Cellular asymmetry and individuality in directional sensing.
AuthorsSamadani A, Mettetal J, van Oudenaarden A
JournalProc Natl Acad Sci U S A
PubMed ID16864788
'It is generally assumed that single cells in an isogenic population, when exposed to identical environments, exhibit the same behavior. However, it is becoming increasingly clear that, even in a genetically identical population, cellular behavior can vary significantly among cells. Here we explore this variability in the gradient-sensing response of ... More
Caged fluorescent probes.
AuthorsMitchison TJ, Sawin KE, Theriot JA, Gee K, Mallavarapu A
JournalMethods Enzymol
PubMed ID9661145
Caged compounds: photorelease technology for control of cellular chemistry and physiology.
AuthorsEllis-Davies GC
JournalNat Methods
PubMed ID17664946
Caged compounds are light-sensitive probes that functionally encapsulate biomolecules in an inactive form. Irradiation liberates the trapped molecule, permitting targeted perturbation of a biological process. Uncaging technology and fluorescence microscopy are 'optically orthogonal': the former allows control, and the latter, observation of cellular function. Used in conjunction with other technologies ... More
Effect of caged fluorescent dye on the electroosmotic mobility in microchannels.
AuthorsRoss D, Locascio LE
JournalAnal Chem
PubMed ID12641244
We report on measurements of electroosmotic mobility in polymer microchannels and silica capillaries with and without the addition of a caged fluorescein dye to the buffer. For PMMA microchannels, the mobility was found to increase from (2.6 +/- 0.1) x 10(-4) cm2 V(-1) s(-1) to (4.6 +/- 0.1) x 10(-4) ... More
Mapping fast flows over micrometer-length scales using flow-tagging velocimetry and single-molecule detection.
AuthorsShelby JP, Chiu DT,
JournalAnal Chem
PubMed ID12659200
This paper describes a technique of characterizing microfluidic flow profiles from slow laminar flow to fast near-turbulent flow. Using a photo-activated fluorophore, nanosecond-duration photolysis pulses from a Nitrogen laser, and high-sensitivity single-molecule detection with Ar+ laser excitation, we report the measurement of flow speeds up to 47 m/s in a ... More
Microfabricated arrays of femtoliter chambers allow single molecule enzymology.
AuthorsRondelez Y, Tresset G, Tabata KV, Arata H, Fujita H, Takeuchi S, Noji H
JournalNat Biotechnol
PubMed ID15723045
Precise understanding of biological functions requires tools comparable in size to the basic components of life. Single molecule studies have revealed molecular behaviors usually hidden in the ensemble- and time-averaging of bulk experiments. Although most such approaches rely on sophisticated optical strategies to limit the detection volume, another attractive approach ... More
Morphological constraints on calcium dependent glutamate receptor trafficking into individual dendritic spine.
AuthorsKorkotian E, Segal M
JournalCell Calcium
PubMed ID17187855
Glutamate receptor trafficking into dendritic spines is a pivotal step in synaptic plasticity, yet the relevance of plasticity-producing rise of [Ca2+]i and of spine morphology to subsequent delivery of glutamate receptors into dendritic spine heads are still not well understood. Following chemical induction of LTP, an increase in eGFP-GluR1 fluorescence ... More
Control of flow direction in microfluidic devices with polyelectrolyte multilayers.
AuthorsBarker SL, Ross D, Tarlov MJ, Gaitan M, Locascio LE
JournalAnal Chem
PubMed ID11140758
Electroosmotic flow (EOF) is commonly utilized in microfluidics. Because the direction of the EOF can be determined by the substrate surface charge, control of the surface chemical state offers the potential, in addition to voltage control, to direct the flow in microfluidic devices. We report the use of polyelectrolyte multilayers ... More
Laser modification of preformed polymer microchannels: application to reduce band broadening around turns subject to electrokinetic flow.
AuthorsJohnson TJ, Ross D, Gaitan M, Locascio LE
JournalAnal Chem
PubMed ID11510830
A pulsed UV excimer laser (KrF, 248 nm) was used to modify the surface charge on the side wall of hot-embossed microchannels fabricated in a poly(methyl methacrylate) substrate. Subablation level fluences, less than 2,385 mJ/cm2, were used to prevent any changes in the physical morphology of the surface. It is ... More
Flash photolysis using a light emitting diode: an efficient, compact, and affordable solution.
AuthorsBernardinelli Y, Haeberli C, Chatton JY
JournalCell Calcium
PubMed ID15862347
Flash photolysis has become an essential technique for dynamic investigations of living cells and tissues. This approach offers several advantages for instantly changing the concentration of bioactive compounds outside and inside living cells with high spatial resolution. Light sources for photolysis need to deliver pulses of high intensity light in ... More
Dynamic regulation of spine-dendrite coupling in cultured hippocampal neurons.
AuthorsKorkotian E, Holcman D, Segal M
JournalEur J Neurosci
PubMed ID15548208
We investigated the role of dendritic spine morphology in spine-dendrite calcium communication using novel experimental and theoretical approaches. A transient rise in [Ca2+]i was produced in individual spine heads of Fluo-4-loaded cultured hippocampal neurons by flash photolysis of caged calcium. Following flash photolysis in the spine head, a delayed [Ca2+]i ... More
Direct actions of nitric oxide on rat neurohypophysial K+ channels.
AuthorsAhern GP, Hsu SF, Jackson MB
JournalJ Physiol
PubMed ID10517809
1. Nitric oxide (NO) has been shown to modulate neuropeptide secretion from the posterior pituitary. Here we show that NO activates large-conductance Ca2+-activated K+ (BK) channels in posterior pituitary nerve terminals. 2. NO, generated either by the photolysis of caged-NO or with chemical donors, irreversibly enhanced the component of whole-terminal ... More
The microfluidic lighthouse: an omnidirectional gradient generator.
Authors
JournalLab Chip
PubMed ID27735954
Histology and symplasmic tracer distribution during development of barley androgenic embryos.
Authors
JournalPlanta
PubMed ID21225281
Orai1 Channels Are Essential for Amplification of Glutamate-Evoked Ca2+ Signals in Dendritic Spines to Regulate Working and Associative Memory.
Authors
JournalCell Rep
PubMed ID33264616
Wound-induced Ca2+ wave propagates through a simple release and diffusion mechanism.