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Sample records for affect cell surface

  1. Nanoscale topographic changes on sterilized glass surfaces affect cell adhesion and spreading.

    PubMed

    Wittenburg, Gretel; Lauer, Günter; Oswald, Steffen; Labudde, Dirk; Franz, Clemens M

    2014-08-01

    Producing sterile glass surfaces is of great importance for a wide range of laboratory and medical applications, including in vitro cell culture and tissue engineering. However, sterilization may change the surface properties of glass and thereby affect its use for medical applications, for instance as a substrate for culturing cells. To investigate potential effects of sterilization on glass surface topography, borosilicate glass coverslips were left untreated or subjected to several common sterilization procedures, including low-temperature plasma gas, gamma irradiation and steam. Imaging by atomic force microscopy demonstrated that the surface of untreated borosilicate coverslips features a complex landscape of microislands ranging from 1000 to 3000 nm in diameter and 1 to 3 nm in height. Steam treatment completely removes these microislands, producing a nanosmooth glass surface. In contrast, plasma treatment partially degrades the microisland structure, while gamma irradiation has no effect on microisland topography. To test for possible effects of the nanotopographic structures on cell adhesion, human gingival fibroblasts were seeded on untreated or sterilized glass surfaces. Analyzing fibroblast adhesion 3, 6, and 24 h after cell seeding revealed significant differences in cell attachment and spreading depending on the sterilization method applied. Furthermore, single-cell force spectroscopy revealed a connection between the nanotopographic landscape of glass and the formation of cellular adhesion forces, indicating that fibroblasts generally adhere weakly to nanosmooth but strongly to nanorough glass surfaces. Nanotopographic changes induced by different sterilization methods may therefore need to be considered when preparing sterile glass surfaces for cell culture or biomedical applications.

  2. Surface chemical functionalities affect the behavior of human adipose-derived stem cells in vitro

    NASA Astrophysics Data System (ADS)

    Liu, Xujie; Feng, Qingling; Bachhuka, Akash; Vasilev, Krasimir

    2013-04-01

    This study examines the effect of surface chemical functionalities on the behavior of human adipose-derived stem cells (hASCs) in vitro. Plasma polymerized films rich in amine (sbnd NH2), carboxyl (sbnd COOH) and methyl (sbnd CH3), were generated on hydroxyapatite (HAp) substrates. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy (XPS). The ability of different substrates to absorb proteins was evaluated. The results showed that substrates modified with hydrophilic functional group (sbnd COOH and sbnd NH2) can absorb more proteins than these modified with more hydrophobic functional group (sbnd CH3). The behavior of human adipose-derived stem cells (hASCs) cultured on different substrates was investigated in vitro: cell counting kit-8 (CCK-8) analysis was used to characterize cell proliferation, scanning electronic microscopy (SEM) analysis was used to characterize cell morphology and alkaline phosphatase (ALP) activity analysis was used to account for differentiation. The results of this study demonstrated that the sbnd NH2 modified surfaces encourage osteogenic differentiation; the sbnd COOH modified surfaces promote cell adhesion and spreading and the sbnd CH3 modified surfaces have the lowest ability to induce osteogenic differentiation. These findings confirmed that the surface chemical states of biomaterials can affect the behavior of hASCs in vitro.

  3. Role of surface recombination in affecting the efficiency of nanostructured thin-film solar cells.

    PubMed

    Da, Yun; Xuan, Yimin

    2013-11-01

    Nanostructured light trapping is a promising way to improve the efficiency in thin-film solar cells recently. In this work, both the optical and electrical properties of thin-film solar cells with 1D periodic grating structure are investigated by using photoelectric coupling model. It is found that surface recombination plays a key role in determining the performance of nanostructured thin-film solar cells. Once the recombination effect is considered, the higher optical absorption does not mean the higher conversion efficiency as most existing publications claimed. Both the surface recombination velocity and geometric parameters of structure have great impact on the efficiency of thin-film solar cells. Our simulation results indicate that nanostructured light trapping will not only improve optical absorption but also boost the surface recombination simultaneously. Therefore, we must get the tradeoffs between optical absorption and surface recombination to obtain the maximum conversion efficiency. Our work makes it clear that both the optical absorption and electrical recombination response should be taken into account simultaneously in designing the nanostructured thin-film solar cells.

  4. Cell surface localization of importin α1/KPNA2 affects cancer cell proliferation by regulating FGF1 signalling

    PubMed Central

    Yamada, Kohji; Miyamoto, Yoichi; Tsujii, Akira; Moriyama, Tetsuji; Ikuno, Yudai; Shiromizu, Takashi; Serada, Satoshi; Fujimoto, Minoru; Tomonaga, Takeshi; Naka, Tetsuji; Yoneda, Yoshihiro; Oka, Masahiro

    2016-01-01

    Importin α1 is involved in nuclear import as a receptor for proteins with a classical nuclear localization signal (cNLS). Here, we report that importin α1 is localized to the cell surface in several cancer cell lines and detected in their cultured medium. We also found that exogenously added importin α1 is associated with the cell membrane via interaction with heparan sulfate. Furthermore, we revealed that the cell surface importin α1 recognizes cNLS-containing substrates. More particularly, importin α1 bound directly to FGF1 and FGF2, secreted cNLS-containing growth factors, and addition of exogenous importin α1 enhanced the activation of ERK1/2, downstream targets of FGF1 signalling, in FGF1-stimulated cancer cells. Additionally, anti-importin α1 antibody treatment suppressed the importin α1−FGF1 complex formation and ERK1/2 activation, resulting in decreased cell growth. This study provides novel evidence that functional importin α1 is located at the cell surface, where it accelerates the proliferation of cancer cells. PMID:26887791

  5. Surface waves affect frontogenesis

    NASA Astrophysics Data System (ADS)

    Suzuki, Nobuhiro; Fox-Kemper, Baylor; Hamlington, Peter E.; Van Roekel, Luke P.

    2016-05-01

    This paper provides a detailed analysis of momentum, angular momentum, vorticity, and energy budgets of a submesoscale front undergoing frontogenesis driven by an upper-ocean, submesoscale eddy field in a Large Eddy Simulation (LES). The LES solves the wave-averaged, or Craik-Leibovich, equations in order to account for the Stokes forces that result from interactions between nonbreaking surface waves and currents, and resolves both submesoscale eddies and boundary layer turbulence down to 4.9 m × 4.9 m × 1.25 m grid scales. It is found that submesoscale frontogenesis differs from traditional frontogenesis theory due to four effects: Stokes forces, momentum and kinetic energy transfer from submesoscale eddies to frontal secondary circulations, resolved turbulent stresses, and unbalanced torque. In the energy, momentum, angular momentum, and vorticity budgets for the frontal overturning circulation, the Stokes shear force is a leading-order contributor, typically either the second or third largest source of frontal overturning. These effects violate hydrostatic and thermal wind balances during submesoscale frontogenesis. The effect of the Stokes shear force becomes stronger with increasing alignment of the front and Stokes shear and with a nondimensional scaling. The Stokes shear force and momentum transfer from submesoscale eddies significantly energize the frontal secondary circulation along with the buoyancy.

  6. The post-translational modification of the Clostridium difficile flagellin affects motility, cell surface properties and virulence

    PubMed Central

    Faulds-Pain, Alexandra; Twine, Susan M; Vinogradov, Evgeny; Strong, Philippa C R; Dell, Anne; Buckley, Anthony M; Douce, Gillian R; Valiente, Esmeralda; Logan, Susan M; Wren, Brendan W

    2014-01-01

    Clostridium difficile is a prominent nosocomial pathogen, proliferating and causing enteric disease in individuals with a compromised gut microflora. We characterized the post-translational modification of flagellin in C. difficile 630. The structure of the modification was solved by nuclear magnetic resonance and shown to contain an N-acetylglucosamine substituted with a phosphorylated N-methyl-l-threonine. A reverse genetics approach investigated the function of the putative four-gene modification locus. All mutants were found to have truncated glycan structures by LC-MS/MS, taking into account bioinformatic analysis, we propose that the open reading frame CD0241 encodes a kinase involved in the transfer of the phosphate to the threonine, the CD0242 protein catalyses the addition of the phosphothreonine to the N-acetylglucosamine moiety and CD0243 transfers the methyl group to the threonine. Some mutations affected motility and caused cells to aggregate to each other and abiotic surfaces. Altering the structure of the flagellin modification impacted on colonization and disease recurrence in a murine model of infection, showing that alterations in the surface architecture of C. difficile vegetative cells can play a significant role in disease. We show that motility is not a requirement for colonization, but that colonization was compromised when the glycan structure was incomplete. PMID:25135277

  7. The post-translational modification of the Clostridium difficile flagellin affects motility, cell surface properties and virulence.

    PubMed

    Faulds-Pain, Alexandra; Twine, Susan M; Vinogradov, Evgeny; Strong, Philippa C R; Dell, Anne; Buckley, Anthony M; Douce, Gillian R; Valiente, Esmeralda; Logan, Susan M; Wren, Brendan W

    2014-10-01

    Clostridium difficile is a prominent nosocomial pathogen, proliferating and causing enteric disease in individuals with a compromised gut microflora. We characterized the post-translational modification of flagellin in C. difficile 630. The structure of the modification was solved by nuclear magnetic resonance and shown to contain an N-acetylglucosamine substituted with a phosphorylated N-methyl-l-threonine. A reverse genetics approach investigated the function of the putative four-gene modification locus. All mutants were found to have truncated glycan structures by LC-MS/MS, taking into account bioinformatic analysis, we propose that the open reading frame CD0241 encodes a kinase involved in the transfer of the phosphate to the threonine, the CD0242 protein catalyses the addition of the phosphothreonine to the N-acetylglucosamine moiety and CD0243 transfers the methyl group to the threonine. Some mutations affected motility and caused cells to aggregate to each other and abiotic surfaces. Altering the structure of the flagellin modification impacted on colonization and disease recurrence in a murine model of infection, showing that alterations in the surface architecture of C. difficile vegetative cells can play a significant role in disease. We show that motility is not a requirement for colonization, but that colonization was compromised when the glycan structure was incomplete. PMID:25135277

  8. Cell surface fucosylation does not affect development of colon tumors in mice with germline Smad3 mutation

    PubMed Central

    Domino, Steven E.; Karnak, David M.; Hurd, Elizabeth A.

    2006-01-01

    Background/Aims: Neoplasia-related alterations in cell surface α(1,2)fucosylated glycans have been reported in multiple tumors including colon, pancreas, endometrium, cervix, bladder, lung, and choriocarcinoma. Spontaneous colorectal tumors from mice with a germline null mutation of transforming growth factor-β signaling gene Smad3 (Madh3) were tested for α(1,2)fucosylated glycan expression. Methods: Ulex Europaeus Agglutinin-I lectin staining, fucosyltransferase gene northern blot analysis, and a cross of mutant mice with Fut2 and Smad3 germline mutations were performed. Results: Spontaneous colorectal tumors from Smad3 (-/-) homozygous null mice were found to express α(1,2)fucosylated glycans in an abnormal pattern compared to adjacent nonneoplastic colon. Northern blot analysis of α(1,2)fucosyltransferase genes Fut1 and Fut2 revealed that Fut2, but not Fut1, steady-state mRNA levels were significantly increased in tumors relative to adjacent normal colonic mucosa. Mutant mice with a Fut2-inactivating germline mutation were crossed with Smad3 targeted mice. In Smad3 (-/-)/Fut2 (-/-) double knock-out mice, UEA-I lectin staining was eliminated from colon and colon tumors, however, the number and size of tumors present by 24 weeks of age did not vary regardless of the Fut2 genotype. Conclusions: In this model of colorectal cancer, cell surface α(1,2)fucosylation does not affect development of colon tumors. PMID:17264540

  9. The Regulatory Protein RosR Affects Rhizobium leguminosarum bv. trifolii Protein Profiles, Cell Surface Properties, and Symbiosis with Clover

    PubMed Central

    Rachwał, Kamila; Boguszewska, Aleksandra; Kopcińska, Joanna; Karaś, Magdalena; Tchórzewski, Marek; Janczarek, Monika

    2016-01-01

    Rhizobium leguminosarum bv. trifolii is capable of establishing a symbiotic relationship with plants from the genus Trifolium. Previously, a regulatory protein encoded by rosR was identified and characterized in this bacterium. RosR possesses a Cys2-His2-type zinc finger motif and belongs to Ros/MucR family of rhizobial transcriptional regulators. Transcriptome profiling of the rosR mutant revealed a role of this protein in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Here, we show that a mutation in rosR resulted in considerable changes in R. leguminosarum bv. trifolii protein profiles. Extracellular, membrane, and periplasmic protein profiles of R. leguminosarum bv. trifolii wild type and the rosR mutant were examined, and proteins with substantially different abundances between these strains were identified. Compared with the wild type, extracellular fraction of the rosR mutant contained greater amounts of several proteins, including Ca2+-binding cadherin-like proteins, a RTX-like protein, autoaggregation protein RapA1, and flagellins FlaA and FlaB. In contrast, several proteins involved in the uptake of various substrates were less abundant in the mutant strain (DppA, BraC, and SfuA). In addition, differences were observed in membrane proteins of the mutant and wild-type strains, which mainly concerned various transport system components. Using atomic force microscopy (AFM) imaging, we characterized the topography and surface properties of the rosR mutant and wild-type cells. We found that the mutation in rosR gene also affected surface properties of R. leguminosarum bv. trifolii. The mutant cells were significantly more hydrophobic than the wild-type cells, and their outer membrane was three times more permeable to the hydrophobic dye N-phenyl-1-naphthylamine. The mutation of rosR also caused defects in bacterial symbiotic interaction with clover plants. Compared with

  10. The Regulatory Protein RosR Affects Rhizobium leguminosarum bv. trifolii Protein Profiles, Cell Surface Properties, and Symbiosis with Clover.

    PubMed

    Rachwał, Kamila; Boguszewska, Aleksandra; Kopcińska, Joanna; Karaś, Magdalena; Tchórzewski, Marek; Janczarek, Monika

    2016-01-01

    Rhizobium leguminosarum bv. trifolii is capable of establishing a symbiotic relationship with plants from the genus Trifolium. Previously, a regulatory protein encoded by rosR was identified and characterized in this bacterium. RosR possesses a Cys2-His2-type zinc finger motif and belongs to Ros/MucR family of rhizobial transcriptional regulators. Transcriptome profiling of the rosR mutant revealed a role of this protein in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Here, we show that a mutation in rosR resulted in considerable changes in R. leguminosarum bv. trifolii protein profiles. Extracellular, membrane, and periplasmic protein profiles of R. leguminosarum bv. trifolii wild type and the rosR mutant were examined, and proteins with substantially different abundances between these strains were identified. Compared with the wild type, extracellular fraction of the rosR mutant contained greater amounts of several proteins, including Ca(2+)-binding cadherin-like proteins, a RTX-like protein, autoaggregation protein RapA1, and flagellins FlaA and FlaB. In contrast, several proteins involved in the uptake of various substrates were less abundant in the mutant strain (DppA, BraC, and SfuA). In addition, differences were observed in membrane proteins of the mutant and wild-type strains, which mainly concerned various transport system components. Using atomic force microscopy (AFM) imaging, we characterized the topography and surface properties of the rosR mutant and wild-type cells. We found that the mutation in rosR gene also affected surface properties of R. leguminosarum bv. trifolii. The mutant cells were significantly more hydrophobic than the wild-type cells, and their outer membrane was three times more permeable to the hydrophobic dye N-phenyl-1-naphthylamine. The mutation of rosR also caused defects in bacterial symbiotic interaction with clover plants. Compared with

  11. The Regulatory Protein RosR Affects Rhizobium leguminosarum bv. trifolii Protein Profiles, Cell Surface Properties, and Symbiosis with Clover

    PubMed Central

    Rachwał, Kamila; Boguszewska, Aleksandra; Kopcińska, Joanna; Karaś, Magdalena; Tchórzewski, Marek; Janczarek, Monika

    2016-01-01

    Rhizobium leguminosarum bv. trifolii is capable of establishing a symbiotic relationship with plants from the genus Trifolium. Previously, a regulatory protein encoded by rosR was identified and characterized in this bacterium. RosR possesses a Cys2-His2-type zinc finger motif and belongs to Ros/MucR family of rhizobial transcriptional regulators. Transcriptome profiling of the rosR mutant revealed a role of this protein in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Here, we show that a mutation in rosR resulted in considerable changes in R. leguminosarum bv. trifolii protein profiles. Extracellular, membrane, and periplasmic protein profiles of R. leguminosarum bv. trifolii wild type and the rosR mutant were examined, and proteins with substantially different abundances between these strains were identified. Compared with the wild type, extracellular fraction of the rosR mutant contained greater amounts of several proteins, including Ca2+-binding cadherin-like proteins, a RTX-like protein, autoaggregation protein RapA1, and flagellins FlaA and FlaB. In contrast, several proteins involved in the uptake of various substrates were less abundant in the mutant strain (DppA, BraC, and SfuA). In addition, differences were observed in membrane proteins of the mutant and wild-type strains, which mainly concerned various transport system components. Using atomic force microscopy (AFM) imaging, we characterized the topography and surface properties of the rosR mutant and wild-type cells. We found that the mutation in rosR gene also affected surface properties of R. leguminosarum bv. trifolii. The mutant cells were significantly more hydrophobic than the wild-type cells, and their outer membrane was three times more permeable to the hydrophobic dye N-phenyl-1-naphthylamine. The mutation of rosR also caused defects in bacterial symbiotic interaction with clover plants. Compared with

  12. Factors affecting the ability of glycosylphosphatidylinositol-specific phospholipase D to degrade the membrane anchors of cell surface proteins.

    PubMed Central

    Low, M G; Huang, K S

    1991-01-01

    Mammalian serum and plasma contain high levels of glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD). Previous studies with crude serum or partially purified GPI-PLD have shown that this enzyme is capable of degrading the GPI anchor of several purified detergent-solubilized cell surface proteins yet is unable to act on GPI-anchored proteins located in intact cells. Treatment of intact ROS17/2.8, WISH or HeLa cells (or membrane fractions prepared from them) with GPI-PLD purified from bovine serum by immunoaffinity chromatography gave no detectable release of alkaline phosphatase into the medium. However, when membranes were treated with GPI-PLD in the presence of 0.1% Nonidet P-40 substantial GPI anchor degradation (as measured by Triton X-114 phase separation) was observed. The mechanism of this stimulatory effect of detergent was further investigated using [3H]myristate-labelled variant surface glycoprotein and human placental alkaline phosphatase reconstituted into phospholipid vesicles. As with the cell membranes the reconstituted substrates exhibited marked resistance to the action of purified GPI-PLD which could be overcome by the inclusion of Nonidet P-40. Similar results were obtained when crude bovine serum was used as the source of GPI-PLD. These data indicate that the resistance of cell membranes to the action of GPI-PLD is not entirely due to the action of serum or membrane-associated inhibitory factors. A more likely explanation is that, in common with many other eukaryotic phospholipases, the action of GPI-PLD is restricted by the physical state of the phospholipid bilayer in which the substrates are embedded. These data may account for the ability of endothelial and blood cells to retain GPI-anchored proteins on their surfaces in spite of the high levels of GPI-PLD present in plasma. PMID:1835378

  13. Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation.

    PubMed

    Gandolfi, Maria Giovanna; Ciapetti, Gabriela; Taddei, Paola; Perut, Francesca; Tinti, Anna; Cardoso, Marcio Vivan; Van Meerbeek, Bart; Prati, Carlo

    2010-10-01

    The effect of ageing in phosphate-containing solution of bioactive calcium-silicate cements on the chemistry, morphology and topography of the surface, as well as on in vitro human marrow stromal cells viability and proliferation was investigated. A calcium-silicate cement (wTC) mainly based on dicalcium-silicate and tricalcium-silicate was prepared. Alpha-TCP was added to wTC to obtain wTC-TCP. Bismuth oxide was inserted in wTC to prepare a radiopaque cement (wTC-Bi). A commercial calcium-silicate cement (ProRoot MTA) was tested as control. Cement disks were aged in DPBS for 5 h ('fresh samples'), 14 and 28 days, and analyzed by ESEM/EDX, SEM/EDX, ATR-FTIR, micro-Raman techniques and scanning white-light interferometry. Proliferation, LDH release, ALP activity and collagen production of human marrow stromal cells (MSC) seeded for 1-28 days on the cements were evaluated. Fresh samples exposed a surface mainly composed of calcium-silicate hydrates CSH (from the hydration of belite and alite), calcium hydroxide, calcium carbonate, and ettringite. Apatite nano-spherulites rapidly precipitated on cement surfaces within 5 h. On wTC-TCP the Ca-P deposits appeared thicker than on the other cements. Aged cements showed an irregular porous calcium-phosphate (Ca-P) coating, formed by aggregated apatite spherulites with interspersed calcite crystals. All the experimental cements exerted no acute toxicity in the cell assay system and allowed cell growth. Using biochemical results, the scores were: fresh cements>aged cements for cell proliferation and ALP activity (except for wTC-Bi), whereas fresh cementscell proliferation than aged cements, probably favoured by the presence of Si-OH gel and the early formation of apatite nano-spherulites; (2) the alpha-TCP doped cement aged for 28 days displayed the highest bioactivity and cell proliferation; (3) the deleterious effect of bismuth on cell

  14. How membrane surface affects protein structure.

    PubMed

    Bychkova, V E; Basova, L V; Balobanov, V A

    2014-12-01

    The immediate environment of the negatively charged membrane surface is characterized by decreased dielectric constant and pH value. These conditions can be modeled by water-alcohol mixtures at moderately low pH. Several globular proteins were investigated under these conditions, and their conformational behavior in the presence of phospholipid membranes was determined, as well as under conditions modeling the immediate environment of the membrane surface. These proteins underwent conformational transitions from the native to a molten globule-like state. Increased flexibility of the protein structure facilitated protein functioning. Our experimental data allow understanding forces that affect the structure of a protein functioning near the membrane surface (in other words, in the membrane field). Similar conformational states are widely reported in the literature. This indicates that the negatively charged membrane surface can serve as a moderately denaturing agent in the cell. We conclude that the effect of the membrane field on the protein structure must be taken into account.

  15. THE SIZE AND SURFACE COATING OF NANOSILVER DIFFERENTIALLY AFFECTS BIOLOGICAL ACTIVITY IN BLOOD BRAIN BARRIER (RBEC4) CELLS.

    EPA Science Inventory

    Linking the physical properties of nanoparticles with differences in their biological activity is critical for understanding their potential toxicity and mode of action. The influence of aggregate size, surface coating, and surface charge on nanosilver's (nanoAg) movement through...

  16. The β1-subunit of Na+/K+-ATPase interacts with BKCa channels and affects their steady-state expression on the cell surface

    PubMed Central

    Jha, Smita; Dryer, Stuart E.

    2009-01-01

    Large conductance Ca2+- activated K+ channels (BKCa) encoded by the Slo1 gene play a role in the physiological regulation of many cell types. Here, we show that the β1 subunit of Na+/K+-ATPase (NKβ1) interacts with the cytoplasmic COOH-terminal region of Slo1 proteins. Reduced expression of endogenous NKβ1 markedly inhibits evoked BKCa currents with no apparent effect on their gating. In addition, NKβ1 down-regulated cells show decreased density of Slo1 subunits on the cell surface. PMID:19729011

  17. TGN38/41 recycles between the cell surface and the TGN: brefeldin A affects its rate of return to the TGN.

    PubMed Central

    Reaves, B; Horn, M; Banting, G

    1993-01-01

    TGN38 and TGN41 are isoforms of an integral membrane protein (TGN38/41) that is predominantly localized to the trans-Golgi network (TGN) of normal rat kidney cells. Polyclonal antisera to TGN38/41 have been used to monitor its appearance at, and removal from, the surface of control and Brefeldin A (BFA)-treated cells. Antibodies that recognize the lumenal domain of TGN38/41 are capable of specific binding to the surface of both control and BFA-treated cells. In both control and BFA-treated cells internalized TGN38/41 is targeted to the TGN; however, there are differences in 1) the morphology of the intracellular structures through which TGN38/41 passes and 2) the kinetics of internalization. These data demonstrate that TGN38/41 cycles between the plasma membrane and the TGN in control and BFA-treated cells and suggest that recycling pathways between the plasma membrane and the TGN exist for predominantly TGN proteins as well as those that normally cycle to other intracellular compartments. They also demonstrate that addition of BFA not only alters the morphology and localization of the TGN but also the kinetics of endocytosis. Images PMID:8443412

  18. Uptake and bio-reactivity of polystyrene nanoparticles is affected by surface modifications, ageing and LPS adsorption: in vitro studies on neural tissue cells

    NASA Astrophysics Data System (ADS)

    Murali, Kumarasamy; Kenesei, Kata; Li, Yang; Demeter, Kornél; Környei, Zsuzsanna; Madarász, Emilia

    2015-02-01

    Because of their capacity of crossing an intact blood-brain barrier and reaching the brain through an injured barrier or via the nasal epithelium, nanoparticles have been considered as vehicles to deliver drugs and as contrast materials for brain imaging. The potential neurotoxicity of nanoparticles, however, is not fully explored. Using particles with a biologically inert polystyrene core material, we investigated the role of the chemical composition of particle surfaces in the in vitro interaction with different neural cell types. PS NPs within a size-range of 45-70 nm influenced the metabolic activity of cells depending on the cell-type, but caused toxicity only at extremely high particle concentrations. Neurons did not internalize particles, while microglial cells ingested a large amount of carboxylated but almost no PEGylated NPs. PEGylation reduced the protein adsorption, toxicity and cellular uptake of NPs. After storage (shelf-life >6 months), the toxicity and cellular uptake of NPs increased. The altered biological activity of ``aged'' NPs was due to particle aggregation and due to the adsorption of bioactive compounds on NP surfaces. Aggregation by increasing the size and sedimentation velocity of NPs results in increased cell-targeted NP doses. The ready endotoxin adsorption which cannot be prevented by PEG coating, can render the particles toxic. The age-dependent changes in otherwise harmless NPs could be the important sources for variability in the effects of NPs, and could explain the contradictory data obtained with ``identical'' NPs.Because of their capacity of crossing an intact blood-brain barrier and reaching the brain through an injured barrier or via the nasal epithelium, nanoparticles have been considered as vehicles to deliver drugs and as contrast materials for brain imaging. The potential neurotoxicity of nanoparticles, however, is not fully explored. Using particles with a biologically inert polystyrene core material, we investigated the

  19. Surface properties and graphitization of polyacrylonitrile based fiber electrodes affecting the negative half-cell reaction in vanadium redox flow batteries

    NASA Astrophysics Data System (ADS)

    Langner, J.; Bruns, M.; Dixon, D.; Nefedov, A.; Wöll, Ch.; Scheiba, F.; Ehrenberg, H.; Roth, C.; Melke, J.

    2016-07-01

    Carbon felt electrodes for vanadium redox flow batteries are obtained by the graphitization of polyacrylonitrile based felts at different temperatures. Subsequently, the surface of the felts is modified via thermal oxidation at various temperatures. A single-cell experiment shows that the voltage efficiency is increased by this treatment. Electrode potentials measured with reference electrode setup show that this voltage efficiency increase is caused mainly by a reduction of the overpotential of the negative half-cell reaction. Consequently, this reaction is investigated further by cyclic voltammetry and the electrode activity is correlated with structural and surface chemical properties of the carbon fibers. By Raman, X-ray photoelectron and near edge X-ray absorption fine structure spectroscopy the role of edge sites and oxygen containing functional groups (OCFs) for the electrochemical activity are elucidated. A significant activity increase is observed in correlation with these two characteristics. The amount of OCFs is correlated with structural defects (e.g. edge sites) of the carbon fibers and therefore decreases with an increasing graphitization degree. Thus, for the same thermal oxidation temperature carbon fibers graphitized at a lower temperature show higher activities than those graphitized at a higher temperature.

  20. Intentional formation of a protein corona on nanoparticles: Serum concentration affects protein corona mass, surface charge, and nanoparticle-cell interaction.

    PubMed

    Gräfe, Christine; Weidner, Andreas; Lühe, Moritz V D; Bergemann, Christian; Schacher, Felix H; Clement, Joachim H; Dutz, Silvio

    2016-06-01

    The protein corona, which immediately is formed after contact of nanoparticles and biological systems, plays a crucial role for the biological fate of nanoparticles. In the here presented study we describe a strategy to control the amount of corona proteins which bind on particle surface and the impact of such a protein corona on particle-cell interactions. For corona formation, polyethyleneimine (PEI) coated magnetic nanoparticles (MNP) were incubated in a medium consisting of fetal calf serum (FCS) and cell culture medium. To modulate the amount of proteins bind to particles, the composition of the incubation medium was varied with regard to the FCS content. The protein corona mass was estimated and the size distribution of the participating proteins was determined by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Additionally, the zeta potential of incubated particles was measured. Human blood-brain barrier-representing cell line HBMEC was used for in vitro incubation experiments. To investigate the consequences of the FCS dependent protein corona formation on the interaction of MNP and cells flow cytometry and laser scanning microscopy were used. Zeta potential as well as SDS-PAGE clearly reveal an increase in the amount of corona proteins on MNP with increasing amount of FCS in incubation medium. For MNP incubated with lower FCS concentrations especially medium-sized proteins of molecular weights between 30kDa and 100kDa could be found within the protein corona, whereas for MNP incubated within higher FCS concentrations the fraction of corona proteins of 30kDa and less increased. The presence of the protein corona reduces the interaction of PEI-coated MNP with HBMEC cells within a 30min-incubation.

  1. Controlled surface chemistries and quantitative cell response

    NASA Astrophysics Data System (ADS)

    Plant, Anne L.

    2002-03-01

    Living cells experience a large number of signaling cues from their extracellular matrix. As a result of these inputs, a variety of intracellular signaling pathways are apparently initiated simultaneously. The vast array of alternative responses that result from the integration of these inputs suggests that it may be reasonable to look for cellular response not as an 'on' or 'off' condition but as a distribution of responses. A difficult challenge is to determine whether variations in responses from individual cells arise from the complexity of intracellular signals or are due to variations in the cell culture environment. By controlling surface chemistry so that every cell 'sees' the same chemical and physical environment, we can begin to assess how the distribution of cell response is affected strictly by changes in the chemistry of the cell culture surface. Using the gene for green fluorescent protein linked to the gene for the promoter of the extracellular matrix protein, tenascin, we can easily probe the end product in a signaling pathway that is purported to be linked to surface protein chemistry and to cell shape. Cell response to well-controlled, well-characterized, and highly reproducible surfaces prepared using soft lithography techniques are compared with more conventional ways of preparing extracellular matrix proteins for cell culture. Using fluorescence microscopy and image analysis of populations of cells on these surfaces, we probe quantitatively the relationship between surface chemistry, cell shape and variations in gene expression endpoint.

  2. Substrate elasticity affects bovine satellite cell activation kinetics in vitro.

    PubMed

    Lapin, M R; Gonzalez, J M; Johnson, S E

    2013-05-01

    Satellite cells support efficient postnatal skeletal muscle hypertrophy through fusion into the adjacent muscle fiber. Nuclear contribution allows for maintenance of the fiber myonuclear domain and proficient transcription of myogenic genes. Niche growth factors affect satellite cell biology; however, the interplay between fiber elasticity and microenvironment proteins remains largely unknown. The objective of the experiment was to examine the effects of hepatocyte growth factor (HGF) and surface elasticity on bovine satellite cell (BSC) activation kinetics in vitro. Young's elastic modulus was calculated for the semimembranosus (SM) and LM muscles of young bulls (5 d; n = 8) and adult cows (27 mo; n = 4) cattle. Results indicate that LM elasticity decreased (P < 0.05) with age; no difference in Young's modulus for the SM was noted. Bovine satellite cells were seeded atop polyacrylamide bioscaffolds with surface elasticities that mimic young bull and adult cow LM or traditional cultureware. Cells were maintained in low-serum media supplemented with 5 ng/mL HGF or vehicle only for 24 or 48 h. Activation was evaluated by proliferating cell nuclear antigen (PCNA) immunocytochemistry. Results indicate that BSC maintained on rigid surfaces were activated at 24 h and refractive to HGF supplementation. By contrast, fewer (P < 0.05) BSC had exited quiescence after 24 h of culture on surfaces reflective of either young bull (8.1 ± 1.7 kPa) or adult cow (14.6 ± 1.6 kPa) LM. Supplementation with HGF promoted activation of BSC cultured on bioscaffolds as measured by an increase (P < 0.05) in PCNA immunopositive cells. Culture on pliant surfaces affected neither activation kinetics nor numbers of Paired box 7 (Pax7) immunopositive muscle stem cells (P > 0.05). However, with increasing surface elasticity, an increase (P < 0.05) in the numbers of muscle progenitors was observed. These results confirm that biophysical and biochemical signals regulate BSC activation.

  3. The 37/67kDa laminin receptor (LR) inhibitor, NSC47924, affects 37/67kDa LR cell surface localization and interaction with the cellular prion protein

    PubMed Central

    Sarnataro, Daniela; Pepe, Anna; Altamura, Gennaro; De Simone, Imma; Pesapane, Ada; Nitsch, Lucio; Montuori, Nunzia; Lavecchia, Antonio; Zurzolo, Chiara

    2016-01-01

    The 37/67 kDa laminin receptor (LR) is a non-integrin protein, which binds both laminin-1 of the extracellular matrix and prion proteins, that hold a central role in prion diseases. The 37/67 kDa LR has been identified as interactor for the prion protein (PrPC) and to be required for pathological PrP (PrPSc) propagation in scrapie-infected neuronal cells, leading to the possibility that 37/67 kDa LR-PrPC interaction is related to the pathogenesis of prion diseases. A relationship between 37/67 kDa LR and PrPC in the presence of specific LR inhibitor compounds has not been investigated yet. We have characterized the trafficking of 37/67 kDa LR in both neuronal and non-neuronal cells, finding the receptor on the cell surface and nuclei, and identified the 67 kDa LR as the almost exclusive isoform interacting with PrPC. Here, we show that the treatment with the 37/67 kDa LR inhibitor, NSC47924, affects both the direct 37/67 kDa LR-PrPC interaction in vitro and the formation of the immunocomplex in live cells, inducing a progressive internalization of 37/67 kDa LR and stabilization of PrPC on the cell surface. These data reveal NSC47924 as a useful tool to regulate PrPC and 37/67 kDa LR trafficking and degradation, representing a novel small molecule to be tested against prion diseases. PMID:27071549

  4. Structure of the cell surface.

    PubMed

    Singer, S J

    1982-01-01

    The cell surface is the locus for many important biochemical functions of cells and for the interactions of cells with one another and with their environment. The structure of the cell surface may be thought of as three-layered, with a central plasma membrane to which certain macromolecular components are attached on the outer face (the exoskeleton) and other components on the inner face (the membrane cytoskeleton). In the last decade, the basic molecular structure of the plasma membrane has been elucidated and can be represented by the fluid mosaic model as a first approximation. The binding of specific integral proteins of the membrane to individual peripheral proteins outside or inside the cell is most likely the basis for the three-layered structure of the cell surface. Studies of the last several years on the molecular structures of these three-layered cell surfaces of cultured normal fibroblasts and of fibroblasts transformed by oncogenic viruses are beginning to shed light on the molecular mechanisms responsible for changes in cell shape, adhesiveness, and in contact inhibition of motility associated with neoplastic transformation.

  5. The human T-cell leukemia/lymphotropic virus type 1 p12I proteins bind the interleukin-2 receptor beta and gammac chains and affects their expression on the cell surface.

    PubMed Central

    Mulloy, J C; Crownley, R W; Fullen, J; Leonard, W J; Franchini, G

    1996-01-01

    p12I is a small hydrophobic protein encoded by the human T-cell leukemia/lymphotropic virus type 1 (HTLV-1) that interacts with the 16-kDa component of the H+ vacuolar ATPase and cooperates with bovine papillomavirus 1 E5 oncoprotein in cell transformation. Just as an important step in E5 action appears to be its binding to the platelet-derived growth factor receptor, it was found that p12I binds specifically to both the beta and gamma(c) chains of the interleukin-2 receptor (IL-2R). The IL-2R beta and gamma(c) chains associated with p12I are endoglycosidase-H sensitive, suggesting that their interaction occurs in a pre-Golgi compartment. p12I stabilizes the immature forms of the IL-2R beta and gamma(c) chains and decreases their cell surface expression. The interactions of p12I with IL-2R beta and gamma(c) may have important implications in the immunosuppressive effect of HTLV-1 in vivo as well as in the ligand-independent HTLV-1-mediated T-cell proliferation. PMID:8648694

  6. How surface roughness affects chemical transfer from soil to surface runoff?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil surface roughness affects transport processes, e.g., runoff generation, infiltration, sediment detachment, etc., occurring on the surface. Nevertheless, how soil roughness affects chemical transport is less known. In this study, we partitioned roughness elements into mounds which diverge water ...

  7. Activities affecting surface water resources: A general overview

    SciTech Connect

    Not Available

    1990-01-01

    In November 1987, P.E.I. signed a federal/provincial work-sharing arrangement on water resource management focusing on groundwater pollution, surface water degradation and estuarine eutrophication. The surface water program was designed to identify current surface water uses and users within 12 major watersheds across the Island containing 26 individual rivers, as well as problems arising due to practices that degrade the quality of surface water and restricts its value to other user groups. This report presents a general overview of the program, covering the general characteristics of the Island; operations in agriculture, fish and wildlife, forestry, recreation, fisheries, and industry; alterations of natural features of waterways; wetlands; additional watershed activities such as hydrometric stations and subdivision development; and activities affecting surface water resources such as sedimentation sources, pollution point sources and instream obstructions.

  8. Physical parameters affecting living cells in space

    NASA Astrophysics Data System (ADS)

    Langbein, Dieter

    The question is posed: Why does a living cell react to the absence of gravity? What sensors may it have? Does it note pressure, sedimentation, convection, or other parameters? If somewhere in a liquid volume sodium ions are replaced by potassium ions, the density of the liquid changes locally: the heavier regions sink, the lighter regions rise. This may contribute to species transport, to the metabolism. Under microgravity this mechanism is strongly reduced. On the other hand, other reasons for convection like thermal and solutal interface convection are left. Do they affect species transport? Another important effect of gravity is the hydrostatic pressure. On the macroscopic side, the pressure between our head and feet changes by 0.35 atmospheres. On the microscopic level the hydrostatic pressure on the upper half of a cell membrane is lower than on the lower half. This, by affecting the ion transport through the membrane, may change the surrounding electric potential. It has been suggested to be one of the reasons for graviperception. Following the discussion of these and other effects possibly important in life sciences in space, an order of magnitude analysis of the residual accelerations tolerable during experiments in materials sciences is outlined. In the field of life sciences only rough estimates are available at present.

  9. Substrate properties affect collective cell motion

    NASA Astrophysics Data System (ADS)

    Pegoraro, Adrian; Guo, Ming; Ehrlicher, Allen; Weitz, David

    2013-03-01

    When cells move collectively, cooperative motion, which is characterized by long range correlations in cell movement, is necessary for migration. This collective cell motion is influenced by cell-cell interactions as well as by cell-substrate coupling. Furthermore, on soft substrates it is possible for cells to mechanically couple over long distances through the substrate itself. By changing the properties of the substrate, it is possible to decouple some of these contributions and better understand the role they play in collective cell motion. We vary both the substrate stiffness and adhesion protein concentration and find changes in the collective cell motion of the cells despite only small differences in total cell density and average cell size in the confluent layers. We test these changes on polyacrylamide and PDMS substrates as well as on structured substrates made of PDMS posts that prevent mechanical coupling through the substrate while still allowing stiffness to be varied.

  10. Surface modification of layered silicates. I. Factors affecting thermal stability

    NASA Astrophysics Data System (ADS)

    Mittal, Vikas

    2012-12-01

    The resistance of modification molecules bound to montmorillonite platelet surfaces towards structural damage at high temperature is a major parameter guiding the formation of optimal interface between the filler and polymer phases in a nanocomposite material. As nanocomposites are generated by melt-blending of modified mineral and polymer, it is necessary to quantify the thermal resistance of the filler surface modification at the compounding conditions because different modifications differ in chain length, chemical structure, chain density, and thermal performance. A number of different alkyl ammonium modifications were exchanged on the montmorillonites with cation exchange capacities in the range 680-900 µequiv. g-1 and their thermal behaviour was characterised using high resolution thermogravimetric analysis. Quantitative comparisons between different modified minerals were achieved by comparing temperature at 10% weight loss as well peak degradation temperature. Various factors affecting thermal stability, such as length and density (or number) of alkyl chains in the modification, presence of excess modification molecules on the filler surface, the chemical structure of the surface modifications, etc. were studied. The TGA findings were also correlated with X-ray diffraction of the modified platelets.

  11. Surface modification of layered silicates. II. Factors affecting thermal stability

    NASA Astrophysics Data System (ADS)

    Mittal, Vikas

    2012-12-01

    Different aluminosilicates, such as montmorillonite, vermiculite and mica, were surface-treated with a variety of organic modifiers to quantify factors affecting the thermal stability of the modified fillers. Montmorillonites with different cation exchange capacities were also used. Thermal characterisation was carried out via high resolution thermogravimetric analysis and the results were correlated with X-ray diffraction measurements. Modified substrates, such as montmorillonite, vermiculite and mica, differed in their thermal behaviour even when modified with the same surface modifiers. Phosphonium-based modifiers were the most thermally stable, compared to pyridinium and ammonium ions. Mixed brushes from the modifiers also influenced the thermal behaviour of the modified substrates. When further modified using physical adsorption or chemical reactions on the surface, the modified minerals also displayed alterations in the thermal behaviour of the fillers. The results can be used as a guide for the selection of surface modifiers in the nanocomposite synthesis process where compounding of the filler with the polymer at high temperature and shear is required.

  12. Interactions between surface roughness and airflow turbulence affecting drying dynamics of rough porous surfaces

    NASA Astrophysics Data System (ADS)

    Haghighi, Erfan; Kirchner, James; Or, Dani

    2016-04-01

    Evaporative drying of porous surfaces interacting with turbulent airflows is common in various industrial and natural applications. The intrinsic relief and roughness of natural porous surfaces are likely to influence the structure of interacting turbulent airflow boundary layers, and thus affect rates and patterns of heat and vapor fluxes from the surface. These links have been formalized in new mechanistic models that consider intermittent and localized turbulence-induced boundary layers, resulting in rich surface evaporation and energy exchange dynamics. The models were evaluated experimentally by systematically varying surface roughness elements in drying experiments of wavy and bluff-body covered sand surfaces in a wind tunnel. Thermal infrared signatures of localized evaporative fluxes as well as mean evaporative mass losses were recorded. The resulting patterns were in good agreement with model predictions for local and surface averaged turbulent exchange rates. Experimental and theoretical results suggest that evaporative water losses from wavy sand surfaces can be either enhanced or suppressed (relative to a flat surface), due to the complex interplay between the local boundary layer thickness and internal limitations on water flow to the evaporating surface. For sand surfaces covered by isolated cylindrical elements (bluff bodies), model predictions and measurements show persistent enhancement of evaporative fluxes from bluff-rough surfaces compared to a flat surface under similar conditions. This enhancement is attributed to the formation of vortices that thin the boundary layer over part of the interacting surface footprint. The implications of this study for interpreting and upscaling evapotranspiration rates from terrestrial surfaces will be discussed.

  13. Culture surfaces coated with various implant materials affect chondrocyte growth and metabolism.

    PubMed

    Hambleton, J; Schwartz, Z; Khare, A; Windeler, S W; Luna, M; Brooks, B P; Dean, D D; Boyan, B D

    1994-07-01

    to culture surface was comparable, differing primarily in magnitude. Cell maturation-dependent effects were evident when enzyme activity in trypsinized and scraped cells was compared. These results indicate that different surface materials affect chondrocyte metabolism and phenotypic expression in vitro and suggest that implant materials may modulate the phenotypic expression of cells in vivo. PMID:7520486

  14. Phosphate Ions Affect the Water Structure at Functionalized Membrane Surfaces.

    PubMed

    Barrett, Aliyah; Imbrogno, Joseph; Belfort, Georges; Petersen, Poul B

    2016-09-01

    Antifouling surfaces improve function, efficiency, and safety in products such as water filtration membranes, marine vehicle coatings, and medical implants by resisting protein and biofilm adhesion. Understanding the role of water structure at these materials in preventing protein adhesion and biofilm formation is critical to designing more effective coatings. Such fouling experiments are typically performed under biological conditions using isotonic aqueous buffers. Previous studies have explored the structure of pure water at a few different antifouling surfaces, but the effect of electrolytes and ionic strength (I) on the water structure at antifouling surfaces is not well studied. Here sum frequency generation (SFG) spectroscopy is used to characterize the interfacial water structure at poly(ether sulfone) (PES) and two surface-modified PES films in contact with 0.01 M phosphate buffer with high and low salt (Ionic strength, I= 0.166 and 0.025 M, respectively). Unmodified PES, commonly used as a filtration membrane, and modified PES with a hydrophobic alkane (C18) and with a poly(ethylene glycol) (PEG) were used. In the low ionic strength phosphate buffer, water was strongly ordered near the surface of the PEG-modified PES film due to exclusion of phosphate ions and the creation of a surface potential resulting from charge separation between phosphate anions and sodium cations. However, in the high ionic strength phosphate buffer, the sodium and potassium chloride (138 and 3 mM, respectively) in the phosphate buffered saline screened this charge and substantially reduced water ordering. A much smaller water ordering and subsequent reduction upon salt addition was observed for the C18-modified PES, and little water structure change was seen for the unmodified PES. The large difference in water structuring with increasing ionic strength between widely used phosphate buffer and phosphate buffered saline at the PEG interface demonstrates the importance of studying

  15. Programming Surface Chemistry with Engineered Cells.

    PubMed

    Zhang, Ruihua; Heyde, Keith C; Scott, Felicia Y; Paek, Sung-Ho; Ruder, Warren C

    2016-09-16

    We have developed synthetic gene networks that enable engineered cells to selectively program surface chemistry. E. coli were engineered to upregulate biotin synthase, and therefore biotin synthesis, upon biochemical induction. Additionally, two different functionalized surfaces were developed that utilized binding between biotin and streptavidin to regulate enzyme assembly on programmable surfaces. When combined, the interactions between engineered cells and surfaces demonstrated that synthetic biology can be used to engineer cells that selectively control and modify molecular assembly by exploiting surface chemistry. Our system is highly modular and has the potential to influence fields ranging from tissue engineering to drug development and delivery. PMID:27203116

  16. Programming Surface Chemistry with Engineered Cells.

    PubMed

    Zhang, Ruihua; Heyde, Keith C; Scott, Felicia Y; Paek, Sung-Ho; Ruder, Warren C

    2016-09-16

    We have developed synthetic gene networks that enable engineered cells to selectively program surface chemistry. E. coli were engineered to upregulate biotin synthase, and therefore biotin synthesis, upon biochemical induction. Additionally, two different functionalized surfaces were developed that utilized binding between biotin and streptavidin to regulate enzyme assembly on programmable surfaces. When combined, the interactions between engineered cells and surfaces demonstrated that synthetic biology can be used to engineer cells that selectively control and modify molecular assembly by exploiting surface chemistry. Our system is highly modular and has the potential to influence fields ranging from tissue engineering to drug development and delivery.

  17. Proteinase production in Pseudomonas fluorescens ON2 is affected by carbon sources and allows surface-attached but not planktonic cells to utilize protein for growth in lake water.

    PubMed

    Nicolaisen, Mette H; Worm, Jakob; Jørgensen, Niels O G; Middelboe, Mathias; Nybroe, Ole

    2012-04-01

    Proteins may be an important carbon and nitrogen source to bacteria in aquatic habitats, yet knowledge on the actual utilization of this substrate by proteolytic bacteria is scarce. In this study, Pseudomonas fluorescens ON2 produced an alkaline proteinase (AprX) during growth, and there was no evidence for cell density-regulated or starvation-induced proteinase production. Proteinase was produced in the absence of an organic nitrogen source, and citrate had a negative while glucose had a positive effect on the production. Hence, P. fluorescens ON2 seems to exploit protein sources by expressing the proteinase during growth unless a preferred carbon source such as citrate is present. Lake water model systems were subsequently used to investigate the ability of proteolytic vs. nonproteolytic ON2 strains to utilize protein for growth at moderate cell densities. Only cells forming surface-attached microcolonies were able to utilize this resource, while planktonic cells were not. Our experiments are the first to experimentally support models predicting that production of extracellular enzymes in dilute environments may be a waste of resources, whereas it represents a favorable feeding strategy in organic matrices such as detritus, microcolonies, or biofilm. PMID:22224410

  18. How does cancer cell metabolism affect tumor migration and invasion?

    PubMed

    Han, Tianyu; Kang, De; Ji, Daokun; Wang, Xiaoyu; Zhan, Weihua; Fu, Minggui; Xin, Hong-Bo; Wang, Jian-Bin

    2013-01-01

    Cancer metastasis is the major cause of cancer-associated death. Accordingly, identification of the regulatory mechanisms that control whether or not tumor cells become "directed walkers" is a crucial issue of cancer research. The deregulation of cell migration during cancer progression determines the capacity of tumor cells to escape from the primary tumors and invade adjacent tissues to finally form metastases. The ability to switch from a predominantly oxidative metabolism to glycolysis and the production of lactate even when oxygen is plentiful is a key characteristic of cancer cells. This metabolic switch, known as the Warburg effect, was first described in 1920s, and affected not only tumor cell growth but also tumor cell migration. In this review, we will focus on the recent studies on how cancer cell metabolism affects tumor cell migration and invasion. Understanding the new aspects on molecular mechanisms and signaling pathways controlling tumor cell migration is critical for development of therapeutic strategies for cancer patients.

  19. Diffusing colloidal probes of cell surfaces.

    PubMed

    Duncan, Gregg A; Fairbrother, D Howard; Bevan, Michael A

    2016-05-25

    Measurements and analyses are reported to quantify dynamic and equilibrium interactions between colloidal particles and live cell surfaces using dark field video microscopy. Two-dimensional trajectories of micron-sized polyethylene glycol (PEG)-coated silica colloids relative to adherent epithelial breast cancer cell perimeters are determined allowing measurement of position dependent diffusivities and interaction potentials. PEG was chosen as the material system of interest to assess non-specific interactions with cell surfaces and establishes a basis for investigation of specific interactions in future studies. Analysis of measured potential energies on cell surfaces reveals the spatial dependence in cell topography. With the measured cell topography and models for particle-cell surface hydrodynamic interactions, excellent agreement is obtained between theoretical and measured colloidal transport on cell surfaces. Quantitative analyses of association lifetimes showed that PEG coatings act to stabilize colloids above the cell surface through net repulsive, steric interactions. Our results demonstrate a self-consistent analysis of diffusing colloidal probe interactions due to conservative and non-conservative forces to characterize biophysical cell surface properties. PMID:27117575

  20. Diffusing colloidal probes of cell surfaces.

    PubMed

    Duncan, Gregg A; Fairbrother, D Howard; Bevan, Michael A

    2016-05-25

    Measurements and analyses are reported to quantify dynamic and equilibrium interactions between colloidal particles and live cell surfaces using dark field video microscopy. Two-dimensional trajectories of micron-sized polyethylene glycol (PEG)-coated silica colloids relative to adherent epithelial breast cancer cell perimeters are determined allowing measurement of position dependent diffusivities and interaction potentials. PEG was chosen as the material system of interest to assess non-specific interactions with cell surfaces and establishes a basis for investigation of specific interactions in future studies. Analysis of measured potential energies on cell surfaces reveals the spatial dependence in cell topography. With the measured cell topography and models for particle-cell surface hydrodynamic interactions, excellent agreement is obtained between theoretical and measured colloidal transport on cell surfaces. Quantitative analyses of association lifetimes showed that PEG coatings act to stabilize colloids above the cell surface through net repulsive, steric interactions. Our results demonstrate a self-consistent analysis of diffusing colloidal probe interactions due to conservative and non-conservative forces to characterize biophysical cell surface properties.

  1. Surface-modified gold nanorods for specific cell targeting

    NASA Astrophysics Data System (ADS)

    Wang, Chan-Ung; Arai, Yoshie; Kim, Insun; Jang, Wonhee; Lee, Seonghyun; Hafner, Jason H.; Jeoung, Eunhee; Jung, Deokho; Kwon, Youngeun

    2012-05-01

    Gold nanoparticles (GNPs) have unique properties that make them highly attractive materials for developing functional reagents for various biomedical applications including photothermal therapy, targeted drug delivery, and molecular imaging. For in vivo applications, GNPs need to be prepared with very little or negligible cytotoxicitiy. Most GNPs are, however, prepared using growth-directing surfactants such as cetyl trimethylammonium bromide (CTAB), which are known to have considerable cytotoxicity. In this paper, we describe an approach to remove CTAB to a non-toxic concentration. We optimized the conditions for surface modification with methoxypolyethylene glycol thiol (mPEG), which replaced CTAB and formed a protective layer on the surface of gold nanorods (GNRs). The cytotoxicities of pristine and surface-modified GNRs were measured in primary human umbilical vein endothelial cells and human cell lines derived from hepatic carcinoma cells, embryonic kidney cells, and thyroid papillary carcinoma cells. Cytotoxicity assays revealed that treating cells with GNRs did not significantly affect cell viability except for thyroid papillary carcinoma cells. Thyroid cancer cells were more susceptible to residual CTAB, so CTAB had to be further removed by dialysis in order to use GNRs for thyroid cell targeting. PEGylated GNRs are further modified to present monoclonal antibodies that recognize a specific surface marker, Na-I symporter, for thyroid cells. Antibody-conjugated GNRs specifically targeted human thyroid cells in vitro.

  2. Osteoclasts but not osteoblasts are affected by a calcified surface treated with zoledronic acid in vitro

    SciTech Connect

    Schindeler, Aaron . E-mail: AaronS@chw.edu.au; Little, David G.

    2005-12-16

    Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption. Recent interest has centered on the effects of bisphosphonates on osteoblasts. Chronic dosing of osteoblasts with solubilized bisphosphonates has been reported to enhance osteogenesis and mineralization in vitro. However, this methodology poorly reflects the in vivo situation, where free bisphosphonate becomes rapidly bound to mineralized bone surfaces. To establish a more clinically relevant cell culture model, we cultured bone cells on calcium phosphate coated quartz discs pre-treated with the potent nitrogen-containing bisphosphonate, zoledronic acid (ZA). Binding studies utilizing [{sup 14}C]-labeled ZA confirmed that the bisphosphonate bound in a concentration-dependent manner over the 1-50 {mu}M dose range. When grown on ZA-treated discs, the viability of bone-marrow derived osteoclasts was greatly reduced, while the viability and mineralization of the osteoblastic MC3T3-E1 cell line were largely unaffected. This suggests that only bone resorbing cells are affected by bound bisphosphonate. However, this system does not account for transient exposure to unbound bisphosphonate in the hours following a clinical dosing. To model this event, we transiently treated osteoblasts with ZA in the absence of a calcified surface. Osteoblasts proved highly resistant to all transitory treatment regimes, even when utilizing ZA concentrations that prevented mineralization and/or induced cell death when dosed chronically. This study represents a pharmacologically more relevant approach to modeling bisphosphonate treatment on cultured bone cells and implies that bisphosphonate therapies may not directly affect osteoblasts at bone surfaces.

  3. Responses of fibroblasts and glial cells to nanostructured platinum surfaces

    NASA Astrophysics Data System (ADS)

    Pennisi, C. P.; Sevcencu, C.; Dolatshahi-Pirouz, A.; Foss, M.; Lundsgaard Hansen, J.; Nylandsted Larsen, A.; Zachar, V.; Besenbacher, F.; Yoshida, K.

    2009-09-01

    The chronic performance of implantable neural prostheses is affected by the growth of encapsulation tissue onto the stimulation electrodes. Encapsulation is associated with activation of connective tissue cells at the electrode's metallic contacts, usually made of platinum. Since surface nanotopography can modulate the cellular responses to materials, the aim of the present work was to evaluate the 'in vitro' responses of connective tissue cells to platinum strictly by modulating its surface nanoroughness. Using molecular beam epitaxy combined with sputtering, we produced platinum nanostructured substrates consisting of irregularly distributed nanopyramids and investigated their effect on the proliferation, cytoskeletal organization and cellular morphology of primary fibroblasts and transformed glial cells. Cells were cultured on these substrates and their responses to surface roughness were studied. After one day in culture, the fibroblasts were more elongated and their cytoskeleton less mature when cultured on rough substrates. This effect increased as the roughness of the surface increased and was associated with reduced cell proliferation throughout the observation period (4 days). Morphological changes also occurred in glial cells, but they were triggered by a different roughness scale and did not affect cellular proliferation. In conclusion, surface nanotopography modulates the responses of fibroblasts and glial cells to platinum, which may be an important factor in optimizing the tissue response to implanted neural electrodes.

  4. Analysis of cell surface antigens by Surface Plasmon Resonance imaging.

    PubMed

    Stojanović, Ivan; Schasfoort, Richard B M; Terstappen, Leon W M M

    2014-02-15

    Surface Plasmon Resonance (SPR) is most commonly used to measure bio-molecular interactions. SPR is used significantly less frequent for measuring whole cell interactions. Here we introduce a method to measure whole cells label free using the specific binding of cell surface antigens expressed on the surface of cancer cells and specific ligands deposited on sensor chips using an IBIS MX96 SPR imager (SPRi). As a model system, cells from the breast cancer cell line HS578T, SKBR3 and MCF7 were used. SPRi responses to Epithelial Cell Adhesion Molecule (EpCAM) antibody and other ligands coated on the sensor chips were measured. SPR curves show a response attributable to the sedimentation of the cells and a specific binding response on top of the initial response, the magnitude of which is dependent on the ligand density and the cell type used. Comparison of SPRi with flow cytometry showed similar EpCAM expression on MCF7, SKBR3 and HS578T cells.

  5. Adhesion of cells to polystyrene surfaces

    PubMed Central

    1983-01-01

    The surface treatment of polystyrene, which is required to make polystyrene suitable for cell adhesion and spreading, was investigated. Examination of surfaces treated with sulfuric acid or various oxidizing agents using (a) x-ray photoelectron and attenuated total reflection spectroscopy and (b) measurement of surface carboxyl-, hydroxyl-, and sulfur-containing groups by various radiochemical methods showed that sulfuric acid produces an insignificant number of sulfonic acid groups on polystyrene. This technique together with various oxidation techniques that render surfaces suitable for cell culture generated high surface densities of hydroxyl groups. The importance of surface hydroxyl groups for the adhesion of baby hamster kidney cells or leukocytes was demonstrated by the inhibition of adhesion when these groups were blocked: blocking of carboxyl groups did not inhibit adhesion and may raise the adhesion of a surface. These results applied to cell adhesion in the presence and absence of serum. The relative unimportance of fibronectin for the adhesion and spreading of baby hamster kidney cells to hydroxyl-rich surfaces was concluded when cells spread on such surfaces after protein synthesis was inhibited with cycloheximide, fibronectin was removed by trypsinization, and trypsin activity was stopped with leupeptin. PMID:6355120

  6. Cell-surface remodelling during mammalian erythropoiesis.

    PubMed

    Wraith, D C; Chesterton, C J

    1982-10-15

    Current evidence suggests that the major cell-surface modification occurring during mammalian erythropoiesis could be generated by two separate mechanisms: either selective loss of membrane proteins during enucleation or endocytosis at the subsequent reticulocyte and erythrocyte stages. The former idea was tested by collecting developing rabbit erythroid cells before and after the enucleation step and comparing their cell-surface protein composition via radiolabelling and electrophoresis. Few changes were observed. Our data thus lend support to the endocytosis mechanism.

  7. Profiling of the cell surface proteome.

    PubMed

    Jang, Jun Ho; Hanash, Samir

    2003-10-01

    The in depth-mining of the proteome necessitates the comprehensive analysis of proteins in individual subcellular compartments to uncover interesting patterns of protein expression that include assessment of protein location, trafficking and of post-translational modifications that are location specific. One of the compartments of substantial interest from a diagnostic and therapeutic point of view is the plasma membrane which contains intrinsic membrane proteins and other proteins expressed on the cell surface. Technologies are currently available for the comprehensive profiling of the cell surface proteome that rely on protein tagging of intact cells. Studies are emerging that point to unexpected patterns of expression of specific proteins on the cell surface, with a common occurrence of proteins previously considered to occur predominantly in other compartments, notably the endoplasmic reticulum. The profiling of the cell surface and plasma membrane proteomes will likely provide novel insights and uncover disease related alterations. PMID:14625857

  8. Metformin selectively affects human glioblastoma tumor-initiating cell viability

    PubMed Central

    Würth, Roberto; Pattarozzi, Alessandra; Gatti, Monica; Bajetto, Adirana; Corsaro, Alessandro; Parodi, Alessia; Sirito, Rodolfo; Massollo, Michela; Marini, Cecilia; Zona, Gianluigi; Fenoglio, Daniela; Sambuceti, Gianmario; Filaci, Gilberto; Daga, Antonio; Barbieri, Federica; Florio, Tullio

    2013-01-01

    Cancer stem cell theory postulates that a small population of tumor-initiating cells is responsible for the development, progression and recurrence of several malignancies, including glioblastoma. In this perspective, tumor-initiating cells represent the most relevant target to obtain effective cancer treatment. Metformin, a first-line drug for type II diabetes, was reported to possess anticancer properties affecting the survival of cancer stem cells in breast cancer models. We report that metformin treatment reduced the proliferation rate of tumor-initiating cell-enriched cultures isolated from four human glioblastomas. Metformin also impairs tumor-initiating cell spherogenesis, indicating a direct effect on self-renewal mechanisms. Interestingly, analyzing by FACS the antiproliferative effects of metformin on CD133-expressing subpopulation, a component of glioblastoma cancer stem cells, a higher reduction of proliferation was observed as compared with CD133-negative cells, suggesting a certain degree of cancer stem cell selectivity in its effects. In fact, glioblastoma cell differentiation strongly reduced sensitivity to metformin treatment. Metformin effects in tumor-initiating cell-enriched cultures were associated with a powerful inhibition of Akt-dependent cell survival pathway, while this pathway was not affected in differentiated cells. The specificity of metformin antiproliferative effects toward glioblastoma tumor-initiating cells was confirmed by the lack of significant inhibition of normal human stem cells (umbilical cord-derived mesenchymal stem cells) in vitro proliferation after metformin exposure. Altogether, these data clearly suggest that metformin exerts antiproliferative activity on glioblastoma cells, showing a higher specificity toward tumor-initiating cells, and that the inhibition of Akt pathway may represent a possible intracellular target of this effect. PMID:23255107

  9. High vacuum cells for classical surface techniques

    SciTech Connect

    Martinez, Imee Su; Baldelli, Steven

    2010-04-15

    Novel glass cells were designed and built to be able to perform surface potential and surface tension measurements in a contained environment. The cells can withstand pressures of approximately 1x10{sup -6} Torr, providing a reasonable level of control in terms of the amounts of volatile contaminants during experimentation. The measurements can take several hours; thus the cells help maintain the integrity of the sample in the course of the experiment. To test for the feasibility of the cell design, calibration measurements were performed. For the surface potential cell, the modified TREK 6000B-7C probe exhibited performance comparable to its unmodified counterpart. The correlation measurements between applied potential on the test surface and the measured potential showed R-values very close to 1 as well as standard deviation values of less than 1. Results also demonstrate improved measurement values for experiments performed in vacuum. The surface tension cell, on the other hand, which was used to perform the pendant drop method, was tested on common liquids and showed percentage errors of 0.5% when compared to literature values. The fabricated cells redefine measurements using classical surface techniques, providing unique and novel methods of sample preparation, premeasurement preparation, and sample analysis at highly beneficial expenditure cost.

  10. Quantum Efficiency Loss after PID Stress: Wavelength Dependence on Cell Surface and Cell Edge

    SciTech Connect

    Oh, Jaewon; Bowden, Stuart; TamizhMani, GovindaSamy; Hacke, Peter

    2015-06-14

    It is known that the potential induced degradation (PID) stress of conventional p-base solar cells affects power, shunt resistance, junction recombination, and quantum efficiency (QE). One of the primary solutions to address the PID issue is a modification of chemical and physical properties of antireflection coating (ARC) on the cell surface. Depending on the edge isolation method used during cell processing, the ARC layer near the edges may be uniformly or non-uniformly damaged. Therefore, the pathway for sodium migration from glass to the cell junction could be either through all of the ARC surface if surface and edge ARC have low quality or through the cell edge if surface ARC has high quality but edge ARC is defective due to certain edge isolation process. In this study, two PID susceptible cells from two different manufacturers have been investigated. The QE measurements of these cells before and after PID stress were performed at both surface and edge. We observed the wavelength dependent QE loss only in the first manufacturer's cell but not in the second manufacturer's cell. The first manufacturer's cell appeared to have low quality ARC whereas the second manufacturer's cell appeared to have high quality ARC with defective edge. To rapidly screen a large number of cells for PID stress testing, a new but simple test setup that does not require laminated cell coupon has been developed and is used in this investigation.

  11. Low-Reflectance Surfaces For Solar Cells

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Landis, Geoffrey A.; Fatemi, Navid; Jenkins, Phillip P.

    1994-01-01

    Improved method for increasing solar cell efficiency has potential application for space-based and terrestrial solar power systems and optoelectronic devices. Etched low-angle grooves help recover reflected light. Light reflected from v-grooved surface trapped in cover glass and adhesive by total internal reflection. Reflected light redirected onto surface, and greater fraction of incident light absorbed, producing more electrical energy in InP solar photovoltaic cell.

  12. Enzyme Evolution by Yeast Cell Surface Engineering.

    PubMed

    Miura, Natsuko; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2015-01-01

    Artificial evolution of proteins with the aim of acquiring novel or improved functionality is important for practical applications of the proteins. We have developed yeast cell surface engineering methods (or arming technology) for evolving enzymes. Here, we have described yeast cell surface engineering coupled with in vivo homologous recombination and library screening as a method for the artificial evolution of enzymes such as firefly luciferases. Using this method, novel luciferases with improved substrate specificity and substrate reactivity were engineered. PMID:26060078

  13. Plant surface wax affects parasitoid's response to host footprints

    NASA Astrophysics Data System (ADS)

    Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

    2008-10-01

    The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.

  14. Factors Affecting Peptide Interactions with Surface-Bound Microgels.

    PubMed

    Nyström, Lina; Nordström, Randi; Bramhill, Jane; Saunders, Brian R; Álvarez-Asencio, Rubén; Rutland, Mark W; Malmsten, Martin

    2016-02-01

    Effects of electrostatics and peptide size on peptide interactions with surface-bound microgels were investigated with ellipsometry, confocal microscopy, and atomic force microscopy (AFM). Results show that binding of cationic poly-L-lysine (pLys) to anionic, covalently immobilized, poly(ethyl acrylate-co-methacrylic acid) microgels increased with increasing peptide net charge and microgel charge density. Furthermore, peptide release was facilitated by decreasing either microgel or peptide charge density. Analogously, increasing ionic strength facilitated peptide release for short peptides. As a result of peptide binding, the surface-bound microgels displayed pronounced deswelling and increased mechanical rigidity, the latter quantified by quantitative nanomechanical mapping. While short pLys was found to penetrate the entire microgel network and to result in almost complete charge neutralization, larger peptides were partially excluded from the microgel network, forming an outer peptide layer on the microgels. As a result of this difference, microgel flattening was more influenced by the lower Mw peptide than the higher. Peptide-induced deswelling was found to be lower for higher Mw pLys, the latter effect not observed for the corresponding microgels in the dispersed state. While the effects of electrostatics on peptide loading and release were similar to those observed for dispersed microgels, there were thus considerable effects of the underlying surface on peptide-induced microgel deswelling, which need to be considered in the design of surface-bound microgels as carriers of peptide loads, for example, in drug delivery or in functionalized biomaterials. PMID:26750986

  15. Reactivation of cell surface transport in Reticulomyxa.

    PubMed

    Orokos, D D; Bowser, S S; Travis, J L

    1997-01-01

    Granuloreticulosean protists transport particles (e.g., bacteria, algae, and sand grains) along the outer surfaces of their pseudopodia. This cell surface transport plays a vital role in feeding, reproduction, shell construction, and locomotion and can be visualized by the movements of extracellularly adherent polystyrene microspheres (i.e., latex beads). Our videomicroscopic analyses of transport associated with the pseudopodia of Reticulomyxa filosa revealed two distinct types of both intracellular and cell surface transport: (1) saltatory, bidirectional transport of individual or clustered organelles and/or surface-attached particles, and (2) continuous, unidirectional bulk or "resolute" motion of aggregated organelles and/or surface-bound particles. Organelles and surface-attached polystyrene microspheres remained firmly attached to the microtubule cytoskeletons of detergent-extracted pseudopodia. Both saltatory and resolute organelle and surface transport reactivated upon the addition of 0.01-1.0 mM ATP. At 1 mM ATP, the velocities of reactivated saltatory transport were indistinguishable from those observed in vivo. The reactivated transport was microtubule-dependent and was not inhibited by incubation with Ca(2+)-gelsolin under conditions that abolish rhodamine-phalloidin detection of actin filaments. These findings provide further support that both intracellular organelle and membrane surface transport are mediated by a common mechanism, and establish Reticulomyxa as a unique model system to further study the mechanochemistry of cell surface transport in vitro.

  16. Structure and functions of fungal cell surfaces

    NASA Technical Reports Server (NTRS)

    Nozawa, Y.

    1984-01-01

    A review with 24 references on the biochemistry, molecular structure, and function of cell surfaces of fungi, especially dermatophytes: the chemistry and structure of the cell wall, the effect of polyene antibiotics on the morphology and function of cytoplasmic membranes, and the chemical structure and function of pigments produced by various fungi are discussed.

  17. Probes for anionic cell surface detection

    DOEpatents

    Smith, Bradley D.

    2013-03-05

    Embodiments of the present invention are generally directed to compositions comprising a class of molecular probes for detecting the presence of anionic cell surfaces. Embodiments include compositions that are enriched for these compositions and preparations, particularly preparations suitable for use as laboratory/clinical reagents and diagnostic indicators, either alone or as part of a kit. An embodiment of the invention provides for a highly selective agent useful in the discernment and identification of dead or dying cells, such as apoptotic cells, in a relatively calcium-free environment. An embodiment of the invention provides a selective agent for the identification of bacteria in a mixed population of bacterial cells and nonbacterial cells.

