurements of the two fluorescence images by a CCD camera synchronized with the light chopper are feasible. In conclusion, this imaging system is outlined for highly specific visual analysis and exact quantitative measurement of double fluorescence labeled specimens in cytology and histology.

Heiden, Thomas; Tribukait, Bernhard

1996-05-01

185

A method for evaluating the use of fluorescent dyes to track proliferation in cell lines by dye dilution.  

PubMed

Labeling nonquiescent cells with carboxyfluorescein succinimidyl ester (CFSE)-like dyes gives rise to a population width exceeding the threshold for resolving division peaks by flow cytometry. Width is a function of biological heterogeneity plus extrinsic and intrinsic error sources associated with the measurement process. Optimal cytometer performance minimizes extrinsic error, but reducing intrinsic error to the point of facilitating peak resolution requires careful fluorochrome selection and fluorescent cell sorting. In this study, we labeled the Jurkat and A549 cell lines with CFSE, CellTraceViolet (CTV), and eFluor 670 proliferation dye (EPD) to test if we could resolve division peaks in culture after reducing the labeled input widths by cell sorting. Reanalysis of the sorted populations to ascertain the level of reduction achieved always led to widths exceeding the gated limits due to the contribution of errors. Measuring detector-specific extrinsic error by sorting uniform fluorescent particles with similar spectral properties to the tracking dyes allowed us to determine the intrinsic error for each dye and cell type using a simple mathematical approach. We found that cell intrinsic error ultimately dictated whether we could resolve division peaks, and that as this increased, the required sort gate width to resolve any division peaks decreased to the point whereby issues with yield made A549 unsuitable for this approach. Finally, attempts to improve yields by setting two concurrent sort gates on the fluorescence distribution enriched for cells in different stages of the cell cycle that had nonequivalent proliferative properties in culture and thus should be practiced with caution. PMID:24166880

Begum, Julfa; Day, William; Henderson, Carl; Purewal, Sukhveer; Cerveira, Joana; Summers, Huw; Rees, Paul; Davies, Derek; Filby, Andrew

2013-12-01

186

Testing the Fraunhofer line discriminator by sensing fluorescent dye  

NASA Technical Reports Server (NTRS)

The experimental Fraunhofer Line Discriminator (FLD) has detected increments of Rhodamine WT dye as small as 1 ppb in 1/2 meter depths. It can be inferred that increments considerably smaller than 1 ppb will be detectable in depths considerably greater than 1/2 meter. Turbidity of the water drastically reduces luminescence or even completely blocks the transmission of detectable luminescence to the FLD. Attenuation of light within the water by turbidity and by the dye itself are the major factors to be considered in interpreting FLD records and in relating luminescence coefficient to dye concentration. An airborne test in an H-19 helicopter established feasibility of operating the FLD from the aircraft power supply, and established that the rotor blades do not visibly affect the monitoring of incident solar radiation.

Stoertz, G. E.

1969-01-01

187

Fluorescence switch of dye-infiltrated SiO2 inverse opal based on acid-base vapors or light  

NASA Astrophysics Data System (ADS)

The acid-base vapors/light double responsive dye-infiltrated SiO2 inverse opal photonic crystals (PCs) were fabricated by sacrificial template method and a subsequent infiltration of spiropyran derivative dye molecules. The fluorescence of ring-open dye molecules infiltrated in PCs can be switched on/off based on different fluorescence properties of spiropyran dye under stimuli of acid-base vapors or light, when PCs with suitable stopband were selected. The fluorescence switch behavior based on PCs has potential applications in data storage, color displays, chemical and biological sensors.

Zhang, Y. Q.; Wang, J. X.; Shang, Y. L.; Song, Y. L.; Jiang, L.

2011-03-01

188

The mutual influence of two different dyes on their sensitized fluorescence (cofluorescence) in nanoparticles from complexes  

NASA Astrophysics Data System (ADS)

We have studied the fluorescence sensitization and quenching for pairs of different dyes simultaneously incorporated into nanoparticles from complexes M(diketone)3phen, where M(III) is La(III), Lu(III), or Sc(III); diketone is p-phenylbenzoyltrifluoroacetone (PhBTA) or naphthoyltrifluoroacetone (NTA); and phen is 1,10-phenanthroline. We have shown that, upon formation of nanoparticles in the solution in the presence of two dyes the concentrations of which are either comparable with or lower than the concentration of nanoparticles (<20 nM), the intensities of the sensitized fluorescence of dyes in nanoparticles in binary solutions and in solutions of either of the dyes coincide. We have found that the intensity of sensitized fluorescence of small (<20 nM) concentrations of rhodamine 6G (R6G) or Nile blue (NB) increases by an order of magnitude upon simultaneous introduction into nanoparticles of 1 ?M of coumarin 30 (C30), while the intensity of fluorescence of C30 sensitized by complexes decreases by an order of magnitude. The same effect is observed as 1 ?M of R6G are introduced into nanoparticles with NB ([NB] ? 20 nM). The increase in the fluorescence of dye molecules upon their incorporation from the solution into nanoparticles from complexes is noticeably lower than that expected from the proposed ratio of concentrations of complexes and dyes in nanoparticles. Analysis of the obtained data indicates that the introduction of large concentrations of C30 or R6G dyes into nanoparticles makes it possible to prevent large energy losses due to impurities or upon transition to a triplet state that arises during the migration of the excitation energy over S 1 levels of complexes. Energy accumulated by these dyes is efficiently transferred to another dye that is present in the solution at lower concentrations and that has a lower-lying S 1 level, which makes it possible to increase its fluorescence by an order of magnitude upon its incorporation into nanoparticles.

Mironov, L. Yu.; Sveshnikova, E. B.; Ermolaev, V. L.

2013-10-01

189

Polarization and symmetry of electronic transitions in long fluorescence lifetime triangulenium dyes.  

PubMed

To fully exploit the capabilities of fluorescence probes in modern experiments, where advanced instrumentation is used to probe complex environments, other photophysical properties than emission color and emission intensity are monitored. Each dye property can be addressed individually as well as collectively to provide in-depth information unavailable from the standard intensity measurements. Dyes with long emission lifetimes and strongly polarized transitions enable the monitoring of lifetime changes as well as emission polarization (anisotropy). Thus experiments can be designed to follow slow dynamics. The UV and visible electronic transitions of a series of red-emitting dyes based on the triangulenium motif are investigated. We resolve overlapping features in the spectra and assign the orientation of the transition moments to the molecular axes. The result is the complete Jablonski diagram for the UV and visible spectral region. The symmetries of the studied dyes are shown to have a large influence on the optical response, and they are clearly separated into two groups of symmetry by their photophysical properties. The C(2v) symmetric dyes, azadioxatriangulenium (ADOTA(+)) and diazaoxatriangulenium (DAOTA(+)), have high emission anisotropies, fluorescence lifetimes around 20 ns, and fluorescence quantum yields of ?50%. The trioxatriangulenium (TOTA(+)) and triazatriangulenium (TATA(+)) dyes-nominally of D(3h) symmetry-have fluorescence lifetimes around 10 ns lifetimes and fluorescence quantum yields of 10-15%. However, the D(3h) symmetry is shown to be lowered to a point group, where the axes transform uniquely such that the degeneracy of the E' states is lifted. PMID:23391292

Thyrhaug, Erling; Sørensen, Thomas Just; Gryczynski, Ignacy; Gryczynski, Zygmunt; Laursen, Bo W

2013-03-14

190

Multifunctional Particles: Magnetic Nanocrystals and Gold Nanorods Coated with Fluorescent Dye-Doped Silica Shells  

PubMed Central

Multifunctional colloidal core-shell nanoparticles of magnetic nanocrystals (of iron oxide or FePt) or gold nanorods encapsulated in silica shells doped with the fluorescent dye, Tris(2,2?-bipyridyl)dichlororuthenium(II) hexahydrate (Rubpy) were synthesized. The as-prepared magnetic nanocrystals are initially hydrophobic and were coated with silica using a microemulsion approach, while the as-prepared gold nanorods are hydrophilic and were coated with silica using a Stöber-type of process. Each approach yielded monodisperse nanoparticles with uniform fluorescent dye-doped silica shells. These colloidal heterostructures have the potential to be used as dual-purpose tags—exhibiting a fluorescent signal that could be combined with either dark-field optical contrast (in the case of the gold nanorods), or enhanced contrast in magnetic resonance images (in the case of magnetic nanocrystal cores). The optical and magnetic properties of the fluorescent silica-coated gold nanorods and magnetic nanocrystals are reported.

Heitsch, Andrew T.; Smith, Danielle K.; Patel, Reken E.; Ress, David; Korgel, Brian A.

2008-01-01

191

Testing the Fraunhofer Line Discriminator by Sensing Fluorescent Dye.  

National Technical Information Service (NTIS)

The experimental Fraunhofer Line Discriminator (FLD) has detected increments of Rhodamine WT dye as small as 1 ppb in 12 meter depths. It can be inferred that increments considerably smaller than 1 ppb will be detectable in depths considerably greater tha...

G. E. Stoertz

1969-01-01

192

Fluorescence energy transfer in quantum dot/azo dye complexes in polymer track membranes  

PubMed Central

Fluorescence resonance energy transfer in complexes of semiconductor CdSe/ZnS quantum dots with molecules of heterocyclic azo dyes, 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo) resorcinol, formed at high quantum dot concentration in the polymer pore track membranes were studied by steady-state and transient PL spectroscopy. The effect of interaction between the complexes and free quantum dots on the efficiency of the fluorescence energy transfer and quantum dot luminescence quenching was found and discussed.

2013-01-01

193

Deposition of Contaminated Sediments in Boston Harbor Studied Using Fluorescent Dye and Particle Tracers  

NASA Astrophysics Data System (ADS)

The residence time of water and suspended particles in Fort Point Channel, a sub-region of Boston Harbor containing a major combined sewer overflow and highly contaminated sediment, was determined during three field surveys by measuring the disappearance of fluorescent tracers from the water column. Flushing by advective movement was quantified using Rhodamine WT dye, a dissolved tracer which has negligible interaction with suspended sediment. The fate of suspended particles was inferred from measured concentrations of fluorescent pigment particles which were initially well mixed with Rhodamine dye and which have a size range and settling velocity comparable to the sewage particles of interest. Dye and particle concentrations were measured by fluorescent spectroscopy of water samples obtained throughout the channel over a week following tracer introduction. Dye measurements indicate that channel water is replaced on a scale of 1-2·7 days, depending on tidal amplitude and phase during tracer release, and the magnitude of freshwater inflow. Ratios of normalized particle concentration to dye concentration suggest effective deposition velocities of 1·5-3·3 m day -1; this is an order of magnitude faster than observed in laboratory settling columns suggesting that removal of suspended tracer particles from Fort Point Channel during our surveys may have been the result of scavenging by a bottom ' fluff ' layer. This finding is consistent with our previous observation of particle deposition in Salem Sound, Massachusetts, U.S.A. and in controlled laboratory studies of particle aggregation at the sediment-water interface.

Adams, E. E.; Stolzenbach, K. D.; Lee, J.-J.; Caroli, J.; Funk, D.

1998-03-01

194

Collective fluorescence switching of counterion-assembled dyes in polymer nanoparticles.  

PubMed

The current challenge in the field of fluorescent nanoparticles (NPs) for bioimaging is to achieve extreme brightness and external control of their emission using biodegradable materials. Here we propose a new concept of fluorescent polymer NPs, doped with ionic liquid-like salts of a cationic dye (octadecyl rhodamine B) with a bulky hydrophobic counterion (fluorinated tetraphenylborate) that serves as spacer minimizing dye aggregation and self-quenching. The obtained 40-nm poly(D,L-lactide-co-glycolide) NPs containing up to 500 dyes are brighter than quantum dots and exhibit photo-induced reversible on/off fluorescence switching, never reported for dye-doped NPs. We show that this collective switching of hundreds of dyes is due to ultrafast excitation energy transfer and can be used for super-resolution imaging. These NPs, being spontaneously endocytosed by living cells, feature high signal-to-noise ratio and absence of toxicity. The counterion-based concept opens the way to a new class of nanomaterials for sensing, imaging and light harvesting. PMID:24909912

Reisch, Andreas; Didier, Pascal; Richert, Ludovic; Oncul, Sule; Arntz, Youri; Mély, Yves; Klymchenko, Andrey S

2014-01-01

195

Interaction of gold nanoclusters with IR light emitting cyanine dyes: a systematic fluorescence quenching study.  

PubMed

This paper describes the intermolecular interactions of gold nanoclusters (Au NCs) with cyanine dyes, namely HITC P, DTTC I, and IR 144. All the cyanine dyes quenched the fluorescence of Au NCs effectively. Steady-state and time-resolved measurements were performed to understand the competition between electron transfer and energy transfer in the Au NCs and cyanine dye system. A significant spectral overlap between the emission spectrum of the Au NCs and the absorption spectrum of cyanine dyes was observed, making both ideal for studying FRET interactions. However, after careful inspection of the steady state spectra and time resolved decays we concluded that photoinduced electron transfer (PET) could be the major pathway to quench the fluorescence intensity of Au NCs. To elucidate the interaction mechanism between Au NCs and cyanine dyes, docking studies were also performed. The docking studies reveal that the quencher molecules, i.e. cyanine dyes, come in close proximity with the 34-cysteine (Cys) in BSA where the Au clusters are located to enable the electron transfer process. PMID:25018085

Banerjee, Chiranjib; Kuchlyan, Jagannath; Banik, Debasis; Kundu, Niloy; Roy, Arpita; Ghosh, Surajit; Sarkar, Nilmoni

2014-08-28

196

Multiple labeling of antibodies with dye/DNA conjugate for sensitivity improvement in fluorescence immunoassay.  

PubMed

Fluorescence immunoassays are widely used in life science research, medical diagnostics, and environmental monitoring due to the intrinsically high specificity, simplicity, and versatility of immunoassays, as well as the availability of a large variety of fluorescent labeling molecules. However, the sensitivity needs to be improved to meet the ever-increasing demand in the new proteomics era. Here, we report a simple method of attaching multiple fluorescent labels on an antibody with a dye/DNA conjugate to increase the immunoassay sensitivity. In the work, mouse IgG adsorbed on the surface of a 96-well plate was detected by its immunoreaction with biotinylated goat anti-mouse antibody. A 30 base pair double-stranded oligonucleotide terminated with biotin was attached to the antibody through the biotin/streptavidin/biotin interaction. Multiple labeling of the antibody was achieved after a fluorescent DNA probe was added into the solution and bound to the oligonucleotide at high ratios. By comparison with fluorescein-labeled streptavidin, the assay with the dye/DNA label produced up to 10-fold increase in fluorescence intensity, and consequently about 10-fold lower detection limit. The multiple labeling method uses readily available reagents, and is simple to implement. Further sensitivity improvement can be obtained by using longer DNAs for antibody labeling, which can incorporate more fluorescent dyes on each DNA. PMID:17685565

Zhang, Qin; Guo, Liang-Hong

2007-01-01

197

Optimization of oxygen sensitive optical dye membrane polymers for fluorescent-lifetime-based physiological biosensing  

Microsoft Academic Search

Fiber optic based sensor technologies have many significant advantages over electrochemical sensors, and as a result have broad application for sensing in biology, agriculture and medicine. An important component of fiber optic biosensor is the sensing element. Usually, a polymer matrix containing the analyte specific fluorescent dye is immobilized on one end of the fiber optic probe. The polymer matrix

M. R. Chatni; D. E. Maier; D. M. Porterfield

2007-01-01

198

Fluorescent Dye May Help Spot Date-Rape Drug in Drinks  

MedlinePLUS

... enable JavaScript. Fluorescent Dye May Help Spot Date-Rape Drug in Drinks Researchers say chemical changes color ... 31, 2014 Related MedlinePlus Pages Alcohol Club Drugs Sexual Assault MONDAY, March 31, 2014 (HealthDay News) -- Researchers say ...

199

Safe susceptibility testing of Mycobacterium tuberculosis by flow cytometry with the fluorescent nucleic acid stain SYTO 16.  

PubMed

The time needed to obtain susceptibility results of Mycobacterium tuberculosis using classical methodologies is still too long, and flow cytometry is a promising technique in the setting of the clinical laboratory, giving fast results. A safe, reliable and rapid method to study susceptibility to streptomycin, isoniazide, rifampicin and ethambutol is described. Isolates of mycobacteria, grown for 72 h in the absence or presence of antimycobacterial drugs in the mycobacteria growth indicator tube (MGIT), were heat-killed, stained with SYTO 16 (a nucleic acid fluorescent stain that only penetrates cells with severe lesion of the membrane) and then analysed by flow cytometry. Sixteen strains with different susceptibility patterns were tested and an excellent correlation with the BACTEC MGIT 960 protocol for susceptibility was shown. In contrast to resistant strains, sensitive strains lose their cellular integrity after incubation with antimycobacterial drugs, allowing SYTO 16 to penetrate the cells. Comparing the intensity of fluorescence of Mycobacterium cells incubated with antimycobacterial drugs with that of drug-free cells, after staining with SYTO 16, it was possible to distinguish between sensitive, intermediate and resistant phenotypes. Other cytometric assays have been described for mycobacteria susceptibility testing but these have lower accuracy and safety. The described flow cytometric assay is a simple, fast, safe and accurate way to determine susceptibility of M. tuberculosis. PMID:15591259

Pina-Vaz, C; Costa-de-Oliveira, S; Rodrigues, A G

2005-01-01

200

Time-resolved fluorescence studies of dye-polymers as excited by laser and beta-radiation  

Microsoft Academic Search

The fluorescence properties and energy transfer processes of dye-polymers have been investigated with time-resolved fluorescence spectroscopy. Based on an understanding of these characteristics, the new dye-polymers were optimized for potential applications in scintillators and wavelength shifters used in high energy particle detection. The two primary criteria for suitable samples were high quantum efficiencies and short fluorescence decay times. In this

Lin-I. Liu

1997-01-01

201

Development of Thermally Stable and Highly Fluorescent IR Dyes  

NASA Technical Reports Server (NTRS)

Fluorophores are the core component in various optical applications such as sensors and probes. Fluorphores with low-energy or long wavelength emission, in particular, in NIR region, possess advantages of low interference and high sensitivity. In this study, we has explored several classes of imidazole-based compounds for NIR fluorescent properties and concluded: (1) thiazole-based imidazole compounds are fluorescent; (2) emission energy is tunable by additional donor groups; (3) they also possess impressive two- photon absorption properties; and (4) fluorescence emission can be induced by two- photon input. This report summarizes (1) synthesis of new series of fluorophore; (2) impact of electron-withdrawing groups on fluorescent property; (3) unique property of two-photon absorption; and (4) on-going development.

Bu, Xiu R.

2004-01-01

202

Multifunctional particles: Magnetic nanocrystals and gold nanorods coated with fluorescent dye-doped silica shells  

SciTech Connect

Multifunctional colloidal core-shell nanoparticles of magnetic nanocrystals (of iron oxide or FePt) or gold nanorods encapsulated in silica shells doped with the fluorescent dye, Tris(2,2'-bipyridyl)dichlororuthenium(II) hexahydrate (Rubpy) were synthesized. The as-prepared magnetic nanocrystals are initially hydrophobic and were coated with silica using a microemulsion approach, while the as-prepared gold nanorods are hydrophilic and were coated with silica using a Stoeber type of process. Each approach yielded monodisperse nanoparticles with uniform fluorescent dye-doped silica shells. These colloidal heterostructures have the potential to be used as dual-purpose tags-exhibiting a fluorescent signal that could be combined with either dark-field optical contrast (in the case of the gold nanorods), or enhanced contrast in magnetic resonance images (in the case of magnetic nanocrystal cores). The optical and magnetic properties of the fluorescent silica-coated gold nanorods and magnetic nanocrystals are reported. - Graphical abstract: Colloidal gold nanorods and iron platinum and iron oxide nanocrystals were encapsulated with fluorescent dye-doped silica shells using a generic coating strategy. These heterostructures are promising contrast agents for dual-mode medical imaging. Their optical and magnetic properties were studied and are reported here.

Heitsch, Andrew T.; Smith, Danielle K.; Patel, Reken N. [Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, University of Texas at Austin, Austin, TX 78712-1062 (United States); Ress, David [Imaging Research Center, University of Texas at Austin, Austin, TX 78759-5316 (United States); Korgel, Brian A. [Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, University of Texas at Austin, Austin, TX 78712-1062 (United States)], E-mail: korgel@che.utexas.edu

2008-07-15

203

Synchronous fluorescence spectroscopic study of solvatochromic curcumin dye  

NASA Astrophysics Data System (ADS)

Curcumin, the main yellow bioactive component of turmeric, has recently acquired attention by chemists due its wide range of potential biological applications as an antioxidant, an anti-inflammatory, and an anti-carcinogenic agent. This molecule fluoresces weakly and poorly soluble in water. In this detailed study of curcumin in thirteen different solvents, both the absorption and fluorescence spectra of curcumin was found to be broad, however, a narrower and simple synchronous fluorescence spectrum of curcumin was obtained at ? ? = 10-20 nm. Lippert-Mataga plot of curcumin in different solvents illustrated two sets of linearity which is consistent with the plot of Stokes' shift vs. the ET30. When Stokes's shift in wavenumber scale was replaced by synchronous fluorescence maximum in nanometer scale, the solvent polarity dependency measured by ?SFSmax vs. Lippert-Mataga plot or ET30 values offered similar trends as measured via Stokes' shift for protic and aprotic solvents for curcumin. Better linear correlation of ?SFSmax vs. ?* scale of solvent polarity was found compared to ?absmax or ?emmax or Stokes' shift measurements. In Stokes' shift measurement both absorption/excitation as well as emission (fluorescence) spectra are required to compute the Stokes' shift in wavenumber scale, but measurement could be done in a very fast and simple way by taking a single scan of SFS avoiding calculation and obtain information about polarity of the solvent. Curcumin decay properties in all the solvents could be fitted well to a double-exponential decay function.

Patra, Digambara; Barakat, Christelle

2011-09-01

204

New fluoranthene FLUN-550 as a fluorescent probe for selective staining and quantification of intracellular lipid droplets.  

PubMed

A new class of live cell permeant, nontoxic fluoranthene-based fluorescent probe (FLUN-550) having a high Stokes shift in aqueous medium has been discovered. It showed selective staining of lipid droplets (LDs, dynamic cytoplasmic organelles) at a low concentration without background noise in in vitro live cell imaging of 3T3-L1 preadipocytes, J774 macrophages, MCF7 breast cancer cells, and single-celled, parasitic protozoa Leishmania donovani promastigotes and in vivo nonparasitic soil nematode C. elegans. PMID:24410145

Goel, Atul; Sharma, Ashutosh; Kathuria, Manoj; Bhattacharjee, Arindam; Verma, Ashwni; Mishra, Prabhat R; Nazir, Aamir; Mitra, Kalyan

2014-02-01

205

Plasmonic properties and enhanced fluorescence of gold and dye-doped silica nanoparticle aggregates  

NASA Astrophysics Data System (ADS)

The development of metal-enhanced fluorescence has prompted a great interest in augmenting the photophysical properties of fluorescent molecules with noble metal nanostructures. Our research efforts, outlined in this dissertation, focus on augmenting properties of fluorophores by conjugation with gold nanostructures. The project goals are split into two separate efforts; the enhancement in brightness of fluorophores and long distance non-radiative energy transfer between fluorophores. We believe that interacting dye-doped silica nanoparticles with gold nanoparticles can facilitate both of these phenomena. Our primary research interest is focused on optimizing brightness, as this goal should open a path to studying the second goal of non-radiative energy transfer. The two major challenges to this are constructing suitable nanomaterials and functionalizing them to promote plasmonically active complexes. The synthesis of dye-doped layered silica nanoparticles allows for control over the discrete location of the dye and a substrate that can be surface functionalized. Controlling the exact location of the dye is important to create a silica spacer, which promotes productive interactions with metal nanostructures. Furthermore, the synthesis of silica nanoparticles allows for various fluorophores to be studied in similar environments (removing solvent and other chemo-sensitive issues). Functionalizing the surface of silica nanoparticles allows control over the degree of silica and gold nanoparticle aggregation in solution. Heteroaggregation in solution is useful for producing well-aggregated clusters of many gold around a single silica nanoparticle. The dye-doped surface functionalized silica nanoparticles can than be mixed efficiently with gold nanomaterials. Aggregating multiple gold nanospheres around a single dye-doped silica nanoparticle can dramatically increase the fluorescent brightness of the sample via metal-enhanced fluorescence due to increase plasmonic scattering. Our aim is to promote heteroaggregation with functionalized silica nanoparticles while minimizing homoaggregation of silica-silica or gold-gold species. Reproducible production of multiple gold nanospheres about a dye-doped silica nanoparticle should lead to dramatic fluorescence brightness enhancements in solution. Gold nanorods can potentially be used to establish radiationless energy transfer between hetero dye-doped silica nanoparticles via gold nanorod plasmon mediated FRET by aggregating two different dye-doped silica nanoparticles preferentially at opposite ends of the nanorod. End-cap binding is accomplished by tuning the strength of gold binding ligands that functionalize the surface of the silica nanoparticles. The gold nanorod can then theoretically serve as a waveguide by employing the longitudinal plasmon as a non-radiative energy transfer agent between the two different fluorophores, giving rise to a new ultrafast signaling paradigm. Heteroaggregation of dye-doped silica nanoparticles and gold nanorods can be potentially employed to as nano waveguides. Construction and aggregation of functionalized silica and gold nano-materials provides an opportunity to advance the field of fluorescence. The synthesis of gold nano-particles allows control over their size and shape, which give rise to useful optical and electronic properties. Silica nanoparticles provide a framework allowing control over a requisite distance for increasing beneficial and deceasing non-radiative dye-metal interactions as well fluorophore protection. Our aim is to take advantage of fine-tuned synthetic control of functionalized nanomaterials to realize the great potential of solution based metal-enhanced fluorescence for future applications.

Green, Nathaniel Scott

206

Detection of Bordetella pertussis in a clinical laboratory by culture, polymerase chain reaction, and direct fluorescent antibody staining; accuracy, and cost  

Microsoft Academic Search

Control of Bordetella pertussis in the community is hampered by slow and insensitive diagnostic tests. We therefore examined the accuracy and cost of culture, direct fluorescent antibody (DFA) staining, and PCR in a routine clinical laboratory. Six hundred thirty seven nasopharyngeal swabs and aspirates in casamino acids transport medium were cultured, stained with polyclonal (Difco), and monoclonal (BL-5 and Accu–Mab)

Peter A. G Tilley; M. V Kanchana; Ineke Knight; Joseph Blondeau; Nick Antonishyn; Harry Deneer

2000-01-01

207

A new polymerizable fluorescent PET chemosensor of fluoride (F-) based on naphthalimide-thiourea dye  

NASA Astrophysics Data System (ADS)

A novel N-allyl-4-amino-substituted 1,8-naphthalimide dye, containing thiourea functional group with intense yellow-green fluorescence was successfully synthesized. Copolymerization was done with styrene. The photophysical characteristics of dye and its copolymer in solution and solid film were investigated in the presence of halide ions. The results reveal that the fluorescence emissions of the monomer dye and also its polymer were 'switched off' in the presence of fluoride ions. The dye showed spectral shifts and intensity changes in the presence of more fluoride ions which lead to detect certain fluoride concentrations of 10-150 mM at visible wavelengths. By adding the fluoride ions, green-yellow to purple color changes occurs and the green fluorescence emission quenches, all of which easily observed by naked eyes. These phenomena are essential for producing a dual responsive chemosensor for fluoride ions. The polymeric sensor, in the film state exhibited a fast response to the fluoride ions.

Alaei, Parvaneh; Rouhani, Shohre; Gharanjig, Kamaladin; Ghasemi, Jahanbakhsh

2012-05-01

208

A new polymerizable fluorescent PET chemosensor of fluoride (F-) based on naphthalimide-thiourea dye.  

PubMed

A novel N-allyl-4-amino-substituted 1,8-naphthalimide dye, containing thiourea functional group with intense yellow-green fluorescence was successfully synthesized. Copolymerization was done with styrene. The photophysical characteristics of dye and its copolymer in solution and solid film were investigated in the presence of halide ions. The results reveal that the fluorescence emissions of the monomer dye and also its polymer were 'switched off' in the presence of fluoride ions. The dye showed spectral shifts and intensity changes in the presence of more fluoride ions which lead to detect certain fluoride concentrations of 10-150 mM at visible wavelengths. By adding the fluoride ions, green-yellow to purple color changes occurs and the green fluorescence emission quenches, all of which easily observed by naked eyes. These phenomena are essential for producing a dual responsive chemosensor for fluoride ions. The polymeric sensor, in the film state exhibited a fast response to the fluoride ions. PMID:22321515

Alaei, Parvaneh; Rouhani, Shohre; Gharanjig, Kamaladin; Ghasemi, Jahanbakhsh

2012-05-01

209

Fluorescence staining of yeast cells permeabilized by killer toxin K1: Determination of optimum conditions  

Microsoft Academic Search

Optimal assay conditions were established for the previously described method used to determine the activity ofSaccharomyces cerevisiae pore-forming killer toxin K1. The method is based on cell staining with bromocresol purple. Sensitive cells ofS. cerevisiae from the early exponential phase under nongrowth conditions and in the presence of glucose were the most convenient for determining the killer toxin activity. Maximum

Helena Kurzweilová; Karel Sigler

1993-01-01

210

Electrochromism and Solvatochromism in Fluorescence Response of Organic Dyes: A Nanoscopic View  

Microsoft Academic Search

\\u000a \\u000a Abstract  Methods are described that allow prediction and understanding of solvatochromism and fluorescence quenching of dyes embedded\\u000a in a nanometer-scale medium, e.g., solvent, protein, and membranes. Spectra of the dye are calculated at the microscopic level\\u000a using quantum mechanics coupled to the point charges representing the medium by Coulombic potentials, while the whole system\\u000a propagates by classical molecular mechanics. This view

Patrik R. Callis

211

Phosphine-Quenching of Cyanine Dyes as a Versatile Tool for Fluorescence Microscopy  

PubMed Central

We report that the cyanine dye Cy5 and several of its structural relatives are reversibly quenched by the phosphine TCEP (tris(2-carboxyethyl)phosphine). Using Cy5 as a model, we show that the quenching reaction occurs by 1,4-addition of the phosphine to the polymethine bridge of Cy5 to form a covalent adduct. Illumination with ultraviolet light dissociates the adduct and returns the dye to the fluorescent state. We demonstrate that TCEP quenching can be used for superresolution imaging as well as for other applications, such as differentiating between molecules inside and outside the cell.

Vaughan, Joshua C.; Dempsey, Graham T.; Sun, Eileen; Zhuang, Xiaowei

2013-01-01

212

Using Fluorescent Dyes to Demonstrate Solution-Mixing Techniques.  

