Altered membrane dynamics of quantum dot-conjugated integrins during osteogenic differentiation of human bone marrow derived progenitor cells.
AuthorsChen H,Titushkin I,Stroscio M,Cho M
JournalBiophysical journal
PubMed ID17114225
Functionalized quantum dots offer several advantages for tracking the motion of individual molecules on the cell surface, including selective binding, precise optical identification of cell surface molecules, and detailed examination of the molecular motion without photobleaching. We have used quantum dots conjugated with integrin antibodies and performed studies to quantitatively ... More
Tuftsin binds neuropilin-1 through a sequence similar to that encoded by exon 8 of vascular endothelial growth factor.
Morphology and dynamics of clathrin/GGA1-coated carriers budding from the trans-Golgi network.
AuthorsPuertollano R, van der Wel NN, Greene LE, Eisenberg E, Peters PJ, Bonifacino JS
JournalMol Biol Cell
PubMed ID12686608
'Sorting of transmembrane proteins and their ligands at various compartments of the endocytic and secretory pathways is mediated by selective incorporation into clathrin-coated intermediates. Previous morphological and biochemical studies have shown that these clathrin-coated intermediates consist of spherical vesicles with a diameter of 60-100 nm. Herein, we report the use ... More
Transport in lymphatic capillaries. II. Microscopic velocity measurement with fluorescence photobleaching.
AuthorsBerk DA, Swartz MA, Leu AJ, Jain RK
JournalAm J Physiol
PubMed ID8769769
'Despite its relevance to the physiology of lymph formation and propulsion, the instantaneous flow velocity in single lymphatic capillaries has not been measured to date. The method of fluorescence recovery after photobleaching (FRAP) was adapted for this purpose and used to characterize flow in the lymphatic capillaries in tail skin ... More
Quantitating intracellular transport of polyplexes by spatio-temporal image correlation spectroscopy.
AuthorsKulkarni RP, Wu DD, Davis ME, Fraser SE
JournalProc Natl Acad Sci U S A
PubMed ID15897455
'Quantitatively understanding how nonviral gene delivery vectors (polyplexes) are transported inside cells is essential before they can be optimized for gene therapy and medical applications. In this study, we used spatio-temporal image correlation spectroscopy (ICS) to follow polymer-nucleic acid particles (polyplexes) of various sizes and analyze their diffusive-like and flow ... More
Effects of atrial natriuretic peptide on phagocytosis and respiratory burst in murine macrophages.
AuthorsVollmar AM, Förster R, Schulz R
JournalEur J Pharmacol
PubMed ID9042602
'Atrial natriuretic peptide (ANP) is known to affect cardiovascular physiology displaying both hormone- and neurotransmitter characteristics. However, there is increasing evidence that ANP possesses additional biological activities referring to the immune system. To further strengthen this hypothesis the effect of ANP on two major functions of macrophages, i.e., phagocytosis and ... 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
The photon counting histogram in fluorescence fluctuation spectroscopy.
AuthorsChen Y, Müller JD, So PT, Gratton E
JournalBiophys J
PubMed ID10388780
'Fluorescence correlation spectroscopy (FCS) is generally used to obtain information about the number of fluorescent particles in a small volume and the diffusion coefficient from the autocorrelation function of the fluorescence signal. Here we demonstrate that photon counting histogram (PCH) analysis constitutes a novel tool for extracting quantities from fluorescence ... More
Role of glycocalyx in leukocyte-endothelial cell adhesion.
AuthorsMulivor AW, Lipowsky HH
JournalAm J Physiol Heart Circ Physiol
PubMed ID12234777
'The binding of fluorescently labeled microspheres (FLMs, 0.1-microm diameter) coated with antibody (1a29) to ICAM-1 was studied in postcapillary venules during topical application of the chemoattractant N-formylmethionyl-leucyl-phenylalanine (fMLP). FLM adhesion to endothelial cells (ECs) increased dramatically from 50 to 150 spheres per 100-microm length of venule after superfusion of the ... More
Characterization of the calcium release domains during excitation-contraction coupling in skeletal muscle fibres.
AuthorsDiFranco M, Novo D, Vergara JL
JournalPflugers Arch
PubMed ID11907817
'The spatiotemporal properties of the Ca2+ release process in skeletal muscle fibres were determined using a confocal spot detection system. The low-affinity, fluorescent Ca2+ indicator Oregon Green 488 BAPTA-5N (OGB-5N) was used to record localized, action potential-induced fluorescence signals from consecutive locations separated by 200 nm within a single sarcomere. ... More
Thermal fluctuations of grafted microtubules provide evidence of a length-dependent persistence length.