  18. Multi-scale cell/surface interaction on modified titanium aluminum vanadium surfaces

    NASA Astrophysics Data System (ADS)

    Chen, Jianbo

    This dissertation presents a series of experimental studies of the effects of multi-scale cell/surface interactions on modified Ti-6Al-4V surfaces. These include laser-grooved surfaces; porous structures and RGD-coated laser-grooved surfaces. A nano-second DPSS UV lasers with a Gaussian pulse energy profile was used to introduce the desired micro-groove geometries onto Ti-6Al-4V surfaces. This was done without inducing micro-cracks or significant changes in surface chemistry within the heat affected zones. The desired 8-12 mum groove depths and widths were achieved by the control of pulse frequency, scan speed, and the lens focal length that controls spot size. The interactions between human osteosarcoma (HOS) cells and laser-grooved Ti-6Al-4V surfaces were investigated after 48 hours of cell culture. The cell behavior, including cell spreading, alignment and adhesion, was elucidated using scanning electronic microscopy (SEM), immuno-fluorescence staining and enzymatic detachment. Contact guidance was shown to increase as grooved spacing decreased. For the range of micro-groove geometries studied, micro-grooves with groove spacings of 20 mum provided the best combination of cell orientation and adhesion. Short-term adhesion experiments (15 mins to 1 day) also revealed that there is a positive correlation between cell orientation and cell adhesion. Contact guidance on the micro-grooved surfaces is shown to be enhanced by nano- and micro-scale asperities that provide sites for the attachment of lamellopodia during cell locomotion and spreading. Contact guidance is also promoted by the geometrical confinement provided by laser grooves. An experimental study of initial cell spreading and ingrowth into Ti-6Al-4V porous structures was also carried out on porous structures with different pore sizes and geometries. A combination of SEM, the tetrazolium salt (MTT) colorimetric assay and enzymatic detachment were used to study cell spreading and adhesion. The extent of cell

  19. Estrogen deficiency heterogeneously affects tissue specific stem cells in mice.

    PubMed

    Kitajima, Yuriko; Doi, Hanako; Ono, Yusuke; Urata, Yoshishige; Goto, Shinji; Kitajima, Michio; Miura, Kiyonori; Li, Tao-Sheng; Masuzaki, Hideaki

    2015-01-01

    Postmenopausal disorders are frequently observed in various organs, but their relationship with estrogen deficiency and mechanisms remain unclear. As tissue-specific stem cells have been found to express estrogen receptors, we examined the hypothesis that estrogen deficiency impairs stem cells, which consequently contributes to postmenopausal disorders. Six-week-old C57BL/6 female mice were ovariectomized, following which they received 17β-estradiol replacement or vehicle (control). Sham-operated mice were used as healthy controls. All mice were killed for evaluation 2 months after treatments. Compared with the healthy control, ovariectomy significantly decreased uterine weight, which was partially recovered by 17β-estradiol replacement. Ovariectomy significantly increased the numbers of c-kit-positive hematopoietic stem/progenitor cells in bone marrow, but impaired their capacity to grow mixed cell-type colonies in vitro. Estrogen replacement further increased the numbers of c-kit-positive hematopoietic stem/progenitor cells in bone marrow, without significantly affecting colony growth in vitro. The number of CD105-positive mesenchymal stem cells in bone marrow also significantly decreased after ovariectomy, but completely recovered following estrogen replacement. Otherwise, neither ovariectomy nor estrogen replacement changed the number of Pax7-positive satellite cells, which are a skeletal muscle-type stem cell. Estrogen deficiency heterogeneously affected tissue-specific stem cells, suggesting a likely and direct relationship with postmenopausal disorders. PMID:26245252

  20. Cell Adhesion on Surface-Functionalized Magnesium.

    PubMed

    Wagener, Victoria; Schilling, Achim; Mainka, Astrid; Hennig, Diana; Gerum, Richard; Kelch, Marie-Luise; Keim, Simon; Fabry, Ben; Virtanen, Sannakaisa

    2016-05-18

    The biocompatibility of commercially pure magnesium-based (cp Mg) biodegradable implants is compromised of strong hydrogen evolution and surface alkalization due to high initial corrosion rates of cp Mg in the physiological environment. To mitigate this problem, the addition of corrosion-retarding alloying elements or coating of implant surfaces has been suggested. In the following work, we explored the effect of organic coatings on long-term cell growth. cp Mg was coated with aminopropyltriehtoxysilane + vitamin C (AV), carbonyldiimidazole (CDI), or stearic acid (SA). All three coatings have been previously suggested to reduce initial corrosion and to enhance protein adsorption and hence cell adhesion on magnesium surfaces. Endothelial cells (DH1+/+) and osteosarcoma cells (MG63) were cultured on coated samples for up to 20 days. To quantify Mg corrosion, electrochemical impedance spectroscopy (EIS) was measured after 1, 3, and 5 days of cell culture. We also investigated the speed of initial cell spreading after seeding using fluorescently labeled fibroblasts (NIH/3T3). Hydrogen evolution after contact with cell culture medium was markedly decreased on AV- and SA-coated Mg compared to uncoated Mg. These coatings also showed improved cell adhesion and spreading after 24 h of culture comparable to tissue-treated plastic surfaces. On AV-coated cp Mg, a confluent layer of endothelial cells formed after 5 days and remained intact for up to 20 days. Together, these data demonstrate that surface coating with AV is a viable strategy for improving long-term biocompatibility of cp Mg-based implants. EIS measurements confirmed that the presence of a confluent cell layer increased the corrosion resistance. PMID:27089250

  1. Free-surface stability criterion as affected by velocity distribution

    USGS Publications Warehouse

    Cheng-Lung, Chen

    1995-01-01

    This paper examines how the velocity distribution of flow in open channels affects the kinematic and dynamic wave velocities, from which the various forms of the Vedernikov number V can be formulated. When V >1, disturbances created in open-channel flow will amplify in the form of roll waves; when V <1, some (though not all) disturbances will attenuate. A study of the Vedernikov stability criterion reveals that it can be readily deduced within the framework of the kinematic and dynamic wave theories by comparing the kinematic wave velocity to the corresponding dynamic wave velocity. -from Author

  2. Effect of hydroxyapatite surface morphology on cell adhesion.

    PubMed

    Iwamoto, Takashi; Hieda, Yohki; Kogai, Yasumichi

    2016-12-01

    We obtained hydroxyapatite (HAp) materials as a block by mixing HAp nanoparticles and polymer, and then calcining the mixtures. The surface morphology of the HAp materials was tuned by varying heat treatment conditions. After calcining the mixtures at 1200 or 800°C for 4h, the surface morphology of the HAp materials was flat or convexo-concave, respectively. The flat surface morphology, which showed micrometer-ordered grain boundaries, was formed by the aggregation of HAp nanoparticles. On the other hand, the convexo-concave surface morphology resulted from the agglomeration of HAp nanoparticles after heat treatment at 800°C for 4h with nanometer-ordered particle size. We tested cell adhesion to HAp materials with flat or convexo-concave surface morphology and found that cells adhered well to the flat HAp materials but not to the convexo-concave HAp materials. This technique for selectively preparing HAp materials with flat or convexo-concave surface morphology was very easy because we merely mixed commercial HAp nanoparticles with polymer and then calcined the mixtures. As a result, the heat treatment temperature affected the surface morphology of our HAp materials, and their surface morphologies contributed to cell adhesion independently of other material properties. PMID:27612825

  3. Effect of hydroxyapatite surface morphology on cell adhesion.

    PubMed

    Iwamoto, Takashi; Hieda, Yohki; Kogai, Yasumichi

    2016-12-01

    We obtained hydroxyapatite (HAp) materials as a block by mixing HAp nanoparticles and polymer, and then calcining the mixtures. The surface morphology of the HAp materials was tuned by varying heat treatment conditions. After calcining the mixtures at 1200 or 800°C for 4h, the surface morphology of the HAp materials was flat or convexo-concave, respectively. The flat surface morphology, which showed micrometer-ordered grain boundaries, was formed by the aggregation of HAp nanoparticles. On the other hand, the convexo-concave surface morphology resulted from the agglomeration of HAp nanoparticles after heat treatment at 800°C for 4h with nanometer-ordered particle size. We tested cell adhesion to HAp materials with flat or convexo-concave surface morphology and found that cells adhered well to the flat HAp materials but not to the convexo-concave HAp materials. This technique for selectively preparing HAp materials with flat or convexo-concave surface morphology was very easy because we merely mixed commercial HAp nanoparticles with polymer and then calcined the mixtures. As a result, the heat treatment temperature affected the surface morphology of our HAp materials, and their surface morphologies contributed to cell adhesion independently of other material properties.

  4. ABSENCE OF SCLEROSTIN ADVERSELY AFFECTS B CELL SURVIVAL

    PubMed Central

    Cain, Corey J.; Rueda, Randell; McLelland, Bryce; Collette, Nicole M.; Loots, Gabriela G.; Manilay, Jennifer O.

    2012-01-01

    Increased osteoblast activity in sclerostin-knockout (Sost−/−) mice results in generalized hyperostosis and bones with small bone marrow cavities due to hyperactive mineralizing osteoblast populations. Hematopoietic cell fate decisions are dependent on their local microenvironment, which contains osteoblast and stromal cell populations that support both hematopoietic stem cell quiescence and facilitate B cell development. In this study, we investigated whether high bone mass environments affect B cell development via the utilization of Sost−/− mice, a model of sclerosteosis. We found the bone marrow of Sost−/− mice to be specifically depleted of B cells, due to elevated apoptosis at all B cell developmental stages. In contrast, B cell function in the spleen was normal. Sost expression analysis confirmed that Sost is primarily expressed in osteocytes and is not expressed in any hematopoietic lineage, which indicated that the B cell defects in Sost−/− mice are non-cell autonomous and this was confirmed by transplantation of wildtype (WT) bone marrow into lethally irradiated Sost−/− recipients. WT→Sost−/− chimeras displayed a reduction in B cells, whereas reciprocal Sost−/−→WT chimeras did not, supporting the idea that the Sost−/− bone environment cannot fully support normal B cell development. Expression of the pre-B cell growth stimulating factor, Cxcl12, was significantly lower in bone marrow stromal cells of Sost−/− mice while the Wnt target genes Lef-1 and Ccnd1 remained unchanged in B cells. Taken together, these results demonstrate a novel role for Sost in the regulation of bone marrow environments that support B cells. PMID:22434688

  5. How strain affects the reactivity of surface metal oxide catalysts.

    PubMed

    Amakawa, Kazuhiko; Sun, Lili; Guo, Chunsheng; Hävecker, Michael; Kube, Pierre; Wachs, Israel E; Lwin, Soe; Frenkel, Anatoly I; Patlolla, Anitha; Hermann, Klaus; Schlögl, Robert; Trunschke, Annette

    2013-12-16

    Highly dispersed molybdenum oxide supported on mesoporous silica SBA-15 has been prepared by anion exchange resulting in a series of catalysts with changing Mo densities (0.2-2.5 Mo atoms nm(-2) ). X-ray absorption, UV/Vis, Raman, and IR spectroscopy indicate that doubly anchored tetrahedral dioxo MoO4 units are the major surface species at all loadings. Higher reducibility at loadings close to the monolayer measured by temperature-programmed reduction and a steep increase in the catalytic activity observed in metathesis of propene and oxidative dehydrogenation of propane at 8 % of Mo loading are attributed to frustration of Mo oxide surface species and lateral interactions. Based on DFT calculations, NEXAFS spectra at the O-K-edge at high Mo loadings are explained by distorted MoO4 complexes. Limited availability of anchor silanol groups at high loadings forces the MoO4 groups to form more strained configurations. The occurrence of strain is linked to the increase in reactivity. PMID:24259425

  6. Progenitor cells for ocular surface regenerative therapy.

    PubMed

    Casaroli-Marano, Ricardo P; Nieto-Nicolau, Nuria; Martínez-Conesa, Eva M

    2013-01-01

    The integrity and normal function of the corneal epithelium are essential for maintaining the cornea's transparency and vision. The existence of a cell population with progenitor characteristics in the limbus maintains a dynamic of constant epithelial repair and renewal. Currently, cell-based therapies for bio-replacement, such as cultured limbal epithelial transplantation and cultured oral mucosal epithelial transplantation, present very encouraging clinical results for treating limbal stem cell deficiencies. Another emerging therapeutic strategy consists of obtaining and implementing human progenitor cells of different origins using tissue engineering methods. The development of cell-based therapies using stem cells, such as human adult mesenchymal stromal cells, represents a significant breakthrough in the treatment of certain eye diseases and also offers a more rational, less invasive and more physiological approach to ocular surface regeneration. PMID:23257987

  7. Progenitor cells for ocular surface regenerative therapy.

    PubMed

    Casaroli-Marano, Ricardo P; Nieto-Nicolau, Nuria; Martínez-Conesa, Eva M

    2013-01-01

    The integrity and normal function of the corneal epithelium are essential for maintaining the cornea's transparency and vision. The existence of a cell population with progenitor characteristics in the limbus maintains a dynamic of constant epithelial repair and renewal. Currently, cell-based therapies for bio-replacement, such as cultured limbal epithelial transplantation and cultured oral mucosal epithelial transplantation, present very encouraging clinical results for treating limbal stem cell deficiencies. Another emerging therapeutic strategy consists of obtaining and implementing human progenitor cells of different origins using tissue engineering methods. The development of cell-based therapies using stem cells, such as human adult mesenchymal stromal cells, represents a significant breakthrough in the treatment of certain eye diseases and also offers a more rational, less invasive and more physiological approach to ocular surface regeneration.

  8. Resolution of contamination problems affecting laser surface certification inspection

    NASA Astrophysics Data System (ADS)

    Jackson, L. C.

    1982-03-01

    Contamination from particulate and organic residues which interfered, with the laser surface certification (LSC) inspection of some parts was found to come from three sources: particulate and organic residues from polishing compounds; organic films from cleaning solvents; and particles and organic residues transferred from plastic fixtures used to process these parts. The manufacturing cleaning process was not effective in removing all polishing compound residues, and an extensive cleaning procedure was developed using two solvents in a multicycle ultrasonic/vapor degreasing procedure. Parts were then subjected to gas plasma cleaning which removed the organic films left by the solvent cleaning. Plastic and rubber materials were evaluated for their contamination transfer characteristics; a fluorocarbon elastomer was the least contaminating. Inspection data established the efficacy of the cleaning procedure. After design relaxation, a single stage ultrasonic vapor degreasing process was used to achieve product acceptance.

  9. Quantitative evolution of volcanic surfaces affected by erosional processes

    NASA Astrophysics Data System (ADS)

    Lahitte, Pierre; Boillot-Airaksinen, Kim; Germa, Aurélie; Lavigne, Franck

    2016-04-01

    Variations through time of erosion dynamics, a key point to investigate correlation between climates and landform evolution, still remains poorly documented. One of the main issue in this type of study is the difficulty in determining for how long the erosion has operated. For this purpose, volcanic contexts are particularly suitable for defining the temporal dynamics governing erosion since the age of volcanic activity also constrains the age of emplacement of the surface today eroded, and thus the erosion duration. Furthermore, quantitative analysis of river profiles offers the opportunity to discriminate, among the wide variety of geological phenomena influencing erosion, their respective influence. Quantification of erosion processes and constrain of their signature on reliefs can be addressed by a morphometric approach of river profiles in volcanic environment through the analysis of digital topography (DEM). Break in slope zones, the so-called knickpoints, are usually related to a retreat of the point between the relict channel, upstream, and the adjusted channel, downstream. They are induced by either a lithological contrast, a change in the base level, uplift or eustatism, or a rejuvenation of the age of the volcanic surface. The stream long-profile and its watershed is also investigated by their concavity and hypsometric indexes to determine for how long the complexity and its heterogeneity along the valley incision remain visible. The present study focusses on the erosion of volcanoes in the Lesser Antilles, Reunion Island and Lombok Island (Indonesia). All located in tropical environments, these volcanoes offer a wide diversity of age (30 - 0 Ma) and lithology for investigating the respective influence of geological processes that have induced a large variety of shapes and volcanic history that we try to correlate to geometry of river profiles.

  10. Surface cell immobilization within perfluoroalkoxy microchannels

    NASA Astrophysics Data System (ADS)

    Stojkovič, Gorazd; Krivec, Matic; Vesel, Alenka; Marinšek, Marjan; Žnidaršič-Plazl, Polona

    2014-11-01

    Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor® and Topas®.

  11. Micropatterned Azopolymer Surfaces Modulate Cell Mechanics and Cytoskeleton Structure.

    PubMed

    Rianna, Carmela; Ventre, Maurizio; Cavalli, Silvia; Radmacher, Manfred; Netti, Paolo A

    2015-09-30

    Physical and chemical characteristics of materials are important regulators of cell behavior. In particular, cell elasticity is a fundamental parameter that reflects the state of a cell. Surface topography finely modulates cell fate and function via adhesion mediated signaling and cytoskeleton generated forces. However, how topographies alter cell mechanics is still unclear. In this work we have analyzed the mechanical properties of peripheral and nuclear regions of NIH-3T3 cells on azopolymer substrates with different topographic patterns. Micrometer scale patterns in the form of parallel ridges or square lattices of surface elevations were encoded on light responsive azopolymer films by means of contactless optical methods. Cell mechanics was investigated by atomic force microscopy (AFM). Cells and consequently the cell cytoskeleton were oriented along the linear patterns affecting cytoskeletal structures, e.g., formation of actin stress fibers. Our data demonstrate that topographic substrate patterns are recognized by cells and mechanical information is transferred by the cytoskeleton. Furthermore, cytoskeleton generated forces deform the nucleus, changing its morphology that appears to be related to different mechanical properties in the nuclear region.

  12. The Cell Surface Proteome of Human Mesenchymal Stromal Cells

    PubMed Central

    Pursche, Theresia; Bornhäuser, Martin; Corbeil, Denis; Hoflack, Bernard

    2011-01-01

    Background Multipotent human mesenchymal stromal cells (hMSCs) are considered as promising biological tools for regenerative medicine. Their antibody-based isolation relies on the identification of reliable cell surface markers. Methodology/Principal Findings To obtain a comprehensive view of the cell surface proteome of bone marrow-derived hMSCs, we have developed an analytical pipeline relying on cell surface biotinylation of intact cells using cell impermeable, cleavable sulfo-NHS-SS-biotin to enrich the plasma membrane proteins and mass spectrometry for identification with extremely high confidence. Among the 888 proteins identified, we found ≈200 bona fide plasma membrane proteins including 33 cell adhesion molecules and 26 signaling receptors. In total 41 CD markers including 5 novel ones (CD97, CD112, CD239, CD276, and CD316) were identified. The CD markers are distributed homogenously within plastic-adherent hMSC populations and their expression is modulated during the process of adipogenesis or osteogenesis. Moreover, our in silico analysis revealed a significant difference between the cell surface proteome of hMSCs and that of human embryonic stem cells reported previously. Conclusions/Significance Collectively, our analytical methods not only provide a basis for further studies of mechanisms maintaining the multipotency of hMSCs within their niches and triggering their differentiation after signaling, but also a toolbox for a refined antibody-based identification of hMSC populations from different tissues and their isolation for therapeutic intervention. PMID:21637820

  13. Factors affecting survival of bacteriophage on tomato leaf surfaces.

    PubMed

    Iriarte, F B; Balogh, B; Momol, M T; Smith, L M; Wilson, M; Jones, J B

    2007-03-01

    The ability of bacteriophage to persist in the phyllosphere for extended periods is limited by many factors, including sunlight irradiation, especially in the UV zone, temperature, desiccation, and exposure to copper bactericides. The effects of these factors on persistence of phage and formulated phage (phage mixed with skim milk) were evaluated. In field studies, copper caused significant phage reduction if applied on the day of phage application but not if applied 4 or 7 days in advance. Sunlight UV was evaluated for detrimental effects on phage survival on tomato foliage in the field. Phage was applied in the early morning, midmorning, early afternoon, and late evening, while UVA plus UVB irradiation and phage populations were monitored. The intensity of UV irradiation positively correlated with phage population decline. The protective formulation reduced the UV effect. In order to demonstrate direct effects of UV, phage suspensions were exposed to UV irradiation and assayed for effectiveness against bacterial spot of tomato. UV significantly reduced phage ability to control bacterial spot. Ambient temperature had a pronounced effect on nonformulated phage but not on formulated phages. The effects of desiccation and fluorescent light illumination on phage were investigated. Desiccation caused a significant but only slight reduction in phage populations after 60 days, whereas fluorescent light eliminated phages within 2 weeks. The protective formulation eliminated the reduction caused by both of these factors. Phage persistence was dramatically affected by UV, while the other factors had less pronounced effects. Formulated phage reduced deleterious effects of the studied environmental factors. PMID:17259361

  14. Effects of surface viscoelasticity on cellular responses of endothelial cells

    PubMed Central

    Hosseini, Motahare-Sadat; Katbab, Ali Asghar

    2014-01-01

    Background: One area of nanoscience deals with nanoscopic interactions between nanostructured materials and biological systems. To elucidate the effects of the substrate surface morphology and viscoelasticity on cell proliferation, fractal analysis was performed on endothelial cells cultured on nanocomposite samples based on silicone rubber (SR) and various concentrations of organomodified nanoclay (OC). Methods: The nanoclay/SR ratio was tailored to enhance cell behavior via changes in sample substrate surface roughness and viscoelasticity. Results: Surface roughness of the cured SR filled with negatively-charged nanosilicate layers had a greater effect than elasticity on cell growth. The surface roughness of SR nanocomposite samples increased with increasing the OC content, leading to enhanced cell growth and extracellular matrix (ECM) remodeling. This was consistent with the decrease in SR segmental motions and damping factor as the primary viscoelastic parameters by the nanosilicate layers with increasing clay concentrations. Conclusions: The inclusion of clay nanolayers affected the growth and behavior of endothelial cells on microtextured SR. PMID:26989733

  15. Mendelian and non-mendelian mutations affecting surface antigen expression in Paramecium tetraurelia

    SciTech Connect

    Epstein, L.M.; Forney, J.D.

    1984-08-01

    A screening procedure was devised for the isolation of X-ray-induced mutations affecting the expression of the A immobilization antigen (i-antigen) in Paramecium tetraurelia. Two of the mutations isolated by this procedure proved to be in modifier genes. The two genes are unlinked to each other and unlinked to the structural A i-antigen gene. These are the first modifier genes identified in a Paramecium sp. that affect surface antigen expression. Another mutation was found to be a deletion of sequences just downstream from the A i-antigen gene. In cells carrying this mutation, the A i-antigen gene lies in close proximity to the end of a macronuclear chromosome. The expression of the A i-antigen is not affected in these cells, demonstrating that downstream sequences are not important for the regulation and expression of the A i-antigen gene. A stable cell line was also recovered which shows non-Mendelian inheritance of a macronuclear deletion of the A i-antigen gene. This mutant does not contain the gene in its macronucleus, but contains a complete copy of the gene in its micronucleus. In the cytoplasm of wild-type animals, the micronuclear gene is included in the developing macronucleus; in the cytoplasm of the mutant, the incorporation of the A i-antigen gene into the macronucleus is inhibited. This is the first evidence that a mechanism is available in ciliates to control the expression of a gene by regulating its incorporation into developing macronuclei.

  16. Vesicle trafficking and cell surface membrane patchiness.

    PubMed

    Tang, Q; Edidin, M

    2001-07-01

    Membrane proteins and lipids often appear to be distributed in patches on the cell surface. These patches are often assumed to be membrane domains, arising from specific molecular associations. However, a computer simulation (Gheber and Edidin, 1999) shows that membrane patchiness may result from a combination of vesicle trafficking and dynamic barriers to lateral mobility. The simulation predicts that the steady-state patches of proteins and lipids seen on the cell surface will decay if vesicle trafficking is inhibited. To test this prediction, we compared the apparent sizes and intensities of patches of class I HLA molecules, integral membrane proteins, before and after inhibiting endocytic vesicle traffic from the cell surface, either by incubation in hypertonic medium or by expression of a dominant-negative mutant dynamin. As predicted by the simulation, the apparent sizes of HLA patches increased, whereas their intensities decreased after endocytosis and vesicle trafficking were inhibited. PMID:11423406

  17. Resolution of contamination problems affecting Laser-Surface-Certification inspection

    SciTech Connect

    Jackson, L.C.

    1982-03-01

    Contamination from particulate and organic residues has interfered with the Laser Surface Certification (LSC) inspection of some parts, subsequently preventing their certification to the Ernest Orlando Lawrence Livermore National Laboratory (LLNL) product specification. Contamination was found to come from three sources: particulate and organic residues from polishing compounds; organic films from cleaning solvents; and particles and organic residues transferred from plastic fixtures used to process these parts. The manufacturing cleaning process was not effective in removing all polishing compound residues, and an extensive cleaning procedure was developed using two solvents in a multicycle ultrasonic/vapor degreasing procedure. Parts were then subjected to gas plasma cleaning which removed the organic films left by the solvent cleaning. Plastic and rubber materials were evaluated for their contamination transfer characteristics; a fluorocarbon elastomer was the least contaminating. Inspection data established the efficacy of the cleaning procedure. After design relaxation, Bendix Kansas City was able to rely on a single-stage ultrasonic vapor degreasing process to achieve product acceptance.

  18. Surface texturing and patterning in solar cells

    SciTech Connect

    Green, M.A.

    1993-11-01

    Surface texture can perform a number of functions in modern solar cell design. The most obvious function is in control of reflection from surfaces on which sunlight is incident. However, texture can also be used to influence the fate of light that is refracted into the cell. Light steering by surface texture can ensure this refracted light is absorbed in regions of the cell which are most responsive. When used with rear reflectors, surface texture can help trap weakly absorbed light into the cell, increasing the effective path length or optical thickness of the cell by factors of 30--60. Two general types of texture are considered. One involves macroscopic features of controlled shape designed to control the direction of interacting light. The other is based on the use of irregular features of size comparable to wavelength of the light. These can be very effective in scattering light into a wide range of directions. Non-optical uses of texture are also briefly described. 62 refs., 22 figs.

  19. Surface cell density effects on Escherichia coli gene expression during cell attachment.

    PubMed

    Mauter, Meagan S; Mauter, Meagan; Fait, Aaron; Elimelech, Menachem; Herzberg, Moshe

    2013-06-18

    Escherichia coli attachment to a surface initiates a complex series of interconnected signaling and regulation pathways that promote biofilm formation and maturation. The present work investigates the effect of deposited cell density on E. coli cell physiology, metabolic activity, and gene expression in the initial stages of biofilm development. Deposited cell density is controlled by exploiting the relationship between ionic strength and bacterial attachment efficiency in a packed bed column. Distinct differences in cell transcriptome are analyzed by comparing sessile cultures at two different cell surface densities and differentiating ionic strength effects by analyzing planktonic cultures in parallel. Our results indicate that operons regulating trypotophan production and the galactitol phosphotransferase system (including dihydroxyacetone phosphate synthesis) are strongly affected by cell density on the surface. Additional transcriptome and metabolomic impacts of cell density on succinate, proline, and pyroglutamic acid systems are also reported. These results are consistent with the hypothesis that surface cell density plays a major role in sessile cell physiology, commencing with the first stage of biofilm formation. These findings improve our understanding of biofilm formation in natural and engineered environmental systems and will contribute to future work ranging from pathogen migration in the environment to control of biofouling on engineered surfaces.

  20. Relationship between Microtubule Network Structure and Intracellular Transport in Cultured Endothelial Cells Affected by Shear Stress

    NASA Astrophysics Data System (ADS)

    Kudo, Susumu; Ikezawa, Kenji; Ikeda, Mariko; Tanishita, Kazuo

    Endothelial cells (ECs) that line the inner surface of blood vessels are barriers to the transport of various substances into or from vessel walls, and are continuously exposed to shear stress induced by blood flow in vivo. Shear stress affects the cytoskeleton (e.g., microtubules, microfilaments, intermediate filaments), and affects the transport of macromolecules. Here, the relationship between the microtubule network structure and this transport process for albumin uptake within cultured aortic endothelial cells affected by shear stress was studied. Based on fluorescent images of albumin uptake obtained by using confocal laser scanning microscopy (CLSM), both the microtubule network and albumin uptake in ECs were disrupted by colchicine and were affected by shear stress loading.

  1. Production of cell surface and secreted glycoproteins in mammalian cells.

    PubMed

    Seiradake, Elena; Zhao, Yuguang; Lu, Weixian; Aricescu, A Radu; Jones, E Yvonne

    2015-01-01

    Mammalian protein expression systems are becoming increasingly popular for the production of eukaryotic secreted and cell surface proteins. Here we describe methods to produce recombinant proteins in adherent or suspension human embryonic kidney cell cultures, using transient transfection or stable cell lines. The protocols are easy to scale up and cost-efficient, making them suitable for protein crystallization projects and other applications that require high protein yields. PMID:25502196

  2. Feeding Frequency Affects Cultured Rat Pituitary Cells in Low Gravity

    NASA Technical Reports Server (NTRS)

    Hymer, W. C.; Grindeland, R. E.; Salada, T.; Cenci, R.; Krishnan, K.; Mukai, C.; Nagaoka, S.

    1996-01-01

    In this report, we describe the results of a rat pituitary cell culture experiment done on STS-65 in which the effect of cell feeding on the release of the six anterior pituitary hormones was studied. We found complex microgravity related interactions between the frequency of cell feeding and the quantity and quality (i.e. biological activity) of some of the six hormones released in flight. Analyses of growth hormone (GH) released from cells into culture media on different mission days using gel filtration and ion exchange chromatography yielded qualitatively similar results between ground and flight samples. Lack of cell feeding resulted in extensive cell clumping in flight (but not ground) cultures. Vigorous fibroblast growth occurred in both ground and flight cultures fed 4 times. These results are interpreted within the context of autocrine and or paracrine feedback interactions. Finally the payload specialist successfully prepared a fresh trypsin solution in microgravity, detached the cells from their surface and reinserted them back into the culture chamber. These cells reattached and continued to release hormone in microgravity. In summary, this experiment shows that pituitary cells are microgravity sensitive and that coupled operations routinely associated with laboratory cel1 culture can also be accomplished in low gravity.

  3. Heparan Sulfate Proteoglycans May Promote or Inhibit Cancer Progression by Interacting with Integrins and Affecting Cell Migration

    PubMed Central

    Soares, Mariana A.; Teixeira, Felipe C. O. B.; Fontes, Miguel; Arêas, Ana Lúcia; Leal, Marcelo G.; Pavão, Mauro S. G.; Stelling, Mariana P.

    2015-01-01

    The metastatic disease is one of the main consequences of tumor progression, being responsible for most cancer-related deaths worldwide. This review intends to present and discuss data on the relationship between integrins and heparan sulfate proteoglycans in health and cancer progression. Integrins are a family of cell surface transmembrane receptors, responsible for cell-matrix and cell-cell adhesion. Integrins' main functions include cell adhesion, migration, and survival. Heparan sulfate proteoglycans (HSPGs) are cell surface molecules that play important roles as cell receptors, cofactors, and overall direct or indirect contributors to cell organization. Both molecules can act in conjunction to modulate cell behavior and affect malignancy. In this review, we will discuss the different contexts in which various integrins, such as α5, αV, β1, and β3, interact with HSPGs species, such as syndecans and perlecans, affecting tissue homeostasis. PMID:26558271

  4. Rosmarinic Acid and Melissa officinalis Extracts Differently Affect Glioblastoma Cells

    PubMed Central

    Ramanauskiene, Kristina; Raudonis, Raimondas

    2016-01-01

    Lemon balm (Melissa officinalis L.) has many biological effects but especially important is its neuroprotective activity. The aim of the study is to produce different extracts of Melissa officinalis and analyse their chemical composition and biological properties on rat glioblastoma C6 cells. Results revealed that rosmarinic acid (RA) is the predominant compound of lemon balm extracts. RA has cytotoxic effect on glioblastoma cells (LC50 290.5 μM after the incubation of 24 h and LC50 171.3 μM after 48 h). RA at concentration 80–130 μM suppresses the cell proliferation and has an antioxidant effect. 200 μM and higher concentrations of RA have a prooxidant effect and initiate cell death through necrosis. The aqueous extract of lemon balm is also enriched in phenolic compounds: protocatechuic, caftaric, caffeic, ferulic, and cichoric acids and flavonoid luteolin-7-glucoside. This extract at concentrations 50 μM–200 μM RA has cytotoxic activity and initiates cell death through apoptosis. Extracts prepared with 70% ethanol contain the biggest amount of active compounds. These extracts have the highest cytotoxic activity on glioblastoma cells. They initiate generation of intracellular ROS and cell death through apoptosis and necrosis. Our data suggest that differently prepared lemon balm extracts differently affect glioblastoma cells and can be used as neuroprotective agents in several therapeutic strategies.

  5. Rosmarinic Acid and Melissa officinalis Extracts Differently Affect Glioblastoma Cells

    PubMed Central

    Ramanauskiene, Kristina; Raudonis, Raimondas

    2016-01-01

    Lemon balm (Melissa officinalis L.) has many biological effects but especially important is its neuroprotective activity. The aim of the study is to produce different extracts of Melissa officinalis and analyse their chemical composition and biological properties on rat glioblastoma C6 cells. Results revealed that rosmarinic acid (RA) is the predominant compound of lemon balm extracts. RA has cytotoxic effect on glioblastoma cells (LC50 290.5 μM after the incubation of 24 h and LC50 171.3 μM after 48 h). RA at concentration 80–130 μM suppresses the cell proliferation and has an antioxidant effect. 200 μM and higher concentrations of RA have a prooxidant effect and initiate cell death through necrosis. The aqueous extract of lemon balm is also enriched in phenolic compounds: protocatechuic, caftaric, caffeic, ferulic, and cichoric acids and flavonoid luteolin-7-glucoside. This extract at concentrations 50 μM–200 μM RA has cytotoxic activity and initiates cell death through apoptosis. Extracts prepared with 70% ethanol contain the biggest amount of active compounds. These extracts have the highest cytotoxic activity on glioblastoma cells. They initiate generation of intracellular ROS and cell death through apoptosis and necrosis. Our data suggest that differently prepared lemon balm extracts differently affect glioblastoma cells and can be used as neuroprotective agents in several therapeutic strategies. PMID:27688825

  6. Femtosecond fabricated surfaces for cell biology

    NASA Astrophysics Data System (ADS)

    Day, Daniel; Gu, Min

    2010-08-01

    Microfabrication using femtosecond pulse lasers is enabling access to a range of structures, surfaces and materials that was not previously available for scientific and engineering applications. The ability to produce micrometre sized features directly in polymer and metal substrates is demonstrated with applications in cell biology. The size, shape and aspect ratio of the etched features can be precisely controlled through the manipulation of the fluence of the laser etching process with respect to the properties of the target material. Femtosecond laser etching of poly(methyl methacrylate) and aluminium substrates has enabled the production of micrometre resolution moulds that can be accurately replicated using soft lithography. The moulded surfaces are used in the imaging of T cells and demonstrate the improved ability to observe biological events over time periods greater than 10 h. These results indicate the great potential femtosecond pulse lasers may have in the future manufacturing of microstructured surfaces and devices.

  7. Living Toroids - Cells on Toroidal Surfaces

    NASA Astrophysics Data System (ADS)

    Chang, Ya-Wen; Angelini, Thomas; Marquez, Samantha; Kim, Harold; Fernandez-Nieves, Alberto

    2014-03-01

    Cellular environment influences a multitude of cellular functions by providing chemical and physical signals that modulate cell behavior, dynamics, development, and eventually survival. Substrate mechanics has been recognized as one of the important physical cues that governs cell behavior at single cell level as well as in collective cell motion. Past research has suggested several contact-guided behaviors to be the result of surface curvature. However, studies on the effect of curvature are relatively scarce likely due to the difficulty in generating substrates with well-defined curvature. Here we describe the generation of toroidal droplets, which unlike spherical droplets, have regions of both positive and negative Gaussian curvature. Additionally, the range of curvatures can be controlled by varying the size and aspect ratio of the torus. Cells are either encapsulated inside toroidal droplets or located on toroidal hydrogel surfaces. Preliminary studies use B. Subtilis to study the organization of bacteria biofilms. When confined in droplets surrounded by yield-stress fluid, bacteria self-organize into heterogeneous biofilm at fluid- substrate interface. It is found that the surface curvature in the sub-millimeter scale has little effect on biofilm architecture.

  8. Solar cell having improved front surface metallization

    SciTech Connect

    Lillington, D.R.; Mardesich, N.; Dill, H.G.; Garlick, G.F.J.

    1987-09-15

    This patent describes a solar cell comprising: a first layer of gallium arsenide semiconductor material of an N+ conductivity; a second layer of gallium arsenide semiconductor material of an N conductivity overlying the first layer; a third layer of gallium arsenide semiconductor material of a P conductivity overlying the N conductivity layer and forming a P-N junction therebetween. A layer of aluminium gallium arsenide semiconductor material of a p conductivity overlying the front major surface of the P conductivity third layer and having an exposed surface essentially parallel to the front major surface and at least one edge; a plurality of metallic contact lines made of a first metal alloy composition and being spaced apart by a first predetermined distance traversing the exposed surface and extending through the aluminium gallium arsenide layer to the front major surface and making electrical contact to the third layer; a plurality of longitudinally disposed metallic grid lines made of a second metal alloy composition and being spaced apart by a second predetermined distance located on the exposed surface of the aluminium gallium arsenide layer and which cross the metallic contact lines and make electrical contact to the metallic lines; a flat metallic strip disposed on the aluminium gallium arsenide layer exposed surface near the edge, the strip electrically coupling the metallic grid lines to one another; and a back contact located on the back major surface.

  9. Engineering novel cell surface chemistry for selective tumor cell targeting

    SciTech Connect

    Bertozzi, C.R. |

    1997-12-31

    A common feature of many different cancers is the high expression level of the two monosaccharides sialic acid and fucose within the context of cell-surface associated glycoconjugates. A correlation has been made between hypersialylation and/or hyperfucosylation and the highly metastatic phenotype. Thus, a targeting strategy based on sialic acid or fucose expression would be a powerful tool for the development of new cancer cell-selective therapies and diagnostic agents. We have discovered that ketone groups can be incorporated metabolically into cell-surface associated sialic acids. The ketone is can be covalently ligated with hydrazide functionalized proteins or small molecules under physiological conditions. Thus, we have discovered a mechanism to selectively target hydrazide conjugates to highly sialylated cells such as cancer cells. Applications of this technology to the generation of novel cancer cell-selective toxins and MRI contrast reagents will be discussed, in addition to progress towards the use of cell surface fucose residues as vehicles for ketone expression.

  10. Factors affecting white cell content in platelet concentrates.

    PubMed

    Champion, A B; Carmen, R A

    1985-01-01

    In this study, we investigated the factors affecting white cell content in platelet concentrates. White cell yields can be reduced 50 percent by stopping platelet-rich plasma expression when the interface is 1 cm from the top of the blood bag as compared to stopping expression when the interface reaches the top of the bag. Further reductions can be achieved by careful handling during transfer of units from the centrifuge cups to expressors (after the first spin) and by carefully balancing units against each other to ensure proper rotor balance during the first spin. Following these suggestions, blood banks should be able to produce platelet concentrates with white cell yields between 2 and 6 X 10(7) and with platelet yields between 7.5 and 8 X 10(10). Transfusion of this product may reduce febrile reactions and lower the incidence of alloimmunizations. PMID:4024231

  11. Noggin 1 overexpression in retinal progenitors affects bipolar cell generation.

    PubMed

    Messina, Andrea; Bridi, Simone; Bozza, Angela; Bozzi, Yuri; Baudet, Marie-Laure; Casarosa, Simona

    2016-01-01

    Waves of Bone Morphogenetic Proteins (BMPs) and their antagonists are present during initial eye development, but their possible roles in retinogenesis are still unknown. We have recently shown that noggin 1, a BMP antagonist, renders pluripotent cells able to differentiate into retinal precursors, and might be involved in the maintenance of retinal structures in the adult vertebrate eye. Here, we report that noggin 1, differently from noggin 2 and noggin 4, is expressed during all phases of Xenopus laevis retinal development. Gain-of-function experiments by electroporation in the optic vesicle show that overexpression of noggin 1 significantly decreases the number of bipolar cells in the inner nuclear layer of the retina, without significantly affecting the generation of the other retinal cell types. Our data suggest that BMP signaling could be involved in the differentiation of retinal progenitors into specific retinal subtypes during late phases of vertebrate retinal development. PMID:27389985

  12. Surface coating affects behavior of metallic nanoparticles in a biological environment.

    PubMed

    Jurašin, Darija Domazet; Ćurlin, Marija; Capjak, Ivona; Crnković, Tea; Lovrić, Marija; Babič, Michal; Horák, Daniel; Vinković Vrček, Ivana; Gajović, Srećko

    2016-01-01

    Silver (AgNPs) and maghemite, i.e., superparamagnetic iron oxide nanoparticles (SPIONs) are promising candidates for new medical applications, which implies the need for strict information regarding their physicochemical characteristics and behavior in a biological environment. The currently developed AgNPs and SPIONs encompass a myriad of sizes and surface coatings, which affect NPs properties and may improve their biocompatibility. This study is aimed to evaluate the effects of surface coating on colloidal stability and behavior of AgNPs and SPIONs in modelled biological environments using dynamic and electrophoretic light scattering techniques, as well as transmission electron microscopy to visualize the behavior of the NP. Three dispersion media were investigated: ultrapure water (UW), biological cell culture medium without addition of protein (BM), and BM supplemented with common serum protein (BMP). The obtained results showed that different coating agents on AgNPs and SPIONs produced different stabilities in the same biological media. The combination of negative charge and high adsorption strength of coating agents proved to be important for achieving good stability of metallic NPs in electrolyte-rich fluids. Most importantly, the presence of proteins provided colloidal stabilization to metallic NPs in biological fluids regardless of their chemical composition, surface structure and surface charge. In addition, an assessment of AgNP and SPION behavior in real biological fluids, rat whole blood (WhBl) and blood plasma (BlPl), revealed that the composition of a biological medium is crucial for the colloidal stability and type of metallic NP transformation. Our results highlight the importance of physicochemical characterization and stability evaluation of metallic NPs in a variety of biological systems including as many NP properties as possible.

  13. Surface coating affects behavior of metallic nanoparticles in a biological environment

    PubMed Central

    Jurašin, Darija Domazet; Ćurlin, Marija; Capjak, Ivona; Crnković, Tea; Lovrić, Marija; Babič, Michal; Horák, Daniel; Gajović, Srećko

    2016-01-01

    Summary Silver (AgNPs) and maghemite, i.e., superparamagnetic iron oxide nanoparticles (SPIONs) are promising candidates for new medical applications, which implies the need for strict information regarding their physicochemical characteristics and behavior in a biological environment. The currently developed AgNPs and SPIONs encompass a myriad of sizes and surface coatings, which affect NPs properties and may improve their biocompatibility. This study is aimed to evaluate the effects of surface coating on colloidal stability and behavior of AgNPs and SPIONs in modelled biological environments using dynamic and electrophoretic light scattering techniques, as well as transmission electron microscopy to visualize the behavior of the NP. Three dispersion media were investigated: ultrapure water (UW), biological cell culture medium without addition of protein (BM), and BM supplemented with common serum protein (BMP). The obtained results showed that different coating agents on AgNPs and SPIONs produced different stabilities in the same biological media. The combination of negative charge and high adsorption strength of coating agents proved to be important for achieving good stability of metallic NPs in electrolyte-rich fluids. Most importantly, the presence of proteins provided colloidal stabilization to metallic NPs in biological fluids regardless of their chemical composition, surface structure and surface charge. In addition, an assessment of AgNP and SPION behavior in real biological fluids, rat whole blood (WhBl) and blood plasma (BlPl), revealed that the composition of a biological medium is crucial for the colloidal stability and type of metallic NP transformation. Our results highlight the importance of physicochemical characterization and stability evaluation of metallic NPs in a variety of biological systems including as many NP properties as possible. PMID:26977382

  14. ALDH isozymes downregulation affects cell growth, cell motility and gene expression in lung cancer cells

    PubMed Central

    Moreb, Jan S; Baker, Henry V; Chang, Lung-Ji; Amaya, Maria; Lopez, M Cecilia; Ostmark, Blanca; Chou, Wayne

    2008-01-01

    Background Aldehyde dehydrogenase isozymes ALDH1A1 and ALDH3A1 are highly expressed in non small cell lung cancer. Neither the mechanisms nor the biologic significance for such over expression have been studied. Methods We have employed oligonucleotide microarrays to analyze changes in gene profiles in A549 lung cancer cell line in which ALDH activity was reduced by up to 95% using lentiviral mediated expression of siRNA against both isozymes (Lenti 1+3). Stringent analysis methods were used to identify gene expression patterns that are specific to the knock down of ALDH activity and significantly different in comparison to wild type A549 cells (WT) or cells similarly transduced with green fluorescent protein (GFP) siRNA. Results We confirmed significant and specific down regulation of ALDH1A1 and ALDH3A1 in Lenti 1+3 cells and in comparison to 12 other ALDH genes detected. The results of the microarray analysis were validated by real time RT-PCR on RNA obtained from Lenti 1+3 or WT cells treated with ALDH activity inhibitors. Detailed functional analysis was performed on 101 genes that were significantly different (P < 0.001) and their expression changed by ≥ 2 folds in the Lenti 1+3 group versus the control groups. There were 75 down regulated and 26 up regulated genes. Protein binding, organ development, signal transduction, transcription, lipid metabolism, and cell migration and adhesion were among the most affected pathways. Conclusion These molecular effects of the ALDH knock-down are associated with in vitro functional changes in the proliferation and motility of these cells and demonstrate the significance of ALDH enzymes in cell homeostasis with a potentially significant impact on the treatment of lung cancer. PMID:19025616

  15. Friction, Wear, and Surface Damage of Metals as Affected by Solid Surface Films

    NASA Technical Reports Server (NTRS)

    Bisson, Edmond E; Johnson, Robert L; Swikert, Max A; Godfrey, Douglas

    1956-01-01

    As predicted by friction theory, experiments showed that friction and surface damage of metals can be reduced by solid surface films. The ability of materials to form surface films that prevent welding was a very important factor in wear of dry and boundary lubricated surfaces. Films of graphitic carbon on cast irons, nio on nickel alloys, and feo and fe sub 3 o sub 4 on ferrous materials were found to be beneficial. Abrasive films such as fe sub 2 o sub 3 or moo sub 3 were definitely detrimental. It appears that the importance of oxide films to friction and wear processes has not been fully appreciated.

  16. Culture materials affect ex vivo expansion of hematopoietic progenitor cells.

    PubMed

    LaIuppa, J A; McAdams, T A; Papoutsakis, E T; Miller, W M

    1997-09-01

    Ex vivo expansion of hematopoietic cells is important for applications such as cancer treatment, gene therapy, and transfusion medicine. While cell culture systems are widely used to evaluate the biocompatibility of materials for implantation, the ability of materials to support proliferation of primary human cells in cultures for reinfusion into patients has not been addressed. We screened a variety of commercially available polymer (15 types), metal (four types), and glass substrates for their ability to support expansion of hematopoietic cells when cultured under conditions that would be encountered in a clinical setting. Cultures of peripheral blood (PB) CD34+ cells and mononuclear cells (MNC) were evaluated for expansion of total cells and colony-forming unit-granulocyte monocyte (CFU-GM; progenitors committed to the granulocyte and/or monocyte lineage). Human hematopoietic cultures in serum-free medium were found to be extremely sensitive to the substrate material. The only materials tested that supported expansion at or near the levels of polystyrene were tissue culture polystyrene, Teflon perfluoroalkoxy, Teflon fluorinated ethylene propylene, cellulose acetate, titanium, new polycarbonate, and new polymethylpentene. MNC were less sensitive to the substrate materials than the primitive CD34+ progenitors, although similar trends were seen for expansion of the two cell populations on the substrates tested. CFU-GM expansion was more sensitive to substrate materials than was total cell expansion. The detrimental effects of a number of the materials on hematopoietic cultures appear to be caused by protein adsorption and/or leaching of toxins. Factors such as cleaning, sterilization, and reuse significantly affected the performance of some materials as culture substrates. We also used PB CD34+ cell cultures to examine the biocompatibility of gas-permeable cell culture and blood storage bags and several types of tubing commonly used with biomedical equipment

  17. Cell surface proteoglycan associates with the cytoskeleton at the basolateral cell surface of mouse mammary epithelial cells

    PubMed Central

    1986-01-01

    The cell surface proteoglycan on normal murine mammary gland mouse mammary epithelial cells consists of an ectodomain bearing heparan and chondroitin sulfate chains and a lipophilic domain that is presumed to be intercalated into the plasma membrane. Because the ectodomain binds to matrix components produced by stromal cells with specificity and high affinity, we have proposed that the cell surface proteoglycan is a matrix receptor that binds epithelial cells to their underlying basement membrane. We now show that the proteoglycan surrounds cells grown in subconfluent or newly confluent monolayers, but becomes restricted to the basolateral surface of cells that have been confluent for a week or more; Triton X-100 extraction distinguishes three fractions of cell surface proteoglycan: a fraction released by detergent and presumed to be free in the membrane, a fraction bound via a salt-labile linkage, and a nonextractable fraction; the latter two fractions co-localize with actin filament bundles at the basal cell surface; and when proteoglycans at the apical cell surface are cross- linked by antibodies, they initially assimilate into detergent- resistant, immobile clusters that are subsequently aggregated by the cytoskeleton. These findings suggest that the proteoglycan, initially present on the entire surface and free in the plane of the membrane, becomes sequestered at the basolateral cell surface and bound to the actin-rich cytoskeleton as the cells become polarized in vitro. Binding of matrix components may cross-link proteoglycans at the basal cell surface and cause them to associate with the actin cytoskeleton, providing a mechanism by which the cell surface proteoglycan acts as a matrix receptor to stabilize the morphology of epithelial sheets. PMID:3025223

  18. Melanopsin, photosensitive ganglion cells, and seasonal affective disorder.

    PubMed

    Roecklein, Kathryn A; Wong, Patricia M; Miller, Megan A; Donofry, Shannon D; Kamarck, Marissa L; Brainard, George C

    2013-03-01

    In two recent reports, melanopsin gene variations were associated with seasonal affective disorder (SAD), and in changes in the timing of sleep and activity in healthy individuals. New studies have deepened our understanding of the retinohypothalamic tract, which translates environmental light received by the retina into neural signals sent to a set of nonvisual nuclei in the brain that are responsible for functions other than sight including circadian, neuroendocrine and neurobehavioral regulation. Because this pathway mediates seasonal changes in physiology, behavior, and mood, individual variations in the pathway may explain why approximately 1-2% of the North American population develops mood disorders with a seasonal pattern (i.e., Major Depressive and Bipolar Disorders with a seasonal pattern, also known as seasonal affective disorder/SAD). Components of depression including mood changes, sleep patterns, appetite, and cognitive performance can be affected by the biological and behavioral responses to light. Specifically, variations in the gene sequence for the retinal photopigment, melanopsin, may be responsible for significant increased risk for mood disorders with a seasonal pattern, and may do so by leading to changes in activity and sleep timing in winter. The retinal sensitivity of SAD is hypothesized to be decreased compared to controls, and that further decrements in winter light levels may combine to trigger depression in winter. Here we outline steps for new research to address the possible role of melanopsin in seasonal affective disorder including chromatic pupillometry designed to measure the sensitivity of melanopsin containing retinal ganglion cells.

  19. Cell surface receptors for CCN proteins.

    PubMed

    Lau, Lester F

    2016-06-01

    The CCN family (CYR61; CTGF; NOV; CCN1-6; WISP1-3) of matricellular proteins in mammals is comprised of six homologous members that play important roles in development, inflammation, tissue repair, and a broad range of pathological processes including fibrosis and cancer. Despite considerable effort to search for a high affinity CCN-specific receptor akin to growth factor receptors, no such receptor has been found. Rather, CCNs bind several groups of multi-ligand receptors as characteristic of other matricellular proteins. The most extensively documented among CCN-binding receptors are integrins, including αvβ3, αvβ5, α5β1, α6β1, αIIbβ3, αMβ2, and αDβ2, which mediate diverse CCN functions in various cell types. CCNs also bind cell surface heparan sulfate proteoglycans (HSPGs), low density liproprotein receptor-related proteins (LRPs), and the cation-independent mannose-6-phosphate (M6P) receptor, which are endocytic receptors that may also serve as co-receptors in cooperation with other cell surface receptors. CCNs have also been reported to bind FGFR-2, Notch, RANK, and TrkA, potentially altering the affinities of these receptors for their ligands. The ability of CCNs to bind a multitude of receptors in various cell types may account for the remarkable versatility of their functions, and underscore the diverse signaling pathways that mediate their activities.

  20. Nanoparticle energy transfer on the cell surface.

    PubMed

    Bene, László; Szentesi, Gergely; Mátyus, László; Gáspár, Rezso; Damjanovich, Sándor

    2005-01-01

    Membrane topology of receptors plays an important role in shaping transmembrane signalling of cells. Among the methods used for characterizing receptor clusters, fluorescence resonance energy transfer between a donor and acceptor fluorophore plays a unique role based on its capability of detecting molecular level (2-10 nm) proximities of receptors in physiological conditions. Recent development of biotechnology has made possible the usage of colloidal gold particles in a large size range for specific labelling of cells for the purposes of electron microscopy. However, by combining metal and fluorophore labelling of cells, the versatility of metal-fluorophore interactions opens the way for new applications by detecting the presence of the metal particles by the methods of fluorescence spectroscopy. An outstanding feature of the metal nanoparticle-fluorophore interaction is that the metal particle can enhance spontaneous emission of the fluorophore in a distance-dependent fashion, in an interaction range essentially determined by the size of the nanoparticle. In our work enhanced fluorescence of rhodamine and cyanine dyes was observed in the vicinity of immunogold nanoparticles on the surface of JY cells in a flow cytometer. The dyes and the immunogold were targetted to the cell surface receptors MHCI, MHCII, transferrin receptor and CD45 by monoclonal antibodies. The fluorescence enhancement was sensitive to the wavelength of the exciting light, the size and amount of surface bound gold beads, as well as the fluorophore-nanoparticle distance. The intensity of 90 degrees scattering of the incident light beam was enhanced by the immunogold in a concentration and size-dependent fashion. The 90 degrees light scattering varied with the wavelength of the incident light in a manner characteristic to gold nanoparticles of the applied sizes. A reduction in photobleaching time constant of the cyanine dye was observed in the vicinity of gold particles in a digital imaging

  1. Genome rearrangement affects RNA virus adaptability on prostate cancer cells

    PubMed Central

    Pesko, Kendra; Voigt, Emily A.; Swick, Adam; Morley, Valerie J.; Timm, Collin; Yin, John; Turner, Paul E.

    2015-01-01

    Gene order is often highly conserved within taxonomic groups, such that organisms with rearranged genomes tend to be less fit than wild type gene orders, and suggesting natural selection favors genome architectures that maximize fitness. But it is unclear whether rearranged genomes hinder adaptability: capacity to evolutionarily improve in a new environment. Negative-sense non-segmented RNA viruses (order Mononegavirales) have specific genome architecture: 3′ UTR – core protein genes – envelope protein genes – RNA-dependent RNA-polymerase gene – 5′ UTR. To test how genome architecture affects RNA virus evolution, we examined vesicular stomatitis virus (VSV) variants with the nucleocapsid (N) gene moved sequentially downstream in the genome. Because RNA polymerase stuttering in VSV replication causes greater mRNA production in upstream genes, N gene translocation toward the 5′ end leads to stepwise decreases in N transcription, viral replication and progeny production, and also impacts the activation of type 1 interferon mediated antiviral responses. We evolved VSV gene-order variants in two prostate cancer cell lines: LNCap cells deficient in innate immune response to viral infection, and PC-3 cells that mount an IFN stimulated anti-viral response to infection. We observed that gene order affects phenotypic adaptability (reproductive growth; viral suppression of immune function), especially on PC-3 cells that strongly select against virus infection. Overall, populations derived from the least-fit ancestor (most-altered N position architecture) adapted fastest, consistent with theory predicting populations with low initial fitness should improve faster in evolutionary time. Also, we observed correlated responses to selection, where viruses improved across both hosts, rather than suffer fitness trade-offs on unselected hosts. Whole genomics revealed multiple mutations in evolved variants, some of which were conserved across selective environments for a

  2. Nano-patterned SU-8 surface using nanosphere-lithography for enhanced neuronal cell growth

    NASA Astrophysics Data System (ADS)

    Kim, Eunhee; Yoo, Seung-Jun; Kim, Eunjung; Kwon, Tae-Hwan; Zhang, Li; Moon, Cheil; Choi, Hongsoo

    2016-04-01

    Mimicking the nanoscale surface texture of the extracellular matrix can affect the regulation of cellular behavior, including adhesion, differentiation, and neurite outgrowth. In this study, SU-8-based polymer surfaces with well-ordered nanowell arrays were fabricated using nanosphere lithography with polystyrene nanoparticles. We show that the SU-8 surface with nanowells resulted in similar neuronal development of rat pheochromocytoma (PC12) cells compared with an unpatterned poly-L-lysine (PLL)-coated SU-8 surface. Additionally, even after soaking the substrate in cell culture medium for two weeks, cells on the nanowell SU-8 surface showed long-term neurite outgrowth compared to cells on the PLL-coated SU-8 surface. The topographical surface modification of the nanowell array demonstrates potential as a replacement for cell adhesive material coatings such as PLL, for applications requiring long-term use of polymer-based implantable devices.

  3. Surface free energy predominates in cell adhesion to hydroxyapatite through wettability.

    PubMed

    Nakamura, Miho; Hori, Naoko; Ando, Hiroshi; Namba, Saki; Toyama, Takeshi; Nishimiya, Nobuyuki; Yamashita, Kimihiro

    2016-05-01

    The initial adhesion of cells to biomaterials is critical in the regulation of subsequent cell behaviors. The purpose of this study was to investigate a mechanism through which the surface wettability of biomaterials can be improved and determine the effects of biomaterial surface characteristics on cellular behaviors. We investigated the surface characteristics of various types of hydroxyapatite after sintering in different atmospheres and examined the effects of various surface characteristics on cell adhesion to study cell-biomaterial interactions. Sintering atmosphere affects the polarization capacity of hydroxyapatite by changing hydroxide ion content and grain size. Compared with hydroxyapatite sintered in air, hydroxyapatite sintered in saturated water vapor had a higher polarization capacity that increased surface free energy and improved wettability, which in turn accelerated cell adhesion. We determined the optimal conditions of hydroxyapatite polarization for the improvement of surface wettability and acceleration of cell adhesion.

  4. Iron affects the structure of cell membrane molecular models.

    PubMed

    Suwalsky, M; Martínez, F; Cárdenas, H; Grzyb, J; Strzałka, K

    2005-03-01

    The effects of Fe(3+) and Fe(2+) on molecular models of biomembranes were investigated. These consisted of bilayers of dimyristoylphosphatidylcholine (DMPC) and of dimyristoylphosphatidylethanolamine (DMPE), classes of phospholipids located in the outer and inner moieties of cell membranes, respectively. X-ray studies showed that very low concentrations of Fe(3+) affected DMPC organization and 10(-3)M induced a total loss of its multilamellar periodic stacking. Experiments carried out with Fe(2+) on DMPC showed weaker effects than those induced by Fe(3+) ions. Similar experiments were performed on DMPE bilayers. Fe(3+) from 10(-7)M up to 10(-4)M had practically no effect on DMPE structure. However, 10(-3)M Fe(3+) induced a deep perturbation of the multilamellar structure of DMPE. However, 10(-3)M Fe(2+) had no effect on DMPE organization practically. Differential scanning calorimetry measurements also revealed different effects of Fe(3+) and Fe(2+) on the phase transition and other thermal properties of the examined lipids. In conclusion, the results obtained indicate that iron ions interact with phospholipid bilayers perturbing their structures. These findings are consistent with the observation that iron ions change cell membrane fluidity and, therefore, affect its functions. PMID:15752465

  5. Nutrient losses in runoff from feedlot surfaces as affected by unconsolidated surface materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beef cattle feedlots contain unconsolidated surface materials (USM) (loose manure pack) that accumulate within feedlot pens during a feeding cycle. The effects of varying amounts of USM on feedlot runoff water quality are not well defined. The objectives of this field investigation were to: a) compa...

  6. CZTSSe thin film solar cells: Surface treatments

    NASA Astrophysics Data System (ADS)

    Joglekar, Chinmay Sunil

    Chalcopyrite semiconducting materials, specifically CZTS, are a promising alternative to traditional silicon solar cell technology. Because of the high absorption coefficient; films of the order of 1 micrometer thickness are sufficient for the fabrication of solar cells. Liquid based synthesis methods are advantageous because they are easily scalable using the roll to roll manufacturing techniques. Various treatments are explored in this study to enhance the performance of the selenized CZTS film based solar cells. Thiourea can be used as a sulfur source and can be used to tune band gap of CZTSSe. Bromine etching can be used to manipulate the thickness of sintered CZTSSe film. The etching treatment creates recombination centers which lead to poor device performance. Various after treatments were used to improve the performance of the devices. It was observed that the performance of the solar cell devices could not be improved by any of the after treatment steps. Other surface treatment processes are explored including KCN etching and gaseous H2S treatments. Hybrid solar cells which included use of CIGS nanoparticles at the interface between CZTSSe and CdS are also explored.

  7. Selection of Antibodies Interfering with Cell Surface Receptor Signaling Using Embryonic Stem Cell Differentiation.

    PubMed

    Melidoni, Anna N; Dyson, Michael R; McCafferty, John

    2016-01-01

    Antibodies able to bind and modify the function of cell surface signaling components in vivo are increasingly being used as therapeutic drugs. The identification of such "functional" antibodies from within large antibody pools is, therefore, the subject of intense research. Here we describe a novel cell-based expression and reporting system for the identification of functional antibodies from antigen-binding populations preselected with phage display. The system involves inducible expression of the antibody gene population from the Rosa-26 locus of embryonic stem (ES) cells, followed by secretion of the antibodies during ES cell differentiation. Target antigens are cell-surface signaling components (receptors or ligands) with a known effect on the direction of cell differentiation (FGFR1 mediating ES cell exit from self renewal in this particular protocol). Therefore, inhibition or activation of these components by functional antibodies in a few elite clones causes a shift in the differentiation outcomes of these clones, leading to their phenotypic selection. Functional antibody genes are then recovered from positive clones and used to produce the purified antibodies, which can be tested for their ability to affect cell fates exogenously. Identified functional antibody genes can be further introduced in different stem cell types. Inducible expression of functional antibodies has a temporally controlled protein-knockdown capability, which can be used to study the unknown role of the signaling pathway in different developmental contexts. Moreover, it provides a means for control of stem cell differentiation with potential in vivo applications.

  8. Shape-memory surfaces for cell mechanobiology

    NASA Astrophysics Data System (ADS)

    Ebara, Mitsuhiro

    2015-02-01

    Shape-memory polymers (SMPs) are a new class of smart materials, which have the capability to change from a temporary shape ‘A’ to a memorized permanent shape ‘B’ upon application of an external stimulus. In recent years, SMPs have attracted much attention from basic and fundamental research to industrial and practical applications due to the cheap and efficient alternative to well-known metallic shape-memory alloys. Since the shape-memory effect in SMPs is not related to a specific material property of single polymers, the control of nanoarchitecture of polymer networks is particularly important for the smart functions of SMPs. Such nanoarchitectonic approaches have enabled us to further create shape-memory surfaces (SMSs) with tunable surface topography at nano scale. The present review aims to bring together the exciting design of SMSs and the ever-expanding range of their uses as tools to control cell functions. The goal for these endeavors is to mimic the surrounding mechanical cues of extracellular environments which have been considered as critical parameters in cell fate determination. The untapped potential of SMSs makes them one of the most exciting interfaces of materials science and cell mechanobiology.

  9. Characterizing cell surface of blooming Microcystis in Lake Taihu, China.

    PubMed

    Liu, Lizhen; Huang, Qi; Qin, Boqiang; Zhu, Guangwei; Wu, Pan; Wu, Yongming

    2016-01-01

    Microcystis occurs as colonies in the natural environment but disaggregates into single cells in laboratory cultures. In order to explore the mechanism of how Microcystis forms colonies, the zeta potentials of Microcystis cells from the laboratory and the field were studied, and the hydrophobicity of Microcystis colonies in different sizes was investigated in Lake Taihu. The incubation experiment indicated that the zeta potentials of Microcystis cells were affected by growth phase and species. The absolute values in exponential phase were lower than those in stationary phase, suggesting that the cells with rapid growth easily formed colonies due to more instability on the cell surface. The values of Microcystis aeruginosa were higher than those of Microcystis flos-aquae, which confirmed that M. aeruginosa prevailed in waters for a longer time and at a larger size compared with M. flos-aquae. In another aspect, the absolute zeta potentials of Microcystis spp. at pH 7.0 decreased from spring to autumn in the field; the values in spring were higher than those in summer, suggesting that a large-sized Microcystis colony would more easily form in summer. Additionally, differences in hydrophobicity exist among Microcystis colonies of various sizes. The surface hydrophobicity of colonies in the <20 μm size class was higher than that of larger colonies. This characteristic allowed small colonies to easily form large colonies to survive better. These results would be helpful to understand the mechanism of the bloom formation, especially the colony formation, in Microcystis. PMID:27232410

  10. Yeast cell surface display for lipase whole cell catalyst and its applications

    SciTech Connect

    Liu, Yun; Zhang, Rui; Lian, Zhongshuai; Wang, Shihui; Wright, Aaron T.

    2014-08-01

    The cell surface display technique allows for the expression of target proteins or peptides on the microbial cell surface by fusing an appropriate protein as an anchoring motif. Yeast display systems, such as Pichia pastoris, Yarowia lipolytica and Saccharomyces cerevisiae, are ideal, alternative and extensive display systems with the advantage of simple genetic manipulation and post-translational modification of expressed heterologous proteins. Engineered yeasts show high performance characteristics and variant utilizations. Herein, we comprehensively summarize the variant factors affecting lipase whole cell catalyst activity and display efficiency, including the structure and size of target proteins, screening anchor proteins, type and chain length of linkers, and the appropriate matching rules among the above-mentioned display units. Furthermore, we also address novel approaches to enhance stability and activity of recombinant lipases, such as VHb gene co-expression, multi-enzyme co-display technique, and the micro-environmental interference and self-assembly techniques. Finally, we represent the variety of applications of whole cell surface displayed lipases on yeast cells in non-aqueous phases, including synthesis of esters, PUFA enrichment, resolution of chiral drugs, organic synthesis and biofuels. We demonstrate that the lipase surface display technique is a powerful tool for functionalizing yeasts to serve as whole cell catalysts, and increasing interest is providing an impetus for broad application of this technique.

  11. Subnanometric Roughness Affects the Deposition and Mobile Adhesion of Escherichia coli on Silanized Glass Surfaces.

    PubMed

    Sharma, Sumedha; Jaimes-Lizcano, Yuly Andrea; McLay, Ryan B; Cirino, Patrick C; Conrad, Jacinta C

    2016-05-31

    We investigate the deposition and transient adhesion of Escherichia coli on alkyl and fluoroalkyl silanized glass surfaces of different carbon chain lengths. The rate at which bacteria deposit onto these surfaces decreases as the shear stress is increased from 3 to 67 mPa, but trends in the deposition rate across all surfaces cannot be predicted from extended DLVO calculations of the interaction potential. As the surface root-mean-square (rms) roughness increases, the deposition rate increases and the percentage of motile tethered cells decreases. Furthermore, on surfaces of root-mean-square roughness of less than 0.2 nm, bacteria exhibit mobile adhesion, for which surface-associated cells linearly translate distances greater than approximately 1.5 times their average body length along the flow direction. E. coli bacteria with and without flagella exhibit mobile adhesion, indicating that this behavior is not driven by these appendages. Cells that express fimbriae do not exhibit mobile adhesion. These results suggest that even subnanoscale roughness can influence the deposition and transient adhesion of bacteria and imply that strategies to reduce frictional interactions by making cells or surfaces smoother may help to control the initial fouling of surfaces by E. coli bacteria. PMID:27158837

  12. Quantitative comparison of a human cancer cell surface proteome between interphase and mitosis

    PubMed Central

    Özlü, Nurhan; Qureshi, Mohammad H; Toyoda, Yusuke; Renard, Bernhard Y; Mollaoglu, Gürkan; Özkan, Nazlı E; Bulbul, Selda; Poser, Ina; Timm, Wiebke; Hyman, Anthony A; Mitchison, Timothy J; Steen, Judith A

    2015-01-01

    The cell surface is the cellular compartment responsible for communication with the environment. The interior of mammalian cells undergoes dramatic reorganization when cells enter mitosis. These changes are triggered by activation of the CDK1 kinase and have been studied extensively. In contrast, very little is known of the cell surface changes during cell division. We undertook a quantitative proteomic comparison of cell surface-exposed proteins in human cancer cells that were tightly synchronized in mitosis or interphase. Six hundred and twenty-eight surface and surface-associated proteins in HeLa cells were identified; of these, 27 were significantly enriched at the cell surface in mitosis and 37 in interphase. Using imaging techniques, we confirmed the mitosis-selective cell surface localization of protocadherin PCDH7, a member of a family with anti-adhesive roles in embryos. We show that PCDH7 is required for development of full mitotic rounding pressure at the onset of mitosis. Our analysis provided basic information on how cell cycle progression affects the cell surface. It also provides potential pharmacodynamic biomarkers for anti-mitotic cancer chemotherapy. PMID:25476450

  13. Quantitative comparison of a human cancer cell surface proteome between interphase and mitosis.

    PubMed

    Özlü, Nurhan; Qureshi, Mohammad H; Toyoda, Yusuke; Renard, Bernhard Y; Mollaoglu, Gürkan; Özkan, Nazlı E; Bulbul, Selda; Poser, Ina; Timm, Wiebke; Hyman, Anthony A; Mitchison, Timothy J; Steen, Judith A

    2015-01-13

    The cell surface is the cellular compartment responsible for communication with the environment. The interior of mammalian cells undergoes dramatic reorganization when cells enter mitosis. These changes are triggered by activation of the CDK1 kinase and have been studied extensively. In contrast, very little is known of the cell surface changes during cell division. We undertook a quantitative proteomic comparison of cell surface-exposed proteins in human cancer cells that were tightly synchronized in mitosis or interphase. Six hundred and twenty-eight surface and surface-associated proteins in HeLa cells were identified; of these, 27 were significantly enriched at the cell surface in mitosis and 37 in interphase. Using imaging techniques, we confirmed the mitosis-selective cell surface localization of protocadherin PCDH7, a member of a family with anti-adhesive roles in embryos. We show that PCDH7 is required for development of full mitotic rounding pressure at the onset of mitosis. Our analysis provided basic information on how cell cycle progression affects the cell surface. It also provides potential pharmacodynamic biomarkers for anti-mitotic cancer chemotherapy.

  14. Mechanisms of surface runoff genesis on a subsurface drained soil affected by surface crusting: A field investigation

    NASA Astrophysics Data System (ADS)

    Augeard, Bénédicte; Kao, Cyril; Chaumont, Cédric; Vauclin, Michel

    Artificial drainage has been subject to widespread criticism because of its impact on water quality and because there is suspicion that it may have detrimental effects on flood genesis. The present work aims at a better understanding of the mechanisms controlling infiltration and surface runoff genesis, particularly in soils with artificial drainage and affected by surface crusting. A field experiment was conducted during one drainage season (November 2003-March 2004) in the Brie region (80 km east of Paris, France) on a subsurface drained silty soil. Water table elevation and surface runoff were monitored above the drain and at midpoint between drains. Soil water pressure head was measured at various depths and locations between the midpoint and the drain. Soil surface characteristics (microtopography and degree of structural and sedimentary crust development) were recorded regularly on the experimental site and on other plots of various drainage intensities. The results show that the first surface runoff events were induced by high water table. However, runoff was higher at midpoint between the drains because water table reached the soil surface at that point, thus considerably reducing infiltration capacity compared to that above the drain. Comparing different plots, the area with older drainage installation (1948) yielded the most surface runoff. Wider drain spacing, smaller drain depth and possible plugging may have led to a greater area of saturated soil between drains. During the winter period, the impact of raindrops induced the formation of a structural crust on the soil surface. Furthermore, the development of the sedimentary crust, which was favored by water actually flowing on the soil surface during the high water table periods could be correlated with surface runoff volume. The formation of this crust had a significant impact on runoff occurrence at the end of the winter. Therefore, poorly drained fields presented more favorable conditions for both

  15. Tricellulin deficiency affects tight junction architecture and cochlear hair cells

    PubMed Central

    Nayak, Gowri; Lee, Sue I.; Yousaf, Rizwan; Edelmann, Stephanie E.; Trincot, Claire; Van Itallie, Christina M.; Sinha, Ghanshyam P.; Rafeeq, Maria; Jones, Sherri M.; Belyantseva, Inna A.; Anderson, James M.; Forge, Andrew; Frolenkov, Gregory I.; Riazuddin, Saima

    2013-01-01

    The two compositionally distinct extracellular cochlear fluids, endolymph and perilymph, are separated by tight junctions that outline the scala media and reticular lamina. Mutations in TRIC (also known as MARVELD2), which encodes a tricellular tight junction protein known as tricellulin, lead to nonsyndromic hearing loss (DFNB49). We generated a knockin mouse that carries a mutation orthologous to the TRIC coding mutation linked to DFNB49 hearing loss in humans. Tricellulin was absent from the tricellular junctions in the inner ear epithelia of the mutant animals, which developed rapidly progressing hearing loss accompanied by loss of mechanosensory cochlear hair cells, while the endocochlear potential and paracellular permeability of a biotin-based tracer in the stria vascularis were unaltered. Freeze-fracture electron microscopy revealed disruption of the strands of intramembrane particles connecting bicellular and tricellular junctions in the inner ear epithelia of tricellulin-deficient mice. These ultrastructural changes may selectively affect the paracellular permeability of ions or small molecules, resulting in a toxic microenvironment for cochlear hair cells. Consistent with this hypothesis, hair cell loss was rescued in tricellulin-deficient mice when generation of normal endolymph was inhibited by a concomitant deletion of the transcription factor, Pou3f4. Finally, comprehensive phenotypic screening showed a broader pathological phenotype in the mutant mice, which highlights the non-redundant roles played by tricellulin. PMID:23979167

  16. Effect of surface potential on epithelial cell adhesion, proliferation and morphology.

    PubMed

    Chang, Hsun-Yun; Kao, Wei-Lun; You, Yun-Wen; Chu, Yi-Hsuan; Chu, Kuo-Jui; Chen, Peng-Jen; Wu, Chen-Yi; Lee, Yu-Hsuan; Shyue, Jing-Jong

    2016-05-01

    Cell adhesion is the basis of individual cell survival, division and motility. Hence, understanding the effects that the surface properties have on cell adhesion, proliferation and morphology are crucial. In particular, surface charge/potential has been identified as an important factor that affects cell behavior. However, how cells respond to incremental changes in surface potential remains unclear. By using binary self-assembled monolayer (SAM) modified Au surfaces that are similar in mechanical/chemical properties and provide a series of surface potentials, the effect of surface potential on the behavior of cells can be studied. In this work, the effect of surface potential on epithelial cells, including human embryonic kidney (HEK293T) and human hepatocellular carcinoma (HepG2), were examined. The results showed that the adhesion density of epithelial cells increased with increasing surface potential, which is similar to but varied more significantly compared with fibroblasts. The proliferation rate is found to be independent of surface potential in both cell types. Furthermore, epithelial cells show no morphological change with respect to surface potential, whereas the morphology of the fibroblasts clearly changed with the surface potential. These differences between the cell types were rationalized by considering the difference in extracellular matrix composition. Laminin-dominant epithelial cells showed higher adhesion density and less morphological change than did fibronectin-dominant fibroblasts because the more significant adsorption of positively charged laminin on the surface enhanced the adhesion of epithelial cells. In contrast, due to the dominance of negatively charged fibronectin that adsorbed weakly on the surface, fibroblasts had to change their morphology to fit the inhomogeneous fibronectin-adsorbed area.