ERIC Educational Resources Information Center

Describes a demonstration using a variety of clear solutions in which the instructor asks students whether the solutions appear homogeneous or inadequately mixed. The solutions are then induced to fluoresce with ultraviolet light to provide visible evidence of homogeneity or nonhomogeneity. (PR)

Shmaefsky, Brian; Shmaefsky, Mary Jo

1994-01-01

213

Quantum dots versus organic dyes as fluorescent labels  

Microsoft Academic Search

Suitable labels are at the core of luminescence and fluorescence imaging and sensing. One of the most exciting, yet also controversial, advances in label technology is the emerging development of quantum dots (QDs)—inorganic nanocrystals with unique optical and chemical properties but complicated surface chemistry—as in vitro and in vivo fluorophores. Here we compare and evaluate the differences in physicochemical properties

Markus Grabolle; Sara Cavaliere-Jaricot; Roland Nitschke; Ute Resch-Genger; Thomas Nann

2008-01-01

214

Benchtop Antigen Detection Technique using Nanofiltration and Fluorescent Dyes  

NASA Technical Reports Server (NTRS)

The designed benchtop technique is primed to detect bacteria and viruses from antigenic surface marker proteins in solutions, initially water. This inclusive bio-immunoassay uniquely combines nanofiltration and near infrared (NIR) dyes conjugated to antibodies to isolate and distinguish microbial antigens, using laser excitation and spectrometric analysis. The project goals include detecting microorganisms aboard the International Space Station, space shuttle, Crew Exploration Vehicle (CEV), and human habitats on future Moon and Mars missions, ensuring astronaut safety. The technique is intended to improve and advance water contamination testing both commercially and environmentally as well. Lastly, this streamlined technique poses to greatly simplify and expedite testing of pathogens in complex matrices, such as blood, in hospital and laboratory clinics.

Scardelletti, Maximilian C.; Varaljay, Vanessa

2009-01-01

215

Local viscosity analysis of triblock copolymer micelle with cyanine dyes as a fluorescent probe.  

PubMed

The local viscosity of Pluronic F127 triblock copolymer micelles in water was determined with cyanine dyes as fluorescent probes. These dyes show very weak fluorescence at a low temperature, but show enhanced fluorescence at a temperature higher than the critical micellization temperature (T(cm)). This is because a viscous environment within the micelle suppresses the formation of a nonradiative twisted intramolecular charge transfer (TICT) excited state of the dyes. The good correlation between the fluorescence quantum yields of the dyes and the viscosity and the temperature of the media allows a determination of local viscosity of micelle based on the fluorescence quantum yields. The local viscosity of both core and corona regions of micelles increases at >T(cm) and shows a maximum at a temperature 7-9 °C higher than T(cm), and decreases at higher temperature due to the increased fluidity. The core viscosity is larger than that of the corona, and the corona viscosity increases toward the micelle center. The polymer concentration has different effects on the core and corona viscosity: the corona viscosity increases with a polymer concentration increase at the entire temperature range, whereas the core viscosity increases only at a low temperature. The corona viscosity increase is due to the condensation of a large number of polyethylene oxide (PEO) blocks. In contrast, the dehydration degree of polypropylene oxide (PPO) blocks in the core scarcely changes, and the core has a similar composition regardless of polymer concentration. The larger polymer concentration promotes a micelle formation at lower temperature where the fluidity increase is very weak, resulting in larger core viscosity. PMID:20942435

Shiraishi, Yasuhiro; Inoue, Takuya; Hirai, Takayuki

2010-11-16

216

A Combined Immunofluorescence-DNA-Fluorescence Staining Technique for Enumeration of Thiobacillus ferrooxidans in a Population of Acidophilic Bacteria  

PubMed Central

An antiserum raised against whole cells of Thiobacillus ferrooxidans was allowed to react with a variety of acidophilic and nonacidophilic bacteria in an enzyme-linked immunosorbent assay and an indirect immunofluorescence assay. Both experiments demonstrated that the antiserum was specific at the species level. This preparation was used to evaluate the role of T. ferrooxidans in the microbial desulfurization process. Leaching experiments were performed, and the numbers of T. ferrooxidans cells and other bacteria were estimated by using a combined immunofluorescence-DNA-fluorescence staining technique that was adapted for this purpose. Nonsterile coal samples inoculated with T. ferrooxidans yielded high concentrations of soluble iron after 16 days. After this period, however, T. ferrooxidans cells could no longer be detected by the immunofluorescence assay, whereas the DNA-fluorescence staining procedure demonstrated a large number of microorganisms on the coal particles. These results indicate that T. ferrooxidans is removed by competition with different acidophilic microorganisms that were originally present on the coal. Images

Muyzer, Gerard; de Bruyn, Anke C.; Schmedding, Diederik J. M.; Bos, Piet; Westbroek, Peter; Kuenen, Gijs J.

1987-01-01

217

Visualization of cell death in mice with focal cerebral ischemia using fluorescent annexin A5, propidium iodide, and TUNEL staining.  

PubMed

To monitor stroke-induced brain damage and assess neuroprotective therapies, specific imaging of cell death after cerebral ischemia in a noninvasive manner is highly desirable. Annexin A5 has been suggested as a marker for imaging cell death under various disease conditions including stroke. In this study, C57BL6/N mice received middle cerebral artery occlusion (MCAO) and were injected intravenously with either active or inactive Cy5.5-annexin A5 48 hours after reperfusion. Some mice also received propidium iodide (PI), a cell integrity marker. Only in mice receiving active Cy5.5-annexin A5 were fluorescence intensities significantly higher over the hemisphere ipsilateral to MCAO than on the contralateral side. This was detected noninvasively and ex vivo 4 and 8 hours after injection. The majority of cells positive for fluorescent annexin A5 were also positive for PI and fragmented DNA as detected by terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL) staining. This study demonstrates the high specificity of annexin A5 for visualization of cell death in a mouse model of stroke. To our knowledge, this is the first study to compare the distribution of injected active and inactive annexin A5, PI, and TUNEL staining. It provides important information on the experimental and potential clinical applications of annexin A5-based imaging agents in stroke. PMID:21245871

Bahmani, Peyman; Schellenberger, Eyk; Klohs, Jan; Steinbrink, Jens; Cordell, Ryan; Zille, Marietta; Müller, Jochen; Harhausen, Denise; Hofstra, Leo; Reutelingsperger, Chris; Farr, Tracy Deanne; Dirnagl, Ulrich; Wunder, Andreas

2011-05-01

218

Sentinel lymph nodes detection with an imaging system using Patent Blue V dye as fluorescent tracer  

NASA Astrophysics Data System (ADS)

Sentinel lymph node biopsy is the gold standard to detect metastatic invasion from primary breast cancer. This method can help patients avoid full axillary chain dissection, thereby decreasing the risk of morbidity. We propose an alternative to the traditional isotopic method, to detect and map the sentinel lymph nodes. Indeed, Patent Blue V is the most widely used dye in clinical routine for the visual detection of sentinel lymph nodes. A Recent study has shown the possibility of increasing the fluorescence quantum yield of Patent Blue V, when it is bound to human serum albumin. In this study we present a preclinical fluorescence imaging system to detect sentinel lymph nodes labeled with this fluorescent tracer. The setup is composed of a black and white CCD camera and two laser sources. One excitation source with a laser emitting at 635 nm and a second laser at 785 nm to illuminate the region of interest. The prototype is operated via a laptop. Preliminary experiments permitted to determine the device sensitivity in the ?mol.L-1 range as regards the detection of PBV fluorescence signals. We also present a preclinical evaluation performed on Lewis rats, during which the fluorescence imaging setup detected the accumulation and fixation of the fluorescent dye on different nodes through the skin.

Tellier, F.; Steibel, J.; Chabrier, R.; Rodier, J. F.; Pourroy, G.; Poulet, P.

2013-03-01

219

Incorporating fluorescent dyes and quantum dots into magnetic microbeads for immunoassays.  

PubMed

Microbeads that are both paramagnetic and fluorescently labeled are commercially available in colors spanning the visible spectrum. Although these commercial beads can be bright, polydispersity in both size and fluorescent intensity limit their use in quantitative assays. Very recently, more monodisperse beads have become available, but their large size and surface properties make them less than ideal for some bioassay applications. Here we describe methods to customize commercial nonfluorescent magnetic microparticles with fluorescent dyes and quantum dots (QDs) without affecting their magnetic or surface chemical properties. Fluorescent dyes and 3.3-nm diameter CdSe/ZnS QDs were sequestered within 0.8-micron diameter magnetic beads by swelling the polystyrene matrix of the bead in organic solvent, letting the chromophores partition, and then collapsing the matrix in polar solvents. Chromophore incorporation has been characterized using both UV-visible absorption spectroscopy and fluorescence microscopy, with an average of 3 x 10(8) rhodamine 6G molecules/bead and 6 x 10(4) QDs/bead. The modified beads are uniform in size and intensity, with optical properties comparable to currently available commercial beads. Immunoassay results obtained with our custom fluorescent magnetic microbeads are consistent with those obtained using conventional magnetic microbeads. PMID:15088378

Mulvaney, Shawn P; Mattoussi, Heidi M; Whitman, Lloyd J

2004-04-01

220

Methods for Detecting Internalized, FM 1-43 Stained Particles in Epithelial Cells and Monolayers  

Microsoft Academic Search

The membrane dye FM 1-43 has frequently been used to quantify exocytosis in neurons. In epithelia, intense lateral intracellular space staining and fluctuations in baseline labeling produced inconsistent results. Membrane retrieved in the presence of FM 1-43 retains the dye, however, and cells that undergo compensatory endocytosis during and following evoked exocytosis contain punctate, fluorescent particles after washout of external

C. A. Bertrand; C. Laboisse; U. Hopfer; R. J. Bridges; R. A. Frizzell

2006-01-01

221

An artery-specific fluorescent dye for studying neurovascular coupling  

PubMed Central

We demonstrate that Alexa Fluor 633 hydrazide (Alexa Fluor 633) selectively labels neocortical arteries and arterioles by binding to elastin fibers. We measured sensory stimulus–evoked arteriole dilation dynamics in mouse, rat and cat visual cortex using Alexa Fluor 633 together with neuronal activity using calcium indicators or blood flow using fluorescein dextran. Arteriole dilation decreased fluorescence recorded from immediately underlying neurons, representing a potential artifact during neuronal functional imaging experiments.

Shen, Zhiming; Lu, Zhongyang; Chhatbar, Pratik Y; O'Herron, Philip; Kara, Prakash

2012-01-01

222

Rapid quantification of polyhydroxyalkanoates (PHA) concentration in activated sludge with the fluorescent dye Nile blue A.  

PubMed

The present study was conducted (1) to develop a rapid quantification method of polyhydroxyalkanoates (PHA) concentration in activated sludge by Nile blue A staining and fluorescence measurement and (2) to perform on-line monitoring of PHA concentrations in activated sludge. Activated sludge samples collected from laboratory scale sequencing batch reactors and full-scale wastewater treatment plants were stained with Nile blue A and their fluorescence intensities were determined. There was a high correlation (R2 > 0.97) between the fluorescence intensities of Nile blue A and PHA concentrations in activated sludge determined by gas chromatography. The Nile blue A staining and fluorescence measurement method allows us to determine PHA concentrations in activated sludge within only five minutes and up to 96 samples can be measured at once by using microplate reader. On-line monitoring of PHA concentrations in activated sludge was achieved by using a fluorometer equipped with a flow cell and the time point at which PHA concentration in activated sludge reached the maximum level could be identified. In addition, we examined the influence of pH, floc size and co-existing chemicals in activated sludge suspension on the fluorescence intensities of Nile blue A. PMID:22097056

Oshiki, M; Satoh, H; Mino, T

2011-01-01

223

Immuno-fluorescence staining patterns of leukocyte subsets in the skin of taurine and indicine cattle.  

PubMed

The immuno-staining patterns of skin leukocytes were investigated in three breeds of cattle: Holstein-Friesian, Brahman and Santa Gertrudis of similar age before and after tick infestation. The antibodies specific for CD45 and CD45RO reacted with cells in the skin of all Holstein-Friesian cattle but did not react with cells in the skin of any Brahman cattle. The same antibodies reacted with cells from the skin of four (CD45) and seven (CD45RO) of twelve Santa Gertrudis cattle. The antibodies specific for T cells and ?? subset of T cells recognized cells from all three breeds of cattle. The antibody specific for MHC class II molecules labelled cells of mostly irregular shape, presumably dermal dendritic cells and/or macrophages and Langerhans cells. The antibody specific for granulocytes (mAb CH138) reacted with cells only in sections cut from skin with lesions. The antibody specific for CD25(+) cells labelled regularly shaped cells that showed a wide range of intensities of staining. PMID:24011596

Constantinoiu, C C; Jonsson, N N; Jorgensen, W K; Jackson, L A; Piper, E K; Lew-Tabor, A E

2013-12-01

224

Fluorescent dyes as a probe for the localized field of coupled surface plasmon-related resonances  

SciTech Connect

The fluorescence light of Cy5 dye molecules in the vicinity of a metal grating is studied for varying directions of both the exciting and the emitted light. A different angular dependence of the intensity of the emitted light is observed for different directions of excitation. Model calculations that take into account the localization of the electrical field of grating-coupled surface plasmon-related resonances are in good agreement with the experimental observations. In addition, the spatially inhomogenous photobleaching of the dye in the field of the coupled resonances is experimentally observed. These results can be viewed both as a way to use chromophores as molecular probes for the localized electrical near field of coupled surface plasmon-related resonances and as a way to manipulate dye molecules on a submicron scale.

Kreiter, M.; Neumann, T.; Mittler, S.; Knoll, W.; Sambles, J. R.

2001-08-15

225

Staining paraffin extracted, alcohol rinsed and air dried plant tissue with an aqueous mixture of three dyes.  

PubMed

A staining solution containing alcian blue 8GX, Bismarck brown Y and safranin O was prepared with 0.1 M sodium acetate buffer, pH 5.0. Paraffin was extracted with MicroClear solvent from 10 microm tissue sections mounted on slides. Paraffin solvent was removed by rinsing with isopropanol, and tissues were air dried. Slides with bare dry tissue sections were immersed in the triple stain and structures could be distinguished within 30 min as follows: nonlignified cell walls, blue; lignified cell walls, nuclei and chloroplasts, red; and cuticle, brown or yellow-brown. Excess staining solution was removed by rinsing with tap water, and the tissues were air dried again. Coverslips were affixed with resin over the stained dry tissues. This novel procedure was tested with immature tomato fruit, mature apple fruit, and various leaf and stem specimens of dogwood, laurel, pawpaw, poinsettia and zonal geranium. PMID:9735876

Graham, E T; Trentham, W R

1998-07-01

226

Quantitative diagnosis of cervical neoplasia using fluorescence lifetime imaging on haematoxylin and eosin stained tissue sections.  

PubMed

The use of conventional fluorescence microscopy for characterizing tissue pathological states is limited by overlapping spectra and the dependence on excitation power and fluorophore concentration. Fluorescence lifetime imaging microscopy (FLIM) can overcome these limitations due to its insensitivity to fluorophore concentration, excitation power and spectral similarity. This study investigates the diagnosis of early cervical cancer using FLIM and a neural network extreme learning machine classifier. A concurrently high sensitivity and specificity of 92.8% and 80.2%, respectively, were achieved. The results suggest that the proposed technique can be used to supplement the traditional histopathological examination of early cervical cancer. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim). PMID:23281280

Gu, Jun; Fu, Chit Yaw; Ng, Beng Koon; Gulam Razul, Sirajudeen; Lim, Soo Kim

2014-07-01

227

Measurement of atmospheric OH by titration of near-IR fluorescent dyes  

NASA Technical Reports Server (NTRS)

Recent research has shown that certain polymethine dyes can be detected at ultratrace levels (greater than or equal to 6x10(exp -14) M) in solution by fluorimetry. These detection limits are possible because of the inherent sensitivity of fluorescence techniques, because the dyes fluoresce in the near infrared region where background interference is negligible, and because powerful infrared diode lasers are now available to improve the signal to noise ratio. Other work has shown that the hydroxyl radical destroys the ability of polymethine dyes to fluoresce. These observations form the basis for a new hydroxyl radical detector that is essentially a fluorometric titrator. Theoretically, the detector should show an acceptable sensitivity and response time. Assuming that the atmospheric HO concentration is about 10(exp -11) moles m(exp -3) (i.e. 10(exp 6) molecules cm(exp -3)), then 10 L of air 'titrated' with 20 mL of 10(exp -11) M dye solution (an easily detected concentration) should result in a drop in the fluorescent signal of 50 percent - a readily detectable change. At a flow rate of 3 L min(exp -1) the sampling time would be 3 minutes. The biggest potential problem is selectivity: other oxidants may also cause the fluorescence signal to be lost. The chemistry of polymethine dyes has not been studied in detail and so no quantitative data are available. However, a survey of the literature suggests that in general HO should react up to six orders of magnitude faster than HO2 and other radicals such as RO2 and RO. It should also react much more rapidly than H2O2 and O3. Thus it may be possible to discriminate kinetically against potential interfering substances. It was shown in the laboratory that 10(exp -4) M H2O2 has little effect on the absorption spectrum of the dye IR125 over a period of hours but that the band at 780 nm is slowly lost in water over a period of days even under argon in the dark. By contrast, DMSO solutions of IR125 are stable.

Betterton, Eric A.; Gast, Karl

1994-01-01

228

Phosphorescence and delayed fluorescence properties of fluorone dyes in bio-related films  

NASA Astrophysics Data System (ADS)

The phosphorescence and delayed fluorescence behaviour of the fluorone dyes disodium fluorescein (FL, uranine), 4,5-dibromofluorescein (DBF), eosin Y (EO), erythrosine B (ER), and rose bengal (RB) in bio-films of gelatine, starch, and chitosan at room temperature is studied. Phosphorescence and delayed fluorescence quantum yields and lifetimes were measured. The singlet-triplet dynamics is described and applied to the fluorone dyes for parameter extraction. For uranine films at room temperature no phosphorescence could be resolved. The efficiency of singlet-triplet intersystem crossing increased in the order ? ISC(DBF) < ? ISC(EO) < ? ISC(ER) < ? ISC(RB) due to the heavy atom effect on spin-orbit coupling. The phosphorescence quantum yields increased in the order ? P(DBF) < ? P(EO) < ? P(RB) < ? P(ER). The phosphorescence lifetimes followed the order ? P(DBF) > ? P(EO) > ? P(ER) > ? P(RB).

Penzkofer, ?.; Tyagi, A.; Slyusareva, E.; Sizykh, A.

2010-12-01

229

Solvatochromic behavior on the absorption and fluorescence spectra of Rose Bengal dye in various solvents  

NASA Astrophysics Data System (ADS)

The absorption and fluorescence spectra of Rose Bengal dye were studied in various solvents. It was found that solvent effects on the absorption wavelength are consistent with the solvatochromic model of Kamlet, Abboud and Taft. The solvent polarizability value ?* was found to have a linear relationship with the absorption wavelength of the dye in various solvents. Additionally, the normalized transition energy value ( ETN) showed some scattering when plotted versus ? ?af. Density functional calculations were used to assign the absorption in the region 540-570 nm to a ?- ?* transition between the HOMO and LUMO of the anion. Experimental ground state and excited state dipole moments were calculated by using the solvatochromatic shifts of absorption and fluorescence spectra as a function of the dielectric constant ( ?) and refractive index ( n). The dipole moment for Rose Bengal was found to be 1.72 Debye in the ground state, whereas this value was 2.33 Debye in the excited state.

Rauf, M. A.; Graham, John P.; Bukallah, Saeed B.; Al-Saedi, Mariam A. S.

2009-02-01

230

An assessment of the potential adverse properties of fluorescent tracer dyes used for groundwater tracing.  

PubMed

The potential ecotoxicity of fluorescent dyes used in tracing, and their possible effects on human health, were evaluated by reviewing available toxicological information for 12 dyes - fluorescein, Lissamine Flavine FF, Rhodamine WT, Rhodamine B, Sulpho Rhodamine G, Sulpho Rhodamine B, eosin, pyranine, Phorwite BBH Pure, Tinopal 5BM GX, Tinopal CBS-X, and Diphenyl Brilliant Flavine 7GFF - and a dye-intermediate, amino G acid. This evaluation used available toxicological information, test data on analogous substances, and mathematical expressions for biological activity. Based on set criteria for human health and acute ecotoxicity, the evaluation indicated that these tracers have low to moderate levels of concern. The use of these tracers for the study of groundwater flow is appropriate if consideration is given to the overall human health and environmental effects. Their use in the environment requires tracer concentrations not exceeding 1-2 mg 1(-1) persisting for a period in excess of 24 h in the groundwater at the point of groundwater withdrawal or discharge. A simple calculated potential dose was used in a comparison of the estimated acute toxicity of Rhodamine WT in rats to the known acute oral toxic dose in humans for several known acutely toxic chemicals. This comparison showed that none of the fluorescent dyes evaluated would present an acutely toxic threat at or substantially above the recommended 2 mg 1(-1) concentration. PMID:24197914

Field, M S; Wilhelm, R G; Quinlan, J F; Aley, T J

1995-10-01

231

Near-Wall Motion of Caged Fluorescent Dye in Microchannel Flows Obtained from Evanescent Wave Molecular Tagging  

Microsoft Academic Search

A molecular tagging technique utilizing evanescent wave illumination was developed to investigate the motion of a caged fluorescent dye in the vicinity of the microchannel wall surface in electroosmotic and pressure-driven flows. A line pattern in a buffer solution was written by a pulsed UV laser and the uncaged dye was excited by the evanescent wave with total internal reflection

Yuriko Senga; Tsubasa Nakamura; Hiroki Fukumura; Mitsuhisa Ichiyanagi; Yohei Sato

2010-01-01

232

Fluorescence quenching and photocatalytic degradation of textile dyeing waste water by silver nanoparticles.  

PubMed

Silver nanoparticles (Ag NPs) of different sizes have been prepared by chemical reduction method and characterized using UV-vis spectroscopy and transmission electron microscopy (HRTEM). Fluorescence spectral analysis showed that the quenching of fluorescence of textile dyeing waste water (TDW) has been found to decrease with decrease in the size of the Ag NPs. Experimental results show that the silver nanoparticles can quench the fluorescence emission of adsorbed TDW effectively. The fluorescence interaction between Ag NPs (acceptor) and TDW (donor) confirms the Förster Resonance Energy Transfer (FRET) mechanism. Long range dipole-dipole interaction between the excited donor and ground state acceptor molecules is the dominant mechanism responsible for the energy transfer. Furthermore, photocatalytic degradation of TDW was measured spectrophotometrically by using silver as nanocatalyst under UV light illumination. The kinetic study revealed that synthesized Ag NPs was found to be effective in degrading TDW. PMID:24632164

Kavitha, S R; Umadevi, M; Janani, S R; Balakrishnan, T; Ramanibai, R

2014-06-01

233

Fluorescence quenching and photocatalytic degradation of textile dyeing waste water by silver nanoparticles  

NASA Astrophysics Data System (ADS)

Silver nanoparticles (Ag NPs) of different sizes have been prepared by chemical reduction method and characterized using UV-vis spectroscopy and transmission electron microscopy (HRTEM). Fluorescence spectral analysis showed that the quenching of fluorescence of textile dyeing waste water (TDW) has been found to decrease with decrease in the size of the Ag NPs. Experimental results show that the silver nanoparticles can quench the fluorescence emission of adsorbed TDW effectively. The fluorescence interaction between Ag NPs (acceptor) and TDW (donor) confirms the Förster Resonance Energy Transfer (FRET) mechanism. Long range dipole-dipole interaction between the excited donor and ground state acceptor molecules is the dominant mechanism responsible for the energy transfer. Furthermore, photocatalytic degradation of TDW was measured spectrophotometrically by using silver as nanocatalyst under UV light illumination. The kinetic study revealed that synthesized Ag NPs was found to be effective in degrading TDW.

Kavitha, S. R.; Umadevi, M.; Janani, S. R.; Balakrishnan, T.; Ramanibai, R.

2014-06-01

234

Conformational dependence of energy transfer rate between photochromic molecule and fluorescent dye  

Microsoft Academic Search

The dependence of the energy transfer rate from the fluorescent dye, bis(phenylethynyl)anthracene, to the diarylethene derivative on the dihedral angle around the adamantyl spacer, which is used in the single-molecule photoswitching experiment based on the photochromism [T. Fukaminato, T. Sasaki, T. Kawai, N. Tamai, M. Irie, J. Am. Chem. Soc. 126 (2004) 14843], is examined using the ab initio calculations.

Satoshi Yokojima; Koutaro Ryuo; Masanori Tachikawa; Takao Kobayashi; Katsuya Kanda; Shinichiro Nakamura; Toshikazu Ebisuzaki; Tuyoshi Fukaminato; Masahiro Irie

2007-01-01

235

Vacuolar Chloride Transport in Mesembryanthemum crystallinum L. Measured Using the Fluorescent Dye Lucigenin  

Microsoft Academic Search

.   To study vacuolar chloride (Cl?) transport in the halophilic plant Mesembryanthemum crystallinum L., Cl? uptake into isolated tonoplast vesicles was measured using the Cl?-sensitive fluorescent dye lucigenin (N,N?-dimethyl-9,9?-bisacridinium dinitrate). Lucigenin was used at excitation and emission wavelengths of 433 nm and 506 nm,\\u000a respectively, and showed a high sensitivity towards Cl?, with a Stern-Volmer constant of 173 m\\u000a \\u000a ?1

F. Wissing; J. A. C. Smith

2000-01-01

236

Fabrication of Dye-sensitized Solar Cells and Fluorescence Quenching Study Using Thiophene Based Copolymers  

Microsoft Academic Search

Photovoltaic performance of dye sensitized solar cells fabricated with a commercially available thiophene based copolymer was investigated. Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(bithiophene)], a highly soluble polythiophene, was used as a sensitizer. An open-circuit voltage of 0.64 V and a short-circuit current density of 0.36 mA\\/cm were measured. The incident photon to current conversion efficiency for the polymer was measured. Fluorescence from the other polythiophene,

Soumitra Satapathi; Fadong Yan; Robinson Anandakathir; Ke Yang; Lian Li; Ravi Mosurkal; Lynne A. Samuelson; Jayant Kumar

2010-01-01

237

Oligonucleotide assisted light-emitting Alq3 microrods: energy transfer effect with fluorescent dyes.  

PubMed

Oligonucleotide assisted tri(8-hydroxyquinoline) aluminium (Alq3) microrods were prepared for the first time. When hybridized with oligonucleotide labeled by Cy3 fluorescent dye, a significant photoluminescence variation of the Alq3 microrods was observed due to Förster resonance energy transfer, unlike when Cy5-oligonucleotide was used. Versatile nucleotide manipulation would open up wider applications of Alq3-based materials, based on this fundamental observation. PMID:23535632

Cui, Chunzhi; Park, Dong Hyuk; Kim, Jeongyong; Joo, Jinsoo; Ahn, Dong June

2013-06-14

238

Study of excitation transfer in laser dye mixtures by direct measurement of fluorescence lifetime  

NASA Technical Reports Server (NTRS)

By directly measuring the donor fluorescence lifetime as a function of acceptor concentration in the laser dye mixture Rhodamine 6G-Cresyl violet, we found that the Stern-Volmer relation is obeyed, from which the rate of excitation transfer is determined. The experimental results indicate that the dominant mechanism responsible for the efficient excitation transfer is that of resonance transfer due to long range dipole-dipole interaction.

Lin, C.; Dienes, A.

1973-01-01

239

Fluorescence energy transfer in quantum dot/azo dye complexes in polymer track membranes.  

PubMed

Fluorescence resonance energy transfer in complexes of semiconductor CdSe/ZnS quantum dots with molecules of heterocyclic azo dyes, 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo) resorcinol, formed at high quantum dot concentration in the polymer pore track membranes were studied by steady-state and transient PL spectroscopy. The effect of interaction between the complexes and free quantum dots on the efficiency of the fluorescence energy transfer and quantum dot luminescence quenching was found and discussed. PMID:24172215

Gromova, Yulia A; Orlova, Anna O; Maslov, Vladimir G; Fedorov, Anatoly V; Baranov, Alexander V

2013-01-01

240

New fluorescent symmetrically substituted perylene-3,4,9,10-dianhydride-azohybrid dyes: Synthesis and spectroscopic studies.  

PubMed

Five phenolic azo-dyes (3a-e) were synthesized by diazo coupling of the suitably substituted anilines (1a-e) with phenol at low temperature in alkaline medium. The resulting dyes have low solubility in aqueous medium due to lack of carboxylic or sulfonic solubilizing functionalities. The hybridization of perylene dianhydride with phenolic azo-dyes was achieved by the nucleophilic aromatic substitution (SNAr) reaction of perylene-3,4,9,10-dianhydride 4 with phenolic azo-dyes 3a-e in basic medium. The hybrid dyes exhibit absorption maxima ?max in the range 440-460nm in aqueous medium due to presence of azo linkage and highly conjugated system of ? bonds. Fluorescence spectra of these dyes in water show sharp emission peaks with small band widths. The structures of perylene-azo dyes were confirmed by FTIR and NMR spectroscopy. PMID:24914994

Saeed, Aamer; Shabir, Ghulam

2014-12-10

241

New fluorescent symmetrically substituted perylene-3,4,9,10-dianhydride-azohybrid dyes: Synthesis and spectroscopic studies  

NASA Astrophysics Data System (ADS)

Five phenolic azo-dyes (3a-e) were synthesized by diazo coupling of the suitably substituted anilines (1a-e) with phenol at low temperature in alkaline medium. The resulting dyes have low solubility in aqueous medium due to lack of carboxylic or sulfonic solubilizing functionalities. The hybridization of perylene dianhydride with phenolic azo-dyes was achieved by the nucleophilic aromatic substitution (SNAr) reaction of perylene-3,4,9,10-dianhydride 4 with phenolic azo-dyes 3a-e in basic medium. The hybrid dyes exhibit absorption maxima ?max in the range 440-460 nm in aqueous medium due to presence of azo linkage and highly conjugated system of ? bonds. Fluorescence spectra of these dyes in water show sharp emission peaks with small band widths. The structures of perylene-azo dyes were confirmed by FTIR and NMR spectroscopy.

Saeed, Aamer; Shabir, Ghulam

2014-12-01

242

Design and Synthesis of Efficient Fluorescent Dyes for Incorporation into DNA Backbone and Biomolecule Detection  

PubMed Central

We report here the design and synthesis of a series of ?-conjugated fluorescent dyes with D-A-D (D: donor; A: Acceptor), D-?-D, A-?-A, and D-?-A for applications as the signaling motif in biological-synthetic hybrid foldamers for DNA detection. Horner-Wadsworth-Emmons (HWE) reaction and Knoevenagel condensation were demonstrated as the optimum ways for construction of long ?-conjugated systems. Such rod-like chromophores have distinct advantages, as their fluorescence properties are not quenched by the presence of DNA. To be incorporated into the backbone of DNA, the chromophores need to be reasonably soluble in organic solvent for solid-phase synthesis, and therefore a strategy of using flexible tetra(ethylene glycol) (TEG) linkers at either end of these rod-like dyes were developed. The presence of TEG facilitates the protection of the chain-growing hydroxyl group with DMTrCl (dimethoxy trityl chloride) as well as the activation of the coupling step with phosphoramidite chemistry on an automated DNA synthesizer. To form fluorescence resonance energy transfer (FRET) pairs, six synthetic chromophores with blue to red fluorescence have been developed and those with orthogonal fluorescent emission were chosen for incorporation into DNA-chromophore hybrid foldamers.

