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Nuñez V, Upadhyayula S, Millare B, Larsen JM, Hadian A, Shin S, Vandrangi P, Gupta S, Xu H, Lin AP, Georgiev GY, Vullev VI. Microfluidic Space-Domain Time-Resolved Emission Spectroscopy of Terbium(III) and Europium(III) Chelates with Pyridine-2,6-Dicarboxylate. Anal Chem 2013; 85:4567-77. [DOI: 10.1021/ac400200x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Vicente Nuñez
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Srigokul Upadhyayula
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521,
United States
| | - Brent Millare
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Jillian M. Larsen
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Ali Hadian
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Sanghoon Shin
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Prashanthi Vandrangi
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Sharad Gupta
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Hong Xu
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Adam P. Lin
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Georgi Y. Georgiev
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Valentine I. Vullev
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521,
United States
- Department
of Chemistry, University of California,
Riverside, California 92521,
United States
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Polewski K, Zinger D, Trunk J, Sutherland JC. Ultraviolet absorption and luminescence of matrix-isolated adenine. Radiat Phys Chem Oxf Engl 1993 2011. [DOI: 10.1016/j.radphyschem.2011.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Rigbi M, Rosinski J, Siegelman HW, Sutherland JC. Cyanobacterial phycobilisomes: Selective dissociation monitored by fluorescence and circular dichroism. Proc Natl Acad Sci U S A 2010; 77:1961-5. [PMID: 16592802 PMCID: PMC348629 DOI: 10.1073/pnas.77.4.1961] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phycobilisomes are supramolecular assemblies of phycobiliproteins responsible for photosynthetic light collection in red algae and cyanobacteria. They can be selectively dissociated by reduction of temperature and buffer concentration. Phycobilisomes isolated from Fremyella diplosiphon transfer energy collected by C-phycoerythrin and C-phycocyanin to allophycocyanin. The energy transfer to allophycocyanin is nearly abolished at 2 degrees C, as indicated by a blue shift in fluorescence emission, and is accompanied by a decrease in the circular dichroism in the region of allophycocyanin absorbance. Further dissociation of the phycobilisomes can be attained by reduction of buffer concentration and holding at 2 degrees C. Energy transfer to C-phycocyanin is nearly abolished, and decreases occur in the circular dichroism in the region of C-phycocyanin and C-phycoerythrin absorbance. Complete dissociation of the phycobilisomes at low buffer concentration and 2 degrees C requires extended time. Energy transfer to C-phycocyanin is further reduced and the circular dichroism maximum of C-phycoerythrin at 575 nm is lost. Circular dichroism provides information on the hexamer-monomer transitions of the phycobiliproteins, whereas fluorescence is indicative of hexamer-hexamer interactions. We consider that hydrophobic interactions are fundamental to the maintenance of the structure and function of phycobilisomes.
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Affiliation(s)
- M Rigbi
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
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Connally R, Jin D, Piper J. High intensity solid-state UV source for time-gated luminescence microscopy. Cytometry A 2006; 69:1020-7. [PMID: 16888769 DOI: 10.1002/cyto.a.20326] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND The unique discriminative ability of immunofluorescent probes can be severely compromised when probe emission competes against naturally occurring, intrinsically fluorescent substances (autofluorophores). Luminescence microscopes that operate in the time-domain can selectively resolve probes with long fluorescence lifetimes (tau > 100 micros) against short-lived fluorescence to deliver greatly improved signal-to-noise ratio (SNR). A novel time-gated luminescence microscope design is reported that employs an ultraviolet (UV) light emitting diode (LED) to excite fluorescence from a europium chelate immunoconjugate with a long fluorescence lifetime. METHODS A commercial Zeiss epifluorescence microscope was adapted for TGL operation by fitting with a time-gated image-intensified CCD camera and a high-power (100 mW) UV LED. Capture of the luminescence was delayed for a precise interval following excitation so that autofluorescence was suppressed. Giardia cysts were labeled in situ with antibody conjugated to a europium chelate (BHHST) with a fluorescence lifetime >500 micros. RESULTS BHHST-labeled Giardia cysts emit at 617 nm when excited in the UV and were difficult to locate within the matrix of fluorescent algae using conventional fluorescence microscopy, and the SNR of probe to autofluorescent background was 0.51:1. However in time-gated luminescence mode with a gate-delay of 5 mus, the SNR was improved to 12.8:1, a 25-fold improvement. CONCLUSION In comparison to xenon flashlamps, UV LEDs are inexpensive, easily powered, and extinguish quickly. Furthermore, the spiked emission of the LED enabled removal of spectral filters from the microscope to significantly improve efficiency of fluorescence excitation and capture.
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Affiliation(s)
- Russell Connally
- Centre for Laser Applications, Division of Information and Communications Science, Department of Physics, Macquarie University, Sydney, Australia.
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Sutherland JC, Monteleone DC, Sutherland BM. Computer network for data acquisition, storage and analysis. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1997; 40:14-22. [PMID: 9301041 DOI: 10.1016/s1011-1344(97)00030-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Modern scientific instruments can produce huge quantities of data, usually in digital form. However, data acquisition is only one of three important functions. To be useful, data must also be stored and analyzed. Fortunately, the same computer-based technologies that facilitate the generation of large data-sets provide tools to accomplish these tasks. We describe a data system based on computers connected to a network, developed for this purpose.
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Affiliation(s)
- J C Sutherland
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
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Polewski K, Zinger D, Trunk J, Monteleone DC, Sutherland JC. Fluorescence of matrix isolated guanine and 7-methylguanine. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1994; 24:169-77. [PMID: 7965413 DOI: 10.1016/1011-1344(94)07018-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have prepared argon and nitrogen matrices containing guanine and 7-methylguanine, and measured their absorption, fluorescence excitation and fluorescence emission spectra. The fluorescence excitation spectrum of guanine shows four well-resolved bands in the range from 170 to 290 nm; excitation at the wavelengths of each of these bands results in a fluorescence emission with maximum intensity near 350 nm and a single-exponential decay with a lifetime of about 10 ns. There are significant differences between the fluorescent excitation and emission spectra of guanine and of 7-methylguanine, suggesting that the fluorescence observed from the guanine sample does not arise from a minority tautomer.
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Affiliation(s)
- K Polewski
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973
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Clark Sutherland J, Desmond EJ, Takacs PZ. Versatile spectrometer for experiments using synchrotron radiation at wave-lengths greater than 100 nm. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/0029-554x(80)90634-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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