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Full-Text Articles in Life Sciences

Light-Evoked Calcium Responses Of Isolated Melanopsin- Expressing Retinal Ganglion Cells, Andrew T. E. Hartwick, Jayne R. Bramley, Jianing Yu, Kelly T. Stevens, Charles N. Allen, William H. Baldridge, Patricia J. Sollars, Gary E. Pickard Dec 2007

Light-Evoked Calcium Responses Of Isolated Melanopsin- Expressing Retinal Ganglion Cells, Andrew T. E. Hartwick, Jayne R. Bramley, Jianing Yu, Kelly T. Stevens, Charles N. Allen, William H. Baldridge, Patricia J. Sollars, Gary E. Pickard

School of Veterinary and Biomedical Sciences: Faculty Publications

A small number (<2%) of mammalian retinal ganglion cells express the photopigment melanopsin and are intrinsically photosensitive (ipRGCs). Light depolarizes ipRGCs and increases intracellular calcium levels ( [Ca2+]i ) but the signaling cascades underlying these responses have yet to be elucidated. To facilitate physiological studies on these rare photoreceptors, highly enriched ipRGC cultures from neonatal rats were generated using anti-melanopsin-mediated plate adhesion (immunopanning). This novel approach enabled experiments on isolated ipRGCs, eliminating the potential confounding influence of rod/cone-driven input. Light induced a rise in [Ca2+]i (monitored using fura-2 imaging) in the immunopanned ipRGCs and the source of this Ca2+ signal was investigated. The Ca2+ responses were inhibited by 2-aminoethoxydiphenyl borate, SKF-96365 (1–2-(4-methoxyphenyl)-2-[3-(4-methoxyphenyl)propoxy]ethyl-1H-imidazole), flufenamic acid, …


Calcium Dynamics Affecting Egg Production, Skeletal Integrity, And Egg Coloration In Ring-Necked Pheasants (Phasianus Colchicus), Landon R. Jones Dec 2007

Calcium Dynamics Affecting Egg Production, Skeletal Integrity, And Egg Coloration In Ring-Necked Pheasants (Phasianus Colchicus), Landon R. Jones

Theses and Dissertations

These 4 chapters represent manuscripts formatted for submission to journals based on an experiment conducted on Ring-necked Pheasants (Phasianus colchicus). Calcium limits the distribution of this species, which produces 7-15 eggs per clutch. They may renest up to 5 times per breeding season on a diet low in calcium. The first chapter examines egg production in laying hens on 7 different diets from 0.19-4.47% calcium in the absence of calcium loading. Calcium-loaded pheasants store calcium in medullary bone before an experiment and can draw on this surplus during egg production, possibly skewing experimental results. We measured egg production, egg characteristics, …


A Conserved Cam- And Radial Spoke–Associated Complex Mediates Regulation Of Flagellar Dynein Activity, Erin E. Dymek, Elizabeth F. Smith Nov 2007

A Conserved Cam- And Radial Spoke–Associated Complex Mediates Regulation Of Flagellar Dynein Activity, Erin E. Dymek, Elizabeth F. Smith

Dartmouth Scholarship

For virtually all cilia and eukaryotic flagella, the second messengers calcium and cyclic adenosine monophosphate are implicated in modulating dynein- driven microtubule sliding to regulate beating. Calmodulin (CaM) localizes to the axoneme and is a key calcium sensor involved in regulating motility. Using immunoprecipitation and mass spectrometry, we identify members of a CaM-containing complex that are involved in regulating dynein activity. This complex includes flagellar-associated protein 91 (FAP91), which shares considerable sequence similarity to AAT-1, a protein originally identified in testis as an A-kinase anchor protein (AKAP)- binding protein. FAP91 directly interacts with radial spoke protein 3 (an AKAP), which …


Neuronal Growth Cone Dynamics Are Regulated By A Nitric Oxide-Initiated Second Messenger Pathway., Kristy Welshhans Oct 2007

Neuronal Growth Cone Dynamics Are Regulated By A Nitric Oxide-Initiated Second Messenger Pathway., Kristy Welshhans

Biology Dissertations

During development, neurons must find their way to and make connections with their appropriate targets. Growth cones are dynamic, motile structures that are integral to the establishment of appropriate connectivity during this wiring process. As growth cones migrate through their environment, they encounter guidance cues that direct their migration to their appropriate synaptic targets. The gaseous messenger nitric oxide (NO), which diffuses across the plasma membrane to act on intracellular targets, is a signaling molecule that affects growth cone motility. However, most studies have examined the effects of NO on growth cone morphology when applied in large concentrations and to …


Mechanisms For Cadmium Lumen-To-Cell Transport By The Luminal Membrane Of The Rabbit Proximal Tubule, Yanhua Wang May 2007