Wang, Wei; Li, Alexander D. Q.

2008-01-01

243

Fluorescence Study of DNA–Dye Complexes Using One-Photon and Two-Photon Picosecond Excitation  

Microsoft Academic Search

Preliminary results of investigation of one-photon- and two-photon-induced fluorescence of acridine orange (AO), epirubicin (ER), hypericin (HYP), and ethidium bromide (EB) in complexes with DNA are presented. A spectrofluorometer based on a picosecond Nd:YAG laser was used for investigations of two-photon (1064-nm, 1-mJ, 40-ps) and one-photon (532- and 355-nm) dye excitation. The spectra of two-photon-induced fluorescence of dyes and their

Vladimir A. Hovhannisyan; Lia A. Avanessian

1998-01-01

244

Evaluation of a red fluorescent dye for high-throughput compound screening applications in pharmaceutical discovery research  

NASA Astrophysics Data System (ADS)

The possibility and potential benefits of using an extreme red fluorescent dye such as Cy5.5TM to label drug discovery target proteins was studied experimentally. Cy5.5 labeled BSA, GFP, and CRP were used as examples of protein-dye conjugates whose binding to corresponding antibody was detected by changes in either rotational or transnational diffusion properties, that is, by either fluorescence polarization or confocal fluorescence correlation spectroscopy (FCS). In addition, FCS was used to quantitate excitation of Cy5.5 to its triplet state. Fluorescence polarization and lifetime were measured as a function of excitation wavelength or glycerol concentration and solvent viscosity.

Swift, Kerry M.; Matayoshi, Edmund D.

1999-05-01

245

Carbocyanine dye orientation in red cell membrane studied by microscopic fluorescence polarization.  

PubMed Central

The orientation of an amphipathic, long acyl chain fluorescent carbocyanine dye [diI-C18-(3)] in a biological membrane is examined by steady-state fluorescence polarization microscopy on portions of single erythrocyte ghosts. The thermodynamically plausible orientation model most consistent with the experimental data is one in which the diI-C18-(3) conjugated bridge chromophore is parallel to the surface of the cell and the acyl chains are imbedded in the bilayer parallel to the phospholipid acyl chains. Comparison of the predictions of this model with the experimental data yields information on the intramolecular orientations of the dye's transition dipoles and on the dye's rate of rotation in the membrane around an axis normal to the membrane. To interpret the experimental data, formulae are derived to account for the effect of high aperture observation on fluorescence polarization ratios. These formulae are generally applicable to any high aperture polarization studied on microscopic samples, such as portions of single cells. Images FIGURE 6

Axelrod, D

1979-01-01

246

Sub-diffusion decays in fluorescence correlation spectroscopy: dye photophysics or protein dynamics?  

PubMed

Transitions between bright and dark fluorescent states of several rhodamine dyes were investigated by fluorescence correlation spectroscopy. We resolved two sub-diffusion exponential decays for free rhodamines in aqueous solutions, of which the slower component scales linearly with the viscosity of the solution. Correlation data for proteins and DNA labeled with tetramethylrhodamine were fitted with three to four exponential decays describing flickering dynamics on a time scale between 0.5 and 100 ?s. We investigated the nature of these processes by performing experiments under different experimental conditions and for different samples. On the basis of how their population and lifetime change with viscosity, the oxygen content of the solution, the laser irradiance, and the detection geometry, we assigned these states, in the order of increasing lifetimes, to a triplet state, a hybrid between twisted-intramolecular-charge-transfer state and a ground state lactonic state, a lactonic state, and a photoionized state, respectively. Our data suggests that none of the observed sub-diffusion correlation decays can be directly assigned to the intramolecular dynamics of the labeled biomolecules. However, we found evidence that the intrinsic conformational dynamics of the biomolecule appears in the correlation curves as a modulation of the photophysics of the dye label. This shows the importance of accurate control measurements and appropriate modeling of the dye photophysics in fluorescence correlation studies, and it cautions against direct assignments of dark-state relaxation times to folding kinetics in proteins and nucleic acids. PMID:23675915

Mazouchi, Amir; Bahram, Abdullah; Gradinaru, Claudiu C

2013-09-26

247

Immunological Studies on a Freeze-Substitution Method of Preparing Tissue for Fluorescent Antibody Staining  

PubMed Central

(1) A freeze-substitution, wax embedding method for preparing tissue for fluorescent antibody studies is described. (2) Solutions of ovalbumin and ? globulin were subjected to the whole embedding procedure and their solubility and immunological reactivity estimated quantitatively. It was found that over 60 per cent of these proteins remained soluble after embedding. The precipitating power of the soluble fraction of ovalbumin and antibody globulin was found to be reduced by half. The insoluble fraction of antibody globulin bound more antigen than would be precipitated at equivalence. ImagesFIG. 4FIG. 5

Balfour, Brigid M.

1961-01-01

248

Dynamic staining of Bacillus endospores with Thioflavin T.  

PubMed

Rapid detection and identification of endospores presents a range of complex challenges. Dynamic staining approach, developed in our lab, utilizes the time-course fluorescence enhancement of an amyloid-staining dye, Thioflavin T (ThT), after mixing with intact endospores. We examined the kinetics of staining Bacillus atrophaeus and Bacillus thuringiensis endospores, and the rates of staining were different for the two bacilli when intact endospores were treated with ThT. This finding demonstrates an avenue for attaining information about the sporulated bacterial species without lysing, germinating or other pretreatment steps. PMID:23365938

Upadhyayula, Srigokul; Lam, Samuel; Ha, Alice; Malik-Chaudhry, Harbani K; Vullev, Valentine I

2012-01-01

249

Synthesis and Spectroscopy of Novel Branched Fluorescent Dyes Containing Benzophenone Parts and the Possibility as Fluorescence Probes  

Microsoft Academic Search

This paper describes a new fluorescent family of branched dyes containing benzophenone unit including 4-N, N-diphenylamino-4?-phenacyl-stilbene (C1), 4,4?-di(4-benzoylphenylethylene)yl-triphenylamine (C2) and 4,4?,4?-tri(4-benzoylphenylethylene)yl-triphenylamine (C3). Benzophenone part is coupled with core through C–C double bond. The chemical structures of the derivatives are characterized\\u000a with 1H and 13C nuclear magnetic resonance and elemental analysis. Strong ?–? stacking interactions are discovered with the analysis of

Fang Gao; Lanying Niu; Nvdan Hu; Jianchao Wang; Hongru Li; Shengtao Zhang

2011-01-01

250

What is actually stained by rose bengal?  

PubMed

It has been believed that 1% rose bengal does not stain normal, healthy cells but rather stains degenerated or dead cells and mucous strands. In contrast to this conventional knowledge, we discovered that both commercial additive-containing and additive-free rose bengal solutions stained four different types of healthy cultured cells, including rabbit corneal epithelial cells. Rose bengal staining was rapid, dose dependent, predominantly nuclear, and detectable with the naked eye at concentrations as low as 0.05% and 0.025% for the commercial additive-containing or additive-free solutions, respectively, and with the fluorescence microscope at a concentration of 0.001%. It is surprising to discover that rose bengal is not a vital dye; after staining, cells actually lost vitality, as evidenced by instant morphologic changes, subsequent loss of cellular motility, cell detachment, and cell death. Such an intrinsic toxic effect was augmented by light exposure. The rose bengal staining of live as well as detergent-treated (Triton X-100) cells could be blocked by such tear components as mucin and albumin, suggesting that normally negative rose bengal staining is due to the protective function of the preocular tear film, ie, staining is not dictated by lack of cell vitality. These data indicate that rose bengal staining ensues whenever there is poor protection of surface epithelium by the preocular tear film; this represents a new interpretation for rose bengal stains seen in various ocular surface disorders. PMID:1637285

Feenstra, R P; Tseng, S C

1992-07-01

251

Dictyostelium Extracellular Vesicles Containing Hoechst 33342 Transfer the Dye into the Nuclei of Living Cells: A Fluorescence Study  

Microsoft Academic Search

Cells of the eukaryotic unicellular microorganism Dictyostelium discoideum are constitutively resistant to vital staining of their nuclei by the DNA-specific dye Hoechst 33342. By studying the mechanisms\\u000a of this resistance, we evidenced that these cells expel vesicles containing the dye for detoxification (Tatischeff et al.,\\u000a Cell Mol Life Sci, 54: 476–87, 1998). The question to be addressed in the present

Irène Tatischeff; Françoise Lavialle; Sophie Pigaglio-Deshayes; Christine Péchoux-Longin; Laurent Chinsky; Annette Alfsen

2008-01-01

252

Blood analyte sensing using fluorescent dye-loaded red blood cells  

NASA Astrophysics Data System (ADS)

Measurement of blood analytes provides crucial information about a patient's health. Some such analytes, such as glucose in the case of diabetes, require long-term or near-continuous monitoring for proper disease management. However, current monitoring techniques are far from ideal: multiple-per-day finger stick tests are inconvenient and painful for the patient; implantable sensors have short functional life spans (i.e., 3-7 days). Due to analyte transporters on red blood cell (RBC) membranes that equilibrate intracellular and extracellular analyte levels, RBCs serve as an attractive alternative for encapsulating analyte sensors. Once reintroduced to the blood stream, the functionalized RBCs may continue to live for the remainder of their life span (120 days for humans). They are biodegradable and biocompatible, thereby eliminating the immune system response common for many implanted devices. The proposed sensing system utilizes the ability of the RBCs to swell in response to a decrease in the osmolarity of the extracellular solution. Just before lysis, they develop small pores on the scale of tens of nanometers. While at low temperature, analyte-sensitive dyes in the extracellular solution diffuse into the perforated RBCs and become entrapped upon restoration of temperature and osmolarity. Since the fluorescent signal from the entrapped dye reports on changes in the analyte level of the extracellular solution via the RBC transporters, interactions between the RBCs and the dye are critical to the efficacy of this technique. In this work, we study the use of a near infrared pH sensitive dye encapsulated within RBCs and assess the ability to measure dye fluorescence in vivo.

Ritter, Sarah C.; Shao, Xiaole; Cooley, Nicholas; Milanick, Mark A.; Glass, Timothy E.; Meissner, Kenith E.

2014-02-01

253

Quantification of AAV Particle Titers by Infrared Fluorescence Scanning of Coomassie-Stained Sodium Dodecyl Sulfate-Polyacrylamide Gels  

PubMed Central

Abstract Adeno-associated virus (AAV)-based vectors have gained increasing attention as gene delivery vehicles in basic and preclinical studies as well as in human gene therapy trials. Especially for the latter two—for both safety and therapeutic efficacy reasons—a detailed characterization of all relevant parameters of the vector preparation is essential. Two important parameters that are routinely used to analyze recombinant AAV vectors are (1) the titer of viral particles containing a (recombinant) viral genome and (2) the purity of the vector preparation, most commonly assessed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) followed by silver staining. An important, third parameter, the titer of total viral particles, that is, the combined titer of both genome-containing and empty viral capsids, is rarely determined. Here, we describe a simple and inexpensive method that allows the simultaneous assessment of both vector purity and the determination of the total viral particle titer. This method, which was validated by comparison with established methods to determine viral particle titers, is based on the fact that Coomassie Brilliant Blue, when bound to proteins, fluoresces in the infrared spectrum. Viral samples are separated by SDS–PAGE followed by Coomassie Brilliant Blue staining and gel analysis with an infrared laser-scanning device. In combination with a protein standard, our method allows the rapid and accurate determination of viral particle titers simultaneously with the assessment of vector purity.

Kohlbrenner, Erik; Henckaerts, Els; Rapti, Kleopatra; Gordon, Ronald E.; Linden, R. Michael; Hajjar, Roger J.

2012-01-01

254

Fluorescence lifetime measurements and hole-burning experiments on J-aggregates of a benzimidocarbocyanine dye  

NASA Astrophysics Data System (ADS)

The photophysics of the J-aggregates of the cyanine dye 5,5',6,6'-tetrachloro-1,1'-diethyl-3,3'-bis(4-sulfobutyl)-benzimidazolocarbocyanine (TDBC) has been investigated with fluorescence lifetime measurements and hole-burning experiments. The temperature dependence of the fluorescence lifetime has been measured between 4 and 300 K with different solvent mixtures and different cooling procedures. At very low temperatures, the lifetime is nearly constant under different conditions. Between 50 and 300 K the lifetime depends on solvent mixture and cooling procedure indicating that the microscopic environment of the J-aggregate determines the fluorescence decay. At room temperature the fluorescence lifetime depends linearly on the reciprocal viscosity as would be expected for a diffusion controlled deactivation process under the Stokes—Einstein approximation. From the data, a hydrodynamic volume of 5×10 -28 m 3 can be derived. In contrast to the behavior of pseudoisocyanine (PIC) aggregates, it has been impossible to burn holes in the J-band of TDBC under the given experimental conditions. We conclude that this discrepancy is due to the different aggregate structure of both dyes. In the monomer band of TDBC in ethanol/methanol glass, however, holes can be burnt with prolonged irradiation.

Lindrum, M.; Glismann, A.; Moll, J.; Daehne, S.

1993-12-01

255

Side illumination fluorescence emission characteristics from a dye doped polymer optical fiber under two-photon excitation  

NASA Astrophysics Data System (ADS)

Two-photon excited (TPE) side illumination fluorescence studies in a Rh6G-RhB dye mixture doped polymer optical fiber (POF) and the effect of energy transfer on the attenuation coefficient is reported. The dye doped POF is pumped sideways using 800 nm, 70 fs laser pulses from a Ti:sapphire laser, and the TPE fluorescence emission is collected from the end of the fiber for different propagation distances. The fluorescence intensity of RhB doped POF is enhanced in the presence of Rh6G as a result of energy transfer from Rh6G to RhB. Because of the reabsorption and reemission process in dye molecules, an effective energy transfer is observed from the shorter wavelength part of the fluorescence spectrum to the longer wavelength part as the propagation distance is increased in dye doped POF. An energy transfer coefficient is found to be higher at shorter propagation distances compared to longer distances. A TPE fluorescence signal is used to characterize the optical attenuation coefficient in dye doped POF. The attenuation coefficient decreases at longer propagation distances due to the reabsorption and reemission process taking place within the dye doped fiber as the propagation distance is increased.

Sheeba, M.; Rajesh, M.; Mathew, S.; Nampoori, V. P. N.; Vallabhan, C. P. G.; Radhakrishnan, P.

2008-04-01

256

Red-emitting rhodamines with hydroxylated, sulfonated, and phosphorylated dye residues and their use in fluorescence nanoscopy.  

PubMed

Fluorescent dyes emitting red light are frequently used in conventional and super-resolution microscopy of biological samples, although the variety of the useful dyes is limited. We describe the synthesis of rhodamine-based fluorescent dyes with absorption and emission maxima in the range of 621-637 and 644-660?nm, respectively and demonstrate their high performance in confocal and stimulated emission depletion (STED) microscopy. New dyes were prepared by means of reliable chemical transformations applied to a rhodamine scaffold with three variable positions. They feature polarity, water solubility, variable net charges, improved stabilities of N-hydroxysuccinimidyl (NHS) esters, as well as large fluorescence quantum yields in dye solutions and antibody conjugates. The photophysical and imaging properties of dyes containing three different polar groups, namely primary phosphate, sulfonic acid (in two different positions), and hydroxyl were compared. A dye with two primary phosphate groups was explored as a valuable alternative to dyes with "classical" sulfonic acid groups. Due to the increased net charge of the phosphorylated dye (q=-4 at pH?8), it demonstrated a far better electrophoretic mobility compared with analogues with two sulfonic acid groups (q=-2). As an example, one fluorescent dye was designed to be especially convenient for practical use. It is characterized by sufficiently high chemical stability of the NHS ester, its simple isolation, handling, and solubility in aqueous buffers, as well as in organic solvents. All these features, accompanied by a zero net charge in conjugates, were accomplished by the introduction of hydrophilic groups of two types: two hydroxyl groups and one sulfonic acid residue. PMID:22968960

Kolmakov, Kirill; Wurm, Christian A; Hennig, René; Rapp, Erdmann; Jakobs, Stefan; Belov, Vladimir N; Hell, Stefan W

2012-10-01

257

Ability of laser fluorescence device associated with fluorescent dyes in detecting and quantifying early smooth surface caries lesions.  

PubMed

A laser fluorescence (LF) device is a portable tool, but it does not measure minor mineral changes. Our in vitro study aim is to propose the association of an LF with two fluorescent dyes and to evaluate the performance in detecting and quantifying early demineralization. Artificial caries lesions are created in 40 primary canine teeth using a demineralizing solution (pH=4.8) for 12, 24, 48, and 96 h. LF measurements are performed with DIAGNOdent after demineralization in these samples and in 20 sound primary teeth. Measurements with LF with 0.2-mM tetrakis(N-methylpyridyl)porphyrin (LF TMPyP) and with 4-mM protoporphyrin IX (LF PPIX) are made. The amount of calcium loss is determined by atomic emission spectrometry. A correlation between LF and LF with dyes and mineral loss and receiver operating characteristics analysis are performed, as well as comparisons of sensitivity, specificity, and accuracy values. Significant correlation is obtained with LF TMPyP and mineral loss of lesions demineralized for 24, 48, and 96 h. Better performance is achieved with LF TMPyP for all parameters than with LF alone. LF PPIX does not present good results. In conclusion, LF TMPyP provides good performance in detecting and quantifying very early enamel caries lesions. PMID:16674197

Mendes, Fausto Medeiros; de Oliveira, Elisabeth; de Faria, Dalva Lúcia Araújo; Nicolau, José

2006-01-01

258

Magneto-fluorescent hybrid of dye and SPION with ordered and radially distributed porous structures  

NASA Astrophysics Data System (ADS)

We have reported the development of a silica based magneto-fluorescent hybrid of a newly synthesized dye and superparamagnetic iron oxide nanoparticles with ordered and radially distributed porous structure. The dye is synthesized by a novel yet simple synthetic approach based on Michael addition between dimer of glutaraldehyde and oleylamine molecule. The surfactant used for phase transformation of the dye from organic to aqueous phase, also acts as a structure directing agent for the porous structure evolution of the hybrid with radial distribution. The evolution of the radially distributed pores in the hybrids can be attributed to the formation of rod-like micelles containing nanoparticles, for concentration of micelles greater than critical micelle concentration. A novel water extraction method is applied to remove the surfactants resulting in the characteristic porous structure of the hybrid. Adsorption isotherm analysis confirms the porous nature of the hybrids with pore diameter ?2.4 nm. A distinct modification in optical and magnetic property is observed due to interaction of the dye and SPION within the silica matrix. The integration of multiple structural components in the so developed hybrid nanosystem results into a potential agent for multifunctional biomedical application.

Gogoi, Madhulekha; Deb, Pritam

2014-04-01

259

Combination of Fluorescence In Situ Hybridization with Staining Techniques for Cell Viability and Accumulation of PHA and polyP in Microorganisms in Complex Microbial Systems  

NASA Astrophysics Data System (ADS)

Fluorescence in situ hybridization (FISH) can be combined with a number of staining techniques to reveal the relationships between the microorganisms and their function in complex microbial systems with a single-cell resolution. In this chapter, we have focused on staining methods for intracellular storage compounds (polyhydroxyalkanoates, polyphosphate) and a measure for cell viability, reduction of the tetrazolium-based redox stain CTC. These protocols are optimized for the study of microorganisms in waste-water treatment (activated sludge and biofilms), but they may also be used with minor modifications in many other ecosystems.

Nielsen, Jeppe Lund; Kragelund, Caroline; Nielsen, Per Halkjær

260

Is the central dogma of flow cytometry true: that fluorescence intensity is proportional to cellular dye content  

SciTech Connect

Measurements and theoretical calculations of fluorescent emission from four samples of polystyrene microspheres (diameter 0.92, 1.63, 1.90 and 4.18 ..mu..m) containing the same fluorescent dye show a general dependence upon particle size, emission angle, and polarization conditions. However, for the excitation and detection conditions used in flow cytometry, the relative fluorescent intensities measured for the four particle sizes are proportional to the dye content to +10% accuracy, independent of particle size. Accordingly, the central dogma of flow cytometry that fluorescence is proportional to cellular dye content is valid to this accuracy for these solid, highly refractive polymer particles. Most mammalian cells are much less refractive, therefore, should conform more closely to the central dogma.

Kerker, M.; Van Dilla, M.A.; Brunsting, A.; Kratohvil, J.P.; Hsu, P.; Wang, D.S.; Gray, J.W.; Langlois, R.G.

1982-01-01

261

Subnanosecond single photon counting fluorescence spectroscopy using synchronously pumped tunable dye laser excitation.  

PubMed

A synchronously pumped tunable dye laser has been constructed and interfaced with a modified Ortec 9200 photon counting system for the purpose of measuring subnanosecond relaxation phenomena. The dye laser excitation pulse, which has an intrinsic 35-ps FWHM for Rhodamine 6G, is 350 ps when measured by time-correlated single photon counting. This value appears to be characteristic of the transit time jitter in the RCA 8850 photomultiplier tube. Subnanosecond fluorescence lifetimes of Rhodamine B with KI as a quencher have been determined by deconvolution of photons counted versus elapsed time using the method of moments; the shortest lifetime measured was 68 ps. Various technical aspects of the system are discussed with emphasis on applications to biophysical problems. PMID:18699278

Koester, V J; Dowben, R M

1978-08-01

262

Fluorescent carbocyanine dyes allow living neurons of identified origin to be studied in long-term cultures  

PubMed Central

A prerequisite for many studies of neurons in culture is a means of determining their original identity. We needed such a technique to study the interactions in vitro between a class of spinal cord neurons, sympathetic preganglionic neurons, and their normal target, neurons from the sympathetic chain. Here, we describe how we use two highly fluorescent carbocyanine dyes, which differ in color but are otherwise similar, to identify neurons in culture. The long carbon chain carbocyanine dyes we use are lipid-soluble and so become incorporated into the plasma membrane. Neurons can be labeled either retrogradely or during dissociation. Some of the labeled membrane gradually becomes internalized and retains its fluorescence, allowing identification of cells for several weeks in culture. These dyes do not affect the survival, development, or basic physiological properties of neurons and do not spread detectably from labeled to unlabeled neurons. It seems likely that cells become retrogradely labeled mainly by lateral diffusion of dye in the plane of the membrane. If so, carbocyanine dyes may be most useful for retrograde labeling over relatively short distances. An additional feature of carbocyanine labeling is that neuronal processes are brightly fluorescent for the first few days in culture, presumably because dye rapidly diffuses into newly inserted membrane. We have used carbocyanine dyes to identify sympathetic preganglionic neurons in culture. Our results indicate that preganglionic neurons can survive in the absence of their target cells and that several aspects of their differentiation in the absence of target appear normal.

1986-01-01

263

Laser induced singlet-oxygen-sensitised delayed fluorescence of dyes in aqueous solutions  

SciTech Connect

It is shown that water-soluble derivatives of phthalocyanines - poly(diethoxyphosphinylmethyl)substituted aluminium phthalocyanines - emit intense singlet-oxygen-sensitised delayed fluorescence upon laser-induced formation of singlet oxygen in air-saturated aqueous (D{sub 2}O) solutions. The delayed fluorescence is emitted by the dye molecules which accepted energy from two molecules of singlet oxygen. The quantum efficiency of delayed fluorescence in aerated D{sub 2}O of the chloroaluminium complex of octa(diethoxyphosphinylmethyl) phthalocyanine corresponds to the rate constant of population of excited dye molecules which is equal to (5.5 {+-} 3) x 10{sup 12} mole{sup -2} L{sup 2} s{sup -1}. This value is only an order of magnitude smaller than that for tetra(4-tert.-butyl)phthalocyanine earlier studied in aerated organic solvents. It is shown that these phthalocyanine derivatives can be used as highly sensitive luminescence indicators of singlet oxygen produced in aqueous solutions of different compounds upon laser excitation. (laser applications and other topics in quantum electronics)

Krasnovskii, A A; Bashtanov, M E; Drozdova, N N [A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow (Russian Federation); Yuzhakova, O A; Luk'yanets, Evgenii A [Russian Research Centre 'Research Institute of Organic Intermediates and Dyes', Moscow (Russian Federation)

2002-01-31

264

Is the central dogma of flow cytometry true: that fluorescence intensity is proportional to cellular dye content  

Microsoft Academic Search

Measurements and theoretical calculations of fluorescent emission from four samples of polystyrene microspheres (diameter 0.92, 1.63, 1.90 and 4.18 ..mu..m) containing the same fluorescent dye show a general dependence upon particle size, emission angle, and polarization conditions. However, for the excitation and detection conditions used in flow cytometry, the relative fluorescent intensities measured for the four particle sizes are proportional

M. Kerker; M. A. Van Dilla; A. Brunsting; J. P. Kratohvil; P. Hsu; D. S. Wang; J. W. Gray; R. G. Langlois

1982-01-01

265

High-contrast visualization of graphene oxide on dye-sensitized glass, quartz, and silicon by fluorescence quenching.  

PubMed

We present a novel approach for detecting and visualizing graphene oxide (GO) with high contrast on different substrates, including glass, quartz, and silicon. Visualization of GO sheets is accomplished through quenching the fluorescence of a thiophene dye, giving high optical contrast without the need to use interference methods. A comparison of fluorescence, AFM, and XRD measurements confirmed that even a single GO sheet can completely quench the fluorescence and thus be quickly visualized. PMID:19824679

Treossi, Emanuele; Melucci, Manuela; Liscio, Andrea; Gazzano, Massimo; Samorì, Paolo; Palermo, Vincenzo

2009-11-01

266

Y chromosome visibility in quinacrine-stained human spermatozoa  

Microsoft Academic Search

THE fluorescent dye, quinacrine, binds strongly to the Y chromosome and only to a lesser extent to the other chromosomes in human metaphase cell preparations1. A bright fluorescent spot (F body), which is presumed to be the Y chromosome, is clearly visible in stained interphase cells from various tissues from the human male2-5 and in mature spermatozoa6,7. Spermatozoa bearing one

A. M. Roberts; H. Goodall

1976-01-01

267

Fluorescence energy transfer dye-labeled primers for DNA sequencing and analysis  

SciTech Connect

Fluorescent dye-labeled DNA primers have been developed that exploit fluorescence energy transfer (ET) to optimize the absorption and emission properties of the label. These primers carry a fluorescein derivative at the 5{prime} end as a common donor and other fluorescein and rhodamine derivatives attached to a modified thymidine residue within the primer sequence as acceptors. Adjustment of the donor-acceptor spacing through the placement of the modified thymidine residue within the primer sequence as acceptors. Adjustment of the donor-acceptor spacing through the placement of the modified thymidine in the primer sequence allowed generation of four primers, all having strong absorption at a common excitation wavelength (488 nm) and fluorescence emission maxima of 525,555,580, and 605 nm. The ET efficiency of these primers ranges from 65% to 97%, and they exhibit similar electrophoretic mobilities by gel electrophoresis. With argon-ion laser excitation, the fluorescence of the ET primers and of the DNA sequencing fragments generated with ET primers is 2- to 6-fold greater than that of the corresponding primers or fragments labeled with single dyes. The higher fluorescence intensity of the ET primers allows DNA sequencing with one-fourth of the DNA template typically required when using T7 DNA polymerase. With single-stranded M13mp18 DNA as the template, a typical sequencing reaction with ET primers on a commercial sequencer provided DNA sequences with 99.8% accuracy in the first 500 bases. ET primers should be generally useful in the development of other multiplex DNA sequencing and analysis methods. 29 refs., 5 figs.

Ju, J.; Glazer, A.N.; Mathies, R.A. [Univ. of California, Berkeley, CA (United States); Ruan, C.; Fuller, C.W. [Amersham Life Science Corp., Cleveland, OH (United States)

1995-05-09

268

Photophysical parameters and fluorescence quenching of 7-diethylaminocoumarin (DEAC) laser dye  

NASA Astrophysics Data System (ADS)

The optical properties including electronic absorption spectrum, emission spectrum, fluorescence quantum yield, and dipole moment of electronic transition of 7-diethylaminocoumarin (DEAC) laser dye have been measured in different solvents. Both electronic absorption and fluorescence spectra are red shifted as the polarity of the medium increases, indicating that the dipole moment of molecule increases on excitation. The fluorescence quantum yield of DEAC decreases as the polarity of solvent increases, a result of the role of solvent polarity in stabilization of the twisting of the intramolecular charge transfer (TICT) in excited state, which is a non-emissive state, as well as hydrogen bonding with the hetero-atom of dye. The emission spectrum of DEAC has also been measured in cationic (CTAC) and anionic (SDS) micelles, the intensity increases as the concentration of surfactant increases, and an abrupt change in emission intensity is observed at critical micelle concentration (CMC) of surfactant. 2×10 -3 mol dm -3 of DEAC gives laser emission in the blue region on pumping with nitrogen laser ( ?ex=337.1 nm). The laser parameters such as tuning range, gain coefficient ( ?), emission cross section ( ?e), and half-life energy have been calculated in different solvents, namely acetone, dioxane , ethanol, and dimethyforamide (DMF). The photoreactivity of DEAC has been studied in CCl 4 at a wavelength of 366 nm. The values of photochemical yield ( ?c) and rate constant ( k) are determined. The interaction of organic acceptors such as picric acid (PA), tetracyanoethylene (TCNE), and 7,7,8,8-tetracynoquinonedimethane (TCNQ) with DEAC is also studied using fluorescence measurements in acetonitrile (CH 3CN); from fluorescence quenching study we assume the possible electron transfer from excited donor DEAC to organic acceptor forming non-emissive exciplex.

El-Mossalamy, E. H.; Obaid, A. Y.; El-Daly, S. A.

2011-10-01

269

Non-linear fluorescence in dye solutions induced by a low power laser  

NASA Astrophysics Data System (ADS)

Measurements of the fluorescence intensity IF, excited by two-photon pumping, have been carried out in different dye solutions by utilizing a low power cw laser ( IL ? 12 mW) and a particular experimental technique. A considerable departure from the quadratic law IF ? I2L with the varying of 2 h? - ?Ei quantity has been detected. This behaviour has bee n accounted for by considering the dependence of the non-linear and linear cross sections relative to the S 0 ? S 1 and S 0 ? S 2 transitions on the laser frequency.

Catalano, I. M.; Cingolani, A.