  17. Knowledge discovery of cell-cell and cell-surface interactions

    NASA Astrophysics Data System (ADS)

    Su, Jing

    High-throughput cell culture is an emerging technology that shows promise as a tool for research in tissue engineering, drug discovery, and medical diagnostics. An important, but overlooked, challenge is the integration of experimental methods with information processing suitable for handling large databases of cell-cell and cell-substrate interactions. In this work the traditional global descriptions of cell behaviors and surface characteristics was shown insufficient for investigating short-distance cell-to-cell and cell-to-surface interactions. Traditional summary metrics cannot distinguish information of cell near neighborhood from the average, global features, thus often is not suitable for studying distance-sensitive cell behaviors. The problem of traditional summary metrics was addressed by introducing individual-cell based local metrics that emphasize cell local environment. An individual-cell based local data analysis method was established. Contact inhibition of cell proliferation was used as a benchmark for the effectiveness of the local metrics and the method. Where global, summary metrics were unsuccessful, the local metrics successfully and quantitatively distinguished the contact inhibition effects of MC3T3-E1 cells on PLGA, PCL, and TCPS surfaces. In order to test the new metrics and analysis method in detail, a model of cell contact inhibition was proposed. Monte Carlo simulation was performed for validating the individual-cell based local data analysis method as well as the cell model itself. The simulation results well matched with the experimental observations. The parameters used in the cell model provided new descriptions of both cell behaviors and surface characteristics. Based on the viewpoint of individual cells, the local metrics and local data analysis method were extended to the investigation of cell-surface interactions, and a new high-throughput screening and knowledge discovery method on combinatorial libraries, local cell

  18. Neurite outgrowth of neuroblastoma cells: dependence on adhesion surface--cell surface interactions

    PubMed Central

    1984-01-01

    Neurite outgrowth of C 1300 neuroblastoma cells, which were dispersed from adherent cultures or grown in suspension, was studied on different protein-coated surfaces. Of 29 different surface structures studied, including surfaces treated with various fibronectins, lectins, glycosidases, or glycosyltransferases capable of stimulating fibroblast spreading, only the surfaces coated with plasma fibronectin or with a protein mixture secreted by C6 glioma cells displayed an extensive activity in the sprouting assay. Neurite outgrowth was inhibited by brain gangliosides and by colominic acid (a sialic acid polymer). A 50% inhibition of neurite outgrowth of N18 neuroblasts induced by the glioma cell proteins was observed at the following approximate concentration: 100 microM (0.2 mg/ml) GD1A ganglioside, 20 microM (0.04 mg/ml) GT1B ganglioside, and 5 mg/ml colominic acid. Specificity of inhibition was suggested by the finding that a few polyanionic substances tested were not inhibitory in the sprouting assay, and that the type of gangliosides inhibiting sprouting were found to be major sialoglycolipids of the neuroblasts. A hypothesis is discussed, according to which neurite outgrowth of neuroblasts is stimulated by adhesion involving interactions of the adhesion-mediating protein with cell surface carbohydrates characteristic of brain gangliosides. PMID:6699078

  19. Global transcriptomic analysis of model human cell lines exposed to surface-modified gold nanoparticles: the effect of surface chemistry.

    PubMed

    Grzincic, E M; Yang, J A; Drnevich, J; Falagan-Lotsch, P; Murphy, C J

    2015-01-28

    Gold nanoparticles (Au NPs) are attractive for biomedical applications not only for their remarkable physical properties, but also for the ease of which their surface chemistry can be manipulated. Many applications involve functionalization of the Au NP surface in order to improve biocompatibility, attach targeting ligands or carry drugs. However, changes in cells exposed to Au NPs of different surface chemistries have been observed, and little is known about how Au NPs and their surface coatings may impact cellular gene expression. The gene expression of two model human cell lines, human dermal fibroblasts (HDF) and prostate cancer cells (PC3) was interrogated by microarray analysis of over 14,000 human genes. The cell lines were exposed to four differently functionalized Au NPs: citrate, poly(allylamine hydrochloride) (PAH), and lipid coatings combined with alkanethiols or PAH. Gene functional annotation categories and weighted gene correlation network analysis were used in order to connect gene expression changes to common cellular functions and to elucidate expression patterns between Au NP samples. Coated Au NPs affect genes implicated in proliferation, angiogenesis, and metabolism in HDF cells, and inflammation, angiogenesis, proliferation apoptosis regulation, survival and invasion in PC3 cells. Subtle changes in surface chemistry, such as the initial net charge, lability of the ligand, and underlying layers greatly influence the degree of expression change and the type of cellular pathway affected.

  20. New common variants affecting susceptibility to basal cell carcinoma.

    PubMed

    Stacey, Simon N; Sulem, Patrick; Masson, Gisli; Gudjonsson, Sigurjon A; Thorleifsson, Gudmar; Jakobsdottir, Margret; Sigurdsson, Asgeir; Gudbjartsson, Daniel F; Sigurgeirsson, Bardur; Benediktsdottir, Kristrun R; Thorisdottir, Kristin; Ragnarsson, Rafn; Scherer, Dominique; Hemminki, Kari; Rudnai, Peter; Gurzau, Eugene; Koppova, Kvetoslava; Botella-Estrada, Rafael; Soriano, Virtudes; Juberias, Pablo; Saez, Berta; Gilaberte, Yolanda; Fuentelsaz, Victoria; Corredera, Cristina; Grasa, Matilde; Höiom, Veronica; Lindblom, Annika; Bonenkamp, Johannes J; van Rossum, Michelle M; Aben, Katja K H; de Vries, Esther; Santinami, Mario; Di Mauro, Maria G; Maurichi, Andrea; Wendt, Judith; Hochleitner, Pia; Pehamberger, Hubert; Gudmundsson, Julius; Magnusdottir, Droplaug N; Gretarsdottir, Solveig; Holm, Hilma; Steinthorsdottir, Valgerdur; Frigge, Michael L; Blondal, Thorarinn; Saemundsdottir, Jona; Bjarnason, Hjördis; Kristjansson, Kristleifur; Bjornsdottir, Gyda; Okamoto, Ichiro; Rivoltini, Licia; Rodolfo, Monica; Kiemeney, Lambertus A; Hansson, Johan; Nagore, Eduardo; Mayordomo, José I; Kumar, Rajiv; Karagas, Margaret R; Nelson, Heather H; Gulcher, Jeffrey R; Rafnar, Thorunn; Thorsteinsdottir, Unnur; Olafsson, Jon H; Kong, Augustine; Stefansson, Kari

    2009-08-01

    In a follow-up to our previously reported genome-wide association study of cutaneous basal cell carcinoma (BCC), we describe here several new susceptibility variants. SNP rs11170164, encoding a G138E substitution in the keratin 5 (KRT5) gene, affects risk of BCC (OR = 1.35, P = 2.1 x 10(-9)). A variant at 9p21 near CDKN2A and CDKN2B also confers susceptibility to BCC (rs2151280[C]; OR = 1.19, P = 6.9 x 10(-9)), as does rs157935[T] at 7q32 near the imprinted gene KLF14 (OR = 1.23, P = 5.7 x 10(-10)). The effect of rs157935[T] is dependent on the parental origin of the risk allele. None of these variants were found to be associated with melanoma or fair-pigmentation traits. A melanoma- and pigmentation-associated variant in the SLC45A2 gene, L374F, is associated with risk of both BCC and squamous cell carcinoma. Finally, we report conclusive evidence that rs401681[C] in the TERT-CLPTM1L locus confers susceptibility to BCC but protects against melanoma. PMID:19578363

  1. Calculation of cell volumes and surface areas in MCNP

    SciTech Connect

    Hendricks, J.S.

    1980-01-01

    MCNP is a general Monte Carlo neutron-photon particle transport code which treats an arbitrary three-dimensional configuration of materials in geometric cells bounded by first- and second-degree surfaces, and some special fourth-degree surfaces. It is necessary to calculate cell volumes and surface areas so that cell masses, fluxes, and other important information can be determined. The volume/area calculation in MCNP computes cell volumes and surface areas for cells and surfaces rotationally symmetric about any arbitrary axis. 5 figures, 1 table.

  2. Nanoscale topography and chemistry affect embryonic stem cell self-renewal and early differentiation.

    PubMed

    Lapointe, Vanessa L S; Fernandes, Ana Tiago; Bell, Nia C; Stellacci, Francesco; Stevens, Molly M

    2013-12-01

    Adherent cells respond to a wide range of substrate cues, including chemistry, topography, hydrophobicity, and surface energy. The cell-substrate interface is therefore an important design parameter in regenerative medicine and tissue engineering applications, where substrate cues are used to influence cell behavior. Thin films comprising 4.5 nm (average diameter) gold nanoparticles coated with a mixture of two alkanethiols can confer hemispherical topography and specific chemistry to bulk substrates. The behavior of murine embryonic stem cells (ESCs) on the thin films can then be compared with their behavior on self-assembled monolayers of the same alkanethiols on vapor-deposited gold, which lack the topographical features. Cells cultured both with and without differentiation inhibitors are characterized by immunofluorescence for Oct4 and qPCR for Fgf5, Foxa2, Nanog, Pou5f1, and Sox2. Nanoscale chemistry and topography are found to influence stem cell differentiation, particularly the early differentiation markers, Fgf5 and Foxa2. Nanoscale topography also affects Oct4 localization, whereas the chemical composition of the substrate does not have an effect. It is demonstrated for the first time that ESCs can sense topographical features established by 4.5 nm particles, and these findings suggest that nanoscale chemistry and topography can act synergistically to influence stem cell differentiation. This study furthers the understanding of the effects of these substrate properties, improving our ability to design materials to control stem cell fate.

  3. Oriented cell division affects the global stress and cell packing geometry of a monolayer under stretch.

    PubMed

    Xu, Guang-Kui; Liu, Yang; Zheng, Zhaoliang

    2016-02-01

    Cell division plays a vital role in tissue morphogenesis and homeostasis, and the division plane is crucial for cell fate. For isolated cells, extensive studies show that the orientation of divisions is sensitive to cell shape and the direction of extrinsic mechanical forces. However, it is poorly understood that how the cell divides within a cell monolayer and how the local stress change, due to the division, affects the global stress of epithelial monolayers. Here, we use the vertex dynamics models to investigate the effects of division orientation on the configurations and mechanics of a cell monolayer under stretch. We examine three scenarios of the divisions: dividing along the stretch axis, dividing along the geometric long axis of cells, and dividing at a random angle. It is found that the division along the long cell axis can induce the minimal energy difference, and the global stress of the monolayer after stretch releases more rapidly in this case. Moreover, the long-axis division can result in more random cell orientations and more isotropic cell shapes within the monolayer, comparing with other two cases. This study helps understand the division orientation of cells within a monolayer under mechanical stimuli, and may shed light on linking individual cell's behaviors to the global mechanics and patterns of tissues. PMID:26774292

  4. Oriented cell division affects the global stress and cell packing geometry of a monolayer under stretch.

    PubMed

    Xu, Guang-Kui; Liu, Yang; Zheng, Zhaoliang

    2016-02-01

    Cell division plays a vital role in tissue morphogenesis and homeostasis, and the division plane is crucial for cell fate. For isolated cells, extensive studies show that the orientation of divisions is sensitive to cell shape and the direction of extrinsic mechanical forces. However, it is poorly understood that how the cell divides within a cell monolayer and how the local stress change, due to the division, affects the global stress of epithelial monolayers. Here, we use the vertex dynamics models to investigate the effects of division orientation on the configurations and mechanics of a cell monolayer under stretch. We examine three scenarios of the divisions: dividing along the stretch axis, dividing along the geometric long axis of cells, and dividing at a random angle. It is found that the division along the long cell axis can induce the minimal energy difference, and the global stress of the monolayer after stretch releases more rapidly in this case. Moreover, the long-axis division can result in more random cell orientations and more isotropic cell shapes within the monolayer, comparing with other two cases. This study helps understand the division orientation of cells within a monolayer under mechanical stimuli, and may shed light on linking individual cell's behaviors to the global mechanics and patterns of tissues.

  5. Anabolic androgens affect the competitive interactions in cell migration and adhesion between normal mouse urothelial cells and urothelial carcinoma cells.

    PubMed

    Huang, Chi-Ping; Hsieh, Teng-Fu; Chen, Chi-Cheng; Hung, Xiao-Fan; Yu, Ai-Lin; Chang, Chawnshang; Shyr, Chih-Rong

    2014-09-26

    The urothelium is constantly rebuilt by normal urothelial cells to regenerate damaged tissues caused by stimuli in urine. However, the urothelial carcinoma cells expand the territory by aberrant growth of tumor cells, which migrate and occupy the damaged tissues to spread outside and disrupt the normal cells and organized tissues and form a tumor. Therefore, the interaction between normal urothelial cells and urothelial carcinoma cells affect the initiation and progression of urothelial tumors if normal urothelial cells fail to migrate and adhere to the damages sites to regenerate the tissues. Here, comparing normal murine urothelial cells with murine urothelial carcinoma cells (MBT-2), we found that normal cells had less migration ability than carcinoma cells. And in our co-culture system we found that carcinoma cells had propensity migrating toward normal urothelial cells and carcinoma cells had more advantages to adhere than normal cells. To reverse this condition, we used anabolic androgen, dihyrotestosterone (DHT) to treat normal cells and found that DHT treatment increased the migration ability of normal urothelial cells toward carcinoma cells and the adhesion capacity in competition with carcinoma cells. This study provides the base of a novel therapeutic approach by using anabolic hormone-enforced normal urothelial cells to regenerate the damage urothelium and defend against the occupancy of carcinoma cells to thwart cancer development and recurrence.

  6. Controlling cell-cell interactions using surface acoustic waves.

    PubMed

    Guo, Feng; Li, Peng; French, Jarrod B; Mao, Zhangming; Zhao, Hong; Li, Sixing; Nama, Nitesh; Fick, James R; Benkovic, Stephen J; Huang, Tony Jun

    2015-01-01

    The interactions between pairs of cells and within multicellular assemblies are critical to many biological processes such as intercellular communication, tissue and organ formation, immunological reactions, and cancer metastasis. The ability to precisely control the position of cells relative to one another and within larger cellular assemblies will enable the investigation and characterization of phenomena not currently accessible by conventional in vitro methods. We present a versatile surface acoustic wave technique that is capable of controlling the intercellular distance and spatial arrangement of cells with micrometer level resolution. This technique is, to our knowledge, among the first of its kind to marry high precision and high throughput into a single extremely versatile and wholly biocompatible technology. We demonstrated the capabilities of the system to precisely control intercellular distance, assemble cells with defined geometries, maintain cellular assemblies in suspension, and translate these suspended assemblies to adherent states, all in a contactless, biocompatible manner. As an example of the power of this system, this technology was used to quantitatively investigate the gap junctional intercellular communication in several homotypic and heterotypic populations by visualizing the transfer of fluorescent dye between cells.

  7. Sertoli cell glycosylation patterns as affected by culture age and extracellular matrix.

    PubMed

    Page, K C; Killian, G J; Nyquist, S E

    1990-10-01

    This study evaluated the responsiveness of Sertoli cell glycosylation in vitro to changes in culture age and to the presence of a reconstituted basement membrane (Matrigel) or collagen IV/laminin substrata. Primary Sertoli cell cultures were prepared from 20-day-old rats and incubated with [3H]mannose, a monosaccharide specific for asparagine-linked oligosaccharides. The cells were harvested on Days 4, 6, or 10 of culture life. A supernatant enriched in cell-surface glycopeptides (the trypsinate) and a cell pellet stripped of surface glycoconjugates were evaluated separately. Glycopeptides derived from a Pronase digest of the two samples were fractionated using concanavalin-A lectin affinity chromatography into three major classes: multiantennary complex-type, biantennary complex-type, and high-mannose-type oligosaccharide structures. The proportion of radiolabeled glycopeptides appearing in each of the three classes did not differ between Days 4 and 6 of culture. In contrast, a significant increase in the percentage of radiolabeled glycopeptides containing multiantennary complex-type oligosaccharides was observed in cells harvested from the 10-day-old cultures. In other experiments, Sertoli cells were grown on various substrata: plastic; collagen IV/laminin; or Matrigel, a reconstituted basement membrane (RBM) composed of laminin, collagen IV, proteoglycan sulfate, entactin, and nidogen. Growth on RBM significantly increased multiantennary complex-type oligosaccharide formation compared to plastic, whereas the high-mannose-type glycopeptides increased in cells grown on collagen IV/laminin. These studies suggest that environmental and physiological conditions such as culture age and the presence of extracellular matrix significantly affect glycosylation patterns in Sertoli cell cultures.

  8. Interactions of bluff-body obstacles with turbulent airflows affecting evaporative fluxes from porous surfaces

    NASA Astrophysics Data System (ADS)

    Haghighi, Erfan; Or, Dani

    2015-11-01

    Bluff-body obstacles interacting with turbulent airflows are common in many natural and engineering applications (from desert pavement and shrubs over natural surfaces to cylindrical elements in compact heat exchangers). Even with obstacles of simple geometry, their interactions within turbulent airflows result in a complex and unsteady flow field that affects surface drag partitioning and transport of scalars from adjacent evaporating surfaces. Observations of spatio-temporal thermal patterns on evaporating porous surfaces adjacent to bluff-body obstacles depict well-defined and persistent zonation of evaporation rates that were used to construct a simple mechanistic model for surface-turbulence interactions. Results from evaporative drying of sand surfaces with isolated cylindrical elements (bluff bodies) subjected to constant turbulent airflows were in good agreement with model predictions for localized exchange rates. Experimental and theoretical results show persistent enhancement of evaporative fluxes from bluff-rough surfaces relative to smooth flat surfaces under similar conditions. The enhancement is attributed to formation of vortices that induce a thinner boundary layer over part of the interacting surface footprint. For a practical range of air velocities (0.5-4.0 m/s), low-aspect ratio cylindrical bluff elements placed on evaporating sand surfaces enhanced evaporative mass losses (relative to a flat surface) by up to 300% for high density of elements and high wind velocity, similar to observations reported in the literature. Concepts from drag partitioning were used to generalize the model and upscale predictions to evaporation from surfaces with multiple obstacles for potential applications to natural bluff-rough surfaces.

  9. Engineering Cell Instructive Materials To Control Cell Fate and Functions through Material Cues and Surface Patterning.

    PubMed

    Ventre, Maurizio; Netti, Paolo A

    2016-06-22

    Mastering the interaction between cells and extracellular environment is a fundamental prerequisite in order to engineer functional biomaterial interfaces able to instruct cells with specific commands. Such advanced biomaterials might find relevant application in prosthesis design, tissue engineering, diagnostics and stem cell biology. Because of the highly complex, dynamic, and multifaceted context, a thorough understanding of the cell-material crosstalk has not been achieved yet; however, a variety of material features including biological cues, topography, and mechanical properties have been proved to impact the strength and the nature of the cell-material interaction, eventually affecting cell fate and functions. Although the nature of these three signals may appear very different, they are equated by their participation in the same material-cytoskeleton crosstalk pathway as they regulate cell adhesion events. In this work we present recent and relevant findings on the material-induced cell responses, with a particular emphasis on how the presentation of biochemical/biophysical signals modulates cell behavior. Finally, we summarize and discuss the literature data to draw out unifying elements concerning cell recognition of and reaction to signals displayed by material surfaces.

  10. Factors affecting the cryosurvival of mouse two-cell embryos.

    PubMed

    Critser, J K; Arneson, B W; Aaker, D V; Huse-Benda, A R; Ball, G D

    1988-01-01

    A series of 4 experiments was conducted to examine factors affecting the survival of frozen-thawed 2-cell mouse embryos. Rapid addition of 1.5 M-DMSO (20 min equilibration at 25 degrees C) and immediate, rapid removal using 0.5 M-sucrose did not alter the frequency (mean +/- s.e.m.) of blastocyst development in vitro when compared to untreated controls (90.5 +/- 2.7% vs 95.3 +/- 2.8%). There was an interaction between the temperature at which slow cooling was terminated and thawing rate. Termination of slow cooling (-0.3 degrees C/min) at -40 degrees C with subsequent rapid thawing (approximately 1500 degrees C/min) resulted in a lower frequency of blastocyst development than did termination of slow cooling at -80 degrees C with subsequent slow thawing (+8 degrees C/min) (36.8 +/- 5.6% vs 63.9 +/- 5.7%). When slow cooling was terminated between -40 and -60 degrees C, higher survival rates were achieved with rapid thawing. When slow cooling was terminated below -60 degrees C, higher survival rates were obtained with slow thawing rates. In these comparisons absolute survival rates were highest among embryos cooled below -60 degrees C and thawed slowly. However, when slow cooling was terminated at -32 degrees C, with subsequent rapid warming, survival rates were not different from those obtained when embryos were cooled to -80 degrees C and thawed slowly (52.4 +/- 9.5%, 59.5 +/- 8.6%). These results suggest that optimal cryosurvival rates may be obtained from 2-cell mouse embryos by a rapid or slow thawing procedure, as has been found for mouse preimplantation embryos at later stages.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Interaction of Biofunctionalized Nanoparticles with Receptors on Cell Surfaces: MC Simulations

    NASA Astrophysics Data System (ADS)

    Dormidontova, Elena; Wang, Shihu

    2015-03-01

    One of the areas of active development of modern nanomedicine is drug/gene delivery and imaging application of nanoparticles functionalized by ligands, aptamers or antibodies capable of specific interactions with cell surface receptors. Being a complex multifunctional system different structural aspects of nanoparticles affect their interactions with cell surfaces and the surface properties of cells can be different (e.g. density, distribution and mobility of receptors). Computer simulations allow a systematic investigation of the influence of multiple factors and provide a unified platform for the comparison. Using Monte Carlo simulations we investigate the influence of the nanoparticle properties (nanoparticle size, polymer tether length, polydispersity, density, ligand energy, valence and density) on nanoparticle-cell surface interactions and make predictions regarding favorable nanoparticle design for achieving multiple ligand-receptor binding. We will also discuss the implications of nanoparticle design on the selectivity of attachment to cells with high receptor density while ``ignoring'' cells with a low density of receptors.

  12. Effect of Q-switched Laser Surface Texturing of Titanium on Osteoblast Cell Response

    NASA Astrophysics Data System (ADS)

    Voisey, K. T.; Scotchford, C. A.; Martin, L.; Gill, H. S.

    Titanium and its alloys are important biomedical materials. It is known that the surface texture of implanted medical devices affects cell response. Control of cell response has the potential to enhance fixation of implants into bone and, in other applications, to prevent undesired cell adhesion. The potential use of a 100W Q-switched YAG laser miller (DMG Lasertec 60 HSC) for texturing titanium is investigated. A series of regular features with dimensions of the order of tens of micrometers are generated in the surface of titanium samples and the cell response to these features is determined. Characterisation of the laser milled features reveals features with a lengthscale of a few microns superposed on the larger scale structures, this is attributed to resolidification of molten droplets generated and propelled over the surface by individual laser pulses. The laser textured samples are exposed to osteoblast cells and it is seen that cells do respond to the features in the laser textured surfaces.

  13. Cell-surface carbohydrates of Entamoeba invadens.

    PubMed

    Ribeiro, S; Soares, R M; Alviano, C S; Da Silva, E F; De Souza, W; Angluster, J

    1997-01-01

    Cell-surface carbohydrates of Entamoeba invadens trophozoites were analyzed using (a) a panel of highly purified lectins specific for molecules containing N-acetylglucosamine or sialic acid, N-acetylgalactosamine, galactose, mannose-like residues, and fucose; (b) Escherichia coli K-12 with mannose-sensitive fimbria; (c) enzymatic digestion; and (d) scanning electron microscopy. The presence of galactose (D-Gal) and N-acetylgalactosamine (D-GalNAc) was detected in the amoeba. Previous trypsinization induced the appearance of Glycine max (SBA, specific for D-GalNAc residues)-binding sites, whereas such treatment completely abolished the ability of Ricinus communis (RCAI) and Axinalla polypoides (APP, specific for D-Gal) lectins and partially abolished that of Euonymus europaeus (EEL, specific for D-Gal) lectins to agglutinate the trophozoites. The agglutinating activity of E. coli K-12 adheans with the amoeba was markedly increased after trypsin digestion, indicating that mannose units become exposed after enzyme treatment. These findings were essentially confirmed by scanning electron microscopy. After neuraminidase treatment the parasites became strongly agglutinated with SBA and Arachis hypogaea (PNA, specific for D-Gal) and the cell interaction with Wisteria floribunda (WFH, specific for D-GalNAc) was markedly increased. These results suggest that in E. invadens trophozoites, sialic acid residues are linked to D-Gal and D-GalNAc. PMID:9342747

  14. Cell surface fluctuations studied with defocusing microscopy

    NASA Astrophysics Data System (ADS)

    Agero, U.; Monken, C. H.; Ropert, C.; Gazzinelli, R. T.; Mesquita, O. N.

    2003-05-01

    Phase objects can become visible by slightly defocusing an optical microscope, a technique seldom used as a useful tool. We revisited the theory of defocusing and apply it to our optical microscope with optics corrected at infinity. In our approximation, we obtain that the image contrast is proportional to the two-dimensional (2D) Laplacian of the phase difference introduced by the phase object. If the index of refraction of the phase object is uniform the image obtained from defocusing microscopy is the image of curvature (Laplacian of the local thickness) of the phase object, while standard phase-contrast microscopy gives information about the thickness of the object. We made artificial phase objects and measured image contrasts with defocusing microscopy. Measured contrasts are in excellent agreement with our theoretical model. We use defocusing microscopy to study curvature fluctuations (ruffles) on the surface of macrophages (cell of the innate immune system), and try to correlate mechanical properties of macrophage surface and phagocytosis. We observe large coherent propagating structures: Their shape, speed, density are measured and curvature energy estimated. Inhomogeneities of cytoskeleton refractive index, curvature modulations due to thermal fluctuations and/or periodic changes in cytoskeleton-membrane interactions cause random fluctuations in image contrast. From the temporal and spatial contrast correlation functions, we obtain the decay time and correlation length of such fluctuations that are related to their size and the viscoelastic properties of the cytoskeleton. In order to associate the dynamics of cytoskeleton with the process of phagocytosis, we use an optical tweezers to grab a zymosan particle and put it into contact with the macrophage. We then measure the time for a single phagocytosis event. We add the drug cytochalasin D that depolymerizes the cytoskeleton F-actin network: It inhibits the large propagating coherent fluctuations on the

  15. Plasma of Argon Affects the Earliest Biological Response of Different Implant Surfaces: An In Vitro Comparative Study.

    PubMed

    Canullo, L; Genova, T; Tallarico, M; Gautier, G; Mussano, F; Botticelli, D

    2016-05-01

    The aim of this in vitro study was to evaluate the early cell response and protein adsorption elicited by the argon plasma treatment of different commercially available titanium surfaces via a chair-side device. Sterile disks made of grade 4 titanium (n= 450, 4-mm diameter) with 3 surface topographies (machined, plasma sprayed, and zirconia blasted and acid etched) were allocated to receive 4 testing treatments (2% and 10% protein adsorption and cell adhesion with MC3T3-E1 and MG-63). Furthermore, the specimens were divided to undergo 1) argon plasma treatment (10 W, 1 bar for 12 min) in a plasma reactor, 2) ultraviolet (UV) light treatment for 2 h (positive control group), or 3) no treatment (control group). Pretreatment surface analyses based on a scanning electron microscope and profilometer images were also performed. Profilometric analysis demonstrated that the evaluated specimens perfectly suit the standard parameters. The use of argon plasma was capable of affecting the quantity of proteins adsorbed on the different surfaces, notwithstanding their roughness or topographic features at a low fetal bovine serum concentration (2%). UV light treatment for 2 h attained similar results. Moreover, both the plasma of argon and the UV light demonstrated a significant increase in the number of osteoblasts adherent at 10 min in all tested surfaces. Within its limitations, this in vitro study highlights the potential biological benefits of treating implant surfaces with plasma of argon or UV, irrespective of the roughness of the titanium surface. However, in vivo experiments are needed to confirm these preliminary data and settle the rationale of a treatment that might be clinically relevant in case of bone-reparative deficiencies.

  16. Plasma of Argon Affects the Earliest Biological Response of Different Implant Surfaces: An In Vitro Comparative Study.

    PubMed

    Canullo, L; Genova, T; Tallarico, M; Gautier, G; Mussano, F; Botticelli, D

    2016-05-01

    The aim of this in vitro study was to evaluate the early cell response and protein adsorption elicited by the argon plasma treatment of different commercially available titanium surfaces via a chair-side device. Sterile disks made of grade 4 titanium (n= 450, 4-mm diameter) with 3 surface topographies (machined, plasma sprayed, and zirconia blasted and acid etched) were allocated to receive 4 testing treatments (2% and 10% protein adsorption and cell adhesion with MC3T3-E1 and MG-63). Furthermore, the specimens were divided to undergo 1) argon plasma treatment (10 W, 1 bar for 12 min) in a plasma reactor, 2) ultraviolet (UV) light treatment for 2 h (positive control group), or 3) no treatment (control group). Pretreatment surface analyses based on a scanning electron microscope and profilometer images were also performed. Profilometric analysis demonstrated that the evaluated specimens perfectly suit the standard parameters. The use of argon plasma was capable of affecting the quantity of proteins adsorbed on the different surfaces, notwithstanding their roughness or topographic features at a low fetal bovine serum concentration (2%). UV light treatment for 2 h attained similar results. Moreover, both the plasma of argon and the UV light demonstrated a significant increase in the number of osteoblasts adherent at 10 min in all tested surfaces. Within its limitations, this in vitro study highlights the potential biological benefits of treating implant surfaces with plasma of argon or UV, irrespective of the roughness of the titanium surface. However, in vivo experiments are needed to confirm these preliminary data and settle the rationale of a treatment that might be clinically relevant in case of bone-reparative deficiencies. PMID:26848069

  17. The effect of plasma-nitrided titanium surfaces on osteoblastic cell adhesion, proliferation, and differentiation.

    PubMed

    Ferraz, Emanuela P; Sa, Juliana C; de Oliveira, Paulo T; Alves, Clodomiro; Beloti, Marcio M; Rosa, Adalberto L

    2014-04-01

    In this study, we evaluated the effect of new plasma-nitrided Ti surfaces on the progression of osteoblast cultures, including cell adhesion, proliferation and differentiation. Ti surfaces were treated using two plasma-nitriding protocols, hollow cathode for 3 h (HC 3 h) and 1 h (HC 1 h) and planar for 1 h. Untreated Ti surfaces were used as control. Cells derived from human alveolar and rat calvarial bones were cultured on Ti surfaces for periods of up to 14 days and the following parameters were evaluated: cell morphology, adhesion, spreading and proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization, and gene expression of key osteoblast markers. Plasma-nitriding treatments resulted in Ti surfaces with distinct physicochemical characteristics. The cell adhesion and ALP activity were higher on plasma-nitrided Ti surfaces compared with untreated one, whereas cell proliferation and extracellular matrix mineralization were not affected by the treatments. In addition, the plasma-nitrided Ti surfaces increased the ALP, reduced the osteocalcin and did not affect the Runx2 gene expression. We have shown that HC 3 h and planar Ti surfaces slightly favored the osteoblast differentiation process, and then these surfaces should be considered for further investigation using preclinical models.

  18. Human epithelial cells exposed to functionalized multiwalled carbon nanotubes: interactions and cell surface modifications.

    PubMed

    Fanizza, C; Casciardi, S; Incoronato, F; Cavallo, D; Ursini, C L; Ciervo, A; Maiello, R; Fresegna, A M; Marcelloni, A M; Lega, D; Alvino, A; Baiguera, S

    2015-09-01

    With the expansion of the production and applications of multiwalled carbon nanotubes (MWCNTs) in several industrial and science branches, the potential adverse effects on human health have attracted attention. Numerous studies have been conducted to evaluate how chemical functionalization may affect MWCNT effects; however, controversial data have been reported, showing either increased or reduced toxicity. In particular, the impact of carboxylation on MWCNT cytotoxicity is far from being completely understood. The aim of this work was the evaluation of the modifications induced by carboxylated-MWCNTs (MWCNTs-COOH) on cell surface and the study of cell-MWCNT-COOH interactions by means of field emission scanning electron microscope (FESEM). Human pulmonary epithelial cells (A549) were incubated with MWCNTs-COOH for different exposure times and concentrations (10 μg/mL for 1, 2, 4 h; 5, 10, 20 μg/mL for 24 h). At short incubation time, MWCNTs-COOH were easily observed associated with plasma membrane and in contact with microvilli. After 24 h exposure, FESEM analysis revealed that MWCNTs-COOH induced evident changes in the cellular surface in comparison to control cells: treated cells showed blebs, holes and a depletion of the microvilli density in association with structure modifications, such as widening and/or lengthening. In particular, an increase of cells showing holes and microvilli structure alterations was observed at 20 μg/mL concentration. FESEM analysis showed nanotube agglomerates, of different sizes, entering into the cell with two different mechanisms: inward bending of the membrane followed by nanotube sinking, and nanotube internalization directly through holes. The observed morphological microvilli modifications, induced by MWCNTs-COOH, could affect epithelial functions, such as the control of surfactant production and secretion, leading to pathological conditions, such as alveolar proteinosis. More detailed studies will be, however, necessary to

  19. Impact of enzymatic tissue disintegration on the level of surface molecule expression and immune cell function

    PubMed Central

    Autengruber, A.; Gereke, M.; Hansen, G.; Hennig, C.; Bruder, D.

    2012-01-01

    Immunological characterization of immune cells that reside in specific anatomic compartments often requires their isolation from the respective tissue on the basis of enzymatic tissue disintegration. Applying enzymatic digestion of primary splenocytes, we evaluated the impact of collagenase and dispase, two enzymes that are commonly used for the liberation of immune cells from tissues, on the detectability of 48 immunologically relevant surface molecules that are frequently used for flow cytometric identification, isolation, and characterization of immune cell subsets. Whereas collagenase treatment had only minor effects on surface expression of most molecules tested, dispase treatment considerably affected antibody-mediated detectability of the majority of surface markers in subsequent FACS analyses. This effect was long lasting and, in case of high-dose dispase treatment, evident for the majority of surface molecules even after 24 h of in vitro culture. Of note, high-dose dispase treatment not only affected surface expression of certain molecules but also impaired antigen-specific proliferation of CD4+ and CD8+ T cells. Together, our data indicate that enzymatic tissue disintegration can have profound effects on the expression of a variety of cell-surface molecules with direct consequences for phenotypic analysis, FACS- and MACS-based target cell isolation, and immune cell function in cell culture experiments. PMID:24672679

  20. Facile cell patterning on an albumin-coated surface.

    PubMed

    Yamazoe, Hironori; Uemura, Toshimasa; Tanabe, Toshizumi

    2008-08-19

    Fabrication of micropatterned surfaces to organize and control cell adhesion and proliferation is an indispensable technique for cell-based technologies. Although several successful strategies for creating cellular micropatterns on substrates have been demonstrated, a complex multistep process and requirements for special and expensive equipment or materials limit their prevalence as a general experimental tool. To circumvent these problems, we describe here a novel facile fabrication method for a micropatterned surface for cell patterning by utilizing the UV-induced conversion of the cell adhesive property of albumin, which is the most abundant protein in blood plasma. An albumin-coated surface was prepared by cross-linking albumin with ethylene glycol diglycidyl ether and subsequent casting of the cross-linked albumin solution on the cell culture dish. While cells did not attach to the albumin surface prepared in this way, UV exposure renders the surface cell-adhesive. Thus, surface micropatterning was achieved simply by exposing the albumin-coated surface to UV light through a mask with the desired pattern. Mouse fibroblast L929 cells were inoculated on the patterned albumin substrates, and cells attached and spread in a highly selective manner according to the UV-irradiated pattern. Although detailed investigation of the molecular-level mechanism concerning the change in cell adhesiveness of the albumin-coated surface is required, the present results would give a novel facile method for the fabrication of cell micropatterned surfaces. PMID:18627191

  1. Graphene Oxide Modulates B Cell Surface Phenotype and Impairs Immunoglobulin Secretion in Plasma Cell.

    PubMed

    Xu, Shaohai; Xu, Shengmin; Chen, Shaopeng; Fan, Huadong; Luo, Xun; Yang, Xiaoyao; Wang, Jun; Yuan, Hang; Xu, An; Wu, Lijun

    2016-04-01

    Since discovery, graphene oxide (GO) has been used in all aspects of human life and revealed promising applications in biomedicine. Nevertheless, the potential risks of GO were always being revealed. Although GO was found to induce immune cell death and innate immune response, little is known regarding its toxicity to the specific adaptive immune system that is crucial for protecting against exotic invasion. The B-cell mediated adaptive immune system, which composed of highly specialized cells (B and plasma cell) and specific immune response (antibody response) is the focus in our present study. Using diverse standard immunological techniques, we found that GO modulated B cell surface phenotype, both costimulatory molecules (CD80, CD86 and especially CD40) and antigen presenting molecules (both classical and nonclassical) under the condition without causing cell death. Meanwhile, the terminal differentiated immunoglobulin (Ig) secreting plasma cell was affected by GO, which displayed a less secretion of Ig and more severe ER stress caused by the retention of the secreted form of Ig in cell compartment. The combined data reveal that GO has a particular adverse effect to B cell and the humoral immunity, directly demonstrating the potential risk of GO to the specific adaptive immunity. PMID:27451788

  2. Effect of microfabricated microgroove-surface devices on the morphology of mesenchymal stem cells.

    PubMed

    Zhang, Xiangkai; Aoyama, Tomoki; Yasuda, Takashi; Oike, Makoto; Ito, Akira; Tajino, Junichi; Nagai, Momoko; Fujioka, Rune; Iijima, Hirotaka; Yamaguchi, Shoki; Kakinuma, Norihiro; Kuroki, Hiroshi

    2015-12-01

    The surface of a material that is in contact with cells is known to affect cell morphology and function. To develop an appropriate surface for tendon engineering, we used zigzag microgroove surfaces, which are similar to the tenocyte microenvironment. The purpose of this study was to investigate the effect of microgroove surfaces with different ridge angles (RAs), ridge lengths (RLs), ridge widths (RWs), and groove widths (GWs) on human bone marrow-derived mesenchymal stem cell (MSC) shape. Dishes with microgroove surfaces were fabricated using cyclic olefin polymer by injection-compression molding. The other parameters were fixed, and effects of different RAs (180 - 30 °), RLs (5 - 500 μm), RWs (5 - 500 μm), and GWs (5 - 500 μm) were examined. Changes in the zigzag shape of the cell due to different RAs, RLs, RWs, and GWs were observed by optical microscopy and scanning electron microscopy. Cytoskeletal changes were investigated using Phalloidin immunofluorescence staining. As observed by optical microscopy, MSCs changed to a zigzag shape in response to microgroove surfaces with different ridge and groove properties. . As observed by scanning electron microscopy, the cell shape changed at turns in the microgroove surface. Phalloidin immunofluorescence staining indicated that F-actin, not only in cell filopodia but also inside the cell body, changed orientation to conform to the microgrooves. In conclusion, the use of zigzag microgroove surfaces microfabricated by injection-compression molding demonstrated the property of MSCs to alter their shapes to fit the surface.

  3. Effect of microfabricated microgroove-surface devices on the morphology of mesenchymal stem cells.

    PubMed

    Zhang, Xiangkai; Aoyama, Tomoki; Yasuda, Takashi; Oike, Makoto; Ito, Akira; Tajino, Junichi; Nagai, Momoko; Fujioka, Rune; Iijima, Hirotaka; Yamaguchi, Shoki; Kakinuma, Norihiro; Kuroki, Hiroshi

    2015-12-01

    The surface of a material that is in contact with cells is known to affect cell morphology and function. To develop an appropriate surface for tendon engineering, we used zigzag microgroove surfaces, which are similar to the tenocyte microenvironment. The purpose of this study was to investigate the effect of microgroove surfaces with different ridge angles (RAs), ridge lengths (RLs), ridge widths (RWs), and groove widths (GWs) on human bone marrow-derived mesenchymal stem cell (MSC) shape. Dishes with microgroove surfaces were fabricated using cyclic olefin polymer by injection-compression molding. The other parameters were fixed, and effects of different RAs (180 - 30 °), RLs (5 - 500 μm), RWs (5 - 500 μm), and GWs (5 - 500 μm) were examined. Changes in the zigzag shape of the cell due to different RAs, RLs, RWs, and GWs were observed by optical microscopy and scanning electron microscopy. Cytoskeletal changes were investigated using Phalloidin immunofluorescence staining. As observed by optical microscopy, MSCs changed to a zigzag shape in response to microgroove surfaces with different ridge and groove properties. . As observed by scanning electron microscopy, the cell shape changed at turns in the microgroove surface. Phalloidin immunofluorescence staining indicated that F-actin, not only in cell filopodia but also inside the cell body, changed orientation to conform to the microgrooves. In conclusion, the use of zigzag microgroove surfaces microfabricated by injection-compression molding demonstrated the property of MSCs to alter their shapes to fit the surface. PMID:26573821

  4. Surface roughness and packaging tightness affect calcium lactate crystallization on Cheddar cheese.

    PubMed

    Rajbhandari, P; Kindstedt, P S

    2014-01-01

    Calcium lactate crystals that sometimes form on Cheddar cheese surfaces are a significant expense to manufacturers. Researchers have identified several postmanufacture conditions such as storage temperature and packaging tightness that contribute to crystal formation. Anecdotal reports suggest that physical characteristics at the cheese surface, such as roughness, cracks, and irregularities, may also affect crystallization. The aim of this study was to evaluate the combined effects of surface roughness and packaging tightness on crystal formation in smoked Cheddar cheese. Four 20-mm-thick cross-section slices were cut perpendicular to the long axis of a retail block (~300g) of smoked Cheddar cheese using a wire cutting device. One cut surface of each slice was lightly etched with a cheese grater to create a rough, grooved surface; the opposite cut surface was left undisturbed (smooth). The 4 slices were vacuum packaged at 1, 10, 50, and 90kPa (very tight, moderately tight, loose, very loose, respectively) and stored at 1°C. Digital images were taken at 1, 4, and 8 wk following the first appearance of crystals. The area occupied by crystals and number of discrete crystal regions (DCR) were quantified by image analysis. The experiment was conducted in triplicate. Effects of storage time, packaging tightness, surface roughness, and their interactions were evaluated by repeated-measures ANOVA. Surface roughness, packaging tightness, storage time, and their 2-way interactions significantly affected crystal area and DCR number. Extremely heavy crystallization occurred on both rough and smooth surfaces when slices were packaged loosely or very loosely and on rough surfaces with moderately tight packaging. In contrast, the combination of rough surface plus very tight packaging resulted in dramatic decreases in crystal area and DCR number. The combination of smooth surface plus very tight packaging virtually eliminated crystal formation, presumably by eliminating available

  5. CELL MEMBRANE SURFACE POTENTIAL (PSI 0) PLAYS A DOMINANT ROLE IN THE PHYTOTOXICITY OF COPPER AND ARSENATE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Negative charges at cell membrane surfaces (CMS) create a surface electrical potential (Psi 0) which affects ion concentrations at the CMS and consequently affects the phytotoxicity of metallic cations and metalloid anions in different ways. The zeta potentials of root protoplasts of wheat (Triticu...

  6. Flocculence of Saccharomyces cerevisiae cells is induced by nutrient limitation, with cell surface hydrophobicity as a major determinant.

    PubMed Central

    Smit, G; Straver, M H; Lugtenberg, B J; Kijne, J W

    1992-01-01

    Initiation of flocculation ability of Saccharomyces cerevisiae MPY1 cells was observed at the moment the cells stop dividing because of nitrogen limitation. A shift in concentration of the limiting nutrient resulted in a corresponding shift in cell division and initiation of flocculence. Other limitations also led to initiation of flocculence, with magnesium limitation as the exception. Magnesium-limited S. cerevisiae cells did not flocculate at any stage of growth. Cell surface hydrophobicity was found to be strongly correlated with the ability of the yeast cells to flocculate. Hydrophobicity sharply increased at the end of the logarithmic growth phase, shortly before initiation of flocculation ability. Treatments of cells which resulted in a decrease in hydrophobicity also yielded a decrease in flocculation ability. Similarly, the presence of polycations increased both hydrophobicity and the ability to flocculate. Magnesium-limited cells were found to be strongly affected in cell surface hydrophobicity. A proteinaceous cell surface factor(s) was identified as a flocculin. This heat-stable component had a strong emulsifying activity, and appears to be involved in both cell surface hydrophobicity and in flocculation ability of the yeast cells. PMID:1482191

  7. ZnO Nanoparticles Affect Bacillus subtilis Cell Growth and Biofilm Formation.

    PubMed

    Hsueh, Yi-Huang; Ke, Wan-Ju; Hsieh, Chien-Te; Lin, Kuen-Song; Tzou, Dong-Ying; Chiang, Chao-Lung

    2015-01-01

    Zinc oxide nanoparticles (ZnO NPs) are an important antimicrobial additive in many industrial applications. However, mass-produced ZnO NPs are ultimately disposed of in the environment, which can threaten soil-dwelling microorganisms that play important roles in biodegradation, nutrient recycling, plant protection, and ecological balance. This study sought to understand how ZnO NPs affect Bacillus subtilis, a plant-beneficial bacterium ubiquitously found in soil. The impact of ZnO NPs on B. subtilis growth, FtsZ ring formation, cytosolic protein activity, and biofilm formation were assessed, and our results show that B. subtilis growth is inhibited by high concentrations of ZnO NPs (≥ 50 ppm), with cells exhibiting a prolonged lag phase and delayed medial FtsZ ring formation. RedoxSensor and Phag-GFP fluorescence data further show that at ZnO-NP concentrations above 50 ppm, B. subtilis reductase activity, membrane stability, and protein expression all decrease. SDS-PAGE Stains-All staining results and FT-IR data further demonstrate that ZnO NPs negatively affect exopolysaccharide production. Moreover, it was found that B. subtilis biofilm surface structures became smooth under ZnO-NP concentrations of only 5-10 ppm, with concentrations ≤ 25 ppm significantly reducing biofilm formation activity. XANES and EXAFS spectra analysis further confirmed the presence of ZnO in co-cultured B. subtilis cells, which suggests penetration of cell membranes by either ZnO NPs or toxic Zn+ ions from ionized ZnO NPs, the latter of which may be deionized to ZnO within bacterial cells. Together, these results demonstrate that ZnO NPs can affect B. subtilis viability through the inhibition of cell growth, cytosolic protein expression, and biofilm formation, and suggest that future ZnO-NP waste management strategies would do well to mitigate the potential environmental impact engendered by the disposal of these nanoparticles.

  8. ZnO Nanoparticles Affect Bacillus subtilis Cell Growth and Biofilm Formation.

    PubMed

    Hsueh, Yi-Huang; Ke, Wan-Ju; Hsieh, Chien-Te; Lin, Kuen-Song; Tzou, Dong-Ying; Chiang, Chao-Lung

    2015-01-01

    Zinc oxide nanoparticles (ZnO NPs) are an important antimicrobial additive in many industrial applications. However, mass-produced ZnO NPs are ultimately disposed of in the environment, which can threaten soil-dwelling microorganisms that play important roles in biodegradation, nutrient recycling, plant protection, and ecological balance. This study sought to understand how ZnO NPs affect Bacillus subtilis, a plant-beneficial bacterium ubiquitously found in soil. The impact of ZnO NPs on B. subtilis growth, FtsZ ring formation, cytosolic protein activity, and biofilm formation were assessed, and our results show that B. subtilis growth is inhibited by high concentrations of ZnO NPs (≥ 50 ppm), with cells exhibiting a prolonged lag phase and delayed medial FtsZ ring formation. RedoxSensor and Phag-GFP fluorescence data further show that at ZnO-NP concentrations above 50 ppm, B. subtilis reductase activity, membrane stability, and protein expression all decrease. SDS-PAGE Stains-All staining results and FT-IR data further demonstrate that ZnO NPs negatively affect exopolysaccharide production. Moreover, it was found that B. subtilis biofilm surface structures became smooth under ZnO-NP concentrations of only 5-10 ppm, with concentrations ≤ 25 ppm significantly reducing biofilm formation activity. XANES and EXAFS spectra analysis further confirmed the presence of ZnO in co-cultured B. subtilis cells, which suggests penetration of cell membranes by either ZnO NPs or toxic Zn+ ions from ionized ZnO NPs, the latter of which may be deionized to ZnO within bacterial cells. Together, these results demonstrate that ZnO NPs can affect B. subtilis viability through the inhibition of cell growth, cytosolic protein expression, and biofilm formation, and suggest that future ZnO-NP waste management strategies would do well to mitigate the potential environmental impact engendered by the disposal of these nanoparticles. PMID:26039692

  9. ZnO Nanoparticles Affect Bacillus subtilis Cell Growth and Biofilm Formation

    PubMed Central

    Hsueh, Yi-Huang; Ke, Wan-Ju; Hsieh, Chien-Te; Lin, Kuen-Song; Tzou, Dong-Ying; Chiang, Chao-Lung

    2015-01-01

    Zinc oxide nanoparticles (ZnO NPs) are an important antimicrobial additive in many industrial applications. However, mass-produced ZnO NPs are ultimately disposed of in the environment, which can threaten soil-dwelling microorganisms that play important roles in biodegradation, nutrient recycling, plant protection, and ecological balance. This study sought to understand how ZnO NPs affect Bacillus subtilis, a plant-beneficial bacterium ubiquitously found in soil. The impact of ZnO NPs on B. subtilis growth, FtsZ ring formation, cytosolic protein activity, and biofilm formation were assessed, and our results show that B. subtilis growth is inhibited by high concentrations of ZnO NPs (≥ 50 ppm), with cells exhibiting a prolonged lag phase and delayed medial FtsZ ring formation. RedoxSensor and Phag-GFP fluorescence data further show that at ZnO-NP concentrations above 50 ppm, B. subtilis reductase activity, membrane stability, and protein expression all decrease. SDS-PAGE Stains-All staining results and FT-IR data further demonstrate that ZnO NPs negatively affect exopolysaccharide production. Moreover, it was found that B. subtilis biofilm surface structures became smooth under ZnO-NP concentrations of only 5–10 ppm, with concentrations ≤ 25 ppm significantly reducing biofilm formation activity. XANES and EXAFS spectra analysis further confirmed the presence of ZnO in co-cultured B. subtilis cells, which suggests penetration of cell membranes by either ZnO NPs or toxic Zn+ ions from ionized ZnO NPs, the latter of which may be deionized to ZnO within bacterial cells. Together, these results demonstrate that ZnO NPs can affect B. subtilis viability through the inhibition of cell growth, cytosolic protein expression, and biofilm formation, and suggest that future ZnO-NP waste management strategies would do well to mitigate the potential environmental impact engendered by the disposal of these nanoparticles. PMID:26039692

  10. Toward Cell Selective Surfaces: Cell Adhesion and Proliferation on Breath Figures with Antifouling Surface Chemistry.

    PubMed

    Martínez-Campos, Enrique; Elzein, Tamara; Bejjani, Alice; García-Granda, Maria Jesús; Santos-Coquillat, Ana; Ramos, Viviana; Muñoz-Bonilla, Alexandra; Rodríguez-Hernández, Juan

    2016-03-01

    We report the preparation of microporous functional polymer surfaces that have been proven to be selective surfaces toward eukaryotic cells while maintaining antifouling properties against bacteria. The fabrication of functional porous films has been carried out by the breath figures approach that allowed us to create porous interfaces with either poly(ethylene glycol) methyl ether methacrylate (PEGMA) or 2,3,4,5,6-pentafluorostyrene (5FS). For this purpose, blends of block copolymers in a polystyrene homopolymer matrix have been employed. In contrast to the case of single functional polymer, using blends enables us to vary the chemical distribution of the functional groups inside and outside the formed pores. In particular, fluorinated groups were positioned at the edges while the hydrophilic PEGMA groups were selectively located inside the pores, as demonstrated by TOF-SIMS. More interestingly, studies of cell adhesion, growth, and proliferation on these surfaces confirmed that PEGMA functionalized interfaces are excellent candidates to selectively allow cell growth and proliferation while maintaining antifouling properties. PMID:26909529

  11. Cell surface lectin-binding glycoconjugates on marine planktonic protists.

    PubMed

    Roberts, Emily C; Zubkov, Mikhail V; Martin-Cereceda, Mercedes; Novarino, Gianfranco; Wootton, Emma C

    2006-12-01

    Carbohydrate-protein interactions appear to play an important role in the phagocytosis of microbial prey by free-living protozoa. The present study utilizes FITC-labelled plant lectins to investigate the presence and localization of cell surface glycoconjugates on live and fixed planktonic protists (Dunaliella primolecta, Oxyrrhis marina, Goniomonas amphinema, Paraphysomonas vestita and Euplotes vannus). With live flagellate preparations, lectins primarily bound to external cell surfaces, with minimal internal staining observed. In contrast, cell fixation permeabilized cell membranes, allowing lectins to bind to internal structures, such as nuclear membranes and food vacuoles, interfering with the characterization of cell surface glycoconjugates. The method developed to label cell surface sugar moieties of live planktonic protists successfully overcomes the problems associated with fixation, and thus provides a useful protocol for future studies on protistan cell surface carbohydrate characterization.

  12. Melittin interaction with sulfated cell surface sugars.

    PubMed

    Klocek, Gabriela; Seelig, Joachim

    2008-03-01

    Melittin is a 26-residue cationic peptide with cytolytic and antimicrobial properties. Studies on the action mechanism of melittin have focused almost exclusively on the membrane-perturbing properties of this peptide, investigating in detail the melittin-lipid interaction. Here, we report physical-chemical studies on an alternative mechanism by which melittin could interact with the cell membrane. As the outer surface of many cells is decorated with anionic (sulfated) glycosaminoglycans (GAGs), a strong Coulombic interaction between the two oppositely charged molecules can be envisaged. Indeed, the present study using isothermal titration calorimetry reveals a high affinity of melittin for several GAGs, that is, heparan sulfate (HS), dermatan sulfate, and heparin. The microscopic binding constant of melittin for HS is 2.4 x 10 (5) M (-1), the reaction enthalpy is Delta H melittin (0) = -1.50 kcal/mol, and the peptide-to-HS stoichiometry is approximately 11 at 10 mM Tris, 100 mM NaCl at pH 7.4 and 28 degrees C. Delta H melittin (0) is characterized by a molar heat capacity of Delta C P (0) = -227 cal mol (-1) K (-1). The large negative heat capacity change indicates that hydrophobic interactions must also be involved in the binding of melittin to HS. Circular dichroism spectroscopy demonstrates that the binding of the peptide to HS induces a conformational change to a predominantly alpha-helical structure. A model for the melittin-HS complex is presented. Melittin binding was compared with that of magainin 2 and nisin Z to HS. Magainin 2 is known for its antimicrobial properties, but it does not cause lysis of the eukaryotic cells. Nisin Z shows activity against various Gram-positive bacteria. Isothermal titration calorimetry demonstrates that magainin 2 and nisin Z do not bind to HS (5-50 degrees C, 10 mM Tris, and 100 mM NaCl at pH 7.4). PMID:18220363

  13. Vertical transmission of Zika virus targeting the radial glial cells affects cortex development of offspring mice

    PubMed Central

    Wu, Kong-Yan; Zuo, Guo-Long; Li, Xiao-Feng; Ye, Qing; Deng, Yong-Qiang; Huang, Xing-Yao; Cao, Wu-Chun; Qin, Cheng-Feng; Luo, Zhen-Ge

    2016-01-01

    The recent Zika virus (ZIKV) epidemic in Latin America coincided with a marked increase in microcephaly in newborns. However, the causal link between maternal ZIKV infection and malformation of the fetal brain has not been firmly established. Here we show a vertical transmission of ZIKV in mice and a marked effect on fetal brain development. We found that intraperitoneal (i.p.) injection of a contemporary ZIKV strain in pregnant mice led to the infection of radial glia cells (RGs) of dorsal ventricular zone of the fetuses, the primary neural progenitors responsible for cortex development, and caused a marked reduction of these cortex founder cells in the fetuses. Interestingly, the infected fetal mice exhibited a reduced cavity of lateral ventricles and a discernable decrease in surface areas of the cortex. This study thus supports the conclusion that vertically transmitted ZIKV affects fetal brain development and provides a valuable animal model for the evaluation of potential therapeutic or preventative strategies. PMID:27174054

  14. Vertical transmission of Zika virus targeting the radial glial cells affects cortex development of offspring mice.

    PubMed

    Wu, Kong-Yan; Zuo, Guo-Long; Li, Xiao-Feng; Ye, Qing; Deng, Yong-Qiang; Huang, Xing-Yao; Cao, Wu-Chun; Qin, Cheng-Feng; Luo, Zhen-Ge

    2016-06-01

    The recent Zika virus (ZIKV) epidemic in Latin America coincided with a marked increase in microcephaly in newborns. However, the causal link between maternal ZIKV infection and malformation of the fetal brain has not been firmly established. Here we show a vertical transmission of ZIKV in mice and a marked effect on fetal brain development. We found that intraperitoneal (i.p.) injection of a contemporary ZIKV strain in pregnant mice led to the infection of radial glia cells (RGs) of dorsal ventricular zone of the fetuses, the primary neural progenitors responsible for cortex development, and caused a marked reduction of these cortex founder cells in the fetuses. Interestingly, the infected fetal mice exhibited a reduced cavity of lateral ventricles and a discernable decrease in surface areas of the cortex. This study thus supports the conclusion that vertically transmitted ZIKV affects fetal brain development and provides a valuable animal model for the evaluation of potential therapeutic or preventative strategies.

  15. Vertical transmission of Zika virus targeting the radial glial cells affects cortex development of offspring mice.

    PubMed

    Wu, Kong-Yan; Zuo, Guo-Long; Li, Xiao-Feng; Ye, Qing; Deng, Yong-Qiang; Huang, Xing-Yao; Cao, Wu-Chun; Qin, Cheng-Feng; Luo, Zhen-Ge

    2016-06-01

    The recent Zika virus (ZIKV) epidemic in Latin America coincided with a marked increase in microcephaly in newborns. However, the causal link between maternal ZIKV infection and malformation of the fetal brain has not been firmly established. Here we show a vertical transmission of ZIKV in mice and a marked effect on fetal brain development. We found that intraperitoneal (i.p.) injection of a contemporary ZIKV strain in pregnant mice led to the infection of radial glia cells (RGs) of dorsal ventricular zone of the fetuses, the primary neural progenitors responsible for cortex development, and caused a marked reduction of these cortex founder cells in the fetuses. Interestingly, the infected fetal mice exhibited a reduced cavity of lateral ventricles and a discernable decrease in surface areas of the cortex. This study thus supports the conclusion that vertically transmitted ZIKV affects fetal brain development and provides a valuable animal model for the evaluation of potential therapeutic or preventative strategies. PMID:27174054

  16. Do Aging and Tactile Noise Stimulation Affect Responses to Support Surface Translations in Healthy Adults?

    PubMed Central

    Pourmoghaddam, Amir; Lee, Beom-Chan; Layne, Charles S.

    2016-01-01

    Appropriate neuromuscular responses to support surface perturbations are crucial to prevent falls, but aging-related anatomical and physiological changes affect the appropriateness and efficiency of such responses. Low-level noise application to sensory receptors has shown to be effective for postural improvement in a variety of different balance tasks, but it is unknown whether this intervention may have value for improvement of corrective postural responses. Ten healthy younger and ten healthy older adults were exposed to sudden backward translations of the support surface. Low-level noise (mechanical vibration) to the foot soles was added during random trials and temporal (response latency) and spatial characteristics (maximum center-of-pressure excursion and anterior-posterior path length) of postural responses were assessed. Mixed-model ANOVA was applied for analysis of postural response differences based on age and vibration condition. Age affected postural response characteristics, but older adults were well able to maintain balance when exposed to a postural perturbation. Low-level noise application did not affect any postural outcomes. Healthy aging affects some specific measures of postural stability, and in high-functioning older individuals, a low-level noise intervention may not be valuable. More research is needed to investigate if recurring fallers and neuropathy patients could benefit from the intervention in postural perturbation tasks. PMID:27195007

  17. Global transcriptomic analysis of model human cell lines exposed to surface-modified gold nanoparticles: the effect of surface chemistry

    NASA Astrophysics Data System (ADS)

    Grzincic, E. M.; Yang, J. A.; Drnevich, J.; Falagan-Lotsch, P.; Murphy, C. J.

    2015-01-01

    Gold nanoparticles (Au NPs) are attractive for biomedical applications not only for their remarkable physical properties, but also for the ease of which their surface chemistry can be manipulated. Many applications involve functionalization of the Au NP surface in order to improve biocompatibility, attach targeting ligands or carry drugs. However, changes in cells exposed to Au NPs of different surface chemistries have been observed, and little is known about how Au NPs and their surface coatings may impact cellular gene expression. The gene expression of two model human cell lines, human dermal fibroblasts (HDF) and prostate cancer cells (PC3) was interrogated by microarray analysis of over 14 000 human genes. The cell lines were exposed to four differently functionalized Au NPs: citrate, poly(allylamine hydrochloride) (PAH), and lipid coatings combined with alkanethiols or PAH. Gene functional annotation categories and weighted gene correlation network analysis were used in order to connect gene expression changes to common cellular functions and to elucidate expression patterns between Au NP samples. Coated Au NPs affect genes implicated in proliferation, angiogenesis, and metabolism in HDF cells, and inflammation, angiogenesis, proliferation apoptosis regulation, survival and invasion in PC3 cells. Subtle changes in surface chemistry, such as the initial net charge, lability of the ligand, and underlying layers greatly influence the degree of expression change and the type of cellular pathway affected.Gold nanoparticles (Au NPs) are attractive for biomedical applications not only for their remarkable physical properties, but also for the ease of which their surface chemistry can be manipulated. Many applications involve functionalization of the Au NP surface in order to improve biocompatibility, attach targeting ligands or carry drugs. However, changes in cells exposed to Au NPs of different surface chemistries have been observed, and little is known about how

  18. A Mass Spectrometric-Derived Cell Surface Protein Atlas

    PubMed Central

    Bausch-Fluck, Damaris; Hofmann, Andreas; Bock, Thomas; Frei, Andreas P.; Cerciello, Ferdinando; Jacobs, Andrea; Moest, Hansjoerg; Omasits, Ulrich; Gundry, Rebekah L.; Yoon, Charles; Schiess, Ralph; Schmidt, Alexander; Mirkowska, Paulina; Härtlová, Anetta; Van Eyk, Jennifer E.; Bourquin, Jean-Pierre; Aebersold, Ruedi; Boheler, Kenneth R.; Zandstra, Peter; Wollscheid, Bernd

    2015-01-01

    Cell surface proteins are major targets of biomedical research due to their utility as cellular markers and their extracellular accessibility for pharmacological intervention. However, information about the cell surface protein repertoire (the surfaceome) of individual cells is only sparsely available. Here, we applied the Cell Surface Capture (CSC) technology to 41 human and 31 mouse cell types to generate a mass-spectrometry derived Cell Surface Protein Atlas (CSPA) providing cellular surfaceome snapshots at high resolution. The CSPA is presented in form of an easy-to-navigate interactive database, a downloadable data matrix and with tools for targeted surfaceome rediscovery (http://wlab.ethz.ch/cspa). The cellular surfaceome snapshots of different cell types, including cancer cells, resulted in a combined dataset of 1492 human and 1296 mouse cell surface glycoproteins, providing experimental evidence for their cell surface expression on different cell types, including 136 G-protein coupled receptors and 75 membrane receptor tyrosine-protein kinases. Integrated analysis of the CSPA reveals that the concerted biological function of individual cell types is mainly guided by quantitative rather than qualitative surfaceome differences. The CSPA will be useful for the evaluation of drug targets, for the improved classification of cell types and for a better understanding of the surfaceome and its concerted biological functions in complex signaling microenvironments. PMID:25894527

  19. A mass spectrometric-derived cell surface protein atlas.

    PubMed

    Bausch-Fluck, Damaris; Hofmann, Andreas; Bock, Thomas; Frei, Andreas P; Cerciello, Ferdinando; Jacobs, Andrea; Moest, Hansjoerg; Omasits, Ulrich; Gundry, Rebekah L; Yoon, Charles; Schiess, Ralph; Schmidt, Alexander; Mirkowska, Paulina; Härtlová, Anetta; Van Eyk, Jennifer E; Bourquin, Jean-Pierre; Aebersold, Ruedi; Boheler, Kenneth R; Zandstra, Peter; Wollscheid, Bernd

    2015-01-01

    Cell surface proteins are major targets of biomedical research due to their utility as cellular markers and their extracellular accessibility for pharmacological intervention. However, information about the cell surface protein repertoire (the surfaceome) of individual cells is only sparsely available. Here, we applied the Cell Surface Capture (CSC) technology to 41 human and 31 mouse cell types to generate a mass-spectrometry derived Cell Surface Protein Atlas (CSPA) providing cellular surfaceome snapshots at high resolution. The CSPA is presented in form of an easy-to-navigate interactive database, a downloadable data matrix and with tools for targeted surfaceome rediscovery (http://wlab.ethz.ch/cspa). The cellular surfaceome snapshots of different cell types, including cancer cells, resulted in a combined dataset of 1492 human and 1296 mouse cell surface glycoproteins, providing experimental evidence for their cell surface expression on different cell types, including 136 G-protein coupled receptors and 75 membrane receptor tyrosine-protein kinases. Integrated analysis of the CSPA reveals that the concerted biological function of individual cell types is mainly guided by quantitative rather than qualitative surfaceome differences. The CSPA will be useful for the evaluation of drug targets, for the improved classification of cell types and for a better understanding of the surfaceome and its concerted biological functions in complex signaling microenvironments. PMID:25894527

  20. Theory of back-surface-field solar cells

    NASA Technical Reports Server (NTRS)

    Vonroos, O.

    1979-01-01

    Report describes simple concise theory of back-surface-field (BSF) solar cells (npp + junctions) based on Shockley's depletion-layer approximation and cites superiority of two-junction devices over conventional unijunction cells.

  1. The Azospirillum brasilense Che1 chemotaxis pathway controls swimming velocity, which affects transient cell-to-cell clumping.

    PubMed

    Bible, Amber; Russell, Matthew H; Alexandre, Gladys

    2012-07-01

    The Che1 chemotaxis-like pathway of Azospirillum brasilense contributes to chemotaxis and aerotaxis, and it has also been found to contribute to regulating changes in cell surface adhesive properties that affect the propensity of cells to clump and to flocculate. The exact contribution of Che1 to the control of chemotaxis and flocculation in A. brasilense remains poorly understood. Here, we show that Che1 affects reversible cell-to-cell clumping, a cellular behavior in which motile cells transiently interact by adhering to one another at their nonflagellated poles before swimming apart. Clumping precedes and is required for flocculation, and both processes appear to be independently regulated. The phenotypes of a ΔaerC receptor mutant and of mutant strains lacking cheA1, cheY1, cheB1, or cheR1 (alone or in combination) or with che1 deleted show that Che1 directly mediates changes in the flagellar swimming velocity and that this behavior directly modulates the transient nature of clumping. Our results also suggest that an additional receptor(s) and signaling pathway(s) are implicated in mediating other Che1-independent changes in clumping identified in the present study. Transient clumping precedes the transition to stable clump formation, which involves the production of specific extracellular polysaccharides (EPS); however, production of these clumping-specific EPS is not directly controlled by Che1 activity. Che1-dependent clumping may antagonize motility and prevent chemotaxis, thereby maintaining cells in a metabolically favorable niche.

  2. Primary cilia mechanics affects cell mechanosensation: A computational study.

    PubMed

    Khayyeri, Hanifeh; Barreto, Sara; Lacroix, Damien

    2015-08-21

    Primary cilia (PC) are mechanical cell structures linked to the cytoskeleton and are central to how cells sense biomechanical signals from their environment. However, it is unclear exactly how PC mechanics influences cell mechanosensation. In this study we investigate how the PC mechanical characteristics are involved in the mechanotransduction process whereby cilium deflection under fluid flow induces strains on the internal cell components that regulate the cell׳s mechanosensitive response. Our investigation employs a computational approach in which a finite element model of a cell consisting of a nucleus, cytoplasm, cortex, microtubules, actin bundles and a primary cilium was used together with a finite element representation of a flow chamber. Fluid-structure interaction analysis was performed by simulating perfusion flow of 1mm/s on the cell model. Simulations of cells with different PC mechanical characteristics, showed that the length and the stiffness of PC are responsible for the transmission of mechanical stimuli to the cytoskeleton. Fluid flow deflects the cilium, with the highest strains found at the base of the PC and in the cytoplasm. The PC deflection created further strains on the cell nucleus but did not influence microtubules and actin bundles significantly. Our results indicate that PC deflection under fluid flow stimulation transmits mechanical strain primarily to other essential organelles in the cytoplasm, such as the Golgi complex, that regulate cells' mechanoresponse. The simulations further suggest that cell mechanosensitivity can be altered by targeting PC length and rigidity.

  3. Targeting Negative Surface Charges of Cancer Cells by Multifunctional Nanoprobes

    PubMed Central

    Chen, Bingdi; Le, Wenjun; Wang, Yilong; Li, Zhuoquan; Wang, Dong; Ren, Lei; Lin, Ling; Cui, Shaobin; Hu, Jennifer J.; Hu, Yihui; Yang, Pengyuan; Ewing, Rodney C.; Shi, Donglu; Cui, Zheng

    2016-01-01

    A set of electrostatically charged, fluorescent, and superparamagnetic nanoprobes was developed for targeting cancer cells without using any molecular biomarkers. The surface electrostatic properties of the established cancer cell lines and primary normal cells were characterized by using these nanoprobes with various electrostatic signs and amplitudes. All twenty two randomly selected cancer cell lines of different organs, but not normal control cells, bound specifically to the positively charged nanoprobes. The relative surface charges of cancer cells could be quantified by the percentage of cells captured magnetically. The activities of glucose metabolism had a profound impact on the surface charge level of cancer cells. The data indicate that an elevated glycolysis in the cancer cells led to a higher level secretion of lactate. The secreted lactate anions are known to remove the positive ions, leaving behind the negative changes on the cell surfaces. This unique metabolic behavior is responsible for generating negative cancer surface charges in a perpetuating fashion. The metabolically active cancer cells are shown to a unique surface electrostatic pattern that can be used for recovering cancer cells from the circulating blood and other solutions. PMID:27570558

  4. Targeting Negative Surface Charges of Cancer Cells by Multifunctional Nanoprobes.

    PubMed

    Chen, Bingdi; Le, Wenjun; Wang, Yilong; Li, Zhuoquan; Wang, Dong; Ren, Lei; Lin, Ling; Cui, Shaobin; Hu, Jennifer J; Hu, Yihui; Yang, Pengyuan; Ewing, Rodney C; Shi, Donglu; Cui, Zheng

    2016-01-01

    A set of electrostatically charged, fluorescent, and superparamagnetic nanoprobes was developed for targeting cancer cells without using any molecular biomarkers. The surface electrostatic properties of the established cancer cell lines and primary normal cells were characterized by using these nanoprobes with various electrostatic signs and amplitudes. All twenty two randomly selected cancer cell lines of different organs, but not normal control cells, bound specifically to the positively charged nanoprobes. The relative surface charges of cancer cells could be quantified by the percentage of cells captured magnetically. The activities of glucose metabolism had a profound impact on the surface charge level of cancer cells. The data indicate that an elevated glycolysis in the cancer cells led to a higher level secretion of lactate. The secreted lactate anions are known to remove the positive ions, leaving behind the negative changes on the cell surfaces. This unique metabolic behavior is responsible for generating negative cancer surface charges in a perpetuating fashion. The metabolically active cancer cells are shown to a unique surface electrostatic pattern that can be used for recovering cancer cells from the circulating blood and other solutions. PMID:27570558

  5. Connecting the dots - III. Nightside cooling and surface friction affect climates of tidally locked terrestrial planets

    NASA Astrophysics Data System (ADS)

    Carone, L.; Keppens, R.; Decin, L.

    2016-09-01

    We investigate how nightside cooling and surface friction affect surface temperatures and large-scale circulation for tidally locked Earth-like planets. For each scenario, we vary the orbital period between Prot = 1 and 100 d and capture changes in climate states. We find drastic changes in climate states for different surface friction scenarios. For very efficient surface friction (ts,fric = 0.1 d), the simulations for short rotation periods (Prot ≤ 10 d) show predominantly standing extratropical Rossby waves. These waves lead to climate states with two high-latitude westerly jets and unperturbed meridional direct circulation. In most other scenarios, simulations with short rotation periods exhibit instead dominance by standing tropical Rossby waves. Such climate states have a single equatorial westerly jet, which disrupts direct circulation. Experiments with weak surface friction (ts,fric = 10-100 d) show decoupling between surface temperatures and circulation, which leads to strong cooling of the nightside. The experiment with ts,fric = 100 d assumes climate states with easterly flow (retrograde rotation) for medium and slow planetary rotations Prot = 12-100 d. We show that an increase of nightside cooling efficiency by one order of magnitude compared to the nominal model leads to a cooling of the nightside surface temperatures by 80-100 K. The dayside surface temperatures only drop by 25 K at the same time. The increase in thermal forcing suppresses the formation of extratropical Rossby waves on small planets (RP = 1REarth) in the short rotation period regime (Prot ≤ 10 d).

  6. Piper and Vismia species from Colombian Amazonia differentially affect cell proliferation of hepatocarcinoma cells.

    PubMed

    Lizcano, Leandro J; Siles, Maite; Trepiana, Jenifer; Hernández, M Luisa; Navarro, Rosaura; Ruiz-Larrea, M Begoña; Ruiz-Sanz, José Ignacio

    2015-01-01

    There is an increasing interest to identify plant-derived natural products with antitumor activities. In this work, we have studied the effects of aqueous leaf extracts from Amazonian Vismia and Piper species on human hepatocarcinoma cell toxicity. Results showed that, depending on the cell type, the plants displayed differential effects; thus, Vismia baccifera induced the selective killing of HepG2, while increasing cell growth of PLC-PRF and SK-HEP-1. In contrast, these two last cell lines were sensitive to the toxicity by Piper krukoffii and Piper putumayoense, while the Piperaceae did not affect HepG2 growth. All the extracts induced cytotoxicity to rat hepatoma McA-RH7777, but were innocuous (V. baccifera at concentrations < 75 µg/mL) or even protected cells from basal death (P. putumayoense) in primary cultures of rat hepatocytes. In every case, cytotoxicity was accompanied by an intracellular accumulation of reactive oxygen species (ROS). These results provide evidence for the anticancer activities of the studied plants on specific cell lines and suggest that cell killing could be mediated by ROS, thus involving mechanisms independent of the plants free radical scavenging activities. Results also support the use of these extracts of the Vismia and Piper genera with opposite effects as a model system to study the mechanisms of the antitumoral activity against different types of hepatocarcinoma. PMID:25558904

  7. How does metabolism affect cell death in cancer?

    PubMed

    Villa, Elodie; Ricci, Jean-Ehrland

    2016-07-01

    In cancer research, identifying a specificity of tumor cells compared with 'normal' proliferating cells for targeted therapy is often considered the Holy Grail for researchers and clinicians. Although diverse in origin, most cancer cells share characteristics including the ability to escape cell death mechanisms and the utilization of different methods of energy production. In the current paradigm, aerobic glycolysis is considered the central metabolic characteristic of cancer cells (Warburg effect). However, recent data indicate that cancer cells also show significant changes in other metabolic pathways. Indeed, it was recently suggested that Kreb's cycle, pentose phosphate pathway intermediates, and essential and nonessential amino acids have key roles. Renewed interest in the fact that cancer cells have to reprogram their metabolism in order to proliferate or resist treatment must take into consideration the ability of tumor cells to adapt their metabolism to the local microenvironment (low oxygen, low nutrients). This variety of metabolic sources might be either a strength, resulting in infinite possibilities for adaptation and increased ability to resist chemotherapy-induced death, or a weakness that could be targeted to kill cancer cells. Here, we discuss recent insights showing how energetic metabolism may regulate cell death and how this might be relevant for cancer treatment.

