Neuronal activity regulates diffusion across the neck of dendritic spines.
AuthorsBloodgood BL, Sabatini BL
JournalScience
PubMed ID16272125
'In mammalian excitatory neurons, dendritic spines are separated from dendrites by thin necks. Diffusion across the neck limits the chemical and electrical isolation of each spine. We found that spine/dendrite diffusional coupling is heterogeneous and uncovered a class of diffusionally isolated spines. The barrier to diffusion posed by the neck ... More
Diffusion coefficients in the lateral intercellular spaces of Madin-Darby canine kidney cell epithelium determined with caged compounds.
AuthorsXia P, Bungay PM, Gibson CC, Kovbasnjuk ON, Spring KR
JournalBiophys J
PubMed ID9635784
The diffusion coefficients of two caged fluorescent dyes were measured in free solution and in the lateral intercellular spaces (LIS) of cultured Madin-Darby canine kidney (MDCK) cells after photoactivation by illumination with a continuous or pulsed UV laser. Both quantitative video imaging and a new photometric method were utilized to ... More
Elucidation of a PTS-carbohydrate chemotactic signal pathway in Escherichia coli using a time-resolved behavioral assay.
AuthorsLux R, Munasinghe VR, Castellano F, Lengeler JW, Corrie JE, Khan S
JournalMol Biol Cell
PubMed ID10198062
Chemotaxis of Escherichia coli toward phosphotransferase systems (PTSs)-carbohydrates requires phosphoenolpyruvate-dependent PTSs as well as the chemotaxis response regulator CheY and its kinase, CheA. Responses initiated by flash photorelease of a PTS substrates D-glucose and its nonmetabolizable analog methyl alpha-D-glucopyranoside were measured with 33-ms time resolution using computer-assisted motion analysis. This, ... More
Diffusion of small solutes in the lateral intercellular spaces of MDCK cell epithelium grown on permeable supports.
AuthorsKovbasnjuk ON, Bungay PM, Spring KR
JournalJ Membr Biol
PubMed ID10811963
The diffusion coefficients of four solutes ranging in molecular weight from 238 to 10,000 in the lateral intercellular spaces (LIS) of cultured kidney cells (MDCK) grown on permeable supports were determined from the spread of fluorescence produced after the release of caged compounds by a pulse from a UV laser. ... More
Chemotactic responses of Escherichia coli to small jumps of photoreleased L-aspartate.
AuthorsJasuja R, Keyoung J, Reid GP, Trentham DR, Khan S
JournalBiophys J
PubMed ID10049350
Computer-assisted motion analysis coupled to flash photolysis of caged chemoeffectors provides a means for time-resolved analysis of bacterial chemotaxis. Escherichia coli taxis toward the amino acid attractant L-aspartate is mediated by the Tar receptor. The physiology of this response, as well as Tar structure and biochemistry, has been studied extensively. ... More