Mechanisms For Cadmium Lumen-To-Cell Transport By The Luminal Membrane Of The Rabbit Proximal Tubule, Yanhua Wang

Biology Dissertations

The lumen-to-cell transport, cellular accumulation, and toxicity of ionic cadmium (109Cd2+) and cadmium-cysteine conjugate (Cys-S-109Cd-S-Cys) were studied in isolated perfused S2 segments of the proximal tubule of the rabbit kidney. All perfusion solutions were HEPES buffered and contained 3H-L-glucose which functioned as a volume and leak marker along with 250 nM FD & C Green dye as a vital dye. When ionic cadmium, 0.73µM Cd2+, or 0.73µM cadmium-cysteine conjugate (Cys-S-109Cd-S-Cys) containing solution was perfused through the lumen of the tubule there was no visual evidence of toxicity such as blebbing of the luminal membrane, cellular vital dye uptake, and cellular …


Expansion Of The Calcium Hypothesis Of Brain Aging And Alzheimer's Disease: Minding The Store, Olivier Thibault, John C. Gant, Philip W. Landfield Apr 2007

Expansion Of The Calcium Hypothesis Of Brain Aging And Alzheimer's Disease: Minding The Store, Olivier Thibault, John C. Gant, Philip W. Landfield

Pharmacology and Nutritional Sciences Faculty Publications

Evidence accumulated over more than two decades has implicated Ca2+ dysregulation in brain aging and Alzheimer's disease (AD), giving rise to the Ca2+ hypothesis of brain aging and dementia. Electrophysiological, imaging, and behavioral studies in hippocampal or cortical neurons of rodents and rabbits have revealed aging-related increases in the slow afterhyperpolarization, Ca2+ spikes and currents, Ca2+transients, and L-type voltage-gated Ca2+ channel (L-VGCC) activity. Several of these changes have been associated with age-related deficits in learning or memory. Consequently, one version of the Ca2+ hypothesis has been that increased L-VGCC activity drives many of the other Ca2+-related biomarkers of hippocampal aging. …


Loss Of Alkaline Earth Elements By Runoff From Agricultural Watersheds, M. A. Elrashidi, D. Hammer, M. D. Mays, C. A. Seybold, S. D. Peaslee Apr 2007

Loss Of Alkaline Earth Elements By Runoff From Agricultural Watersheds, M. A. Elrashidi, D. Hammer, M. D. Mays, C. A. Seybold, S. D. Peaslee

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The loss of agricultural chemicals in runoff from agricultural land is a major cause of poor surface water quality in the United State. Scientists (Natural Resources Conservation Service) developed a technique using climatic, hydrologic, and soil survey information to estimate the impact of agricultural watersheds on natural water resources. The objective of this study was to apply this technique on the Wagon Train (WT) watershed to predict loss of alkaline earth elements (calcium [Ca], magnesium [Mg], barium [Ba], and strontium [Sr]) by runoff from soils and to estimate elements loading into WT reservoir. The predicted losses of Ca, Mg, Ba, …


Calcium For Extending The Shelf Life Of Fresh Whole And Minimally Processed Fruits And Vegetables, Ana Belen Martin-Diana, Daniel Rico, Jesus Maria Frias, J. Barat, Gary Henehan Jan 2007

Calcium For Extending The Shelf Life Of Fresh Whole And Minimally Processed Fruits And Vegetables, Ana Belen Martin-Diana, Daniel Rico, Jesus Maria Frias, J. Barat, Gary Henehan

Articles

The preservation of quality of fresh products is relevant for the industry due to its economic impact. This paper presents a comprehensive review of the use of different sources of calcium to preserve fresh fruits and vegetables in order to extend the shelf life and enhance the nutritional value. Emphasis is on discussing about the best sources of calcium, concentration, temperature and method of application, suitability of the commodities; and some hints for the cost/benefit analysis are presented.


Role Of Calcium And Nitric Oxide Synthase (Nos) In Brain Mitochondrial Dysfunction, Vidya Nag Nukala Jan 2007

Role Of Calcium And Nitric Oxide Synthase (Nos) In Brain Mitochondrial Dysfunction, Vidya Nag Nukala

Theses and Dissertations--Neuroscience

Mitochondria are essential for promoting cell survival and growth through aerobic metabolism and energy production. Mitochondrial function is typically analyzed using mitochondria freshly isolated from tissues and cells because they yield tightly coupled mitochondria, whereas those from frozen tissue can consist of broken mitochondria and membrane fragments. A method, utilizing a well-characterized cryoprotectant such as dimethyl sulfoxide (DMSO), is described. Such mitochondria show preserved structure and function that presents us with a possible strategy to considerably expand the time-frame and the range of biochemical, molecular and metabolic studies that can be performed without the constraints of mitochondrial longevity ex vivo …