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Krishnamoorthi A, Khosh Abady K, Dhankhar D, Rentzepis PM. Ultrafast Transient Absorption Spectra and Kinetics of Rod and Cone Visual Pigments. Molecules 2023; 28:5829. [PMID: 37570798 PMCID: PMC10421382 DOI: 10.3390/molecules28155829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Rods and cones are the photoreceptor cells containing the visual pigment proteins that initiate visual phototransduction following the absorption of a photon. Photon absorption induces the photochemical transformation of a visual pigment, which results in the sequential formation of distinct photo-intermediate species on the femtosecond to millisecond timescales, whereupon a visual electrical signal is generated and transmitted to the brain. Time-resolved spectroscopic studies of the rod and cone photo-intermediaries enable the detailed understanding of initial events in vision, namely the key differences that underlie the functionally distinct scotopic (rod) and photopic (cone) visual systems. In this paper, we review our recent ultrafast (picoseconds to milliseconds) transient absorption studies of rod and cone visual pigments with a detailed comparison of the transient molecular spectra and kinetics of their respective photo-intermediaries. Key results include the characterization of the porphyropsin (carp fish rhodopsin) and human green-cone opsin photobleaching sequences, which show significant spectral and kinetic differences when compared against that of bovine rhodopsin. These results altogether reveal a rather strong interplay between the visual pigment structure and its corresponding photobleaching sequence, and relevant outstanding questions that will be further investigated through a forthcoming study of the human blue-cone visual pigment are discussed.
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Affiliation(s)
- Arjun Krishnamoorthi
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Keyvan Khosh Abady
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Dinesh Dhankhar
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
- Thermo Fisher Scientific, Hillsboro, OR 97124, USA
| | - Peter M. Rentzepis
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
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Dhankhar D, Nagpal A, Tachibanaki S, Li R, Cesario TC, Rentzepis PM. Comparison of Bovine and Carp Fish Visual Pigment Photo-Intermediates at Room Temperature. Photochem Photobiol 2022; 98:1303-1311. [PMID: 35313014 DOI: 10.1111/php.13621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/17/2022] [Indexed: 11/29/2022]
Abstract
This paper presents room temperature nanoseconds to milliseconds time-resolved spectra and kinetics of the intermediate states and species of bovine and carp fish rhodopsin visual pigments, which also contained ~5% cone pigments. The nanoseconds to milliseconds range cover all the major intermediates in the visual phototransduction process except the formation of bathorhodopsin intermediate which occurs at the femtosecond time scale. The dynamics of these visual pigment intermediates are initiated by excitation with a 532 nm nanosecond laser pulse. The recorded differences between bovine and carp rhodopsin time-resolved spectra of the formation and decay kinetics of their intermediates are presented and discussed. The data show that the carp samples batho intermediate decays faster, nearly by a factor of three, compared to the bovine samples. The formation and decay spectra and kinetics of rhodopsin outer segments and extracted rhodopsin inserted in buffer solution were found to be identical, with very small differences between them in the decay lifetimes of bathorhodopsin and formation of lumirhodopsin.
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Affiliation(s)
- Dinesh Dhankhar
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA
| | - Anushka Nagpal
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA
| | - Shuji Tachibanaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Runze Li
- School of Physical Science and Technology, Shanghai Tech University, Shanghai, China
| | | | - Peter M Rentzepis
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA
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Dhankhar D, Nagpal A, Li R, Chen J, Cesario TC, Rentzepis PM. Resonance Raman Spectra for the In Situ Identification of Bacteria Strains and Their Inactivation Mechanism. Appl Spectrosc 2021; 75:1146-1154. [PMID: 33605151 DOI: 10.1177/0003702821992834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The resonance Raman spectra of bacterial carotenoids have been employed to identify bacterial strains and their intensity changes as a function of ultraviolet (UV) radiation dose have been used to differentiate between live and dead bacteria. In addition, the resonance-enhanced Raman spectra enabled us to detect bacteria in water at much lower concentrations (∼108 cells/mL) than normally detected spectroscopically. A handheld spectrometer capable of recording resonance Raman spectra in situ was designed, constructed, and was used to record the spectra. In addition to bacteria, the method presented in this paper may also be used to identify fungi, viruses, and plants, in situ, and detect infections within a very short period of time.
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Affiliation(s)
- Dinesh Dhankhar
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, USA
| | - Anushka Nagpal
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, USA
| | - Runze Li
- School of Physical Science and Technology, Shanghai Tech University, Shanghai, China
| | - Jie Chen
- Center for Ultrafast Science and Technology, Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Collaborative Innovation Center of IFSA (CICIFSA), 12474Shanghai Jiao Tong University, Shanghai, China
| | - Thomas C Cesario
- School of Medicine, University of California at Irvine, Irvine, USA
| | - Peter M Rentzepis
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, USA
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Dhankhar D, Nagpal A, Rentzepis PM. Cell-phone camera Raman spectrometer. Rev Sci Instrum 2021; 92:054101. [PMID: 34243331 DOI: 10.1063/5.0046281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/17/2021] [Indexed: 06/13/2023]
Abstract
In this report, we describe the design, construction, and operation of a cell-phone-based Raman and emission spectral detector, which when coupled to a diffraction grating and cell-phone camera system provides means for the detection, recording, and identification of chemicals, drugs, and biological molecules, in situ by means of their Raman and fluorescence spectra. The newly constructed cell-phone spectrometer system was used to record Raman spectra from various chemicals and biological molecules including the resonance enhanced Raman spectra of carrots and bacteria. In addition, we present the quantitative analysis of alcohol-water Raman spectra, performed using our cell-phone spectrometer. The designed and constructed system was also used for constructing Raman images of the samples by utilizing a position scanning stage in conjunction with the system. This compact and portable system is well suited for in situ field applications of Raman and fluorescence spectroscopy and may also be an integrated feature of future cell-phones.