  8. Stem cell origin differently affects bone tissue engineering strategies

    PubMed Central

    Mattioli-Belmonte, Monica; Teti, Gabriella; Salvatore, Viviana; Focaroli, Stefano; Orciani, Monia; Dicarlo, Manuela; Fini, Milena; Orsini, Giovanna; Di Primio, Roberto; Falconi, Mirella

    2015-01-01

    Bone tissue engineering approaches are encouraging for the improvement of conventional bone grafting technique drawbacks. Thanks to their self-renewal and multi-lineage differentiation ability, stem cells are one of the major actors in tissue engineering approaches, and among these adult mesenchymal stem cells (MSCs) hold a great promise for regenerative medicine strategies. Bone marrow MSCs (BM-MSCs) are the first- identified and well-recognized stem cell population used in bone tissue engineering. Nevertheless, several factors hamper BM-MSC clinical application and subsequently, new stem cell sources have been investigated for these purposes. The fruitful selection and combination of tissue engineered scaffold, progenitor cells, and physiologic signaling molecules allowed the surgeon to reconstruct the missing natural tissue. On the basis of these considerations, we analyzed the capability of two different scaffolds, planned for osteochondral tissue regeneration, to modulate differentiation of adult stem cells of dissimilar local sources (i.e., periodontal ligament, maxillary periosteum) as well as adipose-derived stem cells (ASCs), in view of possible craniofacial tissue engineering strategies. We demonstrated that cells are differently committed toward the osteoblastic phenotype and therefore, taking into account their specific features, they could be intriguing cell sources in different stem cell-based bone/periodontal tissue regeneration approaches. PMID:26441682

  9. Single-cell mass spectrometry reveals small molecules that affect cell fates in the 16-cell embryo

    PubMed Central

    Onjiko, Rosemary M.; Moody, Sally A.; Nemes, Peter

    2015-01-01

    Spatial and temporal changes in molecular expression are essential to embryonic development, and their characterization is critical to understand mechanisms by which cells acquire different phenotypes. Although technological advances have made it possible to quantify expression of large molecules during embryogenesis, little information is available on metabolites, the ultimate indicator of physiological activity of the cell. Here, we demonstrate that single-cell capillary electrophoresis-electrospray ionization mass spectrometry is able to test whether differential expression of the genome translates to the domain of metabolites between single embryonic cells. Dissection of three different cell types with distinct tissue fates from 16-cell embryos of the South African clawed frog (Xenopus laevis) and microextraction of their metabolomes enabled the identification of 40 metabolites that anchored interconnected central metabolic networks. Relative quantitation revealed that several metabolites were differentially active between the cell types in the wild-type, unperturbed embryos. Altering postfertilization cytoplasmic movements that perturb dorsal development confirmed that these three cells have characteristic small-molecular activity already at cleavage stages as a result of cell type and not differences in pigmentation, yolk content, cell size, or position in the embryo. Changing the metabolite concentration caused changes in cell movements at gastrulation that also altered the tissue fates of these cells, demonstrating that the metabolome affects cell phenotypes in the embryo. PMID:25941375

  10. Molecularly engineered surfaces for cell biology: from static to dynamic surfaces.

    PubMed

    Gooding, J Justin; Parker, Stephen G; Lu, Yong; Gaus, Katharina

    2014-04-01

    Surfaces with a well-defined presentation of ligands for receptors on the cell membrane can serve as models of the extracellular matrix for studying cell adhesion or as model cell surfaces for exploring cell-cell contacts. Because such surfaces can provide exquisite control over, for example, the density of these ligands or when the ligands are presented to the cell, they provide a very precise strategy for understanding the mechanisms by which cells respond to external adhesive cues. In the present feature article, we present an overview of the basic biology of cell adhesion before discussing surfaces that have a static presentation of immobile ligands. We outline the biological information that such surfaces have given us, before progressing to recently developed switchable surfaces and surfaces that mimic the lipid bilayer, having adhesive ligands that can move around the membrane and be remodeled by the cell. Finally, the feature article closes with some of the biological information that these new types of surfaces could provide.

  11. Genetic background affects susceptibility to tumoral stem cell reprogramming

    PubMed Central

    García-Ramírez, Idoia; Ruiz-Roca, Lucía; Martín-Lorenzo, Alberto; Blanco, Óscar; García-Cenador, María Begoña; García-Criado, Francisco Javier; Vicente-Dueñas, Carolina; Sánchez-García, Isidro

    2013-01-01

    The latest studies of the interactions between oncogenes and its target cell have shown that certain oncogenes may act as passengers to reprogram tissue-specific stem/progenitor cell into a malignant cancer stem cell state. In this study, we show that the genetic background influences this tumoral stem cell reprogramming capacity of the oncogenes using as a model the Sca1-BCRABLp210 mice, where the type of tumor they develop, chronic myeloid leukemia (CML), is a function of tumoral stem cell reprogramming. Sca1-BCRABLp210 mice containing FVB genetic components were significantly more resistant to CML. However, pure Sca1-BCRABLp210 FVB mice developed thymomas that were not seen in the Sca1-BCRABLp210 mice into the B6 background. Collectively, our results demonstrate for the first time that tumoral stem cell reprogramming fate is subject to polymorphic genetic control. PMID:23839033

  12. Harvesting Technique Affects Adipose-Derived Stem Cell Yield

    PubMed Central

    Iyyanki, Tejaswi; Hubenak, Justin; Liu, Jun; Chang, Edward I.; Beahm, Elisabeth K.; Zhang, Qixu

    2015-01-01

    Background The success of an autologous fat graft depends in part on its total stromal vascular fraction (SVF) and adipose-derived stem cells (ASCs). However, variations in the yields of ASCs and SVF cells as a result of different harvesting techniques and donor sites are poorly understood. Objective To investigate the effects of adipose tissue harvesting technique and donor site on the yield of ASCs and SVF cells. Methods Subcutaneous fat tissues from the abdomen, flank, or axilla were harvested from patients of various ages by mechanical liposuction, direct surgical excision, or Coleman's technique with or without centrifugation. Cells were isolated and then analyzed with flow cytometry to determine the yields of total SVF cells and ASCs (CD11b−, CD45−, CD34+, CD90+, D7-FIB+). Differences in ASC and total SVF yields were assessed with one-way analysis of variance. Differentiation experiments were performed to confirm the multilineage potential of cultured SVF cells. Results Compared with Coleman's technique without centrifugation, direct excision yielded significantly more ASCs (P < .001) and total SVF cells (P = .007); liposuction yielded significantly fewer ASCs (P < .001) and total SVF cells (P < .05); and Coleman's technique with centrifugation yielded significantly more total SVF cells (P < .005), but not ASCs. The total number of SVF cells in fat harvested from the abdomen was significantly larger than the number in fat harvested from the flank or axilla (P < .05). Cultured SVF cells differentiated to adipocytes, osteocytes, and chondrocytes. Conclusions Adipose tissue harvested from the abdomen through direct excision or Coleman's technique with centrifugation was found to yield the most SVF cells and ASCs. PMID:25791999

  13. Different Culture Media Affect Proliferation, Surface Epitope Expression, and Differentiation of Ovine MSC.

    PubMed

    Adamzyk, Carina; Emonds, Tanja; Falkenstein, Julia; Tolba, René; Jahnen-Dechent, Wilhelm; Lethaus, Bernd; Neuss, Sabine

    2013-01-01

    Orthopedic implants including engineered bone tissue are commonly tested in sheep. To avoid rejection of heterologous or xenogeneic cells, autologous cells are preferably used, that is, ovine mesenchymal stem cells (oMSC). Unlike human MSC, ovine MSC are not well studied regarding isolation, expansion, and characterization. Here we investigated the impact of culture media composition on growth characteristics, differentiation, and surface antigen expression of oMSC. The culture media varied in fetal calf serum (FCS) content and in the addition of supplements and/or additional epidermal growth factor (EGF). We found that FCS strongly influenced oMSC proliferation and that specific combinations of supplemental factors (MCDB-201, ITS-plus, dexamethasone, and L-ascorbic acid) determined the expression of surface epitopes. We compared two published protocols for oMSC differentiation towards the osteogenic, adipogenic, and chondrogenic fate and found (i) considerable donor to donor variations, (ii) protocol-dependent variations, and (iii) variations resulting from the preculture medium composition. Our results indicate that the isolation and culture of oMSC in different growth media are highly variable regarding oMSC phenotype and behaviour. Furthermore, variations from donor to donor critically influence growth rate, surface marker expression, and differentiation. PMID:24228035

  14. Different Culture Media Affect Proliferation, Surface Epitope Expression, and Differentiation of Ovine MSC.

    PubMed

    Adamzyk, Carina; Emonds, Tanja; Falkenstein, Julia; Tolba, René; Jahnen-Dechent, Wilhelm; Lethaus, Bernd; Neuss, Sabine

    2013-01-01

    Orthopedic implants including engineered bone tissue are commonly tested in sheep. To avoid rejection of heterologous or xenogeneic cells, autologous cells are preferably used, that is, ovine mesenchymal stem cells (oMSC). Unlike human MSC, ovine MSC are not well studied regarding isolation, expansion, and characterization. Here we investigated the impact of culture media composition on growth characteristics, differentiation, and surface antigen expression of oMSC. The culture media varied in fetal calf serum (FCS) content and in the addition of supplements and/or additional epidermal growth factor (EGF). We found that FCS strongly influenced oMSC proliferation and that specific combinations of supplemental factors (MCDB-201, ITS-plus, dexamethasone, and L-ascorbic acid) determined the expression of surface epitopes. We compared two published protocols for oMSC differentiation towards the osteogenic, adipogenic, and chondrogenic fate and found (i) considerable donor to donor variations, (ii) protocol-dependent variations, and (iii) variations resulting from the preculture medium composition. Our results indicate that the isolation and culture of oMSC in different growth media are highly variable regarding oMSC phenotype and behaviour. Furthermore, variations from donor to donor critically influence growth rate, surface marker expression, and differentiation.

  15. Surface topography of granulosa cells accompanied by fragmented oocytes.

    PubMed

    Shinohara, H; Noda, M; Kima, M; Matsuda, T

    1983-07-15

    Scanning electron microscopy of granulosa cells (GC) and granulosa cell-like structures (GCLS) revealed that both had lacy foldings, or plicae, on the surface and were identical. The plicae did not always cover the entire surface of GC or GCLS. Both structures were interconnected by multivalent processes.

  16. Cell Surface-based Sensing with Metallic Nanoparticles

    PubMed Central

    Jiang, Ziwen; Rotello, Vincent M.

    2015-01-01

    Metallic nanoparticles provide versatile scaffolds for biosensing applications. In this review, we focus on the use of metallic nanoparticles for cell surface sensings. Examples of the use of both specific recognition and array-based “chemical nose” approaches to cell surface sensing will be discussed. PMID:25853985

  17. Dynamics of high Weber number drops impacting on hydrophobic surfaces with closed micro-cells.

    PubMed

    Zhang, Rui; Hao, Pengfei; Zhang, Xiwen; He, Feng

    2016-06-29

    The impact dynamics and bouncing performance of high Weber number drops on hydrophobic surfaces with open and closed micro-cells are investigated. Central wetted rings are observed on both closed-cell and open-cell surfaces under high Weber number collisions, which are proposed to constitute the key element affecting the bouncing behaviour. It is found that the drops rebound on closed-cell surfaces where the central area is in the "hybrid wetting state" at high Weber numbers, while the drops adhere to the open-cell surfaces where the central region is in the Wenzel state. A theoretical model is developed to explain this interesting phenomenon, in which the liquid cannot reach the bottom of the closed-cell hydrophobic surfaces since the air stored in micro-cavities prevents the sliding motion of the liquid film and functions as a "gas spring" lifting the liquid lamella. This indicates that the hydrophobic surface with simple micro cavities can maintain the water-repellent characteristics under drop impacts at high Weber numbers. These findings are expected to be crucial to a fundamental understanding of the rapid collisions between drops and micro-structured surfaces, as well as a valuable strategy to guide the fabrication of novel super water-repellant and anti-icing surfaces. PMID:27306824

  18. Brucella abortus Choloylglycine Hydrolase Affects Cell Envelope Composition and Host Cell Internalization

    PubMed Central

    Marchesini, María Inés; Connolly, Joseph; Delpino, María Victoria; Baldi, Pablo C.; Mujer, Cesar V.; DelVecchio, Vito G.; Comerci, Diego J.

    2011-01-01

    Choloylglycine hydrolase (CGH, E.C. 3.5.1.24) is a conjugated bile salt hydrolase that catalyses the hydrolysis of the amide bond in conjugated bile acids. Bile salt hydrolases are expressed by gastrointestinal bacteria, and they presumably decrease the toxicity of host's conjugated bile salts. Brucella species are the causative agents of brucellosis, a disease affecting livestock and humans. CGH confers Brucella the ability to deconjugate and resist the antimicrobial action of bile salts, contributing to the establishment of a successful infection through the oral route in mice. Additionally, cgh-deletion mutant was also attenuated in intraperitoneally inoculated mice, which suggests that CGH may play a role during systemic infection other than hydrolyzing conjugated bile acids. To understand the role CGH plays in B. abortus virulence, we infected phagocytic and epithelial cells with a cgh-deletion mutant (Δcgh) and found that it is defective in the internalization process. This defect along with the increased resistance of Δcgh to the antimicrobial action of polymyxin B, prompted an analysis of the cell envelope of this mutant. Two-dimensional electrophoretic profiles of Δcgh cell envelope-associated proteins showed an altered expression of Omp2b and different members of the Omp25/31 family. These results were confirmed by Western blot analysis with monoclonal antibodies. Altogether, the results indicate that Brucella CGH not only participates in deconjugation of bile salts but also affects overall membrane composition and host cell internalization. PMID:22174816

  19. Brucella abortus choloylglycine hydrolase affects cell envelope composition and host cell internalization.

    PubMed

    Marchesini, María Inés; Connolly, Joseph; Delpino, María Victoria; Baldi, Pablo C; Mujer, Cesar V; DelVecchio, Vito G; Comerci, Diego J

    2011-01-01

    Choloylglycine hydrolase (CGH, E.C. 3.5.1.24) is a conjugated bile salt hydrolase that catalyses the hydrolysis of the amide bond in conjugated bile acids. Bile salt hydrolases are expressed by gastrointestinal bacteria, and they presumably decrease the toxicity of host's conjugated bile salts. Brucella species are the causative agents of brucellosis, a disease affecting livestock and humans. CGH confers Brucella the ability to deconjugate and resist the antimicrobial action of bile salts, contributing to the establishment of a successful infection through the oral route in mice. Additionally, cgh-deletion mutant was also attenuated in intraperitoneally inoculated mice, which suggests that CGH may play a role during systemic infection other than hydrolyzing conjugated bile acids. To understand the role CGH plays in B. abortus virulence, we infected phagocytic and epithelial cells with a cgh-deletion mutant (Δcgh) and found that it is defective in the internalization process. This defect along with the increased resistance of Δcgh to the antimicrobial action of polymyxin B, prompted an analysis of the cell envelope of this mutant. Two-dimensional electrophoretic profiles of Δcgh cell envelope-associated proteins showed an altered expression of Omp2b and different members of the Omp25/31 family. These results were confirmed by Western blot analysis with monoclonal antibodies. Altogether, the results indicate that Brucella CGH not only participates in deconjugation of bile salts but also affects overall membrane composition and host cell internalization.

  20. Investigation of back surface fields effect on bifacial solar cells

    NASA Astrophysics Data System (ADS)

    Sepeai, Suhaila; Sulaiman, M. Y.; Sopian, Kamaruzzaman; Zaidi, Saleem H.

    2012-11-01

    A bifacial solar cell, in contrast with a conventional monofacial solar cell, produces photo-generated current from both front and back sides. Bifacial solar cell is an attractive candidate for enhancing photovoltaic (PV) market competitiveness as well as supporting the current efforts to increase efficiency and lower material costs. This paper reports on the fabrication of bifacial solar cells using phosphorus-oxytrichloride (POCl3) emitter formation on p-type, nanotextured silicon (Si) wafer. Backside surface field was formed through Al-diffusion using conventional screen-printing process. Bifacial solar cells with a structure of n+pp+ with and without back surface field (BSF) were fabricated in which silicon nitride (SiN) anti reflection and passivation films were coated on both sides, followed by screen printing of Argentum (Ag) and Argentum/Aluminum (Ag/Al) on front and back contacts, respectively. Bifacial solar cells without BSF exhibited open circuit voltage (VOC) of 535 mV for front and 480 mV for back surface. With Al-alloyed BSF bifacial solar cells, the VOC improved to 580 mV for the front surface and 560 mV for the back surface. Simulation of bifacial solar cells using PC1D and AFORS software demonstrated good agreement with experimental results. Simulations showed that best bifacial solar cells are achieved through a combination of high lifetime wafer, low recombination back surface field, reduced contact resistance, and superior surface passivation.

  1. Transcriptional modulator ZBED6 affects cell cycle and growth of human colorectal cancer cells.

    PubMed

    Akhtar Ali, Muhammad; Younis, Shady; Wallerman, Ola; Gupta, Rajesh; Andersson, Leif; Sjöblom, Tobias

    2015-06-23

    The transcription factor ZBED6 (zinc finger, BED-type containing 6) is a repressor of IGF2 whose action impacts development, cell proliferation, and growth in placental mammals. In human colorectal cancers, IGF2 overexpression is mutually exclusive with somatic mutations in PI3K signaling components, providing genetic evidence for a role in the PI3K pathway. To understand the role of ZBED6 in tumorigenesis, we engineered and validated somatic cell ZBED6 knock-outs in the human colorectal cancer cell lines RKO and HCT116. Ablation of ZBED6 affected the cell cycle and led to increased growth rate in RKO cells but reduced growth in HCT116 cells. This striking difference was reflected in the transcriptome analyses, which revealed enrichment of cell-cycle-related processes among differentially expressed genes in both cell lines, but the direction of change often differed between the cell lines. ChIP sequencing analyses displayed enrichment of ZBED6 binding at genes up-regulated in ZBED6-knockout clones, consistent with the view that ZBED6 modulates gene expression primarily by repressing transcription. Ten differentially expressed genes were identified as putative direct gene targets, and their down-regulation by ZBED6 was validated experimentally. Eight of these genes were linked to the Wnt, Hippo, TGF-β, EGF receptor, or PI3K pathways, all involved in colorectal cancer development. The results of this study show that the effect of ZBED6 on tumor development depends on the genetic background and the transcriptional state of its target genes.

  2. Chemistry-enabled methods for the visualization of cell-surface glycoproteins in Metazoans.

    PubMed

    Chuh, Kelly N; Pratt, Matthew R

    2015-10-01

    The majority of cell-surface and secreted proteins are glycosylated, which can directly affect their macromolecular interactions, stability, and localization. Investigating these effects is critical to developing a complete understanding of the role of glycoproteins in fundamental biology and human disease. The development of selective and unique chemical reactions have revolutionized the visualization, identification, and characterization of glycoproteins. Here, we review the chemical methods that have been created to enable the visualization of the major types of cell-surface glycoproteins in living systems, from mammalian cells to whole animals.

  3. Mutations in Coliphage P1 Affecting Host Cell Lysis

    PubMed Central

    Walker, Jean Tweedy; Walker, Donald H.

    1980-01-01

    A total of 103 amber mutants of coliphage P1 were tested for lysis of nonpermissive cells. Of these, 83 caused cell lysis at the normal lysis time and have defects in particle morphogenesis. Five amber mutants, with mutations in the same gene (gene 2), caused premature lysis and may have a defect in a lysis regulator. Fifteen amber mutants were unable to cause cell lysis. Artificially lysed cells infected with five of these mutants produced viable phage particles, and phage particles were seen in thin sections of unlysed, infected cells. However, phage production by these mutants was not continued after the normal lysis time. We conclude that the defect of these five mutants is in a lysis function. The five mutations were found to be in the same gene (designated gene 17). The remaining 10 amber mutants, whose mutations were found to be in the same gene (gene 10), were also unable to cause cell lysis. They differed from those in gene 17 in that no viable phage particles were produced from artificially lysed cells, and no phage particles were seen in thin sections of unlysed, infected cells. We conclude that the gene 10 mutants cannot synthesize late proteins, and it is possible that gene 10 may code for a regulator of late gene expression for P1. Images PMID:16789200

  4. Glycosaminoglycans affect heparanase location in CHO cell lines.

    PubMed

    Piva, Maria B R; Suarez, Eloah R; Melo, Carina M; Cavalheiro, Renan P; Nader, Helena B; Pinhal, Maria A S

    2015-09-01

    Glycosaminoglycans (GAG) play a ubiquitous role in tissues and cells. In eukaryotic cells, heparan sulfate (HS) is initially degraded by an endo-β-glucuronidase called heparanase-1 (HPSE). HS oligosaccharides generated by the action of HPSE intensify the activity of signaling molecules, activating inflammatory response, tumor metastasis, and angiogenesis. The aim of the present study was to understand if sulfated GAG could modulate HPSE, since the mechanisms that regulate HPSE have not been completely defined. CHO-K1 cells were treated with 4-methylumbelliferone (4-MU) and sodium chlorate, to promote total inhibition of GAG synthesis, and reduce the sulfation pattern, respectively. The GAG profile of the wild CHO-K1 cells and CHO-745, deficient in xylosyltransferase, was determined after [(35)S]-sulfate labeling. HPSE expression was determined via real-time quantitative polymerase chain reaction. Total ablation of GAG with 4-MU in CHO-K1 inhibited HPSE expression, while the lack of sulfation had no effect. Interestingly, 4-MU had no effect in CHO-745 cells for these assays. In addition, a different enzyme location was observed in CHO-K1 wild-type cells, which presents HPSE mainly in the extracellular matrix, in comparison with the CHO-745 mutant cells, which is found in the cytoplasm. In view of our results, we can conclude that GAG are essential modulators of HPSE expression and location. Therefore, GAG profile could impact cell behavior mediated by the regulation of HPSE.

  5. Cell culture density affects the proliferation activity of human adipose tissue stem cells.

    PubMed

    Kim, Dae Seong; Lee, Myoung Woo; Ko, Young Jong; Chun, Yong Hoon; Kim, Hyung Joon; Sung, Ki Woong; Koo, Hong Hoe; Yoo, Keon Hee

    2016-01-01

    In this study, we investigated the effect of cell density on the proliferation activity of human mesenchymal stem cells (MSCs) derived from adipose tissue (AT-MSCs) over time in culture. Passage #4 (P4) and #12 (P12) AT-MSCs from two donors were plated at a density of 200 (culture condition 1, CC1) or 5000 (culture condition 2, CC2) cells cm(-2) . After 7 days of incubation, P4 and P12 AT-MSCs cultured in CC1 were thin and spindle-shaped, whereas those cultured in CC2 had extensive cell-to-cell contacts and an expanded cell volume. In addition, P4 and P12 AT-MSCs in CC1 divided more than three times, while those in CC2 divided less than once on average. Flow cytometric analysis using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester dye showed that the fluorescence intensity of AT-MSCs was lower in CC1 than in CC2. Furthermore, expression of proliferation-associated genes, such as CDC45L, CDC20A and KIF20A, in P4 AT-MSCs was higher in CC1 than in CC2, and this difference was also observed in P12 AT-MSCs. These data demonstrated that cell culture density affects the proliferation activity of MSCs, suggesting that it is feasible to design a strategy to prepare suitable MSCs using specific culture conditions.

  6. Modulation of cell-surface antigens of a murine neuroblastoma.

    PubMed

    Akeson, R; Herschman, H R

    1974-01-01

    Antisera were produced in rabbits to morphologically differentiated cells from the C1300 murine neuroblastoma (i.e., cells in which process formation was induced by maintenance on serum-free medium for 5 days). These antisera reacted more strongly in the complement fixation reaction with such "differentiated" cells than with "undifferentiated" (nonprocess-bearing) neuroblastoma cells. Adsorption of the antisera with undifferentiated cells removed the reactivity to cells without processes, while the reactivity with serum-free cells which possess processes was retained. Indirect immunofluorescence studies confirmed the results obtained by complement fixation and demonstrated that antibodies to the surface antigens of process-bearing cells could be adsorbed by particulate preparations from brain but not liver, spleen, or kidney. This is the first description of neural-associated cell-surface changes that correlate with the morphological differentiation in culture of neuroblastoma cells.

  7. Stem cell behavior on tailored porous oxide surface coatings.

    PubMed

    Lavenus, Sandrine; Poxson, David J; Ogievetsky, Nika; Dordick, Jonathan S; Siegel, Richard W

    2015-07-01

    Nanoscale surface topographies are known to have a profound influence on cell behavior, including cell guidance, migration, morphology, proliferation, and differentiation. In this study, we have observed the behavior of human mesenchymal stem cells cultured on a range of tailored porous SiO2 and TiO2 nanostructured surface coatings fabricated via glancing angle electron-beam deposition. By controlling the physical vapor deposition angle during fabrication, we could control systematically the deposited coating porosity, along with associated topographic features. Immunocytochemistry and image analysis quantitatively revealed the number of adherent cells, as well as their basic cellular morphology, on these surfaces. Signaling pathway studies showed that even with subtle changes in nanoscale surface structures, the behavior of mesenchymal stem cells was strongly influenced by the precise surface structures of these porous coatings.

  8. Effect of sterilization and water rinsing on cell adhesion to titanium surfaces

    NASA Astrophysics Data System (ADS)

    Hirano, Mitsuhiro; Kozuka, Taro; Asano, Yuta; Kakuchi, Yuko; Arai, Hirofumi; Ohtsu, Naofumi

    2014-08-01

    In this study, the effects of sterilization and water rinsing on cell adhesion to titanium (Ti) surfaces were investigated. Ti substrates were treated using autoclave, dry-heating, and 70% ethanol. Thereafter, some of the substrates were rinsed with sterilized ultrapure water. Osteoblast-like MC3T3-E1 cells were seeded on the Ti surfaces and the numbers of adhered cells were counted after cultivation for 24 h. The number of cells adhered to ethanol-treated plates was lower than that on autoclave- and dry-heat-sterilized Ti substrates. However, interestingly, the cell adhesion performance on the ethanol-treated substrates was superior compared to that of the other substrates, after rinsing with ultrapure water. To investigate the origin of these differences, the chemical state of the treated surfaces was analyzed by X-ray photoelectron spectroscopy. We found a clear correlation between the number of adhered cells and the concentration of hydroxide groups (OH-) on the surface, thus indicating that a change in OH- concentration affects the cell adhesion performance on Ti substrates. Since the sterilization and subsequent water rinsing affect the cell adhesion on Ti substrates, we suggest that the sterilization methods should be unified to correctly evaluate the cytocompatibility of metallic materials.

  9. Advances in cell surface glycoengineering reveal biological function.

    PubMed

    Nischan, Nicole; Kohler, Jennifer J

    2016-08-01

    Cell surface glycans are critical mediators of cell-cell, cell-ligand, and cell-pathogen interactions. By controlling the set of glycans displayed on the surface of a cell, it is possible to gain insight into the biological functions of glycans. Moreover, control of glycan expression can be used to direct cellular behavior. While genetic approaches to manipulate glycosyltransferase gene expression are available, their utility in glycan engineering has limitations due to the combinatorial nature of glycan biosynthesis and the functional redundancy of glycosyltransferase genes. Biochemical and chemical strategies offer valuable complements to these genetic approaches, notably by enabling introduction of unnatural functionalities, such as fluorophores, into cell surface glycans. Here, we describe some of the most recent developments in glycoengineering of cell surfaces, with an emphasis on strategies that employ novel chemical reagents. We highlight key examples of how these advances in cell surface glycan engineering enable study of cell surface glycans and their function. Exciting new technologies include synthetic lipid-glycans, new chemical reporters for metabolic oligosaccharide engineering to allow tandem and in vivo labeling of glycans, improved chemical and enzymatic methods for glycoproteomics, and metabolic glycosyltransferase inhibitors. Many chemical and biochemical reagents for glycan engineering are commercially available, facilitating their adoption by the biological community.

  10. Intracellular transport and cell surface delivery of the neural cell adhesion molecule (NCAM).

    PubMed

    Leshchyns'ka, Iryna; Sytnyk, Vladimir

    2015-01-01

    The neural cell adhesion molecule (NCAM) regulates differentiation and functioning of neurons by accumulating at the cell surface where it mediates the interactions of neurons with the extracellular environment. NCAM also induces a number of intracellular signaling cascades, which coordinate interactions at the cell surface with intracellular processes including changes in gene expression, transport and cytoskeleton remodeling. Since NCAM functions at the cell surface, its transport and delivery to the cell surface play a critical role. Here, we review recent advances in our understanding of the molecular mechanisms of the intracellular transport and cell surface delivery of NCAM. We also discuss the data suggesting a possibility of cross talk between activation of NCAM at the cell surface and the intracellular transport and cell surface delivery of NCAM.

  11. The Use of Yeast Surface Display in Biofuel Cells.

    PubMed

    Szczupak, Alon; Alfonta, Lital

    2015-01-01

    Biofuel cells are electrochemical devices which convert chemical energy to electricity using biochemical pathways and redox enzymes. In enzymatic fuel cells purified redox enzymes catalyze the reactions in the anode and cathode compartments whereas in microbial fuel cells (MFCs) the entire metabolism of the microorganisms is exploited. Here, a hybrid biofuel cell concept is presented, which is based on yeast surface display (YSD) of redox enzymes to catalyze the different cell reactions. PMID:26060081

  12. Attachment of human primary osteoblast cells to modified polyethylene surfaces.

    PubMed

    Poulsson, Alexandra H C; Mitchell, Stephen A; Davidson, Marcus R; Johnstone, Alan J; Emmison, Neil; Bradley, Robert H

    2009-04-01

    Ultra-high-molecular-weight polyethylene (UHMWPE) has a long history of use in medical devices, primarily for articulating surfaces due to its inherent low surface energy which limits tissue integration. To widen the applications of UHMWPE, the surface energy can be increased. The increase in surface energy would improve the adsorption of proteins and attachment of cells to allow tissue integration, thereby allowing UHMWPE to potentially be used for a wider range of implants. The attachment and function of human primary osteoblast-like (HOB) cells to surfaces of UHMWPE with various levels of incorporated surface oxygen have been investigated. The surface modification of the UHMWPE was produced by exposure to a UV/ozone treatment. The resulting surface chemistry was studied using X-ray photoelectron spectroscopy (XPS), and the topography and surface structure were probed by atomic force microscopy (AFM) and scanning electron microscopy (SEM), which showed an increase in surface oxygen from 11 to 26 atom % with no significant change to the surface topography. The absolute root mean square roughness of both untreated and UV/ozone-treated surfaces was within 350-450 nm, and the water contact angles decreased with increasing oxygen incorporation, i.e., showing an increase in surface hydrophilicity. Cell attachment and functionality were assessed over a 21 day period for each cell-surface combination studied; these were performed using SEM and the alamarBlue assay to study cell attachment and proliferation and energy-dispersive X-ray (EDX) analysis to confirm extracellular mineral deposits, and total protein assay to examine the intra- and extracellular protein expressed by the cells. HOB cells cultured for 21 days on the modified UHMWPE surfaces with 19 and 26 atom % oxygen incorporated showed significantly higher cell densities compared to cells cultured on tissue culture polystyrene (TCPS) from day 3 onward. This indicated that the cells attached and proliferated more

  13. Near-surface physics during convection affecting air-water gas transfer

    NASA Astrophysics Data System (ADS)

    Fredriksson, S. T.; Arneborg, L.; Nilsson, H.; Handler, R. A.

    2016-05-01

    The gas flux at the water surface is affected by physical processes including turbulence from wind shear, microscale wave breaking, large-scale breaking, and convection due to heat loss at the surface. The main route in the parameterizations of the gas flux has been to use the wind speed as a proxy for the gas flux velocity, indirectly taking into account the dependency of the wind shear and the wave processes. The interest in the contributions from convection processes has increased as the gas flux from inland waters (with typically lower wind and sheltered conditions) now is believed to play a substantial role in the air-water gas flux budget. The gas flux is enhanced by convection through the mixing of the mixed layer as well as by decreasing the diffusive boundary layer thickness. The direct numerical simulations performed in this study are shown to be a valuable tool to enhance the understanding of this flow configuration often present in nature.

  14. DIRECT COMPARISON OF KINETIC AND LOCAL EQUILIBRIUM FORMULATIONS FOR SOLUTE TRANSPORT AFFECTED BY SURFACE REACTIONS.

    USGS Publications Warehouse

    Bahr, Jean M.; Rubin, Jacob

    1987-01-01

    Modeling transport of reacting solutes in porous media often requires a choice between models based on the local equilibrium assumption (LEA) and models involving reaction kinetics. Direct comparison of the mathematical formulations for these two types of transport models can aid in this choice. For cases of transport affected by surface reaction, such a comparison is made possible by a new derivation procedure. This procedure yields a kinetics-based formulation that is the sum of the LEA formulation and one or more kinetically influenced terms. The dimensionless form of the new kinetics-based formulation facilitates identification of critical parameter groupings which control the approach to transport behavior consistent with LEA model predictions. Results of numerical experiments demonstrate that criteria for LEA applicability can be expressed conveniently in terms of these parameter groupings. The derivation procedure is demonstrated for examples of surface reactions including first-order reversible sorption, Langmuir-type kinetics and binary, homovalent ion exchange.

  15. Analysis of the cell surface expression of cytokine receptors using the surface protein biotinylation method.

    PubMed

    Pavel, Mahmud Arif; Lam, Clarissa; Kashyap, Parul; Salehi-Najafabadi, Zahra; Singh, Gurpreet; Yu, Yong

    2014-01-01

    Cytokines are pleiotropic, low-molecular-weight proteins that regulate the immune responses to infection and inflammation. They stimulate the immune responses by binding to cytokine receptors on the cell plasma membrane. Thus, knowledge of the expression level of particular cytokine receptors on cell surface is crucial for understanding the cytokine function and regulation. One of the techniques to explore the membrane embedded cytokine receptors is cell surface biotinylation. Biotinylated surface proteins can be rapidly purified through the strong interaction between biotin and streptavidin. Here, we describe the procedure for surface biotinylation and purification of biotinylated cytokine receptors for further downstream analysis. PMID:24908305

  16. Analysis of the cell surface expression of cytokine receptors using the surface protein biotinylation method.

    PubMed

    Pavel, Mahmud Arif; Lam, Clarissa; Kashyap, Parul; Salehi-Najafabadi, Zahra; Singh, Gurpreet; Yu, Yong

    2014-01-01

    Cytokines are pleiotropic, low-molecular-weight proteins that regulate the immune responses to infection and inflammation. They stimulate the immune responses by binding to cytokine receptors on the cell plasma membrane. Thus, knowledge of the expression level of particular cytokine receptors on cell surface is crucial for understanding the cytokine function and regulation. One of the techniques to explore the membrane embedded cytokine receptors is cell surface biotinylation. Biotinylated surface proteins can be rapidly purified through the strong interaction between biotin and streptavidin. Here, we describe the procedure for surface biotinylation and purification of biotinylated cytokine receptors for further downstream analysis.

  17. Inhibition of cyclooxygenase (COX)-2 affects endothelial progenitor cell proliferation

    SciTech Connect

    Colleselli, Daniela; Bijuklic, Klaudija; Mosheimer, Birgit A.; Kaehler, Christian M. . E-mail: C.M.Kaehler@uibk.ac.at

    2006-09-10

    Growing evidence indicates that inducible cyclooxygenase-2 (COX-2) is involved in the pathogenesis of inflammatory disorders and various types of cancer. Endothelial progenitor cells recruited from the bone marrow have been shown to be involved in the formation of new vessels in malignancies and discussed for being a key point in tumour progression and metastasis. However, until now, nothing is known about an interaction between COX and endothelial progenitor cells (EPC). Expression of COX-1 and COX-2 was detected by semiquantitative RT-PCR and Western blot. Proliferation kinetics, cell cycle distribution and rate of apoptosis were analysed by MTT test and FACS analysis. Further analyses revealed an implication of Akt phosphorylation and caspase-3 activation. Both COX-1 and COX-2 expression can be found in bone-marrow-derived endothelial progenitor cells in vitro. COX-2 inhibition leads to a significant reduction in proliferation of endothelial progenitor cells by an increase in apoptosis and cell cycle arrest. COX-2 inhibition leads further to an increased cleavage of caspase-3 protein and inversely to inhibition of Akt activation. Highly proliferating endothelial progenitor cells can be targeted by selective COX-2 inhibition in vitro. These results indicate that upcoming therapy strategies in cancer patients targeting COX-2 may be effective in inhibiting tumour vasculogenesis as well as angiogenic processes.

  18. Mesenchymal Stromal Cells Affect Disease Outcomes via Macrophage Polarization

    PubMed Central

    Zheng, Guoping; Ge, Menghua; Qiu, Guanguan; Shu, Qiang; Xu, Jianguo

    2015-01-01

    Mesenchymal stromal cells (MSCs) are multipotent and self-renewable cells that reside in almost all postnatal tissues. In recent years, many studies have reported the effect of MSCs on the innate and adaptive immune systems. MSCs regulate the proliferation, activation, and effector function of T lymphocytes, professional antigen presenting cells (dendritic cells, macrophages, and B lymphocytes), and NK cells via direct cell-to-cell contact or production of soluble factors including indoleamine 2,3-dioxygenase, prostaglandin E2, tumor necrosis factor-α stimulated gene/protein 6, nitric oxide, and IL-10. MSCs are also able to reprogram macrophages from a proinflammatory M1 phenotype toward an anti-inflammatory M2 phenotype capable of regulating immune response. Because of their capacity for differentiation and immunomodulation, MSCs have been used in many preclinical and clinical studies as possible new therapeutic agents for the treatment of autoimmune, degenerative, and inflammatory diseases. In this review, we discuss the central role of MSCs in macrophage polarization and outcomes of diseases such as wound healing, brain/spinal cord injuries, and diseases of heart, lung, and kidney in animal models. PMID:26257791

  19. How will surface treatments affect the translucency of porcelain laminate veneers?

    PubMed Central

    Turgut, Sedanur; Ayaz, Elif Aydogan; Korkmaz, Fatih Mehmet; Ulusoy, Kıvanç Utku; Bagis, Yildirim Hakan

    2014-01-01

    PURPOSE The purpose of this study was to evaluate whether surface treatments affect the translucency of laminate veneers with different shades and thicknesses. MATERIALS AND METHODS A total of 224 disc-shaped ceramic veneers were prepared from A1, A3, HT (High Translucent) and HO (High Opaque) shades of IPS e.max Press (Ivoclar Vivadent) with 0.5 mm and 1.0 mm thicknesses. The ceramics were divided into four groups for surface treatments. Group C: no surface treatments; Group HF: etched with hydrofluoric acid; Group SB: sandblasted with 50-µm Al2O3; and Group L; irradiated with an Er;YAG laser. A translucent shade of resin cement (Rely X Veneer, 3M ESPE) was chosen for cementation. The color values of the veneers were measured with a colorimeter and translucency parameter (TP) values were calculated. A three-way ANOVA with interactions for TP values was performed and Bonferroni tests were used when appropriate (α=0.05). RESULTS There were significant interactions between the surface treatments, ceramic shades and thicknesses (P=.001). For the 0.5-mm-thick specimens there were significant differences after the SB and L treatments. There was no significant difference between the HF and C treatments for any shades or thicknesses (P>.05). For the 1-mm-thick ceramics, there was only a significant difference between the L and C treatments for the HT shade ceramics (P=.01). There were also significant differences between the SB and C treatments except not for the HO shades (P=.768). CONCLUSION The SB and L treatments caused laminate veneers to become more opaque; however, HF treatment did not affect the TP values. When the laminate veneers were thinner, both the shade of the ceramic and the SB and laser treatments had a greater effect on the TP values. PMID:24605200

  20. Manure Injection Affects the Fate of Pirlimycin in Surface Runoff and Soil.

    PubMed

    Kulesza, Stephanie B; Maguire, Rory O; Xia, Kang; Cushman, Julia; Knowlton, Katharine; Ray, Partha

    2016-03-01

    Antibiotics used in animal agriculture are of increasing environmental concern due to the potential for increased antibiotic resistance after land application of manure. Manure application technology may affect the environmental behavior of these antibiotics. Therefore, rainfall simulations were conducted on plots receiving three manure treatments (surface application, subsurface injection, and no manure control) to determine the fate and transport of pirlimycin, an antibiotic commonly used in dairy production. Rainfall simulations were conducted immediately and 7 d after application of dairy manure spiked with 128 ng g (wet weight) pirlimycin. Soil samples were collected from all plots at two depths (0-5 and 5-20 cm). For injection plots, soil was collected from injection slits and between slits. Pirlimycin concentrations were higher in soil within the injection slits compared with surface application plots at 0 and 7 d. Pirlimycin concentrations in the 0- to 5-cm depth decreased by 30, 55, and 87% in the injection slit, between injection slits, and surface application plots 7 d after application. Pirlimycin concentrations were 106 ng g in sediment and 4.67 ng mL in water from the surface application plots, which were 21 and 32 times that of the injection plots, respectively. After 7 d, pirlimycin levels in runoff sediment and water decreased 80 to 98%. Surface application resulted in six and three times higher pirlimycin concentrations in water and sediment than injection. These results indicate that pirlimycin is most susceptible to loss immediately after manure application. Thus, injection could be considered a best management practice to prevent loss of antibiotics in surface runoff. PMID:27065398

  1. Beyond the cell surface: new mechanisms of receptor function.

    PubMed

    Ibáñez, Carlos F

    2010-05-21

    The text book view of cell surface receptors depicts them at the top of a vertical chain of command that starts with ligand binding and proceeds in a lineal fashion towards the cell nucleus. Although pedagogically useful, this view is incomplete and recent findings suggest that the extracellular domain of cell surface receptors can be a transmitter as much as a receiver in intercellular communication. GFRalpha1 is a GPI-anchored receptor for GDNF (glial cell line-derived neurotrophic factor), a neuronal growth factor with widespread functions in the developing and adult nervous system. GFRalpha1 partners with transmembrane proteins, such as the receptor tyrosine kinase RET or the cell adhesion molecule NCAM, for intracellular transmission of the GDNF signal. In addition to this canonical role, GFRalpha1 can also engage in horizontal interactions and thereby modify the function of other cell surface components. GFRalpha1 can also function as a ligand-induced adhesion cell molecule, mediating homophilic cell-cell interactions in response to GDNF. Finally, GFRalpha1 can also be released from the cell surface and act at a distance as a soluble factor together with its ligand. This plethora of unconventional mechanisms is likely to be a feature common to several other receptors and considerably expands our view of cell surface receptor function. PMID:20494105

  2. Amylolytic hydrolysis of native starch granules affected by granule surface area.

    PubMed

    Kim, J C; Kong, B W; Kim, M J; Lee, S H

    2008-11-01

    Initial stage of hydrolysis of native starch granules with various amylolytic enzymes, alpha-amylase from Bacillus subtilis, glucoamylase I (GA-I) and II (GA-II) from Aspergillus niger, and beta-amylase from sweet potato showed that the reaction was apparently affected by a specific surface area of the starch granules. The ratios of the reciprocal of initial velocity of each amylolytic hydrolysis for native potato and maize starch to that for rice with the amylolytic enzymes were nearly equivalent to the ratio of surface area per mass of the 2 starch granules to that of rice, that is, 6.94 and 2.25, respectively. Thus, the reciprocal of initial velocity of each enzymatic hydrolysis as expressed in a Lineweaver-Burk plot was a linear function of the reciprocal of surface area for each starch granule. As a result, it is concluded that amylolytic hydrolysis of native starch granules is governed by the specific surface area, not by the mass concentration, of each granule. PMID:19021791

  3. Amylolytic hydrolysis of native starch granules affected by granule surface area.

    PubMed

    Kim, J C; Kong, B W; Kim, M J; Lee, S H

    2008-11-01

    Initial stage of hydrolysis of native starch granules with various amylolytic enzymes, alpha-amylase from Bacillus subtilis, glucoamylase I (GA-I) and II (GA-II) from Aspergillus niger, and beta-amylase from sweet potato showed that the reaction was apparently affected by a specific surface area of the starch granules. The ratios of the reciprocal of initial velocity of each amylolytic hydrolysis for native potato and maize starch to that for rice with the amylolytic enzymes were nearly equivalent to the ratio of surface area per mass of the 2 starch granules to that of rice, that is, 6.94 and 2.25, respectively. Thus, the reciprocal of initial velocity of each enzymatic hydrolysis as expressed in a Lineweaver-Burk plot was a linear function of the reciprocal of surface area for each starch granule. As a result, it is concluded that amylolytic hydrolysis of native starch granules is governed by the specific surface area, not by the mass concentration, of each granule.

  4. Clinorotation affects mesophyll photosynthetic cells in leaves of pea seedlings.

    PubMed

    Adamchuk, N I

    1998-07-01

    Experiments with autotrophs in altered gravity condition have a grate significant for development of space biology. The main results of investigation in the photosynthetic apparatus state under microgravity condition have based on the experiments with maturity plants and their differentiated cells. The structural and functional organization of photosynthetic cells in seedlings is poor understandable still. Along with chloroplasts preserving a native membrane system in palisade parenchyma cells of the 29-day pea plant leaves in microgravity, chloroplasts with fribly packed or damaged granae, whose thylakoids appeared as vesicles with an electrontransparent content, were also observed. The investigation of preceding process induced these effects have a sense. That is why, the goal of our experiments was to perform the study of a structural organization of the photosynthetic cells of 3-d pair of pea seedlings leaves under the influence of clinorotation.

  5. Cell Surface Proteome of Dental Pulp Stem Cells Identified by Label-Free Mass Spectrometry

    PubMed Central

    Niehage, Christian; Karbanová, Jana; Steenblock, Charlotte

    2016-01-01

    Multipotent mesenchymal stromal cells (MSCs) are promising tools for regenerative medicine. They can be isolated from different sources based on their plastic-adherence property. The identification of reliable cell surface markers thus becomes the Holy Grail for their prospective isolation. Here, we determine the cell surface proteomes of human dental pulp-derived MSCs isolated from single donors after culture expansion in low (2%) or high (10%) serum-containing media. Cell surface proteins were tagged on intact cells using cell impermeable, cleavable sulfo-NHS-SS-biotin, which allows their enrichment by streptavidin pull-down. For the proteomic analyses, we first compared label-free methods to analyze cell surface proteomes i.e. composition, enrichment and proteomic differences, and we developed a new mathematical model to determine cell surface protein enrichment using a combinatorial gene ontology query. Using this workflow, we identified 101 cluster of differentiation (CD) markers and 286 non-CD cell surface proteins. Based on this proteome profiling, we identified 14 cell surface proteins, which varied consistently in abundance when cells were cultured under low or high serum conditions. Collectively, our analytical methods provide a basis for identifying the cell surface proteome of dental pulp stem cells isolated from single donors and its evolution during culture or differentiation. Our data provide a comprehensive cell surface proteome for the precise identification of dental pulp-derived MSC populations and their isolation for potential therapeutic intervention. PMID:27490675

  6. Cell Surface Proteome of Dental Pulp Stem Cells Identified by Label-Free Mass Spectrometry.

    PubMed

    Niehage, Christian; Karbanová, Jana; Steenblock, Charlotte; Corbeil, Denis; Hoflack, Bernard

    2016-01-01

    Multipotent mesenchymal stromal cells (MSCs) are promising tools for regenerative medicine. They can be isolated from different sources based on their plastic-adherence property. The identification of reliable cell surface markers thus becomes the Holy Grail for their prospective isolation. Here, we determine the cell surface proteomes of human dental pulp-derived MSCs isolated from single donors after culture expansion in low (2%) or high (10%) serum-containing media. Cell surface proteins were tagged on intact cells using cell impermeable, cleavable sulfo-NHS-SS-biotin, which allows their enrichment by streptavidin pull-down. For the proteomic analyses, we first compared label-free methods to analyze cell surface proteomes i.e. composition, enrichment and proteomic differences, and we developed a new mathematical model to determine cell surface protein enrichment using a combinatorial gene ontology query. Using this workflow, we identified 101 cluster of differentiation (CD) markers and 286 non-CD cell surface proteins. Based on this proteome profiling, we identified 14 cell surface proteins, which varied consistently in abundance when cells were cultured under low or high serum conditions. Collectively, our analytical methods provide a basis for identifying the cell surface proteome of dental pulp stem cells isolated from single donors and its evolution during culture or differentiation. Our data provide a comprehensive cell surface proteome for the precise identification of dental pulp-derived MSC populations and their isolation for potential therapeutic intervention. PMID:27490675

  7. T Cell Activation Thresholds are Affected by Gravitational

    NASA Technical Reports Server (NTRS)

    Adams, Charley; Gonzalez, M.; Nelman-Gonzalez, M.

    1999-01-01

    T cells stimulated in space flight by various mitogenic signals show a dramatic reduction in proliferation and expression of early activation markers. Similar results are also obtained in a ground based model of microgravity, clinorotation, which provides a vector-averaged reduction of the apparent gravity on cells without significant shear force. Here we demonstrate that T cell inhibition is due to an increase in the required threshold for activation. Dose response curves indicate that cells activated during clinorotation require higher stimulation to achieve the same level of activation, as measured by CD69 expression. Interleukin 2 receptor expression, and DNA synthesis. The amount of stimulation necessary for 50% activation is 5 fold in the clinostat relative to static. Correlation of TCR internalization with activation also exhibit a dramatic right shift in clinorotation, demonstrating unequivocally that signal transduction mechanism independent of TCR triggering account for the increased activation threshold. Previous results from space flight experiments are consistent with the dose response curves obtained for clinorotation. Activation thresholds are important aspects of T cell memory, autoimmunity and tolerance Clinorotation is a useful, noninvasive tool for the study of cellular and biochemical event regulating T cell activation threshold and the effects of gravitation forces on these systems.

  8. Amber mutation affecting the length of Escherichia coli cells.

    PubMed Central

    Martínez-Salas, E; Vicente, M

    1980-01-01

    An amber mutation in a newly found gene (wee) of Escherichia coli has been isolated from strain OV-2, which harbors a temperature-sensitive suppressor. At 42 degrees C cells of the mutant, OV-25, increased in mass and deoxyribonucleic acid content and divided at normal rates, compared with the wild type under the same growth conditions. Total cell length increased under the restrictive conditions, although at a slightly lower rate. Values of mean cell length and cell volume, contrary to what would be expected from the increment in the rate of increase in particles, mass, and deoxyribonucleic acid, became at 42 degrees C smaller than those found in the wild type. A parallel increase in protein content per length and cell density and a loss of viability were found to occur after four generations at the restrictive temperature. The behavior of strain OV-25 in the absence of the wee gene product could be interpreted in terms of either a faulty regulation of the elongation processes or their abnormal coordination with the cell cycle. The genetic location of the wee gene has been found to be at 83.5 min on the E. coli genetic map. PMID:7000749

  9. Cell multiplication following partial enzymatic removal of surface coat.

    PubMed

    Wyroba, E

    1978-08-01

    Treatment of Paramecium aurelia with trypsin or pronase (1 mg per 10(5) cells, at 0 to 4 degrees C) partially removes the surface coat and modifies significantly multiplication of cells. The division rate after 24 hours of cultivation is diminished approximately twice in the case of pronase-treated cells and 1.5 for tyrpsin-digested ciliates as compared with the control. On the second day the division rate increases rapidly and number of cell divisions exceeds the values observed in the control. After 72 hours of cultivation the division rate in both untreated and enzyme-treated cells is almost the same. It is concluded that the observed inhibition of cell fission results from the enzymatic removal of the surface coat--the integrity of this surface coat seems to be necessary in the process of cell division. The influence of environmental factors on the rate of growth is presented.

  10. Cell Surface Changes Associated with Cellular Immune Reactions in Drosophila

    NASA Astrophysics Data System (ADS)

    Nappi, Anthony J.; Silvers, Michael

    1984-09-01

    In Drosophila melanogaster a temperature-induced change in immune competence accompanies cell surface alterations that cause its blood cells to adhere and to encapsulate a parasite. At 29 degrees C the blood cells of the tumorous-lethal (Tuml) mutant show a high degree of immune competence and encapsulate the eggs of the parasitic wasp Leptopilina heterotoma. At 21 degrees C the blood cells are essentially immune incompetent. High percentages of lectin binding cells were found under conditions which potentiated cellular encapsulation responses. Some immune reactive blood cells did not bind lectin. The low percentages of lectin binding cells in susceptible hosts suggest that developing parasites alter the cell surface of the blood cells of immune reactive hosts.

  11. Cell surface changes associated with cellular immune reactions in Drosophila.

    PubMed

    Nappi, A J; Silvers, M

    1984-09-14

    In Drosophila melanogaster a temperature-induced change in immune competence accompanies cell surface alterations that cause its blood cells to adhere and to encapsulate a parasite. At 29 degrees C the blood cells of the tumorous-lethal (Tuml) mutant show a high degree of immune competence and encapsulate the eggs of the parasitic wasp Leptopilina heterotoma. At 21 degrees C the blood cells are essentially immune incompetent. High percentages of lectin binding cells were found under conditions which potentiated cellular encapsulation responses. Some immune reactive blood cells did not bind lectin. The low percentages of lectin binding cells in susceptible hosts suggest that developing parasites alter the cell surface of the blood cells of immune reactive hosts. PMID:6433482

  12. Myotube formation is affected by adipogenic lineage cells in a cell-to-cell contact-independent manner

    SciTech Connect

    Takegahara, Yuki; Yamanouchi, Keitaro Nakamura, Katsuyuki; Nakano, Shin-ichi; Nishihara, Masugi

    2014-05-15

    Intramuscular adipose tissue (IMAT) formation is observed in some pathological conditions such as Duchenne muscular dystrophy (DMD) and sarcopenia. Several studies have suggested that IMAT formation is not only negatively correlated with skeletal muscle mass but also causes decreased muscle contraction in sarcopenia. In the present study, we examined w hether adipocytes affect myogenesis. For this purpose, skeletal muscle progenitor cells were transfected with siRNA of PPARγ (siPPARγ) in an attempt to inhibit adipogenesis. Myosin heavy chain (MHC)-positive myotube formation was promoted in cells transfected with siPPARγ compared to that of cells transfected with control siRNA. To determine whether direct cell-to-cell contact between adipocytes and myoblasts is a prerequisite for adipocytes to affect myogenesis, skeletal muscle progenitor cells were cocultured with pre- or mature adipocytes in a Transwell coculture system. MHC-positive myotube formation was inhibited when skeletal muscle progenitor cells were cocultured with mature adipocytes, but was promoted when they were cocultured with preadipocytes. Similar effects were observed when pre- or mature adipocyte-conditioned medium was used. These results indicate that preadipocytes play an important role in maintaining skeletal muscle mass by promoting myogenesis; once differentiated, the resulting mature adipocytes negatively affect myogenesis, leading to the muscle deterioration observed in skeletal muscle pathologies. - Highlights: • We examined the effects of pre- and mature adipocytes on myogenesis in vitro. • Preadipocytes and mature adipocytes affect myoblast fusion. • Preadipocytes play an important role in maintaining skeletal muscle mass. • Mature adipocytes lead to muscle deterioration observed in skeletal muscle pathologies.

  13. Inhibition of HIF-1α Affects Autophagy Mediated Glycosylation in Oral Squamous Cell Carcinoma Cells

    PubMed Central

    Li, Yi-Ning; Hu, Ji-An; Wang, Hui-Ming

    2015-01-01

    Purpose. To validate the function of autophagy with the regulation of hypoxia inhibitor-induced glycosylation in oral squamous cell carcinoma cell. Methods. Human Tca8113 cell line was used to detect autophagy and glycosylation related protein expression by western blotting and immunofluorescence with HIF-1α inhibitor. Short interfering RNA (siRNA) transfection blocked human ATG12 and ATG1. Results. HIF-1α inhibitor PX-478 reduced the amount of LC3-II and LC3-I in Tca8113 cells. PX-478 decreased the expression of O-GlcNAc and OGT and increased OGA expression. The tendency of O-GlcNAc showed a similar pattern to OGT. PX-478 gradually decreased OGT expression in Tca8113 cells. Protein level of O-GlcNAc and OGT increased in ATG12 and ATG1 depletion. The expression of OGT decreased at first and then rose slowly with the treatment of Atg12 and Atg1 siRNA and PX-478 fluctuant. Autophagy affected the stability of OGT when HIF-1α signaling was blocked. Conclusions. Autophagy reduced by hypoxic stress inhibited. HIF-1α inhibitor decreased glycosylation. OGT became unstable in the absence of autophagy when HIF-1α signaling was blocked. PMID:26640316

  14. Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces

    PubMed Central

    Rejmontová, Petra; Capáková, Zdenka; Mikušová, Nikola; Maráková, Nela; Kašpárková, Věra; Lehocký, Marián; Humpolíček, Petr

    2016-01-01

    Polyaniline shows great potential and promises wide application in the biomedical field thanks to its intrinsic conductivity and material properties, which closely resemble natural tissues. Surface properties are crucial, as these predetermine any interaction with biological fluids, proteins and cells. An advantage of polyaniline is the simple modification of its surface, e.g., by using various dopant acids. An investigation was made into the adhesion, proliferation and migration of mouse embryonic fibroblasts on pristine polyaniline films and films doped with sulfamic and phosphotungstic acids. In addition, polyaniline films supplemented with poly (2-acrylamido-2-methyl-1-propanesulfonic) acid at various ratios were tested. Results showed that the NIH/3T3 cell line was able to adhere, proliferate and migrate on the pristine polyaniline films as well as those films doped with sulfamic and phosphotungstic acids; thus, utilization of said forms in biomedicine appears promising. Nevertheless, incorporating poly (2-acrylamido-2-methyl-1-propanesulfonic) acid altered the surface properties of the polyaniline films and significantly affected cell behavior. In order to reveal the crucial factor influencing the surface/cell interaction, cell behavior is discussed in the context of the surface energy of individual samples. It was clearly demonstrated that the lesser the difference between the surface energy of the sample and cell, the more cyto-compatible the surface is. PMID:27649159

  15. Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces.

    PubMed

    Rejmontová, Petra; Capáková, Zdenka; Mikušová, Nikola; Maráková, Nela; Kašpárková, Věra; Lehocký, Marián; Humpolíček, Petr

    2016-01-01

    Polyaniline shows great potential and promises wide application in the biomedical field thanks to its intrinsic conductivity and material properties, which closely resemble natural tissues. Surface properties are crucial, as these predetermine any interaction with biological fluids, proteins and cells. An advantage of polyaniline is the simple modification of its surface, e.g., by using various dopant acids. An investigation was made into the adhesion, proliferation and migration of mouse embryonic fibroblasts on pristine polyaniline films and films doped with sulfamic and phosphotungstic acids. In addition, polyaniline films supplemented with poly (2-acrylamido-2-methyl-1-propanesulfonic) acid at various ratios were tested. Results showed that the NIH/3T3 cell line was able to adhere, proliferate and migrate on the pristine polyaniline films as well as those films doped with sulfamic and phosphotungstic acids; thus, utilization of said forms in biomedicine appears promising. Nevertheless, incorporating poly (2-acrylamido-2-methyl-1-propanesulfonic) acid altered the surface properties of the polyaniline films and significantly affected cell behavior. In order to reveal the crucial factor influencing the surface/cell interaction, cell behavior is discussed in the context of the surface energy of individual samples. It was clearly demonstrated that the lesser the difference between the surface energy of the sample and cell, the more cyto-compatible the surface is. PMID:27649159

  16. Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces.

    PubMed

    Rejmontová, Petra; Capáková, Zdenka; Mikušová, Nikola; Maráková, Nela; Kašpárková, Věra; Lehocký, Marián; Humpolíček, Petr

    2016-09-15

    Polyaniline shows great potential and promises wide application in the biomedical field thanks to its intrinsic conductivity and material properties, which closely resemble natural tissues. Surface properties are crucial, as these predetermine any interaction with biological fluids, proteins and cells. An advantage of polyaniline is the simple modification of its surface, e.g., by using various dopant acids. An investigation was made into the adhesion, proliferation and migration of mouse embryonic fibroblasts on pristine polyaniline films and films doped with sulfamic and phosphotungstic acids. In addition, polyaniline films supplemented with poly (2-acrylamido-2-methyl-1-propanesulfonic) acid at various ratios were tested. Results showed that the NIH/3T3 cell line was able to adhere, proliferate and migrate on the pristine polyaniline films as well as those films doped with sulfamic and phosphotungstic acids; thus, utilization of said forms in biomedicine appears promising. Nevertheless, incorporating poly (2-acrylamido-2-methyl-1-propanesulfonic) acid altered the surface properties of the polyaniline films and significantly affected cell behavior. In order to reveal the crucial factor influencing the surface/cell interaction, cell behavior is discussed in the context of the surface energy of individual samples. It was clearly demonstrated that the lesser the difference between the surface energy of the sample and cell, the more cyto-compatible the surface is.

  17. Cell-Surface Phenol Soluble Modulins Regulate Staphylococcus aureus Colony Spreading

    PubMed Central

    Kizaki, Hayato; Omae, Yosuke; Tabuchi, Fumiaki; Saito, Yuki; Sekimizu, Kazuhisa

    2016-01-01

    Staphylococcus aureus produces phenol-soluble modulins (PSMs), which are amphipathic small peptides with lytic activity against mammalian cells. We previously reported that PSMα1–4 stimulate S. aureus colony spreading, the phenomenon of S. aureus colony expansion on the surface of soft agar plates, whereas δ-toxin (Hld, PSMγ) inhibits colony-spreading activity. In this study, we revealed the underlying mechanism of the opposing effects of PSMα1–4 and δ-toxin in S. aureus colony spreading. PSMα1–4 and δ-toxin are abundant on the S. aureus cell surface, and account for 18% and 8.5% of the total amount of PSMα1–4 and δ-toxin, respectively, in S. aureus overnight cultures. Knockout of PSMα1–4 did not affect the amount of cell surface δ-toxin. In contrast, knockout of δ-toxin increased the amount of cell surface PSMα1–4, and decreased the amount of culture supernatant PSMα1–4. The δ-toxin inhibited PSMα3 and PSMα2 binding to the S. aureus cell surface in vitro. A double knockout strain of PSMα1–4 and δ-toxin exhibited decreased colony spreading compared with the parent strain. Expression of cell surface PSMα1–4, but not culture supernatant PSMα1–4, restored the colony-spreading activity of the PSMα1-4/δ-toxin double knockout strain. Expression of δ-toxin on the cell surface or in the culture supernatant did not restore the colony-spreading activity of the PSMα1-4/δ-toxin double knockout strain. These findings suggest that cell surface PSMα1–4 promote S. aureus colony spreading, whereas δ-toxin suppresses colony-spreading activity by inhibiting PSMα1–4 binding to the S. aureus cell surface. PMID:27723838

  18. Low Temperature Affects Stem Cell Maintenance in Brassica oleracea Seedlings

    PubMed Central

    de Jonge, Jennifer; Kodde, Jan; Severing, Edouard I.; Bonnema, Guusje; Angenent, Gerco C.; Immink, Richard G. H.; Groot, Steven P. C.

    2016-01-01

    Most of the above ground tissues in higher plants originate from stem cells located in the shoot apical meristem (SAM). Several plant species can suffer from spontaneous stem cell arrest resulting in lack of further shoot development. In Brassica oleracea this SAM arrest is known as blindness and occurs in an unpredictable manner leading to considerable economic losses for plant raisers and farmers. Detailed analyses of seedlings showed that stem cell arrest is triggered by low temperatures during germination. To induce this arrest reproducibly and to study the effect of the environment, an assay was developed. The role of genetic variation on the susceptibility to develop blind seedlings was analyzed by a quantitative genetic mapping approach, using seeds from a double haploid population from a cross between broccoli and Chinese kale, produced at three locations. The analysis revealed, besides an effect of the seed production location, a region on linkage group C3 associated with blindness sensitivity. A subsequent dynamic genome-wide transcriptome analysis resulted in the identification of around 3000 differentially expressed genes early after blindness induction. A large number of cell cycle genes were en masse induced early during the development of blindness, whereas shortly after, all were down-regulated. This miss-regulation of core cell cycle genes is accompanied with a strong reduction of cells reaching the DNA replication phase. From the differentially expressed genes, 90 were located in the QTL region C3. Among them are two genes belonging to the MINICHROMOSOMAL MAINTENANCE gene family, known to be involved in DNA replication, a RETINOBLASTOMA-RELATED gene, a key regulator for cell cycle initiation, and several MutS homologs genes, involved in DNA repair. These genes are potential candidates for being involved in the development of blindness in Brassica oleracea sensitive genotypes. PMID:27375654

  19. New thiazolidinediones affect endothelial cell activation and angiogenesis.

    PubMed

    Rudnicki, Martina; Tripodi, Gustavo L; Ferrer, Renila; Boscá, Lisardo; Pitta, Marina G R; Pitta, Ivan R; Abdalla, Dulcineia S P

    2016-07-01

    Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor-γ (PPARγ) agonists used in treating type 2 diabetes that may exhibit beneficial pleiotropic effects on endothelial cells. In this study, we characterized the effects of three new TZDs [GQ-32 (3-biphenyl-4-ylmethyl-5-(4-nitro-benzylidene)-thiazolidine-2,4-dione), GQ-169 (5-(4-chloro-benzylidene)-3-(2,6-dichloro-benzyl)-thiazolidine-2,4-dione), and LYSO-7 (5-(5-bromo-1H-indol-3-ylmethylene)-3-(4-chlorobenzyl)-thiazolidine-2,4-dione)] on endothelial cells. The effects of the new TZDs were evaluated on the production of nitric oxide (NO) and reactive oxygen species (ROS), cell migration, tube formation and the gene expression of adhesion molecules and angiogenic mediators in human umbilical vein endothelial cells (HUVECs). PPARγ activation by new TZDs was addressed with a reporter gene assay. The three new TZDs activated PPARγ and suppressed the tumor necrosis factor α-induced expression of vascular cell adhesion molecule 1 and intercellular adhesion molecule 1. GQ-169 and LYSO-7 also inhibited the glucose-induced ROS production. Although NO production assessed with 4-amino-5-methylamino-2',7'-difluorofluorescein-FM probe indicated that all tested TZDs enhanced intracellular levels of NO, only LYSO-7 treatment significantly increased the release of NO from HUVEC measured by chemiluminescence analysis of culture media. Additionally, GQ-32 and GQ-169 induced endothelial cell migration and tube formation by the up-regulation of angiogenic molecules expression, such as vascular endothelial growth factor A and interleukin 8. GQ-169 also increased the mRNA levels of basic fibroblast growth factor, and GQ-32 enhanced transforming growth factor-β expression. Together, the results of this study reveal that these new TZDs act as partial agonists of PPARγ and modulate endothelial cell activation and endothelial dysfunction besides to stimulate migration and tube formation. PMID:27108791

  20. Low Temperature Affects Stem Cell Maintenance in Brassica oleracea Seedlings.

    PubMed

    de Jonge, Jennifer; Kodde, Jan; Severing, Edouard I; Bonnema, Guusje; Angenent, Gerco C; Immink, Richard G H; Groot, Steven P C

    2016-01-01

    Most of the above ground tissues in higher plants originate from stem cells located in the shoot apical meristem (SAM). Several plant species can suffer from spontaneous stem cell arrest resulting in lack of further shoot development. In Brassica oleracea this SAM arrest is known as blindness and occurs in an unpredictable manner leading to considerable economic losses for plant raisers and farmers. Detailed analyses of seedlings showed that stem cell arrest is triggered by low temperatures during germination. To induce this arrest reproducibly and to study the effect of the environment, an assay was developed. The role of genetic variation on the susceptibility to develop blind seedlings was analyzed by a quantitative genetic mapping approach, using seeds from a double haploid population from a cross between broccoli and Chinese kale, produced at three locations. The analysis revealed, besides an effect of the seed production location, a region on linkage group C3 associated with blindness sensitivity. A subsequent dynamic genome-wide transcriptome analysis resulted in the identification of around 3000 differentially expressed genes early after blindness induction. A large number of cell cycle genes were en masse induced early during the development of blindness, whereas shortly after, all were down-regulated. This miss-regulation of core cell cycle genes is accompanied with a strong reduction of cells reaching the DNA replication phase. From the differentially expressed genes, 90 were located in the QTL region C3. Among them are two genes belonging to the MINICHROMOSOMAL MAINTENANCE gene family, known to be involved in DNA replication, a RETINOBLASTOMA-RELATED gene, a key regulator for cell cycle initiation, and several MutS homologs genes, involved in DNA repair. These genes are potential candidates for being involved in the development of blindness in Brassica oleracea sensitive genotypes. PMID:27375654

  1. Optimized Structure and Vibrational Properties by Error Affected Potential Energy Surfaces

    PubMed Central

    Zen, Andrea; Zhelyazov, Delyan; Guidoni, Leonardo

    2013-01-01

    The precise theoretical determination of the geometrical parameters of molecules at the minima of their potential energy surface and of the corresponding vibrational properties are of fundamental importance for the interpretation of vibrational spectroscopy experiments. Quantum Monte Carlo techniques are correlated electronic structure methods promising for large molecules, which are intrinsically affected by stochastic errors on both energy and force calculations, making the mentioned calculations more challenging with respect to other more traditional quantum chemistry tools. To circumvent this drawback in the present work, we formulate the general problem of evaluating the molecular equilibrium structures, the harmonic frequencies, and the anharmonic coefficients of an error affected potential energy surface. The proposed approach, based on a multidimensional fitting procedure, is illustrated together with a critical evaluation of systematic and statistical errors. We observe that the use of forces instead of energies in the fitting procedure reduces the statistical uncertainty of the vibrational parameters by 1 order of magnitude. Preliminary results based on variational Monte Carlo calculations on the water molecule demonstrate the possibility to evaluate geometrical parameters and harmonic and anharmonic coefficients at this level of theory with an affordable computational cost and a small stochastic uncertainty (<0.07% for geometries and <0.7% for vibrational properties). PMID:24093004

  2. Controlling Gel Structure to Modulate Cell Adhesion and Spreading on the Surface of Microcapsules.

    PubMed

    Zheng, Huizhen; Gao, Meng; Ren, Ying; Lou, Ruyun; Xie, Hongguo; Yu, Weiting; Liu, Xiudong; Ma, Xiaojun

    2016-08-01

    The surface properties of implanted materials or devices play critical roles in modulating cell behavior. However, the surface properties usually affect cell behaviors synergetically so that it is still difficult to separately investigate the influence of a single property on cell behavior in practical applications. In this study, alginate-chitosan (AC) microcapsules with a dense or loose gel structure were fabricated to understand the effect of gel structure on cell behavior. Cells preferentially adhered and spread on the loose gel structure microcapsules rather than on the dense ones. The two types of microcapsules exhibited nearly identical surface positive charges, roughness, stiffness, and hydrophilicity; thus, the result suggested that the gel structure was the principal factor affecting cell behavior. X-ray photoelectron spectroscopy analyses demonstrated that the overall percentage of positively charged amino groups was similar on both microcapsules. The different gel structures led to different states and distributions of the positively charged amino groups of chitosan, so we conclude that the loose gel structure facilitated greater cell adhesion and spreading mainly because more protonated amino groups remained unbound and exposed on the surface of these microcapsules.

  3. Encephalitis and antibodies to synaptic and neuronal cell surface proteins

    PubMed Central

    Lancaster, Eric; Martinez-Hernandez, Eugenia

    2011-01-01

    The identification of encephalitis associated with antibodies against cell surface and synaptic proteins, although recent, has already had a substantial impact in clinical neurology and neuroscience. The target antigens are receptors and proteins that have critical roles in synaptic transmission and plasticity, including the NMDA receptor, the AMPA receptor, the GABAB receptor, and the glycine receptor. Other autoantigens, such as leucine-rich glioma-inactivated 1 and contactin-associated protein-like 2, form part of trans-synaptic complexes and neuronal cell adhesion molecules involved in fine-tuning synaptic transmission and nerve excitability. Syndromes resulting from these immune responses resemble those of pharmacologic or genetic models in which the antigens are disrupted. For some immune responses, there is evidence that the antibodies alter the structure and function of the antigen, suggesting a direct pathogenic effect. These disorders are important because they can affect children and young adults, are severe and protracted, occur with or without tumor association, and respond to treatment but may relapse. This review provides an update on these syndromes and autoantigens with special emphasis on clinical diagnosis and treatment. PMID:21747075

  4. Post-transcriptional RNA Regulons Affecting Cell Cycle and Proliferation

    PubMed Central

    Blackinton, Jeff G.