AuthorsPampaloni F, Lattanzi G, Jonás A, Surrey T, Frey E, Florin EL
JournalProc Natl Acad Sci U S A
PubMed ID16801537
'Microtubules are hollow cylindrical structures that constitute one of the three major classes of cytoskeletal filaments. On the mesoscopic length scale of a cell, their material properties are characterized by a single stiffness parameter, the persistence length l(p). Its value, in general, depends on the microscopic interactions between the constituent ... More
Precise microinjection into skin using hollow microneedles.
AuthorsWang PM, Cornwell M, Hill J, Prausnitz MR
JournalJ Invest Dermatol
PubMed ID16484988
'Hollow needles of micron dimensions have previously been fabricated and envisioned for use with transdermal patches or infusion pumps to achieve painless delivery of drugs to the skin for local and systemic effects without the need for hypodermic needles. However, little work has been carried out to identify methods to ... More
Gridlock signalling pathway fashions the first embryonic artery.
AuthorsZhong TP, Childs S, Leu JP, Fishman MC
JournalNature
PubMed ID11700560
'Arteries and veins are morphologically, functionally and molecularly very different, but how this distinction is established during vasculogenesis is unknown. Here we show, by lineage tracking in zebrafish embryos, that angioblast precursors for the trunk artery and vein are spatially mixed in the lateral posterior mesoderm. Progeny of each angioblast, ... More
Why molecules move along a temperature gradient.
AuthorsDuhr S, Braun D
JournalProc Natl Acad Sci U S A
PubMed ID17164337
'Molecules drift along temperature gradients, an effect called thermophoresis, the Soret effect, or thermodiffusion. In liquids, its theoretical foundation is the subject of a long-standing debate. By using an all-optical microfluidic fluorescence method, we present experimental results for DNA and polystyrene beads over a large range of particle sizes, salt ... More
Central nervous system microglial cell activation and proliferation follows direct interaction with tissue-infiltrating T cell blasts.
AuthorsSedgwick JD, Ford AL, Foulcher E, Airriess R
JournalJ Immunol
PubMed ID9605131
'Central nervous system (CNS)-resident macrophages (microglia) normally express negligible or low level MHC class II, but this is up-regulated in graft-vs-host disease (GvHD), in which a sparse CNS T cell infiltrate is observed. Relative to microglia from the normal CNS, those from the GvHD-affected CNS exhibited a 5-fold up-regulation of ... More
Temporal down-regulation of Fc gamma RIII expression and Fc gamma receptor-mediated phagocytosis in human monocyte-derived macrophages induced by TNF-alpha and IL-1 beta.
AuthorsLiao G, Simon SR
JournalJ Leukoc Biol
PubMed ID8195695
'Effects of tumor necrosis factor (TNF-alpha) and interleukin-1 beta (IL-1 beta) on the expression of Fc gamma receptors (Fc gamma Rs) and on Fc gamma R-mediated phagocytosis in human monocyte-derived macrophages (MDMs) have been determined. Treatment of MDMs with TNF-alpha (400 pg/ml) or IL-1 beta (400 pg/ml) for 80 min ... More
Rapid transport of large polymeric nanoparticles in fresh undiluted human mucus.
AuthorsLai SK, O'Hanlon DE, Harrold S, Man ST, Wang YY, Cone R, Hanes J
JournalProc Natl Acad Sci U S A
PubMed ID17244708
'Nanoparticles larger than the reported mesh-pore size range (10-200 nm) in mucus have been thought to be much too large to undergo rapid diffusional transport through mucus barriers. However, large nanoparticles are preferred for higher drug encapsulation efficiency and the ability to provide sustained delivery of a wider array of ... More
Cholesterol-dependent partitioning of PtdIns(4,5)P2 into membrane domains by the N-terminal fragment of NAP-22 (neuronal axonal myristoylated membrane protein of 22 kDa).
AuthorsEpand RM, Vuong P, Yip CM, Maekawa S, Epand RF
JournalBiochem J
PubMed ID14989697
A myristoylated peptide corresponding to the N-terminus of NAP-22 (neuronal axonal myristoylated membrane protein of 22 kDa) causes the quenching of the fluorescence of BODIPY-TMR-labelled PtdIns(4,5) P2 in bilayers of 1-palmitoyl-2-oleoyl phosphatidylcholine containing 40 mol% cholesterol and 0.1 mol% BODIPY-PtdIns(4,5)2. Both fluorescence spectroscopy and total internal reflectance fluorescence microscopy revealed ... More
Regulation of phagosome maturation by signals from toll-like receptors.
AuthorsBlander JM, Medzhitov R
JournalScience
PubMed ID15143282
In higher metazoans, phagocytosis is essential in host defense against microbial pathogens and in clearance of apoptotic cells. Both microbial and apoptotic cells are delivered on a common route from phagosomes to lysosomes for degradation. Here, we found that activation of the Toll-like receptor (TLR) signaling pathway by bacteria, but ... More
Oligomeric tubulin in large transporting complex is transported via kinesin in squid giant axons.