1980-01-01

270

Study of foxing stains on paper by chemical methods, infrared spectroscopy, micro-X-ray fluorescence spectrometry and laser induced breakdown spectroscopy  

Microsoft Academic Search

Foxing spots appear on the paper as stains of reddish-brown, brown or yellowish color, generally of small dimensions, with sharp or irregular edges, most of which, if excited with UV light, show fluorescence. The formation mechanisms of foxed areas have been studied since 1935, however, despite more recent intensive research there are still no conclusive results. Some authors found evidence

M. Bicchieri; S Ronconi; F. P Romano; L Pappalardo; M Corsi; G Cristoforetti; S Legnaioli; V Palleschi; A Salvetti; E Tognoni

2002-01-01

271

Rapid detection of total and viable Legionella pneumophila in tap water by immunomagnetic separation, double fluorescent staining and flow cytometry  

PubMed Central

Summary We developed a rapid detection method for Legionella pneumophila (Lp) by filtration, immunomagnetic separation, double fluorescent staining, and flow cytometry (IMS?FCM method). The method requires 120?min and can discriminate ‘viable’ and ‘membrane?damaged’ cells. The recovery is over 85% of spiked Lp SG 1 cells in 1?l of tap water and detection limits are around 50 and 15 cells per litre for total and viable Lp, respectively. The method was compared using water samples from house installations in a blind study with three environmental laboratories performing the ISO 11731 plating method. In 53% of the water samples from different taps and showers significantly higher concentrations of Lp were detected by flow cytometry. No correlation to the plate culture method was found. Since also ‘viable but not culturable’ (VNBC) cells are detected by our method, this result was expected. The IMS?FCM method is limited by the specificity of the used antibodies; in the presented case they target Lp serogroups 1–12. This and the fact that no Lp?containing amoebae are detected may explain why in 21% of all samples higher counts were observed using the plate culture method. Though the IMS?FCM method is not yet fit to completely displace the established plating method (ISO 11731) for routine Lp monitoring, it has major advantages to plating and can quickly provide important insights into the ecology of this pathogen in water distribution systems.

Keserue, Hans-Anton; Baumgartner, Andreas; Felleisen, Richard; Egli, Thomas

2012-01-01

272

Energy transfer processes in dye-doped nanostructures yield cooperative and versatile fluorescent probes.  

PubMed

Fast and efficient energy transfer among dyes confined in nanocontainers provides the basis of outstanding functionalities in new-generation luminescent probes. This feature article provides an overview of recent research achievements on luminescent Pluronic-Silica NanoParticles (PluS NPs), a class of extremely monodisperse core-shell nanoparticles whose design can be easily tuned to match specific needs for diverse applications based on luminescence, and that have already been successfully tested in in vivo imaging. An outline of their outstanding properties, such as tuneability, bright and photoswitchable fluorescence and electrochemiluminescence, will be supported by a critical discussion of our recent works in this field. Furthermore, novel data and simulations will be presented to (i) thoroughly examine common issues arising from the inclusion of multiple dyes in a small silica core, and (ii) show the emergence of a cooperative behaviour among embedded dyes. Such cooperative behaviour provides a handle for fine control of brightness, emission colour and self-quenching phenomena in PluS NPs, leading to significantly enhanced signal to noise ratios. PMID:24531884

Genovese, Damiano; Rampazzo, Enrico; Bonacchi, Sara; Montalti, Marco; Zaccheroni, Nelsi; Prodi, Luca

2014-03-21

273

Detection of microlesions induced by heavy ions using liposomes filled with fluorescent dye  

NASA Technical Reports Server (NTRS)

In cells irradiation by heavy ions has been hypothesized to produce microlesions, regions of local damage. In cell membranes this damage is thought to manifest itself in the form of holes. The primary evidence for microlesions comes from morphological studies of cell membranes, but this evidence is still controversial, especially since holes also have been observed in membranes of normal, nonirradiated, cells. However, it is possible that damage not associated with histologically discernable disruptions may still occur. In order to resolve this issue, we developed a system for detecting microlesions based on liposomes filled with fluorescent dye. We hypothesized that if microlesions form in these liposomes as the result of irradiation, then the entrapped dye will leak out into the surrounding medium in a measurable way. Polypropylene vials containing suspensions of vesicles composed of either dipalmitoyl phosphatidylcholine, or a combination of egg phosphatidylcholine and cholesterol were irradiated at the Brookhaven National Laboratory using 56Fe ions at 1 GeV/amu. In several cases we obtained a significant loss of the entrapped dye above the background level. Our results suggest that holes may form in liposomes as the result of heavy ion irradiation, and that these holes are large enough to allow leakage of cell internal contents that are at least as large as a 1 nm diameter calcein molecule. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Koniarek, J. P.; Thomas, J. L.; Vazquez, M.

2004-01-01

274

Energy transfer processes in dye-doped nanostructures yield cooperative and versatile fluorescent probes  

NASA Astrophysics Data System (ADS)

Fast and efficient energy transfer among dyes confined in nanocontainers provides the basis of outstanding functionalities in new-generation luminescent probes. This feature article provides an overview of recent research achievements on luminescent Pluronic-Silica NanoParticles (PluS NPs), a class of extremely monodisperse core-shell nanoparticles whose design can be easily tuned to match specific needs for diverse applications based on luminescence, and that have already been successfully tested in in vivo imaging. An outline of their outstanding properties, such as tuneability, bright and photoswitchable fluorescence and electrochemiluminescence, will be supported by a critical discussion of our recent works in this field. Furthermore, novel data and simulations will be presented to (i) thoroughly examine common issues arising from the inclusion of multiple dyes in a small silica core, and (ii) show the emergence of a cooperative behaviour among embedded dyes. Such cooperative behaviour provides a handle for fine control of brightness, emission colour and self-quenching phenomena in PluS NPs, leading to significantly enhanced signal to noise ratios.

Genovese, Damiano; Rampazzo, Enrico; Bonacchi, Sara; Montalti, Marco; Zaccheroni, Nelsi; Prodi, Luca

2014-02-01

275

On the incorporation of Rhodamine B and 2?,7?-dichlorofluorescein dyes in silica: Synthesis of fluorescent nanoparticles  

NASA Astrophysics Data System (ADS)

The present paper reports the incorporation of 2?,7?-dichlorofluorescein (DCF) and Rhodamine B (RhB) dyes in silica nanoparticles by using the Stöber's method with some modifications. Based on infrared and electronic spectroscopies, these dyes were successfully incorporated resulting in fluorescent nanomaterials of an average size of 80 nm. A composite fluorescent nanomaterial containing both dyes was also synthesized and showed the occurrence of Förster resonant energy transfer process (FRET) with the average distance between the donor (DCF) and acceptor (RhB) of 3.6 nm. Furthermore, these fluorescent nanoparticles were modified with folic acid producing nanomaterials whose Zeta potential values were in the range of ?2 to ?13 mV. These values are consistent with the low dispersivity observed by TEM micrographs. Altogether, these suitable properties can lead to the development of nanomaterials for cancer bioimaging and drug release.

Gomes, Elis C. C.; de Carvalho, Idalina M. M.; Diógenes, Izaura C. N.; de Sousa, Eduardo H. S.; Longhinotti, Elisane

2014-05-01

276

Dye analysis of Shosoin textiles using excitation-emission matrix fluorescence and ultraviolet-visible reflectance spectroscopic techniques.  

PubMed

The dyes of 8th century textiles, treasured for more than 1250 years in the Shosoin treasure repository in Japan, were analyzed by nondestructive methods, i.e., excitation-emission matrix (EEM) fluorescence and ultraviolet-visible (UV-vis) reflectance spectrometry, in combination with natural dye references extracted from plants, which have been widely used from ancient times. In this analysis, five dyes were found in the following objects: embroidered shoes dedicated to Great Buddha of the Todaiji temple by the empress of that time, the cloth lining for a case holding a mirror belonging to the emperor of that time, two rolls of yellow and light green plain-weave silks, and a sleeveless coat used for a musical in a Buddhist ceremony in 752 A.D. EEM fluorescence spectrometry distinguished kihada yellow (Amur cork tree), kariyasu yellow (eulalia), and akane red (Japanese madder). UV-vis spectrometry also distinguished kariyasu yellow, ai blue (knotweed), akane red, and shikon purple (murasaki); the characteristic peaks of these dyes were detected by a second derivatization. The results show that although the dyes used easily degrade with age, EEM fluorescence and UV-vis reflectance spectrometry are useful for distinguishing dyes used in the Shosoin textiles, which had been stored for more than 1250 years. PMID:19507884

Nakamura, Rikiya; Tanaka, Yoko; Ogata, Atsuhiko; Naruse, Masakazu

2009-07-15

277

Fluorescent staining of glycoproteins in sodium dodecyl sulfate polyacrylamide gels by 4H-[1]-benzopyrano[4,3-b]thiophene-2-carboxylic acid hydrazide.  

PubMed

A fluorescent detection method for glycoproteins in SDS-PAGE by using 4H-[1]-benzopyrano[4,3-b]thiophene-2-carboxylic acid hydrazide (BH) was developed in this study. As low as 4-8 ng glycoproteins (transferrin, ?1-acid glycoprotein) could be specifically detected by the BH staining method, which is twofold more sensitive than that of the most commonly used Pro-Q Emerald 488 glycoprotein stain. Furthermore, the specificity of the newly developed stain for glycoproteins was demonstrated by 1-D and 2-D SDS-PAGE, deglycosylation, glycoprotein affinity enrichment and LC-MS/MS, respectively. According to the results, it is concluded that BH stain may provide new choices for convenient, sensitive, specific and economic visualization of gel-separated glycoproteins. PMID:24712021

Zhu, Zhongxin; Zhou, Xuan; Wang, Yang; Chi, Lisha; Ruan, Dandan; Xuan, Yuanhu; Cong, Weitao; Jin, Litai

2014-06-01

278

Factors underlying membrane potential-dependent and -independent fluorescence responses of potentiometric dyes in stressed cells: diSC 3(3) in yeast  

Microsoft Academic Search

The redistribution fluorescent dye diS-C3(3) responds to yeast plasma membrane depolarisation or hyperpolarisation by ??-dependent outflow from or uptake into the cells, reflected in changes in the fluorescence maximum ?max and fluorescence intensity. Upon membrane permeabilisation the dye redistributes between the cell and the medium in a purely concentration-dependent manner, which gives rise to ??-independent fluorescence responses that may mimic

D. Gášková; R. ?adek; R. Chaloupka; J. Plášek; K. Sigler

2001-01-01

279

Comparison of Pollen Transfer Dynamics by Multiple Floral Visitors: Experiments with Pollen and Fluorescent Dye  

PubMed Central

• Background and Aims Most plant species are visited by a diversity of floral visitors. Pollen transfer of the four most common pollinating bee species and one nectar-robbing bee of the distylous plant Gelsemium sempervirens were compared. • Methods Naturally occurring pollen loads carried by the common floral visitor species of G. sempervirens were compared. In addition, dyed pollen donor flowers and sequences of four emasculated recipient flowers in field cages were used to estimate pollen transfer, and the utility of fluorescent dye powder as an analogue for pollen transfer was determined. • Key Results Xylocopa virginica, Osmia lignaria and Habropoda laboriosa carried the most G. sempervirens pollen on their bodies, followed by Bombus bimaculatus and Apis mellifera. However, B. bimaculatus, O. lignaria and H. laboriosa transferred significantly more pollen than A. mellifera. Nectar-robbing X. virginica transferred the least pollen, even when visiting legitimately. Dye particles were strongly correlated with pollen grains on a stigma, and therefore provide a good analogue for pollen in this system. The ratio of pollen?:?dye across stigmas was not affected by bee species or interactions between bee species and floral morphology. However, dye transfer was more sensitive than pollen transfer to differences in floral morphology. • Conclusions The results from this study add to a growing body of literature highlighting that floral visitors vary in pollination effectiveness, and that visitors carrying the most pollen on their bodies may not always be the most efficient at depositing pollen on stigmas. Understanding the magnitude of variability in pollinator quality is one important factor for predicting how different pollinator taxa may influence the evolution of floral traits.

ADLER, LYNN S.; IRWIN, REBECCA E.

2006-01-01

280

Apparatus for eliminating background interference in fluorescence measurements  

DOEpatents

The disclosure is directed to an apparatus for eliminating background interference during fluorescence measurements in a multiple laser flow cytometer. A biological particle stained with fluorescent dyes is excited by a laser. A fluorescence detector detects the fluorescence. The particle scatters light and a gate signal is generated and delayed until the biological particle reaches the next laser. The delayed signal turns on this next laser which excites a different stained component of the same biological particle.

Martin, J.C.; Jett, J.H.

1984-01-06

281

Apparatus for eliminating background interference in fluorescence measurements  

DOEpatents

The disclosure is directed to an apparatus for eliminating background interference during fluorescence measurements in a multiple laser flow cytometer. A biological particle stained with fluorescent dyes is excited by a laser. A fluorescence detector detects the fluorescence. The particle scatters light and a gate signal is generated and delayed until the biological particle reaches the next laser. The delayed signal turns on this next laser, which excites a different stained component of the same biological particle. 8 figs.

Martin, J.C.; Jett, J.H.

1986-03-04

282

Apparatus for eliminating background interference in fluorescence measurements  

DOEpatents

The disclosure is directed to an apparatus for eliminating background interference during fluorescence measurements in a multiple laser flow cytometer. A biological particle stained with fluorescent dyes is excited by a laser. A fluorescence detector detects the fluorescence. The particle scatters light and a gate signal is generated and delayed until the biological particle reaches the next laser. The delayed signal turns on this next laser, which excites a different stained component of the same biological particle.

Martin, John C. (Los Alamos, NM); Jett, James H. (Los Alamos, NM)

1986-01-01

283

Metal enhanced fluorescence of Me-ADOTA·Cl dye by silver triangular nanoprisms on a gold film  

NASA Astrophysics Data System (ADS)

In this Letter we discuss the plasmonic scattering and fluorescence enhancement properties of silver triangular nanoprisms synthesized by a chemical reduction method. Plasmonic platforms (PPs) were made by air-dried self-assembly of the silver triangular nanoprisms onto a gold mirror. Fluorescence enhancement was investigated using methyl-azadioxatriangulenium chloride (Me-ADOTA·Cl) dye in PVA deposited on PPs. Confocal microscopy results showed a 15-fold enhancement of the dye overall, with over 50-fold enhancements on 'hot spot' regions. The presence of silver nanoprisms significantly reduced the lifetime of the fluorophore. The preparation of silver triangular nanoprisms and observed emission data are highly reproducible.

Folmar, Michele; Shtoyko, Tanya; Fudala, Rafal; Akopova, Irina; Gryczynski, Zygmunt; Raut, Sangram; Gryczynski, Ignacy

2012-04-01

284

Quantification of free cysteines in membrane and soluble proteins using a fluorescent dye and thermal unfolding  

PubMed Central

Cysteine is an extremely useful site for selective attachment of labels to proteins for many applications, including the study of protein structure in solution by electron paramagnetic resonance (EPR), fluorescence spectroscopy and medical imaging. The demand for quantitative data for these applications means that it is important to determine the extent of the cysteine labeling. The efficiency of labeling is sensitive to the 3D context of cysteine within the protein. Where the label or modification is not directly measurable by optical or magnetic spectroscopy, for example, in cysteine modification to dehydroalanine, assessing labeling efficiency is difficult. We describe a simple assay for determining the efficiency of modification of cysteine residues, which is based on an approach previously used to determine membrane protein stability. The assay involves a reaction between the thermally unfolded protein and a thiol-specific coumarin fluorophore that is only fluorescent upon conjugation with thiols. Monitoring fluorescence during thermal denaturation of the protein in the presence of the dye identifies the temperature at which the maximum fluorescence occurs; this temperature differs among proteins. Comparison of the fluorescence intensity at the identified temperature between modified, unmodified (positive control) and cysteine-less protein (negative control) allows for the quantification of free cysteine. We have quantified both site-directed spin labeling and dehydroalanine formation. The method relies on a commonly available fluorescence 96-well plate reader, which rapidly screens numerous samples within 1.5 h and uses <100 ?g of material. The approach is robust for both soluble and detergent-solubilized membrane proteins.

Hagelueken, Gregor; Naismith, James H

2013-01-01

285

Quantification of free cysteines in membrane and soluble proteins using a fluorescent dye and thermal unfolding.  

PubMed

Cysteine is an extremely useful site for selective attachment of labels to proteins for many applications, including the study of protein structure in solution by electron paramagnetic resonance (EPR), fluorescence spectroscopy and medical imaging. The demand for quantitative data for these applications means that it is important to determine the extent of the cysteine labeling. The efficiency of labeling is sensitive to the 3D context of cysteine within the protein. Where the label or modification is not directly measurable by optical or magnetic spectroscopy, for example, in cysteine modification to dehydroalanine, assessing labeling efficiency is difficult. We describe a simple assay for determining the efficiency of modification of cysteine residues, which is based on an approach previously used to determine membrane protein stability. The assay involves a reaction between the thermally unfolded protein and a thiol-specific coumarin fluorophore that is only fluorescent upon conjugation with thiols. Monitoring fluorescence during thermal denaturation of the protein in the presence of the dye identifies the temperature at which the maximum fluorescence occurs; this temperature differs among proteins. Comparison of the fluorescence intensity at the identified temperature between modified, unmodified (positive control) and cysteine-less protein (negative control) allows for the quantification of free cysteine. We have quantified both site-directed spin labeling and dehydroalanine formation. The method relies on a commonly available fluorescence 96-well plate reader, which rapidly screens numerous samples within 1.5 h and uses <100 ?g of material. The approach is robust for both soluble and detergent-solubilized membrane proteins. PMID:24091556

Branigan, Emma; Pliotas, Christos; Hagelueken, Gregor; Naismith, James H

2013-11-01

286

Ratiometric optical temperature sensor using two fluorescent dyes dissolved in an ionic liquid encapsulated by Parylene film.  

PubMed

A temperature sensor that uses temperature-sensitive fluorescent dyes is developed. The droplet sensor has a diameter of 40 µm and uses 1 g/L of Rhodamine B (RhB) and 0.5 g/L of Rhodamine 110 (Rh110), which are fluorescent dyes that are dissolved in an ionic liquid (1-ethyl-3-methylimidazolium ethyl sulfate) to function as temperature indicators. This ionic liquid is encapsulated using vacuum Parylene film deposition (which is known as the Parylene-on-liquid-deposition (PoLD) method). The droplet is sealed by the chemically stable and impermeable Parylene film, which prevents the dye from interacting with the molecules in the solution and keeps the volume and concentration of the fluorescent material fixed. The two fluorescent dyes enable the temperature to be measured ratiometrically such that the droplet sensor can be used in various applications, such as the wireless temperature measurement of microregions. The sensor can measure the temperature of such microregions with an accuracy of 1.9 °C, a precision of 3.7 °C, and a fluorescence intensity change sensitivity of 1.0%/K. The sensor can measure temperatures at different sensor depths in water, ranging from 0 to 850 µm. The droplet sensor is fabricated using microelectromechanical system (MEMS) technology and is highly applicable to lab-on-a-chip devices. PMID:23535716

Kan, Tetsuo; Aoki, Hironori; Binh-Khiem, Nguyen; Matsumoto, Kiyoshi; Shimoyama, Isao

2013-01-01

287

Vapor-phase staining of cyanoacrylate-fumed latent fingerprints using p-dimethylaminobenzaldehyde.  

PubMed

Contrasting or enhancing of cyanoacrylate ester-fumed latent fingerprints deposited on solvent-sensitive materials such as oil marker writings and rough surface materials such as unglazed earthenware is not easy by conventional dye solutions dipping or dye powder dusting. In this study, a new vapor-phase staining method using p-dimethylaminobenzaldehyde (DMAB) is proposed for staining such materials. DMAB has high volatility and selective absorbability to cyanoacrylate-fumed fingerprints, so that cyanoacrylate-treated samples can be easily stained by leaving them simply in a closed container along with DMAB crystals for 48-96 h at room temperature or in conjunction with the use of mild heating. The stained fingerprint could be excited by UV irradiation (365 nm), and the fluorescent fingerprint was photographed through a UV cut-off filter (420 nm). The new method achieved minimally destructive fluorescent staining for the solvent-sensitive samples and the rough surfaced samples. PMID:22103265

Takatsu, Masahisa; Shimoda, Osamu; Teranishi, Hiroyoshi

2012-03-01

288

Vital-dye enhanced fluorescence imaging of gastrointestinal mucosa: metaplasia, neoplasia, inflammation  

PubMed Central

Background Confocal endomicroscopy has revolutionized endoscopy by offering sub-cellular images of gastrointestinal epithelium; however, field-of-view is limited. There is a need for multi-scale endoscopy platforms that use widefield imaging to better direct placement of high-resolution probes. Design Feasibility Study Objective This study evaluates the feasibility of a single agent, proflavine hemisulfate, as a contrast medium during both widefield and high resolution imaging to characterize morphologic changes associated with a variety of gastrointestinal conditions. Setting U.T. M.D. Anderson Cancer Center (Houston, TX) and Mount Sinai Medical Center (New York, NY) Patients, Interventions, and Main Outcome Measurements Surgical specimens were obtained from 15 patients undergoing esophagectomy/colectomy. Proflavine, a vital fluorescent dye, was applied topically. Specimens were imaged with a widefield multispectral microscope and a high-resolution microendoscope. Images were compared to histopathology. Results Widefield-fluorescence imaging enhanced visualization of morphology, including the presence and spatial distribution of glands, glandular distortion, atrophy and crowding. High-resolution imaging of widefield-abnormal areas revealed that neoplastic progression corresponded to glandular heterogeneity and nuclear crowding in dysplasia, with glandular effacement in carcinoma. These widefield and high-resolution image features correlated well with histopathology. Limitations This imaging approach must be validated in vivo with a larger sample size. Conclusions Multi-scale proflavine-enhanced fluorescence imaging can delineate epithelial changes in a variety of gastrointestinal conditions. Distorted glandular features seen with widefield imaging could serve as a critical ‘bridge’ to high-resolution probe placement. An endoscopic platform combining the two modalities with a single vital-dye may facilitate point-of-care decision-making by providing real-time, in vivo diagnoses.

Muldoon, Timothy J; Polydorides, Alexandros D; Maru, Dipen M; Harpaz, Noam; Harris, Michael T; Hofstettor, Wayne; Hiotis, Spiros P; Kim, Sanghyun A; Ky, Alex J; Anandasabapathy, Sharmila; Richards-Kortum, Rebecca

2012-01-01

289

Wood stains  

MedlinePLUS

Wood stains are products used for wood finishing. Wood stain poisoning occurs when someone swallows these substances. This is ... Various wood stains Note: This list does not include all sources of wood stain.

290

Application of photoacoustic, photothermal and fluorescence spectroscopies in signal enhancement and the kinetics, chemistry and photophysics of several dyes  

SciTech Connect

Modified photoacoustic and photothermal spectroscopies are applied in analytical studies of liquid and solid systems. Quenching of benzophenone by potassium iodide is used to demonstrate application of time resolved photothermal spectroscopies in study of fast (submicrosecond) deexcitation processes. Inherently weak X-ray photoacoustic signals at a synchrotron are enhanced by the introduction of a volatile liquid into a gas-microphone photoacoustic cell. Traditionally, photoacoustic signals have been detected either by gas coupling with a microphone or with a piezoelectric detector. However, optically detected photoacoustic signals have been used in the determination of physical properties of a liquid sample system and are successfully applied to the study of deexcitation processes of a number of dye molecules. Photothermal beam deflection photoacoustic (PBDPA), fluorescence and absorbance measurements are utilized to study the chemistry and photophysics of cresyl violet in aqueous, aqueous micellar and methanolic solutions. A concentration dependence of the fluorescence quantum yield of cresyl violet is investigated. Aspects of chemistry and photophysics relating to potential use of several diazo dyes as photothermal sensitizing dyes in photodynamic therapy are explored experimentally and discussed. Photothermal beam deflection, fluorescence and absorbance measurements are again utilized. The dyes are found to have a number of interesting chemical and photophysical properties. They are also determined to be ideal photothermal sensitizing dye candidates.

Isak, S.J.

1992-06-01

291

Characterization of the vitreous body of the human eye using a cyanine dye as a spectral and fluorescent probe  

NASA Astrophysics Data System (ADS)

We used one of cyanine dyes as a spectral and fluorescent probe in the study of the composition of the extracellular matrix of the human eye (its vitreous body). Owing to the unique ability of the dye to bind to collagens and human serum albumin, we revealed the simultaneous presence of both types of biomacromolecules in the vitreous body. The formation of the dye complex with human serum albumin leads to appearance of a long-wavelength absorption band (~612 nm) and a steep rise of fluorescence, whereas in the presence of collagens the dye forms J-aggregates with a longer-wavelength absorption band (640-660 nm) and moderate fluorescence. In this work we studied the composition of the human fetus vitreous body and its dynamics from 9 to 31 gestation weeks. On the basis of the data obtained by this method, we may assume that albumin, being a carrier protein, probably provides the vitreous body and surrounding tissues with necessary growth factors, hormones, lipids, vitamins, and some other biomolecules. The data show that the dye is promising not only for study of albumin functions in eye development, but also for characterization of some eye diseases and for analysis of other extracellular media.

Panova, Ina G.; Tatikolov, Alexander S.

2009-02-01

292

Rational Approach to Select Small Peptide Molecular Probes Labeled with Fluorescent Cyanine Dyes for in vivo Optical Imaging  

PubMed Central

We demonstrate that the structure of carbocyanine dyes, which are commonly used to label small peptides for molecular imaging, and not the bound peptide, controls the rate of extravasation from blood vessels to tissue. By examining several near-infrared (NIR) carbocyanine fluorophores, we demonstrate a quantitative correlation between the binding of a dye to albumin, a model plasma protein, and the rate of extravasation of the probe into tissue. Binding of the dyes was measured by fluorescence quenching of the tryptophans in albumin and was found to be inversely proportional to the rate of extravasation. The rate of extravasation, determined by kurtosis from longitudinal imaging studies using rodent ear models, provided a basis for quantitative measurements. Structure-activity studies aimed at evaluating a representative library of NIR fluorescent cyanine probes showed that hydrophilic dyes with binding constants several orders of magnitude lower than their hydrophobic counterparts have much faster extravasation rate, establishing a foundation for rational probe design. The correlation provides a guideline for dye selection in optical imaging and a method to verify if a certain dye is optimal for a specific molecular imaging application

Berezin, Mikhail Y.; Guo, Kevin; Akers, Walter; Livingston, Joseph; Solomon, Metasebya; Lee, Hyeran; Liang, Kexian; Agee, Anthony; Achilefu, Samuel

2011-01-01

293

Fluorescent nanomicelles for selective detection of Sudan dye in Pluronic F127 aqueous media.  

PubMed

Novel self-assembled water-soluble nanomicelles that contain fluorescent conjugated polymers (poly(9,9-dioctylfluorene) (PFO) or poly[2,7-(9,9-dihexylfluorene)-alt-4,4'-phenylether] (PF-PE)) have been obtained and used as the highly sensitive/selective platform for Sudan dye detection. The Fluorescent nanomicelles exhibited a highly selective fluorescence quenching by the prohibited food additive Sudan I, while not for the natural pigments: Capsanthin and Beta-carotene, due to the more suitable matching of the LUMOs (lowest unoccupied molecular orbital) of the conjugated polymers with that of Sudan I molecules. The Stern-Volmer constants (K(SV)) of PF-PE/F127 and PFO/F127 for Sudan I were 1,040,480 and 665,000 M(-1), respectively, which were more than 100 times higher than those of the same conjugated polymers in the orgainc solvents. The significantly enhanced sensitivity was due to the collective effect of the F127 micelles to both chromophore and analyte, through which the fluorophone-analyte binding interaction is significantly strengthened and efficient photoinduced charge transfer occurs. The as-proposed materials and approach may be potentially applied in the real-time food safety screening. PMID:24625370

Ye, Xinliang; Zhang, Jie; Chen, Hui; Wang, Xiaohui; Huang, Fei

2014-04-01

294

The relation between dicarbocyanine dye fluorescence and the membrane potential of human red blood cells set at varying Donnan equilibria  

PubMed Central

The fluorescence, F, of two dicarbocyanine dyes, diS-C3(5) and diI- C3(5), depends both on the membrane potential, E, and on the intracellular pH, pHc, or human red blood cells. Compositions of isotonic media have been devised in which the equilibrium Donnan potential, E, varies at constant pHc and in which pHc varies at constant E. Dye fluorescence measurements in these suspensions yield calibrations of +1.7 % delta F/mV for diS-C3(5) and +0.6 % delta F/mV for diI-C3 (5). While pHo does not affect F of either dye, changes in pHc of 0.1 unit at constant E cause changes of F equivalent to those induced by 2--3mV. Based on these results, a method is given for estimating changes in E from dye fluorescence in experiments in which E and pHc co-vary. The relation of F to E also depends in a complex way on the type and concentration of cells and dye, and the wavelengths employed. The equilibrium calibration of dye fluorescence, when applied to diffusion potentials induced by 1 microM valinomycin, yields a value for the permeability ratio, PK.VAL/PCl, of 20 +/- 5, in agreement with previous estimates by other methods. The calibration of F is identical both for diffusion potentials and for equilibrium potentials, implying that diC-C3(5) responds to changes in voltage independently of ionic fluxes across the red cell membrane. Changes in the absorption spectra of dye in the presence of red cells in response to changes in E show that formation of nonfluorescent dimers contributes to fluorescence quenching of diS-C3(5). In contrast, only a hydrophobic interaction of dye monomers need be considered for diI-C3(5), indicating the occurrence of a simpler mechanism of fluorescence quenching.

1979-01-01

295

An analysis of seed development in Pisum sativum V. Fluorescence triple staining for investigating cotyledon cell development  

Microsoft Academic Search

Summary A triple staining technique has been developed to investigate the relationship between the increase in DNA content and initiation of storage protein synthesis in pea cotyledon cells. Cells were separated by incubation with macerozyme providing a population comparable to conventional chromic acid techniques but with the advantage of retained immunogenicity. The staining technique combined indirect immunofluorescence using specific antibodies

Fiona M. K. Corke; C. L. Hedley; P. J. Shaw; T. L. Wang

1987-01-01

296

Variables affecting clinical response to treatment of facial port-wine stains by flash lamp-pumped pulsed dye laser: the importance of looking beyond the skin.  

PubMed

The response of port-wine stains (PWS) to conventional laser treatment in adults is difficult to predict. To assess the influence of local or systemic hemodynamic variables on the clearance of PWS by using flash lamp-pumped pulsed (FLPP) dye laser. All consecutive patients ages 18 years or older undergoing laser treatment for a facial PWS were eligible. Laser sessions were scheduled every 8 weeks. All patients were evaluated based on a standard scale with four evaluation categories, from no or minimal improvement to total or almost total clearance. Clearance was achieved by 50.1 % (95 % confidence interval 35.6-64.7) of patients after a maximum of 15 treatment sessions. In multivariate analysis, increased age, a newly described Type III capillaroscopic pattern, and presence of lesions in dermatome V2 were all associated with a reduced clinical response to treatment. In a model restricted to demographic pattern and patient characteristics, arterial hypertension was also associated with a lower clinical response. A strong association was found between arterial hypertension and the Type III capillaroscopic pattern. Age, arterial hypertension, capillaroscopic pattern, and body location should be considered when planning laser treatment of PWS. PMID:24487956

Bencini, Pier Luca; Cazzaniga, Simone; Galimberti, Michela Gianna; Zane, Cristina; Naldi, Luigi

2014-07-01

297

Monitoring changes in membrane polarity, membrane integrity, and intracellular ion concentrations in Streptococcus pneumoniae using fluorescent dyes.  