    2014-01-01

    The cellular growth cycle is initiated and maintained by punctual, yet agile, regulatory events involving modifications of cell cycle proteins as well as coordinated gene expression to support cyclic checkpoint decisions. Recent evidence indicates that post-transcriptional partitioning of messenger RNA subsets by RNA-binding proteins help physically localize, temporally coordinate, and efficiently translate cell cycle proteins. This dynamic organization of mRNAs encoding cell cycle components contributes to the overall economy of the cell cycle consistent with the post-transcriptional RNA regulon model of gene expression. This review examines several recent studies demonstrating the coordination of mRNA subsets encoding cell cycle proteins during nuclear export and subsequent coupling to protein synthesis, and discusses evidence for mRNA coordination of p53 targets and the DNA damage response pathway. We consider how these observations may connect to upstream and downstream post-transcriptional coordination and coupling of splicing, export, localization, and translation. Published examples from yeast, nematode, insect, and mammalian systems are discussed, and we consider genetic evidence supporting the conclusion that dysregulation of RNA regulons may promote pathogenic states of growth such as carcinogenesis. PMID:24882724

  5. Allyl isothiocyanate affects the cell cycle of Arabidopsis thaliana

    PubMed Central

    Åsberg, Signe E.; Bones, Atle M.; Øverby, Anders

    2015-01-01

    Isothiocyanates (ITCs) are degradation products of glucosinolates present in members of the Brassicaceae family acting as herbivore repellents and antimicrobial compounds. Recent results indicate that allyl ITC (AITC) has a role in defense responses such as glutathione depletion, ROS generation and stomatal closure. In this study we show that exposure to non-lethal concentrations of AITC causes a shift in the cell cycle distribution of Arabidopsis thaliana leading to accumulation of cells in S-phases and a reduced number of cells in non-replicating phases. Furthermore, transcriptional analysis revealed an AITC-induced up-regulation of the gene encoding cyclin-dependent kinase A while several genes encoding mitotic proteins were down-regulated, suggesting an inhibition of mitotic processes. Interestingly, visualization of DNA synthesis indicated that exposure to AITC reduced the rate of DNA replication. Taken together, these results indicate that non-lethal concentrations of AITC induce cells of A. thaliana to enter the cell cycle and accumulate in S-phases, presumably as a part of a defensive response. Thus, this study suggests that AITC has several roles in plant defense and add evidence to the growing data supporting a multifunctional role of glucosinolates and their degradation products in plants. PMID:26042144

  6. Monoterpene (-)-citronellal affects hepatocarcinoma cell signaling via an olfactory receptor.

    PubMed

    Maßberg, Désirée; Simon, Annika; Häussinger, Dieter; Keitel, Verena; Gisselmann, Günter; Conrad, Heike; Hatt, Hanns

    2015-01-15

    Terpenes are the major constituents of essential oils in plants. In recent years, terpenes have become of clinical relevance due to their ability to suppress cancer development. Their effect on cellular proliferation has made them promising agents in the prevention or treatment of many types of cancer. In the present study, a subset of different monoterpenes was investigated for their molecular effects on the hepatocellular carcinoma cell line Huh7. Using fluorometric calcium imaging, acyclic monoterpene (-)-citronellal was found to induce transient Ca(2+) signals in Huh7 cells by activating a cAMP-dependent signaling pathway. Moreover, we detected the (-)-citronellal-activated human olfactory receptor OR1A2 at the mRNA and protein levels and demonstrated its potential involvement in (-)-citronellal-induced calcium signaling in Huh7 cells. Furthermore, activation of OR1A2 results in phosphorylation of p38 MAPK and reduced cell proliferation, indicating an effect on hepatocellular carcinoma progression. Here, we provide for the first time data on the molecular mechanism evoked by (-)-citronellal in human hepatocellular carcinoma cells. The identified olfactory receptor could serve as a potential therapeutic target for cancer diagnosis and treatment.

  7. Cobalt and chromium exposure affects osteoblast function and impairs the mineralization of prosthesis surfaces in vitro.

    PubMed

    Shah, Karan M; Wilkinson, Jeremy Mark; Gartland, Alison

    2015-11-01

    Cobalt (Co) and chromium (Cr) ions and nanoparticles equivalent to those released through tribo-corrosion of prosthetic metal-on-metal (MOM) bearings and taper junctions are detrimental to osteoblast activity and function in vitro when examined as individual species. Here we examined the effects of Co(2+):Cr(3+) and Co(2+):Cr(6+) combinations on osteoblast-like SaOS-2 cellular activity, alkaline phosphatase (ALP) activity and mineralization to better reflect clinical exposure conditions in vivo. We also assessed the effect of Co(2+):Cr(3+) combinations and Co:Cr nanoparticles on SaOS-2 cell osteogenic responses on grit-blasted, plasma-sprayed titanium-coated, and hydroxyapatite-coated prosthesis surfaces. Cellular activity and ALP activity were reduced to a greater extent with combination treatments compared to individual ions. Co(2+) and Cr(3+) interacted additively and synergistically to reduce cellular activity and ALP activity, respectively, while the Co(2+) with Cr(6+) combination was dominated by the effect of Cr(6+) alone. Mineralization by osteoblasts was greater on hydroxyapatite-coated surfaces compared to grit-blasted and plasma-sprayed titanium-coated surfaces. Treatments with Co(2+):Cr(3+) ions and Co:Cr nanoparticles reduced the percentage mineralization on all surfaces, with hydroxyapatite-coated surfaces having the least reduction. In conclusion, our data suggests that previous studies investigating individual metal ions underestimate their potential clinical effects on osteoblast activity. Furthermore, the data suggests that hydroxyapatite-coated surfaces may modulate osteoblast responses to metal debris.

  8. Attachment and invasion of Neisseria meningitidis to host cells is related to surface hydrophobicity, bacterial cell size and capsule.

    PubMed

    Bartley, Stephanie N; Tzeng, Yih-Ling; Heel, Kathryn; Lee, Chiang W; Mowlaboccus, Shakeel; Seemann, Torsten; Lu, Wei; Lin, Ya-Hsun; Ryan, Catherine S; Peacock, Christopher; Stephens, David S; Davies, John K; Kahler, Charlene M

    2013-01-01

    We compared exemplar strains from two hypervirulent clonal complexes, strain NMB-CDC from ST-8/11 cc and strain MC58 from ST-32/269 cc, in host cell attachment and invasion. Strain NMB-CDC attached to and invaded host cells at a significantly greater frequency than strain MC58. Type IV pili retained the primary role for initial attachment to host cells for both isolates regardless of pilin class and glycosylation pattern. In strain MC58, the serogroup B capsule was the major inhibitory determinant affecting both bacterial attachment to and invasion of host cells. Removal of terminal sialylation of lipooligosaccharide (LOS) in the presence of capsule did not influence rates of attachment or invasion for strain MC58. However, removal of either serogroup B capsule or LOS sialylation in strain NMB-CDC increased bacterial attachment to host cells to the same extent. Although the level of inhibition of attachment by capsule was different between these strains, the regulation of the capsule synthesis locus by the two-component response regulator MisR, and the level of surface capsule determined by flow cytometry were not significantly different. However, the diplococci of strain NMB-CDC were shown to have a 1.89-fold greater surface area than strain MC58 by flow cytometry. It was proposed that the increase in surface area without changing the amount of anchored glycolipid capsule in the outer membrane would result in a sparser capsule and increase surface hydrophobicity. Strain NMB-CDC was shown to be more hydrophobic than strain MC58 using hydrophobicity interaction chromatography and microbial adhesion-to-solvents assays. In conclusion, improved levels of adherence of strain NMB-CDC to cell lines was associated with increased bacterial cell surface and surface hydrophobicity. This study shows that there is diversity in bacterial cell surface area and surface hydrophobicity within N. meningitidis which influence steps in meningococcal pathogenesis.

  9. Seasonal Influences on Ground-Surface Water Interactions in an Arsenic-Affected Aquifer in Cambodia

    NASA Astrophysics Data System (ADS)

    Richards, L. A.; Magnone, D.; Van Dongen, B.; Bryant, C.; Boyce, A.; Ballentine, C. J.; Polya, D. A.

    2015-12-01

    Millions of people in South and Southeast Asia consume drinking water daily which contains dangerous levels of arsenic exceeding health-based recommendations [1]. A key control on arsenic mobilization in aquifers in these areas has been controversially identified as the interaction of 'labile' organic matter contained in surface waters with groundwaters and sediments at depth [2-4], which may trigger the release of arsenic from the solid- to aqueous-phase via reductive dissolution of iron-(hyr)oxide minerals [5]. In a field site in Kandal Province, Cambodia, which is an arsenic-affected area typical to others in the region, there are strong seasonal patterns in groundwater flow direction, which are closely related to monsoonal rains [6] and may contribute to arsenic release in this aquifer. The aim of this study is to explore the implications of the high susceptibility of this aquifer system to seasonal changes on potential ground-surface water interactions. The main objectives are to (i) identify key zones where there are likely ground-surface water interactions, (ii) assess the seasonal impact of such interactions and (iii) quantify the influence of interactions using geochemical parameters (such as As, Fe, NO3, NH4, 14C, 3T/3He, δ18O, δ2H). Identifying the zones, magnitude and seasonal influence of ground-surface water interactions elucidates new information regarding potential locations/pathways of arsenic mobilization and/or transport in affected aquifers and may be important for water management strategies in affected areas. This research is supported by NERC (NE/J023833/1) to DP, BvD and CJB and a NERC PhD studentship (NE/L501591/1) to DM. References: [1] World Health Organization, 2008. [2] Charlet & Polya (2006), Elements, 2, 91-96. [3] Harvey et al. (2002), Science, 298, 1602-1606. [4] Lawson et al. (2013), Env. Sci. Technol. 47, 7085 - 7094. [5] Islam et al. (2004), Nature, 430, 68-71. [6] Benner et al. (2008) Appl. Geochem. 23(11), 3072 - 3087.

  10. Effect of Stratification on Surface Properties of Corneal Epithelial Cells

    PubMed Central

    Yáñez-Soto, Bernardo; Leonard, Brian C.; Raghunathan, Vijay Krishna; Abbott, Nicholas L.; Murphy, Christopher J.

    2015-01-01

    Purpose The purpose of this study was to determine the influence of mucin expression in an immortalized human corneal epithelial cell line (hTCEpi) on the surface properties of cells, such as wettability, contact angle, and surface heterogeneity. Methods hTCEpi cells were cultured to confluence in serum-free medium. The medium was then replaced by stratification medium to induce mucin biosynthesis. The mucin expression profile was analyzed using quantitative PCR and Western blotting. Contact angles were measured using a two-immiscible liquid method, and contact angle hysteresis was evaluated by tilting the apparatus and recording advancing and receding contact angles. The spatial distribution of mucins was evaluated with fluorescently labeled lectin. Results hTCEpi cells expressed the three main ocular mucins (MUC1, MUC4, and MUC16) with a maximum between days 1 and 3 of the stratification process. Upon stratification, cells caused a very significant increase in contact angle hysteresis, suggesting the development of spatially discrete and heterogeneously distributed surface features, defined by topography and/or chemical functionality. Although atomic force microscopy measurements showed no formation of appreciable topographic features on the surface of the cells, we observed a significant increase in surface chemical heterogeneity. Conclusions The surface chemical heterogeneity of the corneal epithelium may influence the dynamic behavior of tear film by “pinning” the contact line between the cellular surface and aqueous tear film. Engineering the surface properties of corneal epithelium could potentially lead to novel treatments in dry eye disease. PMID:26747762

  11. Yeast surface display of dehydrogenases in microbial fuel-cells.

    PubMed

    Gal, Idan; Schlesinger, Orr; Amir, Liron; Alfonta, Lital

    2016-12-01

    Two dehydrogenases, cellobiose dehydrogenase from Corynascus thermophilus and pyranose dehydrogenase from Agaricus meleagris, were displayed for the first time on the surface of Saccharomyces cerevisiae using the yeast surface display system. Surface displayed dehydrogenases were used in a microbial fuel cell and generated high power outputs. Surface displayed cellobiose dehydrogenase has demonstrated a midpoint potential of -28mV (vs. Ag/AgCl) at pH=6.5 and was used in a mediator-less anode compartment of a microbial fuel cell producing a power output of 3.3μWcm(-2) using lactose as fuel. Surface-displayed pyranose dehydrogenase was used in a microbial fuel cell and generated high power outputs using different substrates, the highest power output that was achieved was 3.9μWcm(-2) using d-xylose. These results demonstrate that surface displayed cellobiose dehydrogenase and pyranose dehydrogenase may successfully be used in microbial bioelectrochemical systems.

  12. Yeast surface display of dehydrogenases in microbial fuel-cells.

    PubMed

    Gal, Idan; Schlesinger, Orr; Amir, Liron; Alfonta, Lital

    2016-12-01

    Two dehydrogenases, cellobiose dehydrogenase from Corynascus thermophilus and pyranose dehydrogenase from Agaricus meleagris, were displayed for the first time on the surface of Saccharomyces cerevisiae using the yeast surface display system. Surface displayed dehydrogenases were used in a microbial fuel cell and generated high power outputs. Surface displayed cellobiose dehydrogenase has demonstrated a midpoint potential of -28mV (vs. Ag/AgCl) at pH=6.5 and was used in a mediator-less anode compartment of a microbial fuel cell producing a power output of 3.3μWcm(-2) using lactose as fuel. Surface-displayed pyranose dehydrogenase was used in a microbial fuel cell and generated high power outputs using different substrates, the highest power output that was achieved was 3.9μWcm(-2) using d-xylose. These results demonstrate that surface displayed cellobiose dehydrogenase and pyranose dehydrogenase may successfully be used in microbial bioelectrochemical systems. PMID:27459246

  13. Does prolonged cycling of moderate intensity affect immune cell function?

    PubMed Central

    Scharhag, J; Meyer, T; Gabriel, H; Schlick, B; Faude, O; Kindermann, W; Shephard, R

    2005-01-01

    Background: Prolonged exercise may induce temporary immunosuppression with a presumed increased susceptibility for infection. However, there are only few data on immune cell function after prolonged cycling at moderate intensities typical for road cycling training sessions. Methods: The present study examined the influence on immune cell function of 4 h of cycling at a constant intensity of 70% of the individual anaerobic threshold. Interleukin-6 (IL-6) and C-reactive protein (CRP), leukocyte and lymphocyte populations, activities of natural killer (NK), neutrophils, and monocytes were examined before and after exercise, and also on a control day without exercise. Results: Cycling for 4 h induced a moderate acute phase response with increases in IL-6 from 1.0 (SD 0.5) before to 9.6 (5.6) pg/ml 1 h after exercise and CRP from 0.5 (SD 0.4) before to 1.8 (1.3) mg/l 1 day after exercise. Although absolute numbers of circulating NK cells, monocytes, and neutrophils increased during exercise, on a per cell basis NK cell activity, neutrophil and monocyte phagocytosis, and monocyte oxidative burst did not significantly change after exercise. However, a minor effect over time for neutrophil oxidative burst was noted, tending to decrease after exercise. Conclusions: Prolonged cycling at moderate intensities does not seem to seriously alter the function of cells of the first line of defence. Therefore, the influence of a single typical road cycling training session on the immune system is only moderate and appears to be safe from an immunological point of view. PMID:15728699

  14. Multijunction Solar Cell Technology for Mars Surface Applications

    NASA Technical Reports Server (NTRS)

    Stella, Paul M.; Mardesich, Nick; Ewell, Richard C.; Mueller, Robert L.; Endicter, Scott; Aiken, Daniel; Edmondson, Kenneth; Fetze, Chris

    2006-01-01

    Solar cells used for Mars surface applications have been commercial space qualified AM0 optimized devices. Due to the Martian atmosphere, these cells are not optimized for the Mars surface and as a result operate at a reduced efficiency. A multi-year program, MOST (Mars Optimized Solar Cell Technology), managed by JPL and funded by NASA Code S, was initiated in 2004, to develop tools to modify commercial AM0 cells for the Mars surface solar spectrum and to fabricate Mars optimized devices for verification. This effort required defining the surface incident spectrum, developing an appropriate laboratory solar simulator measurement capability, and to develop and test commercial cells modified for the Mars surface spectrum. This paper discusses the program, including results for the initial modified cells. Simulated Mars surface measurements of MER cells and Phoenix Lander cells (2007 launch) are provided to characterize the performance loss for those missions. In addition, the performance of the MER rover solar arrays is updated to reflect their more than two (2) year operation.

  15. Heterojunction solar cell with passivated emitter surface

    DOEpatents

    Olson, J.M.; Kurtz, S.R.

    1994-05-31

    A high-efficiency heterojunction solar cell is described wherein a thin emitter layer (preferably Ga[sub 0.52]In[sub 0.48]P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer. 1 fig.

  16. Heterojunction solar cell with passivated emitter surface

    DOEpatents

    Olson, Jerry M.; Kurtz, Sarah R.

    1994-01-01

    A high-efficiency heterojunction solar cell wherein a thin emitter layer (preferably Ga.sub.0.52 In.sub.0.48 P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer.

  17. Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

    PubMed

    Wittlingerová, Zdena; Macháčková, Jiřina; Petruželková, Anna; Zimová, Magdalena

    2016-03-01

    Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9-140 μg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 μg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 μg/L (1994-1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 μg/L (1998) and further to 1 μg/L (2011) and 1.1 μg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 μg/kg (1998) to 24 (2011) and 30 μg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.

  18. Surface Markers for the Murine Oval Cell Response

    PubMed Central

    Dorrell, Craig; Erker, Laura; Lanxon-Cookson, Kelsea M.; Abraham, Stephanie L.; Victoroff, Tristan; Ro, Simon; Canaday, Pamela S.; Streeter, Philip R.; Grompe, Markus

    2011-01-01

    The biology of progenitor activation in the liver is of considerable medical and scientific interest. The powerful genetic tools available for the mouse make it an ideal model system to study this complex process involving many different cell types. However, reagents for the isolation and study of distinct hepatic subpopulations have been quite limited compared to those available for hematopoietic cells. To produce cell surface reactive reagents more specific for the oval cell response, we generated a new collection of monoclonal antibodies by immunization of Fischer rats with enzymatically dispersed nonparenchymal cells from the livers of adult mice treated with 3,5-diethoxycarbonyl-1,4-dihydrocollidine. Each of the resulting antibodies recognized a surface antigen present on a liver cell subset and permitted the viable isolation of the associated subpopulation by fluorescence-activated cell sorting. Differential activity was observed on normal liver cells and at different stages of oval cell activation, indicating potential utility for progenitor cell identification. The subdivision of liver cells using these tools should facilitate the study of the biology of ductal and periductal hepatic cell types, including progenitors. Conclusion A new panel of surface reactive monoclonal antibodies to support investigation of the murine oval cell response has been developed. PMID:18726953

  19. The endomembrane requirement for cell surface repair

    NASA Technical Reports Server (NTRS)

    McNeil, Paul L.; Miyake, Katsuya; Vogel, Steven S.

    2003-01-01

    The capacity to reseal a plasma membrane disruption rapidly is required for cell survival in many physiological environments. Intracellular membrane (endomembrane) is thought to play a central role in the rapid resealing response. We here directly compare the resealing response of a cell that lacks endomembrane, the red blood cell, with that of several nucleated cells possessing an abundant endomembrane compartment. RBC membrane disruptions inflicted by a mode-locked Ti:sapphire laser, even those initially smaller than hemoglobin, failed to reseal rapidly. By contrast, much larger laser-induced disruptions made in sea urchin eggs, fibroblasts, and neurons exhibited rapid, Ca(2+)-dependent resealing. We conclude that rapid resealing is not mediated by simple physiochemical mechanisms; endomembrane is required.

  20. Regional tumour glutamine supply affects chromatin and cell identity.

    PubMed

    Højfeldt, Jonas W; Helin, Kristian

    2016-09-28

    Limited perfusion of solid tumours produces a nutrient-deprived tumour core microenvironment. Low glutamine levels in the tumour core are now shown to lead to reduced levels of α-ketoglutarate and decreased histone demethylase activity, thereby promoting a less differentiated and more therapy-resistant state of the tumour cells.

  1. Regional tumour glutamine supply affects chromatin and cell identity.

    PubMed

    Højfeldt, Jonas W; Helin, Kristian

    2016-09-28

    Limited perfusion of solid tumours produces a nutrient-deprived tumour core microenvironment. Low glutamine levels in the tumour core are now shown to lead to reduced levels of α-ketoglutarate and decreased histone demethylase activity, thereby promoting a less differentiated and more therapy-resistant state of the tumour cells. PMID:27684506

  2. Nature of immobilization surface affects antibody specificity to placental alkaline phosphatase.

    PubMed

    Kumar, Mukesh; Khan, Imran; Sinha, Subrata

    2015-01-01

    Retention of native conformation of immobilized protein is essential for various applications including selection and detection of specific recombinant antibodies (scFvs). Placental alkaline phosphatase (PAP), an onco-fetal antigen expressed on the surface of several tumors, was immobilized on supermagnetic particles for selection of recombinant antibodies from a human phage display antibody library. The isolated antibodies were found to be cross-reactive to either of the isozymes of alkaline phosphatase, i.e., bone alkaline phosphatase (BAP) or intestinal alkaline phosphatase (IAP) and could not be used for tumor targeting. A specific anti-PAP monoclonal antibody H17E2 was tested for retention of specificity under these conditions. Binding of the antibody to magnetic beads conjugated IAP and BAP along with PAP and the ability of the two isozymes to inhibit its binding to PAP depicted the loss of isozyme specificity of the antibody. However, the antibody retained its specificity to PAP immobilized on polyvinyl chloride (PVC) surface. Enzyme activity was observed on both surfaces. This demonstrates that nature of immobilization may affect antigen-antibody binding in subtle ways, resulting in alteration of conformation of the epitopes. This may have consequences for determining the specificity of antibody binding for proteins that share a high degree of homology.

  3. Seismic signatures of carbonate caves affected by near-surface absorptions

    NASA Astrophysics Data System (ADS)

    Rao, Ying; Wang, Yanghua

    2015-12-01

    The near-surface absorption within a low-velocity zone generally has an exponential attenuation effect on seismic waves. But how does this absorption affect seismic signatures of karstic caves in deep carbonate reservoirs? Seismic simulation and analysis reveals that, although this near-surface absorption attenuates the wave energy of a continuous reflection, it does not alter the basic kinematic shape of bead-string reflections, a special seismic characteristic associated with carbonate caves in the Tarim Basin, China. Therefore, the bead-strings in seismic profiles can be utilized, with a great certainty, for interpreting the existence of caves within the deep carbonate reservoirs and for evaluating their pore spaces. Nevertheless, the difference between the central frequency and the peak frequency is increased along with the increment in the absorption. While the wave energy of bead-string reflections remains strong, due to the interference of seismic multiples generated by big impedance contrast between the infill materials of a cave and the surrounding carbonate rocks, the central frequency is shifted linearly with respect to the near-surface absorption. These two features can be exploited simultaneously, for a stable attenuation analysis of field seismic data.

  4. Biofilm Formation by the Fish Pathogen Flavobacterium columnare: Development and Parameters Affecting Surface Attachment

    PubMed Central

    Cai, Wenlong; De La Fuente, Leonardo

    2013-01-01

    Flavobacterium columnare is a bacterial fish pathogen that affects many freshwater species worldwide. The natural reservoir of this pathogen is unknown, but its resilience in closed aquaculture systems posits biofilm as the source of contagion for farmed fish. The objectives of this study were (i) to characterize the dynamics of biofilm formation and morphology under static and flow conditions and (ii) to evaluate the effects of temperature, pH, salinity, hardness, and carbohydrates on biofilm formation. Nineteen F. columnare strains, including representatives of all of the defined genetic groups (genomovars), were compared in this study. The structure of biofilm was characterized by light microscopy, confocal laser scanning microscopy, and scanning electron microscopy. F. columnare was able to attach to and colonize inert surfaces by producing biofilm. Surface colonization started within 6 h postinoculation, and microcolonies were observed within 24 h. Extracellular polysaccharide substances and water channels were observed in mature biofilms (24 to 48 h). A similar time course was observed when F. columnare formed biofilm in microfluidic chambers under flow conditions. The virulence potential of biofilm was confirmed by cutaneous inoculation of channel catfish fingerlings with mature biofilm. Several physicochemical parameters modulate attachment to surfaces, with the largest influence being exerted by hardness, salinity, and the presence of mannose. Maintenance of hardness and salinity values within certain ranges could prevent biofilm formation by F. columnare in aquaculture systems. PMID:23851087

  5. Iodine Affects Differentiation and Migration Process in Trophoblastic Cells.

    PubMed

    Olivo-Vidal, Zendy Evelyn; Rodríguez, Roció Coutiño; Arroyo-Helguera, Omar

    2016-02-01

    Iodine deficiency is associated with oxidative stress increase and preeclampsia during gestation, suggesting that iodine concentration plays an important role in the normal placenta physiology. The question raised is to analyze the effect of iodine deficiency on oxidative stress, viability, differentiation, and migration process and changes in the expression of differentiation and migration markers. Iodine deprivation was done using potassium perchlorate (KCLO4) to block sodium iodide symporter (NIS) transporter and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid DIDS to inhibit pendrine (PEN) transport for 3-48 h. Then trophoblast cells were treated with low iodine doses of 5-500 μM and high iodine doses of 100-5000 μM. Oxidative stress, viability, and human chorionic gonadotropin (hGC) were measured by colorimetric methods. Migration throphoblast cells were evaluated by both wound healing and Boyden chamber assays. Changes in mRNA expression were analyzed by real-time RT-PCR. Iodine deprivation induces a significant increase of reactive oxygen species (ROS), viability, and migration process vs control cells. We found a significant overregulation in the mRNA's peroxisome proliferator-activated receptor (PPAR-gamma), Snail, and matrix metalloproteinase-9 (MMP-9) mRNA's in cells deprived of iodine, as well as a down glial cell missing-1 (GCM-1) regulation, hGC, pregnancy-associated plasma protein-A (PAPP-A), and E-cadherin mRNA expression. The expression of hypoxic induction factor alpha (HIFα) mRNA does not change with iodine deprivation. In cells deprived of iodine, supplementing low iodine doses (5-500 μM) does not induce any significant changes in viability. However, ROS and migration process were decreased, although we found an increased human chorionic gonadotropin (hCG) secretion as a differentiation marker. In addition, we found that PPAR-gamma, Snail, and MPP-9 mRNAs expression are downregulated with low iodine doses, in contrast with GCM-1, PAPP

  6. Modelling cell motility and chemotaxis with evolving surface finite elements

    PubMed Central

    Elliott, Charles M.; Stinner, Björn; Venkataraman, Chandrasekhar

    2012-01-01

    We present a mathematical and a computational framework for the modelling of cell motility. The cell membrane is represented by an evolving surface, with the movement of the cell determined by the interaction of various forces that act normal to the surface. We consider external forces such as those that may arise owing to inhomogeneities in the medium and a pressure that constrains the enclosed volume, as well as internal forces that arise from the reaction of the cells' surface to stretching and bending. We also consider a protrusive force associated with a reaction–diffusion system (RDS) posed on the cell membrane, with cell polarization modelled by this surface RDS. The computational method is based on an evolving surface finite-element method. The general method can account for the large deformations that arise in cell motility and allows the simulation of cell migration in three dimensions. We illustrate applications of the proposed modelling framework and numerical method by reporting on numerical simulations of a model for eukaryotic chemotaxis and a model for the persistent movement of keratocytes in two and three space dimensions. Movies of the simulated cells can be obtained from http://homepages.warwick.ac.uk/∼maskae/CV_Warwick/Chemotaxis.html. PMID:22675164

  7. Microplicae--Specialized Surface Structure of Epithelial Cells of Wet-Surfaced Oral Mucosa.

    PubMed

    Asikainen, P; Sirviö, E; Mikkonen, J J W; Singh, S P; Schulten, E A J M; ten Bruggenkate, C M; Koistinen, A P; Kullaa, A M

    2015-01-01

    The surface structure of the superficial cells of the oral mucosa is decorated with numerous membrane ridges, termed microplicae (MPLs). The MPL structure is typical of the epithelial surfaces that are covered with protective mucus. Cell membrane MPLs are no longer seen as passive consequences of cellular activity. The interaction between MPLs and the mucins has been demonstrated, however the role of MPL structure seen on the upper surface of the oral epithelial cells is speculative. The cell surface is of potentially great significance, as it harbors many markers for refined prognosis and targets for oral mucosal diseases and cancer therapy. With these aspects in mind, we conducted the present review of the MPL structure and function in order to form the basis for further studies of MPLs of the oral epithelial cells.

  8. Human cells and cell membrane molecular models are affected in vitro by chlorpromazine.

    PubMed

    Suwalsky, Mario; Villena, Fernando; Sotomayor, Carlos P; Bolognin, Silvia; Zatta, Paolo

    2008-06-01

    This study presents evidence that chlorpromazine (CPZ) affects human cells and cell membrane molecular models. Human SH-SY5Y neuroblastoma cells incubated with 0.1 mM CPZ suffered a decrease of cell viability. On the other hand, phase contrast microscopy observations of human erythrocytes indicated that they underwent a morphological alteration as 1 microM CPZ changed their discoid normal shape to stomatocytes, and to hemolysis with 1 mM CPZ. X-ray diffraction experiments performed on dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) bilayers, classes of the major phospholipids present in the outer and inner sides of the erythrocyte membrane, respectively showed that CPZ disordered the polar head and acyl chain regions of both DMPC and DMPE, where these interactions were stronger with DMPC bilayers. Fluorescence spectroscopy on DMPC LUV at 18 degrees C confirmed these results. In fact, the assays showed that CPZ induced a significant reduction of their generalized polarization (GP) and anisotropy (r) values, indicative of enhanced disorder at the polar head and acyl chain regions of the DMPC lipid bilayer. PMID:18372093

  9. Cations in mammalian cells and chromosomes: Sample preparation protocols affect elemental abundances by SIMS

    NASA Astrophysics Data System (ADS)

    Levi-Setti, R.; Gavrilov, K. L.; Neilly, M. E.

    2006-07-01

    The focus of our current research aims at detailing and quantifying the presence of cations, primarily Ca and Mg, in mammalian cells and chromosomes throughout the different stages of the cell cycle, using our high resolution scanning ion microprobe, the UC-SIM. The 45 keV Ga + probe of this instrument, typically ˜40 nm in diameter, carries a current of 30-40 pA, appropriate for surface SIMS studies, but limited in sample erosion rate for dynamic SIMS mapping over cell-size areas, of order 100 μm × 100 μm. Practical and reliable use of this probe toward the above SIMS goals requires a careful matching of the latter factors with the physical and chemical consequences of sample preparation protocols. We examine here how the preferred sample cryo-preservation methodologies such as freeze-fracture and lyophilization affect high resolution SIMS analysis, and, from this standpoint, develop and evaluate the advantages and disadvantages of fast alternate approaches to drying frozen samples. The latter include the use of methanol, ethanol, and methanol/acetic acid fixative. Methanol-dried freeze-fractured samples preserve histological morphology and yield Ca and Mg distributions containing reliable differential dynamical information, when compared with those following lyophilization.

  10. Cadmium administration affects circulatory mononuclear cells in rats.

    PubMed

    Djokic, Jelena; Popov Aleksandrov, Aleksandra; Ninkov, Marina; Mirkov, Ivana; Zolotarevski, Lidija; Kataranovski, Dragan; Kataranovski, Milena

    2015-01-01

    Although numerous investigations have demonstrated a direct effect of cadmium (Cd) on peripheral blood mononuclear cell (PBMC) activity in humans, there is virtually no data concerning the in vivo impact of this metal on circulatory mononuclear cells. In this study, the effects of a sub-lethal Cd (1 mg/kg) dose were examined in rats 48 h following a single intraperitoneal injection. Cd treatment resulted in increased total peripheral blood leukocyte levels; however, decreases in PBMC numbers were seen. These changes coincided with an accumulation of mononuclear cells in the lungs and an increase in mononuclear cells expressing CD11b. A lack of effect of Cd on spontaneous nitric oxide (NO) production and on iNOS mRNA levels in the PBMC was also noted. Differential effects of Cd on PBMC inflammatory cytokine (IL-1β, TNFα, IL-6, IFNγ, and IL-17) gene expression and production were also seen. Specifically, except for IL-1β (levels increased), there were decreases (relative to controls) in mRNA levels for all the other cytokines examined. While there were no Cd treatment-related changes in spontaneous production of the cytokines assessed, there seemed to be a trend (p = 0.06) toward a decrease in spontaneous IL-6 release. When these harvested cells were stimulated ex vivo, there was no effect from Cd exposure on LPS-stimulated IL-1β and TNFα or on ConA-stimulated IFNγ or IL-17 production, but a decrease in IL-6 production in response to LPS was, again, noted. A preliminary study with a lower Cd dose (0.5 mg/kg) revealed some of the same outcomes noted here (mononuclear cell infiltration into lungs, increases in PBMC IL-1β mRNA levels), but differential (increased IL-17 mRNA levels) or newly detected outcomes (increased levels of IL-1α mRNA) as well. The described effects of the single in vivo exposure to Cd on PBMC might contribute to a better overall understanding of the immunomodulatory potential of this environmental contaminant.

  11. Pyocyanin facilitates extracellular DNA binding to Pseudomonas aeruginosa influencing cell surface properties and aggregation.

    PubMed

    Das, Theerthankar; Kutty, Samuel K; Kumar, Naresh; Manefield, Mike

    2013-01-01

    Pyocyanin is an electrochemically active metabolite produced by the human pathogen Pseudomonas aeruginosa. It is a recognized virulence factor and is involved in a variety of significant biological activities including gene expression, maintaining fitness of bacterial cells and biofilm formation. It is also recognized as an electron shuttle for bacterial respiration and as an antibacterial and antifungal agent. eDNA has also been demonstrated to be a major component in establishing P. aeruginosa biofilms. In this study we discovered that production of pyocyanin influences the binding of eDNA to P. aeruginosa PA14 cells, mediated through intercalation of pyocyanin with eDNA. P. aeruginosa cell surface properties including cell size (hydrodynamic diameter), hydrophobicity and attractive surface energies were influenced by eDNA in the presence of pyocyanin, affecting physico-chemical interactions and promoting aggregation. A ΔphzA-G PA14 mutant, deficient in pyocynain production, could not bind with eDNA resulting in a reduction in hydrodynamic diameter, a decrease in hydrophobicity, repulsive physico-chemical interactions and reduction in aggregation in comparison to the wildtype strain. Removal of eDNA by DNase I treatment on the PA14 wildtype strain resulted in significant reduction in aggregation, cell surface hydrophobicity and size and an increase in repulsive physico-chemical interactions, similar to the level of the ΔphzA-G mutant. The cell surface properties of the ΔphzA-G mutant were not affected by DNase I treatment. Based on these findings we propose that pyocyanin intercalation with eDNA promotes cell-to-cell interactions in P. aeruginosa cells by influencing their cell surface properties and physico-chemical interactions. PMID:23505483

  12. Roughness gradients on zirconia for rapid screening of cell-surface interactions: Fabrication, characterization and application.

    PubMed

    Flamant, Quentin; Stanciuc, Ana-Maria; Pavailler, Hugo; Sprecher, Christoph Martin; Alini, Mauro; Peroglio, Marianna; Anglada, Marc

    2016-10-01

    Roughness is one of the key parameters for successful osseointegration of dental implants. The understanding of how roughness affects cell response is thus crucial to improve implant performance. Surface gradients, which allow rapid and systematic investigations of cell-surface interactions, have the potential to facilitate this task. In this study, a novel method aiming to produce roughness gradients at the surface of zirconia using hydrofluoric acid etching was implemented. The topography was exhaustively characterized at the microscale and nanoscale by white light interferometry and atomic force microscopy, including the analysis of amplitude, spatial, hybrid, functional, and fractal parameters. A rapid screening of the influence of roughness on human mesenchymal stem cell morphology was conducted and potential correlations between roughness parameters and cell morphology were investigated. The roughness gradient induced significant changes in cell area (p < 0.001), aspect ratio (p = 0.01), and solidity (p = 0.026). Nanoroughness parameters were linearly correlated to cell solidity (p < 0.005), while microroughness parameters appeared nonlinearly correlated to cell area, highlighting the importance of multiscale optimization of implant topography to induce the desired cell response. The gradient method proposed here drastically reduces the efforts and resources necessary to study cell-surface interactions and provides results directly transferable to industry. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2502-2514, 2016. PMID:27227541

  13. How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration

    NASA Astrophysics Data System (ADS)

    Chevalier, N. R.; Gazguez, E.; Bidault, L.; Guilbert, T.; Vias, C.; Vian, E.; Watanabe, Y.; Muller, L.; Germain, S.; Bondurand, N.; Dufour, S.; Fleury, V.

    2016-02-01

    Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development.

  14. Matrix metalloproteinase inhibition negatively affects muscle stem cell behavior.

    PubMed

    Bellayr, Ian; Holden, Kyle; Mu, Xiaodong; Pan, Haiying; Li, Yong

    2013-01-01

    Skeletal muscle is a large and complex system that is crucial for structural support, movement and function. When injured, the repair of skeletal muscle undergoes three phases: inflammation and degeneration, regeneration and fibrosis formation in severe injuries. During fibrosis formation, muscle healing is impaired because of the accumulation of excess collagen. A group of zinc-dependent endopeptidases that have been found to aid in the repair of skeletal muscle are matrix metalloproteinases (MMPs). MMPs are able to assist in tissue remodeling through the regulation of extracellular matrix (ECM) components, as well as contributing to cell migration, proliferation, differentiation and angiogenesis. In the present study, the effect of GM6001, a broad-spectrum MMP inhibitor, on muscle-derived stem cells (MDSCs) is investigated. We find that MMP inhibition negatively impacts skeletal muscle healing by impairing MDSCs in migratory and multiple differentiation abilities. These results indicate that MMP signaling plays an essential role in the wound healing of muscle tissue because their inhibition is detrimental to stem cells residing in skeletal muscle. PMID:23329998

  15. How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration

    PubMed Central

    Chevalier, N.R.; Gazguez, E.; Bidault, L.; Guilbert, T.; Vias, C.; Vian, E.; Watanabe, Y.; Muller, L.; Germain, S.; Bondurand, N.; Dufour, S.; Fleury, V.

    2016-01-01

    Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development. PMID:26887292

  16. Elucidating Sources and Factors Affecting Delivery of Nitrogen to Surface Waters of New York State

    NASA Astrophysics Data System (ADS)

    Golden, H. E.; Boyer, E. W.; Burns, D. A.; Elliott, E.; Kendall, C.; Butler, T.

    2005-12-01

    Rapid changes in power generation, transportation, and agriculture have appreciably altered nitrogen (N) cycling at regional scales, increasing N inputs to landscapes and surface waters. Numerous studies have linked this surplus N to a host of concerns, including eutrophication and violations in drinking water standards. Inputs of N nation-wide have increased during recent decades, primarily from the production and use of fertilizers, the planting of N-fixing crops, and the combustion of fossil fuels. The role of atmospheric N sources is of particular concern in New York, as rates of atmospheric N deposition in the northeast are among the highest in the nation. Our work aims to quantify nitrogen sources and fate in watersheds throughout the state. Further, we intend to elucidate factors controlling the retention and release of N to surface waters. We quantify nitrogen inputs through both measurement data (e.g., from wet and dry atmospheric deposition, precipitation, streamflow, water quality, and isotopic tracers) and from synoptic spatial databases (e.g., of terrain, land use, and fertilizer inputs). We present preliminary results from large catchments in contrasting spatial settings across the state (different land use configurations and atmospheric deposition gradients), illustrating the contribution of nitrogen sources to each region and factors affecting delivery to surface waters. Further, we present 30 years of temporal data from a large watershed (Fall Creek) in the Finger Lakes region of the state to demonstrate how hydrological and biogeochemical factors, over seasons and under varying hydrological regimes, combine to control N dynamics in surface waters. Our collective work provides information that is necessary to develop sound strategies for understanding and managing nutrients at regional scales.

  17. Modulated surface nanostructures for enhanced light trapping and reduced surface reflection of crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    Tayagaki, Takeshi; Hoshi, Yusuke; Hirai, Yuji; Matsuo, Yasutaka; Usami, Noritaka

    2016-05-01

    We demonstrated the fabrication of modulated surface nanostructures as a new surface texture design for thin wafer solar cells. Using a combination of conventional alkali etching and colloidal lithography, we fabricated surface textures with micrometer and nanometre scales on a Si substrate. These modulated surface nanostructures exhibit reduced surface reflection in a broad spectral range, compared with conventional micrometer textures. We investigated optical absorption using a rigorous coupled wave analysis simulation, which revealed a significant reduction in surface reflection over a broad spectral range and efficient light trapping (comparable to that of conventional micrometer-scale textures) for the modulated nanostructures. We found that the modulated surface nanostructures have a high potential of improving the performance of thin wafer crystalline Si solar cells.

  18. Biodegradable microgrooved polymeric surfaces obtained by photolithography for skeletal muscle cell orientation and myotube development.

    PubMed

    Altomare, L; Gadegaard, N; Visai, L; Tanzi, M C; Farè, S

    2010-06-01

    During tissue formation, skeletal muscle precursor cells fuse together to form multinucleated myotubes. To understand this mechanism, in vitro systems promoting cell alignment need to be developed; for this purpose, micrometer-scale features obtained on substrate surfaces by photolithography can be used to control and affect cell behaviour. This work was aimed at investigating how differently microgrooved polymeric surfaces can affect myoblast alignment, fusion and myotube formation in vitro. Microgrooved polymeric films were obtained by solvent casting of a biodegradable poly-l-lactide/trimethylene carbonate copolymer (PLLA-TMC) onto microgrooved silicon wafers with different groove widths (5, 10, 25, 50, 100microm) and depths (0.5, 1, 2.5, 5microm), obtained by a standard photolithographic technique. The surface topography of wafers and films was evaluated by scanning electron microscopy. Cell assays were performed using C2C12 cells and myotube formation was analysed by immunofluorescence assays. Cell alignment and circularity were also evaluated using ImageJ software. The obtained results confirm the ability of microgrooved surfaces to influence myotube formation and alignment; in addition, they represent a novel further improvement to the comprehension of best features to be used. The most encouraging results were observed in the case of microstructured PLLA-TMC films with grooves of 2.5 and 1microm depth, presenting, in particular, a groove width of 50 and 25microm.

  19. Contact inhibition of phagocytosis in epithelial sheets: alterations of cell surface properties induced by cell-cell contacts.

    PubMed Central

    Vasiliev, J M; Gelfand, I M; Domnina, L V; Zacharova, O S; Ljubimov, A V

    1975-01-01

    Contact inhibition of phagocytosis was found to be characteristic for epithelial sheets formed in cultures by several cell types: normal and transformed mouse kidney cells, and differentiated mouse hepatoma cells. In these sheets most central cells surrounded by other cells had very low phagocytic activity. In contrast, marginal cells having a free edge were able to perform an active phagocytosis. Contact inhibition of phagocytosis was absent in dense cultures of mouse embryo fibroblasts and in cultures of anaplastic mouse hepatoma 22a. The upper surface of epithelial sheets was nonadhesive for prelabeled epithelial cells and fibroblasts. In contrast, the upper surface of dense cultures of mouse fibroblasts was adhesive for these cells. These and other data strengthen the suggestion that contact inhibition of phagocytosis is a result of different adhesiveness of the upper cell surface and of the surfaces near the free edge. Agents inhibiting cell surface movements at the free edges of marginal epithelial cells (cytochalasin, azide, sorbitol, low temperature) prevented adhesion of particles to these edges. Possibly, the surface of actively moving cytoplasmic processes is the only cell part that has adhesive properties necessary for the formation of attachments with other cellular and noncellular surfaces. In epithelial sheets, in contrast to fibroblast cultures, Colcemid did not activate movements of immobile contacting cell edges. These results indicate that mechanisms of contact immobilization of cell surface may be different in epithelium and fibroblasts. Firm contacts formed between epithelial cells are sufficient for stable immobilization of the surface; additional stabilization of the surface by microtubules is not essential. Fibroblasts do not form firm contacts and the Colcemid-sensitive stabilization process is essential for maintenance of the immobile state of their surfaces. Differences in the stability of cell surface immobilization produced by cell-cell

  20. Emergence of an Apical Epithelial Cell Surface In Vivo.

    PubMed

    Sedzinski, Jakub; Hannezo, Edouard; Tu, Fan; Biro, Maté; Wallingford, John B

    2016-01-11

    Epithelial sheets are crucial components of all metazoan animals, enclosing organs and protecting the animal from its environment. Epithelial homeostasis poses unique challenges, as addition of new cells and loss of old cells must be achieved without disrupting the fluid-tight barrier and apicobasal polarity of the epithelium. Several studies have identified cell biological mechanisms underlying extrusion of cells from epithelia, but far less is known of the converse mechanism by which new cells are added. Here, we combine molecular, pharmacological, and laser-dissection experiments with theoretical modeling to characterize forces driving emergence of an apical surface as single nascent cells are added to a vertebrate epithelium in vivo. We find that this process involves the interplay between cell-autonomous actin-generated pushing forces in the emerging cell and mechanical properties of neighboring cells. Our findings define the forces driving this cell behavior, contributing to a more comprehensive understanding of epithelial homeostasis.

  1. A requirement for trypsin-sensitive cell-surface components for cell-cell interactions of embryonic neural retina cells

    PubMed Central

    McClay, DR; Godding, LR; Fransen, ME

    1977-01-01

    A quantitative assay was used to measure the rate of collection of a population of embryonic neural retina cells to the surface of cell aggregates. The rate of collection of freshly trysinized cells was limited in the initial stages by the rate of replacement of trypsin-sensitive cell- surface components. When cells were preincubated, or "recovered," and then added to cell aggregates, collection occurred at a linear rate and was independent of protein and glycoprotein synthesis. The adhesion of recovered cells was temperature and energy dependent, and was reversibly inhibited by cytochalasin B. Colchicine had little effect on collection of recovered cells. Antiserum directed against recovered cell membranes was shown to bind to recovered cells by indirect immunofluorescence. The antiserum also was shown to inhibit collection of recovered cells to aggregates, suggesting that at least some of the antigens identified might be involved in the adhesion process. The inhibitory effect of the antiserum was dose dependent . Freshly trypsinized cells absorbed neither the immunofluorescence activity nor the adhesion-inhibiting activity. Recovered cells absorbed away both activities. In specificity studies, dorsal neural retina cells adhered to aggregates of ventral optic tectum in preference to aggregates of dorsal optic tectum. The adhesive specificity of the dorsal retina cells was less sensitive to trypsin than the adhesive specificity of ventral retina cells which adhered preferentially to dorsal tectal aggregates only after a period of recovery. PMID:562349

  2. The cell surface environment for pathogen recognition and entry

    PubMed Central

    Stow, Jennifer L; Condon, Nicholas D

    2016-01-01

    The surface of mammalian cells offers an interface between the cell interior and its surrounding milieu. As part of the innate immune system, macrophages have cell surface features optimised for probing and sampling as they patrol our tissues for pathogens, debris or dead cells. Their highly dynamic and constantly moving cell surface has extensions such as lamellipodia, filopodia and dorsal ruffles that help detect pathogens. Dorsal ruffles give rise to macropinosomes for rapid, high volume non-selective fluid sampling, receptor internalisation and plasma membrane turnover. Ruffles can also generate phagocytic cups for the receptor-mediated uptake of pathogens or particles. The membrane lipids, actin cytoskeleton, receptors and signalling proteins that constitute these cell surface domains are discussed. Although the cell surface is designed to counteract pathogens, many bacteria, viruses and other pathogens have evolved to circumvent or hijack these cell structures and their underlying machinery for entry and survival. Nevertheless, these features offer important potential for developing vaccines, drugs and preventative measures to help fight infection. PMID:27195114

  3. Cell surface engineering of industrial microorganisms for biorefining applications.

    PubMed

    Tanaka, Tsutomu; Kondo, Akihiko

    2015-11-15

    In order to decrease carbon emissions and negative environmental impacts of various pollutants, biofuel/biochemical production should be promoted for replacing fossil-based industrial processes. Utilization of abundant lignocellulosic biomass as a feedstock has recently become an attractive option. In this review, we focus on recent efforts of cell surface display using industrial microorganisms such as Escherichia coli and yeast. Cell surface display is used primarily for endowing cellulolytic activity on the host cells, and enables direct fermentation to generate useful fuels and chemicals from lignocellulosic biomass. Cell surface display systems are systematically summarized, and the drawbacks/perspectives as well as successful application of surface display for industrial biotechnology are discussed.

  4. Cell surface engineering of industrial microorganisms for biorefining applications.

    PubMed

    Tanaka, Tsutomu; Kondo, Akihiko

    2015-11-15

    In order to decrease carbon emissions and negative environmental impacts of various pollutants, biofuel/biochemical production should be promoted for replacing fossil-based industrial processes. Utilization of abundant lignocellulosic biomass as a feedstock has recently become an attractive option. In this review, we focus on recent efforts of cell surface display using industrial microorganisms such as Escherichia coli and yeast. Cell surface display is used primarily for endowing cellulolytic activity on the host cells, and enables direct fermentation to generate useful fuels and chemicals from lignocellulosic biomass. Cell surface display systems are systematically summarized, and the drawbacks/perspectives as well as successful application of surface display for industrial biotechnology are discussed. PMID:26070720

  5. Epoxyeicosatrienoic Acids Affect Electrolyte Transport in Renal Tubular Epithelial Cells: Dependence on Cyclooxygenase and Cell Polarity

    PubMed Central

    Nüsing, Rolf M.; Schweer, Horst; Fleming, Ingrid; Zeldin, Darryl C.; Wegmann, Markus

    2007-01-01

    We investigated the effects of epoxyeicosatrienoic acids (EETs) on ion transport in the polarized renal distal tubular cell line, MDCK C7. Of the four EET regioisomers (5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET) studied, only apical, but not basolateral, application of 5,6-EET increased short circuit current (Isc) with kinetics similar to those of arachidonic acid. The ion transport was blocked by preincubation with the cyclooxygenase inhibitor indomethacin or with the chloride channel blocker NPPB. Further, both a Cl−-free bath solution and the Ca2+ antagonist verapamil blocked 5,6-EET-induced ion transport. Although the presence of the PGE2 receptors EP2, EP3, and EP4 was demonstrated, apically added PGE2 was ineffective and basolaterally added PGE2 caused a different kinetics in ion transport compared to 5,6-EET. Moreover, PGE2 sythesis in MDCK C7 cells was unaffected by 5,6-EET treatment. GC/MS/MS analysis of cell supernatants revealed the presence of the biologically inactive 5,6-dihydroxy-PGE1 in 5,6-EET-treated cells, but not in control cells. Indomethacin suppressed the formation of 5,6-dihydroxy-PGE1. 5,6-epoxy-PGE1 the precursor of 5,6-dihydroxy-PGE1, caused a similar ion transport as 5,6-EET. Cytochrome P450 enzymes homolog to human CYP2C8, CYP2C9, and CYP2J2 protein were detected immunologically in the MDCK C7 cells. Our findings suggest that 5,6-EET affects Cl-transport in renal distal tubular cells independent of PGE2 but by a mechanism, dependent on its conversion to 5,6-epoxy-PGE1 by cyclooxygenase. We suggest a role for this P450 epoxygenase product in the regulation of electrolyte transport, especially as a saluretic compound acting from the luminal side of tubular cells in the mammalian kidney. PMID:17494091

  6. The novel herbicide oxaziclomefone inhibits cell expansion in maize cell cultures without affecting turgor pressure or wall acidification.

    PubMed

    O'Looney, Nichola; Fry, Stephen C

    2005-11-01

    Oxaziclomefone [OAC; IUPAC name 3-(1-(3,5-dichlorophenyl)-1-methylethyl)-3,4-dihydro-6-methyl-5-phenyl-2H-1,3-oxazin-4-one] is a new herbicide that inhibits cell expansion in grass roots. Its effects on cell cultures and mode of action were unknown. In principle, cell expansion could be inhibited by a decrease in either turgor pressure or wall extensibility. Cell expansion was estimated as settled cell volume; cell division was estimated by cell counting. Membrane permeability to water was measured by a novel method involving simultaneous assay of the efflux of (3)H(2)O and [(14)C]mannitol from a 'bed' of cultured cells. Osmotic potential was measured by depression of freezing point. OAC inhibited cell expansion in cultures of maize (Zea mays), spinach (Spinacia oleracea) and rose (Rosa sp.), with an ID(50) of 5, 30 and 250 nm, respectively. In maize cultures, OAC did not affect cell division for the first 40 h. It did not affect the osmotic potential of cell sap or culture medium, nor did it impede water transport across cell membranes. It did not affect cells' ability to acidify the apoplast (medium), which may be necessary for 'acid growth'. As OAC did not diminish turgor pressure, its ability to inhibit cell expansion must depend on changes in wall extensibility. It could be a valuable tool for studies on cell expansion.

  7. Evidence of cell surface iron speciation of acidophilic iron-oxidizing microorganisms in indirect bioleaching process.

    PubMed

    Nie, Zhen-yuan; Liu, Hong-chang; Xia, Jin-lan; Yang, Yi; Zhen, Xiang-jun; Zhang, Li-Juan; Qiu, Guan-zhou

    2016-02-01

    While indirect model has been widely accepted in bioleaching, but the evidence of cell surface iron speciation has not been reported. In the present work the iron speciation on the cell surfaces of four typically acidophilic iron-oxidizing microorganism (mesophilic Acidithiobacillus ferrooxidans ATCC 23270, moderately thermophilic Leptospirillum ferriphilum YSK and Sulfobacillus thermosulfidooxidans St, and extremely thermophilic Acidianus manzaensis YN25) grown on different energy substrates (chalcopyrite, pyrite, ferrous sulfate and elemental sulfur (S(0))) were studied in situ firstly by using synchrotron-based micro- X-ray fluorescence analysis and X-ray absorption near-edge structure spectroscopy. Results showed that the cells grown on iron-containing substrates had apparently higher surface iron content than the cells grown on S(0). Both ferrous iron and ferric iron were detected on the cell surface of all tested AIOMs, and the Fe(II)/Fe(III) ratios of the same microorganism were affected by different energy substrates. The iron distribution and bonding state of single cell of A. manzaensis were then studied in situ by scanning transmission soft X-ray microscopy based on dual-energy contrast analysis and stack analysis. Results showed that the iron species distributed evenly on the cell surface and bonded with amino, carboxyl and hydroxyl groups.

  8. Potato Snakin-1 Gene Silencing Affects Cell Division, Primary Metabolism, and Cell Wall Composition1[W

    PubMed Central

    Nahirñak, Vanesa; Almasia, Natalia Inés; Fernandez, Paula Virginia; Hopp, Horacio Esteban; Estevez, José Manuel; Carrari, Fernando; Vazquez-Rovere, Cecilia

    2012-01-01

    Snakin-1 (SN1) is an antimicrobial cysteine-rich peptide isolated from potato (Solanum tuberosum) that was classified as a member of the Snakin/Gibberellic Acid Stimulated in Arabidopsis protein family. In this work, a transgenic approach was used to study the role of SN1 in planta. Even when overexpressing SN1, potato lines did not show remarkable morphological differences from the wild type; SN1 silencing resulted in reduced height, which was accompanied by an overall reduction in leaf size and severe alterations of leaf shape. Analysis of the adaxial epidermis of mature leaves revealed that silenced lines had 70% to 90% increases in mean cell size with respect to wild-type leaves. Consequently, the number of epidermal cells was significantly reduced in these lines. Confocal microscopy analysis after agroinfiltration of Nicotiana benthamiana leaves showed that SN1-green fluorescent protein fusion protein was localized in plasma membrane, and bimolecular fluorescence complementation assays revealed that SN1 self-interacted in vivo. We further focused our study on leaf metabolism by applying a combination of gas chromatography coupled to mass spectrometry, Fourier transform infrared spectroscopy, and spectrophotometric techniques. These targeted analyses allowed a detailed examination of the changes occurring in 46 intermediate compounds from primary metabolic pathways and in seven cell wall constituents. We demonstrated that SN1 silencing affects cell division, leaf primary metabolism, and cell wall composition in potato plants, suggesting that SN1 has additional roles in growth and development beyond its previously assigned role in plant defense. PMID:22080603

  9. Standing surface acoustic wave (SSAW)-based cell washing

    PubMed Central

    Li, Sixing; Ding, Xiaoyun; Mao, Zhangming; Chen, Yuchao; Nama, Nitesh; Guo, Feng; Li, Peng; Wang, Lin; Cameron, Craig E.; Huang, Tony Jun

    2014-01-01

    Cell/bead washing is an indispensable sample preparation procedure used in various cell studies and analytical processes. In this article, we report a standing surface acoustic wave (SSAW)-based microfluidic device for cell and bead washing in a continuous flow. In our approach, the acoustic radiation force generated in a SSAW field is utilized to actively extract cells or beads from their original medium. A unique configuration of tilted-angle standing surface acoustic wave (taSSAW) is employed in our device, enabling us to wash beads with >98% recovery rate and >97% washing efficiency. We also demonstrate the functionality of our device by preparing high-purity (>97%) white blood cells from lysed blood samples through cell washing. Our SSAW-based cell/bead washing device has the advantages of label-free manipulation, simplicity, high biocompatibility, high recovery rate, and high washing efficiency. It can be useful for many lab-on-a-chip applications. PMID:25372273

  10. Fusion and metabolism of plant cells as affected by microgravity.

    PubMed

    Hampp, R; Hoffmann, E; Schönherr, K; Johann, P; De Filippis, L

    1997-01-01

    Plant cell protoplasts derived from leaf tissue of two different tobacco species (Nicotiana tabacum., N. rustica L.) were exposed to short-term (sounding rocket experiments) and long-term (spacelab) microgravity environments in order to study both (electro) cell fusion and cell metabolism during early and later stages of tissue regeneration. The period of exposure to microgravity varied from 10 min (sounding rocket) to 10 d (space shuttle). The process of electro fusion of protoplasts was improved under conditions of microgravity: the time needed to establish close membrane contact between protoplasts (alignment time) was reduced (5 as compared to 15 s under 1 g) and numbers of fusion products between protoplasts of different specific density were increased by a factor of about 10. In addition, viability of fusion products, as shown by the ability to form callus, increased from about 60% to more than 90%. Regenerated fusion products obtained from both sounding-rocket and spacelab experiments showed a wide range of intermediate properties between the two parental plants. This was verified by isozyme analysis and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). In order to address potential metabolic responses, more general markers such as the overall energy state (ATP/ADP ratio), the redox charge of the diphosphopyridine nucleotide system (NADH/NAD ratio), and the pool size of fructose-2,6-bisphosphate (Fru 2,6 bisp), a regulator of the balance between glycolysis and gluconeogenesis, were determined. Responses of these parameters were different with regard to short-term and long-term exposure. Shortly after transition to reduced gravitation (sounding rocket) ratios of ATP/ADP exhibited strong fluctuation while the pool size of NAD decreased (indicating an increased NADH/NAD ratio) and that of Fru 2,6 bisp increased. As similar changes can be observed under stress conditions, this response is probably indicative of a metabolic stress

  11. Simultaneous interaction of bacteria and tissue cells with photocatalytically activated, anodized titanium surfaces.

    PubMed

    Yue, Chongxia; Kuijer, Roel; Kaper, Hans J; van der Mei, Henny C; Busscher, Henk J

    2014-03-01

    Photocatalytic-activation of anodized TiO2-surfaces has been demonstrated to yield antibacterial and tissue integrating effects, but effects on simultaneous growth of tissue cells and bacteria in co-culture have never been studied. Moreover, it is unknown how human-bone-marrow-mesenchymal-stem (hBMMS) cells, laying the groundwork for integration of titanium implants in bone, respond to photocatalytic activation of anodized TiO2-surfaces. Photocatalytically-activated, anodized titanium and titanium-alloy surfaces achieved 99.99% killing of adhering Staphylococcus epidermidis and Staphylococcus aureus, an effect that lasted for 30 days of storage in air. Surface coverage by osteoblasts was not affected by photocatalytic activation of anodized TiO2-surfaces. Co-cultures of osteoblasts with contaminating S. epidermidis however, enhanced surface coverage on photocatalytically-activated, anodized titanium-alloy surfaces. hBMMS cells grew less on photocatalytically-activated, anodized titanium surfaces, while not at all on photocatalytically-activated, anodized titanium-alloy surfaces and did not survive the presence of contaminating staphylococci. This reduced surface coverage by hBMMS cells disappeared when photocatalytically-activated, anodized titanium-alloy surfaces were exposed to buffer for 60 min, both in absence or presence of contaminating S. aureus. Consequently, it is concluded that photocatalytically-activated, anodized titanium and titanium-alloy surfaces will effectively kill peri-operatively introduced staphylococci contaminating an implant surface and constitute an effective means for antibiotic prophylaxis in cementless fixation of orthopaedic hardware.

  12. Surface plasmonic effects on organic solar cells.

    PubMed

    Uddin, Ashraf; Yang, Xiaohan

    2014-02-01

    Most high-performance organic photovoltaic (OPV) devices reported in the literature have been fabricated using the bulk heterojunction (BHJ) concept. Typically, the optimum thickness of the active layer for an OPV device is around 100 nm, or possibly less; such a thin layer can lead to low absorption of light. A thicker layer, however, inevitably increases the device resistance, due to the low carrier mobilities and short exciton diffusion lengths in organic materials. This situation imposes a trade-off between light absorption and charge transport efficiencies in OPV devices, motivating the development of a variety of light-trapping techniques. Metallic nanoparticles (NPs) such as Ag, Au, etc. and other metallic nanostructures are potential candidates for improving the light absorption due to the localized surface plasmon resonance (LSPR). LSPR contributes to the significant enhancement of local electromagnetic fields and improves the optical properties of the nanostructure devices. The excitation of LSPR is achieved when the frequency of the incident light matches its resonance peak, resulting in unique optical properties; selective light extinction as well as local enhancement of electromagnetic fields near the surface of metallic NPs. The resonance peak of LSPR depends strongly on the size, shape, and the dielectric environment of the metallic NPs. In this review article, progress on plasmonic enhanced OPV device performance is examined. The concepts of surface plasmonics for OPV devices, suitable plasmonic materials, location, optimum size and concentration of NP materials within the device are explored.

  13. Enhancement of Biological Reactions on Cell Surfaces via Macromolecular Crowding

    PubMed Central

    Chapanian, Rafi; Kwan, David H.; Constantinescu, Iren; Shaikh, Fathima A.; Rossi, Nicholas A.A.; Withers, Stephen G.; Kizhakkedathu, Jayachandran N.

    2016-01-01

    The reaction of macromolecules such as enzymes and antibodies with cell surfaces is often an inefficient process, requiring large amounts of expensive reagent. Here we report a general method based on macromolecular crowding with a range of neutral polymers to enhance such reactions, using red blood cells (RBCs) as a model system. Rates of conversion of Type A and B red blood cells to universal O type by removal of antigenic carbohydrates with selective glycosidases are increased up to 400-fold in the presence of crowders. Similar enhancements are seen for antibody binding. We further explore the factors underlying these enhancements using confocal microscopy and fluorescent recovery after bleaching (FRAP) techniques with various fluorescent protein fusion partners. Increased cell-surface concentration due to volume exclusion, along with two-dimensionally confined diffusion of enzymes close to the cell surface, appear to be the major contributing factors. PMID:25140641

  14. Recent Insights into Cell Surface Heparan Sulphate Proteoglycans and Cancer.

    PubMed

    Couchman, John R; Multhaupt, Hinke; Sanderson, Ralph D

    2016-01-01

    A small group of cell surface receptors are proteoglycans, possessing a core protein with one or more covalently attached glycosaminoglycan chains. They are virtually ubiquitous and their chains are major sites at which protein ligands of many types interact. These proteoglycans can signal and regulate important cell processes, such as adhesion, migration, proliferation, and differentiation. Since many protein ligands, such as growth factors, morphogens, and cytokines, are also implicated in tumour progression, it is increasingly apparent that cell surface proteoglycans impact tumour cell behaviour. Here, we review some recent advances, emphasising that many tumour-related functions of proteoglycans are revealed only after their modification in processes subsequent to synthesis and export to the cell surface. These include enzymes that modify heparan sulphate structure, recycling of whole or fragmented proteoglycans into exosomes that can be paracrine effectors or biomarkers, and lateral interactions between some proteoglycans and calcium channels that impact the actin cytoskeleton. PMID:27408707

  15. Recent Insights into Cell Surface Heparan Sulphate Proteoglycans and Cancer

    PubMed Central

    Couchman, John R; Multhaupt, Hinke; Sanderson, Ralph D.

    2016-01-01

    A small group of cell surface receptors are proteoglycans, possessing a core protein with one or more covalently attached glycosaminoglycan chains. They are virtually ubiquitous and their chains are major sites at which protein ligands of many types interact. These proteoglycans can signal and regulate important cell processes, such as adhesion, migration, proliferation, and differentiation. Since many protein ligands, such as growth factors, morphogens, and cytokines, are also implicated in tumour progression, it is increasingly apparent that cell surface proteoglycans impact tumour cell behaviour. Here, we review some recent advances, emphasising that many tumour-related functions of proteoglycans are revealed only after their modification in processes subsequent to synthesis and export to the cell surface. These include enzymes that modify heparan sulphate structure, recycling of whole or fragmented proteoglycans into exosomes that can be paracrine effectors or biomarkers, and lateral interactions between some proteoglycans and calcium channels that impact the actin cytoskeleton. PMID:27408707

  16. Analysis of cell surface properties using derivatized agarose beads.

    PubMed

    Salbilla, B A; Vaghefi, H; Chhabra, P; Hall, G; Brown, D; Sadoughi, F; Francisco, E; Attas, L; Walker, S L; Nguyen, B N; Oppenheimer, S B

    1999-07-01

    An assay has been developed to analyse cell surface properties using agarose beads derivatized with amino acids, sugars, proteins, and other molecules. The assay is simple and rapid and is useful to identify new cell surface markers. Various species and strains of yeast, paramecium, and Euglena were tested for their ability to bind to over 100 types of derivatized beads. A variety of specificity studies were performed in order to understand the nature of cell-bead binding. Our results indicate that cell-bead binding is often specific enough to distinguish between configurational isomers and spacer sizes and can be blocked by addition of specific molecules to the incubation medium. In some cases, different species or strains differed only by their binding to a single bead type. This simple and rapid assay may help to uncover new cell surface receptors and may lead to the development of clinically useful compounds for therapeutic applications.

  17. Streptomycin favors biofilm formation by altering cell surface properties.

    PubMed

    Kumar, Amit; Ting, Yen-Peng

    2016-10-01

    Studies have shown that external stress induces biofilm formation, but the underlying details are not clearly understood. This study investigates the changes in cell surface properties leading to increase in biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa in the presence of streptomycin. Bacterial attachment in the presence and absence of streptomycin was quantified by fluorescence spectroscopy. In addition, cell surface charge and contact angle were measured and the free energy barrier for attachment was modeled using extended Derjaguin-Landau-Verwey-Overbeek (xDLVO) theory. Peptides from bacterial cell surface were shaved by protease treatment and identified with ultra-performance liquid chromatography (UPLC)-QTOF and a homology search program SPIDER. Biofilm formation increased significantly in the presence of streptomycin (10 mg/L) in the culture. Bacterial cell surface charge reduced, and hydrophobicity increased leading to a net decrease in the free energy barrier for attachment. Extracellular matrix-binding protein was positively regulated in S. aureus under stress, indicating stronger interaction between bacterial cells and solid surface. In addition, several other proteins including biofilm regulatory proteins, multidrug efflux pumps, transporters, signaling proteins, and virulence factors were differentially expressed on bacterial cell surface, which is indicative of a strong stress response by bacteria to streptomycin treatment. PMID:27568380

  18. A Method of Targeted Cell Isolation via Glass Surface Functionalization.

    PubMed

    Ansari, Ali; Patel, Reema; Schultheis, Kinsey; Naumovski, Vesna; Imoukhuede, P I

    2016-01-01

    One of the limiting factors to the adoption and advancement of personalized medicine is the inability to develop diagnostic tools to probe individual nuances in expression from patient to patient. Current methodologies that try to separate cells to fill this niche result in disruption of physiological expression, making the separation technique useless as a diagnostic tool. In this protocol, we describe the functionalization and optimization of a surface for the cellular capture and release. This functionalized surface integrates biotinylated antibodies with a glass surface functionalized with an aminosilane (APTES), desthiobiotin and streptavidin. Cell release is facilitated through the introduction of biotin, allowing the recollection and purification of cells captured by the surface. This release is done through the targeting of the secondary moiety desthiobiotin, which results in a much more gentle release paradigm. This reduction in harsh reagents and shear forces reduces changes in cellular expression. The functionalized surface captures up to 80% of cells in a single cell mixture and has demonstrated 50% capture in a dual-cell mixture. Applications of this technology to xenografts and cancer separation studies are investigated. Quantification techniques for surface verification such as plate reader and ImageJ analyses are described as well. PMID:27684992

  19. Oxide modified air electrode surface for high temperature electrochemical cells

    DOEpatents

    Singh, Prabhakar; Ruka, Roswell J.

    1992-01-01

    An electrochemical cell is made having a porous cermet electrode (16) and a porous lanthanum manganite electrode (14), with solid oxide electrolyte (15) between them, where the lanthanum manganite surface next to the electrolyte contains a thin discontinuous layer of high surface area cerium oxide and/or praseodymium oxide, preferably as discrete particles (30) in contact with the air electrode and electrolyte.

  20. Nanometer polymer surface features: the influence on surface energy, protein adsorption and endothelial cell adhesion

    NASA Astrophysics Data System (ADS)

    Carpenter, Joseph; Khang, Dongwoo; Webster, Thomas J.

    2008-12-01

    Current small diameter (<5 mm) synthetic vascular graft materials exhibit poor long-term patency due to thrombosis and intimal hyperplasia. Tissue engineered solutions have yielded functional vascular tissue, but some require an eight-week in vitro culture period prior to implantation—too long for immediate clinical bedside applications. Previous in vitro studies have shown that nanostructured poly(lactic-co-glycolic acid) (PLGA) surfaces elevated endothelial cell adhesion, proliferation, and extracellular matrix synthesis when compared to nanosmooth surfaces. Nonetheless, these studies failed to address the importance of lateral and vertical surface feature dimensionality coupled with surface free energy; nor did such studies elicit an optimum specific surface feature size for promoting endothelial cell adhesion. In this study, a series of highly ordered nanometer to submicron structured PLGA surfaces of identical chemistry were created using a technique employing polystyrene nanobeads and poly(dimethylsiloxane) (PDMS) molds. Results demonstrated increased endothelial cell adhesion on PLGA surfaces with vertical surface features of size less than 18.87 nm but greater than 0 nm due to increased surface energy and subsequently protein (fibronectin and collagen type IV) adsorption. Furthermore, this study provided evidence that the vertical dimension of nanometer surface features, rather than the lateral dimension, is largely responsible for these increases. In this manner, this study provides key design parameters that may promote vascular graft efficacy.

  1. Evaluating the Potential for Landfill Leachate to Affect Surface and Ground Water Quality

    NASA Astrophysics Data System (ADS)

    Pederson, D. T.; Towerton, M. M.

    2005-12-01

    As precipitation percolates through waste in a landfill, contaminants associated with waste dissolve, forming leachate. Landfill leachate has the potential to pollute ground and surface water if not properly managed. Predicting chemical parameters and quantity of leachate generated is vital not only to understand how ground and surface water may be affected by landfill leachate, but also useful in determining when leachate components are in compliance with US Environment Protection Agency's drinking water standards. The Bluff Road landfill in Lincoln, Nebraska provided sixteen years of data from active land filling operation. Data included quarterly chemical analyses of leachate and quantity of leachate generated. Linear regression between chemical parameters and time determine if the long-term concentration trend is increasing, decreasing, or stable. Predictions of quantity of leachate generated were made through application of a published model. Long-term trends for inorganic macro components appear to mirror each other indicating that physical processes dominate over chemical processes. Heavy metal concentrations show a decline with time for all parameters except for iron, cadmium, and copper which is in agreement with published studies. Modeling the quantity of leachate generated was successful in duplicating the general trend of measured values, but was not accurate in matching quantitative values.

  2. Expanding the diversity of unnatural cell surface sialic acids

    SciTech Connect

    Luchansky, Sarah J.; Goon, Scarlett; Bertozzi, Carolyn R.

    2003-10-30

    Novel chemical reactivity can be introduced onto cell surfaces through metabolic oligosaccharide engineering. This technique exploits the substrate promiscuity of cellular biosynthetic enzymes to deliver unnatural monosaccharides bearing bioorthogonal functional groups into cellular glycans. For example, derivatives of N-acetylmannosamine (ManNAc) are converted by the cellular biosynthetic machinery into the corresponding sialic acids and subsequently delivered to the cell surface in the form of sialoglycoconjugates. Analogs of N-acetylglucosamine (GlcNAc) and N-acetylgalactosamine (GalNAc) are also metabolized and incorporated into cell surface glycans, likely through the sialic acid and GalNAc salvage pathways, respectively. Furthermore, GlcNAc analogs can be incorporated into nucleocytoplasmic proteins in place of {beta}-O-GlcNAc residues. These pathways have been exploited to integrate unique electrophiles such as ketones and azides into the target glycoconjugate class. These functional groups can be further elaborated in a chemoselective fashion by condensation with hydrazides and by Staudinger ligation, respectively, thereby introducing detectable probes onto the cell. In conclusion, sialic acid derivatives are efficient vehicles for delivery of bulky functional groups to cell surfaces and masking of their hydroxyl groups improves their cellular uptake and utilization. Furthermore, the successful introduction of photoactivatable aryl azides into cell surface glycans opens up new avenues for studying sialic acid-binding proteins and elucidating the role of sialic acid in essential processes such as signaling and cell adhesion.