AuthorsTerada S, Kinjo M, Hirokawa N
JournalCell
PubMed ID11051554
Slow axonal transport depends on an active mechanism that conveys cytosolic proteins. To investigate its molecular mechanism, we now constructed an in vitro experimental system for observation of tubulin transport, using squid giant axons. After injecting fluorescence-labeled tubulin into the axons, we monitored the movement of fluorescence by confocal laser ... More
Optical detection and charge-state analysis of MALDI-generated particles with molecular masses larger than 5 MDa.
AuthorsCai Y, Peng WP, Kuo SJ, Sabu S, Han CC, Chang HC
JournalAnal Chem
PubMed ID12236352
Charged polystyrene nanoparticles are generated by matrix-assisted laser desorption/ionization (MALDI) and detected by laser-induced fluorescence (LIF) in a quadrupole ion trap. Employing the LIF technique, observations of individual fluorescent nanospheres (27 nm in diameter and containing 180 fluorescein dye equivalents) have been achieved with an average signal-to-noise ratio of approximately ... More
Characterization of the sensitivity of side scatter in a flow-stream waveguide flow cytometer.
AuthorsMariella RP, Huang Z, Langlois RG
JournalCytometry
PubMed ID10486529
BACKGROUND: We previously reported a new optical configuration, in which both the side scatter and the fluorescence are collected using the index-guided, total internal reflection of a flow stream in air (the flow-stream waveguide). METHODS: Using a mixture of 0.202-microm and 0.093-microm diameter polystyrene beads, we have characterized the side ... More
Fluorescent microangiography (FMA): an improved tool to visualize the pulmonary microvasculature.
AuthorsDutly AE, Kugathasan L, Trogadis JE, Keshavjee SH, Stewart DJ, Courtman DW
JournalLab Invest
PubMed ID16518405
Visualization of the complex lung microvasculature and resolution of its three-dimensional architecture remains a difficult experimental challenge. We present a novel fluorescent microscopy technique to visualize both the normal and diseased pulmonary microvasculature. Physiologically relevant pulmonary perfusion conditions were applied using a low-viscosity perfusate infused under continuous airway ventilation. Intensely ... More
Collection, focusing, and metering of DNA in microchannels using addressable electrode arrays for portable low-power bioanalysis.
AuthorsShaikh FA, Ugaz VM
JournalProc Natl Acad Sci U S A
PubMed ID16551750
Although advances in microfluidic technology have enabled increasingly sophisticated biosensing and bioassay operations to be performed at the microscale, many of these applications employ such small amounts of charged biomolecules (DNA, proteins, and peptides) that they must first be preconcentrated to a detectable level. Efficient strategies for precisely handling minute ... 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
Detection of changes occurring during recovery from the dauer stage in Heterorhabditis bacteriophora.
AuthorsDolan KM, Jones JT, Burnell AM
JournalParasitology
PubMed ID12166523
Nematodes of the genus Heterorhabditis are insect parasites that are widely used as biological control agents. When conditions are unfavourable for reproduction in H. bacteriophora, a long-lived, non-feeding, survival and dispersal stage, the dauer juvenile (DJ), is formed. This DJ stage is also adapted for host finding and infection. When ... 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
Mature dendritic cell generation promoted by lysophosphatidylcholine.
AuthorsCoutant F, Perrin-Cocon L, Agaugué S, Delair T, André P, Lotteau V
JournalJ Immunol
PubMed ID12165488
During the acute phase response, the interplay between high density lipoproteins and low density lipoproteins (LDL) favors transient generation of oxidized LDL with proinflammatory activities. We hypothesized that oxidative modification of LDL is an endogenous signal for the immune system, and we have shown that oxidized LDL promotes mature dendritic ... More
k-Space image correlation spectroscopy: a method for accurate transport measurements independent of fluorophore photophysics.
AuthorsKolin DL, Ronis D, Wiseman PW
JournalBiophys J
PubMed ID16861272
We present the theory and application of reciprocal space image correlation spectroscopy (kICS). This technique measures the number density, diffusion coefficient, and velocity of fluorescently labeled macromolecules in a cell membrane imaged on a confocal, two-photon, or total internal reflection fluorescence microscope. In contrast to r-space correlation techniques, we show ... More
Effect of lentinan and mannan on phagocytosis of fluorescent latex microbeads by mouse peritoneal macrophages: a flow cytometric study.