PubMed

Membrane depolarization and ion fluxes are events that have been studied extensively in biological systems due to their ability to profoundly impact cellular functions, including energetics and signal transductions. While both fluorescent and electrophysiological methods, including electrode usage and patch-clamping, have been well developed for measuring these events in eukaryotic cells, methodology for measuring similar events in microorganisms have proven more challenging to develop given their small size in combination with the more complex outer surface of bacteria shielding the membrane. During our studies of death-initiation in Streptococcus pneumoniae (pneumococcus), we wanted to elucidate the role of membrane events, including changes in polarity, integrity, and intracellular ion concentrations. Searching the literature, we found that very few studies exist. Other investigators had monitored radioisotope uptake or equilibrium to measure ion fluxes and membrane potential and a limited number of studies, mostly in Gram-negative organisms, had seen some success using carbocyanine or oxonol fluorescent dyes to measure membrane potential, or loading bacteria with cell-permeant acetoxymethyl (AM) ester versions of ion-sensitive fluorescent indicator dyes. We therefore established and optimized protocols for measuring membrane potential, rupture, and ion-transport in the Gram-positive organism S. pneumoniae. We developed protocols using the bis-oxonol dye DiBAC4(3) and the cell-impermeant dye propidium iodide to measure membrane depolarization and rupture, respectively, as well as methods to optimally load the pneumococci with the AM esters of the ratiometric dyes Fura-2, PBFI, and BCECF to detect changes in intracellular concentrations of Ca(2+), K(+), and H(+), respectively, using a fluorescence-detection plate reader. These protocols are the first of their kind for the pneumococcus and the majority of these dyes have not been used in any other bacterial species. Though our protocols have been optimized for S. pneumoniae, we believe these approaches should form an excellent starting-point for similar studies in other bacterial species. PMID:24637356

Clementi, Emily A; Marks, Laura R; Roche-Håkansson, Hazeline; Håkansson, Anders P

2014-01-01

298

Near-Wall Motion of Caged Fluorescent Dye in Microchannel Flows Obtained from Evanescent Wave Molecular Tagging  

NASA Astrophysics Data System (ADS)

A molecular tagging technique utilizing evanescent wave illumination was developed to investigate the motion of a caged fluorescent dye in the vicinity of the microchannel wall surface in electroosmotic and pressure-driven flows. A line pattern in a buffer solution was written by a pulsed UV laser and the uncaged dye was excited by the evanescent wave with total internal reflection inside the glass wall using an objective lens. The velocities calculated by the measured displacement of the near-wall tagged region were compared with the results of molecular tagging using volume illumination, which represents the bulk flow information. Concerning electroosmotic flow, the micro-PIV technique using a confocal microscope system was applied to the microchannel rinsed by the caged fluorescein beforehand in comparison with a pure glass-PDMS microchannel to examine the effect of dye adsorption to the wall on the electroosmotic mobility. The electroosmotic mobility obtained by evanescent wave molecular tagging (EWMT) showed close to the micro-PIV measurement result near the glass wall for the rinsed case and the uncaged dye at the almost constant velocity remained in the depthwise illumination region. On the other hand, the dye velocity in pressure-driven flow by EWMT increased rapidly with respect to time. The uncaged dye convected to the streamwise direction dispersed toward the wall due to the concentration gradient of the dye, which was confirmed by the numerical simulations.

Senga, Yuriko; Nakamura, Tsubasa; Fukumura, Hiroki; Ichiyanagi, Mitsuhisa; Sato, Yohei

299

Conformational dependence of energy transfer rate between photochromic molecule and fluorescent dye  

NASA Astrophysics Data System (ADS)

The dependence of the energy transfer rate from the fluorescent dye, bis(phenylethynyl)anthracene, to the diarylethene derivative on the dihedral angle around the adamantyl spacer, which is used in the single-molecule photoswitching experiment based on the photochromism [T. Fukaminato, T. Sasaki, T. Kawai, N. Tamai, M. Irie, J. Am. Chem. Soc. 126 (2004) 14843], is examined using the ab initio calculations. For the interpretation of the single-molecule photoswitching experiment, most desirable condition is that the on/off of the florescence is directly due to the photochromic reaction, but not others. One of the undesirable factors is the dependence of the energy transfer rate on the dihedral angle around spacer. The computational results show that the energy transfer rate depends little on the dihedral angle.

Yokojima, Satoshi; Ryuo, Koutaro; Tachikawa, Masanori; Kobayashi, Takao; Kanda, Katsuya; Nakamura, Shinichiro; Ebisuzaki, Toshikazu; Fukaminato, Tuyoshi; Irie, Masahiro

2007-12-01

300

Rapid apoplastic pH measurement in Arabidopsis leaves using a fluorescent dye  

PubMed Central

In plants, the extracellular space (apoplast) is one of the main places where exchange of molecules occurs between cells. Not only is this compartment involved in the storage of multiple metabolites and ions, including calcium and protons, but it also plays a role in the transmission of signaling molecules for cell-to-cell communication. It has recently been shown multiple times that these two aspects are linked and can influence each other. In particular, apoplast pH was shown as a primary regulator of auxin (IAA) transport in Arabidopsis thaliana. To prove the role of apoplastic pH, we have developed a protocol for apoplastic fluid extraction from Arabidopsis leaves, followed by pH determination using the 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) fluorescent dye. This technique successfully allows one to monitor apoplastic pH variations among different plant lines and to link changes in apoplastic pH to cellular responses in the plant.

Villiers, Florent; Kwak, June M.

2013-01-01

301

Carboxylate-modified squaraine dye doped silica fluorescent pH nanosensors  

NASA Astrophysics Data System (ADS)

Novel carboxylate-modified fluorescent silica pH nanosensors were synthesized using a reverse microemulsion method with a pH sensitive squaraine dye used as pH indicator. This pH sensitive squaraine dye was simply doped inside SiNPs without any complicated procedures. To avoid aggregation among the particles and to increase the water solubility of the pH nanosensors, the SiNPs were surface modified with a carboxyl group. This pH probe exhibits a good linear dynamic response between pH 3.01 and 5.72. Many alkali, alkaline earth, and transitional metal ions including Li + , Na + , K + , Rb + , Cs + , Mg2 + , Ca2 + , Sr2 + , Al3 + , V5 + , Cr3 + , Cr6 + , Mn2 + , Fe2 + , Fe3 + , Co2 + , Ni3 + , Cu2 + , Zn2 + , As3 + , Se4 + , Mo6 + , Ag + , Cd2 + , La3 + , Er3 + , Ir3 + , Hg + , Hg2 + , and Pb2 + had no significant interference on pH value determination. Artificial sample determination showed that the pH nanosensors developed in this work possess a very promising applicability in biological and biomedical fields.

Xue, Lina; Li, Baiyan; Fei, Qiang; Feng, Guodong; Huan, Yanfu; Shi, Zhan

2010-05-01

302

Metamaterials based on plasmonic nanoshells and loss-compensation using fluorescent dye molecules and quantum dots  

NASA Astrophysics Data System (ADS)

Composite materials based on plasmonic nanoparticles allow building metamaterials with very large effective permittivity (positive or negative) or ?-near-zero moreover, if clustered or combined with other nanoparticles, it is possible to generate also effective magnetic permeability (positive or negative), and an ad-hoc design would result in the generation of double negative materials, and therefore backward wave propagation. However, losses are usually significant and affect the metamaterial performance. In this work, we report on the possibility of adopting fluorescent dye molecules or quantum dots, optically pumped, embedded into the dielectric cores of the employed nanoshell particles, and provide loss-compensation in ordered 3D periodic arrays at optical frequencies. Each spherical nanoshell is modeled as an electric dipole. We consider nanoparticles with gold and silver shells. We then find the modes with complex wavenumber in the metamaterial, and describe the composite material in terms of homogenized effective material parameters (refractive index and permittivity). Furthermore, in case of loss-compensation, we compare the results obtained from modal analysis with the ones computed by using two different homogenization methods: (i) Maxwell Garnett homogenization theory and (ii) Nicholson-Ross-Weir retrieval method. We show the design of two ?-near-zero metamaterials with low losses by simulating gain material made of dyes or quantum dots with realistic parameters. A brief discussion about the employment of the two kinds of active gain materials adopted here is given in the end.

Campione, Salvatore; Capolino, Filippo

2012-02-01

303

Counting fluorescent dye molecules on DNA origami by means of photon statistics.  

PubMed

Obtaining quantitative information about molecular assemblies with high spatial and temporal resolution is a challenging task in fluorescence microscopy. Single-molecule techniques build on the ability to count molecules one by one. Here, a method is presented that extends recent approaches to analyze the statistics of coincidently emitted photons to enable reliable counting of molecules in the range of 1-20. This method does not require photochemistry such as blinking or bleaching. DNA origami structures are labeled with up to 36 dye molecules as a new evaluation tool to characterize this counting by a photon statistics approach. Labeled DNA origami has a well-defined labeling stoichiometry and ensures equal brightness for all dyes incorporated. Bias and precision of the estimating algorithm are determined, along with the minimal acquisition time required for robust estimation. Complexes containing up to 18 molecules can be investigated non-invasively within 150 ms. The method might become a quantifying add-on for confocal microscopes and could be especially powerful in combination with STED/RESOLFT-type microscopy. PMID:23794455

Kurz, Anton; Schmied, Jürgen J; Grußmayer, Kristin S; Holzmeister, Phil; Tinnefeld, Philip; Herten, Dirk-Peter

2013-12-01

304

Time-resolved fluorescence for breast cancer detection using an octreotate-indocyanine green derivative dye conjugate  

NASA Astrophysics Data System (ADS)

Time-resolved fluorescence was used to investigate malignant and normal adjacent breast tissues stained with a conjugate of indocyanine green and octreotate. A marked increase in fluorescence lifetime intensity was seen in the breast cancer sample compared to the normal sample. The fluorescent lifetimes were also investigated and showed similar fluorescence decay curves in stained malignant and normal breast tissue. These results confirm that somatostatin receptors occur on human breast carcinomas, suggest that the presence of somatostatin receptors should be investigated as a marker of breast cancer aggressiveness, and suggest that this conjugate might be used to detect the presence of residual breast cancer after surgery, allowing better assessment of tumor margins and reducing the need for second or repeat biopsies in selected patients. These results may also provide clues for designing future treatment options for breast cancer patients.

Sordillo, Laura A.; Das, B. B.; Pu, Yang; Liang, Kexian; Milione, Giovanni; Sordillo, Peter P.; Achilefu, Sam; Alfano, R. R.

305

Substituent and Solvent Effects on Excited State Charge Transfer Behavior of Highly Fluorescent Dyes Containing Thiophenylimidazole-Based Aldehydes  

NASA Technical Reports Server (NTRS)

The excited state charge transfer for a series of highly fluorescent dyes containing thiophenylimidazole moiety was investigated. These systems follow the Twisted Intramolecular Charge Transfer (TICT) model. Dual fluorescence was observed for each substituted dye. X-ray structures analysis reveals a twisted ground state geometry for the donor substituted aryl on the 4 and 5 position at the imidazole ring. The excited state charge transfer was modeled by a linear solvation energy relationship using Taft's pi and Dimroth's E(sub T)(30) as solvent parameters. There is linear relation between the energy of the fluorescence transition and solvent polarity. The degree of stabilization of the excited state charge transfer was found to be consistent with the intramolecular molecular charge transfer. Excited dipole moment was studied by utilizing the solvatochromic shift method.

Santos, Javier; Bu, Xiu R.; Mintz, Eric A.

2001-01-01

306

Bright red organic light-emitting diodes doped with a fluorescent dye  

NASA Astrophysics Data System (ADS)

We have evaluated a synthetic red fluorescent dye, 6-methyl-3-[3-(1,1,6,6-tetramethyl-10-oxo2,3,5,6-tetrahydro-1H,4H,10H-11 -oxa-3a-aza-benzo[de]anthracen-9-yl)-acryloyl]-pyran-2,4-dione (AAAP), as a dopant for an organic light-emitting diode (LED). Bright emission of a good red (maximum luminance: 5600 cd/m2, chromaticity coordinates: x=0.63, y=0.36) was obtained. The device consisted of ITO/TPD(50 nm)/Alq3 doped with AAAP(1.5 mol %,15 nm)/bOXDF(20 nm)/Alq3(25 nm)/Mg:Ag (ITO: indium tin oxide, TPD: N, N'-diphenyl- N,N'-di(3-methylphenyl)-1, 1'biphenyl-4,4'-diamine, Alq3: tris (8-hydroxyquinolinato)-aluminum (III), bOXDF:2,2-bis[5-(4-biphenyl)-1,3,4-oxadiazole-2-yl-4,1 -phenylene]-hexafluoropropane). The bands of fluorescence of the Alq3 host and of absorption of the AAAP dopant overlap in an advantageous way, and insertion of the bOXDF layer between the emission layer, doped with AAAP, and Alq3 layer, made for a device with good properties.

Mitsuya, Masayuki; Suzuki, Takayuki; Koyama, Toshiki; Shirai, Hirofusa; Taniguchi, Yoshio; Satsuki, Makoto; Suga, Sadaharu

2000-11-01

307

Fluorescent dye-labelled polymer synthesis by nitroxide mediated radical polymerization  

NASA Astrophysics Data System (ADS)

New applications of polymers at advanced technologies demand increased requirements on their properties. These properties are influenced by molecular as well as supramolecular structure. Controlled radical polymerization mediated by stable nitroxides (NMP) or substituted alkoxyamines offers simple method for preparation of polymers with programmable structure of macromolecules which possess remarkable better physical as well as chemical properties. They can be used as a macro initiators for the synthesis of block copolymers. At the present time it has been generally accepted that the extent of "livingness" is high for all conversions [1-4]. To verify this statement a series of fluorescent dye-labelled regulators has been synthesized, spectrally characterized and used as the mediators of styrene and n-butyl acrylate polymerization. Direct quantification of dormant species concentration (extent of livingness) and calculation of molar mass of marked polymers was performed by absorption and/or emission spectroscopy. Controlled radical polymerization mediated by stable nitroxides bearing fluorescence mark represents unconventional approach for monitoring and evaluation of mechanism and kinetics of polymerization process. Results indicate that the extent of livingness is strongly influenced by conversion as well as mediator concentration. There is a clear tendency toward to decreasing amount of dormant species with increasing monomer conversion. Moreover, lower mediator concentration decreases livingness of polymerization process.

Kollár, Jozef; Chmela, Štefan; Hr?ková, ?udmila; Hrdlovi?, Pavol

2012-07-01

308

[Nonsymmetrical polymethine dyes as fluorescent probes for the study of microviscosity of membrane phospholipid bilayers].  

PubMed

Nonsymmetrical polymethine dyes are shown to be applied as a new approach in the studies of phospholipid membrane microviscosity. The method requires determination of the intensity ratio for the long-wave length (Ig) and short-wave length (Ik) bands of fluorescence spectra in the region of 730-770 nm at exitation 600 nm. It allows determination of microviscosity by comparative measurements of the fluorescence parameter Ig/Ik in the model medium of the known viscosity (glycerol) and the object under study. Microviscosity in egg phosphatidylcholine vesicules (liposomes) is found to be 0.6-1.2 P. It depends on the surface curvature (size of vesicle), cholesterol content and temperature. It the studies of dimiristoylphosphatidyl choline liposomes the changes in microviscosity at the phase transition temperature are shown to be from 4.5 to 1.1 P. The transition temperature is 24.5 degrees C, the transition range being 2.2 degrees C. The results of this work demonstrate the advantages of the suggested approach to study mobility in phospholipid membranes and confirm it to be promising to study natural membranes and whole cells. PMID:3413843

Volovik, Z N; Demchenko, A P; Ishchenko, A A; Slominski?, Iu L; Tolmachev, A I

1988-01-01

309

Energy migration toward a dye in nanoparticles from complexes with short fluorescent state lifetimes  

NASA Astrophysics Data System (ADS)

We have studied regular features of the fluorescence sensitization (cofluorescence) of coumarin 30 and rhodamine 6G introduced into nanoparticles from complexes Ln(PhBTA)3phen, where PhBTA is p-phenylbenzoyltrifluoroacetone and Ln is a triply charged Pr, Nd, Sm, Eu, Er, or Yb ion, which absorbs in the fluorescence range of ligands of complexes and dyes. We show that both the cofluorescence intensities ( I cofl) of rhodamine 6G in nanoparticles from Sm and Eu complexes and the behavior of intensity I cofl on the content of rhodamine 6G coincide with the corresponding data obtained for nanoparticles from La and Lu complexes doped with rhodamine 6G molecules. A considerable decrease in I cofl of rhodamine 6G is observed only in nanoparticles from complexes Nd(PhBTA)3phen. In nanoparticles from Pr, Nd, Sm, Eu, Er, and Yb complexes doped with coumarin 30, it has been observed that, depending on the choice of the central ion, I cofl of coumarin 30 is 2 to 80 times lower compared to I cofl of the dye in nanoparticles from La and Lu complexes. A separate analysis of the influence of these ions on the energy transfer from complexes to coumarin 30 and on the fluorescence intensity of coumarin 30 incorporated into nanoparticles from these ions showed that a decrease in I cofl of coumarin 30 by a factor of 2-20 occurs due to the reduction of ?fl of ligands of complexes under the influence of the interaction with Pr, Nd, Sm, Eu, Er, and Yb ions. Since ?fl of complexes La(PhBTA)3phen is ˜2 ps, while that of complexes Gd(PhBTA)3phen is ˜1 ps, then, in nanoparticles with a maximal decrease in I cofl of coumarin 30, ?fl of complexes is reduced to ˜0.1 ps. It has been found that, in nanoparticles from complexes with this ?fl, energy migration over complexes takes place. However, as distinct from nanoparticles from La, Lu, and Y complexes, the free path length of singlet excitons in nanoparticles from complexes of absorbing ions is smaller than the nanoparticle size.

Sveshnikova, E. B.; Mironov, L. Yu.; Dudar', S. S.; Ermolaev, V. L.

2012-12-01

310

Ultra Q-bodies: quench-based antibody probes that utilize dye-dye interactions with enhanced antigen-dependent fluorescence  

PubMed Central

Recently, we described a novel reagentless fluorescent biosensor strategy named Quenchbody, which functions via the antigen-dependent removal of the quenching effect on a fluorophore that is attached to a single-chain antibody variable region. To explore the practical utility of Quenchbodies, we prepared antibody Fab fragments that were fluorolabeled at either one or two of the N-terminal regions, using a cell-free translation-mediated position-specific protein labeling system. Unexpectedly, the Fab fragment labeled at the heavy chain N-terminal region demonstrated a deeper quenching and antigen-dependent release compared to that observed using scFv. Moreover, when the Fab was fluorolabeled at the two N-termini with either the same dye or with two different dyes, an improved response due to enhanced quenching via dye-dye interactions was observed. On the basis of this approach, several targets, including peptides, proteins, and haptens, as well as narcotics, were quantified with a higher response up to 50-fold. In addition, differentiation of osteosarcoma to osteoblasts was successfully imaged using a similarly fluorolabeled recombinant Fab protein prepared from E. coli. Due to its versatility, this “Ultra-Quenchbody” is expected to exhibit a range of applications from in vitro diagnostics to the live imaging of various targets in situ.

Abe, Ryoji; Jeong, Hee-Jin; Arakawa, Dai; Dong, Jinhua; Ohashi, Hiroyuki; Kaigome, Rena; Saiki, Fujio; Yamane, Kyosuke; Takagi, Hiroaki; Ueda, Hiroshi

2014-01-01

311

Rapid visualization of viable and nonviable endothelium on cardiovascular prosthetic surfaces by means of fluorescent dyes.  

PubMed

Increasing interest in endothelialization of synthetic and tissue cardiovascular prostheses in vitro emphasizes the need for simple and rapid methods to evaluate presence of endothelium on surfaces. Scanning electron microscopy is a commonly used method for this purpose. In this study we investigated alternative and more rapid staining methods. Human saphenous vein endothelial cells in culture and on cardiovascular prosthetic materials (pyrolytic carbon, cusps of bioprosthetic heart valves, pig aorta, and expanded polytetrafluoroethylene) were labeled by exposing them to medium containing 5-chloromethylfluorescein diacetate or 1,1-dioctadecyl-3,3,3',3'-tetramethylindo carbocyanine perchlorate. For comparison, specimens were also fixed and processed for scanning electron microscopy. A bright fluorescence of endothelial cells labeled with 5-chlormethylfluorescein diacetate or 1,1-deoctadecyl-3,3,3',3'-tetramethylindo carbocyanine perchlorate wre clearly visualized in culture, on pyrolytic carbon, and on expanded polytetrafluoroethylene. Unfixed, prelabeled cells could be visualized immediately and unlabeled cells could be investigated for viability within 1 hour. Cells seeded on biologic tissue specimens could be visualized within 15 minutes with a modified hematoxylin-eosin staining. We suggest the use of these methods for rapid visualization of endothelium present on surfaces of cardiovascular prosthetic materials where they can partly replace the use of scanning electron microscopy. PMID:7527111

Gillis, C; Haegerstrand, A; Ragnarson, B; Bengtsson, L

1994-12-01

312

Single-Photon Source for Quantum Information Based on Single Dye Molecule Fluorescence in Liquid Crystal Host  

SciTech Connect

This paper describes a new application for liquid crystals: quantum information technology. A deterministically polarized single-photon source that efficiently produces photons exhibiting antibunching is a pivotal hardware element in absolutely secure quantum communication. Planar-aligned nematic liquid crystal hosts deterministically align the single dye molecules which produce deterministically polarized single (antibunched) photons. In addition, 1-D photonic bandgap cholesteric liquid crystals will increase single-photon source efficiency. The experiments and challenges in the observation of deterministically polarized fluorescence from single dye molecules in planar-aligned glassy nematic-liquid-crystal oligomer as well as photon antibunching in glassy cholesteric oligomer are described for the first time.

Lukishova, S.G.; Knox, R.P.; Freivald, P.; McNamara, A.; Boyd, R.W.; Stroud, Jr., C.R.; Schmid, A.W.; Marshall, K.L.

2006-08-18

313

Anisotropic fluorescence emission of a dye-doped fibre ring that is pumped by a ring laser beam  

NASA Astrophysics Data System (ADS)

The fluorescence characteristics of a dye-doped polymer fibre were studied by exciting the fibre ring with a ring laser beam. An efficient excitation was achieved from the fibre side owing to the high absorbance of the organic dye. The pump-laser power could be raised to over 400 kW (pulse duration: 5 ns), which was unattainable by the conventional fibre-end pumping method because of the poor laser power durability of the dye-doped polymers. The fibre ends, which were polished obliquely (45°) to pick up the circulating fluorescence, were coupled to each other with an index-matching oil. When the pump power density exceeded 0.2 kW mm-2 (total power: 40 kW), the circulating beam exhibited both a nonlinear peak-growth and a spectral narrowing that were caused by the stimulated emission. By contrast, the fluorescence in the radial direction became weaker as the pump power increased, indicating that the stimulated emission in the axial direction suppressed the fluorescence in the radial direction.

Saito, M.; Ishiguro, H.

2006-02-01

314

Oxidative synthesis of highly fluorescent boron/nitrogen co-doped carbon nanodots enabling detection of photosensitizer and carcinogenic dye.  

PubMed

Current research efforts have demonstrated the facile hydrothermal oxidative synthetic route to develop highly fluorescent boron/nitrogen co-doped carbon nanodots (CNDs). During this process, N-(4-hydroxyphenyl)glycine served as a source of N doping and a carbon precursor as well, while boric acid H3BO3 is used as an oxidizing agent in the N2 environment. Surface passivation through ultrasonic treatment of CNDs was performed to induce modifications by using various surface passivating agents. Polyethyleneimine (PEI) remarkably enhanced the fluorescence performance and monodispersity of polymerized carbon nanodots (P-CNDs) in aqueous phase with an enhanced quantum yield of 23.71%, along with an increase in size from ~3 nm to ~200 nm. For characterization of CNDs and P-CNDs, UV, infrared, photoluminescence, transmission electron microscopy, x-ray photoelectron spectra, and atomic force microscopy techniques were utilized. Application potentials of synthesized P-CNDs were developed via introduction of protoporphyrin (PPD, a photosensitizer) which has great doping affinity with polymer PEI to switch-off the fluorescence of P-CNDs, leading to the production of dye-doped nanoprobes. Fluorescence resonance energy transfer (FRET) was also observed during dye-doping, and PPD was detected with a limit of detection (LOD, 3?) of 15 pM. The fluorescence recovery of this switched-off nanoprobe was made possible by using Sudan red III (carcinogenic dye), which was oxidized by PPD doped in P-CNDs. Sudan red III was detected in the concentration range of 9.9 pM-0.37 nM. Meanwhile, it was also confirmed that the dye-doped nanoprobe is highly selective and exceptionally sensitive to detect this carcinogenic agent in commercial products with a LOD (3?) of 90 fM. PMID:24083490

Jahan, Shanaz; Mansoor, Farrukh; Naz, Shagufta; Lei, Jianping; Kanwal, Shamsa

2013-11-01

315

Acid-fast stain  

MedlinePLUS

... The slide is then washed with an acid solution and a different stain is applied. Bacteria that hold onto the first dye are considered "acid-fast" because they resist the acid wash. This type of bacteria is associated with tuberculosis and other infections.

316

Strong fluorescence emissions by H-aggregates of the dye thiacyanine in the presence of the surfactant aerosol-OT  

NASA Astrophysics Data System (ADS)

The cationic dye 3,3 '-diethylthiacyanine iodide (THIA) in dilute aqueous solution shows weak fluorescence with a broad peak around 470 nm, and the anionic surfactant bis(2-ethylhexyl) sodium sulphosuccinate, called aerosol-OT (AOT) enhances the fluorescence of the dye. When excited at 422 nm ( ?max of THIA), the fluorescence peak of THIA, in the presence of increasing AOT concentrations up to its critical micellar concentration (CMC), is gradually reduced to a shoulder around 475 nm, and two additional sharp peaks at 494 and 601 nm are progressively developed. Above the CMC of AOT, the original 470 nm peak starts reappearing with simultaneous disappearance of the 494 and 601 nm peaks. At appropriate AOT concentrations (below CMC), THIA forms two metachromatic species (H-aggregates) showing strong absorption peaks at 377 and 366 nm. When excited at these metachromatic peaks, the fluorescence of the THIA/AOT system is, instead of being quenched, largely enhanced about 8-10 times compared to when excited at 422 nm, and above the CMC, fluorescence diminishes. Application of the principal component analysis method to the observed fluorescence spectra results in three pure component spectra with peaks at 470, 494 and 601 nm, which have been assigned to monomer, normal H-aggregates and twisted H-aggregates emission peaks, respectively. The twisted H-aggregates originate from the excited preexisting hexamer as well as from the excimer formed between excited and ground state trimers.

Mandal, Anil Kumar; Pal, Medini Kanta

2000-02-01

317

Potential-modulated fluorescence spectroscopy of zwitterionic and dicationic membrane-potential-sensitive dyes at the 1,2-dichloroethane/water interface.  

PubMed

The previously introduced technique of potential-modulated fluorescence (PMF) spectroscopy was used to study the potential-induced fluorescence change of some different dyes at the polarized 1,2-dichloroethane (DCE)/water (W) interface. A zwitterionic dye (POLARIC 488PPS) showed a PMF response similar to that for the previously studied dye (di-4-ANEPPS) with the same ionic state, and the PMF response was likewise explained by the potential-dependent reorientation of the dye at the DCE/W interface. Though a monocationic dye (POLARIC 488PM) showed no distinct PMF signal, a dicationic dye (di-2-ANEPEQ) showed two relatively weak but detectable PMF signals at lower and higher potential. It has thus been found that the ionic state of a potential-sensitive dye strongly influences the potential-induced reorientation of the dye at the interface and consequently its PMF response. These results support the reorientation/solvatochromic mechanism proposed for "slow" dyes but do not necessarily exclude the electrochromic mechanism proposed for "fast" dyes. PMF spectroscopy would provide useful information on the design of slow dyes for the measurement of the resting potential of cell membranes. PMID:22744747

Osakai, Toshiyuki; Yoshimura, Tatsuya; Kaneko, Daichi; Nagatani, Hirohisa; Son, Sang-Hyun; Yamagishi, Yutaka; Yamada, Koji

2012-08-01

318

Kinetics of White Blood Cell Staining by Intravascular Administration of Rhodamine 6G  

Microsoft Academic Search

Rhodamine 6G is a vital dye accumulating in the mitochondria of cells. It is used in intravital fluorescence microscopy for contrast enhancement of white blood cells (WBC), enabling visualization of WBC in the microvasculature even at high center flow velocity. The aim of this study was to examine the kinetics of WBC staining after intravascular administration of rhodamine 6G in

H. Baatz; M. Steinbauer; A. G. Harris; F. Krombach

1995-01-01

319

Use of DNA stains in immunophenotyping by slide-based cytometry  

NASA Astrophysics Data System (ADS)

Immunophenotyping of peripheral blood leukocytes (PBL) is a very well documented application of Slide Based Cytometry (SBC). As for any other assay it is of highest importance to ensure that all cells which are relevant for an analysis are recognized. Unlike assays for cultured cells which have homogenous morphology immunophenotyping of PBLs is performed on cells with heterogeneous size and shape. Therefore, triggering on parameters related to cell morphology might lead to an incomplete analysis of just a subset of cells especially in pathological conditions. Several dyes stain DNA specifically in a wide variety of emission spectra. Many of them show some influence of the chromatin condensation and organization on the staining intensity. DNA dyes therefore can be used to differentiate between cell types having the same ploidy. This can be exploited for immunophenotyping since some dyes therefore can partially replace antibody staining. The concept of using DNA dyes in the setting of immunostaining has the following advantages: (1) nuclear staining provides a stable and easy triggering signal that guarantees both, that neither cells are excluded nor that debris or polluting particles are included into the analysis; (2) some DNA dyes differentiate between mononuclear and polymorphonuclear cells. A disadvantage of DNA dyes is that mostly cells have to be permeabilized. Because of this only one set of immunophenotypic markers can be stained, cells are fixed and permeabilized, and then nuclei are stained with the appropriate DNA dye. In the study we demonstrate the use of the most commonly available DNA dyes (7-AAD, To-Pro, To-To, PI etc.) in their applicability in immunophenotyping. An overview of spectral properties, fluorescence spill-over and optimal combinations with surface antigen staining will be shown. As in general for SBC only very small sample volumes are needed. This allows to serially analyze PBL in clinical settings that up to now could not be studied in detail such as in the critical ill patient, during major surgery, and in new-borns and infants.

Gerstner, Andreas O. H.; Laffers, Wiebke; Bootz, Friedrich; Tárnok, Attila

2003-06-01

320

Comparative sensitivity of fluorescent antibody staining of conjunctival scrapings and irradiated McCoy cell culture for the diagnosis of hyperendemic trachoma.  