  3. [Factors affecting plaque formation by Lassa virus in Vero cells].

    PubMed

    Lukashevich, I S; Vasiuchkov, A D; Mar'iankova, R F; Votiakov, V I

    1982-01-01

    The method of Porterfield and Allison was adapted for titration of the infectious activity of Lassa virus by the plaque formation in Vero cells. The virus was cloned, and the effect of the time of adsorption, pH, temperature, as well as polycations (DEAD-dextran, protamine sulphate) dimethylsuphoxide (DMSO), and trypsin added during adsorption or into the agar overlay on the effectiveness of plaque production by Lassa virus (virus titres, plaque size) were studied. The optimal adsorption time was found to be 1 1/2-2 hours, pH 8.0. The number of plaques produced by the virus was approximately similar at 35 degrees C. The substances under study did not enhance the efficacy of plaque formation, on the contrary, DMSO and high concentrations of polycations decreased plaque size.

  4. Aluminum fluoride affects the structure and functions of cell membranes.

    PubMed

    Suwalsky, M; Norris, B; Villena, F; Cuevas, F; Sotomayor, P; Zatta, P

    2004-06-01

    No useful biological function for aluminum has been found. To the contrary, it might play an important role in several pathologies, which could be related to its interactions with cell membranes. On the other hand, fluoride is a normal component of body fluids, soft tissues, bones and teeth. Its sodium salt is frequently added to drinking water to prevent dental caries. However, large doses cause severe pathological alterations. In view of the toxicity of Al(3+) and F(-) ions, it was thought of interest to explore the damaging effects that AlF(3) might induce in cell membranes. With this aim, it was incubated with human erythrocytes, which were examined by phase contrast and scanning electron microscopy, and molecular models of biomembranes. The latter consisted of large unilamellar vesicles (LUV) of dimyristoylphosphatidylcholine (DMPC) and bilayers of DMPC and dimyristoylphosphatidylethanolamine (DMPE) which were studied by fluorescence spectroscopy and X-ray diffraction, respectively. In order to understand the effects of AlF(3) on ion transport (principally sodium and chloride) we used the isolated toad skin to which electrophysiological measurements were applied. It was found that AlF(3) altered the shape of erythrocytes inducing the formation of echinocytes. This effect was explained by X-ray diffraction which revealed that AlF(3) perturbed the structure of DMPC, class of lipids located in the outer monolayer of the erythrocyte membrane. This result was confirmed by fluorescence spectroscopy on DMPC LUV. The biphasic (stimulatory followed by inhibitory) effects on the isolated skin suggested changes in apical Cl(-) secretion and moderate ATPase inactivation. PMID:15110101

  5. Parameters Affecting Spore Recovery from Wipes Used in Biological Surface Sampling ▿ †

    PubMed Central

    Da Silva, Sandra M.; Filliben, James J.; Morrow, Jayne B.

    2011-01-01

    The need for the precise and reliable collection of potential biothreat contaminants has motivated research in developing a better understanding of the variability in biological surface sampling methods. In this context, the objective of this work was to determine parameters affecting the efficiency of extracting Bacillus anthracis Sterne spores from commonly used wipe sampling materials and to describe performance using the interfacial energy concept. In addition, surface thermodynamics was applied to understand and predict surface sampling performance. Wipe materials were directly inoculated with known concentrations of B. anthracis spores and placed into extraction solutions, followed by sonication or vortexing. Experimental factors investigated included wipe material (polyester, cotton, and polyester-rayon), extraction solution (sterile deionized water [H2O], deionized water with 0.04% Tween 80 [H2O-T], phosphate-buffered saline [PBS], and PBS with 0.04% Tween 80 [PBST]), and physical dissociation method (vortexing or sonication). The most efficient extraction from wipes was observed for solutions containing the nonionic surfactant Tween 80. The increase in extraction efficiency due to surfactant addition was attributed to an attractive interfacial energy between Tween 80 and the centrifuge tube wall, which prevented spore adhesion. Extraction solution significantly impacted the extraction efficiency, as determined by statistical analysis (P < 0.05). Moreover, the extraction solution was the most important factor in extraction performance, followed by the wipe material. Polyester-rayon was the most efficient wipe material for releasing spores into solution by rank; however, no statistically significant difference between polyester-rayon and cotton was observed (P > 0.05). Vortexing provided higher spore recovery in H2O and H2O-T than sonication, when all three wipe materials and the reference control were considered (P < 0.05). PMID:21296945

  6. Osteoblastic cell behaviour on different titanium implant surfaces.

    PubMed

    Le Guehennec, Laurent; Lopez-Heredia, Marco-Antonio; Enkel, Benedicte; Weiss, Pierre; Amouriq, Yves; Layrolle, Pierre

    2008-05-01

    The osseointegration of oral implants is related to the early interactions between osteoblastic cells and titanium surfaces. The behaviour of osteoblastic MC3T3-E1 cells was compared on four different titanium surfaces: mirror-polished (Smooth-Ti), alumina grit-blasted (Alumina-Ti) or biphasic calcium phosphate ceramic grit-blasted (BCP-Ti) and a commercially available implant surface (SLA). Scanning electron microscopy and profilometry showed distinct microtopographies. The BCP-Ti group had higher average surface roughness (Ra=2.5 microm) than the other grit-blasted groups. Hydrophilicity and surfaces energies were determined on the different substrates by dynamic contact angle measurements. The most hydrophilic surface was the Alumina-Ti discs, while SLA was the most hydrophobic. The titanium surfaces were all oxidized as TiO2 and polluted by carbon contaminants, as determined by X-ray photoelectron spectroscopy. Alumina-Ti samples also exhibited aluminium peaks as a result of the blasting. The BCP-Ti discs contained traces of calcium and phosphorus. MC3T3-E1 cells attached, spread and proliferated on the substrates. For both the SLA and BCP-Ti groups, the entire surface was covered with a layer of osteoblastic cells after 2 days. At high magnification, the cells exhibited cytoplasmic extensions and filopodia. Compared with plastic, cell viability was similar with the Smooth-Ti, slightly lower with the Alumina-Ti and superior with the SLA and BCP-Ti groups. Alkaline phosphatase activity increased with the culture time whatever the substrate. This study shows that BCP-blasting produces rough titanium implants without surface contaminants. PMID:18226985

  7. Amplified effect of surface charge on cell adhesion by nanostructures

    NASA Astrophysics Data System (ADS)

    Xu, Li-Ping; Meng, Jingxin; Zhang, Shuaitao; Ma, Xinlei; Wang, Shutao

    2016-06-01

    Nano-biointerfaces with varied surface charge can be readily fabricated by integrating a template-based process with maleimide-thiol coupling chemistry. Significantly, nanostructures are employed for amplifying the effect of surface charge on cell adhesion, as revealed by the cell-adhesion performance, cell morphology and corresponding cytoskeletal organization. This study may provide a promising strategy for developing new biomedical materials with tailored cell adhesion for tissue implantation and regeneration.Nano-biointerfaces with varied surface charge can be readily fabricated by integrating a template-based process with maleimide-thiol coupling chemistry. Significantly, nanostructures are employed for amplifying the effect of surface charge on cell adhesion, as revealed by the cell-adhesion performance, cell morphology and corresponding cytoskeletal organization. This study may provide a promising strategy for developing new biomedical materials with tailored cell adhesion for tissue implantation and regeneration. Electronic supplementary information (ESI) available: Experimental details, SEM, KFM AFM, chemical modification and characterization. See DOI: 10.1039/c6nr00649c

  8. How the knowledge of genetic "makeup" and cellular data can affect the analysis of repolarization in surface electrocardiogram.

    PubMed

    Shimizu, Wataru

    2010-01-01

    This review article sought to describe patterns of repolarization on the surface electrocardiogram in inherited cardiac arrhythmias and to discuss how the knowledge of genetic makeup and cellular data can affect the analysis based on the data derived from the experimental studies using arterially perfused canine ventricular wedge preparations. Molecular genetic studies have established a link between a number of inherited cardiac arrhythmia syndromes and mutations in genes encoding cardiac ion channels or membrane components during the past 2 decades. Twelve forms of congenital long QT syndrome have been so far identified, and genotype-phenotype correlations have been investigated especially in the 3 major genotypes-LQT1, LQT2, and LQT3. Abnormal T waves are reported in the LQT1, LQT2, and LQT3, and the differences in the time course of repolarization of the epicardial, midmyocardial, and endocardial cells give rise to voltage gradients responsible for the manifestation of phenotypic appearance of abnormal T waves. Brugada syndrome is characterized by ST-segment elevation in leads V1 to V3 and an episode of ventricular fibrillation, in which 7 genotypes have been reported. An intrinsically prominent transient outward current (I(to))-mediated action potential notch and a subsequent loss of action potential dome in the epicardium, but not in the endocardium of the right ventricular outflow tract, give rise to a transmural voltage gradient, resulting in ST-segment elevation, and a subsequent phase 2 reentry-induced ventricular fibrillation. In conclusion, transmural electrical heterogeneity of repolarization across the ventricular wall profoundly affects the phenotypic manifestation of repolarization patterns on the surface electrocardiogram in inherited cardiac arrhythmias.

  9. Influence of anode surface chemistry on microbial fuel cell operation.

    PubMed

    Santoro, Carlo; Babanova, Sofia; Artyushkova, Kateryna; Cornejo, Jose A; Ista, Linnea; Bretschger, Orianna; Marsili, Enrico; Atanassov, Plamen; Schuler, Andrew J

    2015-12-01

    Self-assembled monolayers (SAMs) modified gold anodes are used in single chamber microbial fuel cells for organic removal and electricity generation. Hydrophilic (N(CH3)3(+), OH, COOH) and hydrophobic (CH3) SAMs are examined for their effect on bacterial attachment, current and power output. The different substratum chemistry affects the community composition of the electrochemically active biofilm formed and thus the current and power output. Of the four SAM-modified anodes tested, N(CH3)3(+) results in the shortest start up time (15 days), highest current achieved (225 μA cm(-2)) and highest MFC power density (40 μW cm(-2)), followed by COOH (150 μA cm(-2) and 37 μW cm(-2)) and OH (83 μA cm(-2) and 27 μW cm(-2)) SAMs. Hydrophobic SAM decreases electrochemically active bacteria attachment and anode performance in comparison to hydrophilic SAMs (CH3 modified anodes 7 μA cm(-2) anodic current and 1.2 μW cm(-2) MFC's power density). A consortium of Clostridia and δ-Proteobacteria is found on all the anode surfaces, suggesting a synergistic cooperation under anodic conditions.

  10. Surface strategies for control of neuronal cell adhesion: A review

    NASA Astrophysics Data System (ADS)

    Roach, P.; Parker, T.; Gadegaard, N.; Alexander, M. R.

    2010-06-01

    Material engineering methods have been used for many years to develop biomedical devices for use within the body to augment, repair or replace damaged tissues ranging from contact lenses to heart valves. Here we review the findings gathered from the wide and varied surface analytical approaches applied to study the interaction between biology and man-made materials. The key material characteristics identified to be important for biological recognition are surface chemistry, topography and compliance. Model surfaces with controlled chemistry and topography have provided insight into biological response to various types of topographical features over a wide range of length scales from nano to micrometres, along with 3D matrices that have been used as scaffolds to support cells for tissue formation. The cellular response to surfaces with localised areas of patterned chemistry and to those presenting gradually changing chemistry are discussed. Where previous reviews have been structured around specific classes of surface modification, e.g. self-assembly, or have broadly examined the response of various cells to numerous surfaces, we aim in this article to focus in particular on the tissues involved in the nervous system whilst providing a broad overview of key issues from the field of cell and protein surface interactions with surfaces. The goal of repair and treatment of diseases related to the central and peripheral nervous systems rely on understanding the local interfacial environment and controlling responses at the cellular level. The role of the protein layer deposited from serum containing media onto man-made surfaces is discussed. We highlight the particular problems associated with the repair of the nervous system, and review how neuronal attachment and axon guidance can be accomplished using various surface cues when cultured with single and multiple cell types. We include a brief glossary of techniques discussed in the body of this article aimed at the

  11. How Venus surface conditions evolution can be affected by large impacts at long timescales?

    NASA Astrophysics Data System (ADS)

    Gillmann, Cedric; Golabek, Gregor; Tackley, Paul

    2016-04-01

    Using numerical simulations, we investigate how the evolution of Venus' atmosphere and mantle is modified by large impacts, during Late Veneer and Late Heavy Bombardment. We propose a coupled model of mantle/atmosphere feedback. We also focus on volatile fluxes in and out of the atmosphere: atmospheric escape and degassing. The solid part of the planet is simulated using the StagYY code (Armann and Tackley, 2012) and releases volatiles into the atmosphere through degassing. Physical properties are depth-dependent. The assumed rheology is Newtonian diffusion creep plus plastic yielding. Atmospheric escape modeling involves two different aspects: hydrodynamic escape (0-500 Myr) and non-thermal escape mechanisms (dominant post 4 Ga). Hydrodynamic escape is the massive outflow of volatiles occurring when the solar energy input is strong. Post 4 Ga escape from non-thermal processes is comparatively low. The evolution of surface temperature is calculated from the greenhouse effect dependent on CO2 and water concentrations in the atmosphere, using a one-dimensional gray radiative-convective atmosphere model. It allows us to complete the coupling of the model: feedback of the atmosphere on the mantle is obtained by using surface temperature as a boundary condition for the convection. Large impacts are capable of contributing to (i) atmospheric escape, (ii) volatile replenishment and (iii) energy transfer to the mantle of the solid planet. We test a wide range of impactor parameters (size, velocity, timing) and different assumptions related to impact erosion (Shuvalov, 2010). For energy transfer, 2D distribution of the thermal anomaly created by the impact is used, leading to melting and subjected to transport by the mantle convection. Small (0-50 km) meteorites have a negligible effect on the global scale: they only affect the impact point and do not have lasting consequences on surface conditions. Medium ones (50-150 km) have strong short term influence through volatile

  12. Cell Surfaces in Plant-Microorganism Interactions

    PubMed Central

    Esquerré-Tugayé, Marie-Thérèse; Lamport, Derek T. A.

    1979-01-01

    Infection of muskmelon Cucumis melo seedlings by the fungus Colletotrichum lagenarium causes a 10-fold increase in the amount of cell wall hydroxyproline-rich glycoprotein. Evidence for this increase was provided by studying two specific markers of this glycoprotein, namely hydroxyproline and glycosylated serine. The lability of the O-glycosidic linkage of wall-bound glycosylated serine in the presence of hydrazine, was used to determine the amount of serine which is glycosylated. A large increase in the hydroxyproline content of infected plants is shown, but the ratios of glycosylated serine to hydroxyproline are similar in healthy and infected plants. As far as these markers are concerned, the hydroxyproline-rich glycoproteins secreted into the wall as a result of the disease are similar to those of healthy plants. In addition, the extent of glycosylation of the wall serine, in both healthy and infected plants, decreases as the plant ages. Serine- and hydroxyproline-rich (glyco)peptides were also isolated after trypsinolysis of the wall. These (glyco)peptides include the galactosyl-containing pentapeptide, serine-hydroxyproline4. This pentapeptide is characteristic of cell wall protein. PMID:16660956

  13. Antifouling property of highly oleophobic substrates for solar cell surfaces

    NASA Astrophysics Data System (ADS)

    Fukada, Kenta; Nishizawa, Shingo; Shiratori, Seimei

    2014-03-01

    Reduction of solar cell conversion efficiency by bird spoor or oil smoke is a common issue. Maintaining the surface of solar cells clean to retain the incident light is of utmost importance. In this respect, there has been growing interest in the area of superhydrophobicity for developing water repelling and self-cleaning surfaces. This effect is inspired by lotus leaves that have micro papillae covered with hydrophobic wax nanostructures. Superhydrophobic surfaces on transparent substrates have been developed for removing contaminants from solar cell surfaces. However, oil cannot be removed by superhydrophobic effect. In contrast, to prevent bird spoor, a highly oleophobic surface is required. In a previous study, we reported transparent-type fabrics comprising nanoparticles with a nano/micro hierarchical structure that ensured both oleophobicity and transparency. In the current study, we developed new highly oleophobic stripes that were constructed into semi-transparent oleophobic surfaces for solar cells. Solar cell performance was successfully maintained; the total transmittance was a key factor for determining conversion efficiency.

  14. Oxidation of cell surface thiol groups by contact sensitizers triggers the maturation of dendritic cells.

    PubMed

    Kagatani, Saori; Sasaki, Yoshinori; Hirota, Morihiko; Mizuashi, Masato; Suzuki, Mie; Ohtani, Tomoyuki; Itagaki, Hiroshi; Aiba, Setsuya

    2010-01-01

    p38 mitogen-activated protein kinase (MAPK) has a crucial role in the maturation of dendritic cells (DCs) by sensitizers. Recently, it has been reported that the oxidation of cell surface thiols by an exogenous impermeant thiol oxidizer can phosphorylate p38 MAPK. In this study, we examined whether sensitizers oxidize cell surface thiols of monocyte-derived DCs (MoDCs). When cell surface thiols were quantified by flow cytometry using Alexa fluor maleimide, all the sensitizers that we examined decreased cell surface thiols on MoDCs. To examine the effects of decreased cell surface thiols by sensitizers on DC maturation, we analyzed the effects of an impermeant thiol oxidizer, o-phenanthroline copper complex (CuPhen). The treatment of MoDCs with CuPhen decreased cell surface thiols, phosphorylated p38 MAPK, and induced MoDC maturation, that is, the augmentation of CD83, CD86, HLA-DR, and IL-8 mRNA, as well as the downregulation of aquaporin-3 mRNA. The augmentation of CD86 was significantly suppressed when MoDCs were pretreated with N-acetyl-L-cystein or treated with SB203580. Finally, we showed that epicutaneous application of 2,4-dinitrochlorobenzene on mouse skin significantly decreased cell surface thiols of Langerhans cells in vivo. These data suggest that the oxidation of cell surface thiols has some role in triggering DC maturation by sensitizers. PMID:19641517

  15. Electroporation chip for adherent cells on photochemically modified polymer surfaces

    NASA Astrophysics Data System (ADS)

    Olbrich, Michael; Rebollar, Esther; Heitz, Johannes; Frischauf, Irene; Romanin, Christoph

    2008-01-01

    We present a polytetrafluoroethylene electroporation microchip with integrated electrodes for transfection of adherent biological cells. For fabrication, UV-surface modification was employed in combination with metal deposition. UV irradiation in reactive atmosphere resulted in introduction of polar chemical groups into the polytetrafluoroethylene surface for significant adhesion enhancement of both biological cells as well as metal electrodes thereon. Electroporation was demonstrated by transfection of human embryonic kidney cells with the enhanced green fluorescent protein. Transparent, working at low voltages, and easy to handle, this chip yields the potential to reduce the amount of sequential working steps necessary for transfection.

  16. Influence of engineered surface on cell directionality and motility.

    PubMed

    Tang, Qing Yuan; Tong, Wing Yin; Shi, Jue; Shi, Peng; Lam, Yun Wah; Pang, Stella W

    2014-03-01

    Control of cell migration is important in numerous key biological processes, and is implicated in pathological conditions such as cancer metastasis and inflammatory diseases. Many previous studies indicated that cell migration could be guided by micropatterns fabricated on cell culture surfaces. In this study, we designed a polydimethylsiloxane cell culture substrate with gratings punctuated by corners and ends, and studied its effects on the behavior of MC3T3-E1 osteoblast cells. MC3T3-E1 cells elongated and aligned with the gratings, and the migration paths of the cells appeared to be guided by the grating pattern. Interestingly, more than 88% of the cells cultured on these patterns were observed to reverse their migration directions at least once during the 16 h examination period. Most of the reversal events occurred at the corners and the ends of the pattern, suggesting these localized topographical features induce an abrupt loss in directional persistence. Moreover, the cell speed was observed to increase temporarily right after each directional reversal. Focal adhesion complexes were more well-established in cells on the angular gratings than on flat surfaces, but the formation of filipodia appeared to be imbalanced at the corners and the ends, possibly leading to the loss of directional persistence. This study describes the first engineered cell culture surface that consistently induces changes in the directional persistence of adherent cells. This will provide an experimental model for the study of this phenomenon and a valuable platform to control the cell motility and directionality, which can be used for cell screening and selection. PMID:24589941

  17. Effects of plasma etching solar cell front surfaces

    SciTech Connect

    Taylor, W.E.; Bunyan, S.M.; Olson, C.E.

    1980-01-01

    A front surface plasma etch with Freon 14+8% O/sub 2/ or sulfur hexafluoride (SF/sub 6/) was found to improve terrestrial solar cell output. SEM studies of these samples revealed surface pitting on Freon 14 etched samples. About 50% of the improvement from Freon etched samples can be attributed to the light capturing effects of surface pits. Output increases from SF/sub 6/ plasma etched cells were found to be comparable with Freon etched cells after subtraction of the light trapping effects. The excess output improvement might be attributed to reduced junction depth or removal of near surface lattice damage. Investigations attempting to identify the cause are described. 1 ref.

  18. Modulating bone cells response onto starch-based biomaterials by surface plasma treatment and protein adsorption.

    PubMed

    Alves, Catarina M; Yang, Y; Carnes, D L; Ong, J L; Sylvia, V L; Dean, D D; Agrawal, C M; Reis, R L

    2007-01-01

    The effect of oxygen-based radio frequency glow discharge (rfGD) on the surface of different starch-based biomaterials (SBB) and the influence of proteins adsorption on modulating bone-cells behavior was studied. Bovine serum albumin, fibronectin and vitronectin were used in single and complex protein systems. RfGD-treated surfaces showed to increase in hydrophilicity and surface energy when compared to non-modified SBB. Biodegradable polymeric blends of cornstarch with cellulose acetate (SCA; 50/50wt%), ethylene vinyl alcohol (SEVA-C; 50/50wt%) and polycaprolactone (SPCL; 30/70wt%) were studied. SCA and SCA reinforced with 10% hydroxyapatite (HA) showed the highest degree of modification as result of the rfGD treatment. Protein and control solutions were used to incubate with the characterized SBB and, following this, MG63 osteoblast-like osteosarcoma cells were seeded over the surfaces. Cell adhesion and proliferation onto SCA was found to be enhanced for non-treated surfaces and on SCA+10%HA no alteration was brought up by the plasma modification. Onto SCA surfaces, BSA, FN and VN single solutions improved cell adhesion, and this same effect was found upscaled for ternary systems. In addition, plasma treated SEVA-C directed an increase in both adhesion and proliferation comparing to non-treated surfaces. Even though adhesion onto treated and untreated SPCL was quite similar, plasma modification clearly promoted MG63 cells proliferation. Regarding MG63 cells morphology it was shown that onto SEVA-C surfaces the variation of cell shape was primarily defined by the protein system, while onto SPCL it was mainly affected by the plasma treatment. PMID:17011619

  19. Modulating bone cells response onto starch-based biomaterials by surface plasma treatment and protein adsorption.

    PubMed

    Alves, Catarina M; Yang, Y; Carnes, D L; Ong, J L; Sylvia, V L; Dean, D D; Agrawal, C M; Reis, R L

    2007-01-01

    The effect of oxygen-based radio frequency glow discharge (rfGD) on the surface of different starch-based biomaterials (SBB) and the influence of proteins adsorption on modulating bone-cells behavior was studied. Bovine serum albumin, fibronectin and vitronectin were used in single and complex protein systems. RfGD-treated surfaces showed to increase in hydrophilicity and surface energy when compared to non-modified SBB. Biodegradable polymeric blends of cornstarch with cellulose acetate (SCA; 50/50wt%), ethylene vinyl alcohol (SEVA-C; 50/50wt%) and polycaprolactone (SPCL; 30/70wt%) were studied. SCA and SCA reinforced with 10% hydroxyapatite (HA) showed the highest degree of modification as result of the rfGD treatment. Protein and control solutions were used to incubate with the characterized SBB and, following this, MG63 osteoblast-like osteosarcoma cells were seeded over the surfaces. Cell adhesion and proliferation onto SCA was found to be enhanced for non-treated surfaces and on SCA+10%HA no alteration was brought up by the plasma modification. Onto SCA surfaces, BSA, FN and VN single solutions improved cell adhesion, and this same effect was found upscaled for ternary systems. In addition, plasma treated SEVA-C directed an increase in both adhesion and proliferation comparing to non-treated surfaces. Even though adhesion onto treated and untreated SPCL was quite similar, plasma modification clearly promoted MG63 cells proliferation. Regarding MG63 cells morphology it was shown that onto SEVA-C surfaces the variation of cell shape was primarily defined by the protein system, while onto SPCL it was mainly affected by the plasma treatment.

  20. Surface modified stainless steels for PEM fuel cell bipolar plates

    DOEpatents

    Brady, Michael P [Oak Ridge, TN; Wang, Heli [Littleton, CO; Turner, John A [Littleton, CO

    2007-07-24

    A nitridation treated stainless steel article (such as a bipolar plate for a proton exchange membrane fuel cell) having lower interfacial contact electrical resistance and better corrosion resistance than an untreated stainless steel article is disclosed. The treated stainless steel article has a surface layer including nitrogen-modified chromium-base oxide and precipitates of chromium nitride formed during nitridation wherein oxygen is present in the surface layer at a greater concentration than nitrogen. The surface layer may further include precipitates of titanium nitride and/or aluminum oxide. The surface layer in the treated article is chemically heterogeneous surface rather than a uniform or semi-uniform surface layer exclusively rich in chromium, titanium or aluminum. The precipitates of titanium nitride and/or aluminum oxide are formed by the nitriding treatment wherein titanium and/or aluminum in the stainless steel are segregated to the surface layer in forms that exhibit a low contact resistance and good corrosion resistance.

  1. Micropatterned surfaces for controlling cell adhesion and rolling under flow.

    PubMed

    Nalayanda, Divya D; Kalukanimuttam, Mahendran; Schmidtke, David W

    2007-04-01

    Cell adhesion and rolling on the vascular wall is critical to both inflammation and thrombosis. In this study we demonstrate the feasibility of using microfluidic patterning for controlling cell adhesion and rolling under physiological flow conditions. By controlling the width of the lines (50-1000 microm) and the spacing between them (50-100 microm) we were able to fabricate surfaces with well-defined patterns of adhesion molecules. We demonstrate the versatility of this technique by patterning surfaces with 3 different adhesion molecules (P-selectin, E-selectin, and von Willebrand Factor) and controlling the adhesion and rolling of three different cell types (neutrophils, Chinese Hamster Ovary cells, and platelets). By varying the concentration of the incubating solution we could control the surface ligand density and hence the cell rolling velocity. Finally by patterning surfaces with both P-selectin and von Willebrand Factor we could control the rolling of both leukocytes and platelets simultaneously. The technique described in this paper provides and effective and inexpensive way to fabricate patterned surfaces for use in cell rolling assays under physiologic flow conditions. PMID:17160704

  2. Sorption processes affecting arsenic solubility in oxidized surface sediments from Tulare Lake Bed, California

    USGS Publications Warehouse

    Gao, S.; Goldberg, S.; Herbel, M.J.; Chalmers, A.T.; Fujii, R.; Tanji, K.K.

    2006-01-01

    Elevated concentrations of arsenic (As) in shallow groundwater in Tulare Basin pose an environmental risk because of the carcinogenic properties of As and the potential for its migration to deep aquifers that could serve as a future drinking water source. Adsorption and desorption are hypothesized to be the major processes controlling As solubility in oxidized surface sediments where arsenate [As(V)] is dominant. This study examined the relationship between sorption processes and arsenic solubility in shallow sediments from the dry Tulare Lake bed by determining sorption isotherms, pH effect on solubility, and desorption-readsorption behavior (hysteresis), and by using a surface complexation model to describe sorption. The sediments showed a high capacity to adsorb As(V). Estimates of the maximum adsorption capacity were 92 mg As kg- 1 at pH 7.5 and 70 mg As kg- 1 at pH 8.5 obtained using the Langmuir adsorption isotherm. Soluble arsenic [> 97% As(V)] did not increase dramatically until above pH 10. In the native pH range (7.5-8.5), soluble As concentrations were close to the lowest, indicating that As was strongly retained on the sediment. A surface complexation model, the constant capacitance model, was able to provide a simultaneous fit to both adsorption isotherms (pH 7.5 and 8.5) and the adsorption envelope (pH effect on soluble As), although the data ranges are one order of magnitude different. A hysteresis phenomenon between As adsorbed on the sediment and As in solution phase was observed in the desorption-readsorption processes and differs from conventional hysteresis observed in adsorption-desorption processes. The cause is most likely due to modification of adsorbent surfaces in sediment samples upon extensive extractions (or desorption). The significance of the hysteresis phenomenon in affecting As solubility and mobility may be better understood by further microscopic studies of As interaction mechanisms with sediments subjected to extensive leaching

  3. Cell surface recycling in yeast: mechanisms and machineries.

    PubMed

    MacDonald, Chris; Piper, Robert C

    2016-04-15

    Sorting internalized proteins and lipids back to the cell surface controls the supply of molecules throughout the cell and regulates integral membrane protein activity at the surface. One central process in mammalian cells is the transit of cargo from endosomes back to the plasma membrane (PM) directly, along a route that bypasses retrograde movement to the Golgi. Despite recognition of this pathway for decades we are only beginning to understand the machinery controlling this overall process. The budding yeastSaccharomyces cerevisiae, a stalwart genetic system, has been routinely used to identify fundamental proteins and their modes of action in conserved trafficking pathways. However, the study of cell surface recycling from endosomes in yeast is hampered by difficulties that obscure visualization of the pathway. Here we briefly discuss how recycling is likely a more prevalent process in yeast than is widely appreciated and how tools might be built to better study the pathway.

  4. Cell surface GRP78 as a biomarker and target for suppressing glioma cells

    PubMed Central

    Kang, Bo Ram; Yang, Seung-Hoon; Chung, Bo-Ryehn; Kim, Woong; Kim, YoungSoo

    2016-01-01

    High-grade glioma is a highly malignant and metastatic brain cancer, resistant to many existing anticancer treatments. In such glioma cancer cells, the glucose-regulated protein 78 kDa (GRP78) is particularly highly up-regulated. Former studies have thus targeted mutation-free GRP78 not only to detect glioma cancer cells specifically but also to enhance cytotoxic effect. We focus on cell surface-expressed GRP78 as a target for suppressing high-grade glioma cell lines. Glioblastoma multiforme (GBM) cell line, highly malignant glioma cells, was first injected into 5-week-old athymic mice to confirm and compare GRP78 expression in vivo in xenografted and normal brain tissue. Immunofluorescence and immunoblotting were utilized to detect surface-localized GRP78 in diverse high-grade glioma cell lines. By treating glioma cell lines with the polyclonal N-20 antibody against surface-localized GRP78, we subsequently studied the significance of surface GRP78 to the survival and growth of the glioma cell lines. We found that inhibiting the function of surface GRP78 suppressed cancer cell survival and growth proving that the surface-expressed GRP78 is a vital receptor involved in the proliferation of high-grade glioma. Our findings provide opportunities to target surface GRP78 as a biomarker for high-grade glioma and to develop effective cell-specific anticancer therapy. PMID:27713511

  5. Surface modification of closed plastic bags for adherent cell cultivation

    NASA Astrophysics Data System (ADS)

    Lachmann, K.; Dohse, A.; Thomas, M.; Pohl, S.; Meyring, W.; Dittmar, K. E. J.; Lindenmeier, W.; Klages, C.-P.

    2011-07-01

    In modern medicine human mesenchymal stem cells are becoming increasingly important. However, a successful cultivation of this type of cells is only possible under very specific conditions. Of great importance, for instance, are the absence of contaminants such as foreign microbiological organisms, i.e., sterility, and the chemical functionalization of the ground on which the cells are grown. As cultivation of these cells makes high demands, a new procedure for cell cultivation has been developed in which closed plastic bags are used. For adherent cell growth chemical functional groups have to be introduced on the inner surface of the plastic bag. This can be achieved by a new, atmospheric-pressure plasma-based method presented in this paper. The method which was developed jointly by the Fraunhofer IST and the Helmholtz HZI can be implemented in automated equipment as is also shown in this contribution. Plasma process gases used include helium or helium-based gas mixtures (He + N2 + H2) and vapors of suitable film-forming agents or precursors such as APTMS, DACH, and TMOS in helium. The effect of plasma treatment is investigated by FTIR-ATR spectroscopy as well as surface tension determination based on contact angle measurements and XPS. Plasma treatment in nominally pure helium increases the surface tension of the polymer foil due to the presence of oxygen traces in the gas and oxygen diffusing through the gas-permeable foil, respectively, reacting with surface radical centers formed during contact with the discharge. Primary amino groups are obtained on the inner surface by treatment in mixtures with nitrogen and hydrogen albeit their amount is comparably small due to diffusion of oxygen through the gas-permeable bag, interfering with the plasma-amination process. Surface modifications introducing amino groups on the inner surface turned out to be most efficient in the promotion of cell growth.

  6. Oxidative Nanopatterning of Titanium Surface Influences mRNA and MicroRNA Expression in Human Alveolar Bone Osteoblastic Cells

    PubMed Central

    Wimmers Ferreira, Maidy Rehder; Rodrigo Fernandes, Roger; Freire Assis, Amanda; Dernowsek, Janaína A.; Passos, Geraldo A.; Variola, Fabio; Fittipaldi Bombonato-Prado, Karina

    2016-01-01

    Titanium implants have been extensively used in orthopedic and dental applications. It is well known that micro- and nanoscale surface features of biomaterials affect cellular events that control implant-host tissue interactions. To improve our understanding of how multiscale surface features affect cell behavior, we used microarrays to evaluate the transcriptional profile of osteoblastic cells from human alveolar bone cultured on engineered titanium surfaces, exhibiting the following topographies: nanotexture (N), nano+submicrotexture (NS), and rough microtexture (MR), obtained by modulating experimental parameters (temperature and solution composition) of a simple yet efficient chemical treatment with a H2SO4/H2O2 solution. Biochemical assays showed that cell culture proliferation augmented after 10 days, and cell viability increased gradually over 14 days. Among the treated surfaces, we observed an increase of alkaline phosphatase activity as a function of the surface texture, with higher activity shown by cells adhering onto nanotextured surfaces. Nevertheless, the rough microtexture group showed higher amounts of calcium than nanotextured group. Microarray data showed differential expression of 716 mRNAs and 32 microRNAs with functions associated with osteogenesis. Results suggest that oxidative nanopatterning of titanium surfaces induces changes in the metabolism of osteoblastic cells and contribute to the explanation of the mechanisms that control cell responses to micro- and nanoengineered surfaces. PMID:27200092

  7. Biological Functionalization of Carbon Nanotubes Using Cell Surface Mucin Mimics

    NASA Astrophysics Data System (ADS)

    Chen, Xing; Lee, Goo Soo; Zettl, Alex; Bertozzi, Carolyn

    2004-03-01

    Carbon Nanotubes (CNTs) are molecular wires with remarkable structural, electrical, and mechanical properties. Their potential applications in biology include sensing, imaging, and scaffolding for cell growth, but are presently limited by chemical incompatibility of the CNT surface with biological components and their aqueous milieu. Here we describe a biomimetic surface modification of CNTs using glycosylated polymers designed to mimic natural cell surface mucins. The polymers were end-functionalized with lipid tails for self-assembly on the CNT surface through hydrophobic interactions. Mucin mimic-coated CNTs were soluble in water, resisted non-specific protein binding and bound specifically to biomolecules via receptor-ligand interactions. This strategy for biomimetic surface engineering provides a means to bridge nanomaterials and biological systems.

  8. GLUCOCORTICOID-INDUCED ALTERATION OF THE SURFACE MEMBRANE OF CULTURED HEPATOMA CELLS

    PubMed Central

    Ballard, Philip L.; Tomkins, Gordon M.

    1970-01-01

    Glucocorticoids induce an alteration of the surface of hepatoma tissue culture (HTC) cells as expressed by changes in cell electrophoretic, antigenic, and adhesive properties. The alteration is assayed by the increased adhesiveness of induced cells for a glass surface. The induction process has a lag period of about 3 hr and attains a plateau level after 24–30 hr when 50–80% of the steroid-treated cells are firmly adhered. Less than 10% of untreated cells adhere under the same conditions. Induction is inhibited by actinomycin D and cycloheximide, demonstrates both pH and temperature dependence, and responds to changes in steroid concentration and structure. By contrast, the attachment per se of preinduced cells is not affected by inhibitors of RNA and protein synthesis, fluctuations of temperature and pH, and the presence or absence of the hormone. When the induction process is reversed by removal of steroid or addition of actinomycin D, preinduced adhesiveness is lost with a half-life of 13–24 hr, but in the presence of cycloheximide the loss is accelerated (t1/2 3–5.5 hr). These results suggest that glucocorticoids induce the biosynthesis of a protein which either modifies the cell surface (an enzyme) or is incorporated into surface structures (structural protein). PMID:4327515

  9. Expression of heat shock protein 90 at the cell surface in human neuroblastoma cells

    PubMed Central

    Cid, Cristina; Regidor, Ignacio; Poveda, Pedro D.

    2008-01-01

    In addition to the activity of heat shock protein 90 (Hsp90/HSPC) as a chaperone, some recent studies have reported expression of Hsp90 at the cell surface in certain types of cancer and nervous system cells. We study the expression of Hsp90 at the cell surface in human neuroblastoma (NB69) cells. Immunofluorescence experiments labeling with anti-Hsp90 antibodies on both nonpermeabilized cells and live cells detected Hsp90 at the cell surface. Hsp90 was also identified in a membrane fraction from subcellular fractionation. Cell-surface Hsp90 was significantly more expressed in undifferentiated proliferative spherical neuroblastoma cells than in differentiated flattened cells. In addition, spherical cells were significantly more sensitive to Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin compared to flattened cells. This paper describes the first evidence of cell-surface Hsp90 expression in a cancer cell line from nervous tissue and may indicate a novel target for anti-tumoral agents. PMID:18800240

  10. Biosensing based on surface plasmon resonance and living cells.

    PubMed

    Chabot, Vincent; Cuerrier, Charles M; Escher, Emanuel; Aimez, Vincent; Grandbois, Michel; Charette, Paul G

    2009-02-15

    We propose the combination of surface plasmon resonance (SPR) with living cells as a biosensing method. Our detection scheme is based on the premise that cellular activity induced by external agents is often associated with changes in cellular morphology, which in turn should lead to a variation of the effective refractive index at the interface between the cell membrane and the metal layer. We monitored surface plasmon resonance signals originating from a gold surface coated with cells on a custom apparatus after injection of various agents known to influence cellular activity and morphology. Specifically, we evaluated three types of stimulation: response to an endotoxin (lipopolysaccharides), a chemical toxin (sodium azide) and a physiological agonist (thrombin). A comparison with phase contrast microscopy reveals that SPR signal variations are associated with the induction of cell death for lipopolysaccharides treatment and a contraction of the cell body for sodium azide. Thrombin-induced cellular response shows a rapid decrease of the measured laser reflectance over 5min followed by a return to the original value. For this treatment, phase contrast micrographs relate the first phase of the SPR variation to cell contraction and increase of the intercellular gaps, whereas the recovery phase can be associated with a spreading of the cell on the sensing surface. Hence, the SPR signal is very consistent with the cellular response normally observed for these treatments. This confirms the validity of the biosensing method, which could be applied to a large variety of cellular responses involving shape remodeling induced by external agents. PMID:18845432

  11. How cells tiptoe on adhesive surfaces before sticking.

    PubMed

    Pierres, Anne; Benoliel, Anne-Marie; Touchard, Dominique; Bongrand, Pierre

    2008-05-15

    Cell membranes are studded with protrusions that were thoroughly analyzed with electron microscopy. However, the nanometer-scale three-dimensional motions generated by cell membranes to fit the topography of foreign surfaces and initiate adhesion remain poorly understood. Here, we describe the dynamics of surface deformations displayed by monocytic cells bumping against fibronectin-coated surfaces. We observed membrane undulations with typically 5 nm amplitude and 5-10 s lifetime. Cell membranes behaved as independent units of micrometer size. Cells detected the presence of foreign surfaces at 50 nm separation, resulting in time-dependent amplification of membrane undulations. Molecular contact then ensued with apparent cell-membrane separation of 30-40 nm, and this distance steadily decreased during the following tens of seconds. Contact maturation was associated with in-plane egress of bulky molecules and robust membrane fluctuations. Thus, membrane undulations may be the major determinant of cell sensitivity to substrate topography, outcome of interaction, and initial kinetics of contact extension. PMID:18234815

  12. Surface interactions affect the toxicity of engineered metal oxide nanoparticles toward Paramecium.

    PubMed

    Li, Kungang; Chen, Ying; Zhang, Wen; Pu, Zhichao; Jiang, Lin; Chen, Yongsheng

    2012-08-20

    To better understand the potential impacts of engineered metal oxide nanoparticles (NPs) in the ecosystem, we investigated the acute toxicity of seven different types of engineered metal oxide NPs against Paramecium multimicronucleatum, a ciliated protozoan, using the 48 h LC(50) (lethal concentration, 50%) test. Our results showed that the 48 h LC(50) values of these NPs to Paramecium ranged from 0.81 (Fe(2)O(3) NPs) to 9269 mg/L (Al(2)O(3) NPs); their toxicity to Paramecium increased as follows: Al(2)O(3) < TiO(2) < CeO(2) < ZnO < SiO(2) < CuO < Fe(2)O(3) NPs. On the basis of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, interfacial interactions between NPs and cell membrane were evaluated, and the magnitude of interaction energy barrier correlated well with the 48 h LC(50) data of NPs to Paramecium; this implies that metal oxide NPs with strong association with the cell surface might induce more severe cytotoxicity in unicellular organisms.

  13. Engineered microtopographies and surface chemistries direct cell attachment and function

    NASA Astrophysics Data System (ADS)

    Magin, Chelsea Marie

    Harrison, in 1914, first recognized that cells respond to physicochemical cues such as substratum topography when he observed that fibroblasts elongated while cultured on spider silk. Recently, techniques developed in the micro-electronics industry have been used to create molds for producing microscaled topographies with various shapes and spatial arrangements. Although these patterning techniques are well-established, very little is known about the mechanisms underlying cell sensing and response to microtopographies. In this work cellular micro-environments with varying surface topographies and chemistries were evaluated with marine organisms and mammalian cells to investigate cellular sensing and response. Biofouling---the accumulation of micro-organisms, plants, and animals on submerged surfaces---is an environmental and economic concern. Engineered topographies, replicated in polydimethylsiloxane elastomer (PDMSe) and functionalized poly(ethylene glycol)-dimethacrylate (PEGDMA) hydrogels, were evaluated for inhibition of marine fouling organism attachment. Microtopographies replicated in PDMSe inhibited attachment of the marine bacterium, Cobetia marina up to 99% versus smooth. The average normalized attachment densities of cells of C. marina and zoospores of the green algae Ulva on PDMSe topographies scaled inversely with the Engineered Roughness Index (ERIII), a representation of surface energy. Attachment densities of Ulva from four assays and C. marina from two growth phases to PDMSe surfaces scaled inversely with one equation: ERI II multiplied by the Reynolds number of the organism (Re) (R 2 = 0.77). The same microtopographies created in PDMSe reduced the initial attachment density and attachment strength of cells of the diatoms Navicula incerta and Seminavis robusta compared to smooth PDMSe. The average normalized attachment density of Navicula after exposure to shear stress (48 Pa) was correlated with the contact area between the diatom and a

  14. Cell surface syndecan-1 contributes to binding and function of macrophage migration inhibitory factor (MIF) on epithelial tumor cells.

    PubMed

    Pasqualon, Tobias; Lue, Hongqi; Groening, Sabine; Pruessmeyer, Jessica; Jahr, Holger; Denecke, Bernd; Bernhagen, Jürgen; Ludwig, Andreas

    2016-04-01

    Surface expressed proteoglycans mediate the binding of cytokines and chemokines to the cell surface and promote migration of various tumor cell types including epithelial tumor cells. We here demonstrate that binding of the chemokine-like inflammatory cytokine macrophage migration inhibitory factor (MIF) to epithelial lung and breast tumor cell lines A549 and MDA-MB231 is sensitive to enzymatic digestion of heparan sulphate chains and competitive inhibition with heparin. Moreover, MIF interaction with heparin was confirmed by chromatography and a structural comparison indicated a possible heparin binding site. These results suggested that proteoglycans carrying heparan sulphate chains are involved in MIF binding. Using shRNA-mediated gene silencing, we identified syndecan-1 as the predominant proteoglycan required for the interaction with MIF. MIF binding was decreased by induction of proteolytic shedding of syndecan-1, which could be prevented by inhibition of the metalloproteinases involved in this process. Finally, MIF induced the chemotactic migration of A549 cells, wound closure and invasion into matrigel without affecting cell proliferation. These MIF-induced responses were abrogated by heparin or by silencing of syndecan-1. Thus, our study indicates that syndecan-1 on epithelial tumor cells promotes MIF binding and MIF-mediated cell migration. This may represent a relevant mechanism through which MIF enhances tumor cell motility and metastasis.

  15. Factors affecting the development of somatic cell nuclear transfer embryos in Cattle.

    PubMed

    Akagi, Satoshi; Matsukawa, Kazutsugu; Takahashi, Seiya

    2014-01-01

    Nuclear transfer is a complex multistep procedure that includes oocyte maturation, cell cycle synchronization of donor cells, enucleation, cell fusion, oocyte activation and embryo culture. Therefore, many factors are believed to contribute to the success of embryo development following nuclear transfer. Numerous attempts to improve cloning efficiency have been conducted since the birth of the first sheep by somatic cell nuclear transfer. However, the efficiency of somatic cell cloning has remained low, and applications have been limited. In this review, we discuss some of the factors that affect the developmental ability of somatic cell nuclear transfer embryos in cattle.

  16. Biological Behavior of Osteoblast Cell and Apatite Forming Ability of the Surface Modified Ti Alloys.

    PubMed

    Zhao, Jingming; Hwang, K H; Choi, W S; Shin, S J; Lee, J K

    2016-02-01

    Titanium as one kind of biomaterials comes in direct contact with the body, making evaluation of biocompatibility an important aspect to biomaterials development. Surface chemistry of titanium plays an important role in osseointegration. Different surface modification alters the surface chemistry and result in different biological response. In this study, three kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coating successfully formed on the Ti surfaces in simulated body fluid. Strong mixed acid increased the roughness of the metal surface, because the porous and rough surface allows better adhesion between Ca-P coatings and substrates. After modification of titanium surface by mixed acidic solution and subsequently H2O2/HCL treatment evaluation of biocompatibility was conducted from hydroxyapatite formation by biomimetic process and cell viability on modified titanium surface. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Results from this study indicated that surface treatment methods affect the surface morphology, type of TiO2 layer formed and subsequent apatite deposition and biological responses. The thermo scientific alamarblue cell viability assay reagent is used to quantitatively measure the viability of mammalian cell lines, bacteria and fungi by incorporating a rapid, sensitive and reliable fluorometric/colorimetric growth indicator, without any toxic and side effect to cell line. In addition, mixed acid treatment uses a lower temperature and shorter time period than widely used alkali treatment.

  17. Biological Behavior of Osteoblast Cell and Apatite Forming Ability of the Surface Modified Ti Alloys.

    PubMed

    Zhao, Jingming; Hwang, K H; Choi, W S; Shin, S J; Lee, J K

    2016-02-01

    Titanium as one kind of biomaterials comes in direct contact with the body, making evaluation of biocompatibility an important aspect to biomaterials development. Surface chemistry of titanium plays an important role in osseointegration. Different surface modification alters the surface chemistry and result in different biological response. In this study, three kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coating successfully formed on the Ti surfaces in simulated body fluid. Strong mixed acid increased the roughness of the metal surface, because the porous and rough surface allows better adhesion between Ca-P coatings and substrates. After modification of titanium surface by mixed acidic solution and subsequently H2O2/HCL treatment evaluation of biocompatibility was conducted from hydroxyapatite formation by biomimetic process and cell viability on modified titanium surface. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Results from this study indicated that surface treatment methods affect the surface morphology, type of TiO2 layer formed and subsequent apatite deposition and biological responses. The thermo scientific alamarblue cell viability assay reagent is used to quantitatively measure the viability of mammalian cell lines, bacteria and fungi by incorporating a rapid, sensitive and reliable fluorometric/colorimetric growth indicator, without any toxic and side effect to cell line. In addition, mixed acid treatment uses a lower temperature and shorter time period than widely used alkali treatment. PMID:27433617

  18. Hydrodynamics of Sperm Cells near Surfaces

    PubMed Central

    Elgeti, Jens; Kaupp, U. Benjamin; Gompper, Gerhard

    2010-01-01

    Sperm are propelled by an actively beating tail, and display a wide variety of swimming patterns. When confined between two parallel walls, sperm swim either in circles or on curvilinear trajectories close to the walls. We employ mesoscale hydrodynamics simulations in combination with a mechanical sperm model to study the swimming behavior near walls. The simulations show that sperm become captured at the wall due to the hydrodynamic flow fields which are generated by the flagellar beat. The circular trajectories are determined by the chiral asymmetry of the sperm shape. For strong (weak) chirality, sperm swim in tight (wide) circles, with the beating plane of the flagellum oriented perpendicular (parallel) to the wall. For comparison, we also perform simulations based on a local anisotropic friction of the flagellum. In this resistive force approximation, surface adhesion and circular swimming patterns are obtained as well. However, the adhesion mechanism is now due to steric repulsion, and the orientation of the beating plane is different. Our model provides a theoretical framework that explains several distinct swimming behaviors of sperm near and far from a wall. Moreover, the model suggests a mechanism by which sperm navigate in a chemical gradient via a change of their shape. PMID:20712984

  19. Enhanced cell attachment using a novel cell culture surface presenting functional domains from extracellular matrix proteins

    PubMed Central

    Cooke, M. J.; Phillips, S. R.; Shah, D. S.H.; Athey, D.; Lakey, J. H.

    2008-01-01

    Many factors contribute to the creation and maintenance of a realistic environment for cell growth in vitro, e.g. the consistency of the growth medium, the addition of supplements, and the surface on which the cells grow. The nature of the surface on which cells are cultured plays an important role in their ability to attach, proliferate, migrate and function. Components of the extracellular matrix (ECM) are often used to coat glass or plastic surfaces to enhance cell attachment in vitro. Fragments of ECM molecules can be immobilised on surfaces in order to mimic the effects seen by whole molecules. In this study we evaluate the application of a novel technology for the immobilisation of functional domains of known ECM proteins in a controlled manner on a surface. By examining the adherence of cultured PC12 cells to alternative growth surfaces, we show that surfaces coated with motifs from collagen I, collagen IV, fibronectin and laminin can mimic surfaces coated with the corresponding whole molecules. Furthermore, we show that the adherence of cells can be controlled by modifying the hydropathic properties of the surface to either enhance or inhibit cell attachment. Collectively, these data demonstrate the application of a new technology to enable optimisation of cell growth in the tissue culture laboratory. PMID:19002844

  20. Surface loading affects internal pressure source characteristics derived from volcano deformation signals

    NASA Astrophysics Data System (ADS)

    Grapenthin, Ronni; Sigmundsson, Freysteinn; Ofeigsson, Benedikt; Sturkell, Erik

    2010-05-01

    InSAR observations prior to the Hekla 2000 eruption that show circular pattern of near field subsidence and far field inflation. We compare these data to the deformation pattern expected from pressure changes in a hypothetical, shallow magma reservoir. We estimate surface loading at the volcano to account for a displacement of 13.5mm-yr based on a comparison of expected Mogi source and observed InSAR line of sight velocity. From this we estimate an effective relaxation time of tr = 100yrs for this region. We infer an elastic plate thickness of H = 3.5km which controls the 15 - 20km radius of subsidence. We find that surface load signals in volcanic regions affect magmatic source model estimates significantly ; to the point of changing the preferred source model. This effect should be considered in virtually any volcanic region that shows lava flow emplacement, glacier dynamics, or sudden load removal (i.e., lateral blasts). Deformation data that remains uncorrected will most likely result in an overestimation of depth and volume of a magma reservoir. We find that the ratio of displacements aids the identification of composite signals and suggest that the ratio for GPS data be employed more rigorously in future studies since this allows volume independent source depth estimates.

  1. Molecular analysis of cell surface beta-1,4-galactosyltransferase function during cell migration.

    PubMed Central

    Appeddu, P A; Shur, B D

    1994-01-01

    Despite the identification and characterization of cell surface receptors for the extracellular matrix, it is unknown how their relative expression and cytoskeletal association regulate cell migration. Previous studies have identified beta-1,4-galactosyltransferase (GalTase; EC 2.4.1.38) on the surface of migrating cells, where it mediates cell migration on basal lamina matrices by associating with the cytoskeleton and binding to N-linked oligosaccharides in the E8 domain of laminin. In this study, the function of GalTase during cell migration was examined directly by analyzing the migration rate of stably transfected cell lines in which the relative level of surface GalTase and its ability to associate with the cytoskeleton were altered. We show here that the cytoskeleton contains a limiting, saturable, number of binding sites for surface GalTase. Furthermore, the rate of cell migration was inversely related to the ability of surface GalTase to associate with the cytoskeleton. Elevating surface GalTase in excess of the number of cytoskeleton-binding sites reduced the rate of cell migration, whereas decreasing the amount of surface GalTase available to bind the cytoskeleton increased migration rates. These results show that the rate of cell migration on basal lamina is directly dependent upon the expression of surface GalTase and the ability of this protein to associate with a limiting number of cytoskeleton-binding sites. Images PMID:8134355

  2. Cell surface differences of Naegleria fowleri and Naegleria lovaniensis exposed with surface markers.

    PubMed

    González-Robles, Arturo; Castañón, Guadalupe; Cristóbal-Ramos, Ana Ruth; Hernández-Ramírez, Verónica Ivonne; Omaña-Molina, Maritza; Martínez-Palomo, Adolfo

    2007-12-01

    Differences in the distribution of diverse cell surface coat markers were found between Naegleria fowleri and Naegleria lovaniensis. The presence of carbohydrate-containing components in the cell coat of the two species was detected by selective staining with ruthenium red and alcian blue. Using both markers, N. fowleri presented a thicker deposit than N. lovaniensis. The existence of exposed mannose or glucose residues was revealed by discriminatory agglutination with the plant lectin Concanavalin A. These sugar residues were also visualized at the cell surface of these parasites either by transmission electron microscopy or by fluorescein-tagged Concanavalin A. Using this lectin cap formation was induced only in N. fowleri. The anionic sites on the cell surface detected by means of cationized ferritin were more apparent in N. fowleri. Biotinylation assays confirmed that even though the two amoebae species have some analogous plasma membrane proteins, there is a clear difference in their composition.

  3. Calcium influences sensitivity to growth inhibition induced by a cell surface sialoglycopeptide

    NASA Technical Reports Server (NTRS)

    Betz, N. A.; Fattaey, H. K.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    While studies concerning mitogenic factors have been an important area of research for many years, much less is understood about the mechanisms of action of cell surface growth inhibitors. We have purified an 18 kDa cell surface sialoglycopeptide growth inhibitor (CeReS-18) which can reversibly inhibit the proliferation of diverse cell types. The studies discussed in this article show that three mouse keratinocyte cell lines exhibit sixty-fold greater sensitivity than other fibroblasts and epithelial-like cells to CeReS-18-induced growth inhibition. Growth inhibition induced by CeReS-18 treatment is a reversible process, and the three mouse keratinocyte cell lines exhibited either single or multiple cell cycle arrest points, although a predominantly G0/G1 cell cycle arrest point was exhibited in Swiss 3T3 fibroblasts. The sensitivity of the mouse keratinocyte cell lines to CeReS-18-induced growth inhibition was not affected by the degree of tumorigenic progression in the cell lines and was not due to differences in CeReS-18 binding affinity or number of cell surface receptors per cell. However, the sensitivity of both murine fibroblasts and keratinocytes could be altered by changing the extracellular calcium concentration, such that increased extracellular calcium concentrations resulted in decreased sensitivity to CeReS-18-induced proliferation inhibition. Thus the increased sensitivity of the murine keratinocyte cell lines to CeReS-18 could be ascribed to the low calcium concentration used in their propagation. Studies are currently under way investigating the role of calcium in CeReS-18-induced growth arrest. The CeReS-18 may serve as a very useful tool to study negative growth control and the signal transduction events associated with cell cycling.

  4. Cell and tissue behavior on micro-grooved surfaces.

    PubMed

    Walboomers, X F; Jansen, J A

    2001-11-01

    In this review, we discuss substrates and implant surfaces provided with micrometer-sized groove and ridge patterns. Such "microgrooves" influence cell behavior: the cells align themselves, and migrate guided by the surface grooves. This phenomenon is known as "contact guidance". First, cell structure and cell attachment behavior are described. Then techniques for the production of microgrooves are addressed, and a summary is given of a number of previous in-vitro and in-vivo experiments on this subject. Based on the knowledge of cell movement, we suggest a theory involving the dynamics of fibrous cellular components in the filopodium. Finally, future directions for this type of research, and implications for medical and dental implantology, are addressed.

  5. A Generalizable Platform for the Photoactivation of Cell Surface Receptors.

    PubMed

    Duc, Thinh Nguyen; Huse, Morgan

    2015-11-20

    Polarized signal transduction from cell surface receptors plays a central role in the development and homeostasis of multicellular organisms, and it also contributes to cellular dysfunction in many disease states. Understanding the molecular and cellular bases of polarized signaling requires experimental methods that provide precise spatiotemporal control of receptor activation. However, we currently lack strategies for inducing both sustained and spatially constrained signal transduction. In the present study, we combined synthetic and cell biological tools to develop a generalizable photoactivation approach for the stimulation of cell surface receptors. Our system, which is based upon the local decaging of a "universal" peptide ligand, is particularly well suited for the live imaging of single cells. We anticipate that it will greatly facilitate future mechanistic analyses of polarized signal transduction in a variety of cell types. PMID:26295186

  6. Cell patterning on polylactic acid through surface-tethered oligonucleotides.

    PubMed

    Matsui, Toshiki; Arima, Yusuke; Takemoto, Naohiro; Iwata, Hiroo

    2015-02-01

    Polylactic acid (PLA) is a candidate material to prepare scaffolds for 3-D tissue regeneration. However, cells do not adhere or proliferate well on the surface of PLA because it is hydrophobic. We report a simple and rapid method for inducing cell adhesion to PLA through DNA hybridization. Single-stranded DNA (ssDNA) conjugated to poly(ethylene glycol) (PEG) and to a terminal phospholipid (ssDNA-PEG-lipid) was used for cell surface modification. Through DNA hybridization, modified cells were able to attach to PLA surfaces modified with complementary sequence (ssDNA'). Different cell types can be attached to PLA fibers and films in a spatially controlled manner by using ssDNAs with different sequences. In addition, they proliferate well in a culture medium supplemented with fetal bovine serum. The coexisting modes of cell adhesion through DNA hybridization and natural cytoskeletal adhesion machinery revealed no serious effects on cell growth. The combination of a 3-D scaffold made of PLA and cell immobilization on the PLA scaffold through DNA hybridization will be useful for the preparation of 3-D tissue and organs.

  7. Endocytosis of cell surface material mediates cell plate formation during plant cytokinesis.

    PubMed

    Dhonukshe, Pankaj; Baluska, Frantisek; Schlicht, Markus; Hlavacka, Andrej; Samaj, Jozef; Friml, Jirí; Gadella, Theodorus W J

    2006-01-01

    Dividing plant cells perform a remarkable task of building a new cell wall within the cytoplasm in a few minutes. A long-standing paradigm claims that this primordial cell wall, known as the cell plate, is generated by delivery of newly synthesized material from Golgi apparatus-originated secretory vesicles. Here, we show that, in diverse plant species, cell surface material, including plasma membrane proteins, cell wall components, and exogenously applied endocytic tracers, is rapidly delivered to the forming cell plate. Importantly, this occurs even when de novo protein synthesis is blocked. In addition, cytokinesis-specific syntaxin KNOLLE as well as plasma membrane (PM) resident proteins localize to endosomes that fuse to initiate the cell plate. The rate of endocytosis is strongly enhanced during cell plate formation, and its genetic or pharmacological inhibition leads to cytokinesis defects. Our results reveal that endocytic delivery of cell surface material significantly contributes to cell plate formation during plant cytokinesis.

  8. Reversed cell imprinting, AFM imaging and adhesion analyses of cells on patterned surfaces.

    PubMed

    Zhou, Xiongtu; Shi, Jian; Zhang, Fan; Hu, Jie; Li, Xin; Wang, Li; Ma, Xueming; Chen, Yong

    2010-05-01

    Cell adhesion and motility depend strongly on the interactions between cells and cell culture substratum. To observe the cell morphology at the interface between cells and artificial substratum or patterned surfaces, we have developed a technique named reversed cell imprinting. After culture and chemical fixation of the cells on a patterned hole array, a liquid polymer was poured on and UV cured, allowing taking off the cell-polymer assembly for a direct observation of the underside cell surface using atomic force microscopy. As expected, we observed local deformation of the cell membrane in the hole area with a penetration depth strongly dependent on the size and depth of the hole as well as the culture time. Quantitative analyses of Hela cells on patterned surfaces of polydimethylsiloxane (PDMS) revealed that the penetration was also position dependent over the cell attachment area due to the non-homogeneous distribution of the membrane stress. With the increase of the culture time, the penetration depth was reduced, in a close correlation with the increase of the cell spreading area. Nevertheless, both cell seeding and adhesion efficiency on high density hole arrays could be significantly increased comparing to that on a smooth surface. Patterned substrates are increasingly required to produce and interrogate new biomaterials for therapeutic benefit. Overall, this work suggests a strategy to endow conventional imaging methods with added functionality to enable easy observation of the underside cell morphology on topographic patterns. PMID:20390138

  9. Saccharomyces cerevisiae mutant displaying beta-glucans on cell surface.

    PubMed

    Sakai, Yumiko; Azuma, Masayuki; Takada, Yuki; Umeyama, Takashi; Kaneko, Aki; Fujita, Tsuyoshi; Igarashi, Koichi; Ooshima, Hiroshi

    2007-02-01

    The deletion of MCD4 leads to an increase in beta-1,6-glucan level and a decrease in glycosylphosphatidylinositol-anchored protein and mannan levels in the cell wall of Saccharomyces cerevisiae, suggesting that mcd4 deletion mutant (mcd4Delta) displays beta-glucans on the cell surface without a mannan cover. An observation of the cell surface of mcd4Delta cells and an examination of the effect of contact between mcd4Delta cells and mouse macrophages indicated that macrophages were activated by contact with mcd4Delta cells displaying beta-glucans on the cell surface. We further examined the effect of intraperitoneal ethanol-fixed mcd4Delta cells on the survival period of mice infected with Candida albicans. mcd4Delta cells prolonged the survival period, implying that mcd4Delta cells may enhance the immune function of mice via macrophage activation. Moreover, we examined the structures of beta-glucans (i.e., alkali- and acetic acid-insoluble beta-glucans) extracted from mcd4Delta with (13)C-NMR and the effect of extracted beta-glucans on TNF-alpha secretion from macrophages. The structures of the beta-glucans from mcd4Delta differed from those of wild type (WT); however, there was no difference in tumor necrosis factor-alpha (TNF-alpha) secretion level between beta-glucans from mcd4Delta and those from WT. The yield of purified beta-glucans obtained from dry cells of mcd4Delta was higher than that obtained from dry cells of WT. mcd4Delta may be a superior strain for the preparation of beta-glucans. PMID:17368399

  10. Differentiation Between Intracellular and Cell Surface Glycosyl Transferases: Galactosyl Transferase Activity in Intact Cells and in Cell Homogenate

    PubMed Central

    Deppert, Wolfgang; Werchau, Hermann; Walter, Gernot

    1974-01-01

    Intact BHK (baby hamster kidney) cells catalyze the hydrolysis of UDP-galactose to free galactose. The generation of galactose from UDP-galactose and its intracellular utilization impede the detection of possible galactosyl transferases on the cell surface of intact cells. Several independent procedures have been used to distinguish between intracellular and cell surface glycosyl transferases. With these procedures, no evidence was obtained for the presence of detectable amounts of galactosyl transferase activity on the surface of BHK cells. The data suggest that galactosyl transferases do not play a general role in the phenomena of cell adhesion and contact inhibition. PMID:4528509

  11. Photodynamic induction of a bacterial cell surface polypeptide.

    PubMed Central

    Hoober, J K

    1977-01-01

    The photodynamic action of several dyes on cells of a bacterium, tentatively identified as a species of Arthrobacter, resulted in remarkable stimulation of synthesis of a polypeptide 21,000 daltons in mass. This polypeptide resides on the cell surface and can be solubilized by sodium dodecyl sulfate without lysis of the cells. Chlorophyllin and rose bengal are effective in inducing synthesis of the polypeptide in proportion to their ability to sensitize the photooxidation of histidine. Etiolated cells of the alga Chlamydomonas reinhardtii y-1 excrete a substance into the medium that also sensitized the photoinduction of the polypeptide. Images PMID:885841

  12. An Assessment of Cell Culture Plate Surface Chemistry for in Vitro Studies of Tissue Engineering Scaffolds.

    PubMed

    Röder, Alexander; García-Gareta, Elena; Theodoropoulos, Christina; Ristovski, Nikola; Blackwood, Keith A; Woodruff, Maria A

    2015-01-01

    The use of biopolymers as a three dimensional (3D) support structure for cell growth is a leading tissue engineering approach in regenerative medicine. Achieving consistent cell seeding and uniform cell distribution throughout 3D scaffold culture in vitro is an ongoing challenge. Traditionally, 3D scaffolds are cultured within tissue culture plates to enable reproducible cell seeding and ease of culture media change. In this study, we compared two different well-plates with different surface properties to assess whether seeding efficiencies and cell growth on 3D scaffolds were affected. Cell attachment and growth of murine calvarial osteoblast (MC3T3-E1) cells within a melt-electrospun poly-ε-caprolactone scaffold were assessed when cultured in either "low-adhesive" non-treated or corona discharged-treated well-plates. Increased cell adhesion was observed on the scaffold placed in the surface treated culture plates compared to the scaffold in the non-treated plates 24 h after seeding, although it was not significant. However, higher cell metabolic activity was observed on the bases of all well-plates than on the scaffold, except for day 21, well metabolic activity was higher in the scaffold contained in non-treated plate than the base. These results indicate that there is no advantage in using non-treated plates to improve initial cell seeding in 3D polymeric tissue engineering scaffolds, however non-treated plates may provide an improved metabolic environment for long-term studies. PMID:26703748

  13. Surface properties and early murine pre-osteoblastic cell responses of phosphoric acid modified titanium surface

    PubMed Central

    Osathanon, Thanaphum; Sawangmake, Chenphop; Ruangchainicom, Nanticha; Wutikornwipak, Pavitra; Kantukiti, Panisa; Nowwarote, Nunthawan; Pavasant, Prasit

    2015-01-01

    Aims The present study investigated the surface properties and murine pre-osteoblast cell (MC3T3-E1) responses of phosphoric acid (H3PO4) treated commercially pure titanium. Methods Titanium discs were treated with various concentration of H3PO4 (5%, 10%, and 20%; v/v) at 90 °C for 30 min. Surface properties were evaluated by profilometer, contact angle meter, and scanning electron microscopy (SEM) with energy dispersive X-rays. MC3T3-E1 attachment and spreading were evaluated by SEM and phalloidin immunohistochemistry staining. Results Surface roughness and wettability were not statistically difference among all experimental and control groups. Phosphate and oxygen were detected on H3PO4 treated surfaces. At 20 min, cell attachment was significantly higher in 10% and 20% H3PO4 treated groups compared to the control. Cells exhibited orientated-cytoskeleton fibers on 20% H3PO4 modified titanium surface. Though, there was no difference in cell spreading stage among all treatment groups. Conclusion H3PO4 treatment on titanium may influence early cell response, particularly on attachment and spreading. PMID:26937362

  14. Quantification of epidermal growth factor receptor expression level and binding kinetics on cell surfaces by surface plasmon resonance imaging.

    PubMed

    Zhang, Fenni; Wang, Shaopeng; Yin, Linliang; Yang, Yunze; Guan, Yan; Wang, Wei; Xu, Han; Tao, Nongjian

    2015-10-01

    Epidermal growth factor receptor (EGFR, also known as ErbB-1 or HER-1) is a membrane bound protein that has been associated with a variety of solid tumors and the control of cell survival, proliferation, and metabolism. Quantification of the EGFR expression level in cell membranes and the interaction kinetics with drugs are thus important for cancer diagnosis and treatment. Here we report mapping of the distribution and interaction kinetics of EGFR in their native environment with the surface plasmon resonance imaging (SPRi) technique. The monoclonal anti-EGFR antibody was used as a model drug in this study. The binding of the antibody to EGFR overexpressed A431 cells was monitored in real time, which was found to follow the first-order kinetics with an association rate constant (ka) and dissociation rate constant (kd) of (2.7 ± 0.6) × 10(5) M(-1) s(-1) and (1.4 ± 0.5) × 10(-4) s(-1), respectively. The dissociation constant (KD) was determined to be 0.53 ± 0.26 nM with up to seven-fold variation among different individual A431 cells. In addition, the averaged A431 cell surface EGFR density was found to be 636/μm(2) with an estimation of 5 × 10(5) EGFR per cell. Additional measurement also revealed that different EGFR positive cell lines (A431, HeLa, and A549) show receptor density dependent anti-EGFR binding kinetics. The results demonstrate that SPRi is a valuable tool for direct quantification of membrane protein expression level and ligand binding kinetics at single cell resolution. Our findings show that the local environment affects the drug-receptor interactions, and in situ measurement of membrane protein binding kinetics is important.

  15. Assessing state stem cell programs in the United States: how has state funding affected publication trends?

    PubMed

    Alberta, Hillary B; Cheng, Albert; Jackson, Emily L; Pjecha, Matthew; Levine, Aaron D

    2015-02-01

    Several states responded to federal funding limitations placed on human embryonic stem cell research and the potential of the field by creating state stem cell funding programs, yet little is known about the impact of these programs. Here we examine how state programs have affected publication trends in four states.

  16. Investigation of the Cell Surface Proteome of Human Periodontal Ligament Stem Cells

    PubMed Central

    Xiong, Jimin; Menicanin, Danijela; Marino, Victor

    2016-01-01

    The present study examined the cell surface proteome of human periodontal ligament stem cells (PDLSC) compared to human fibroblasts. Cell surface proteins were prelabelled with CyDye before processing to extract the membrane lysates, which were separated using 2D electrophoresis. Selected differentially expressed protein “spots” were identified using Mass spectrometry. Four proteins were selected for validation: CD73, CD90, Annexin A2, and sphingosine kinase 1 previously associated with mesenchymal stem cells. Flow cytometric analysis found that CD73 and CD90 were highly expressed by human PDLSC and gingival fibroblasts but not by keratinocytes, indicating that these antigens could be used as potential markers for distinguishing between mesenchymal cells and epithelial cell populations. Annexin A2 was also found to be expressed at low copy number on the cell surface of human PDLSC and gingival fibroblasts, while human keratinocytes lacked any cell surface expression of Annexin A2. In contrast, sphingosine kinase 1 expression was detected in all the cell types examined using immunocytochemical analysis. These proteomic studies form the foundation to further define the cell surface protein expression profile of PDLSC in order to better characterise this cell population and help develop novel strategies for the purification of this stem cell population. PMID:27579043

  17. Investigation of the Cell Surface Proteome of Human Periodontal Ligament Stem Cells.

    PubMed

    Xiong, Jimin; Menicanin, Danijela; Zilm, Peter S; Marino, Victor; Bartold, P Mark; Gronthos, Stan

    2016-01-01

    The present study examined the cell surface proteome of human periodontal ligament stem cells (PDLSC) compared to human fibroblasts. Cell surface proteins were prelabelled with CyDye before processing to extract the membrane lysates, which were separated using 2D electrophoresis. Selected differentially expressed protein "spots" were identified using Mass spectrometry. Four proteins were selected for validation: CD73, CD90, Annexin A2, and sphingosine kinase 1 previously associated with mesenchymal stem cells. Flow cytometric analysis found that CD73 and CD90 were highly expressed by human PDLSC and gingival fibroblasts but not by keratinocytes, indicating that these antigens could be used as potential markers for distinguishing between mesenchymal cells and epithelial cell populations. Annexin A2 was also found to be expressed at low copy number on the cell surface of human PDLSC and gingival fibroblasts, while human keratinocytes lacked any cell surface expression of Annexin A2. In contrast, sphingosine kinase 1 expression was detected in all the cell types examined using immunocytochemical analysis. These proteomic studies form the foundation to further define the cell surface protein expression profile of PDLSC in order to better characterise this cell population and help develop novel strategies for the purification of this stem cell population. PMID:27579043

  18. A Rapid Method for Refolding Cell Surface Receptors and Ligands

    PubMed Central

    Zhai, Lu; Wu, Ling; Li, Feng; Burnham, Robert S.; Pizarro, Juan C.; Xu, Bin

    2016-01-01

    Production of membrane-associated cell surface receptors and their ligands is often a cumbersome, expensive, and time-consuming process that limits detailed structural and functional characterization of this important class of proteins. Here we report a rapid method for refolding inclusion-body-based, recombinant cell surface receptors and ligands in one day, a speed equivalent to that of soluble protein production. This method efficiently couples modular on-column immobilized metal ion affinity purification and solid-phase protein refolding. We demonstrated the general utility of this method for producing multiple functionally active immunoreceptors, ligands, and viral decoys, including challenging cell surface proteins that cannot be produced using typical dialysis- or dilution-based refolding approaches. PMID:27215173

  19. Cell surface engineering of microorganisms towards adsorption of heavy metals.

    PubMed

    Li, Peng-Song; Tao, Hu-Chun

    2015-06-01

    Heavy metal contamination has become a worldwide environmental concern due to its toxicity, non-degradability and food-chain bioaccumulation. Conventional physical and chemical treatment methods for heavy metal removal have disadvantages such as cost-intensiveness, incomplete removal, secondary pollution and the lack of metal specificity. Microbial biomass-based biosorption is one of the approaches gaining increasing attention because it is effective, cheap, and environmental friendly and can work well at low concentrations. To enhance the adsorption properties of microbial cells to heavy metal ions, the cell surface display of various metal-binding proteins/peptides have been performed using a cell surface engineering approach. The surface engineering of Gram-negative bacteria, Gram-positive bacteria and yeast towards the adsorption of heavy metals are reviewed in this article. The problems and future perspectives of this technology are discussed.

