Syntaxin 7 is localized to late endosome compartments, associates with Vamp 8, and Is required for late endosome-lysosome fusion.
AuthorsMullock BM, Smith CW, Ihrke G, Bright NA, Lindsay M, Parkinson EJ, Brooks DA, Parton RG, James DE, Luzio JP, Piper RC
JournalMol Biol Cell
PubMed ID10982406
'Protein traffic from the cell surface or the trans-Golgi network reaches the lysosome via a series of endosomal compartments. One of the last steps in the endocytic pathway is the fusion of late endosomes with lysosomes. This process has been reconstituted in vitro and has been shown to require NSF, ... More
Fractal nature of regional ventilation distribution.
AuthorsAltemeier WA, McKinney S, Glenny RW
JournalJ Appl Physiol
PubMed ID10797111
'High-resolution measurements of pulmonary perfusion reveal substantial spatial heterogeneity that is fractally distributed. This observation led to the hypothesis that the vascular tree is the principal determinant of regional blood flow. Recent studies using aerosol deposition show similar ventilation heterogeneity that is closely correlated with perfusion. We hypothesize that ventilation ... More
Mapping mechanical strain of an endogenous cytoskeletal network in living endothelial cells.
AuthorsHelmke BP, Rosen AB, Davies PF
JournalBiophys J
PubMed ID12668477
'A central aspect of cellular mechanochemical signaling is a change of cytoskeletal tension upon the imposition of exogenous forces. Here we report measurements of the spatiotemporal distribution of mechanical strain in the intermediate filament cytoskeleton of endothelial cells computed from the relative displacement of endogenous green fluorescent protein (GFP)-vimentin before ... More
Viewing dynamic assembly of molecular complexes by multi-wavelength single-molecule fluorescence.
AuthorsFriedman LJ, Chung J, Gelles J
JournalBiophys J
PubMed ID16698779
'Complexes of macromolecules that transiently self-assemble, perform a particular function, and then dissociate are a recurring theme in biology. Such systems often have a large number of possible assembly/disassembly intermediates and complex, highly branched reaction pathways. Measuring the single-step kinetic parameters in these reactions would help to identify the functionally ... More
Estimated functional diameter of alveolar septal microvessels in zone 1.
AuthorsConhaim RL, Rodenkirch LA
JournalAm J Physiol
PubMed ID8853334
'To estimate the functional diameter of alveolar septal microvessels in zone 1, we perfused isolated rat lungs with fluorescent latex particles of specific diameters (0.24, 0.49, 1.05, or 4.0 microns) at pulmonary artery pressures (Ppulmart) that were either 5 or 10 cmH2O less than the air inflation pressure (Pinflat, 25 ... More
Spatiotemporal analysis of flow-induced intermediate filament displacement in living endothelial cells.
'The distribution of hemodynamic shear stress throughout the arterial tree is transduced by the endothelium into local cellular responses that regulate vasoactivity, vessel wall remodeling, and atherogenesis. Although the exact mechanisms of mechanotransduction remain unknown, the endothelial cytoskeleton has been implicated in transmitting extracellular force to cytoplasmic sites of signal ... More
Stresses at the cell-to-substrate interface during locomotion of fibroblasts.
AuthorsDembo M, Wang YL
JournalBiophys J
PubMed ID10096925
Recent technological improvements in the elastic substrate method make it possible to produce spatially resolved measurements of the tractions exerted by single motile cells. In this study we have applied these developments to produce maps of the tractions exerted by 3T3 fibroblasts during steady locomotion. The resulting images have a ... More
Fabricating complex three-dimensional nanostructures with high-resolution conformable phase masks.
AuthorsJeon S, Park JU, Cirelli R, Yang S, Heitzman CE, Braun PV, Kenis PJ, Rogers JA
JournalProc Natl Acad Sci U S A
PubMed ID15314211
High-resolution, conformable phase masks provide a means to fabricate, in an experimentally simple manner, classes of 3D nanostructures that are technologically important but difficult to generate in other ways. In this approach, light passing through a phase mask that has features of relief comparable in dimension to the wavelength generates ... More
Rho is involved in superoxide formation during phagocytosis of opsonized zymosans.
AuthorsKim JS, Diebold BA, Kim JI, Kim J, Lee JY, Park JB
JournalJ Biol Chem
PubMed ID14970220
Phagocytosis is accompanied by the production of superoxide by the NADPH oxidase complex, for which GTP-bound Rac is essential. We wanted to determine whether Rho is also involved in the production of superoxide during phagocytosis. Inhibition of Rho by Tat-C3 exoenzyme (Tat-C3) blocked superoxide formation and curtailed the phagocytosis of ... More
Tracking single proteins within cells.