PubMed

The sensitivity of an indirect fluorescent antibody (FA) staining technique for detecting chlamydial inclusions in scrapings from the whole conjunctiva (upper tarsus, upper fornix, and lower lid) was compared with the sensitivity of culture in irradiated McCoy cells for the diagnosis of hyperendemic trachoma. In a group of 211 patients with various grades of active trachoma from the Bandar Abbas area of Southern Iran 42 patients were positive for chlamydiae by either method. There was little difference between the rates of positivity of FA staining of the scrapings from the whole conjunctiva (28 positives) and culture in irradiated McCoy cells (32 positives). In the patients included in this study chlamydial inclusions were detected in 15 eyes by examination of FA stained scrapings taken from the upper tarsal conjunctiva, whereas inclusions were detected in 40 eyes by the additional examination of scrapings taken from the upper fornix and lower lid (P less than 0.001). The examination of FA stained scrapings taken from the whole conjunctiva and spread as a single but larger smear may provide a satisfactory alternative to cell culture methods for the diagnosis of trachoma, particularly for field studies when cell culture facilities are not available. PMID:6992855

Darougar, S; Woodland, R M; Jones, B R; Houshmand, A; Farahmandian, H A

1980-04-01

321

Synthesis and application of 2-styryl-6(7)-bromothiazolo[4,5-b]quinoxaline based fluorescent dye chromophores: Part 2  

Microsoft Academic Search

A novel efficient synthesis of 2-styryl-6(7)-bromothiazolo[4,5-b]quinoxaline based fluorescent dyes was achieved by the condensation of 2-alkyl-6(7)-bromothiazolo[4,5-b]quinoxaline with selected 4-N,N-dialkylamino-substituted arylaldehydes and heteroarylaldehydes in the presence of piperidine or acid anhydride. The colouristic, fluorophoric, and dyeing properties of these dyes were studied.

D. W. Rangnekar; N. D. Sonawane

2000-01-01

322

Ethidium bromide: a fast fluorescent staining procedure for the detection of symbiotic partnership of flagellates and prokaryotes  

Microsoft Academic Search

The hindgut of ‘lower’ termites harbors a dense population of flagellates and bacteria. The flagellates possess ecto- and endosymbiotic prokaryotes. Most of them are hardly visible in the phase contrast microscope. Staining with the DNA-intercalating agent ethidium bromide visualizes the nuclei of the flagellates as well as the ecto- and endosymbiotic bacteria as red objects. Furthermore, it is possible to

1999-01-01

323

Dieldrin Inhibition of Gap Junctional Intercellular Communication in Rat Glial Cells as Measured by the Fluorescence Photobleaching and Scrape Loading/Dye Transfer Assays,  

National Technical Information Service (NTIS)

Application of the fluorescence-recovery after photobleaching (FRAP analysis) technique and scrape loading/dye transfer assay was made to measure the presence of gap junctional communication in primary rat glial cells in vitro in the presence and absence ...

J. E. Trosko M. H. El-Fouly S. Suter L. R. Lockwood A. Koestner

1987-01-01

324

Theoretical investigation on saturated Förster-Resonant-Energy-Transfer Microscopy using FRET dye pairs as fluorescent probes  

NASA Astrophysics Data System (ADS)

Saturated Förster-Resonant-Energy-Transfer (FRET) microscopy (SFM) employing tiny silica nanoparticles densely co-doped with Cy3 and Cy5 molecules as fluorescent labels has been proposed and analyzed with rigorous rate equations previously, showing that optical resolutions beyond the diffraction-limit in both lateral and axial directions can be realized by exploiting the saturation effect in FRET process. Here, using a set of similar rate equations, we show that SFM can also be realized with single FRET dye pairs as fluorescent labels. A similar nonlinear optical response to excitation beam is revealed for Cy3-Cy5 dye pairs, in comparison to the silica nanoparticles co-doped with Cy3 and Cy5 molecules.

Chen, Jianfang; Cheng, Ya

2012-03-01

325

Bioconjugatable azo-based dark-quencher dyes: synthesis and application to protease-activatable far-red fluorescent probes.  

PubMed

We describe the efficient synthesis and one-step derivatization of novel, nonfluorescent azo dyes based on the Black Hole Quencher-3 (BHQ-3) scaffold. These dyes were equipped with various reactive and/or bioconjugatable groups (azido, ?-iodoacetyl, ketone, terminal alkyne, vicinal diol). The azido derivative was found to be highly reactive in the context of copper-catalyzed azide-alkyne cycloaddition (CuAAC) reactions and allowed easy synthetic access to the first water-soluble (sulfonated derivative) and aldehyde-modified BHQ-3 dyes, the direct preparation of which failed by means of conventional azo-coupling reactions. The aldehyde- and ?-iodoacetyl-containing fluorescence quenchers were readily conjugated to aminooxy- and cysteine-containing peptides by the formation of a stable oxime or thioether linkage, respectively. Further fluorescent labeling of the resultant peptide conjugates with red- or far-red-emitting rhodamine or cyanine dyes through sequential and/or one-pot bioconjugations, led to novel Förster resonance energy transfer (FRET) based probes suitable for the in vivo detection and imaging of urokinase plasminogen activator, a key protease in cancer invasion and metastasis. PMID:23255474

Chevalier, Arnaud; Massif, Cédrik; Renard, Pierre-Yves; Romieu, Anthony

2013-01-28

326

Excitation laser energy dependence of surface-enhanced fluorescence showing plasmon-induced ultrafast electronic dynamics in dye molecules  

NASA Astrophysics Data System (ADS)

We find unique properties accompanying surface-enhanced fluorescence (SEF) from dye molecules adsorbed on Ag nanoparticle aggregates, which generate surface-enhanced Raman scattering. The properties are observed in excitation laser energy dependence of SEF after excluding plasmonic spectral modulation in SEF. The unique properties are large blue shifts of fluorescence spectra, deviation of ratios between anti-Stokes SEF intensity and Stokes from those of normal fluorescence, super-broadening of Stokes spectra, and returning to original fluorescence by lower energy excitation. We elucidate that these properties are induced by electromagnetic enhancement of radiative decay rates exceeding the vibrational relaxation rates within an electronic excited state, which suggests that molecular electronic dynamics in strong plasmonic fields can be largely deviated from that in free space.

Itoh, Tamitake; Yamamoto, Yuko S.; Tamaru, Hiroharu; Biju, Vasudevanpillai; Murase, Norio; Ozaki, Yukihiro

2013-06-01

327

Calmodulin Activation of the Ca 2+ Pump Revealed by Fluorescent Chelator Dyes in Human Red Blood Cell Ghosts  

Microsoft Academic Search

Ca 2+ transport in red blood cell ghosts was monitored with fura2 or quin2 incorporated as the free acid during resealing. This is the first report of active transport monitored by the fluorescent intensity of the chelator dyes fura2 (5-50 ~M) or quin2 (250 ~M) in hemoglobin-depleted ghosts. Since there are no intracellular compartments in ghosts and the intracellular concentrations

MARILYN R. JAMES-KRACKE

1992-01-01

328

FLUORESCENCE RESONANCE ENERGY TRANSFER DYE NUCLEOTIDE TERMINATORS: A NEW SYNTHETIC APPROACH FOR HIGH-THROUGHOUT DNA SEQUENCING  

Microsoft Academic Search

Fluorescence resonance energy transfer (FRET) based dye-nucleotide terminators (10–13) were designed, synthesized, and formulated with Thermo Sequenase™ II DNA polymerase into a robust kit for high throughput DNA sequencing. The key energy transfer (ET) rigid and linear linker (2), required for the syntheses of energy transfer cassettes (6–9) was synthesized via Heck coupling reaction on t-Boc-L-4-iodo-phenylalanine (1) with N-TFA-propargylamine.

Satyam Nampalli; Mahesh Khot; John R. Nelson; Parke K. Flick; Carl W. Fuller; Shiv Kumar

2001-01-01

329

Sensitive Spectroscopic Detection of Large and Denatured Protein Aggregates in Solution by Use of the Fluorescent Dye Nile Red  

Microsoft Academic Search

The fluorescent dye Nile red was used as a probe for the sensitive detection of large, denatured aggregates of the model protein\\u000a ?-galactosidase (E. coli) in solution. Aggregates were formed by irreversible heat denaturation of ?-galactosidase below and above the protein’s unfolding\\u000a temperature of 57.4°C, and the presence of aggregates in heated solutions was confirmed by static light scattering. Interaction

Marc Sutter; Sabrina Oliveira; Niek N. Sanders; Bart Lucas; Arie van Hoek; Mark A. Hink; Antonie J. W. G. Visser; Stefaan C. De Smedt; Wim E. Hennink; Wim Jiskoot

2007-01-01

330

Structurally Rigid 2,6-distyrylpyridines—A New Class of Fluorescent Dyes. 1. Synthesis, Steric Constitution and Spectral Properties  

Microsoft Academic Search

A group of structurally rigid analogues of 2,6-distyrylpyridine was synthesised. Molecular geometry of the synthesised dyes in solutions was studied by 1H-NMR, electronic absorption and fluorescence spectrometry. The spectral data testify all the compounds exist in E-configuration of their styryl residues. The most planar molecular conformation is typical for the compounds with five-membered side aromatic moieties. In the case of

V. G. Pivovarenko; A. V. Grygorovych; V. F. Valuk; A. O. Doroshenko

2003-01-01

331

Photodetection of early cancer by laser-induced fluorescence of a tumor-selective dye: apparatus design and realization  

NASA Astrophysics Data System (ADS)

An apparatus is designed and realized to detect "early" cancer at the surface of the hollow organs in the human body by endoscopic means. The tumor is localized by the laser induced fluorescence of a dye (HPD) which concentrates selectively in the neoplastic tissue after intravenous injection. Fluorescence contrast between the tumor and its normal surroundings is enhanced by subtracting the background autofluorescence which occurs in both types of tissue. This is done by means of 2-color digital images manipulation in real-time. Preliminary clinical tests of the apparatus demonstrated the detection of carcinoma in situ in the esophagus.

Wagnieres, Georges A.; Depeursinge, Christian D.; Monnier, Philippe; Savary, Jean-Francois; Cornaz, Piet F.; Chatelain, Andre; van den Bergh, Hubert

1990-07-01

332

In vivo fluorescence microscopy of neuronal activity in three dimensions by use of voltage-sensitive dyes  

NASA Astrophysics Data System (ADS)

We report in vivo imaging of neuronal electrical activity from superficial layers of the mouse barrel cortex. The measurements have ~16-?m spatial and 3-ms temporal resolution and reach depths of 150 ?m below the cortical surface. The depth-dependent differential-fluorescence optical sections of activity are consistent with known cortical architecture and represent an important step toward in vivo measurement of functioning complex neural networks. Our observations employ a custom gradient-index lens probe and voltage-sensitive dye fluorescence; the use of epi-illumination rather than dark-field illumination provides the dramatic signal-to-noise improvement necessary for fast three-dimensional imaging.

Fisher, Jonathan A. N.; Civillico, Eugene F.; Contreras, Diego; Yodh, Arjun G.

2004-01-01

333

Ionic comonomer effect of poly(N-isopropylacrylamide) copolymer containing D-?-A type pyran-based fluorescent dye  

NASA Astrophysics Data System (ADS)

Temperature and pH responsive poly(N-isopropylacrylamide) (poly(NIPAM)) copolymer containing D-?-A type pyran-based fluorescent dye (fluorophore) and basic comonomer, N-[3-(dimethylamino)propyl]-methacrylamide (DMAPAM) was prepared by free radical polymerization. With increase of pH values, aqueous poly(NIPAM-co-DMAPAM-co-fluorophore) solution showed decrease of a lower critical solution temperature (LCST) and increase of fluorescence intensity, due to a change in the ionization state. And also hydrodynamic radius of poly(NIPAM-co-DMAPAM-co-fluorophore) changed correspondingly to changes of temperature and pH values.

Lee, Eun-Mi; Gwon, Seon-Young; Hwang, In-Jeong; Son, Young-A.; Kim, Sung-Hoon

2012-06-01

334

Enhanced Fluorescence of Quantum Dots by Au Nanoparticles on MultiColor Silica Spheres Labeled with Organic Dyes and Quantum Dots  

Microsoft Academic Search

We have prepared the multi-color hybrid silica spheres by assembling CdSe\\/ZnS quantum dots (QDs) on the organic dye-doped silica spheres. The labeled silica spheres can be excited simultaneously and exhibit dual luminescent emissions corresponding to the dyes and QDs, respectively. The fluorescence of QDs can be selective enhanced by Au nanoparticles, and the fluorescence intensity ratio of the dual emissions

Xian Zhang; Min Li; Xiao-Niu Peng; Li Zhou

2009-01-01

335

Part-per-trillion level detection of estradiol by competitive fluorescence immunoassay using DNA\\/dye conjugate as antibody multiple labels  

Microsoft Academic Search

Fluorescent organic dyes are currently the standard signal-generating labels used in microarray quantification. However, new labeling strategies are needed to meet the demand for high sensitivity in the detection of low-abundance proteins and small molecules. In this report, a long-chain DNA\\/dye conjugate was used to attach multiple fluorescence labels on antibodies to improve signal intensity and immunoassay sensitivity. Compared with

Shengchao Zhu; Qin Zhang; Liang-Hong Guo

2008-01-01

336

Fluorescence lifetime imaging microscope consisting of a compact picosecond dye laser and a gated charge-coupled device camera for applications to living cells.  

PubMed

An inverted microscope was combined with a compact dye laser with a pulse width of <190 ps and an intensified charge-coupled device (ICCD) camera with a minimum gate width of 200 ps. The resulting fluorescence lifetime imaging microscope, which has a temporal resolution of 340 ps, was used to measure the fluorescence lifetime of polymer microspherers. The results indicated a fluorescence lifetime of 0.9 ns. The present analytical instrument was also employed in an evaluation of biological cells after labeling them with SYTO 13, a fluorescent dye. PMID:17038764

Uchimura, Tomohiro; Kawanabe, Satoshi; Maeda, Yuki; Imasaka, Totaro

2006-10-01

337

Rapid apoplastic pH measurement in Arabidopsis leaves using a fluorescent dye.  

PubMed

In plants, the extracellular space (apoplast) is one of the main places where exchange of molecules occurs between cells. Not only is this compartment involved in the storage of multiple metabolites and ions, including calcium and protons, but it also plays a role in the transmission of signaling molecules for cell-to-cell communication. It has recently been shown multiple times that these two aspects are linked and can influence each other. In particular, apoplast pH was shown as a primary regulator of auxin (IAA) transport in Arabidopsis thaliana. To prove the role of apoplastic pH, we have developed a protocol for apoplastic fluid extraction from Arabidopsis leaves, followed by pH determination using the 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) fluorescent dye. This technique successfully allows one to monitor apoplastic pH variations among different plant lines and to link changes in apoplastic pH to cellular responses in the plant. PMID:23221761

Villiers, Florent; Kwak, June M

2013-01-01

338

Volume labeling with Alexa Fluor dyes and surface functionalization of highly sensitive fluorescent silica (SiO2) nanoparticles  

NASA Astrophysics Data System (ADS)

A new synthesis approach is described that allows the direct incorporation of fluorescent labels into the volume or body of SiO2 nanoparticles. In this process, fluorescent Alexa Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and a polydispersity of <15%. In comparison with conventional surface tagged particles created by post-synthesis modification, this process maintains the physical and surface chemical properties that have the most pronounced effect on colloidal stability and interactions with their surroundings. These volume-labeled nanoparticles have proven to be extremely robust, showing excellent signal strength, negligible photobleaching, and minimal loss of functional organic components. The native or ``free'' surface of the volume-labeled particles can be altered to achieve a specific surface functionality without altering fluorescence. Their utility was demonstrated for visualizing the association of surface-modified fluorescent particles with cultured macrophages. Differences in particle agglomeration and cell association were clearly associated with differences in observed nanoparticle toxicity. The capacity to maintain particle fluorescence while making significant changes to surface chemistry makes these particles extremely versatile and useful for studies of particle agglomeration, uptake, and transport in environmental and biological systems.A new synthesis approach is described that allows the direct incorporation of fluorescent labels into the volume or body of SiO2 nanoparticles. In this process, fluorescent Alexa Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and a polydispersity of <15%. In comparison with conventional surface tagged particles created by post-synthesis modification, this process maintains the physical and surface chemical properties that have the most pronounced effect on colloidal stability and interactions with their surroundings. These volume-labeled nanoparticles have proven to be extremely robust, showing excellent signal strength, negligible photobleaching, and minimal loss of functional organic components. The native or ``free'' surface of the volume-labeled particles can be altered to achieve a specific surface functionality without altering fluorescence. Their utility was demonstrated for visualizing the association of surface-modified fluorescent particles with cultured macrophages. Differences in particle agglomeration and cell association were clearly associated with differences in observed nanoparticle toxicity. The capacity to maintain particle fluorescence while making significant changes to surface chemistry makes these particles extremely versatile and useful for studies of particle agglomeration, uptake, and transport in environmental and biological systems. Electronic supplementary information (ESI) available: Cell culture preparation for dose/response imaging experiments. See DOI: 10.1039/c3nr02639f

Wang, Wei; Nallathamby, Prakash D.; Foster, Carmen M.; Morrell-Falvey, Jennifer L.; Mortensen, Ninell P.; Doktycz, Mitchel J.; Gu, Baohua; Retterer, Scott T.

2013-10-01

339

Volume Labeling with Alexa-Fluor Dyes and Surface Functionalization of Highly Sensitive Fluorescent SiO2 Nanoparticles  

SciTech Connect

A new synthesis approach is described that allows the direct incorporation of fluorescent labels into the volume or body of SiO2 nanoparticles. In this process, fluorescent Alexa Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and a polydispersity of <15%. In comparison with conventional surface tagged particles created by post-synthesis modification, this process maintains the physical and surface chemical properties that have the most pronounced effect on colloidal stability and interactions with their surroundings. These volume-labeled nanoparticles have proven to be extremely robust, showing excellent signal strength, negligible photobleaching, and minimal loss of functional organic components. The native or free surface of the volume-labeled particles can be altered to achieve a specific surface functionality without altering fluorescence. Their utility was demonstrated for visualizing the association of surface modified fluorescent particles with cultured macrophages. Differences in particle agglomeration and cell association were clearly associated with differences in observed nanoparticle toxicity. The capacity to maintain particle fluorescence while making significant changes to surface chemistry makes these particles extremely versatile and useful for studies of particle agglomeration, uptake, and transport in environmental and biological systems.

Wang, Wei [ORNL] [ORNL; Foster, Carmen M [ORNL] [ORNL; Morrell-Falvey, Jennifer L [ORNL] [ORNL; Nallathamby, Prakash D [ORNL] [ORNL; Mortensen, Ninell P [ORNL] [ORNL; Doktycz, Mitchel John [ORNL] [ORNL; Gu, Baohua [ORNL] [ORNL; Retterer, Scott T [ORNL] [ORNL; Gu, Baohua [ORNL] [ORNL

2013-01-01

340

Volume labeling with Alexa Fluor dyes and surface functionalization of highly sensitive fluorescent silica (SiO2) nanoparticles.  

PubMed

A new synthesis approach is described that allows the direct incorporation of fluorescent labels into the volume or body of SiO2 nanoparticles. In this process, fluorescent Alexa Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and a polydispersity of <15%. In comparison with conventional surface tagged particles created by post-synthesis modification, this process maintains the physical and surface chemical properties that have the most pronounced effect on colloidal stability and interactions with their surroundings. These volume-labeled nanoparticles have proven to be extremely robust, showing excellent signal strength, negligible photobleaching, and minimal loss of functional organic components. The native or "free" surface of the volume-labeled particles can be altered to achieve a specific surface functionality without altering fluorescence. Their utility was demonstrated for visualizing the association of surface-modified fluorescent particles with cultured macrophages. Differences in particle agglomeration and cell association were clearly associated with differences in observed nanoparticle toxicity. The capacity to maintain particle fluorescence while making significant changes to surface chemistry makes these particles extremely versatile and useful for studies of particle agglomeration, uptake, and transport in environmental and biological systems. PMID:24056530

Wang, Wei; Nallathamby, Prakash D; Foster, Carmen M; Morrell-Falvey, Jennifer L; Mortensen, Ninell P; Doktycz, Mitchel J; Gu, Baohua; Retterer, Scott T

2013-11-01

341

Far-red and near infrared BODIPY dyes: synthesis and applications for fluorescent pH probes and bio-imaging.  

PubMed

Far-red and near infrared (NIR) emissive dyes have advantages in the development of fluorescent probes and labelling for bio-imaging in living systems since fluorescence in the long-wavelength region would generate minimum photo-toxicity to biological components, deep tissue penetration and minimal background from auto-fluorescence by bio-molecules. BODIPY dyes are attractive due to their excellent photo-physical properties and potential for fluorescence-based sensing and bio-imaging applications. Thus, numerous research papers have emerged to develop BODIPY-based dyes with absorption and emission in the long-wavelength spectral region (650-900 nm). This review summarizes the general strategies to obtain far-red and NIR BODIPYs. Moreover, their applications for fluorescent pH probes and imaging or labelling in living systems are highlighted. PMID:24781214

Ni, Yong; Wu, Jishan

2014-05-21

342

Construction of NIR and ratiometric fluorescent probe for Hg2+ based on a rhodamine-inspired dye platform.  

PubMed

A rhodamine-inspired fluorescence dye (2) bearing 7-diethylaminocoumarin fluorophore was designed as a platform for the construction of an NIR and ratiometric fluorescent probe. The ring-open form of 2 shows NIR absorption and emission; however, its ring-closed form displays the visible absorption and emission because an intact 7-diethylaminocoumarin fluorophore was involved in the structure, providing the basis for an NIR and ratiometric fluorescent platform based on the spirocyclization-induced fluorescence switching mechanism. With the platform, we developed a novel NIR and ratiometric fluorescent probe R1, a thiolactone of 2, for sensing Hg2+, an environmentally and biologically concerned species. R1 displays an emission peak with the maximum at 480 nm, which is the typical emission of 7-diethylaminocoumarin moiety; however, upon addition of Hg2+ ions, the emission intensity at 480 nm gradually decreased with the simultaneous appearance of a new NIR emission band centred at 695 nm. Thus, the Hg2+-promoted ratiometric fluorescence response can be realized. The high selectivity towards Hg2+ over various cations and the high stability in a wide pH range of 1–12 indicate its potential for applications in biological systems. The subsequent cell imaging experiment revealed that R1 is cell permeable, and could be employed for ratiometric fluorescence imaging of Hg2+ in living cells. PMID:23486695

Liu, Jing; Sun, Yuan-Qiang; Wang, Pi; Zhang, Jingyu; Guo, Wei

2013-05-01

343

A comparison of the sensitivity of immunoperoxidase staining methods with high-sensitivity fluorescence flow cytometry-antibody quantitation on the cell surface.  

PubMed

Surface molecules present in low copy numbers can be detected with high-sensitivity fluorescence flow cytometry. Many cells previously thought not to express certain molecules on their surface can now be shown to have these molecules in very low copy numbers by high-sensitivity fluorescent cytometric methods. Detection of molecules by immunoperoxidase staining methods has not previously been compared with high-sensitivity flow cytometry techniques. Computerized video image analysis (VIA) is a method that allows measurement of area and density of the immunostain chromogen reaction product in a standardized fashion analogous to flow cytometry. In this study, we compared immunoperoxidase reaction products measured by VIA methods with high-sensitivity flow cytometric measurements for cells with 10,000 down to 50 antibody molecules bound to their surfaces. Detection of 100-200 surface molecules was possible with heavy metal-enhanced immunoperoxidase methods, whereas standard immunoperoxidase methods were not as sensitive. The sensitivity of the nickel-enhanced immunoperoxidase staining method was confirmed for detection of an epitope (Tac-IL2 receptor alpha-chain) present in low numbers on the surface of peripheral blood lymphocytes. PMID:8027533

Coventry, B J; Neoh, S H; Mantzioris, B X; Skinner, J M; Zola, H; Bradley, J

1994-08-01

344

Symplastic Transfer of Fluorescent Dyes from Mesophyll to Sieve Tube in Stripped Leaf Tissue and Partly Isolated Minor Veins of Commelina benghalensis.  

PubMed

We have stripped small (3 x 3 mm) fields of the upper and the opposite lower epidermis of Commelina benghalensis leaves. Pectinase treatment of the resulting chlorenchyma windows produced free-lying viable minor veins with small lumps of mesophyll cells attached. These veins were still connected with the intact remainder of the leaf. Fluorescent dyes were injected into mesophyll cells or mestome sheath cells. Continuous following of the dye from the moment of injection and use of the simple vein system allowed an unhindered and precise assessment of the cell-to-cell route of dye transfer. Disodium fluorescein and Lucifer Yellow CH injected into mesophyll or mestome sheath cells readily moved to the sieve tube. This symplastic dye transfer from mesophyll to sieve tube was also observed after injection into unmacerated stripped leaf tissue. The displacement of fluorescent dyes substantiates a symplastic continuity between mesophyll and sieve tube and therefore supports the possibility of symplastic phloem loading. PMID:16666366

van Kesteren, W J; van der Schoot, C; van Bel, A J

1988-11-01

345

Synthesis and photophysical properties of some novel fluorescent dyes based on naphthalimide derivatives  

Microsoft Academic Search

A series of novel naphthalimide dyes with amino and acetylamino functional groups were synthesized through imidation, reduction and acetylation reactions on 4-nitro-1,8-naphthalic anhydride. The synthesized dyes were characterized by DSC, TLC (Rf values), FTIR, 1HNMR, 13CNMR, UV–visible and Fluorometery. Molar extinction coefficients and wavelength maxima were obtained by examining dye solutions in DMF and THF. The results demonstrated that the

H. Shaki; K. Gharanjig; S. Rouhani; A. Khosravi

2010-01-01

346

Simultaneous optical coherence tomography-Indocyanine Green dye fluorescence imaging system for investigations of the eye's fundus  

NASA Astrophysics Data System (ADS)

We have developed a dual-channel optical coherence tomography-Indocyanine Green dye (OCT-ICG) fluorescence system based on a previously reported ophthalmic OCT confocal imaging system. The confocal channel is tuned to the fluorescence wavelength range of the ICG, and light from the same optical source is used to generate the OCT image and to excite the ICG fluorescence. The system enables the clinician to visualize simultaneously en face OCT slices and corresponding ICG angiograms of the ocular fundus, displayed side by side. C-scan (constant depth) and B-scan (cross section) images are collected by a fast en face scan (T scan). The pixel-to-pixel correspondence between the OCT and angiography images allows the user to capture OCT Bscans precisely at selected points on the ICG confocal images.

Dobre, George M.; Podoleanu, Adrian Gh.; Rosen, Richard B.

2005-01-01

347

In vivo fluorescence imaging of lysosomes: a potential technique to follow dye accumulation in the context of PDT?  

NASA Astrophysics Data System (ADS)

Lysosomes and intracellular acidic compartments seem to play an important role in the context of PDT. Some photosensitizers are localized in the lysosomes of tumor-associated macrophages. Liposomes, which are lysosomotropic drug carriers, are used to deliver photosensitizers in tumors. Liposomes are taken up by the liver cells after intravenous injection. Intracellular pathway and liposomes localization in the different liver cells require sacrifice of the animals, cell separation, and observation by electronic microscopy. Little is known about liposomes kinetic uptake by the acidic intracellular compartments in vivo. We propose in this study a new method to follow liposomes uptake in the liver in vivo using a fluorescent pH-sensitive probe. We have already demonstrated the ability of fluorescence spectroscopy and imaging using a pH-dependent probe to monitor pH in living tissues. As pH of lysosome is very low, the kinetic of liposome uptake in this intracellular acidic compartment is followed by monitoring the pH of the whole liver in vivo and ex vivo. Liposomes-encapsulated carboxyfluorescein are prepared by the sonication procedure. Carboxyfluorescein is used at high concentration (100 mM) in order to quench its fluorescence. Liposomes are injected to Wistar rats into the peinil vein. After laparotomy, fluorescence spectra and images are recorded during two hours. Results show a rapid fluorescence increase followed by a slow phase of fluorescence decrease. pH decreases from physiological value to 6.0. After sacrifice and flush with cold saline solution, pH of liver ex vivo is found to be 5.0 - 5.5. These data show a rapid clearance of released dye and an uptake of liposomes by the liver cells and, as liposomes penetrate in the acidic compartment, dye is released from liposomes and is delivered in lysosomes leading to the decrease of pH.

Devoisselle, Jean-Marie; Mordon, Serge R.; Soulie-Begu, Sylvie

1995-03-01

348

In vivo fluorescence imaging of lysosomes: a potential technique to follow dye accumulation in the context of PDT?  

NASA Astrophysics Data System (ADS)

Lysosomes and intracellular acidic compartments seem to play an important role in the context of PDT. Some photosensitizers are localized in the lysosomes of tumor-associated macrophages. Liposomes, which are lysosomotropic drug carriers, are used to deliver photosensitizers in tumors. Liposomes are taken up by the liver cells after intravenous injection. Intracellular pathway and liposomes localization in the different liver cells require sacrifice of the animals, cell separation, and observation by electronic microscopy. Little is known about liposomes kinetic uptake by the acidic intracellular compartments in vivo. We propose in this study a new method to follow liposomes uptake in the liver in vivo using a fluorescent pH-sensitive probe. We have already demonstrated the ability of fluorescence spectroscopy and imaging using a pH-dependent probe to monitor pH in living tissues. As pH of lysosome is very low, the kinetic of liposome uptake in this intracellular acidic compartment is followed by monitoring the pH of the whole liver in vivo and ex vivo. Liposomes-encapsulated carboxyfluorescein are prepared by the sonication procedure. Carboxyfluorescein is used at high concentration (100 mM) in order to quench its fluorescence. Liposomes are injected to Wistar rats into the peinil vein. After laparotomy, fluorescence spectra and images are recorded during two hours. Results show a rapid fluorescence increase followed by a slow phase of fluorescence decrease. pH decreases from physiological value to 6.0. After sacrifice and flush with cold saline solution, pH of liver ex vivo is found to be 5.0 - 5.5. These data show a rapid clearance of released dye and an uptake of liposomes by the liver cells and, as liposomes penetrate in the acidic compartment, dye is released from liposomes and is delivered in lysosomes leading to the decrease of pH.

Devoisselle, Jean-Marie; Mordon, Serge R.; Soulie-Begu, Sylvie

1994-10-01

349

Near-infrared fluorescence laparoscopy of the cystic duct and artery in pigs: performance of a preclinical dye.  