  20. Surface complexation of aluminum on isolated fish gill cells

    SciTech Connect

    Wilkinson, K.J. Campbell, G.C.; Bertsch, P.M.; Jagoe, C.H.

    1993-06-01

    Cells from the gills of largemouth bass (Micropterus salmoides) were isolated and exposed to dilute solutions of Al, Al in the presence of fluoride, or Al plus dissolved organic matter (DOM) to determine the cells` metal binding potential in an acidic medium. Microelectrophoresis was employed to monitor the extent of aluminum sorption to cells in the presence of added ligand. In the absence of Al, the gill cells exhibit an appreciable negative charge; Al binding to the cell surface increases the electric potential at the shear plane and leads to a reduction in the cell`s (negative) electrophoretic mobility. In the presence of both Al and F, aluminum complexation at the gill surface is only marginally reduced; the formation of a mixed ligand complex, [F-Al-L-cell], is proposed to account for the observed results. The presence of such ternary complexes was subsequently verified by {sup 19}F nuclear magnetic resonance spectroscopy and by potentiometry. Addition of DOM increased the negative electrophoretic mobility of the isolated gill cells both in the presence and absence of aluminum (7.4 {mu}M). 45 refs., 7 figs., 1 tab.

  1. CELL SURFACE ANTIGENS OF A MOUSE TESTICULAR TERATOMA

    PubMed Central

    Gooding, Linda R.; Edidin, Michael

    1974-01-01

    Rabbit antisera to a mouse testicular teratoma, absorbed with normal mouse tissues, react by immunofluorescence with plasma membrane antigens of a variety of transplantable mouse tumor cells and transformed fibroblast cell lines including Clone 1D, SV-40-3T3, and 3T12. Trypsin treatment of cells of "normal" lines, 3T3 and FR-SV-3T3, uncovers reactivity on these as well. Early passage mouse embryo fibroblast cell cultures do not react even after trypsinization. By cross-absorbtion studies, the anti-teratoma serum appears to react with an antigen common to most tumor cells investigated thus far. When this antigen on Clone 1D cells is "capped," H-2 antigens collect with the teratoma antigens in the cap indicating a physical association between the molecules. Molecules specified by both the H-2D and H-2K regions are bound to the teratoma antigens in the Clone 1D plasma membrane. This antigen is also found in soluble tumor cell fractions where it is believed to be free of H-2. A second cell surface antigen defined by anti-teratoma serum is expressed only by hepatoma and teratoma itself. This second antigen is apparently a secretory product of teratoma cells. A third surface antigen defined by anti-teratoma serum appears to be specific for the teratoma. PMID:4365513

  2. Surface free energy activated high-throughput cell sorting.

    PubMed

    Zhang, Xinru; Zhang, Qian; Yan, Tao; Jiang, Zeyi; Zhang, Xinxin; Zuo, Yi Y

    2014-09-16

    Cell sorting is an important screening process in microbiology, biotechnology, and clinical research. Existing methods are mainly based on single-cell analysis as in flow cytometric and microfluidic cell sorters. Here we report a label-free bulk method for sorting cells by differentiating their characteristic surface free energies (SFEs). We demonstrated the feasibility of this method by sorting model binary cell mixtures of various bacterial species, including Pseudomonas putida KT2440, Enterococcus faecalis ATCC 29212, Salmonella Typhimurium ATCC 14028, and Escherichia coli DH5α. This method can effectively separate 10(10) bacterial cells within 30 min. Individual bacterial species can be sorted with up to 96% efficiency, and the cell viability ratio can be as high as 99%. In addition to its capacity of sorting evenly mixed bacterial cells, we demonstrated the feasibility of this method in selecting and enriching cells of minor populations in the mixture (presenting at only 1% in quantity) to a purity as high as 99%. This SFE-activated method may be used as a stand-alone method for quickly sorting a large quantity of bacterial cells or as a prescreening tool for microbial discrimination. Given its advantages of label-free, high-throughput, low cost, and simplicity, this SFE-activated cell sorting method has potential in various applications of sorting cells and abiotic particles. PMID:25184988

  3. Surface-Enhanced Raman Scattering Nanoparticles as Optical Labels for Imaging Cell Surface Proteins

    NASA Astrophysics Data System (ADS)

    MacLaughlin, Christina M.

    Assaying the expression of cell surface proteins has widespread application for characterizing cell type, developmental stage, and monitoring disease transformation. Immunophenotyping is conducted by treating cells with labelled targeting moieties that have high affinity for relevant surface protein(s). The sensitivity and specificity of immunophenotyping is defined by the choice of contrast agent and therefore, the number of resolvable signals that can be used to simultaneously label cells. Narrow band width surface-enhanced Raman scattering (SERS) nanoparticles are proposed as optical labels for multiplexed immunophenotying. Two types of surface coatings were investigated to passivate the gold nanoparticles, incorporate SERS functionality, and to facilitate attachment of targeting antibodies. Thiolated poly(ethylene glycol) forms dative bonds with the gold surface and is compatible with multiple physisorbed Raman-active reporter molecules. Ternary lipid bilayers are used to encapsulate the gold nanoparticles particles, and incorporate three different classes of Raman reporters. TEM, UV-Visible absorbance spectroscopy, DLS, and electrophoretic light scattering were used characterize the particle coating. Colourimetric protein assay, and secondary antibody labelling were used to quantify the antibody conjugation. Three different in vitromodels were used to investigate the binding efficacy and specificity of SERS labels for their biomarker targets. Primary human CLL cells, LY10 B lymphoma, and A549 adenocarcinoma lines were targeted. Dark field imaging was used to visualize the colocalization of SERS labels with cells, and evidence of receptor clustering was obtained based on colour shifts of the particles' Rayleigh scattering. Widefield, and spatially-resolved Raman spectra were used to detect labels singly, and in combination from labelled cells. Fluorescence flow cytometry was used to test the particles' binding specificity, and SERS from labelled cells was also

  4. Apoptotic epithelial cells control the abundance of Treg cells at barrier surfaces.

    PubMed

    Nakahashi-Oda, Chigusa; Udayanga, Kankanam Gamage Sanath; Nakamura, Yoshiyuki; Nakazawa, Yuta; Totsuka, Naoya; Miki, Haruka; Iino, Shuichi; Tahara-Hanaoka, Satoko; Honda, Shin-ichiro; Shibuya, Kazuko; Shibuya, Akira

    2016-04-01

    Epithelial tissues continually undergo apoptosis. Commensal organisms that inhabit the epithelium influence tissue homeostasis, in which regulatory T cells (Treg cells) have a central role. However, the physiological importance of epithelial cell apoptosis and how the number of Treg cells is regulated are both incompletely understood. Here we found that apoptotic epithelial cells negatively regulated the commensal-stimulated proliferation of Treg cells. Gut commensals stimulated CX3CR1(+)CD103(-)CD11b(+) dendritic cells (DCs) to produce interferon-β (IFN-β), which augmented the proliferation of Treg cells in the intestine. Conversely, phosphatidylserine exposed on apoptotic epithelial cells suppressed IFN-β production by the DCs via inhibitory signaling mediated by the cell-surface glycoprotein CD300a and thus suppressed Treg cell proliferation. Our findings reveal a regulatory role for apoptotic epithelial cells in maintaining the number of Treg cell and tissue homeostasis. PMID:26855029

  5. Cells Sensing Mechanical Cues: Stiffness Influences the Lifetime of Cell-Extracellular Matrix Interactions by Affecting the Loading Rate.

    PubMed

    Jiang, Li; Sun, Zhenglong; Chen, Xiaofei; Li, Jing; Xu, Yue; Zu, Yan; Hu, Jiliang; Han, Dong; Yang, Chun

    2016-01-26

    The question of how cells sense substrate mechanical cues has gained increasing attention among biologists. By introducing contour-based data analysis to single-cell force spectroscopy, we identified a loading-rate threshold for the integrin α2β1-DGEA bond beyond which a dramatic increase in bond lifetime was observed. On the basis of mechanical cues (elasticity or topography), the effective spring constant of substrates k is mapped to the loading rate r under actomyosin pulling speed v, which, in turn, affects the lifetime of the integrin-ligand bond. Additionally, downregulating v with a low-dose blebbistatin treatment promotes the neuronal lineage specification of mesenchymal stem cells on osteogenic stiff substrates. Thus, sensing of the loading rate is central to how cells sense mechanical cues that affect cell-extracellular matrix interactions and stem cell differentiation.

  6. Surface-directed assembly of cell-laden microgels.

    PubMed

    Du, Yanan; Ghodousi, Majid; Lo, Edward; Vidula, Mahesh K; Emiroglu, Onur; Khademhosseini, Ali

    2010-02-15

    Cell-laden microscale hydrogels (microgels) can be used as tissue building blocks and assembled to create 3D tissue constructs with well-defined microarchitecture. In this article, we present a bottom-up approach to achieve microgel assembly on a patterned surface. Driven by surface tension, the hydrophilic microgels can be assembled into well-defined shapes on a glass surface patterned with hydrophobic and hydrophilic regions. We found that the cuboidic microgels ( approximately 100-200 microm in width) could self-assemble into defined shapes with high fidelity to the surface patterns. The microgel assembly process was improved by increasing the hydrophilicity of the microgels and reducing the surface tension of the surrounding solution. The assembled microgels were stabilized by a secondary crosslinking step. Assembled microgels containing cells stained with different dyes were fabricated to demonstrate the application of this approach for engineering microscale tissue constructs containing multiple cell types. This bottom-up approach enables rapid fabrication of cell-laden microgel assemblies with pre-defined geometrical and biological features, which is easily scalable and can be potentially used in microscale tissue engineering applications.

  7. Cell surface proteome of the marine planctomycete Rhodopirellula baltica.

    PubMed

    Voigt, Birgit; Hieu, Cao Xuan; Hempel, Kristina; Becher, Dörte; Schlüter, Rabea; Teeling, Hanno; Glöckner, Frank Oliver; Amann, Rudolf; Hecker, Michael; Schweder, Thomas

    2012-06-01

    The surface proteome (surfaceome) of the marine planctomycete Rhodopirellula baltica SH1(T) was studied using a biotinylation and a proteinase K approach combined with SDS-PAGE and mass spectrometry. 52 of the proteins identified in both approaches could be assigned to the group of potential surface proteins. Among them are some high molecular weight proteins, potentially involved in cell-cell attachment, that contain domains shown before to be typical for surface proteins like cadherin/dockerin domains, a bacterial adhesion domain or the fasciclin domain. The identification of proteins with enzymatic functions in the R. baltica surfaceome provides further clues for the suggestion that some degradative enzymes may be anchored onto the cell surface. YTV proteins, which have been earlier supposed to be components of the proteinaceous cell wall of R. baltica, were detected in the surface proteome. Additionally, 8 proteins with a novel protein structure combining a conserved type IV pilin/N-methylation domain and a planctomycete-typical DUF1559 domain were identified. PMID:22623273

  8. Autonomous molecular cascades for evaluation of cell surfaces

    NASA Astrophysics Data System (ADS)

    Rudchenko, Maria; Taylor, Steven; Pallavi, Payal; Dechkovskaia, Alesia; Khan, Safana; Butler, Vincent P., Jr.; Rudchenko, Sergei; Stojanovic, Milan N.

    2013-08-01

    Molecular automata are mixtures of molecules that undergo precisely defined structural changes in response to sequential interactions with inputs. Previously studied nucleic acid-based automata include game-playing molecular devices (MAYA automata) and finite-state automata for the analysis of nucleic acids, with the latter inspiring circuits for the analysis of RNA species inside cells. Here, we describe automata based on strand-displacement cascades directed by antibodies that can analyse cells by using their surface markers as inputs. The final output of a molecular automaton that successfully completes its analysis is the presence of a unique molecular tag on the cell surface of a specific subpopulation of lymphocytes within human blood cells.

  9. 3D surface topology guides stem cell adhesion and differentiation.

    PubMed

    Viswanathan, Priyalakshmi; Ondeck, Matthew G; Chirasatitsin, Somyot; Ngamkham, Kamolchanok; Reilly, Gwendolen C; Engler, Adam J; Battaglia, Giuseppe

    2015-06-01

    Polymerized high internal phase emulsion (polyHIPE) foams are extremely versatile materials for investigating cell-substrate interactions in vitro. Foam morphologies can be controlled by polymerization conditions to result in either open or closed pore structures with different levels of connectivity, consequently enabling the comparison between 2D and 3D matrices using the same substrate with identical surface chemistry conditions. Additionally, here we achieve the control of pore surface topology (i.e. how different ligands are clustered together) using amphiphilic block copolymers as emulsion stabilizers. We demonstrate that adhesion of human mesenchymal progenitor (hES-MP) cells cultured on polyHIPE foams is dependent on foam surface topology and chemistry but is independent of porosity and interconnectivity. We also demonstrate that the interconnectivity, architecture and surface topology of the foams has an effect on the osteogenic differentiation potential of hES-MP cells. Together these data demonstrate that the adhesive heterogeneity of a 3D scaffold could regulate not only mesenchymal stem cell attachment but also cell behavior in the absence of soluble growth factors.

  10. 3D Surface Topology Guides Stem Cell Adhesion and Differentiation

    PubMed Central

    Viswanathan, Priyalakshmi; Ondeck, Matthew G.; Chirasatitsin, Somyot; Nghamkham, Kamolchanok; Reilly, Gwendolen C.; Engler, Adam J.; Battaglia, Giuseppe

    2015-01-01

    Polymerized high internal phase emulsion (polyHIPE) foams are extremely versatile materials for investigating cell-substrate interactions in vitro. Foam morphologies can be controlled by polymerization conditions to result in either open or closed pore structures with different levels of connectivity, consequently enabling the comparison between 2D and 3D matrices using the same substrate with identical surface chemistry conditions. Additionally, here we achieve the control of pore surface topology (i.e. how different ligands are clustered together) using amphiphilic block copolymers as emulsion stabilisers. We demonstrate that adhesion of human mesenchymal progenitor (hES-MP) cells cultured on polyHIPE foams is dependent on foam surface topology and chemistry but is independent of porosity and interconnectivity. We also demonstrate that the interconnectivity, architecture and surface topology of the foams has an effect on the osteogenic differentiation potential of hES-MP cells. Together these data demonstrate that the adhesive heterogeneity of a 3D scaffold could regulate not only mesenchymal stem cell attachment but also cell behavior in the absence of soluble growth factors. PMID:25818420

  11. An update on cell surface proteins containing extensin-motifs.

    PubMed

    Borassi, Cecilia; Sede, Ana R; Mecchia, Martin A; Salgado Salter, Juan D; Marzol, Eliana; Muschietti, Jorge P; Estevez, Jose M

    2016-01-01

    In recent years it has become clear that there are several molecular links that interconnect the plant cell surface continuum, which is highly important in many biological processes such as plant growth, development, and interaction with the environment. The plant cell surface continuum can be defined as the space that contains and interlinks the cell wall, plasma membrane and cytoskeleton compartments. In this review, we provide an updated view of cell surface proteins that include modular domains with an extensin (EXT)-motif followed by a cytoplasmic kinase-like domain, known as PERKs (for proline-rich extensin-like receptor kinases); with an EXT-motif and an actin binding domain, known as formins; and with extracellular hybrid-EXTs. We focus our attention on the EXT-motifs with the short sequence Ser-Pro(3-5), which is found in several different protein contexts within the same extracellular space, highlighting a putative conserved structural and functional role. A closer understanding of the dynamic regulation of plant cell surface continuum and its relationship with the downstream signalling cascade is a crucial forthcoming challenge.

  12. Dynamic and reversible surface topography influences cell morphology.

    PubMed

    Kiang, Jennifer D; Wen, Jessica H; del Álamo, Juan C; Engler, Adam J

    2013-08-01

    Microscale and nanoscale surface topography changes can influence cell functions, including morphology. Although in vitro responses to static topography are novel, cells in vivo constantly remodel topography. To better understand how cells respond to changes in topography over time, we developed a soft polyacrylamide hydrogel with magnetic nickel microwires randomly oriented in the surface of the material. Varying the magnetic field around the microwires reversibly induced their alignment with the direction of the field, causing the smooth hydrogel surface to develop small wrinkles; changes in surface roughness, ΔRRMS , ranged from 0.05 to 0.70 μm and could be oscillated without hydrogel creep. Vascular smooth muscle cell morphology was assessed when exposed to acute and dynamic topography changes. Area and shape changes occurred when an acute topographical change was imposed for substrates exceeding roughness of 0.2 μm, but longer-term oscillating topography did not produce significant changes in morphology irrespective of wire stiffness. These data imply that cells may be able to use topography changes to transmit signals as they respond immediately to changes in roughness.

  13. The Role of Surface Receptor Density in Surface-Initiated Polymerizations for Cancer Cell Isolation.

    PubMed

    Lilly, Jacob L; Berron, Brad J

    2016-06-01

    Fluid biopsies potentially offer a minimally invasive alternative to traditional tissue biopsies for the continual monitoring of metastatic cancer. Current established technologies for isolating circulating tumor cells (CTCs) suffer from poor purity and yield and require fixatives that preclude the collection of viable cells for longitudinal analyses of biological function. Antigen specific lysis (ASL) is a rapid, high-purity method of cell isolation based on targeted protective coatings on antigen-presenting cells and lysis depletion of unprotected antigen-negative cells. In ASL, photoinitiators are specifically labeled on cell surfaces that enable subsequent surface-initiated polymerization. Critically, the significant determinants of process yield have yet to be investigated for this emerging technology. In this work, we show that the labeling density of photoinitiators is strongly correlated with the yield of intact cells during ASL by flow cytometry analysis. Results suggest ASL is capable of delivering ∼25% of targeted cells after isolation using traditional antibody labeling approaches. Monomer formulations of two molecular weights of PEG-diacrylate (Mn ∼ 575 and 3500) are examined. The gelation response during ASL polymerization is also investigated via protein microarray analogues on planar glass. Finally, a density threshold of photoinitiator labeling required for protection during lysis is determined for both monomer formulations. These results indicate ASL is a promising technology for high yield CTC isolation for rare-cell function assays and fluid biopsies. PMID:27206735

  14. Surface functionality affects the biodistribution and microglia-targeting of intra-amniotically delivered dendrimers.

    PubMed

    Zhang, Fan; Nance, Elizabeth; Zhang, Zhi; Jasty, Venkatasai; Kambhampati, Siva P; Mishra, Manoj K; Burd, Irina; Romero, Roberto; Kannan, Sujatha; Kannan, Rangaramanujam M

    2016-09-10

    Cerebral Palsy (CP) is a chronic childhood disorder with limited therapeutic options. Maternal intrauterine inflammation/infection is a major risk factor in the pathogenesis of CP. In pre-clinical models, dendrimer-based therapies are viable in postnatal period, attenuating inflammation and improving motor function in vivo. However, treatment to the mother, in the prenatal period, may provide the possibility of preventing/resolving inflammation at early stages. Towards this goal, we used a maternal intrauterine inflammation-induced rabbit model of CP to study fetal-maternal transport and neuroinflammation targeting of intra-amniotically administrated dendrimers with neutral/anionic surface functionality. Our study suggested both hydroxyl-terminated 'neutral' (D-OH) and carboxyl-terminated 'anionic' (D-COOH) Polyamidoamine (PAMAM) dendrimers were absorbed by fetuses and demonstrated bi-directional transport between fetuses and mother. D-OH was more effective in crossing the fetal blood-brain barrier, and targeting activated microglia. The cell-specific targeting was associated with the extent of microglia activation. This study demonstrated intra-amniotically administered hydroxyl PAMAM dendrimers could be an effective drug delivery vehicle for targeting fetal inflammation and preventing subsequent neurologic injury associated with chorioamnionitis.

  15. Surface functionality affects the biodistribution and microglia-targeting of intra-amniotically delivered dendrimers.

    PubMed

    Zhang, Fan; Nance, Elizabeth; Zhang, Zhi; Jasty, Venkatasai; Kambhampati, Siva P; Mishra, Manoj K; Burd, Irina; Romero, Roberto; Kannan, Sujatha; Kannan, Rangaramanujam M

    2016-09-10

    Cerebral Palsy (CP) is a chronic childhood disorder with limited therapeutic options. Maternal intrauterine inflammation/infection is a major risk factor in the pathogenesis of CP. In pre-clinical models, dendrimer-based therapies are viable in postnatal period, attenuating inflammation and improving motor function in vivo. However, treatment to the mother, in the prenatal period, may provide the possibility of preventing/resolving inflammation at early stages. Towards this goal, we used a maternal intrauterine inflammation-induced rabbit model of CP to study fetal-maternal transport and neuroinflammation targeting of intra-amniotically administrated dendrimers with neutral/anionic surface functionality. Our study suggested both hydroxyl-terminated 'neutral' (D-OH) and carboxyl-terminated 'anionic' (D-COOH) Polyamidoamine (PAMAM) dendrimers were absorbed by fetuses and demonstrated bi-directional transport between fetuses and mother. D-OH was more effective in crossing the fetal blood-brain barrier, and targeting activated microglia. The cell-specific targeting was associated with the extent of microglia activation. This study demonstrated intra-amniotically administered hydroxyl PAMAM dendrimers could be an effective drug delivery vehicle for targeting fetal inflammation and preventing subsequent neurologic injury associated with chorioamnionitis. PMID:27378700

  16. Effects of Ti surface treatments with silane and arginylglycylaspartic acid peptide on bone cell progenitors.

    PubMed

    Chen, Wen-Cheng; Lo, Yang; Chen, Hong-Sen

    2015-09-01

    Achieving optimal aesthetic appearance is a major objective in dental implant design, and the interaction between the materials and the bone cell progenitors is an important factor in the attainment of this objective. In this study, a novel concept was evaluated by varying the surface modifications on titanium (Ti). Different levels of roughness can be attained by machine grinding (M), sand blasting, and acid etching (SLA) of the samples. The behavior of bone cell progenitors (D1) on the surfaces of Ti disks with different surface modifications was investigated. The surfaces of M or SLA disks were silanized (MS or SLAS group) through treatment with silane/Gly-Arg-Gly-Asp-Ser (GRGDS) peptide (MSP or SLASP group) and anchored particles of tetracalcium phosphate (TTCP) on the specimen surfaces (SLA-TTCP group). Physicochemical analysis was performed by metallographic microscopy, scanning electron microscopy, and contact angle analysis. The proliferation and the quantitative alkaline phosphatase (ALP) production of D1 cells on the surface of different sample groups were determined. The SLASP group had a significantly larger D1 cell proliferation than the other groups after 4 and 7 d of incubation (p < 0.05). ALP expression was a very early marker of differentiation, and was the first indication of the increasing number of cells at 7 d of culture. Among the groups in the M substrate series (i.e., M, MS, and MSP) and in the SLA series (i.e., SLA, SLAS, and SLASP), the MSP and SLASP specimens exhibited superior differentiation abilities on respective cultures until day 7 and day 10. A high number of hydrophilic surfaces dominated cell proliferation in the early stage of cell attachment. However, factors affecting the pore structure and the surface morphology can improve cell proliferation and differentiation. According to analyses of proliferation and ALP expression of bone cell progenitors D1, the original SLA implant surface can be improved with surface treatment

  17. Actin polymerization and intracellular solvent flow in cell surface blebbing

    PubMed Central

    1995-01-01

    The cortical actin gel of eukaryotic cells is postulated to control cell surface activity. One type of protrusion that may offer clues to this regulation are the spherical aneurysms of the surface membrane known as blebs. Blebs occur normally in cells during spreading and alternate with other protrusions, such as ruffles, suggesting similar protrusive machinery is involved. We recently reported that human melanoma cell lines deficient in the actin filament cross-linking protein, ABP-280, show prolonged blebbing, thus allowing close study of blebs and their dynamics. Blebs expand at different rates of volume increase that directly predict the final size achieved by each bleb. These rates decrease as the F-actin concentration of the cells increase over time after plating on a surface, but do so at lower concentrations in ABP-280 expressing cells. Fluorescently labeled actin and phalloidin injections of blebbing cells indicate that a polymerized actin structure is not present initially, but appears later and is responsible for stopping further bleb expansion. Therefore, it is postulated that blebs occur when the fluid-driven expansion of the cell membrane is sufficiently rapid to initially outpace the local rate of actin polymerization. In this model, the rate of intracellular solvent flow driving this expansion decreases as cortical gelation is achieved, whether by factors such as ABP-280, or by concentrated actin polymers alone, thereby leading to decreased size and occurrence of blebs. Since the forces driving bleb extension would always be present in a cell, this process may influence other cell protrusions as well. PMID:7790356

  18. Only scratching the cell surface: extracellular signals in cerebrum development.

    PubMed

    Hébert, Jean M

    2013-08-01

    Numerous roles have been identified for extracellular signals such as Fibroblast Growth Factors (FGFs), Transforming Growth Factor-βs (TGFβs), Wingless-Int proteins (WNTs), and Sonic Hedgehog (SHH) in assigning fates to cells during development of the cerebrum. However, several fundamental questions remain largely unexplored. First, how does the same extracellular signal instruct precursor cells in different locations or at different stages to adopt distinct fates? And second, how does a precursor cell integrate multiple signals to adopt a specific fate? Answers to these questions require knowing the mechanisms that underlie each cell type's competence to respond to certain extracellular signals. This brief review provides illustrative examples of potential mechanisms that begin to bridge the gap between cell surface and cell fate during cerebrum development.

  19. Cadmium affects mitotically inherited histone modification pathways in mouse embryonic stem cells.

    PubMed

    Gadhia, S R; O'Brien, D; Barile, F A

    2015-12-25

    The fetal basis of adult disease (FeBAD) theorizes that embryonic challenges initiate pathologies in adult life through epigenetic modification of gene expression. In addition, inheritance of H3K27 methylation marks, especially in vitro, is still controversial. Metals, such as Cd, are known to affect differentiation, DNA repair and epigenetic status in mES cells. We tested the premise that Cd exerts differential toxicity in mouse embryonic stem (mES) cells by targeting total histone protein (THP) production early in stem cell development, while affecting H3K27-mono-methylation (H3K27me(1)) in latter stages of differentiation. The inability of mES cells to recover from Cd insult at concentrations greater than IC50 indicates that maximum cytotoxicity occurs during initial hours of exposure. Moreover, as a measure of chromatin stability, low dose acute Cd exposure lowers THP production. The heritable effects of Cd exposure on cell proliferation, chromatin stability and transcription observed through several cell population doublings were detected only during alternate passages on days 3, 7, and 11, presumably due to slower maturation of histone methylation marks. These findings demonstrate a selective disruption of chromatin structure following acute Cd exposure, an effect not seen in developmentally mature cells. Hence, we present that acute Cd toxicity is cumulative and disrupts DNA repair, while concurrently affecting cell cycle progression, chromatin stability and transcriptional state in mES cells.

  20. Monoclonal antibody to human endothelial cell surface internalization and liposome delivery in cell culture.

    PubMed

    Trubetskaya, O V; Trubetskoy, V S; Domogatsky, S P; Rudin, A V; Popov, N V; Danilov, S M; Nikolayeva, M N; Klibanov, A L; Torchilin, V P

    1988-02-01

    A monoclonal antibody (mAb), E25, is described that binds to the surface of cultured human endothelial cells. Upon binding E25 is rapidly internalized and digested intracellularly. Selective liposome targeting to the surface of the cells is performed using a biotinylated E25 antibody and an avidin-biotin system. Up to 30% of the cell-adherent liposomal lipid is internalized.

  1. Surface enhanced Raman spectroscopy measurements of MCF7 cells adhesion in confined micro-environments

    NASA Astrophysics Data System (ADS)

    De Vitis, Stefania; Coluccio, Maria Laura; Gentile, Francesco; Malara, Natalia; Perozziello, Gerardo; Dattola, Elisabetta; Candeloro, Patrizio; Di Fabrizio, Enzo

    2016-01-01

    Undoubtedly cells can perceive the external environment, not only from a biochemical point of view with the related signalling pathways, but also from a physical and topographical perspective. In this sense controlled three dimensional micro-structures as well as patterns at the nano-scale can affect and guide the cell evolution and proliferation, due to the fact that the surrounding environment is no longer isotropic (like the flat surfaces of standard cell culturing) but possesses well defined symmetries and anisotropies. In this work regular arrays of silicon micro-pillars with hexagonal arrangement are used as culturing substrates for MCF-7 breast cancer cells. The characteristic size and spacing of the pillars are tens of microns, comparable with MCF-7 cell dimensions and then well suited to induce acceptable external stimuli. It is shown that these cells strongly modify their morphology for adapting themselves to the micro-structured landscape, by means of protrusions from the main body of the cell. Scanning electron microscopy along with both Raman micro-spectroscopy and surface enhanced Raman spectroscopy are used for topographical and biochemical studies of the new cell arrangement. We have revealed that single MCF-7 cells exploit their capability to produce invadopodia, usually generated to invade the neighboring tissue in metastatic activity, for spanning and growing across separate pillars.

  2. The effect of tendon surface treatment on cell attachment for potential enhancement of tendon graft healing: an ex vivo model.

    PubMed

    Hashimoto, Takahiro; Sun, Yu-Long; An, Kai-Nan; Amadio, Peter C; Zhao, Chunfeng

    2012-12-01

    For both tendon allografts and autografts, the surface, initially optimized for gliding, may not be ideal to facilitate tissue integration for graft healing to host tendon or bone. As a prelude to studying tendon-bone integration, we investigated the effect of surface treatments with trypsin or mechanical abrasion on cell attachment to the tendon surface in a canine ex vivo intrasynovial tendon tissue culture model. Intrasynovial tendon allograft surfaces were seeded with cells after the following treatments: (1) no treatment, (2) mechanical abrasion, (3) trypsin, and (4) abrasion and trypsin. The area covered by cells was determined using confocal laser microscopy at one and two weeks. Results were compared to untreated extrasynovial tendon. Additional tendons were characterized with scanning electron microscopy. Tendons with trypsin treatment had significantly more surface coverage with cells than the other groups, after both one and two weeks of culture. In terms of the cellular shape and size, cells on tendons with trypsin treatment spread more and were more polygonal in shape, whereas tendons with mechanical abrasion with/without trypsin treatment contained smaller, more spindle-like cells. Surface roughening can affect cell behavior with topographical stimulation. Trypsin surface digestion exposes a mesh-like structure on the tendon surface, which could enhance cell adherence and, possibly, tendon/bone healing.

  3. Processes affecting the transport of Cryptosporidium parvum and other persistent pathogens in surface- and ground-waters

    NASA Astrophysics Data System (ADS)

    Packman, A. I.; Lau, B. L.; Harter, T.; Atwill, E. R.

    2007-12-01

    Waterborne diseases are transmitted through numerous environmental pathways, and their migration is strongly mediated by interaction with a wide variety of sediments and other natural materials during transport. Here we provide an overview of factors that affect the fate of persistent water-borne pathogens, focusing particularly on the zoonotic pathogen Cryptosporidium parvum as an example. While individual microbial cells are both small and have low specific gravity, suggesting that they should be highly mobile and remain suspended for long periods of time, attachment to a variety of background materials can substantially reduce pathogen mobility. Cryptosporidium oocysts readily associate with both inorganic and organic particles, resulting in the formation of aggregates. This process tends to increase the effective settling velocity of C. parvum in surface waters. Similarly, pathogens readily become associated with the solid matrix during transport in groundwater, resulting in removal by filtration. However, this process is reversible with C. parvum, resulting in a slow long-term release following the initial deposition. Pathogens also become associated with biofilms, which are surface-attached communities of microorganisms in a gelatinous matrix. The presence of biofilms increases the immobilization and retention of Cryptosporidium on solid surfaces. All of these processes influence pathogen transmission in surface waters such as rivers and water-supply canals. In these environments, pathogens can be immobilized by deposition into stable sediment beds by a combination of gravitational sedimentation and advection into pore waters followed by subsurface filtration. Association with background suspended matter tends to increase pathogen deposition by sedimentation, and the presence of benthic (sedimentary) biofilms also tends to increase pathogen retention. For pathogens that remain viable for long periods of time in natural aquatic systems, as is the case with

  4. Surface reactivity and cell responses to chrysotile asbestos nanofibers.

    PubMed

    Turci, Francesco; Colonna, Massimiliano; Tomatis, Maura; Mantegna, Stefano; Cravotto, Giancarlo; Gulino, Giulia; Aldieri, Elisabetta; Ghigo, Dario; Fubini, Bice

    2012-04-16

    High aspect-ratio nanomaterials (HARNs) have recently attracted great attention from nanotoxicologists because of their similarity to asbestos. However, the actual risk associated with the exposure to nanosized asbestos, which escapes most regulations worldwide, is still unknown. Nanometric fibers of chrysotile asbestos have been prepared from two natural sources to investigate whether nanosize may modulate asbestos toxicity and gain insight on the hazard posed by naturally occurring asbestos, which may be defined as HARNs because of their dimensions. Power ultrasound was used to obtain nanofibers from two different chrysotile specimens, one from the dismissed asbestos mine in Balangero (Italian Western Alps) and the other from a serpentine outcrop in the Italian Central Alps. Electron microscopy, X-ray diffraction, and fluorescence spectroscopy revealed that the procedure does not affect mineralogical and chemical composition. Surface reactions related to oxidative stress, free radical generation, bioavailability of iron, and antioxidant depletion, revealed a consistent reduction in reactivity upon reduction in size. When tested on A549 human epithelial cells, the pristine but not the nanosized fibers proved cytotoxic (LDH release), induced NO production, and caused lipid peroxidation. However, nanofibers still induced some toxicity relevant oxidative stress activity (ROS production) in a dose-dependent fashion. The reduction in length and a lack of poorly coordinated bioavailable iron in nanochrysotile may explain this behavior. The present study provides a one-step procedure for the preparation of a homogeneous batch of natural asbestos nanofibers and shows how a well-known toxic material might not necessarily become more toxic than its micrometric counterpart when reduced to the nanoscale.

  5. Mesenchymal stem cell adhesion but not plasticity is affected by high substrate stiffness

    NASA Astrophysics Data System (ADS)

    Kal Van Tam, Janice; Uto, Koichiro; Ebara, Mitsuhiro; Pagliari, Stefania; Forte, Giancarlo; Aoyagi, Takao

    2012-12-01

    The acknowledged ability of synthetic materials to induce cell-specific responses regardless of biological supplies provides tissue engineers with the opportunity to find the appropriate materials and conditions to prepare tissue-targeted scaffolds. Stem and mature cells have been shown to acquire distinct morphologies in vitro and to modify their phenotype when grown on synthetic materials with tunable mechanical properties. The stiffness of the substrate used for cell culture is likely to provide cells with mechanical cues mimicking given physiological or pathological conditions, thus affecting the biological properties of cells. The sensitivity of cells to substrate composition and mechanical properties resides in multiprotein complexes called focal adhesions, whose dynamic modification leads to cytoskeleton remodeling and changes in gene expression. In this study, the remodeling of focal adhesions in human mesenchymal stem cells in response to substrate stiffness was followed in the first phases of cell-matrix interaction, using poly-ɛ-caprolactone planar films with similar chemical composition and different elasticity. As compared to mature dermal fibroblasts, mesenchymal stem cells showed a specific response to substrate stiffness, in terms of adhesion, as a result of differential focal adhesion assembly, while their multipotency as a bulk was not significantly affected by matrix compliance. Given the sensitivity of stem cells to matrix mechanics, the mechanobiology of such cells requires further investigations before preparing tissue-specific scaffolds.

  6. Acid base properties of cyanobacterial surfaces. II: Silica as a chemical stressor influencing cell surface reactivity

    NASA Astrophysics Data System (ADS)

    Lalonde, S. V.; Smith, D. S.; Owttrim, G. W.; Konhauser, K. O.

    2008-03-01

    Bacteria grow in complex solutions where the adsorption of aqueous species and nucleation of mineral phases on the cell surface may interfere with membrane-dependent homeostatic functions. While previous investigations have provided evidence that bacteria may alter their surface chemical properties in response to environmental stimuli, to our knowledge no effort has been made to evaluate surface compositional changes resulting from non-nutritional chemical stresses within a quantitative framework applicable to surface complexation modeling. We consider here the influence of exposure to silica on cyanobacterial surface chemistry, particularly in light of the propensity for cyanobacteria to become silicified in geothermal environments. Using data modeled from over 50 potentiometric titrations of the unsheathed cyanobacterium Anabaena sp. strain PCC 7120, we find that both abiotic geochemical and biotic biochemical-assimilatory factors have important and different effects on cell surface chemistry. Changes in functional group distribution that resulted from growth by different nitrogen assimilation pathways were greatest in the absence of dissolved silica and less important in its presence. Furthermore, out of the three nitrogen assimilation pathways investigated, in terms of surface functional group distribution, nitrate-reducing cultures were least sensitive, and ammonium-assimilating cultures were most sensitive, to changes in media silica concentration. When functional group distributions were plotted as a function of silica concentration, it appears that, with higher silica concentrations, basic groups (p Ka > 7) increase in concentration relative to acidic groups (p Ka < 7), and the total ligand densities (on a per-weight basis) decreased. The results imply a decrease in both the magnitude and density of surface charge as the net result of growth at high silica concentrations. Thus, Anabaena sp. appears to actively respond to growth in silicifying solutions by

  7. Simplified fabrication of back surface electric field silicon cells and novel characteristics of such cells

    NASA Technical Reports Server (NTRS)

    Mandelkorn, J.; Lamneck, J. H., Jr.

    1972-01-01

    An investigation of the characteristics and behavior of 10 ohm-cm silicon cells having abnormally high open-circuit voltages was made. The cells studied were made by a new, highly simplified, contact fabrication process which creates both a contact and a thin electric field region at the cell back surface without the need for phosphorus layer removal. These cells had open-circuit voltages of about 0.58 V and their performance as a function of thickness, temperature, and 1 MeV electron irradiation is detailed. The study showed that 10 ohm-cm back-surface-field cells can have the high initial efficiencies and desirable temperature behavior of low resistivity cells. Thin back-surface-field cells were made and showed, in addition, much greater radiation damage resistance. A mechanism is proposed to explain the results.

  8. Simplified fabrication of back surface electric field silicon cells and novel characteristics of such cells.

    NASA Technical Reports Server (NTRS)

    Mandelkorn, J.; Lamneck, J. H., Jr.

    1972-01-01

    An investigation of the characteristics and behavior of 10 ohm-cm silicon cells having abnormally high open-circuit voltages was made. The cells studied were made by a new, highly simplified, contact fabrication process which creates both a contact and a thin electric field region at the cell back surface without the need for phosphorus layer removal. These cells had open-circuit voltages of about 0.58 V and their performance as a function of thickness, temperature, and 1 MeV electron irradiation is detailed. The study showed that 10 ohm-cm back-surface-field cells can have the high initial efficiencies and desirable temperature behavior of low resistivity cells. Thin back-surface-field cells were made and showed, in addition, much greater radiation damage resistance. A mechanism is proposed to explain the results.

  9. Marine organic geochemistry in industrially affected coastal areas in Greece: Hydrocarbons in surface sediments

    NASA Astrophysics Data System (ADS)

    Hatzianestis, Ioannis

    2015-04-01

    Hydrocarbons are abundant components of the organic material in coastal zones. Their sources are mainly anthropogenic, but several natural ones have also been recognized. Among hydrocarbons, the polycyclic aromatic ones (PAHs) have received special attention since they considered as hazardous environmental chemicals and are included in priority pollutant lists. The purpose of this study was to investigate the distribution, sources and transport pathways of hydrocarbons in marine areas in Greece directly influenced from the operation of major industrial units in the coastal zone by using a molecular marker approach, characteristic compositional patterns and related indices and also to evaluate their potential toxicity. Thirty two surface sediment samples were collected from three marine areas: a) Antikyra bay in Korinthiakos gulf, affected from the operation of an alumina and production plant b) Larymna bay in Noth Evoikos, affected from the operation of a nickel production plant and c) Aliveri bay in South Evoikos Gulf, affected from a cement production plant. In all the studied areas aquaculture and fishing activities have been also developed in the coastal zone. High aliphatic hydrocarbon (AHC) concentrations (~500 μg/g), indicating significant petroleum related inputs, were measured only in Antikyra bay. In all the other samples, AHC values were below 100 μg/g. N-alkanes were the most prominent resolved components (R) with an elevated odd to even carbon number preference, revealing the high importance of terrestrial inputs in the study areas. The unresolved complex mixture (UCM) was the major component of the aliphatic fraction (UCM/R > 4), indicating a chronic oil pollution. A series of hopanes were also identified, with patterns characteristic of oil-derived hydrocarbons, further confirming the presence of pollutant inputs from fossil fuel products. Extremely high PAH concentrations (> 100,000 ng/g) were found in the close vicinity of the alumina production

  10. Bone morphogenetic protein Smads signaling in mesenchymal stem cells affected by osteoinductive calcium phosphate ceramics.

    PubMed

    Tang, Zhurong; Wang, Zhe; Qing, Fangzhu; Ni, Yilu; Fan, Yujiang; Tan, Yanfei; Zhang, Xingdong

    2015-03-01

    Porous calcium phosphate ceramics (CaP ceramics) could induce ectopic bone formation which was regulated by various signal molecules. In this work, bone marrow mesenchymal stem cells (MSCs) were cultured on the surface of osteoinductive hydroxyapatite (HA) and biphasic calcium phosphate (BCP) ceramics in comparison with control (culture plate) for up to 14 days to detect the signal molecules which might be affected by the CaP ceramics. Without adding osteogenic factors, MSCs cultured on HA and BCP both expressed higher Runx2, Osterix, collagen type I, osteopontin, bone sialoprotein, and osteocalcin at various stages compared with control, thus confirmed the osteoblastic differentiation of MSCs. Later study demonstrated the messenger RNA level of bone morphogenetic protein 2 (BMP2) and BMP4 were also significantly enhanced by HA and BCP. Furthermore, Smad1, 4, 5, and Dlx5, the main molecules in the BMP/Smads signaling pathway, were upregulated by HA and BCP. Moreover, the higher expression of Smads and BMP2, 4 in BCP over HA, corresponded to the better performance of BCP in stimulating in vitro osteoblastic differentiation of MSCs. This was in accordance with the better osteoinductivity of BCP over HA in vivo. Altogether, these results implied that the CaP ceramics may initiate the osteoblastic differentiation of MSCs by influencing the expression of molecules in BMP/Smads pathway.

  11. Cell surface energy, contact angles and phase partition. II. Bacterial cells in biphasic aqueous mixtures.

    PubMed

    Gerson, D F; Akit, J

    1980-11-01

    Partition coefficients in biphasic mixtures of poly(ethylene glycol) and Dextran are compared to cell surface energies obtained from contact angles of each liquid phase on cell layers. Linear relationships are observed between these two independent measurements for a variety of bacterial cells. The results demonstrate the importance of interfacial phenomena and contact angles in the phase-partition process. PMID:6159003

  12. Rare TREM2 variants associated with Alzheimer's disease display reduced cell surface expression.

    PubMed

    Sirkis, Daniel W; Bonham, Luke W; Aparicio, Renan E; Geier, Ethan G; Ramos, Eliana Marisa; Wang, Qing; Karydas, Anna; Miller, Zachary A; Miller, Bruce L; Coppola, Giovanni; Yokoyama, Jennifer S

    2016-09-02

    Rare variation in TREM2 has been associated with greater risk for Alzheimer's disease (AD). TREM2 encodes a cell surface receptor expressed on microglia and related cells, and the R47H variant associated with AD appears to affect the ability of TREM2 to bind extracellular ligands. In addition, other rare TREM2 mutations causing early-onset neurodegeneration are thought to impair cell surface expression. Using a sequence kernel association (SKAT) analysis in two independent AD cohorts, we found significant enrichment of rare TREM2 variants not previously characterized at the protein level. Heterologous expression of the identified variants showed that novel variants S31F and R47C displayed significantly reduced cell surface expression. In addition, we identified rare variant R136Q in a patient with language-predominant AD that also showed impaired surface expression. The results suggest rare TREM2 variants enriched in AD may be associated with altered TREM2 function and that AD risk may be conferred, in part, from altered TREM2 surface expression.

  13. Rare TREM2 variants associated with Alzheimer's disease display reduced cell surface expression.

    PubMed

    Sirkis, Daniel W; Bonham, Luke W; Aparicio, Renan E; Geier, Ethan G; Ramos, Eliana Marisa; Wang, Qing; Karydas, Anna; Miller, Zachary A; Miller, Bruce L; Coppola, Giovanni; Yokoyama, Jennifer S

    2016-01-01

    Rare variation in TREM2 has been associated with greater risk for Alzheimer's disease (AD). TREM2 encodes a cell surface receptor expressed on microglia and related cells, and the R47H variant associated with AD appears to affect the ability of TREM2 to bind extracellular ligands. In addition, other rare TREM2 mutations causing early-onset neurodegeneration are thought to impair cell surface expression. Using a sequence kernel association (SKAT) analysis in two independent AD cohorts, we found significant enrichment of rare TREM2 variants not previously characterized at the protein level. Heterologous expression of the identified variants showed that novel variants S31F and R47C displayed significantly reduced cell surface expression. In addition, we identified rare variant R136Q in a patient with language-predominant AD that also showed impaired surface expression. The results suggest rare TREM2 variants enriched in AD may be associated with altered TREM2 function and that AD risk may be conferred, in part, from altered TREM2 surface expression. PMID:27589997

  14. Surface plasmon resonance imaging of cells and surface-associated fibronectin

    PubMed Central

    Peterson, Alexander W; Halter, Michael; Tona, Alessandro; Bhadriraju, Kiran; Plant, Anne L

    2009-01-01

    Background A critical challenge in cell biology is quantifying the interactions of cells with their extracellular matrix (ECM) environment and the active remodeling by cells of their ECM. Fluorescence microscopy is a commonly employed technique for examining cell-matrix interactions. A label-free imaging method would provide an alternative that would eliminate the requirement of transfected cells and modified biological molecules, and if collected nondestructively, would allow long term observation and analysis of live cells. Results Using surface plasmon resonance imaging (SPRI), the deposition of protein by vascular smooth muscle cells (vSMC) cultured on fibronectin was quantified as a function of cell density and distance from the cell periphery. We observed that as much as 120 ng/cm2 of protein was deposited by cells in 24 h. Conclusion SPRI is a real-time, low-light-level, label-free imaging technique that allows the simultaneous observation and quantification of protein layers and cellular features. This technique is compatible with live cells such that it is possible to monitor cellular modifications to the extracellular matrix in real-time. PMID:19245706

  15. Fine Surface Images That Reflect Cytoskeletal Structures in Cultured Glial Cells by Atomic Force Microscopy

    NASA Astrophysics Data System (ADS)

    Yamane, Yukako; Hatakeyama, Dai; Tojima, Takuro; Kawabata, Kazushige; Ushiki, Tatsuo; Ogura, Shigeaki; Abe, Kazuhiro; Ito, Etsuro

    1998-06-01

    The morphology of cultured glial cells was examined using a combination of atomic force microscopy (AFM) and immunofluorescence staining for cytoskeletons. The meshwork of type-1 astrocytes consisted of thick longitudinal and thin lateral lines on the cell surfaces observed by AFM; the former lines were confirmed to be reflections of actin filaments. The astrocytic processes of type-2 astrocytes were observed to be rugged on AFM. These structures were mainly affected by microtubules. Immunofluorescence imaging of microglia revealed that actin filaments and microtubules were arranged radially and wavily along the cell edge, respectively. AFM could detect these radial and wavy structures clearly. These results show that AFM can provide information on the cytoskeletons of glial cells, indicating that AFM is a useful tool for the morphological characterization of cells.

  16. Aquaporin-1 plays important role in proliferation by affecting cell cycle progression.

    PubMed

    Galán-Cobo, Ana; Ramírez-Lorca, Reposo; Toledo-Aral, Juan José; Echevarría, Miriam

    2016-01-01

    Aquaporin-1 (AQP1) has been associated with tumor development. Here, we investigated how AQP1 may affect cell proliferation. The proliferative rate of adult carotid body (CB) cells, known to proliferate under chronic hypoxia, was analyzed in wild-type (AQP1(+/+) ) and knock out (AQP1(-/-) ) mice, maintained in normoxia or exposed to hypoxia while BrdU was administered. Fewer numbers of total BrdU(+) and TH-BrdU(+) cells were observed in AQP1(-/-) mice, indicating a role for AQP1 in CB proliferation. Then, by flow cytometry, cell cycle state and proliferation of cells overexpressing AQP1 were compared to those of wild-type cells. In the AQP1-overexpressing cells, we observed higher cell proliferation and percentages of cells in phases S and G2/M and fewer apoptotic cells after nocodazole treatment were detected by annexin V staining. Also in these cells, proteomic assays showed higher expression of cyclin D1 and E1 and microarray analysis revealed changes in many cell proliferation-related molecules, including, Zeb 2, Jun, NF-kβ, Cxcl9, Cxcl10, TNF, and the TNF receptor. Overall, our results indicate that the presence of AQP1 modifies the expression of key cell cycle proteins apparently related to increases in cell proliferation. This contributes to explaining the presence of AQP1 in many different tumors.

  17. Dynamics between fruit cuticles and surface microflora can affect sanitizing methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilms are communities of microorganisms held together by substances such as polysaccharides which form on surfaces. These communities do not need to be on living tissue but form on any available surface such as rocks in a stream, interior of pipes and on teeth. On surfaces, including fruit, these...

  18. Emergence of an Apical Epithelial Cell Surface In Vivo.

    PubMed

    Sedzinski, Jakub; Hannezo, Edouard; Tu, Fan; Biro, Maté; Wallingford, John B

    2016-01-11

    Epithelial sheets are crucial components of all metazoan animals, enclosing organs and protecting the animal from its environment. Epithelial homeostasis poses unique challenges, as addition of new cells and loss of old cells must be achieved without disrupting the fluid-tight barrier and apicobasal polarity of the epithelium. Several studies have identified cell biological mechanisms underlying extrusion of cells from epithelia, but far less is known of the converse mechanism by which new cells are added. Here, we combine molecular, pharmacological, and laser-dissection experiments with theoretical modeling to characterize forces driving emergence of an apical surface as single nascent cells are added to a vertebrate epithelium in vivo. We find that this process involves the interplay between cell-autonomous actin-generated pushing forces in the emerging cell and mechanical properties of neighboring cells. Our findings define the forces driving this cell behavior, contributing to a more comprehensive understanding of epithelial homeostasis. PMID:26766441

  19. Effect of Substrate and Cell Surface Hydrophobicity on Phosphate Utilization in Bacteria

    PubMed Central

    Lemke, M. J.; Churchill, P. F.; Wetzel, R. G.

    1995-01-01

    We measured the rates of utilization of hydrophobic and hydrophilic phosphate compounds in gram-negative bacteria with different surface hydrophobicities, isolated from wetland habitats. Three hydrophobic and two hydrophilic bacterial species were selected for study by measuring cell adherence to hydrocarbons. The bacteria were grown under phosphorus-limited conditions with P(infi), hydrophilic (beta)-glycerophosphate, or hydrophobic phosphatidic acid as the phosphate source. Hydrophilic bacteria grew most rapidly on P(infi), followed by (beta)-glycerophosphate. Phosphatidic acid did not support growth or did so at a much later time (40 h) than did the other phosphate treatments. Although all hydrophobic species grew well on these substrates, the rate of growth of two Acinetobacter baumannii isolates on phosphatidic acid exceeded the rate of growth on phosphate or (beta)-glycerophosphate. A membrane phospholipid and lipopolysaccharide were used as a source of phosphorus by hydrophobic species, whereas hydrophilic species could not use the membrane phospholipids and used lipopolysaccharide to a lesser extent. Besides hydrophobic interaction between cells and substrate, phosphatase activity, which was cell bound in hydrophilic species but 30 to 50% unbound in hydrophobic species, affected cell growth. Dialyzed culture supernatant containing phosphatase from hydrophobic species increased the phosphate availability to hydrophilic species. Additionally, cellular extracts from a hydrophilic species, when added to hydrophilic cells, permitted growth on hydrophobic phosphate sources. Naturally occurring amphiphilic humic acids affected the utilization of P(infi) and (beta)-glycerophosphate in bacteria with hydrophilic surfaces but did not affect hydrophobic bacteria. Our results indicate that hydrophobic phosphate sources can be used by bacteria isolated from aquatic environments as the sole phosphorus source for growth. This utilization, in part, appears to be related to

  20. Heat-transfer resistance measurement method (HTM)-based cell detection at trace levels using a progressive enrichment approach with highly selective cell-binding surface imprints.

    PubMed

    Bers, Karolien; Eersels, Kasper; van Grinsven, Bart; Daemen, Mat; Bogie, Jeroen F J; Hendriks, Jerome J A; Bouwmans, Evelien E; Püttmann, Christiane; Stein, Christoph; Barth, Stefan; Bos, Gerard M J; Germeraad, Wilfred T V; De Ceuninck, Ward; Wagner, Patrick

    2014-04-01

    Surface-imprinted polymers allow for specific cell detection based on simultaneous recognition of the cell shape, cell size, and cell membrane functionalities by macromolecular cell imprints. In this study, the specificity of detection and the detection sensitivity for target cells within a pool of non-target cells were analyzed for a cell-specific surface-imprinted polymer combined with a heat-transfer-based read-out technique (HTM). A modified Chinese hamster ovarian cell line (CHO-ldlD) was used as a model system on which the transmembrane protein mucin-1 (MUC1) could be excessively expressed and for which the occurrence of MUC1 glycosylation could be controlled. In specific cancer cells, the overexpressed MUC1 protein typically shows an aberrant apical distribution and glycosylation. We show that surface-imprinted polymers discriminate between cell types that (1) only differ in the expression of a specific membrane protein (MUC1) or (2) only differ in the membrane protein being glycosylated or not. Moreover, surface-imprinted polymers of cells carrying different glycoforms of the same membrane protein do target both types of cells. These findings illustrate the high specificity of cell detection that can be reached by the structural imprinting of cells in polymer layers. Competitiveness between target and non-target cells was proven to negatively affect the detection sensitivity of target cells. Furthermore, we show that the detection sensitivity can be increased significantly by repetitively exposing the surface to the sample and eliminating non-specifically bound cells by flushing between consecutive cell exposures.

  1. Endocrine disrupting chemicals affect the adipogenic differentiation of mesenchymal stem cells in distinct ontogenetic windows

    SciTech Connect

    Biemann, Ronald; Navarrete Santos, Anne; Navarrete Santos, Alexander; Riemann, Dagmar; Knelangen, Julia; Blueher, Matthias; Koch, Holger; Fischer, Bernd

    2012-01-13

    Highlights: Black-Right-Pointing-Pointer Endocrine disrupting chemicals affect adipogenesis in mesenchymal stem cells (MSC). Black-Right-Pointing-Pointer The adipogenic impact depends strongly on the window of exposure. Black-Right-Pointing-Pointer Bisphenol A reduces the potential of MSC to differentiate into adipocytes. Black-Right-Pointing-Pointer DEHP and TBT trigger the adipogenic differentiation of mesenchymal stem cells. Black-Right-Pointing-Pointer BPA, DEHP and TBT did not affect adipogenesis in embryonic stem cells. -- Abstract: Endocrine disrupting chemicals (EDC) like bisphenol A (BPA), bis(2-ethylhexyl)phthalate (DEHP) and tributyltin (TBT) are ubiquitously present in the environment and in human tissues. They bind to nuclear hormone receptors and affect cellular and developmental processes. In this study, we show that BPA, DEHP and TBT affect the adipogenic differentiation of murine mesenchymal stem cells (MSC, C3H/10T1/2) in a concentration-, stage- and compound-specific manner. C3H/10T1/2 cells and embryonic stem cells (CGR8) were exposed to BPA, DEHP or TBT at different stages of cell determination and differentiation (undifferentiated growth, adipogenic induction and terminal adipogenic differentiation). The final amount of differentiated adipocytes, cellular triglyceride content and mRNA expression of adipogenic marker genes (adiponectin, FABP4, PPAR{gamma}2, LPL) were quantified and compared with corresponding unexposed cells. BPA (10 {mu}M) decreased subsequent adipogenic differentiation of MSC, when cells were exposed during undifferentiated growth. In contrast, DEHP (100 {mu}M) during the hormonal induction period, and TBT (100 nM) in all investigated stages, enhanced adipogenesis. Importantly, exposure of undifferentiated murine embryonic stem cells did not show any effect of the investigated EDC on subsequent adipogenic differentiation.

  2. Annexin A8 controls leukocyte recruitment to activated endothelial cells via cell surface delivery of CD63

    NASA Astrophysics Data System (ADS)

    Poeter, Michaela; Brandherm, Ines; Rossaint, Jan; Rosso, Gonzalo; Shahin, Victor; Skryabin, Boris V.; Zarbock, Alexander; Gerke, Volker; Rescher, Ursula

    2014-04-01

    To enable leukocyte adhesion to activated endothelium, the leukocyte receptor P-selectin is released from Weibel-Palade bodies (WPB) to the endothelial cell surface where it is stabilized by CD63. Here we report that loss of annexin A8 (anxA8) in human umbilical vein endothelial cells (HUVEC) strongly decreases cell surface presentation of CD63 and P-selectin, with a concomitant reduction in leukocyte rolling and adhesion. We confirm the compromised leukocyte adhesiveness in inflammatory-activated endothelial venules of anxA8-deficient mice. We find that WPB of anxA8-deficient HUVEC contain less CD63, and that this is caused by improper transport of CD63 from late multivesicular endosomes to WPB, with CD63 being retained in intraluminal vesicles. Consequently, reduced CD63 cell surface levels are seen following WPB exocytosis, resulting in enhanced P-selectin re-internalization. Our data support a model in which anxA8 affects leukocyte recruitment to activated endothelial cells by supplying WPB with sufficient amounts of the P-selectin regulator CD63.

  3. Annexin A8 controls leukocyte recruitment to activated endothelial cells via cell surface delivery of CD63.

    PubMed

    Poeter, Michaela; Brandherm, Ines; Rossaint, Jan; Rosso, Gonzalo; Shahin, Victor; Skryabin, Boris V; Zarbock, Alexander; Gerke, Volker; Rescher, Ursula

    2014-01-01

    To enable leukocyte adhesion to activated endothelium, the leukocyte receptor P-selectin is released from Weibel-Palade bodies (WPB) to the endothelial cell surface where it is stabilized by CD63. Here we report that loss of annexin A8 (anxA8) in human umbilical vein endothelial cells (HUVEC) strongly decreases cell surface presentation of CD63 and P-selectin, with a concomitant reduction in leukocyte rolling and adhesion. We confirm the compromised leukocyte adhesiveness in inflammatory-activated endothelial venules of anxA8-deficient mice. We find that WPB of anxA8-deficient HUVEC contain less CD63, and that this is caused by improper transport of CD63 from late multivesicular endosomes to WPB, with CD63 being retained in intraluminal vesicles. Consequently, reduced CD63 cell surface levels are seen following WPB exocytosis, resulting in enhanced P-selectin re-internalization. Our data support a model in which anxA8 affects leukocyte recruitment to activated endothelial cells by supplying WPB with sufficient amounts of the P-selectin regulator CD63. PMID:24769558

  4. Structure of a bacterial cell surface decaheme electron conduit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves decaheme cytochromes that are located on the bacterial cell surface at the termini of trans-outer-membrane electron transfer conduits...

  5. Cell surface growth in Escherichia coli: distribution of matrix protein.

    PubMed Central

    Begg, K J

    1978-01-01

    Autoradiography of cell envelope "ghosts" from Escherichia coli was used to demonstrate that newly synthesized molecules of "matrix" protein are inserted at random locations over the entire surface of the outer membrane and that, once inserted, these molecules are not thereafter conserved in any fixed spatial location. Images PMID:355219

  6. Multijunction Solar Cells Optimized for the Mars Surface Solar Spectrum

    NASA Technical Reports Server (NTRS)

    Edmondson, Kenneth M.; Fetzer, Chris; Karam, Nasser H.; Stella, Paul; Mardesich, Nick; Mueller, Robert

    2007-01-01

    This paper gives an update on the performance of the Mars Exploration Rovers (MER) which have been continually performing for more than 3 years beyond their original 90-day missions. The paper also gives the latest results on the optimization of a multijunction solar cell that is optimized to give more power on the surface of Mars.

  7. Unleashing Cancer Cells on Surfaces Exposing Motogenic IGDQ Peptides.

    PubMed

    Corvaglia, Valentina; Marega, Riccardo; De Leo, Federica; Michiels, Carine; Bonifazi, Davide

    2016-01-20

    Thiolated peptides bearing the Ile-Gly-Asp (IGD) motif, a highly conserved sequence of fibronectin, are used for the preparation of anisotropic self-assembled monolayers (SAM gradients) to study the whole-population migratory behavior of metastatic breast cancer cells (MDA-MB-231 cells). Ile-Gly-Asp-Gln-(IGDQ)-exposing SAMs sustain the adhesion of MDA-MB-231 cells by triggering focal adhesion kinase phosphorylation, similarly to the analogous Gly-Arg-Gly-Asp-(GRGD)-terminating surfaces. However, the biological responses of different cell lines interfaced with the SAM gradients show that only those exposing the IGDQ sequence induce significant migration of MDA-MB-231 cells. In particular, the observed migratory behavior suggests the presence of cell subpopulations associated with a "stationary" or a "migratory" phenotype, the latter determining a considerable cell migration at the sub-cm length scale. These findings are of great importance as they suggest for the first time an active role of biological surfaces exposing the IGD motif in the multicomponent orchestration of cellular signaling involved in the metastatic progression.

  8. Microarrays for the evaluation of cell-biomaterial surface interactions

    NASA Astrophysics Data System (ADS)

    Thissen, H.; Johnson, G.; McFarland, G.; Verbiest, B. C. H.; Gengenbach, T.; Voelcker, N. H.

    2007-01-01

    The evaluation of cell-material surface interactions is important for the design of novel biomaterials which are used in a variety of biomedical applications. While traditional in vitro test methods have routinely used samples of relatively large size, microarrays representing different biomaterials offer many advantages, including high throughput and reduced sample handling. Here, we describe the simultaneous cell-based testing of matrices of polymeric biomaterials, arrayed on glass slides with a low cell-attachment background coating. Arrays were constructed using a microarray robot at 6 fold redundancy with solid pins having a diameter of 375 μm. Printed solutions contained at least one monomer, an initiator and a bifunctional crosslinker. After subsequent UV polymerisation, the arrays were washed and characterised by X-ray photoelectron spectroscopy. Cell culture experiments were carried out over 24 hours using HeLa cells. After labelling with CellTracker ® Green for the final hour of incubation and subsequent fixation, the arrays were scanned. In addition, individual spots were also viewed by fluorescence microscopy. The evaluation of cell-surface interactions in high-throughput assays as demonstrated here is a key enabling technology for the effective development of future biomaterials.

  9. Revealing the fate of cell surface human P-glycoprotein (ABCB1): The lysosomal degradation pathway.

    PubMed

    Katayama, Kazuhiro; Kapoor, Khyati; Ohnuma, Shinobu; Patel, Atish; Swaim, William; Ambudkar, Indu S; Ambudkar, Suresh V

    2015-10-01

    P-glycoprotein (P-gp) transports a variety of chemically dissimilar amphipathic compounds including anticancer drugs. Although mechanisms of P-gp drug transport are widely studied, the pathways involving its internalization are poorly understood. The present study is aimed at elucidating the pathways involved in degradation of cell surface P-gp. The fate of P-gp at the cell surface was determined by biotinylating cell surface proteins followed by flow cytometry and Western blotting. Our data shows that the half-life of endogenously expressed P-gp is 26.7±1.1 h in human colorectal cancer HCT-15 cells. Treatment of cells with Bafilomycin A1 (BafA1) a vacuolar H+ ATPase inhibitor increased the half-life of P-gp at the cell surface to 36.1±0.5 h. Interestingly, treatment with the proteasomal inhibitors MG132, MG115 or lactacystin alone did not alter the half-life of the protein. When cells were treated with both lysosomal and proteasomal inhibitors (BafA1 and MG132), the half-life was further prolonged to 39-50 h. Functional assays done with rhodamine 123 or calcein-AM, fluorescent substrates of P-gp, indicated that the transport function of P-gp was not affected by either biotinylation or treatment with BafA1 or proteasomal inhibitors. Immunofluorescence studies done with the antibody against lysosomal marker LAMP1 and the P-gp-specific antibody UIC2 in permeabilized cells indicated that intracellular P-gp is primarily localized in the lysosomal compartment. Our results suggest that the lysosomal degradation system could be targeted to increase the sensitivity of P-gp- expressing cancer cells towards chemotherapeutic drugs.

  10. A molecular smart surface for spatio-temporal studies of cell mobility.

    PubMed

    Lee, Eun-ju; Luo, Wei; Chan, Eugene W L; Yousaf, Muhammad N

    2015-01-01

    Active migration in both healthy and malignant cells requires the integration of information derived from soluble signaling molecules with positional information gained from interactions with the extracellular matrix and with other cells. How a cell responds and moves involves complex signaling cascades that guide the directional functions of the cytoskeleton as well as the synthesis and release of proteases that facilitate movement through tissues. The biochemical events of the signaling cascades occur in a spatially and temporally coordinated manner then dynamically shape the cytoskeleton in specific subcellular regions. Therefore, cell migration and invasion involve a precise but constantly changing subcellular nano-architecture. A multidisciplinary effort that combines new surface chemistry and cell biological tools is required to understand the reorganization of cytoskeleton triggered by complex signaling during migration. Here we generate a class of model substrates that modulate the dynamic environment for a variety of cell adhesion and migration experiments. In particular, we use these dynamic substrates to probe in real-time how the interplay between the population of cells, the initial pattern geometry, ligand density, ligand affinity and integrin composition affects cell migration and growth. Whole genome microarray analysis indicates that several classes of genes ranging from signal transduction to cytoskeletal reorganization are differentially regulated depending on the nature of the surface conditions.

  11. A Molecular Smart Surface for Spatio-Temporal Studies of Cell Mobility

    PubMed Central

    Lee, Eun-ju; Luo, Wei; Chan, Eugene W. L.; Yousaf, Muhammad N.

    2015-01-01

    Active migration in both healthy and malignant cells requires the integration of information derived from soluble signaling molecules with positional information gained from interactions with the extracellular matrix and with other cells. How a cell responds and moves involves complex signaling cascades that guide the directional functions of the cytoskeleton as well as the synthesis and release of proteases that facilitate movement through tissues. The biochemical events of the signaling cascades occur in a spatially and temporally coordinated manner then dynamically shape the cytoskeleton in specific subcellular regions. Therefore, cell migration and invasion involve a precise but constantly changing subcellular nano-architecture. A multidisciplinary effort that combines new surface chemistry and cell biological tools is required to understand the reorganization of cytoskeleton triggered by complex signaling during migration. Here we generate a class of model substrates that modulate the dynamic environment for a variety of cell adhesion and migration experiments. In particular, we use these dynamic substrates to probe in real-time how the interplay between the population of cells, the initial pattern geometry, ligand density, ligand affinity and integrin composition affects cell migration and growth. Whole genome microarray analysis indicates that several classes of genes ranging from signal transduction to cytoskeletal reorganization are differentially regulated depending on the nature of the surface conditions. PMID:26030281

  12. Cell Surface Vimentin Is an Attachment Receptor for Enterovirus 71

    PubMed Central

    Du, Ning; Cong, Haolong; Tian, Hongchao; Zhang, Hua; Zhang, Wenliang; Song, Lei

    2014-01-01

    ABSTRACT Enterovirus 71 (EV71) is a highly transmissible pathogenic agent that causes severe central nervous system diseases in infected infants and young children. Here, we reported that EV71 VP1 protein could bind to vimentin intermediate filaments expressed on the host cell surface. Soluble vimentin or an antibody against vimentin could inhibit the binding of EV71 to host cells. Accompanied with the reduction of vimentin expression on the cell surface, the binding of EV71 to cells was remarkably decreased. Further evidence showed that the N terminus of vimentin is responsible for the interaction between EV71 and vimentin. These results indicated that vimentin on the host cell surface may serve as an attachment site that mediated the initial binding and subsequently increased the infectivity of EV71. IMPORTANCE This study delivers important findings on the roles of vimentin filaments in relation to EV71 infection and provides information that not only improves our understanding of EV71 pathogenesis but also presents us with potentially new strategies for the treatment of diseases caused by EV71 infections. PMID:24623428

  13. Cell Surface Nucleolin Facilitates Enterovirus 71 Binding and Infection

    PubMed Central

    Su, Pei-Yi; Wang, Ya-Fang; Huang, Sheng-Wen; Lo, Yu-Chih; Wang, Ya-Hui; Wu, Shang-Rung; Shieh, Dar-Bin; Wang, Jen-Ren; Lai, Ming-Der

    2015-01-01

    ABSTRACT Because the pathogenesis of enterovirus 71 (EV71) remains mostly ambiguous, identifying the factors that mediate viral binding and entry to host cells is indispensable to ultimately uncover the mechanisms that underlie virus infection and pathogenesis. Despite the identification of several receptors/attachment molecules for EV71, the binding, entry, and infection mechanisms of EV71 remain unclear. Herein, we employed glycoproteomic approaches to identify human nucleolin as a novel binding receptor for EV71. Glycoproteins purified by lectin chromatography from the membrane extraction of human cells were treated with sialidase, followed by immunoprecipitation with EV71 particles. Among the 16 proteins identified by tandem mass spectrometry analysis, cell surface nucleolin attracted our attention. We found that EV71 interacted directly with nucleolin via the VP1 capsid protein and that an antinucleolin antibody reduced the binding of EV71 to human cells. In addition, the knockdown of cell surface nucleolin decreased EV71 binding, infection, and production in human cells. Furthermore, the expression of human nucleolin on the cell surface of a mouse cell line increased EV71 binding and conferred EV71 infection and production in the cells. These results strongly indicate that human nucleolin can mediate EV71 binding to and infection of cells. Our findings also demonstrate that the use of glycoproteomic approaches is a reliable methodology to discover novel receptors for pathogens. IMPORTANCE Outbreaks of EV71 have been reported in Asia-Pacific countries and have caused thousands of deaths in young children during the last 2 decades. The discovery of new EV71-interacting molecules to understand the infection mechanism has become an emergent issue. Hence, this study uses glycoproteomic approaches to comprehensively investigate the EV71-interacting glycoproteins. Several EV71-interacting glycoproteins are identified, and the role of cell surface nucleolin in

  14. Cell-surface markers for colon adenoma and adenocarcinoma

    PubMed Central

    Sewda, Kamini; Coppola, Domenico; Enkemann, Steven; Yue, Binglin; Kim, Jongphil; Lopez, Alexis S.; Wojtkowiak, Jonathan W.; Stark, Valerie E.; Morse, Brian; Shibata, David; Vignesh, Shivakumar; Morse, David L.

    2016-01-01

    Early detection of colorectal cancer (CRC) is crucial for effective treatment. Among CRC screening techniques, optical colonoscopy is widely considered the gold standard. However, it is a costly and invasive procedure with a low rate of compliance. Our long-term goal is to develop molecular imaging agents for the non-invasive detection of CRC by molecular imaging-based colonoscopy using CT, MRI or fluorescence. To achieve this, cell surface targets must be identified and validated. Here, we report the discovery of cell-surface markers that distinguish CRC from surrounding tissues that could be used as molecular imaging targets. Profiling of mRNA expression microarray data from patient tissues including adenoma, adenocarcinoma, and normal gastrointestinal tissues was used to identify potential CRC specific cell-surface markers. Of the identified markers, six were selected for further validation (CLDN1, GPR56, GRM8, LY6G6D/F, SLCO1B3 and TLR4). Protein expression was confirmed by immunohistochemistry of patient tissues. Except for SLCO1B3, diffuse and low expression was observed for each marker in normal colon tissues. The three markers with the greatest protein overexpression were CLDN1, LY6G6D/F and TLR4, where at least one of these markers was overexpressed in 97% of the CRC samples. GPR56, LY6G6D/F and SLCO1B3 protein expression was significantly correlated with the proximal tumor location and with expression of mismatch repair genes. Marker expression was further validated in CRC cell lines. Hence, three cell-surface markers were discovered that distinguish CRC from surrounding normal tissues. These markers can be used to develop imaging or therapeutic agents targeted to the luminal surface of CRC. PMID:26894861

  15. "Race for the Surface": Eukaryotic Cells Can Win.

    PubMed

    Pham, Vy T H; Truong, Vi Khanh; Orlowska, Anna; Ghanaati, Shahram; Barbeck, Mike; Booms, Patrick; Fulcher, Alex J; Bhadra, Chris M; Buividas, Ričardas; Baulin, Vladimir; Kirkpatrick, C James; Doran, Pauline; Mainwaring, David E; Juodkazis, Saulius; Crawford, Russell J; Ivanova, Elena P

    2016-08-31

    With an aging population and the consequent increasing use of medical implants, managing the possible infections arising from implant surgery remains a global challenge. Here, we demonstrate for the first time that a precise nanotopology provides an effective intervention in bacterial cocolonization enabling the proliferation of eukaryotic cells on a substratum surface, preinfected by both live Gram-negative, Pseudomonas aeruginosa, and Gram-positive, Staphylococcus aureus, pathogenic bacteria. The topology of the model black silicon (bSi) substratum not only favors the proliferation of eukaryotic cells but is biocompatible, not triggering an inflammatory response in the host. The attachment behavior and development of filopodia when COS-7 fibroblast cells are placed in contact with the bSi surface are demonstrated in the dynamic study, which is based on the use of real-time sequential confocal imaging. Bactericidal nanotopology may enhance the prospect for further development of inherently responsive antibacterial nanomaterials for bionic applications such as prosthetics and implants.