AuthorsAbel G, Szöllösi J, Chihara G, Fachet J
JournalInt J Immunopharmacol
PubMed ID2807634
Lentinan, an immunopotentiating beta-1,3-glucan polysaccharide stimulated the in vitro phagocytosis of BSA-coated, C3b- or monoclonal immunoglobulin (IgG2b)-coated fluorescent microspheres by resident or thioglycollate-elicited mouse macrophages in a dose-dependent manner. Analysis of flow cytometric data has shown that microbead phagocytosis of resident macrophages, which exhibit a lower basic phagocytic activity than ... More
Nucleolar assembly of the rRNA processing machinery in living cells.
AuthorsSavino TM, Gébrane-Younès J, De Mey J, Sibarita JB, Hernandez-Verdun D
JournalJ Cell Biol
PubMed ID11381093
To understand how nuclear machineries are targeted to accurate locations during nuclear assembly, we investigated the pathway of the ribosomal RNA (rRNA) processing machinery towards ribosomal genes (nucleolar organizer regions [NORs]) at exit of mitosis. To follow in living cells two permanently transfected green fluorescence protein-tagged nucleolar proteins, fibrillarin and ... More
Differentiation of monocytic cell clones into CD8 alpha+ dendritic cells (DC) suggests that monocytes can be direct precursors for both CD8 alpha+ and CD8 alpha- DC in the mouse.
AuthorsGao JX, Liu X, Wen J, Zhang H, Durbin J, Liu Y, Zheng P
JournalJ Immunol
PubMed ID12794119
Dendritic cells (DC) are the professional APCs that initiate T cell immune responses. DC can develop from both myeloid and lymphoid progenitors. In the mouse, the CD8alpha(+) DC had been designated as "lymphoid" DC, and CD8alpha(-) DC as "myeloid" DC until recently when it was demonstrated that common myeloid progenitors ... More
Computer image analysis method for rapid quantitation of macrophage phagocytosis.
AuthorsOdeyale CO, Hook GR
JournalJ Leukoc Biol
PubMed ID2121881
A new method is described for rapidly quantitating phagocytosis by adherent macrophages in culture using computer image analysis (CIA) of video light microscopic images. Ingestion of fluorescent microspheres by peritoneal murine macrophages is used to model phagocytosis. The grey levels of digital phase contrast and fluorescent microscopic images are used ... More
Performance comparison between the high-speed Yokogawa spinning disc confocal system and single-point scanning confocal systems.
AuthorsWang E, Babbey CM, Dunn KW
JournalJ Microsc
PubMed ID15857376
Fluorescence microscopy of the dynamics of living cells presents a special challenge to a microscope imaging system, simultaneously requiring both high spatial resolution and high temporal resolution, but with illumination levels low enough to prevent fluorophore damage and cytotoxicity. We have compared the high-speed Yokogawa CSU10 spinning disc confocal system ... More
Macrophage-enriched myristoylated alanine-rich C kinase substrate and its phosphorylation is required for the phorbol ester-stimulated diffusion of beta 2 integrin molecules.
AuthorsZhou X, Li J
JournalJ Biol Chem
PubMed ID10779523
An early event of beta(2) integrin activation is the increased diffusion rate of this molecule on the cell surface, thereby providing integrin molecules with a better chance to meet the ligands. The activation of protein kinase C (PKC) stimulates integrin diffusion by releasing the cytoskeletal constraint on integrin molecules. We ... More
Spatially correlated fluorescence/AFM of individual nanosized particles and biomolecules.
AuthorsKolodny LA, Willard DM, Carillo LL, Nelson MW, Van Orden A
JournalAnal Chem
PubMed ID11354476
Individual fluorescent polystyrene nanospheres (<10-100-nm diameter) and individual fluorescently labeled DNA molecules were dispersed on mica and analyzed using time-resolved fluorescence spectroscopy and atomic force microscopy (AFM). Spatial correlation of the fluorescence and AFM measurements was accomplished by (1) positioning a single fluorescent particle into the near diffraction-limited confocal excitation ... More
Deregulation of collagen phagocytosis in aging human fibroblasts: effects of integrin expression and cell cycle.
AuthorsLee W, McCulloch CA
JournalExp Cell Res
PubMed ID9434634
Intracellular degradation of collagen by phagocytosis in fibroblasts is essential for physiological remodeling of the extracellular matrix in a wide variety of connective tissues but imbalances between degradation and synthesis can lead to loss of tissue collagen. As aging is associated with loss of dermal and periodontal collagen and with ... More
Critical role of the alpha 4 integrin/VCAM-1 pathway in cerebral leukocyte trafficking in lupus-prone MRL/fas(lpr) mice.
AuthorsJames WG, Bullard DC, Hickey MJ
JournalJ Immunol
PubMed ID12496439
MRL/fas(lpr) mice are affected by a systemic autoimmune disease that results in leukocyte recruitment to a wide range of vascular beds, including the cerebral microvasculature. The mechanisms responsible for the leukocyte trafficking to the brain in these animals are not known. Therefore, the aim of this study was to directly ... More