PubMed

Abstract Background: Near-infrared fluorescence laparoscopy after intravenous indocyanine green (ICG) administration has been proposed as a promising surgical imaging technique for real-time visualization of the extrahepatic bile ducts and arteries in clinical laparoscopic cholecystectomies. However, optimization of this new technique with respect to the imaging system combined with the fluorophore is desirable. The performance of a preclinical near-infrared dye, CW800-CA, was compared with that of ICG for near-infrared fluorescence laparoscopy of the cystic duct and artery in pigs. Materials and Methods: Laparoscopic cholecystectomy was performed in six pigs (average weight, 35?kg) using a commercially available laparoscopic fluorescence imaging system. The fluorophores CW800-CA and ICG (both 800?nm fluorescent dyes) were administered by intravenous injection in four and two pigs, respectively. CW800-CA was administered in three different doses (consecutively 0.25, 1, and 3?mg); ICG was intravenously injected (2.5?mg) for comparison. Intraoperative recognition of the biliary structures was recorded at set time points. The target-to-background ratio was determined to quantify the fluorescence signal of the designated tissues. Results: A clinically proven dose of 2.5?mg of ICG resulted in a successful fluorescence delineation of both the cystic duct and artery. In the CW800-CA-injected pigs a clear visualization of the cystic duct and artery was obtained after administration of 3?mg of CW800-CA. Time from injection until fluorescence identification of the cystic duct was reduced when CW800-CA was used compared with ICG (11.5 minutes versus 21.5 minutes, respectively). CW800-CA provided clearer illumination of the cystic artery, in terms of target-to-background ratio. Conclusions: As well as ICG, CW800-CA can be applied for fluorescence identification of the cystic artery and duct using a commercially available laparoscopic fluorescence imaging system. Fluorescence cholangiography of the cystic duct can be obtained earlier after intravenous injection of CW800-CA, compared with ICG. These findings increase the possibilities of use and of optimization of this imaging technique. PMID:24742306

Schols, Rutger M; Lodewick, Toine M; Bouvy, Nicole D; van Dam, Dieuwertje A; Meijerink, Wilhelmus J H J; van Dam, Gooitzen M; Dejong, Cornelis H C; Stassen, Laurents P S

2014-05-01

350

Synthesis, characterization, and application of cy-dye- and alexa-dye-labeled hongotoxin(1) analogues. The first high affinity fluorescence probes for voltage-gated K+ channels.  

PubMed

Hongotoxin(1) (HgTX(1)), a 39-residue peptide recently isolated from the venom of Centruroides limbatus, blocks the voltage-gated K+ channels K(v)1.1, K(v)1.2, and K(v)1.3 at picomolar toxin concentrations (Koschak, A., Bugianesi, R. M., Mitterdorfer, J., Kaczorowski, G. J., Garcia, M. L., and Knaus, H. G. (1998) J. Biol. Chem. 273, 2639-2644). In this report, we determine the three-dimensional structure of HgTX(1) using NMR spectroscopy (PDB-code: 1HLY). HgTX(1) was found to possess a structure similar to previously characterized K+ channel toxins (e.g. margatoxin) consisting of a three-stranded antiparallel beta-sheet (residues 2-4, 26-30, and 33-37) and a helical conformation (part 3(10) helix and part alpha helix; residues 10-20). Due to the importance of residue Lys-28 for high-affinity interaction with the respective channels, lysine-reactive fluorescence dyes cannot be used to label wild-type HgTX(1). On the basis of previous studies (see above) and our NMR data, a HgTX(1) mutant (HgTX(1)-A19C) was engineered, expressed, and purified. HgTX(1)-A19C-SH was labeled using sulfhydryl-reactive Cy3-, Cy5-, and Alexa-dyes. Pharmacological characterization of fluorescently labeled HgTX(1)-A19C in radioligand binding studies indicated that these hongotoxin(1) analogues retain high-affinity for voltage-gated K+ channels and a respective pharmacological profile. Cy3- and Alexa-dye-labeled hongotoxin(1) analogues were used to investigate the localization of K+ channels in brain sections. The distribution of toxin binding closely follows the distribution of K(v)1.2 immunoreactivity with the highest expression levels in the cerebellar Purkinje cell layer. Taken together, these results demonstrate that fluorescently labeled HgTX(1) analogues comprise novel probes to characterize a subset of voltage-gated K+ channels. PMID:12009929

Pragl, Bernt; Koschak, Alexandra; Trieb, Maria; Obermair, Gerald; Kaufmann, Walter A; Gerster, Uli; Blanc, Eric; Hahn, Christoph; Prinz, Heino; Schütz, Gerhard; Darbon, Herve; Gruber, Hermann J; Knaus, Hans-Günther

2002-01-01

351

Role of Rare Earth Oxide Nanoparticles (CeO2 and La 2O 3) in Suppressing the Photobleaching of Fluorescent Organic Dyes.  

PubMed

Aqueous solutions with Rhodamine dye, and fluorescently labeled polymer samples of fibrin and collagen were mixed with aqueous dispersions of cerium oxide, lanthanum oxide, iron (II) oxide nanoparticles, and OxyFluor, a commonly used reagent for suppressing photobleaching. From time dependent studies of the fluorescence from these samples, we observed that the dyes in samples containing rare earth oxide nanoparticles exhibited significantly slower rates of fluorescence decay compared to control samples without additives, or containing OxyFluor or iron oxide nanoparticles. We posit that this may be related to the oxygen free radical scavenging properties of rare earth oxides. PMID:24706286

Guha, Anubhav; Basu, Anindita

2014-05-01

352

A simple method for staining of nucleoproteide equivalents in human FL cell chromosomes.  

PubMed

Chick embryo cell monolayers (CEC) treated by acidified thiazine dyes (pH 5 to 3) arrived into a mitogenic state. The diffuse dispersed chromatin of the nuclei clustered on the nuclear membranes and on the nucleoli in chromosome-like figures is usually estimated by electron microscopy. The clustering process could better be followed by light microscopy. The same treatment with acidified thiazine dyes on Fogh and Lund (FL) cell monolayers led unequivocally to induction of pre-formed chromosomes in interphasic cells with the same location as in the CEC. On the other hand, in metaphasic nuclei of FL cells, the above stain showed a cluster of deeply stained granules and pale stained strings. The last cluster model could be observed in the interior of metaphasic chromosomes aligned along the chromosomal arms in longitudinal, horizontal and/or crisscross position. These cluster patterns differ from conventional chromosomal bands obtained by Giemsa of fluorescent staining. PMID:2424278

Tonew, M S

1985-01-01

353

Interactions of L-Arg with calf thymus DNA using neutral red dye as a fluorescence probe.  

PubMed

The interaction between l-Arg and calf thymus DNA (ctDNA) in sodium acetate-acetic acid buffer (pH=4) was investigated with the use of neutral red (NR) dye as a spectral probe coupled with UV-vis absorption, fluorescence, and circular dichroism (CD) spectroscopy technique. The UV absorption spectroscopy indicated that l-Arg interacted with ctDNA via electrostatic force and the fluorescence enhancing of the DNA-NR system verified the electrostatic interaction. In addition, detectable changes in the CD spectrum of ctDNA in the presence of l-Arg indicated conformational changes in the DNA double helix after interaction with the drug. Docking studies were found to corroborate the experimental results. All these results prove that this drug interacts with ctDNA via an electrostatic binding mode. PMID:22842133

Lin, Jing; Liu, Rutao; Gao, Canzhu

2012-11-01

354

[Determination of four Sudan dyes in chili oil by high performance liquid chromatography with on-line photochemical derivatization and fluorescence detection].  

PubMed

A method for the measurement of Sudan I, Sudan II, Sudan III and Sudan B in chili oil using high performance liquid chromatography (HPLC) with on-line photochemical derivatization and fluorescence detection has been developed. The Sudan dyes were separated on an SB-C18 column in a single run by the mixed mobile phase of acetonitrile-water with a gradient program. A laboratory-built time/energy programmed photochemical reactor (PCR) with an ultraviolet mercury lamp was installed between a photodiode array detector (PDA) and a fluorescence detector (FLD), and it was applied to convert the non-or weakly fluorescent Sudan dyes into fluorescence emission components. The photochemical derivatization conditions and fluorescence detection parameters have been investigated and optimized. The recoveries of the standards spiked in real chili oil samples for all the dyes were 81.3% - 100.4%. The relative standard deviations (RSDs, n = 6) of the fluorescence signal intensity at the spiked level of 0.8 mg/kg were 2.6% - 3.8%. The limits of detection (LODs) were in the range of 0.009 - 0.054 mg/kg and the limits of quantification (LOQs) were 0.030 - 0.181 mg/kg, which were better than those of the commonly used HPLC coupled with PDA. The developed method which is simple, sensitive, and selective can be applied to the routine analysis of Sudan dyes. PMID:23016298

Liu, Jun; Gong, Zhenbin

2012-06-01

355

Incorporating Fluorescent Dyes and Quantum Dots into Magnetic Microbeads for Immunoassays.  

National Technical Information Service (NTIS)

Microbeads that are both paramagnetic and fluorescently labeled are commercially available in colors spanning the visible spectrum. Although these commercial beads can be bright, polydispersity in both size and fluorescent intensity limit their use in qua...

H. Mattoussi L. J. Whitman S. P. Mulvaney

2004-01-01

356

A highly sensitive fluorescent indicator dye for calcium imaging of neural activity in vitro and in vivo.  

PubMed

Calcium imaging of individual neurons is widely used for monitoring their activity in vitro and in vivo. Synthetic fluorescent calcium indicator dyes are commonly used, but the resulting calcium signals sometimes suffer from a low signal-to-noise ratio (SNR). Therefore, it is difficult to detect signals caused by single action potentials (APs) particularly from neurons in vivo. Here we showed that a recently developed calcium indicator dye, Cal-520, is sufficiently sensitive to reliably detect single APs both in vitro and in vivo. In neocortical neurons, calcium signals were linearly correlated with the number of APs, and the SNR was > 6 for in vitro slice preparations and > 1.6 for in vivo anesthetised mice. In cerebellar Purkinje cells, dendritic calcium transients evoked by climbing fiber inputs were clearly observed in anesthetised mice with a high SNR and fast decay time. These characteristics of Cal-520 are a great advantage over those of Oregon Green BAPTA-1, the most commonly used calcium indicator dye, for monitoring the activity of individual neurons both in vitro and in vivo. PMID:24405482

Tada, Mayumi; Takeuchi, Atsuya; Hashizume, Miki; Kitamura, Kazuo; Kano, Masanobu

2014-06-01

357

Evaluation of quantum dot-based concentric FRET configurations with a fluorescent dye and dark quencher for multiplexed bioanalyses  

NASA Astrophysics Data System (ADS)

Semiconductor quantum dots (QDs) continue to emerge as a highly advantageous platform for bioanalysis. Their unique physical and optical properties are especially well suited for Förster resonance energy transfer (FRET)-based bioprobes. Concentric FRET configurations are a recent development in this area of research and are best described as QD bioconjugates where multiple energy transfer pathways have been assembled around the central QD. Concentric FRET configurations permit multiplexed bioanalysis using one type of QD vector, but require more sophisticated analyses than conventional FRET pairs. In this paper, we describe the design and characterization of a new concentric FRET configuration that assembles both a fluorescent dye, Alexa Fluor 555 or Alexa Fluor 647, and a dark quencher, QSY9, at different ratios around a central CdSeS/ZnS QD. It was found that the magnitudes of the total photoluminescence (PL) intensity and either the A555/QD or A647/QD PL ratio can be related to the number of QSY9 and A555 or A647 per QD. The trends in these parameters with changes in the number of each dye molecule per QD have both similarities and differences between configurations with A555 and A647. In each case, a system of equations can be defined to permit calculation of the number of each dye molecule per QD from PL measurements. Both of these dark quencher-based concentric FRET configurations are therefore good candidates for quantitative, multiplexed bioanalysis.

Conroy, Erin M.; Algar, W. Russ

2014-03-01

358

Consideration of fluorescence properties for the direct determination of erythrosine in saffron in the presence of other synthetic dyes.  

PubMed

Direct selective detection of erythrosine in saffron in the presence of other synthetic dyes considers its fluorescence at 532 nm excitation/548 nm emission. Saffron pre-treatment was according to the ISO 3632-2 trade standard test methods. On account of calculated quantum yield values, none of the yellow dyes is expected to interfere. Among red ones, reservations about allura red AC, azorubine and red 2G were not verified by experimentation, signifying excellent method specificity. Detection and quantification limits (0.56 and 1.70 nM) were of the same magnitude as those reported in the literature after chromatographic separation of erythrosine. The percentage recovery from spiked saffron samples ranging from 63 to 141 was acceptable for residue levels in foods. The matrix effect from crocins (saffron pigments) was evidenced only at a lower spiking level (0.02 mg kg(-1)). The minimum required performance limit (MRPL) was 0.04 mg kg(-1), indicating that the method is appropriate for determining traces of erythrosine in saffron. The approach offers improved sensitivity (by three orders of magnitude) and specificity than the direct spectrophotometric detection of certain synthetic dyes in saffron and deserves attention by the ISO Technical Committee for 'Herbs, culinary spices and condiments'. PMID:21337237

Ordoudi, S A; Tsimidou, M Z

2011-04-01

359

Fluorescence characterization of the ternary system TMQ-PBDBD365-POPOP-dye-doped polystyrene optical fiber under gamma and UV irradiation  

NASA Astrophysics Data System (ADS)

Polystyrene dye doped plastic optical fiber was prepared and used to detect gamma and beta radiation from I151 and TeO(subscript 4 gamma tracers typically used to get images of tumor areas within the human body. Absorption and fluorescence emission of TMQ, PBDBD365, POPOP styrene doped was performed under gamma and UV-irradiation. The fluorescence efficiency of the binary system PBDBD365-POPOP and the ternary TMQ- PBDBD365-POPOP was compared and according to the experimental results it was shown that the presence of the TMQ dye enhance the fluoresce obtained under I151 radiation. Systematic characterization of the binary system was performed as function of primary dye concentration .

de la Rosa-Cruz, Elder; Diaz-Torres, Luis A.; Rodriguez-Rojas, R. A.; Kumar, G. A.; Dirk, Carl W.; Rodriguez, Osvaldo; Kopecky, Sarah; Hernandez, Jose M.; Diaz-Torres, Y.

2001-12-01

360

DNA complexes with dyes designed for energy transfer as fluorescent markers  

DOEpatents

Heteromultimeric fluorophores are provided for binding to DNA, which allow for the detection of DNA in electrical separations and preparation of probes having high-fluorescent efficiencies and large Stokes shifts. In addition, by appropriate choice of fluorescent molecules, one can use a single narrow wavelength band excitation light source, while obtaining fluorescent emissions having sufficient separation to be readily discriminated. 4 figures.

Glazer, A.N.; Benson, S.C.

1995-03-28

361

DNA complexes with dyes designed for energy transfer as fluorescent markers  

DOEpatents

Heteromultimeric fluorophores are provided for binding to DNA, which allow for the detection of DNA in electrical separations and preparation of probes having high-fluorescent efficiencies and large Stokes shifts. In addition, by appropriate choice of fluorescent molecules, one can use a single narrow wavelength band excitation light source, while obtaining fluorescent emissions having sufficient separation to be readily discriminated.

Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Albany, CA)

1997-01-01

362

DNA complexes with dyes designed for energy transfer as fluorescent markers  

DOEpatents

Heteromultimeric fluorophores are provided for binding to DNA, which allow for the detection of DNA in electrical separations and preparation of probes having high-fluorescent efficiencies and large Stokes shifts. In addition, by appropriate choice of fluorescent molecules, one can use a single narrow wavelength band excitation light source, while obtaining fluorescent emissions having sufficient separation to be readily discriminated.

Glazer, Alexander M. (Orinde, CA); Benson, Scott C. (Albany, CA)

1998-01-01

363

DNA complexes with dyes designed for energy transfer as fluorescent markers  

DOEpatents

Heteromultimeric fluorophores are provided for binding to DNA, which allow for the detection of DNA in electrical separations and preparation of probes having high-fluorescent efficiencies and large Stokes shifts. In addition, by appropriate choice of fluorescent molecules, one can use a single narrow wavelength band excitation light source, while obtaining fluorescent emissions having sufficient separation to be readily discriminated.

Glazer, Alexander M. (Orinda, CA); Benson, Scott C. (Albany, CA)

1999-01-01

364

DNA complexes with dyes designed for energy transfer as fluorescent markers  

DOEpatents

Heteromultimeric fluorophores are provided for binding to DNA, which allow for the detection of DNA in electrical separations and preparation of probes having high-fluorescent efficiencies and large Stokes shifts. In addition, by appropriate choice of fluorescent molecules, one can use a single narrow wavelength band excitation light source, while obtaining fluorescent emissions having sufficient separation to be readily discriminated.

Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Albany, CA)

1995-01-01

365

DNA complexes with dyes designed for energy transfer as fluorescent markers  

SciTech Connect

Heteromultimeric fluorophores are provided for binding to DNA, which allow for the detection of DNA in electrical separations and preparation of probes having high-fluorescent efficiencies and large Stokes shifts. In addition, by appropriate choice of fluorescent molecules, one can use a single narrow wavelength band excitation light source, while obtaining fluorescent emissions having sufficient separation to be readily discriminated.

Glazer, A.M.; Benson, S.C.

1999-11-02

366

Indocyanine dyes approach free rotation at the 3' terminus of A-RNA: a comparison with the 5' terminus and consequences for fluorescence resonance energy transfer.  

PubMed

Cyanine dyes are widely used to study the folding and structural transformations of nucleic acids using fluorescence resonance energy transfer (FRET). The extent to which FRET can be used to extract inter- and intramolecular distances has been the subject of considerable debate in the literature; the contribution of dye and linker dynamics to the observed FRET signal is particularly troublesome. We used molecular dynamics (MD) simulations to study the dynamics of the indocarbocyanine dyes Cy3 and Cy5 attached variously to the 3' or 5' terminal bases of a 16-base-pair RNA duplex. We then used Monte Carlo modeling of dye photophysics to predict the results of single-molecule-sensitive FRET measurements of these same molecules. Our results show that the average value of FRET depends on both the terminal base and the linker position. In particular, 3' attached dyes typically explore a wide region of configuration space, and the relative orientation factor, ?(2), has a distribution that approaches that of free-rotators. This is in contrast to 5' attached dyes, which spend a significant fraction of their time in one or more configurations that are effectively stacked on the ends of the RNA duplex. The presence of distinct dye configurations for 5' attached dyes is consistent with observations, made by others, of multiple fluorescence lifetimes of Cy3 on nucleic acids. Although FRET is frequently used as a molecular "ruler" to measure intramolecular distances, the unambiguous measurement of distances typically relies on the assumption that the rotational degrees of freedom of the dyes can be averaged out and that the donor lifetime in the absence of the acceptor is a constant. We demonstrate that even for the relatively free 3' attached dyes, the correlation time of ?(2) is still too long to justify the use of a free-rotation approximation. We further explore the consequences of multiple donor lifetimes on the predicted value of FRET. PMID:23799279

Milas, Peker; Gamari, Ben D; Parrot, Louis; Krueger, Brent P; Rahmanseresht, Sheema; Moore, James; Goldner, Lori S

2013-07-25

367

Gram Stain  

MedlinePLUS

... an infected site are the most commonly performed microbiology tests used to identify the cause of a ... 2012) Cavanaugh D, Keen M, American Society for Microbiology. The Gram Stain: An Animated Approach. Available online ...

368

Negative Staining  

NSDL National Science Digital Library

This video from CUNY Kingsborough Community College describes negative staining. The brief demonstration is described step by step and would be easy to replicate in a laboratory setting. Running time for the video is 1:32.

2013-06-21

369

Properties of two-photon fluorescence and superradiance of a new organic dye C46H51N2B  

NASA Astrophysics Data System (ADS)

Linear and nonlinear optical properties of a new organic dye, trans-4-[ p-(N-n-butyl-N-n-butylamino)-styryl] -N-methyl-pyridinium tetraphenylborate solution in dimethyl formamide (DMF) have been studied systematically. When excited with mode-locked picosecond 1 064 nm laser beam, intense upconversion fluorescence and superradiance can be obtained. The temporal behaviors of one-photon absorption and two-photon absorption (TPA) fluorescence and superradiance have been studied. The highest upconversion efficiency was found to be 4.1% at a pump energy of 4 mJ. By using an optical parameter amplifier (OPA) as the pump laser, the nonlinear transmittance and upconversion efficiencies of the dye solution at different wavelengths were measured. The strongest linear absorption was found at a wavelength of 930 nm whereas the highest upconversion efficiency was at 1 030 nm. The 100 nm red-shift for the highest upconversion efficiency wavelength compared with the strongest nonlinear absorption are caused by excited state absorption.

Zhou, G.; Wang, D.; Yang, S.; Ren, Y.; Xu, X.; Shao, Z.; Zhao, X.; Jiang, M.; Tian, Y.; Hao, F.; Li, S.; Shi, P.

2002-06-01

370

Highly Photostable Near-Infrared Fluorescent pH Indicators and Sensors Based on BF2-Chelated Tetraarylazadipyrromethene Dyes  

PubMed Central

In this study, a series of new BF2-chelated tetraarylazadipyrromethane dyes are synthesized and are shown to be suitable for the preparation of on/off photoinduced electron transfer modulated fluorescent sensors. The new indicators are noncovalently entrapped in polyurethane hydrogel D4 and feature absorption maxima in the range 660–710 nm and fluorescence emission maxima at 680–740 nm. Indicators have high molar absorption coefficients of ?80?000 M–1 cm–1, good quantum yields (up to 20%), excellent photostability and low cross-sensitivity to the ionic strength. pKa values of indicators are determined from absorbance and fluorescence measurements and range from 7 to 11, depending on the substitution pattern of electron-donating and -withdrawing functionalities. Therefore, the new indicators are suitable for exploitation and adaptation in a diverse range of analytical applications. Apparent pKa values in sensor films derived from fluorescence data show 0.5–1 pH units lower values in comparison with those derived from the absorption data due to Förster resonance energy transfer from protonated to deprotonated form. A dual-lifetime referenced sensor is prepared, and application for monitoring of pH in corals is demonstrated.

2012-01-01

371

Highly photostable near-infrared fluorescent pH indicators and sensors based on BF2-chelated tetraarylazadipyrromethene dyes.  

PubMed

In this study, a series of new BF(2)-chelated tetraarylazadipyrromethane dyes are synthesized and are shown to be suitable for the preparation of on/off photoinduced electron transfer modulated fluorescent sensors. The new indicators are noncovalently entrapped in polyurethane hydrogel D4 and feature absorption maxima in the range 660-710 nm and fluorescence emission maxima at 680-740 nm. Indicators have high molar absorption coefficients of ~80,000 M(-1) cm(-1), good quantum yields (up to 20%), excellent photostability and low cross-sensitivity to the ionic strength. pK(a) values of indicators are determined from absorbance and fluorescence measurements and range from 7 to 11, depending on the substitution pattern of electron-donating and -withdrawing functionalities. Therefore, the new indicators are suitable for exploitation and adaptation in a diverse range of analytical applications. Apparent pK(a) values in sensor films derived from fluorescence data show 0.5-1 pH units lower values in comparison with those derived from the absorption data due to Förster resonance energy transfer from protonated to deprotonated form. A dual-lifetime referenced sensor is prepared, and application for monitoring of pH in corals is demonstrated. PMID:22738322

Jokic, Tijana; Borisov, Sergey M; Saf, Robert; Nielsen, Daniel A; Kühl, Michael; Klimant, Ingo

2012-08-01

372

Calmodulin activation of the Ca2+ pump revealed by fluorescent chelator dyes in human red blood cell ghosts  

PubMed Central

Ca2+ transport in red blood cell ghosts was monitored with fura2 or quin2 incorporated as the free acid during resealing. This is the first report of active transport monitored by the fluorescent intensity of the chelator dyes fura2 (5-50 microM) or quin2 (250 microM) in hemoglobin-depleted ghosts. Since there are no intracellular compartments in ghosts and the intracellular concentrations of all assay chelator substances including calmodulin (CaM), the dyes, and ATP could be set, the intracellular concentrations of free and total Ca [( Cafree]i and [Catotal]i) could be calculated during the transport. Ghosts prepared with or without CaM rapidly extruded Ca2+ to a steady- state concentration of 60-100 nM. A 10(4)-fold gradient for Ca2+ was routinely produced in medium containing 1 mM Ca2+. During active Ca2+ extrusion, d[Cafree]i/dt was a second order function of [Cafree]i and was independent of the dye concentration, whereas d[Catotal]i/dt increased as a first order function of both the [Cafree]i and the concentration of the Ca:dye complex. CaM (5 microM) increased d[Catotal]i/dt by 400% at 1 microM [Cafree]i, while d[Cafree]i/dt increased by only 25%. From a series of experiments we conclude that chelated forms of Ca2+ serve as substrates for the pump under permissive control of the [Cafree]i, and this dual effect may explain cooperativity. Free Ca2+ is extruded, and probably also Ca2+ bound to CaM or other chelators, while CaM and the chelators are retained in the cell.

1992-01-01

373

Evaluation of fluorescent dyes for the detection of mitochondrial membrane potential changes in cultured cardiomyocytes  

Microsoft Academic Search

Objective: Maintenance of the mitochondrial membrane potential (Dcm) is fundamental for the normal performance and survival of cells such as cardiomyocytes, that have a high energy requirement. Measurement of Dcm is therefore essential in order to develop an understanding of the molecular mechanisms controlling cardiomyocyte function. Here we have evaluated various potentiometric dyes for their ability to detect alterations of

Anthony Mathur; Ying Hong; Barbara K. Kemp; Alberto Alvarez Barrientos; Jorge D. Erusalimsky

374

Optical Properties of Fluorescent Mixtures: Comparing Quantum Dots to Organic Dyes  

ERIC Educational Resources Information Center

The study describes and compares the size-dependent optical properties of organic dyes with those of semiconductor nanocrystals or quantum dots (QDs). The analysis shows that mixtures of QDs contain emission colors that are sum of the individual QD components.

Hutchins, Benjamin M.; Morgan, Thomas T.; Ucak-Astarlioglu, Mine G.; Wlilliams, Mary Elizabeth

2007-01-01

375

Raman Spectra of Sudan Red Dyes and the Fluorescence Background Removal  

Microsoft Academic Search

Sudan red dyes, as illegal food additives, can induce carcinoma of bladder. It is important to find out a method to provide an easy, precise and sensitive detection. The aim of our study is to obtain the Raman feature frequency excursion of SudanI, IIand III, and draw clear Raman spectra. We used the Raman Systems R-3000 spectrometer to detect the

Chen Chen; Peng Fei; Cheng Qinghua; Xu Dahai

2010-01-01

376

Thermal damage assessment of blood vessels in a hamster skin flap model by fluorescence measurement of a liposome-dye system  

NASA Astrophysics Data System (ADS)

The present study was undertaken to evaluate the feasibility of thermal damage assessment of blood vessels by using laser-induced release of liposome-encapsulated dye. Experiments were performed in a hamster skin flap model. Laser irradiation was achieved with a 300micrometers fiber connected to a 805nm diode laser after potentiation using a specific indocyanine green (ICG) formulation. Liposomes- encapsulated carboxyfluorescein were prepared by the sonication procedure. Carboxyfluorescein was loaded at high concentration in order to quench its fluorescence. The measurements were performed after i.v. injection of DSPC liposomes and lasted 40 minutes. Fluorescence emission was measured with an ultra high sensitivity intensified camera. Three different shapes of fluorescent spots were identified depending on target and energy deposition in tissue: (i) intravascular fluorescence, (ii) transient low fluorescence circular spot and (iii) persistent high intense fluorescence spot. These images are correlated with histological data. The advantages of this liposome-dye system are (1) direct measurements can be obtained, (2) several repeated readings can be made from one injection, (3) continuous monitoring of the fluorescence can be made, (4) temperature-sensitive range can be adapted using different liposomes compositions, (5) circulation times of several hours can be achieved using DSPC liposomes (6) the tissue microcirculation and the vessel macrocirculation can be investigated simultaneously, therefore changes in response to a treatment regimen and/or ICG formulations can be detected. One main constraint exists: the fluorescent dye encapsulated into the liposomes has to be carefully chosen in order to avoid any direct absorption by the dye itself. In conclusion, one of the most significant applications of this experimental technique is the evaluation of various degrees of tissue thermal damage. It could be possible to consider the application of this technique in ophthalmology and dermatology and possibly for the evaluation of burn injury.

Mordon, Serge R.; Desmettre, Thomas; Devoisselle, Jean-Marie; Soulie-Begu, Sylvie

1997-06-01

377

Visualization of Phospholipid Domains in Escherichia coli by Using the Cardiolipin-Specific Fluorescent Dye 10-N-Nonyl Acridine Orange  

Microsoft Academic Search

Cardiolipin (CL)-specific fluorescent dye 10-N-nonyl-acridine orange (NAO) was used to visualize CL distribution in Escherichia coli cells of different phospholipid compositions. In a filamentous mutant containing only anionic phospholipids, green fluorescent spots were observed along the filaments at approximately regular intervals. Three-dimensional image reconstruction obtained by optical sectioning and a deconvolution algo- rithm revealed NAO-binding domains in the plane of

EUGENIA MILEYKOVSKAYA; WILLIAM DOWHAN

2000-01-01

378

A sensitive, viable-colony staining method using Nile red for direct screening of bacteria that accumulate polyhydroxyalkanoic acids and other lipid storage compounds  

Microsoft Academic Search

The oxazine dye Nile blue A and its fluorescent oxazone form, Nile red, were used to develop a simple and highly sensitive\\u000a staining method to detect poly(3-hydroxybutyric acid) and other polyhydroxyalkanoic acids (PHAs) directly in growing bacterial\\u000a colonies. In contrast to previously described methods, these dyes were directly included in the medium at concentrations of\\u000a only 0.5 ?g\\/ml, and growth

Patricia Spiekermann; Bernd H. A. Rehm; Rainer Kalscheuer; Dirk Baumeister; Alexander Steinbüchel

1999-01-01

379

In situ preparation of highly fluorescent pyrene-dyes from non-luminous precursors upon photoirradiation.  

PubMed

The non-luminous precursor, 2-(1-pyrenyl)-9,10-dihydro-9,10-ethanoanthracene-11,12-dione, was photochemically converted to highly-fluorescent 2-(1-pyrenyl)anthracene quantitatively in solution and in the PMMA film and the fluorescence quantum yield of the acene in benzonitrile was as high as 0.99. PMID:23536158

Aotake, Tatsuya; Tanimoto, Hiroshi; Hotta, Hidekatsu; Kuzuhara, Daiki; Okujima, Tetsuo; Uno, Hidemitsu; Yamada, Hiroko

2013-05-01

380

PCR and direct fluorescent-antibody staining confirm Chlamydia trachomatis antigens in swabs and urine below the detection threshold of Chlamydiazyme enzyme immunoassay.  

PubMed Central

In order to test the hypothesis that specimens blocking with a neutralizing reagent below the cutoff of the Chlamydiazyme enzyme immunoassay represent infected patients, we used direct fluorescent-antibody staining for elementary bodies (EBs) and PCR to confirm results for cervical swabs collected from 55,963 women and urethral swabs or first-void urine (FVU) samples collected from 5,781 men attending physicians' offices in the Toronto, Canada, area. Within a grey zone arbitrarily selected to represent values up to 40% below the positive threshold of the test run, 134 cervical swabs, 44 urethral swabs, and 39 FVU specimens exhibited a blocking response ( > 50% reduction in signal). Three or more EBs were observed in each of 98 cervical swabs (73.1%), 38 urethral swabs (86.4%), and 21 FVU specimens (53.8%). Of the 36 cervical swabs with fewer than three EBs, 33 were PCR positive; the positive PCR results for male specimens were 6 of 6 urethral swabs and 17 of 18 FVU samples. Application of the blocking test to specimens negative in the Chlamydiazyme enzyme immunoassay but having optical densities within 40% of the cutoff added 14.2% (217 of 1,531 specimens) more positive results to the survey. A total of 213 of 217 samples (98.2%) were reconfirmed as having EBs or DNA.

