Browsing by Subject "Fluorescence"
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Item Sniffer cells for the detection of neural Angiotensin II in vitro(Springer Nature, 2019-06-19) Farmer, George E.; Amune, Anna; Bachelor, Martha E.; Duong, Phong; Yuan, Joseph P.; Cunningham, J. ThomasNeuropeptide release in the brain has traditionally been difficult to observe. Existing methods lack temporal and spatial resolution that is consistent with the function and size of neurons. We use cultured "sniffer cells" to improve the temporal and spatial resolution of observing neuropeptide release. Sniffer cells were created by stably transfecting Chinese Hamster Ovary (CHO) cells with plasmids encoding the rat angiotensin type 1a receptor and a genetically encoded Ca2+ sensor. Isolated, cultured sniffer cells showed dose-dependent increases in fluorescence in response to exogenously applied angiotensin II and III, but not other common neurotransmitters. Sniffer cells placed on the median preoptic nucleus (a presumptive site of angiotensin release) displayed spontaneous activity and evoked responses to either electrical or optogenetic stimulation of the subfornical organ. Stable sniffer cell lines could be a viable method for detecting neuropeptide release in vitro, while still being able to distinguish differences in neuropeptide concentration.Item Studies on solvent induced fluorescence properties of styryl dye, LDS 798, to develop in vitro and in situ assay techniques(2011-05-01) Sarkar, Pabak; Gryczynski, ZygmuntThe styryl group of dyes has been used in cellular studies for over 50 years because of their solvatochromic and/ or electrochromic properties. Here we report characterization of solubility and solvatochromic properties of a near infra-red amiophenylstyrylquinolinum dye, styryl 11 or LDS 798. We have extended our studies to small unilamellar vesicles, lipid based nanoparticles and live cells. Our cellular studies show that LDS 798 preferentially localizes in mitochondria and its fluorescence lifetime changes with change in mitochondrial membrane potential. We have used this change in lifetime as an early marker for mitochondria-dependent apoptosis. We also found that solvatochromic properties of this dye, used in tandem with fluorescence correlation spectroscopy, can be used to efficiently determine the diffusion coefficient and hence the size of the submicron lipid based particles. This dye has the potential to provide essential information about liposomal structures and mitochondrial potential changes in vitro and in situ respectively.Item Synergy 2008: Annual Research Report(2008-01-01)