  16. Role of calcium in growth inhibition induced by a novel cell surface sialoglycopeptide

    NASA Technical Reports Server (NTRS)

    Betz, N. A.; Westhoff, B. A.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    Our laboratory has purified an 18 kDa cell surface sialoglycopeptide growth inhibitor (CeReS-18) from intact bovine cerebral cortex cells. Evidence presented here demonstrates that sensitivity to CeReS-18-induced growth inhibition in BALB-c 3T3 cells is influenced by calcium, such that a decrease in the calcium concentration in the growth medium results in an increase in sensitivity to CeReS-18. Calcium did not alter CeReS-18 binding to its cell surface receptor and CeReS-18 does not bind calcium directly. Addition of calcium, but not magnesium, to CeReS-18-inhibited 3T3 cells results in reentry into the cell cycle. A greater than 3-hour exposure to increased calcium is required for escape from CeReS-18-induced growth inhibition. The calcium ionophore ionomycin could partially mimic the effect of increasing extracellular calcium, but thapsigargin was ineffective in inducing escape from growth inhibition. Increasing extracellular calcium 10-fold resulted in an approximately 7-fold increase in total cell-associated 45Ca+2, while free intracellular calcium only increased approximately 30%. However, addition of CeReS-18 did not affect total cell-associated calcium or the increase in total cell-associated calcium observed with an increase in extracellular calcium. Serum addition induced mobilization of intracellular calcium and influx across the plasma membrane in 3T3 cells, and pretreatment of 3T3 cells with CeReS-18 appeared to inhibit these calcium mobilization events. These results suggest that a calcium-sensitive step exists in the recovery from CeReS-18-induced growth inhibition. CeReS-18 may inhibit cell proliferation through a novel mechanism involving altering the intracellular calcium mobilization/regulation necessary for cell cycle progression.

  17. Microbial cell surface characteristics: Elucidating attachment/detachment using hydrophobicity and electrokinetic measurements

    EPA Science Inventory

    The surface properties of microorganisms play an important role in their behavior within the environment. Electrophoretic mobility and cell surface hydrophobicity of bacterial cells influence their initial interaction with surfaces and mediate their stability within an aqueous su...

  18. Analysing Thermal Response Test Data Affected by Groundwater Flow and Surface Temperature Change

    NASA Astrophysics Data System (ADS)

    Verdoya, Massimo; Imitazione, Gianmario; Chiozzi, Paolo; Orsi, Marco; Armadillo, Egidio

    2014-05-01

    Tests that record the underground temperature variation due to a constant heat injected into a borehole (or extracted from it) by means of a carrier fluid are routinely performed to infer subsurface thermal conductivity and borehole thermal resistance, which are needed to size geothermal heat pump systems. The most popular model to analyse temperature-time curves obtained from these tests is the infinite line source (ILS). This model gives appropriate estimations of thermal parameters only if particular hydro-geological conditions are fulfilled. Several flaws can however affect data interpretation with ILS, which is based on strong assumptions like those of a purely conductive heat transfer regime in a homogeneous medium, no vertical heat flow and infinite length of the borehole. Other drawbacks can arise from the difficulty in the proper thermal insulation of the test equipment, and consequently with oscillations of the carrier fluid temperature due to surface temperature changes. In this paper, we focused on the treatment of thermal response test data when both advection and periodic changes of surface temperature occur. We used a moving line source model to simulate temperature-time signals under different hypothesis of Darcy velocity and thermal properties. A random noise was added to the signal in order to mimic high frequency disturbances, possibly caused by equipment operating conditions and/or geological variability. The subsurface thermal conductivity, the Darcy velocity and the borehole thermal resistance were inferred by minimising the root mean square error between the synthetic dataset and the theoretical model. The optimisation was carried out with the Nelder-Mead algorithm, and thermal and hydraulic properties were determined by iterative reprocessing according to a trial-and-error procedure. The inferred thermal and hydraulic parameters are well consistent with the 'a priory' values, and the presence of noise in the synthetic data does not produce

  19. Catechins Variously Affect Activities of Conjugation Enzymes in Proliferating and Differentiated Caco-2 Cells.

    PubMed

    Lněničková, Kateřina; Procházková, Eliška; Skálová, Lenka; Matoušková, Petra; Bártíková, Hana; Souček, Pavel; Szotáková, Barbora

    2016-01-01

    The knowledge of processes in intestinal cells is essential, as most xenobiotics come into contact with the small intestine first. Caco-2 cells are human colorectal adenocarcinoma that once differentiated, exhibit enterocyte-like characteristics. Our study compares activities and expressions of important conjugation enzymes and their modulation by green tea extract (GTE) and epigallocatechin gallate (EGCG) using both proliferating (P) and differentiated (D) caco-2 cells. The mRNA levels of the main conjugation enzymes were significantly elevated after the differentiation of Caco-2 cells. However, no increase in conjugation enzymes' activities in differentiated cells was detected in comparison to proliferating ones. GTE/EGCG treatment did not affect the mRNA levels of any of the conjugation enzymes tested in either type of cells. Concerning conjugation enzymes activities, GTE/EGCG treatment elevated glutathione S-transferase (GST) activity by approx. 30% and inhibited catechol-O-methyltransferase (COMT) activity by approx. 20% in differentiated cells. On the other hand, GTE as well as EGCG treatment did not significantly affect the activities of conjugation enzymes in proliferating cells. Administration of GTE/EGCG mediated only mild changes of GST and COMT activities in enterocyte-like cells, indicating a low risk of GTE/EGCG interactions with concomitantly administered drugs. However, a considerable chemo-protective effect of GTE via the pronounced induction of detoxifying enzymes cannot be expected as well. PMID:27617982

  20. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells.

    PubMed

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes.

  1. Proteomics and glycoproteomics of pluripotent stem-cell surface proteins.

    PubMed

    Sun, Bingyun

    2015-03-01

    Pluripotent stem cells are a unique cell type with promising potential in regenerative and personalized medicine. Yet the difficulty to understand and coax their seemingly stochastic differentiation and spontaneous self-renewal have largely limited their clinical applications. A call has been made by numerous researchers for a better characterization of surface proteins on these cells, in search of biomarkers that can dictate developmental stages and lineage specifications, and can help formulate mechanistic insight of stem-cell fate choices. In the past two decades, proteomics has gained significant recognition in profiling surface proteins at high throughput. This review will summarize the impact of these studies on stem-cell biology, and discuss the used proteomic techniques. A systematic comparison of all the techniques and their results is also attempted here to help reveal pros, cons, and the complementarity of the existing methods. This awareness should assist in selecting suitable strategies for stem-cell related research, and shed light on technical improvements that can be explored in the future.

  2. Melanoma Affects the Composition of Blood Cell-Derived Extracellular Vesicles

    PubMed Central

    Koliha, Nina; Heider, Ute; Ozimkowski, Tobias; Wiemann, Martin; Bosio, Andreas; Wild, Stefan

    2016-01-01

    Extracellular vesicles (EVs) are specifically loaded with nucleic acids, lipids, and proteins from their parental cell. Therefore, the constitution of EVs reflects the type and status of the originating cell and EVs in melanoma patient’s plasma could be indicative for the tumor. Likewise, EVs might influence tumor progression by regulating immune responses. We performed a broad protein characterization of EVs from plasma of melanoma patients and healthy donors as well as from T cells, B cells, natural killer (NK) cells, monocytes, monocyte-derived dendritic cells (moDCs), and platelets using a multiplex bead-based platform. Using this method, we succeeded in analyzing 58 proteins that were differentially displayed on EVs. Hierarchical clustering of protein intensity patterns grouped EVs according to their originating cell type. The analysis of EVs from stimulated B cells and moDCs revealed the transfer of surface proteins to vesicles depending on the cell status. The protein profiles of plasma vesicles resembled the protein profiles of EVs from platelets, antigen-presenting cells and NK cells as shown by platelet markers, co-stimulatory proteins, and a NK cell subpopulation marker. In comparison to healthy plasma vesicles, melanoma plasma vesicles showed altered signals for platelet markers, indicating a changed vesicle secretion or protein loading of EVs by platelets and a lower CD8 signal that might be associated with a diminished activity of NK cells or T cells. As we hardly detected melanoma-derived vesicles in patient’s plasma, we concluded that blood cells induced the observed differences. In summary, our results question a direct effect of melanoma cells on the composition of EVs in melanoma plasma, but rather argue for an indirect influence of melanoma cells on the vesicle secretion or vesicle protein loading by blood cells. PMID:27507971

  3. Melanoma Affects the Composition of Blood Cell-Derived Extracellular Vesicles.

    PubMed

    Koliha, Nina; Heider, Ute; Ozimkowski, Tobias; Wiemann, Martin; Bosio, Andreas; Wild, Stefan

    2016-01-01

    Extracellular vesicles (EVs) are specifically loaded with nucleic acids, lipids, and proteins from their parental cell. Therefore, the constitution of EVs reflects the type and status of the originating cell and EVs in melanoma patient's plasma could be indicative for the tumor. Likewise, EVs might influence tumor progression by regulating immune responses. We performed a broad protein characterization of EVs from plasma of melanoma patients and healthy donors as well as from T cells, B cells, natural killer (NK) cells, monocytes, monocyte-derived dendritic cells (moDCs), and platelets using a multiplex bead-based platform. Using this method, we succeeded in analyzing 58 proteins that were differentially displayed on EVs. Hierarchical clustering of protein intensity patterns grouped EVs according to their originating cell type. The analysis of EVs from stimulated B cells and moDCs revealed the transfer of surface proteins to vesicles depending on the cell status. The protein profiles of plasma vesicles resembled the protein profiles of EVs from platelets, antigen-presenting cells and NK cells as shown by platelet markers, co-stimulatory proteins, and a NK cell subpopulation marker. In comparison to healthy plasma vesicles, melanoma plasma vesicles showed altered signals for platelet markers, indicating a changed vesicle secretion or protein loading of EVs by platelets and a lower CD8 signal that might be associated with a diminished activity of NK cells or T cells. As we hardly detected melanoma-derived vesicles in patient's plasma, we concluded that blood cells induced the observed differences. In summary, our results question a direct effect of melanoma cells on the composition of EVs in melanoma plasma, but rather argue for an indirect influence of melanoma cells on the vesicle secretion or vesicle protein loading by blood cells. PMID:27507971

  4. Cell differentiation within a yeast colony: metabolic and regulatory parallels with a tumor-affected organism.

    PubMed

    Cáp, Michal; Stěpánek, Luděk; Harant, Karel; Váchová, Libuše; Palková, Zdena

    2012-05-25

    Nutrient sensing and metabolic reprogramming are crucial for metazoan cell aging and tumor growth. Here, we identify metabolic and regulatory parallels between a layered, multicellular yeast colony and a tumor-affected organism. During development, a yeast colony stratifies into U and L cells occupying the upper and lower colony regions, respectively. U cells activate a unique metabolism controlled by the glutamine-induced TOR pathway, amino acid-sensing systems (SPS and Gcn4p) and signaling from mitochondria with lowered respiration. These systems jointly modulate U cell physiology, which adapts to nutrient limitations and utilize the nutrients released from L cells. Stress-resistant U cells share metabolic pathways and other similar characteristics with tumor cells, including the ability to proliferate. L cells behave similarly to stressed and starving cells, which activate degradative mechanisms to provide nutrients to U cells. Our data suggest a nutrient flow between both cell types, resembling the Cori cycle and glutamine-NH(4)(+) shuttle between tumor and healthy metazoan cells.

  5. Surface code—biophysical signals for apoptotic cell clearance

    NASA Astrophysics Data System (ADS)

    Biermann, Mona; Maueröder, Christian; Brauner, Jan M.; Chaurio, Ricardo; Janko, Christina; Herrmann, Martin; Muñoz, Luis E.

    2013-12-01

    Apoptotic cell death and the clearance of dying cells play an important and physiological role in embryonic development and normal tissue turnover. In contrast to necrosis, apoptosis proceeds in an anti-inflammatory manner. It is orchestrated by the timed release and/or exposure of so-called ‘find-me’, ‘eat me’ and ‘tolerate me’ signals. Mononuclear phagocytes are attracted by various ‘find-me’ signals, including proteins, nucleotides, and phospholipids released by the dying cell, whereas the involvement of granulocytes is prevented via ‘stay away’ signals. The exposure of anionic phospholipids like phosphatidylserine (PS) by apoptotic cells on the outer leaflet of the plasma membrane is one of the main ‘eat me’ signals. PS is recognized by a number of innate receptors as well as by soluble bridging molecules on the surface of phagocytes. Importantly, phagocytes are able to discriminate between viable and apoptotic cells both exposing PS. Due to cytoskeleton remodeling PS has a higher lateral mobility on the surfaces of apoptotic cells thereby promoting receptor clustering on the phagocyte. PS not only plays an important role in the engulfment process, but also acts as ‘tolerate me’ signal inducing the release of anti-inflammatory cytokines by phagocytes. An efficient and fast clearance of apoptotic cells is required to prevent secondary necrosis and leakage of intracellular danger signals into the surrounding tissue. Failure or prolongation of the clearance process leads to the release of intracellular antigens into the periphery provoking inflammation and development of systemic inflammatory autoimmune disease like systemic lupus erythematosus. Here we review the current findings concerning apoptosis-inducing pathways, important players of apoptotic cell recognition and clearance as well as the role of membrane remodeling in the engulfment of apoptotic cells by phagocytes.

  6. The biology of NK cells and their receptors affects clinical outcomes after hematopoietic cell transplantation (HCT).

    PubMed

    Foley, Bree; Felices, Martin; Cichocki, Frank; Cooley, Sarah; Verneris, Michael R; Miller, Jeffrey S

    2014-03-01

    Natural killer (NK) cells were first identified for their capacity to reject bone marrow allografts in lethally irradiated mice without prior sensitization. Subsequently, human NK cells were detected and defined by their non-major histocompatibility complex (MHC)-restricted cytotoxicity toward transformed or virally infected target cells. Karre et al. later proposed 'the missing self hypothesis' to explain the mechanism by which self-tolerant cells could kill targets that had lost self MHC class I. Subsequently, the receptors that recognize MHC class I to mediate tolerance in the host were identified on NK cells. These class I-recognizing receptors contribute to the acquisition of function by a dynamic process known as NK cell education or licensing. In the past, NK cells were assumed to be short lived, but more recently NK cells have been shown to mediate immunologic memory to secondary exposures to cytomegalovirus infection. Because of their ability to lyse tumors with aberrant MHC class I expression and to produce cytokines and chemokines upon activation, NK cells may be primed by many stimuli, including viruses and inflammation, to contribute to a graft-versus-tumor effect. In addition, interactions with other immune cells support the therapeutic potential of NK cells to eradicate tumor and to enhance outcomes after hematopoietic cell transplantation.

  7. Haemoglobin synthesis in K562 erythroleukaemia cells is affected by intimate contact with monolayers of various human cell types.

    PubMed

    Zuhrie, S R; Pearson, J D; Wickramasinghe, S N

    1988-01-01

    The haemoglobin content of K562 erythroleukaemia cells was affected by co-culture over monolayers of various human cell types. Haemoglobin synthesis was increased after co-culture with umbilical-cord-derived endothelial cells and most monolayers of bone-marrow-derived macrophages, and inhibited after co-culture with two fibroblast lines, blood-monocyte-derived macrophages, a neuroglial cell line (U-251 MG) and most monolayers of bone-marrow-derived stromal cells. These effects were modified when a thin layer of agar was placed over the monolayers. Cell-free culture media conditioned by all but two of the seven types of monolayer studied inhibited haemoglobin synthesis by K562 cells; those conditioned by blood-monocyte-derived macrophages and two of 11 monolayers of bone-marrow-derived macrophages stimulated haemoglobin synthesis. Thus, the haemoglobin content of K562 cells appeared to be influenced both by intimate contact between K562 cells and the cells of the monolayers and by humoral factors released by the monolayers. The data support the concept that erythroid differentiation is partly dependent on intimate contact between erythroid progenitor cells and microenvironmental cells.

  8. Decreased Zinc Availability Affects Glutathione Metabolism in Neuronal Cells and in the Developing Brain

    PubMed Central

    Omata, Yo; Salvador, Gabriela A.; Oteiza, Patricia I.

    2013-01-01

    A deficit in zinc (Zn) availability can increase cell oxidant production, affect the antioxidant defense system, and trigger oxidant-sensitive signals in neuronal cells. This work tested the hypothesis that a decreased Zn availability can affect glutathione (GSH) metabolism in the developing rat brain and in neuronal cells in culture, as well as the capacity of human neuroblastoma IMR-32 cells to upregulate GSH when challenged with dopamine (DA). GSH levels were low in the brain of gestation day 19 (GD19) fetuses from dams fed marginal Zn diets throughout gestation and in Zn-deficient IMR-32 cells. γ-Glutamylcysteine synthetase (GCL), the first enzyme in the GSH synthetic pathway, was altered by Zn deficiency (ZD). The protein and mRNA levels of the GCL modifier (GCLM) and catalytic (GCLC) subunits were lower in the Zn-deficient GD19 fetal brain and in IMR-32 cells compared with controls. The nuclear translocation of transcription factor nuclear factor (erythroid-derived 2)-like 2, which controls GCL transcription, was impaired by ZD. Posttranslationally, the caspase-3-dependent GCLC cleavage was high in Zn-deficient IMR-32 cells. Cells challenged with DA showed an increase in GCLM and GCLC protein and mRNA levels and a consequent increase in GSH concentration. Although Zn-deficient cells partially upregulated GCL subunits after exposure to DA, GSH content remained low. In summary, results show that a low Zn availability affects the GSH synthetic pathway in neuronal cells and fetal brain both at transcriptional and posttranslational levels. This can in part underlie the GSH depletion associated with ZD and the high sensitivity of Zn-deficient neurons to pro-oxidative stressors. PMID:23377617

  9. Surface modified alginate microcapsules for 3D cell culture

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Wen; Kuo, Chiung Wen; Chueh, Di-Yen; Chen, Peilin

    2016-06-01

    Culture as three dimensional cell aggregates or spheroids can offer an ideal platform for tissue engineering applications and for pharmaceutical screening. Such 3D culture models, however, may suffer from the problems such as immune response and ineffective and cumbersome culture. This paper describes a simple method for producing microcapsules with alginate cores and a thin shell of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) to encapsulate mouse induced pluripotent stem (miPS) cells, generating a non-fouling surface as an effective immunoisolation barrier. We demonstrated the trapping of the alginate microcapsules in a microwell array for the continuous observation and culture of a large number of encapsulated miPS cells in parallel. miPS cells cultured in the microcapsules survived well and proliferated to form a single cell aggregate. Droplet formation of monodisperse microcapsules with controlled size combined with flow cytometry provided an efficient way to quantitatively analyze the growth of encapsulated cells in a high-throughput manner. The simple and cost-effective coating technique employed to produce the core-shell microcapsules could be used in the emerging field of cell therapy. The microwell array would provide a convenient, user friendly and high-throughput platform for long-term cell culture and monitoring.

  10. Establishment of cell surface engineering and its development.

    PubMed

    Ueda, Mitsuyoshi

    2016-07-01

    Cell surface display of proteins/peptides has been established based on mechanisms of localizing proteins to the cell surface. In contrast to conventional intracellular and extracellular (secretion) expression systems, this method, generally called an arming technology, is particularly effective when using yeasts as a host, because the control of protein folding that is often required for the preparation of proteins can be natural. This technology can be employed for basic and applied research purposes. In this review, I describe various strategies for the construction of engineered yeasts and provide an outline of the diverse applications of this technology to industrial processes such as the production of biofuels and chemicals, as well as bioremediation and health-related processes. Furthermore, this technology is suitable for novel protein engineering and directed evolution through high-throughput screening, because proteins/peptides displayed on the cell surface can be directly analyzed using intact cells without concentration and purification. Functional proteins/peptides with improved or novel functions can be created using this beneficial, powerful, and promising technique. PMID:27305282

  11. IgLON cell adhesion molecules are shed from the cell surface of cortical neurons to promote neuronal growth.

    PubMed

    Sanz, Ricardo; Ferraro, Gino B; Fournier, Alyson E

    2015-02-13

    Matrix metalloproteinases and a disintegrin and metalloproteinases are members of the zinc endopeptidases, which cleave components of the extracellular matrix as well as cell surface proteins resulting in degradation or release of biologically active fragments. Surface ectodomain shedding affects numerous biological processes, including survival, axon outgrowth, axon guidance, and synaptogenesis. In this study, we evaluated the role of metalloproteinases in regulating cortical neurite growth. We found that treatment of mature cortical neurons with pan-metalloproteinase inhibitors or with tissue inhibitors of metalloproteinase-3 reduced neurite outgrowth. Through mass spectrometry, we characterized the metalloproteinase-sensitive cell surface proteome of mature cortical neurons. Members of the IgLON family of glycosylphosphatidylinositol-anchored neural cell adhesion molecules were identified and validated as proteins that were shed from the surface of mature cortical neurons in a metalloproteinase-dependent manner. Introduction of two members of the IgLON family, neurotrimin and NEGR1, in early embryonic neurons was sufficient to confer sensitivity to metalloproteinase inhibitors in neurite outgrowth assays. Outgrowth experiments on immobilized IgLON proteins revealed a role for all IgLON family members in promoting neurite extension from cortical neurons. Together, our findings support a role for metalloproteinase-dependent shedding of IgLON family members in regulating neurite outgrowth from mature cortical neurons.

  12. Spontaneous production of various cytokines except IL-4 from CD4+ T cells in the affected organs of sarcoidosis patients.

    PubMed

    Hoshino, T; Itoh, K; Gouhara, R; Yamada, A; Tanaka, Y; Ichikawa, Y; Azuma, M; Mochizuki, M; Oizumi, K

    1995-11-01

    We investigated surface antigens and spontaneous cytokine production of T cells from bronchoalveolar lavage fluid (BALF) and aqueous humor (AH) from pulmonary sarcoidosis patients for a better understanding of the role of T cells in granuloma formation. The levels of CD3, CD11b, and CD28 antigen expression on freshly isolated T cells in the BALF of patients were significantly lower than those in peripheral blood lymphocytes (PBL) of either sarcoidosis patients or healthy donors (HD). In contrast, the levels of CD80 (B7/B7-1) and CD86 (B70/B7-2) antigen expression were significantly higher on these T cells and alveolar macrophages in the BALF of patients. Fifty-three T cell clones (TCC) established from the BALF and AH of the three sarcoidosis patients displayed primarily either CD4+ CD11b+ CD28+ or CD4+ CD11b- CD28- phenotypes. Most (61-90%) of these TCC spontaneously produced greater amounts of IL-1 alpha, IL-10, tumour necrosis factor (TNF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) than did TCC from the PBL from sarcoidosis patients or HD (P < 0.05). Interferon-gamma (IFN-gamma), IL-6, and IL-2, but not IL-4, were also produced by 40-48% of these TCC. These results suggest that CD4+ T cells of the affected organs of sarcoidosis patients are activated and involved in the immunopathogenesis of sarcoidosis through production of various cytokines.

  13. Nutrient concentrations of runoff as affected by the diameter of unconsolidated material from feedlot surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beef cattle feedlots contain unconsolidated material that accumulates on the feedlot surface during a feeding cycle. This study was conducted to measure the effects of varying diameters of unconsolidated surface material and varying flow rates on nutrient concentrations in runoff. Unconsolidated sur...

  14. Factors affecting projected Arctic surface shortwave heating and albedo change in coupled climate models

    PubMed Central

    Holland, Marika M.; Landrum, Laura

    2015-01-01

    We use a large ensemble of simulations from the Community Earth System Model to quantify simulated changes in the twentieth and twenty-first century Arctic surface shortwave heating associated with changing incoming solar radiation and changing ice conditions. For increases in shortwave absorption associated with albedo reductions, the relative influence of changing sea ice surface properties and changing sea ice areal coverage is assessed. Changes in the surface sea ice properties are associated with an earlier melt season onset, a longer snow-free season and enhanced surface ponding. Because many of these changes occur during peak solar insolation, they have a considerable influence on Arctic surface shortwave heating that is comparable to the influence of ice area loss in the early twenty-first century. As ice area loss continues through the twenty-first century, it overwhelms the influence of changes in the sea ice surface state, and is responsible for a majority of the net shortwave increases by the mid-twenty-first century. A comparison with the Arctic surface albedo and shortwave heating in CMIP5 models indicates a large spread in projected twenty-first century change. This is in part related to different ice loss rates among the models and different representations of the late twentieth century ice albedo and associated sea ice surface state. PMID:26032318

  15. Nanoscale Roughness and Morphology Affect the IsoElectric Point of Titania Surfaces

    PubMed Central

    Borghi, Francesca; Vyas, Varun; Podestà, Alessandro; Milani, Paolo

    2013-01-01

    We report on the systematic investigation of the role of surface nanoscale roughness and morphology on the charging behaviour of nanostructured titania (TiO2) surfaces in aqueous solutions. IsoElectric Points (IEPs) of surfaces have been characterized by direct measurement of the electrostatic double layer interactions between titania surfaces and the micrometer-sized spherical silica probe of an atomic force microscope in NaCl aqueous electrolyte. The use of a colloidal probe provides well-defined interaction geometry and allows effectively probing the overall effect of nanoscale morphology. By using supersonic cluster beam deposition to fabricate nanostructured titania films, we achieved a quantitative control over the surface morphological parameters. We performed a systematical exploration of the electrical double layer properties in different interaction regimes characterized by different ratios of characteristic nanometric lengths of the system: the surface rms roughness Rq, the correlation length ξ and the Debye length λD. We observed a remarkable reduction by several pH units of IEP on rough nanostructured surfaces, with respect to flat crystalline rutile TiO2. In order to explain the observed behavior of IEP, we consider the roughness-induced self-overlap of the electrical double layers as a potential source of deviation from the trend expected for flat surfaces. PMID:23874708

  16. Anomalous cell surface structure of sickle cell anemia erythrocytes as demonstrated by cell surface labeling and endo-beta-galactosidase treatment

    SciTech Connect

    Fukuda, M.; Fukuda, M.N.; Hakomori, S.; Papayannopoulou, T.

    1981-01-01

    Erythrocyte surface glycoproteins from patients with various types of sickle cell anemia have been analyzed and compared with those from normal individuals. By hemagglutination with various anti-carbohydrate antibodies, sickle cells showed profound increase of i antigens and moderate increase of GlcNAc beta 1 leads to 3Gal beta 1 leads to 3 Glc structure, whereas antigenicity toward globosidic structure was unchanged. In parallel to these findings, erythrocytes of sickle cell patients have additional sialylated lactosaminoglycan in Band 3. Thus, it can be concluded that erythrocytes of sickle cell patients are characterized by an altered cell surface structure which does not appear to be due to topographical changes of cell surface membrane. It is possible that the anemia or the ''stress'' hematopoiesis in these patients is responsible for these changes.

  17. Loss of cell wall alpha(1–3) glucan affects Cryptococcus neoformans from ultrastructure to virulence

    PubMed Central

    Reese, Amy J.; Yoneda, Aki; Breger, Julia A.; Beauvais, Anne; Liu, Hong; Griffith, Cara L.; Bose, Indrani; Kim, Myoung-Ju; Skau, Colleen; Yang, Sarah; Sefko, Julianne A.; Osumi, Masako; Latge, Jean-Paul; Mylonakis, Eleftherios; Doering, Tamara L.

    2007-01-01

    SUMMARY Yeast cell walls are critical for maintaining cell integrity, particularly in the face of challenges such as growth in mammalian hosts. The pathogenic fungus Cryptococcus neoformans additionally anchors its polysaccharide capsule to the cell surface via α(1–3) glucan in the wall. Cryptococcal cells disrupted in their alpha glucan synthase gene were sensitive to stresses, including temperature, and showed difficulty dividing. These cells lacked surface capsule, although they continued to shed capsule material into the environment. Electron microscopy showed that the alpha glucan that is usually localized to the outer portion of the cell wall was absent, the outer region of the wall was highly disorganized, and the inner region was hypertrophic. Analysis of cell wall composition demonstrated complete loss of alpha glucan accompanied by a compensatory increase in chitin/chitosan and a redistribution of beta glucan between cell wall fractions. The mutants were unable to grow in a mouse model of infection, but caused death in nematodes. These studies integrate morphological and biochemical investigations of the role of alpha glucan in the cryptococcal cell wall. PMID:17244196

  18. Fibronectin and asialoglyprotein receptor mediate hepatitis B surface antigen binding to the cell surface.

    PubMed

    Yang, Jing; Wang, Feng; Tian, Linlin; Su, Jing; Zhu, Xiangqian; Lin, Li; Ding, Xiaoran; Wang, Xuejun; Wang, Shengqi

    2010-06-01

    Both fibronectin and the asialoglycoprotein receptor (ASGPR) have been identified by some investigators as partners for hepatitis B virus (HBV) envelope proteins. Because fibronectin is a natural ligand for ASGPR, we speculated that HBV might attach to ASGPR expressed on the hepatocyte surface via fibronectin. To test this hypothesis, we first confirmed by co-immunoprecipitation that ASGPR, fibronectin and HBsAg bind to each other in HepG2.2.15 cells, and possible binding domains were identified by GST pull-down. In addition, by measuring binding of HBsAg to cells, we found that ASGPR and fibronectin enhanced the binding capability of HBsAg to HepG2 cells, and even to 293T and CHO cells, which normally do not bind HBV. In conclusion, our findings suggest that both fibronectin and ASGPR mediate HBsAg binding to the cell surface, which provides further evidence for the potential roles of these two proteins in mediating HBV binding to liver cells. PMID:20364278

  19. Triclosan and bisphenol a affect decidualization of human endometrial stromal cells.

    PubMed

    Forte, Maurizio; Mita, Luigi; Cobellis, Luigi; Merafina, Verdiana; Specchio, Raffaella; Rossi, Sergio; Mita, Damiano Gustavo; Mosca, Lavinia; Castaldi, Maria Antonietta; De Falco, Maria; Laforgia, Vincenza; Crispi, Stefania

    2016-02-15

    In recent years, impaired fertility and endometrium related diseases are increased. Many evidences suggest that environmental pollution might be considered a risk factor for endometrial physiopathology. Among environmental pollutants, endocrine disrupting chemicals (EDCs) act on endocrine system, causing hormonal imbalance which, in turn, leads to female and male reproductive dysfunctions. In this work, we studied the effects of triclosan (TCL) and bisphenol A (BPA), two widespread EDCs, on human endometrial stromal cells (ESCs), derived from endometrial biopsies from woman not affected by endometriosis. Cell proliferation, cell cycle, migration and decidualization mechanisms were investigated. Treatments have been performed with both the EDCs separately or in presence and in absence of progesterone used as decidualization stimulus. Both TCL and BPA did not affect cell proliferation, but they arrested ESCs at G2/M phase of cell cycle enhancing cell migration. TCL and BPA also increased gene expression and protein levels of some decidualization markers, such as insulin growth factor binding protein 1 (IGFBP1) and prolactin (PRL), amplifying the effect of progesterone alone. All together, our data strongly suggest that TCL and BPA might alter human endometrium physiology so affecting fertility and pregnancy outcome. PMID:26604029

  20. Brown spider venom toxins interact with cell surface and are endocytosed by rabbit endothelial cells.

    PubMed

    Nowatzki, Jenifer; de Sene, Reginaldo Vieira; Paludo, Katia Sabrina; Veiga, Silvio Sanches; Oliver, Constance; Jamur, Maria Célia; Nader, Helena Bonciani; Trindade, Edvaldo S; Franco, Célia Regina C

    2010-09-15

    Bites from the Loxosceles genus (brown spiders) cause severe clinical symptoms, including dermonecrotic injury, hemorrhage, hemolysis, platelet aggregation and renal failure. Histological findings of dermonecrotic lesions in animals exposed to Loxosceles intermedia venom show numerous vascular alterations. Study of the hemorrhagic consequences of the venom in endothelial cells has demonstrated that the degeneration of blood vessels results not only from degradation of the extracellular matrix molecule or massive leukocyte infiltration, but also from a direct and primary activity of the venom on endothelial cells. Exposure of an endothelial cell line in vitro to L. intermedia venom induce morphological alterations, such as cell retraction and disadhesion to the extracellular matrix. The aim of the present study was to investigate the interaction between the venom toxins and the endothelial cell surface and their possible internalization, in order to illuminate the information about the deleterious effect triggered by venom. After treating endothelial cells with venom toxins, we observed that the venom interacts with cell surface. Venom treatment also can cause a reduction of cell surface glycoconjugates. When cells were permeabilized, it was possible to verify that some venom toxins were internalized by the endothelial cells. The venom internalization involves endocytic vesicles and the venom was detected in the lysosomes. However, no damage to lysosomal integrity was observed, suggesting that the cytotoxic effect evoked by L. intermedia venom on endothelial cells is not mediated by venom internalization.

  1. Stable isotope labeling of oligosaccharide cell surface antigens

    SciTech Connect

    Unkefer, C.J.; Silks, L.A. III; Martinez, R.A.

    1998-12-31

    The overall goal of this Laboratory Directed Research and Development (LDRD) project was to develop new methods for synthesis of {sup 13}C-labeled oligosaccharides that are required for nuclear magnetic resonance (NMR) studies of their solution conformation. Oligosaccharides are components of the cell`s outer surface and are involved in important processes such as cell-cell recognition and adhesion. Recently, Danishefsky and coworkers at Slone-Kettering Cancer Center developed a method for the solid-phase chemical synthesis of oligosaccharides. The specific goal of this LDRD project was to prepare uniform {sup 13}C-labeled aldohexose precursors required for the solid-phase synthesis of the Lewis blood-group antigenic determinants. We report the synthesis of {sup 13}C-labeled D-glucal, D-galactal and Fucosyl precursors. We have been collaborating with the Danishefsky group on the synthesis of the Lewis oligosaccharides and the NMR analysis of their solution conformation.

  2. Integrated Metabolomics, Transcriptomics and Proteomics Identifies Metabolic Pathways Affected by Anaplasma phagocytophilum Infection in Tick Cells.

    PubMed

    Villar, Margarita; Ayllón, Nieves; Alberdi, Pilar; Moreno, Andrés; Moreno, María; Tobes, Raquel; Mateos-Hernández, Lourdes; Weisheit, Sabine; Bell-Sakyi, Lesley; de la Fuente, José

    2015-12-01

    Anaplasma phagocytophilum is an emerging zoonotic pathogen that causes human granulocytic anaplasmosis. These intracellular bacteria establish infection by affecting cell function in both the vertebrate host and the tick vector, Ixodes scapularis. Previous studies have characterized the tick transcriptome and proteome in response to A. phagocytophilum infection. However, in the postgenomic era, the integration of omics datasets through a systems biology approach allows network-based analyses to describe the complexity and functionality of biological systems such as host-pathogen interactions and the discovery of new targets for prevention and control of infectious diseases. This study reports the first systems biology integration of metabolomics, transcriptomics, and proteomics data to characterize essential metabolic pathways involved in the tick response to A. phagocytophilum infection. The ISE6 tick cells used in this study constitute a model for hemocytes involved in pathogen infection and immune response. The results showed that infection affected protein processing in endoplasmic reticulum and glucose metabolic pathways in tick cells. These results supported tick-Anaplasma co-evolution by providing new evidence of how tick cells limit pathogen infection, while the pathogen benefits from the tick cell response to establish infection. Additionally, ticks benefit from A. phagocytophilum infection by increasing survival while pathogens guarantee transmission. The results suggested that A. phagocytophilum induces protein misfolding to limit the tick cell response and facilitate infection but requires protein degradation to prevent ER stress and cell apoptosis to survive in infected cells. Additionally, A. phagocytophilum may benefit from the tick cell's ability to limit bacterial infection through PEPCK inhibition leading to decreased glucose metabolism, which also results in the inhibition of cell apoptosis that increases infection of tick cells. These results

  3. The sertolian epithelium in the testis of men affected by 'Sertoli-cell-only syndrome'.

    PubMed

    Tedde, G; Montella, A; Fiocca, D; Delrio, A N

    1993-01-01

    Because of the architectural complexity of the seminiferous epithelium, the Sertoli cell is extremely difficult to study. The individual cellular constituents of the tubular wall are intimately associated with one another; especially Sertoli cells and germinal cells are tightly connected. As implied by the name, Sertoli-cell-only syndrome (SCOS) is characterized by the presence of only Sertoli cells in the seminiferous tubule. The absence of germinal cells makes this condition ideal for the morphological study of Sertoli cell. Testicular biopsy specimens of subjects affected by SCOS were studied under light and electron microscopy. The Sertoli cells appeared to be morphologically normal, except for their shape, that appears to be columnar as result of the complete absence of the germinal cells. The cellular outlines were irregular, particularly at the base, but the cytoplasm contained normal organelles and inclusions. The presence of both pale and dark elements was evident. These differences in staining reflect the variability in concentration of glycogen particles and intermediate microfilaments in the cytoplasm. In spite of these differences between Sertoli cells in SCOS and those in normal subjects, SCOS represents a satisfactory model for the morphological and functional analysis of the Sertoli cells. PMID:7694556

  4. Physico-chemical properties of PDMS surfaces suitable as substrates for cell cultures

    NASA Astrophysics Data System (ADS)

    Raczkowska, Joanna; Prauzner-Bechcicki, Szymon; Lukes, Jaroslav; Sepitka, Josef; Bernasik, Andrzej; Awsiuk, Kamil; Paluszkiewicz, Czesława; Pabijan, Joanna; Lekka, Małgorzata; Budkowski, Andrzej

    2016-12-01

    Elastic properties of the substrate have profound effect on adhesion and proliferation of cells. Here, we introduce a method to produce polydimethylsiloxane (PDMS) substrates with stiffness tuned monotonically from 1.67 to 0.24 MPa, by the time of UV irradiation adjusted up to 5 h. The Young's modulus (determined by using nanoindenter) scales linearly with stiffness calculated using AFM-based force spectroscopy data. Such a relation enables the determination of the Young modulus from AFM force - distance curves also when the Herz model is not applicable. Our findings demonstrate that surface properties of PDMS substrates are not affected by the applied methodology of tuning substrate elasticity. Finally, the colorimetric proliferation assay (MTT) carried out for non-malignant (HCV29) and cancerous (T24) bladder cancer cells depicted a significant contribution of PDMS substrate elasticity to the behavior of cells. The softer PDMS substrate demonstrated excellent cytocompatibility whereas the stiff one is more cell-repellent.

  5. Pharmacological induction of cell surface GRP78 contributes to apoptosis in triple negative breast cancer cells.

    PubMed

    Raiter, Annat; Yerushalmi, Rinat; Hardy, Britta

    2014-11-30

    Breast cancer tumor with triple-negative receptors (estrogen, progesterone and Her 2, receptors) is the most aggressive and deadly subtype, with high rates of disease recurrence and poor survival. Here, we show that induction in cell surface GRP78 by doxorubicin and tunicamycin was associated with CHOP/GADD153 upregulation and increase in apoptosis in triple negative breast cancer tumor cells. GRP78 is a major regulator of the stress induced unfolded protein response pathway and CHOP/GADD153 is a pro-apoptotic transcription factor associated exclusively with stress induced apoptosis. The blocking of cell surface GRP78 by anti-GRP78 antibody prevented apoptosis, suggesting that induction of cell surface GRP78 by doxorubicin and tunicamycin is required for apoptosis. A better understanding of stress induction of apoptotic signaling in triple negative breast cancer cells may help to define new therapeutic strategies.

  6. The cell surface expressed nucleolin is a glycoprotein that triggers calcium entry into mammalian cells

    SciTech Connect

    Losfeld, Marie-Estelle; Khoury, Diala El; Mariot, Pascal; Carpentier, Mathieu; Krust, Bernard; Briand, Jean-Paul; Mazurier, Joel; Hovanessian, Ara G.; Legrand, Dominique

    2009-01-15

    Nucleolin is an ubiquitous nucleolar phosphoprotein involved in fundamental aspects of transcription regulation, cell proliferation and growth. It has also been described as a shuttling molecule between nucleus, cytosol and the cell surface. Several studies have demonstrated that surface nucleolin serves as a receptor for various extracellular ligands implicated in cell proliferation, differentiation, adhesion, mitogenesis and angiogenesis. Previously, we reported that nucleolin in the extranuclear cell compartment is a glycoprotein containing N- and O-glycans. In the present study, we show that glycosylation is an essential requirement for surface nucleolin expression, since it is prevented when cells are cultured in the presence of tunicamycin, an inhibitor of N-glycosylation. Accordingly, surface but not nuclear nucleolin is radioactively labeled upon metabolic labeling of cells with [{sup 3}H]glucosamine. Besides its well-demonstrated role in the internalization of specific ligands, here we show that ligand binding to surface nucleolin could also induce Ca{sup 2+} entry into cells. Indeed, by flow cytometry, microscopy and patch-clamp experiments, we show that the HB-19 pseudopeptide, which binds specifically surface nucleolin, triggers rapid and intense membrane Ca{sup 2+} fluxes in various types of cells. The use of several drugs then indicated that Store-Operated Ca{sup 2+} Entry (SOCE)-like channels are involved in the generation of these fluxes. Taken together, our findings suggest that binding of an extracellular ligand to surface nucleolin could be involved in the activation of signaling pathways by promoting Ca{sup 2+} entry into cells.

  7. Characterization of atrial natriuretic peptide degradation by cell-surface peptidase activity on endothelial cells

    NASA Technical Reports Server (NTRS)

    Frost, S. J.; Whitson, P. A.

    1993-01-01

    Atrial natriuretic peptide (ANP) is a fluid-regulating peptide hormone that promotes vasorelaxation, natriuresis, and diuresis. The mechanisms for the release of ANP and for its clearance from the circulation play important roles in modulating its biological effects. Recently, we have reported that the cell surface of an endothelial cell line, CPA47, could degrade 125I-ANP in the presence of EDTA. In this study, we have characterized this degradation of 125I-ANP. The kinetics of ANP degradation by the surface of CPA47 cells were first order, with a Km of 320 +/- 60 nM and Vmax of 35 +/- 14 pmol of ANP degraded/10 min/10(5) cells at pH 7.4. ANP is degraded by the surface of CPA47 cells over a broad pH range from 7.0-8.5. Potato carboxypeptidase inhibitor and bestatin inhibited 125I-ANP degradation, suggesting that this degradative activity on the surface of CPA47 cells has exopeptidase characteristics. The selectivity of CPA47 cell-surface degradation of ANP was demonstrated when 125I-ANP degradation was inhibited in the presence of neuropeptide Y and angiotensin I and II but not bradykinin, bombesin, endothelin-1, or substance P. The C-terminal amino acids phe26 and tyr28 were deduced to be important for ANP interaction with the cell-surface peptidase(s) based on comparison of the IC50 of various ANP analogues and other natriuretic peptides for the inhibition of ANP degradation. These data suggest that a newly characterized divalent cation-independent exopeptidase(s) that selectively recognizes ANP and some other vasoactive peptides exists on the surface of endothelial cells.

  8. The relationship of surface roughness and cell response of chemical surface modification of titanium

    PubMed Central

    Zareidoost, Amir; Ghaseme, Behrooz

    2012-01-01

    Implant surface topography influences osteoblastic proliferation, differentiation and extracellular matrix protein expressions. Previous researches proved that chemical surface modification of titanium implants could be used to improve Bone-to-implant contact. In this study, the surface topography, chemistry and biocompatibility of polished titanium surfaces treated with mixed solution of three acids containing HCl, HF and H3PO4 with different etched conditions for example concentration, time and addition of calcium chloride were studied. Osteoblast cells (MG-63) were cultured on different groups of titanium surfaces. In order to investigate titanium surfaces, SEM, AFM and EDS analyses were carried out. The results showed that surfaces treated with HCl–HF–H3PO4 had higher roughness, lower cytotoxicity level and better biocompatibility than controls. Moreover, addition of calcium chloride into mixed solution of three acids containing HCl, HF and H3PO4 is an important, predominant and new technique for obtaining biofunction in metals for biomedical use including dentistry. PMID:22460230

  9. The interaction between the tennis court and the player: how does surface affect leg stiffness?

    PubMed

    Maquirriain, Javier

    2013-03-01

    An adequate level of leg stiffness is necessary for an optimal tennis performance and leg stiffness should be adapted to frequently changing surfaces as tennis players usually play on different courts. The aim of this study was to evaluate leg stiffness in competitive tennis players on different court surfaces. Ten healthy competitive tennis players (nine men and one woman; mean age = 17.6 +/- 3.2 years) underwent leg stiffness testing by modeling the vertical ground reaction force using an optical system. Flight time and contact time were determined during hopping on two different tennis court surfaces (clay and acrylic). No significant difference was found in the flight time, contact time, and jump height between the surfaces. No significant difference in leg stiffness was found between the surfaces (18.25 +/- 5.8 and 19.27 +/- 4.9 kN/m for clay and acrylic, respectively; p = 0.28). This study demonstrated that contact time and flight time as well as leg stiffness of tennis players remained unchanged when hopping on two different tennis surfaces. Results of this research provide objective data regarding the tennis-specific loading of the locomotor system and proper mechanical adaptation of the player on different surfaces, which may be useful for testing protocols and planning training programs.

  10. Probing and mapping electrode surfaces in solid oxide fuel cells.

    PubMed

    Blinn, Kevin S; Li, Xiaxi; Liu, Mingfei; Bottomley, Lawrence A; Liu, Meilin

    2012-09-20

    Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen (1-7). The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion(2). Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation(8-12). It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition(8, 10, 13, 14) ("coking") and sulfur poisoning(11, 15) and the manner in which surface modifications stave off this degradation(16). The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM

  11. Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

    PubMed Central

    Blinn, Kevin S.; Li, Xiaxi; Liu, Mingfei; Bottomley, Lawrence A.; Liu, Meilin

    2012-01-01

    Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM

  12. Bacterial Cell Surface Adsorption of Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    Jiao, Y.; Park, D.; Reed, D.; Fujita, Y.; Yung, M.; Anderko, A.; Eslamimanesh, A.

    2015-12-01

    Rare earth elements (REE) play a critical role in many emerging clean energy technologies, including high-power magnets, wind turbines, solar panels, hybrid/electric vehicle batteries and lamp phosphors. In order to sustain demand for such technologies given current domestic REE shortages, there is a need to develop new approaches for ore processing/refining and recycling of REE-containing materials. To this end, we have developed a microbially-mediated bioadsorption strategy with application towards enrichment of REE from complex mixtures. Specifically, the bacterium Caulobacter crescentus was genetically engineered to display lanthanide binding tags (LBTs), short peptides that possess high affinity and specificity for rare earth elements, on its cell surface S-layer protein. Under optimal conditions, LBT-displayed cells adsorbed greater than 5-fold more REE than control cells lacking LBTs. Competition binding experiments with a selection of REEs demonstrated that our engineered cells could facilitate separation of light- from heavy- REE. Importantly, binding of REE onto our engineered strains was much more favorable compared to non-REE metals. Finally, REE bound to the cell surface could be stripped off using citrate, providing an effective and non-toxic REE recovery method. Together, this data highlights the potential of our approach for selective REE enrichment from REE containing mixtures.

  13. Cdon, a cell surface protein, mediates oligodendrocyte differentiation and myelination.

    PubMed

    Wang, Li-Chun; Almazan, Guillermina

    2016-06-01

    During central nervous system development, oligodendrocyte progenitors (OLPs) establish multiple branched processes and axonal contacts to initiate myelination. A complete understanding of the molecular signals implicated in cell surface interaction to initiate myelination/remyelination is currently lacking. The objective of our study was to assess whether Cdon, a cell surface protein that was shown to participate in muscle and neuron cell development, is involved in oligodendrocyte (OLG) differentiation and myelination. Here, we demonstrate that endogenous Cdon protein is expressed in OLPs, increasing in the early differentiation stages and decreasing in mature OLGs. Immunocytochemistry of endogenous Cdon showed localization on both OLG cell membranes and cellular processes exhibiting puncta- or varicosity-like structures. Cdon knockdown with siRNA decreased protein levels by 62% as well as two myelin-specific proteins, MBP and MAG. Conversely, overexpression of full-length rat Cdon increased myelin proteins in OLGs. The complexity of OLGs branching and contact point numbers with axons were also increased in Cdon overexpressing cells growing alone or in coculture with dorsal root ganglion neurons (DRGNs). Furthermore, myelination of DRGNs was decreased when OLPs were transfected with Cdon siRNA. Altogether, our results suggest that Cdon participates in OLG differentiation and myelination, most likely in the initial stages of development.

  14. Interfacing biomembrane mimetic polymer surfaces with living cells Surface modification for reliable bioartificial liver

    NASA Astrophysics Data System (ADS)

    Iwasaki, Yasuhiko; Takami, Utae; Sawada, Shin-ichi; Akiyoshi, Kazunari

    2008-11-01

    The surface design used for reducing nonspecific biofouling is one of the most important issues for the fabrication of medical devices. We present here a newly synthesized a carbohydrate-immobilized phosphorylcholine polymer for surface modification of medical devices to control the interface with living cells. A random copolymer composed of 2-methacryloyloxyethyl phosphorylcholine (MPC), n-butyl methacrylate (BMA), and 2-lactobionamidoethyl methacrylate (LAMA) was synthesized by conventional radical polymerization. The monomer feeding ratio in the copolymer was adjusted to 24/75/1 (MPC/BMA/LAMA). The copolymer (PMBL1.0) could be coated by solvent evaporation from an ethanol solution. Cells of the human hepatocellular liver carcinoma cell line (HepG2) having asialoglycoprotein receptors (ASGPRs) were seeded on PMBL1.0 or poly(BMA) (PBMA)-coated PET plates. On PBMA, many adherent cells were observed and were well spread with monolayer adhesion. HepG2 adhesion was observed on PMBL1.0 because the cell has ASGPRs. Furthermore, some of the cells adhering to PMBL1.0 had a spheroid formation and similarly shaped spheroids were scattered on the surface. According to confocal laser microscopic observation after 96 h cultivation, it was found that albumin production preferentially occurred in the center of the spheroid. The albumin production of the cells that adhered to PBMA was sparse. The amount of albumin production per unit cell that adhered to PMBL1.0 was determined by ELISA and was significantly higher than that which adhered to PBMA. Long-term cultivation of HepG2 was also performed using hollow fiber mini-modules coated with PMBL1.0. The concentration of albumin produced from HepG2 increased continuously for one month. In the mini-module, the function of HepG2 was effectively preserved for that period. On the hollow fiber membrane, spheroid formation of HepG2 cells was also observed. In conclusion, PMBL1.0 can provide a suitable surface for the cultivation of

  15. The mechanics of cell crawling over a flat surface

    NASA Astrophysics Data System (ADS)

    Alonso-Latorre, Baldomero; Rodriguez-Rodriguez, Javier; Aliseda, Alberto; Meili, Rudolf; Firtel, Richard; Lasheras, Juan

    2006-03-01

    The chemotaxis of different strains of the amoeba Dictyostelium Dicoideum when exposed to a wide range of concentrations and gradients of chemoattractant has been studied experimentally. First, the time evolution of the velocity as well as the shape of the cell have been measured from microscopy images for a large number of individuals. Secondly, the force that the amoebas exert over the substrate in order to propel themselves has also been measured. Some insights into the physical mechanism by which cells crawl over the surface are obtained by comparing the time evolution of those magnitudes for the different strains under study.

  16. Spontaneous bilateral kidney rupture during autologous stem cell transplantation in a patient affected by amyloidosis

    PubMed Central

    Ferrannini, Michele; Vischini, Gisella; De Angelis, Gottardo; Giannakakis, Konstantinos; Arcese, William

    2011-01-01

    Kidney spontaneous rupture is not a recognized complication neither for amyloidosis nor of autologous stem cell transplantation (ASCT). A 46-year-old white woman, affected by nephrotic syndrome, was diagnosed as AL amyloidosis by renal biopsy. We report the singular case of a bilateral spontaneous kidney rupture during ASCT for AL with renal rescue. PMID:25984105

  17. Key Immune Cell Cytokines Affects the Telomere Activity of Cord Blood Cells In vitro

    PubMed Central

    Brazvan, Balal; Farahzadi, Raheleh; Mohammadi, Seyede Momeneh; Montazer Saheb, Soheila; Shanehbandi, Dariush; Schmied, Laurent; Soleimani Rad, Jafar; Darabi, Masoud; Nozad Charoudeh, Hojjatollah

    2016-01-01

    Purpose: Telomere is a nucleoprotein complex at the end of eukaryotic chromosomes and its length is regulated by telomerase. The number of DNA repeat sequence (TTAGGG)n is reduced with each cell division in differentiated cells. The aim of this study was to evaluate the effect of SCF (Stem Cell Factor), Flt3 (Fms- Like tyrosine kinase-3), Interleukin-2, 7 and 15 on telomere length and hTERT gene expression in mononuclear and umbilical cord blood stem cells (CD34+ cells) during development to lymphoid cells. Methods: The mononuclear cells were isolated from umbilical cord blood by Ficoll-Paque density gradient. Then cells were cultured for 21 days in the presence of different cytokines. Telomere length and hTERT gene expression were evaluated in freshly isolated cells, 7, 14 and 21 days of culture by real-time PCR. The same condition had been done for CD34+ cells but telomere length and hTERT gene expression were measured at initial and day 21 of the experiment. Results: Highest hTERT gene expression and maximum telomere length were measured at day14 of MNCs in the presence of IL-7 and IL-15. Also, there was a significant correlation between telomere length and telomerase gene expression in MNCs at 14 days in a combination of IL-7 and IL-15 (r = 0.998, p =0.04). In contrast, IL-2 showed no distinct effect on telomere length and hTERT gene expression in cells. Conclusion: Taken together, IL-7 and IL-15 increased telomere length and hTERT gene expression at 14 day of the experiment. In conclusion, it seems likely that cells maintain naïve phenotype due to prolonged exposure of IL-7 and IL-15. PMID:27478776

  18. Dendritic Cells under Hypoxia: How Oxygen Shortage Affects the Linkage between Innate and Adaptive Immunity.

    PubMed

    Winning, Sandra; Fandrey, Joachim

    2016-01-01

    Dendritic cells (DCs) are considered as one of the main regulators of immune responses. They collect antigens, process them, and present typical antigenic structures to lymphocytes, thereby inducing an adaptive immune response. All these processes take place under conditions of oxygen shortage (hypoxia) which is often not considered in experimental settings. This review highlights how deeply hypoxia modulates human as well as mouse immature and mature dendritic cell functions. It tries to link in vitro results to actual in vivo studies and outlines how hypoxia-mediated shaping of dendritic cells affects the activation of (innate) immunity.

  19. Dendritic Cells under Hypoxia: How Oxygen Shortage Affects the Linkage between Innate and Adaptive Immunity

    PubMed Central

    Winning, Sandra; Fandrey, Joachim

    2016-01-01

    Dendritic cells (DCs) are considered as one of the main regulators of immune responses. They collect antigens, process them, and present typical antigenic structures to lymphocytes, thereby inducing an adaptive immune response. All these processes take place under conditions of oxygen shortage (hypoxia) which is often not considered in experimental settings. This review highlights how deeply hypoxia modulates human as well as mouse immature and mature dendritic cell functions. It tries to link in vitro results to actual in vivo studies and outlines how hypoxia-mediated shaping of dendritic cells affects the activation of (innate) immunity. PMID:26966693

  20. Would cancer stem cells affect the future investment in stem cell therapy.

    PubMed

    Rameshwar, Pranela

    2012-04-20

    The common goal within the overwhelming interests in stem cell research is to safely translate the science to patients. Although there are various methods by which this goal can be reached, this editorial emphasizes the safety of mesenchymal stem cell (MSC) transplant and possible confounds by the growing information on cancer stem cells (CSCs). There are several ongoing clinical trials with MSCs and their interactions with CSCs need to be examined. The rapid knowledge on MSCs and CSCs has now collided with regards to the safe treatment of MSCs. The information discussed on MSCs can be extrapolated to other stem cells with similar phenotype and functions such as placenta stem cells. MSCs are attractive for cell therapy, mainly due to reduced ethical concerns, ease in expansion and reduced ability to be transformed. Also, MSCs can exert both immune suppressor and tissue regeneration simultaneously. It is expected that any clinical trial with MSCs will take precaution to ensure that the cells are not transformed. However, going forward, the different centers should be aware that MSCs might undergo oncogenic events, especially as undifferentiated cells or early differentiated cells. Another major concern for MSC therapy is their ability to promote tumor growth and perhaps, to protect CSCs by altered immune responses. These issues are discussed in light of a large number of undiagnosed cancers.

  1. Observed near-surface atmospheric moisture content changes affected by irrigation development in Xinjiang, Northwest China

    NASA Astrophysics Data System (ADS)

    Han, Songjun; Tang, Qiuhong; Xu, Di; Wang, Shaoli; Yang, Zhiyong

    2016-08-01

    The effects of irrigation development on observed near-surface atmospheric moisture changes remain unclear in arid Xinjiang. In this study, cultivated land fractions (CFs) within a 4-km radius of 90 meteorological stations over Xinjiang, which are inferred from the 2000 land use map, are used as a quantitative indicator of irrigation intensity. Trends of observed water vapor pressure and relative humidity during the growing season (May to September) from 1959 to 2006 are significantly positively correlated with CFs of the meteorological stations. Stations with larger CFs experience a more rapid increase in near-surface atmospheric moisture than stations with small CFs. Results indicate that growing season near-surface atmospheric moisture wetting is enhanced by irrigation development for stations with high levels of cultivated land uses. The land use around stations should be considered when analyzing the observed near-surface atmospheric moisture changes in Xinjiang.

  2. Sialyl-lactotetra, a novel cell surface marker of undifferentiated human pluripotent stem cells.

    PubMed

    Barone, Angela; Säljö, Karin; Benktander, John; Blomqvist, Maria; Månsson, Jan-Eric; Johansson, Bengt R; Mölne, Johan; Aspegren, Anders; Björquist, Petter; Breimer, Michael E; Teneberg, Susann

    2014-07-01

    Cell surface glycoconjugates are used as markers for undifferentiated pluripotent stem cells. Here, antibody binding and mass spectrometry characterization of acid glycosphingolipids isolated from a large number (1 × 10(9) cells) of human embryonic stem cell (hESC) lines allowed identification of several novel acid glycosphingolipids, like the gangliosides sialyl-lactotetraosylceramide and sialyl-globotetraosylceramide, and the sulfated glycosphingolipids sulfatide, sulf-lactosylceramide, and sulf-globopentaosylceramide. A high cell surface expression of sialyl-lactotetra on hESC and human induced pluripotent stem cells (hiPSC) was demonstrated by flow cytometry, immunohistochemistry, and electron microscopy, whereas sulfated glycosphingolipids were only found in intracellular compartments. Immunohistochemistry showed distinct cell surface anti-sialyl-lactotetra staining on all seven hESC lines and three hiPSC lines analyzed, whereas no staining of hESC-derived hepatocyte-like or cardiomyocyte-like cells was obtained. Upon differentiation of hiPSC into hepatocyte-like cells, the sialyl-lactotetra epitope was rapidly down-regulated and not detectable after 14 days. These findings identify sialyl-lactotetra as a promising marker of undifferentiated human pluripotent stem cells.

  3. Sialyl-lactotetra, a Novel Cell Surface Marker of Undifferentiated Human Pluripotent Stem Cells*

    PubMed Central

    Barone, Angela; Säljö, Karin; Benktander, John; Blomqvist, Maria; Månsson, Jan-Eric; Johansson, Bengt R.; Mölne, Johan; Aspegren, Anders; Björquist, Petter; Breimer, Michael E.; Teneberg, Susann

    2014-01-01

    Cell surface glycoconjugates are used as markers for undifferentiated pluripotent stem cells. Here, antibody binding and mass spectrometry characterization of acid glycosphingolipids isolated from a large number (1 × 109 cells) of human embryonic stem cell (hESC) lines allowed identification of several novel acid glycosphingolipids, like the gangliosides sialyl-lactotetraosylceramide and sialyl-globotetraosylceramide, and the sulfated glycosphingolipids sulfatide, sulf-lactosylceramide, and sulf-globopentaosylceramide. A high cell surface expression of sialyl-lactotetra on hESC and human induced pluripotent stem cells (hiPSC) was demonstrated by flow cytometry, immunohistochemistry, and electron microscopy, whereas sulfated glycosphingolipids were only found in intracellular compartments. Immunohistochemistry showed distinct cell surface anti-sialyl-lactotetra staining on all seven hESC lines and three hiPSC lines analyzed, whereas no staining of hESC-derived hepatocyte-like or cardiomyocyte-like cells was obtained. Upon differentiation of hiPSC into hepatocyte-like cells, the sialyl-lactotetra epitope was rapidly down-regulated and not detectable after 14 days. These findings identify sialyl-lactotetra as a promising marker of undifferentiated human pluripotent stem cells. PMID:24841197

  4. Surface enhanced Raman spectroscopy in breast cancer cells

    PubMed Central

    González-Solís, JL; Luévano-Colmenero, GH; Vargas-Mancilla, J

    2013-01-01

    Background and aims: Raman spectroscopy is a vibrational technique which provides information about the chemical structure. Nevertheless, since many chemicals are present in a cell at very low concentration, the Raman signal observed from a single cell is extremely weak. In surface enhanced Raman scattering (SERS), Raman signals can be enhanced by many orders of magnitude when nanoparticles are incorporated into the cell. Materials (subjects) and methods: The tumor biopsies were obtained from 5 patients who were clinically diagnosed with breast cancer. Breast cancer cells isolated from the biopsy were washed, centrifuged and seeded out. Cultivation took place in DMEM at 37°C in a humidified of 5% CO2 in air with addition of colloidal silver nanoparticles of 40 nm into the cell by sonication. Immediately, the washed cells were analyzed in phosphate buffered saline (PBS) at pH 7. Raman analysis was carried out on the Jobin-Yvon LabRAM HR800 microscope system, with a NIR 830 nm laser excitation source. Results: The strongly enhanced Raman signals allow Raman measurements of a single cell in the 200–1800 cm−1 range in relatively short collection times (5 second) using 17 mW near-infrared excitation. Observed spectral features differed across the cell, but chemical constituents in the cell nucleus and cytoplasm, such as DNA, RNA, and amino acids tyrosine and phenylalanine can be identified. Conclusions: Particularly strong field enhancement can be observed when nanoparticles form colloidal clusters. The results suggest that SERS could be a new technique for the identification of breast cancer cell. PMID:24155548

  5. Cell separation using tilted-angle standing surface acoustic waves.

    PubMed

    Ding, Xiaoyun; Peng, Zhangli; Lin, Sz-Chin Steven; Geri, Michela; Li, Sixing; Li, Peng; Chen, Yuchao; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2014-09-01

    Separation of cells is a critical process for studying cell properties, disease diagnostics, and therapeutics. Cell sorting by acoustic waves offers a means to separate cells on the basis of their size and physical properties in a label-free, contactless, and biocompatible manner. The separation sensitivity and efficiency of currently available acoustic-based approaches, however, are limited, thereby restricting their widespread application in research and health diagnostics. In this work, we introduce a unique configuration of tilted-angle standing surface acoustic waves (taSSAW), which are oriented at an optimally designed inclination to the flow direction in the microfluidic channel. We demonstrate that this design significantly improves the efficiency and sensitivity of acoustic separation techniques. To optimize our device design, we carried out systematic simulations of cell trajectories, matching closely with experimental results. Using numerically optimized design of taSSAW, we successfully separated 2- and 10-µm-diameter polystyrene beads with a separation efficiency of ∼ 99%, and separated 7.3- and 9.9-µm-polystyrene beads with an efficiency of ∼ 97%. We illustrate that taSSAW is capable of effectively separating particles-cells of approximately the same size and density but different compressibility. Finally, we demonstrate the effectiveness of the present technique for biological-biomedical applications by sorting MCF-7 human breast cancer cells from nonmalignant leukocytes, while preserving the integrity of the separated cells. The method introduced here thus offers a unique route for separating circulating tumor cells, and for label-free cell separation with potential applications in biological research, disease diagnostics, and clinical practice.

  6. Cell separation using tilted-angle standing surface acoustic waves

    PubMed Central

    Ding, Xiaoyun; Peng, Zhangli; Lin, Sz-Chin Steven; Geri, Michela; Li, Sixing; Li, Peng; Chen, Yuchao; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2014-01-01

    Separation of cells is a critical process for studying cell properties, disease diagnostics, and therapeutics. Cell sorting by acoustic waves offers a means to separate cells on the basis of their size and physical properties in a label-free, contactless, and biocompatible manner. The separation sensitivity and efficiency of currently available acoustic-based approaches, however, are limited, thereby restricting their widespread application in research and health diagnostics. In this work, we introduce a unique configuration of tilted-angle standing surface acoustic waves (taSSAW), which are oriented at an optimally designed inclination to the flow direction in the microfluidic channel. We demonstrate that this design significantly improves the efficiency and sensitivity of acoustic separation techniques. To optimize our device design, we carried out systematic simulations of cell trajectories, matching closely with experimental results. Using numerically optimized design of taSSAW, we successfully separated 2- and 10-µm-diameter polystyrene beads with a separation efficiency of ∼99%, and separated 7.3- and 9.9-µm-polystyrene beads with an efficiency of ∼97%. We illustrate that taSSAW is capable of effectively separating particles–cells of approximately the same size and density but different compressibility. Finally, we demonstrate the effectiveness of the present technique for biological–biomedical applications by sorting MCF-7 human breast cancer cells from nonmalignant leukocytes, while preserving the integrity of the separated cells. The method introduced here thus offers a unique route for separating circulating tumor cells, and for label-free cell separation with potential applications in biological research, disease diagnostics, and clinical practice. PMID:25157150

  7. Cell separation using tilted-angle standing surface acoustic waves.

    PubMed

    Ding, Xiaoyun; Peng, Zhangli; Lin, Sz-Chin Steven; Geri, Michela; Li, Sixing; Li, Peng; Chen, Yuchao; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2014-09-01

    Separation of cells is a critical process for studying cell properties, disease diagnostics, and therapeutics. Cell sorting by acoustic waves offers a means to separate cells on the basis of their size and physical properties in a label-free, contactless, and biocompatible manner. The separation sensitivity and efficiency of currently available acoustic-based approaches, however, are limited, thereby restricting their widespread application in research and health diagnostics. In this work, we introduce a unique configuration of tilted-angle standing surface acoustic waves (taSSAW), which are oriented at an optimally designed inclination to the flow direction in the microfluidic channel. We demonstrate that this design significantly improves the efficiency and sensitivity of acoustic separation techniques. To optimize our device design, we carried out systematic simulations of cell trajectories, matching closely with experimental results. Using numerically optimized design of taSSAW, we successfully separated 2- and 10-µm-diameter polystyrene beads with a separation efficiency of ∼ 99%, and separated 7.3- and 9.9-µm-polystyrene beads with an efficiency of ∼ 97%. We illustrate that taSSAW is capable of effectively separating particles-cells of approximately the same size and density but different compressibility. Finally, we demonstrate the effectiveness of the present technique for biological-biomedical applications by sorting MCF-7 human breast cancer cells from nonmalignant leukocytes, while preserving the integrity of the separated cells. The method introduced here thus offers a unique route for separating circulating tumor cells, and for label-free cell separation with potential applications in biological research, disease diagnostics, and clinical practice. PMID:25157150

  8. Characterization of the activities of actin-affecting drugs on tumor cell migration

    SciTech Connect

    Hayot, Caroline; Debeir, Olivier; Ham, Philippe van; Damme, Marc van; Kiss, Robert; Decaestecker, Christine . E-mail: cdecaes@ulb.ac.be

    2006-02-15

    Metastases kill 90% of cancer patients. It is thus a major challenge in cancer therapy to inhibit the spreading of tumor cells from primary tumor sites to those particular organs where metastases are likely to occur. Whereas the actin cytoskeleton is a key component involved in cell migration, agents targeting actin dynamics have been relatively poorly investigated. Consequently, valuable in vitro pharmacological tools are needed to selectively identify this type of agent. In response to the absence of any standardized process, the present work aims to develop a multi-assay strategy for screening actin-affecting drugs with anti-migratory potentials. To validate our approach, we used two cancer cell lines (MCF7 and A549) and three actin-affecting drugs (cytochalasin D, latrunculin A, and jasplakinolide). We quantified the effects of these drugs on the kinetics of actin polymerization in tubes (by means of spectrofluorimetry) and on the dynamics of actin cytoskeletons within whole cells (by means of fluorescence microscopy). Using quantitative videomicroscopy, we investigated the actual effects of the drugs on cell motility. Finally, the combined drug effects on cell motility and cell growth were evaluated by means of a scratch-wound assay. While our results showed concordant drug-induced effects on actin polymerization occurring in vitro in test tubes and within whole cells, the whole cell assay appeared more sensitive than the tube assay. The inhibition of actin polymerization induced by cytochalasin D was paralleled by a decrease in cell motility for both cell types. In the case of jasplakinolide, which induces actin polymerization, while it significantly enhanced the locomotion of the A549 cells, it significantly inhibited that of the MCF-7 ones. All these effects were confirmed by means of the scratch-wound assay except of the jasplakinolide-induced effects on MCF-7 cell motility. These later seemed compensated by an additional effect occurring during wound

  9. Modulators affecting the immune dialogue between human immune and colon cancer cells

    PubMed Central

    Djaldetti, Meir; Bessler, Hanna

    2014-01-01

    cells leading to a balance in cytokine production. It is conceivable that the prevalence of anti-inflammatory cytokine production by PBMC in the affected colonic mucosa will contribute to the delay, or even to halt down malignant expansion. Targeting the interplay between immune and cancer cells by mediators capable to alter cytokine secretion toward increased anti-inflammatory cytokine release by PBMC and tumor associated macrophages, may serve as an additional strategy for treatment of malignant diseases. This review will focus on the inflammatory events preceding tumorigenesis in general, and on a number of modulators capable to affect colon cancer cell-induced production of inflammatory cytokines by PBMC through alteration of the immune cross-talk between PBMC and cancer cells. PMID:24834143

  10. Factors affecting the spontaneous motion of condensate drops on superhydrophobic copper surfaces.

    PubMed

    Feng, Jie; Qin, Zhaoqian; Yao, Shuhuai

    2012-04-10

    The coalescence-induced condensate drop motion on some superhydrophobic surfaces (SHSs) has attracted increasing attention because of its potential applications in sustained dropwise condensation, water collection, anti-icing, and anticorrosion. However, an investigation of the mechanism of such self-propelled motion including the factors for designing such SHSs is still limited. In this article, we fabricated a series of superhydrophobic copper surfaces with nanoribbon structures using wet chemical oxidation followed by fluorization treatment. We then systematically studied the influence of surface roughness and the chemical properties of as-prepared surfaces on the spontaneous motion of condensate drops. We quantified the "frequency" of the condensate drop motion based on microscopic sequential images and showed that the trend of this frequency varied with the nanoribbon structure and extent of fluorination. More obvious spontaneous condensate drop motion was observed on surfaces with a higher extent of fluorization and nanostructures possessing sufficiently narrow spacing and higher perpendicularity. We attribute this enhanced drop mobility to the stable Cassie state of condensate drops in the dynamic dropwise condensation process that is determined by the nanoscale morphology and local surface energy.

  11. Colloidal mobilization of arsenic from mining-affected soils by surface runoff.

    PubMed

    Gomez-Gonzalez, Miguel Angel; Voegelin, Andreas; Garcia-Guinea, Javier; Bolea, Eduardo; Laborda, Francisco; Garrido, Fernando

    2016-02-01

    Scorodite-rich wastes left as a legacy of mining and smelting operations pose a threat to environmental health. Colloids formed by the weathering of processing wastes may control the release of arsenic (As) into surface waters. At a former mine site in Madrid (Spain), we investigated the mobilization of colloidal As by surface runoff from weathered processing wastes and from sediments in the bed of a draining creek and a downstream sedimentation-pond. Colloids mobilized by surface runoff during simulated rain events were characterized for their composition, structure and mode of As uptake using asymmetric flow field-flow fractionation coupled to inductively plasma mass spectrometry (AF4-ICP-MS) and X-ray absorption spectroscopy (XAS) at the As and Fe K-edges. Colloidal scorodite mobilized in surface runoff from the waste pile is acting as a mobile As carrier. In surface runoff from the river bed and the sedimentation pond, ferrihydrite was identified as the dominant As-bearing colloidal phase. The results from this study suggest that mobilization of As-bearing colloids by surface runoff may play an important role in the dispersion of As from metallurgical wastes deposited above ground and needs to be considered in risk assessment.

  12. Colloidal mobilization of arsenic from mining-affected soils by surface runoff.

    PubMed

    Gomez-Gonzalez, Miguel Angel; Voegelin, Andreas; Garcia-Guinea, Javier; Bolea, Eduardo; Laborda, Francisco; Garrido, Fernando

    2016-02-01

    Scorodite-rich wastes left as a legacy of mining and smelting operations pose a threat to environmental health. Colloids formed by the weathering of processing wastes may control the release of arsenic (As) into surface waters. At a former mine site in Madrid (Spain), we investigated the mobilization of colloidal As by surface runoff from weathered processing wastes and from sediments in the bed of a draining creek and a downstream sedimentation-pond. Colloids mobilized by surface runoff during simulated rain events were characterized