AuthorsGoulian M, Simon SM
JournalBiophys J
PubMed ID11023923
We present experiments in which single proteins were imaged and tracked within mammalian cells. Single proteins of R-phycoerythrin (RPE) were imaged by epifluorescence microscopy in the nucleoplasm and cytoplasm at 71 frames/s. We acquired two-dimensional trajectories of proteins (corresponding to the projection of three-dimensional trajectories onto the plane of focus) ... More
Translational diffusion of fluorescent proteins by molecular fourier imaging correlation spectroscopy.
AuthorsFink MC, Adair KV, Guenza MG, Marcus AH
JournalBiophys J
PubMed ID16920833
The ability to noninvasively observe translational diffusion of proteins and protein complexes is important to many biophysical problems. We report high signal/noise (>or=250) measurements of the translational diffusion in viscous solution of the fluorescent protein, DsRed. This is carried out using a new technique: molecular Fourier imaging correlation spectroscopy (M-FICS). ... More
Measurement of monomer-oligomer distributions via fluorescence moment image analysis.
AuthorsSergeev M, Costantino S, Wiseman PW
JournalBiophys J
PubMed ID16935950
We present higher-order moment analysis of fluorescence intensity fluctuations from individual laser scanning microscopy images applied to study monomer-oligomer distributions. We demonstrate that the number densities and brightness ratios of a mixed population of monomers and oligomers can be determined by analyzing higher-order moments of the fluorescence intensity fluctuations from ... More
Light transmission technique for the evaluation of colloidal transport and dynamics in porous media.
AuthorsWeisbrod N, Niemet MR, Selker JS
JournalEnviron Sci Technol
PubMed ID12953883
Colloidal transport in porous media has been typically studied in column experiments from which data analysis was limited to the evaluation of effluent breakthrough curves and/or destructive sampling at the end of the experiments. The internal processes occur within a "black box", where direct observation is not possible and therefore ... More
Primitive, crustacean-like state of blood-brain barrier in the eye of the apterygote insect Petrobius (Archaeognatha) determined from uptake of fluorescent tracers.
AuthorsShaw SR, Varney LP
JournalJ Neurobiol
PubMed ID10590170
Compound eyes of insects in 16 orders were tested for the presence of a blood-retina barrier (BRB) by injecting the hemolymph with Procion yellow, which was excluded from the eye in all Neoptera but not in two apterygotes. A primitive apterygote (Petrobius, Machilidae) was investigated further. Epifluorescence observations with small ... More
A critical role for calponin 2 in vascular development.
AuthorsTang J, Hu G, Hanai J, Yadlapalli G, Lin Y, Zhang B, Galloway J, Bahary N, Sinha S, Thisse B, Thisse C, Jin JP, Zon LI, Sukhatme VP
JournalJ Biol Chem
PubMed ID16317011
Calponin 2 (h2 calponin, CNN2) is an actin-binding protein implicated in cytoskeletal organization. We have found that the expression of calponin 2 is relatively restricted to vasculature from 16 to 30 h post-fertilization during zebrafish (Danio rerio) development. Forty-eight hours after injecting antisense morpholino oligos against calponin 2 into embryos ... More
In situ fluorescent protein imaging with metal film-enhanced total internal reflection microscopy.
AuthorsBurghardt TP, Charlesworth JE, Halstead MF, Tarara JE, Ajtai K
JournalBiophys J
PubMed ID16565065
Fluorescence detection of single molecules provides a means to investigate protein dynamics minus ambiguities introduced by ensemble averages of unsynchronized protein movement or of protein movement mimicking a local symmetry. For proteins in a biological assembly, taking advantage of the single molecule approach could require single protein isolation from within ... More
Adenovirus-mediated gene transfer to human bronchial submucosal glands using xenografts.
AuthorsPilewski JM, Engelhardt JF, Bavaria JE, Kaiser LR, Wilson JM, Albelda SM
JournalAm J Physiol
PubMed ID7733306
The cystic fibrosis (CF) transmembrane conductance regulator has been localized to both submucosal glands and surface epithelium, suggesting that both glandular and surface epithelium may be important targets for gene therapy. To determine the distribution and efficiency of recombinant adenovirus-mediated gene transfer to human airway submucosal glands, an in vivo ... More
Multiple effects on Clostridium perfringens binding, uptake and trafficking to lysosomes by inhibitors of macrophage phagocytosis receptors.
AuthorsO'Brien DK, Melville SB
JournalMicrobiology
PubMed ID12777479
Clostridium perfringens is a Gram-positive, anaerobic bacterium that is the most common cause of gas gangrene (clostridial myonecrosis) in humans. C. perfringens produces a variety of extracellular toxins that are thought to be the major virulence factors of the organism. However, C. perfringens has recently been shown to have the ... More