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Affiliation(s)
- Dinesh Dhankhar
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Anushka Nagpal
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Peter M Rentzepis
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
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Dhankhar D, Li R, Nagpal A, Chen J, Krishnamoorthi A, Rentzepis PM. A novel approach for remote detection of bacteria using simple charge-coupled device cameras and telescope. Rev Sci Instrum 2020; 91:074106. [PMID: 32752878 DOI: 10.1063/5.0010701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
We have designed, constructed, and utilized a charge-coupled device system, integrated with a small Newtonian telescope, capable of long distance recording of bacterial fluorescence and synchronous spectra for the detection of bacteria, their component molecules, and other species. This newly developed optical system utilizes commercial monochrome cameras that we have used to detect various bacterial strains, such as Escherichia coli, and determine their concentrations. In addition, using this system, we were able to differentiate between live and dead bacteria after treatment with ultraviolet light or antibiotics.
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Affiliation(s)
- Dinesh Dhankhar
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Runze Li
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Anushka Nagpal
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Jie Chen
- Center for Ultrafast Science and Technology, Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Arjun Krishnamoorthi
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Peter M Rentzepis
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
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Li R, Elsayed-Ali HE, Chen J, Dhankhar D, Krishnamoorthi A, Rentzepis PM. Ultrafast time-resolved structural changes of thin-film ferromagnetic metal heated with femtosecond optical pulses. J Chem Phys 2019; 151:124702. [PMID: 31575190 DOI: 10.1063/1.5111578] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
As a classic ferromagnetic material, nickel has been an important research candidate used to study dynamics and interactions of electron, spin, and lattice degrees of freedom. In this study, we specifically chose a thick, 150 nm ferromagnetic nickel (111) single crystal rather than 10-20 nm thin crystals that are typically used in ultrafast studies, and we revealed both the ultrafast heating within the skin depth and the heat transfer from the surface (skin) layer to the bulk of the crystal. The lattice deformation after femtosecond laser excitation was investigated by means of 8.04 keV subpicosecond x-ray pulses, generated from a table-top laser-plasma based source. The temperature evolution of the electron, spin, and lattice was determined using a three temperature model. In addition to coherent phonon oscillations, the blast force and sonic waves, induced by the hot electron temperature gradient, were also observed by monitoring the lattice contractions during the first couple of picoseconds after laser irradiation. This study further revealed the tens of picoseconds time required for heating the hundred nanometer bulk of the Ni (111) single crystals.
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Affiliation(s)
- Runze Li
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - H E Elsayed-Ali
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529, USA
| | - Jie Chen
- Center for Ultrafast Science and Technology, Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dinesh Dhankhar
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Arjun Krishnamoorthi
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Peter M Rentzepis
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, USA
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Li R, Dhankhar D, Chen J, Cesario TC, Rentzepis PM. Determination of live:dead bacteria as a function of antibiotic treatment. J Microbiol Methods 2018; 154:73-78. [PMID: 30332616 DOI: 10.1016/j.mimet.2018.10.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 10/08/2018] [Accepted: 10/13/2018] [Indexed: 10/28/2022]
Abstract
Antibiotics are drugs that react against, kill, or inhibit the growth of bacteria. The method most often employed to evaluate the effectiveness of an antibiotic to kill bacteria requires at least 16 to 24 h for bacterial incubation. The requirement of long periods of time for the determination of the number of bacteria still alive after antibiotic treatment, may, in many cases, be detrimental to the patient's health. In addition, with increasing of bacterial antibiotic resistance, the need to utilize methods for distinguishing between live and dead bacteria within a short period of time after treatment with antibiotic agents, is becoming more crucial. To that effect, we have utilized a hand-held double monochromator to record in situ and within minutes the synchronous and normal fluorescence spectra of bacteria and other species. The fluorescence spectra of bacterial components such as tryptophan, tyrosine and DNA are clearly displayed. In addition, principal component analysis, PCA, makes it possible to display live and dead bacteria separately and determine the ratio of live:dead bacteria before and after treatment with antibiotics.
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Affiliation(s)
- Runze Li
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Dinesh Dhankhar
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Jie Chen
- Center for Ultrafast Science and Technology, Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Thomas C Cesario
- School of Medicine, University of California, Irvine, CA 92697, United States
| | - Peter M Rentzepis
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas 77843, United States.
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