Krepel, J; Laur, I; Sproston, A; Luinstra, K; Jang, D; Mahony, J; Chernesky, M

1995-01-01

381

PCR and direct fluorescent-antibody staining confirm Chlamydia trachomatis antigens in swabs and urine below the detection threshold of Chlamydiazyme enzyme immunoassay.  

PubMed

In order to test the hypothesis that specimens blocking with a neutralizing reagent below the cutoff of the Chlamydiazyme enzyme immunoassay represent infected patients, we used direct fluorescent-antibody staining for elementary bodies (EBs) and PCR to confirm results for cervical swabs collected from 55,963 women and urethral swabs or first-void urine (FVU) samples collected from 5,781 men attending physicians' offices in the Toronto, Canada, area. Within a grey zone arbitrarily selected to represent values up to 40% below the positive threshold of the test run, 134 cervical swabs, 44 urethral swabs, and 39 FVU specimens exhibited a blocking response ( > 50% reduction in signal). Three or more EBs were observed in each of 98 cervical swabs (73.1%), 38 urethral swabs (86.4%), and 21 FVU specimens (53.8%). Of the 36 cervical swabs with fewer than three EBs, 33 were PCR positive; the positive PCR results for male specimens were 6 of 6 urethral swabs and 17 of 18 FVU samples. Application of the blocking test to specimens negative in the Chlamydiazyme enzyme immunoassay but having optical densities within 40% of the cutoff added 14.2% (217 of 1,531 specimens) more positive results to the survey. A total of 213 of 217 samples (98.2%) were reconfirmed as having EBs or DNA. PMID:8576331

Krepel, J; Laur, I; Sproston, A; Luinstra, K; Jang, D; Mahony, J; Chernesky, M

1995-11-01

382

Image analysis of HER2 immunohistochemical staining. Reproducibility and concordance with fluorescence in situ hybridization of a laboratory-validated scoring technique.  

PubMed

Image analysis of the HER2 immunohistochemical (IHC) stain can help determine which breast cancer patients may benefit from HER2-targeted therapy. We studied the concordance of HER2 IHC and fluorescence in situ hybridization (FISH) as well as reproducibility of surgical pathologist (SP) and cytotechnologist (CT) interpretations using manual and image analysis methodologies on 154 IHC cases. Concordances with FISH were good for IHC negative (0, 1+) cases (range, 97%-100%) and positive (3+) cases (range, 87%-100%). Image analysis had fewer equivocal (2+) results (10.4%) than CT (14.9%) and SP (16.2%) manual methods, with higher concordances to FISH (31%, 26%, and 20% for image analysis, CT manual, and SP manual, respectively). CT manual (? = 0.747) and image analysis (? = 0.779) methods had better interobserver reproducibility than SP manual (? = 0.697). CT image analysis had better intraobserver reproducibility (? = 0.882) than CT (? = 0.828) and SP (? = 0.766) manual methods. HER2 IHC analysis performed by image analysis can produce accurate results with improved reproducibility. PMID:22261453

Minot, Douglas M; Voss, Jesse; Rademacher, Susan; Lwin, Toe; Orsulak, Jessica; Caron, Bolette; Ketterling, Rhett; Nassar, Aziza; Chen, Beiyun; Clayton, Amy

2012-02-01

383

A multifunctional magnetic nanocarrier bearing fluorescent dye for targeted drug delivery by enhanced two-photon triggered release  

NASA Astrophysics Data System (ADS)

We report a novel nanoformulation for targeted drug delivery which utilizes nanophotonics through the fusion of nanotechnology with biomedical application. The approach involves an energy-transferring magnetic nanoscopic co-assembly fabricated of rhodamine B (RDB) fluorescent dye grafted gum arabic modified Fe3O4 magnetic nanoparticle and photosensitive linker by which dexamethasone drug is conjugated to the magnetic nano-assembly. The advantage offered by this nanoformulation is the indirect photo-triggered-on-demand drug release by efficient up-converting energy of the near-IR (NIR) light to higher energy and intraparticle energy transfer from the dye grafted magnetic nanoparticle to the linker for drug release by cleavage. The synthesized nanoparticles were found to be of ultra-small size (13.33 nm) and are monodispersed in an aqueous suspension. Dexamethasone (Dexa) drug conjugated to RDB-GAMNP by photosensitive linker showed appreciable release of Dexa by photo-triggered response on exposure to radiation having a wavelength in the NIR region whereas no detectable release was observed in the dark. Photo-triggered response for the nanoformulation not bearing the rhodamine B dye was drastically less as less Dexa was released on exposure to NIR radiation which suggest that the photo-cleavage of linker and release of Dexa mainly originated from the indirect excitation through the uphill energy conversions based on donor-acceptor model FRET. The promising pathway of nanophotonics for the on-demand release of the drug makes this nanocarrier very promising for applications in nanomedicine.

Banerjee, Shashwat S.; Chen, Dong-Hwang

2009-05-01

384

Criteria for selecting fluorescent dye tracers for soil hydrological applications using Uranine as an example  

EPA Science Inventory

Calibrating and verifying 2-D and 3-D vadose zone flow and transport models requires detailed information on water and solute redistribution. Among the different water flow and mass transfer determination methods, staining tracers have the best spatial resolution allowing visuali...

385

Photon Antibunching in the Fluorescence of a Single Dye Molecule Trapped in a Solid.  

National Technical Information Service (NTIS)

The correlation between fluorescence photons emitted by an optically pumped single molecule of pentacene in a p-terphenyl host has been investigated at short times. The correlation function shows photon antibunching, an unique feature of nonclassical radi...

T. Basche W. E. Moerner

1992-01-01

386

Fluorescence of the natural dye saffron: Selective reaction with eosinophil leucocyte granules  

Microsoft Academic Search

Treatment of methanol-fixed chicken, rat, horse and human blood smears with saturated solutions of saffron in borate buffer at pH 10 results in a bright yellow-green fluorescence reaction of the acidophilic cytoplasm granules in mammalian eosinophils and chicken heterophils under violet-blue exciting light. Spectral characteristics of saffron (emission peak at 543 nm under 436 nm excitation) and its selective fluorescence

Clara Isabel Trigoso; Juan Carlos Stockert

1995-01-01

387

Small volume excitation and enhancement of dye fluorescence on a 2D photonic crystal surface.  

PubMed

We demonstrate an easy-to-implement scheme for fluorescence enhancement and observation volume reduction using photonic crystals (PhCs) as substrates for microscopy. By normal incidence coupling to slow 2D-PhC guided modes, a 65 fold enhancement in the excitation is achieved in the near field region (100 nm deep and 1 microm wide) of the resonant mode. Such large enhancement together with the high spatial resolution makes this device an excellent substrate for fluorescence microscopies. PMID:20389379

Estrada, L C; Martinez, O E; Brunstein, M; Bouchoule, S; Le-Gratiet, L; Talneau, A; Sagnes, I; Monnier, P; Levenson, J A; Yacomotti, A M

2010-02-15

388

Site-Specific Labeling of Proteins in Living Cells Using Synthetic Fluorescent Dyes  

Microsoft Academic Search

\\u000a Fluorescent probes provide the inroads to the territory of modern cellular imaging. Recent developments in microscopy have\\u000a sparked the application of new optical properties of fluorescent probes. Even though the palette of genetically encoded fluorophores\\u000a has dramatically expanded in recent years, synthetic probes offer a wide choice of spectral and sensing properties that can\\u000a be custom-tailored for the visualization of

Gertrude Bunt

389

Exploring chip-capillary electrophoresis-laser-induced fluorescence field-deployable platform flexibility: separations of fluorescent dyes by chip-based non-aqueous capillary electrophoresis.  

PubMed

Microfluidic chip electrophoresis (chip-CE) is a separation method that is compatible with portable and on-site analysis, however, only few commercial chip-CE systems with laser-induced fluorescence (LIF) and light emitting diode (LED) fluorescence detection are available. They are established for several application tailored methods limited to specific biopolymers (DNA, RNA and proteins), and correspondingly the range of their applications has been limited. In this work we address the lack of commercially available research-type flexible chip-CE platforms by exploring the limits of using an application-tailored system equipped with chips and methods designed for DNA separations as a generic chip-CE platform - this is a very significant issue that has not been widely studied. In the investigated Agilent Bioanalyzer chip-CE system, the fixed components are the Agilent chips and the detection (LIF at 635 nm and LEDIF at 470 nm), while the chemistry (electrolyte) and the programming of all the high voltages are flexible. Using standard DNA chips, we show that a generic CE function of the system is easily possible and we demonstrate an extension of the applicability to non-aqueous CE (NACE). We studied the chip compatibility with organic solvents (i.e. MeOH, ACN, DMF and DMSO) and demonstrated the chip compatibility with DMSO as a non-volatile and non-hazardous solvent with satisfactory stability of migration times over 50h. The generic CE capability is illustrated with separations of fluorescent basic blue dyes methylene blue (MB), toluidine blue (TB), nile blue (NB) and brilliant cresyl blue (BC). Further, the effects of the composition of the background electrolyte (BGE) on the separation were studied, including the contents of water (0-30%) and buffer composition. In background electrolytes containing typically 80 mmol/L ammonium acetate and 870 mmol/L acetic acid in 100% DMSO baseline separation of the dyes were achieved in 40s. Linearity was documented in the range of 5-28 ?mol/L, 10-100 ?mol/L, 1.56-50 nmol/L and 5-75 nmol/L (r(2) values in the range 0.974-0.999), and limit of detection (LOD) values were 90 nmol/L, 1 ?mol/L 1.4 nmol/L, and 2 nmol/L for MB, TB, NB and BC, respectively. PMID:23510955

Nuchtavorn, Nantana; Smejkal, Petr; Breadmore, Michael C; Guijt, Rosanne M; Doble, Philip; Bek, Fritz; Foret, Frantisek; Suntornsuk, Leena; Macka, Mirek

2013-04-19

390

Genetically encoded fluorescent sensors of membrane potential  

PubMed Central

Imaging activity of neurons in intact brain tissue was conceived several decades ago and, after many years of development, voltage-sensitive dyes now offer the highest spatial and temporal resolution for imaging neuronal functions in the living brain. Further progress in this field is expected from the emergent development of genetically encoded fluorescent sensors of membrane potential. These fluorescent protein (FP) voltage sensors overcome the drawbacks of organic voltage sensitive dyes such as non-specificity of cell staining and the low accessibility of the dye to some cell types. In a transgenic animal, a genetically encoded sensor could in principle be expressed specifically in any cell type and would have the advantage of staining only the cell population determined by the specificity of the promoter used to drive expression. Here we critically review the current status of these developments.

Baker, B. J.; Mutoh, H.; Dimitrov, D.; Akemann, W.; Perron, A.; Iwamoto, Y.; Jin, L.; Cohen, L. B.; Isacoff, E. Y.; Pieribone, V. A.; Hughes, T.; Knopfel, T.

2009-01-01

391

Time-resolved fluorescence and FCS studies of dye-doped DNA  

NASA Astrophysics Data System (ADS)

Fluorescence lifetime, anisotropy and intensity dependent single molecule fluorescence correlation spectroscopy (I-FCS) are used to investigate the mechanism of fluorescence saturation in a free and nucleotide bound fluorophore (NR6104) in an antioxidising ascorbate buffer. Nucleotide attachment does not appreciably affect the fluorescence lifetime of the probe and there is a decrease in the rate of intersystem crossing relative to that of triplet state deactivation. The triplet state fraction is seen to plateau at 72% (G-attached) and 80% (free fluorophore) in agreement with these observations. Measurements of translational diffusion times show no intensity dependence for excitation intensities between 1 and 105kW cm-2 and photobleaching is therefore negligible. The dominant mechanism of fluorescence saturation is thus triplet state formation. I-FCS measurements for Rhodamine 6G in water were compared with those in the ascorbate buffer. In water the triplet fraction was saturated at considerably higher powers (45% at ca. 1.5 × 103kW cm-2) than in the ascorbate buffer (55%ca. 1 1kW cm-2)

Nicolaou, N.; Marsh, R. J.; Blacker, T.; Armoogum, D. A.; Bain, A. J.

2009-08-01

392

Symplastic Transfer of Fluorescent Dyes from Mesophyll to Sieve Tube in Stripped Leaf Tissue and Partly Isolated Minor Veins of Commelina benghalensis  

PubMed Central

We have stripped small (3 × 3 mm) fields of the upper and the opposite lower epidermis of Commelina benghalensis leaves. Pectinase treatment of the resulting chlorenchyma windows produced free-lying viable minor veins with small lumps of mesophyll cells attached. These veins were still connected with the intact remainder of the leaf. Fluorescent dyes were injected into mesophyll cells or mestome sheath cells. Continuous following of the dye from the moment of injection and use of the simple vein system allowed an unhindered and precise assessment of the cell-to-cell route of dye transfer. Disodium fluorescein and Lucifer Yellow CH injected into mesophyll or mestome sheath cells readily moved to the sieve tube. This symplastic dye transfer from mesophyll to sieve tube was also observed after injection into unmacerated stripped leaf tissue. The displacement of fluorescent dyes substantiates a symplastic continuity between mesophyll and sieve tube and therefore supports the possibility of symplastic phloem loading. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

van Kesteren, W. J. P.; van der Schoot, C.; van Bel, A. J. E.

1988-01-01

393

Spectrally resolved analysis of fluorescence blinking of single dye molecules in polymers at low temperatures  

NASA Astrophysics Data System (ADS)

We present a method for the spectrally resolved analysis of fluorescence blinking of single quantum emitters. It is based on the well-known technique of repeated recording of single-molecule (SM) fluorescence excitation spectra. The potential of our approach is presented for the example of single tetra-tert-butylterrylene molecules in an amorphous polymer matrix (polyisobutylene), which exhibit fluorescence blinking at cryogenic temperatures. Measuring the spectral dependence of the blinking statistics improves the possibility to clarify the microscopic nature of the dark state(s) of the emitters. We demonstrate how the blinking statistics can be definitely attributed to conformational changes in the local environment of a SM and how the parameters of the corresponding elementary excitations can be measured. The analysis of the blinking statistics as a function of the optical excitation frequency allows us to discriminate between photo-induced and spontaneous transitions into a dark state.

Orlov, S. V.; Naumov, A. V.; Vainer, Yu. G.; Kador, Lothar

2012-11-01

394

Molecular architecture in cyanine dye aggregates at the air-water interface. Effect of monolayer composition and organization on fluorescent behavior  

SciTech Connect

The fluorescence behavior of an amphiphatic oxacyanine dye and its thiacyanine analogue has been investigated in spread monolayers at the air-water interface. J-aggregate formation as a function of area/(dye molecule) was monitored by spectral changes in pure dye monolayers and in 1:1 mixtures of dye with various fatty acid coaggregates. Simultaneously, the thermodynamic behavior of these systems was characterized by the associated surface pressure-area isotherms. In all cases, J-aggregate formation may be related to a phase transition in the isotherm. The intensity of aggregate fluorescence is found to be inversely related to the work, ..delta..W, of compression of the monolayer through the transition. Inclusion of the fatty acid coaggregate was shown to facilitate J-aggregate formation in the order stearic > elaidic > oleic. Both fluorescence and thermodynamic data indicate more extensive aggregate formation in the thiacyanine systems. Aside from the paramount role played by the chromophore-chromophore interactions in determining J-aggregate phenomena, this study suggests important contributions from dispersion forces involving the long hydrocarbon moieties. 13 refs., 10 figs.

Vaidyanathan, S.; Patterson, L.K.; Moebius, D.; Gruniger, H.R.

1985-01-31

395

Fiber opticpH sensor for the acidic range using fluorescent dye-doped sol-gel materials  

NASA Astrophysics Data System (ADS)

A plethora of new sensor technologies have emerged for chemical, biological, environmental and security applications. However, their adoption has been constrained by lack of integration of vastly different technical areas. Fiber optic chemical sensing is one such technology; a combination of spectroscopy, materials science and optical engineering. In this work, the example of an acidic pH sensor is used to individually develop these three areas and integrate them into a working device. Acidic pH is an important parameter in chemical processes, with no suitable optical alternatives. The fluorescent pH indicator 5-(and 6)-carboxydichlorofluorescein (CDCF) was doped in a sol-gel matrix. CDCF has a pKa of 4.53, making it well suited for the acidic range. MTMS and TEOS gels were developed as films with good mechanical and chemical stability. The pH state of the immobilized dye affects the ratio of the absorption peaks. The fluorescence spectrum was red shifted in the organically modified gel. The fluorescence of hybrid spin-coated thin films resembled that of TEOS gels rather than that of hybrid bulk gels. The pH response was reversible and repeatable with a dynamic range of 5 pH units. Changes in ionic strength cause hysteresis in the sensor's response, which disappears when the film surface is saturated with electrolytes. The mechanical strength of the films in air and when immersed in solution was improved by using specific aging routines. Photo-bleaching was reduced by limiting excitation time to the duration of the measurement. Sonication, organic modification and aging in pH 2 buffer reduced leaching of the dye. Solid surface energy of the gels increased with organic modification. Hybrid gels were hydrophobic, resulting in slow response times. The diffusion constant of hydronium ions was found to depend on protonation state of the indicator and ionic strength of the solution. The diffusion constant in 0%MTMS and 10%MTMS films was of the order of 10-9 cm2/s, while in 50%MTMS and 100%MTMS gels, it was of the order of 10-11 cm2/s. Sol-gel films with moderate organic modification and an appropriate aging cycle produced the effective pH sensors.

Manyam, Upendra H.

396

A Transient Diffusion Model Yields Unitary Gap Junctional Permeabilities from Images of Cell-to-Cell Fluorescent Dye Transfer Between Xenopus Oocytes  

PubMed Central

As ubiquitous conduits for intercellular transport and communication, gap junctional pores have been the subject of numerous investigations aimed at elucidating the molecular mechanisms underlying permeability and selectivity. Dye transfer studies provide a broadly useful means of detecting coupling and assessing these properties. However, given evidence for selective permeability of gap junctions and some anomalous correlations between junctional electrical conductance and dye permeability by passive diffusion, the need exists to give such studies a more quantitative basis. This article develops a detailed diffusion model describing experiments (reported separately) involving transport of fluorescent dye from a “donor” region to an “acceptor” region within a pair of Xenopus oocytes coupled by gap junctions. Analysis of transport within a single oocyte is used to determine the diffusion and binding characteristics of the cellular cytoplasm. Subsequent double-cell calculations then yield the intercellular junction permeability, which is translated into a single-channel permeability using concomitant measurements of intercellular conductance, and known single-channel conductances of gap junctions made up of specific connexins, to count channels. The preceding strategy, combined with use of a graded size series of Alexa dyes, permits a determination of absolute values of gap junctional permeability as a function of dye size and connexin type. Interpretation of the results in terms of pore theory suggests significant levels of dye-pore affinity consistent with the expected order of magnitude of typical (e.g., van der Waals) intermolecular attractions.

Nitsche, Johannes M.; Chang, Hou-Chien; Weber, Paul A.; Nicholson, Bruce J.

2004-01-01

397

Tumor detection by exogenous fluorescent dyes using new generation photo-multiplier tubes  

Microsoft Academic Search

The easy and non-destructive fluorescence method for quantification of early changes in biological tissues improves the possibilities of the clinical research and diagnostics. Developments in this area are moving very rapidly in part because of advances in the technology and in part because of the numerous successful examples which are appearing. New family of photomultiplier tubes with a high detection

Ekaterina Borisova; I. Angelov; Vanya Mantareva; D. Petrova; Peter Townsend; L. Valberg; Lachezar Avramov

2005-01-01

398

Fluorescent-dye-doped sol-gel sensor for highly sensitive carbon dioxide gas detection below atmospheric concentrations.  

PubMed

Optical fluorescence sol-gel sensors have been developed for the detection of carbon dioxide gas in the 0.03-30% range with a detection limit of 0.008% (or 80 ppm) and a quantitation limit of 0.02% (or 200 ppm) CO(2). Sol-gels were spin-coated on glass slides to create an organically modified silica-doped matrix with the 1-hydroxypyrene-3,6,8-trisulfonate (HPTS) fluorescent indicator. The luminescence intensity of the HPTS indicator (513 nm) is quenched by CO(2), which protonates the anionic form of HPTS. An ion pair technique was used to incorporate the lipophilic dye into the hydrophilic sol-gel matrix. TiO(2) particles (<5 microm diameter) were added to induce Mie scattering and increase the incident light interaction with the sensing film, thus increasing the signal-to-noise ratio. Moisture-proof overcoatings have been used to maintain a constant level of water inside the sensor films. The optical sensors are inexpensive to prepare and can be easily coupled to fiber optics for remote sensing capabilities. A fiber-optic bundle was used for the gas detection and shown to work as part of a multianalyte platform for simultaneous detection of multiple analytes. The studies reported here resulted in the development of sol-gel optical fluorescent sensors for CO(2) gas with sensitivity below that in the atmosphere (ca. 387 ppm). These sensors are a complementary approach to current FT-IR measurements for real-time carbon dioxide detection in environmental applications. PMID:20038093

Dansby-Sparks, Royce N; Jin, Jun; Mechery, Shelly J; Sampathkumaran, Uma; Owen, Thomas William; Yu, Bi Dan; Goswami, Kisholoy; Hong, Kunlun; Grant, Joseph; Xue, Zi-Ling

2010-01-15

399

High-precision recording of the action potential in isolated cardiomyocytes using the near-infrared fluorescent dye di-4-ANBDQBS  

PubMed Central

The use of voltage-sensitive fluorescent dyes (VSD) for noninvasive measurement of the action potential (AP) in isolated cells has been hindered by low-photon yield of the preparation, dye toxicity, and photodynamic damage. Here we used a new red-shifted VSD, di-4-ANBDQBS, and a fast electron-multiplied charge-coupled device camera for optical AP (OAP) recording in guinea pig cardiac myocytes. Loading di-4-ANBDQBS did not alter APs recorded with micropipette. With short laser exposures (just enough to record one OAP every 1–5 min), di-4-ANBDQBS yielded fluorescent signals with very high signal-to-background ratios (change in fluorescence on depolarization/fluorescence at resting potential: 19.2 ± 4.1%) and signal-to-noise ratios (40 ± 13.2). Quantum chemical calculations comparing the ANBDQ chromophore to the conventional ANEP chromophore showed that the higher wavelength and the greater voltage sensitivity of the former have the same electro-optical origin: a longer path for electron redistribution in the excited state. OAP closely tracked simultaneously recorded electrical APs, permitting measurement of AP duration within 1% error. Prolonged laser exposure caused progressive AP duration prolongation and instability. However, these effects were alleviated or abolished by reducing the dye concentration and by perfusion with antioxidants. Thus the presented technique provides a unique opportunity for noninvasive AP recording in single cardiomyocytes.

Spitzer, Kenneth W.; Steadman, Bruce W.; Rees, Tyler D.; Venable, Paul; Taylor, Tyson; Shibayama, Junko; Yan, Ping; Wuskell, Joseph P.; Loew, Leslie M.; Zaitsev, Alexey V.

2010-01-01

400

Efficiency of staining hair with indocyanine green  

NASA Astrophysics Data System (ADS)

The efficiency of staining hair with indocyanine green (ICG) solution depending on type of hair, natural color, staining time and other parameters was investigated. Bonding ICG with hair material occurs due to interaction between ICG molecules and keratinocyte albumin. The penetration of ICG dye into hair meets with difficulties owing to surface protective layer.

Kulyabina, Tatyana V.; Kochubey, Vyacheslav I.

2005-06-01

401

Optical tweezers and non-ratiometric fluorescent-dye-based studies of respiration in sperm mitochondria  

Microsoft Academic Search

The purpose of this study is to investigate how the mitochondrial membrane potential affects sperm motility using laser tweezers and a non-ratiometric fluorescent probe, DiOC6(3). A 1064 nm Nd:YVO4 continuous wave laser was used to trap motile sperm at a power of 450 mW in the trap spot. Using customized tracking software, the curvilinear velocity (VCL) and the escape force

Timothy Chen; Linda Z. Shi; Qingyuan Zhu; Charlie Chandsawangbhuwana; Michael W. Berns

2011-01-01

402

pH-sensitive fluorescent dye as probe for proton uptake in photosynthetic reaction centers  

Microsoft Academic Search

Isolated and purified reaction centers (RC) from Rhodobacter sphaeroides R-26.1 were solubilised in detergent with excess quinone and external electron donors and illuminated in the presence of pyranine. The pH change accompanying the reaction center photocycle was monitored by recording the variation of the pyranine fluorescence intensity. Using QB-depleted reaction centers or blocking the photocycle with terbutryne strongly reduced the

A. Agostiano; F. Mavelli; F. Milano; L. Giotta; M. Trotta; L. Nagy; P. Maroti

2004-01-01

403

In Situ Measurement of Airway Surface Liquid [K+] Using a Ratioable K+-sensitive Fluorescent Dye*  

PubMed Central

The airway surface liquid (ASL) is the thin fluid layer lining airway surface epithelial cells, whose volume and composition are tightly regulated and may be abnormal in cystic fibrosis (CF). We synthesized a two-color fluorescent dextran to measure ASL [K+], TAC-Lime-dextran-TMR, consisting of a green-fluorescing triazacryptand K+ ionophore-Bodipy conjugate, coupled to dextran, together with a red fluorescing tetramethylrhodamine reference chromophore. TAC-Lime-dextran-TMR fluorescence was K+-selective, increasing >4-fold with increasing [K+] from 0 to 40 mm. In well differentiated human airway epithelial cells, ASL [K+] was 20.8 ± 0.3 mm and decreased by inhibition of the Na+/K+ pump (ouabain), ENaC (amiloride), CF transmembrane conductance regulator (CFTRinh-172), or K+ channels (TEA or XE991). ASL [K+] was increased by forskolin but not affected by Na+/K+/2Cl? cotransporter inhibition (bumetanide). Functional and expression studies indicated the involvement of [K+] channels KCNQ1, KCNQ3, and KCNQ5 as determinants of ASL [K+]. [K+] in CF cultures was similar to that in non-CF cultures, suggesting that abnormal ASL [K+] is not a factor in CF lung disease. In intact airways, ASL [K+] was also well above extracellular [K+]: 22 ± 1 mm in pig trachea ex vivo and 16 ± 1 mm in mouse trachea in vivo. Our results provide the first noninvasive measurements of [K+] in the ASL and indicate the involvement of apical and basolateral membrane ion transporters in maintaining a high ASL [K+].

Namkung, Wan; Song, Yuanlin; Mills, Aaron D.; Padmawar, Prashant; Finkbeiner, Walter E.; Verkman, A. S.

2009-01-01

404

The styrylpyridine dye for the silane sol-gel transition studies by time-dependent fluorescence.  

PubMed

A trans-4-(p-N,N-dimethylaminostyryl)-N-vinylbenzylpyridinium chloride (vbDMASP) fluorescence probe was optimized in ground and excited state as a function of change in the microenvironment polarity, using the Amsol HyperChem program package. In the calculations, protic and aprotic solvents were used. On this basis a change in the molecule geometry after excitation, depending on the surrounding solvent, was determined. Absorption and steady-state fluorescence spectra of vbDMASP in the solvent of different polarity and in the model water-glycerol solutions were also recorded. On the basis of Stokes' shift change with the Onsager polarity scale a change in the dipole moment of the probe during transition from ground to excited state, in protic and aprotic solvents was determined. Since during the sol-gel transition of tetraethylorthosilane in the acidic environment both polarity and viscosity of the microenvironment change the vbDMASP probe was applied and fluorescence time-resolved measurements were done. On this basis the correlations between the results of time-resolved measurements for the multichromophoric probe applied in the gelation process and molecular optimization data are discussed. PMID:16890127

Jó?wik, Donata; Miller, Ewa; Wandelt, Barbara; Wysocki, Stanis?aw

2006-08-01

405

The styrylpyridine dye for the silane sol-gel transition studies by time-dependent fluorescence  

NASA Astrophysics Data System (ADS)

A trans-4-( p- N, N-dimethylaminostyryl)- N-vinylbenzylpyridinium chloride (vbDMASP) fluorescence probe was optimized in ground and excited state as a function of change in the microenvironment polarity, using the Amsol HyperChem program package. In the calculations, protic and aprotic solvents were used. On this basis a change in the molecule geometry after excitation, depending on the surrounding solvent, was determined. Absorption and steady-state fluorescence spectra of vbDMASP in the solvent of different polarity and in the model water-glycerol solutions were also recorded. On the basis of Stokes' shift change with the Onsager polarity scale a change in the dipole moment of the probe during transition from ground to excited state, in protic and aprotic solvents was determined. Since during the sol-gel transition of tetraethylorthosilane in the acidic environment both polarity and viscosity of the microenvironment change the vbDMASP probe was applied and fluorescence time-resolved measurements were done. On this basis the correlations between the results of time-resolved measurements for the multichromophoric probe applied in the gelation process and molecular optimization data are discussed.

Jó?wik, Donata; Miller, Ewa; Wandelt, Barbara; Wysocki, Stanis?aw

2006-08-01

406

Sensing of transcription factor binding via cyanine dye pair fluorescence lifetime changes  

PubMed Central

We designed and synthesized sensors for imaging transcription factor-DNA interactions using a complementary pair of 21-base pair long oligonucleotides (ODN) carrying two internucleoside phosphate-linked cyanine fluorophores that can either engage in Förster's resonance energy transfer (FRET) with fluorescence emission or assemble into a ground state quenched dimer with short fluorescence lifetimes (FL). Cyanine fluorophores were linked to ODNs within the NF-?B binding site. These sensors were tested in the presence of recombinant p50 and p65 NF-?B proteins or constitutively NF-?B activating HeLa cell lysates. By using a coherent light excitation source we followed changes in fluorescence lifetime of the donor (Cy5.5) at the donor's excitation and emission light wavelengths, as well as the acceptor (800CW or Cy7 cyanine fluorophores) in FRET mode. We observed increases of the donor lifetime in both emitting (0.08-0.15 ns) and non-emitting quenched (0.21 ns) sensors in response to protein binding. The measurements of lifetimes in FRET mode in quenched pair-carrying ODN duplex sensors showed significant differences in FL of the acceptor cyanine fluorophore between NF-?B -containing and NF-?B -free samples but not in control sensors with ODN sequences that have decreased binding affinity to NF-?B. We anticipate that the observed effects will be instrumental for developing sensors enabling non-invasive imaging in cells that undergo activation of NF-?B.

Bogdanov, Alexei; Metelev, Valeriy; Zhang, Surong; Kumar, Anand T.N.

2013-01-01

407

Evaluation of impermeant, DNA-binding dye fluorescence as a real-time readout of eukaryotic cell toxicity in a high throughput screening format.  

PubMed

Interpretation of high throughput screening (HTS) data in cell-based assays may be confounded by cytotoxic properties of screening compounds. Therefore, assessing cell toxicity in real time during the HTS process itself would be highly advantageous. Here, we investigate the potential of putatively impermeant, fluorescent,