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Sample records for affect cell surface

  1. Cell surface lectin array: parameters affecting cell glycan signature.

    PubMed

    Landemarre, Ludovic; Cancellieri, Perrine; Duverger, Eric

    2013-04-01

    Among the "omics", glycomics is one of the most complex fields and needs complementary strategies of analysis to decipher the "glycan dictionary". As an alternative method, which has developed since the beginning of the 21st century, lectin array technology could generate relevant information related to glycan motifs, accessibility and a number of other valuable insights from molecules (purified and non-purified) or cells. Based on a cell line model, this study deals with the key parameters that influence the whole cell surface glycan interaction with lectin arrays and the consequences on the interpretation and reliability of the results. The comparison between the adherent and suspension forms of Chinese Hamster Ovary (CHO) cells, showed respective glycan signatures, which could be inhibited specifically by neoglycoproteins. The modifications of the respective glycan signatures were also revealed according to the detachment modes and cell growth conditions. Finally the power of lectin array technology was highlighted by the possibility of selecting and characterizing a specific clone from the mother cell line, based on the slight difference determination in the respective glycan signatures. PMID:22899543

  2. 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. PMID:24027204

  3. 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.

  4. Surface-Driven Collagen Self-Assembly Affects Early Osteogenic Stem Cell Signaling.

    PubMed

    Razafiarison, Tojo; Silván, Unai; Meier, Daniela; Snedeker, Jess G

    2016-06-01

    This study reports how extracellular matrix (ECM) ligand self-assembly on biomaterial surfaces and the resulting nanoscale architecture can drive stem cell behavior. To isolate the biological effects of surface wettability on protein deposition, folding, and ligand activity, a polydimethylsiloxane (PDMS)-based platform was developed and characterized with the ability to tune wettability of elastomeric substrates with otherwise equivalent topology, ligand loading, and mechanical properties. Using this platform, markedly different assembly of covalently bound type I collagen monomers was observed depending on wettability, with hydrophobic substrates yielding a relatively rough layer of collagen aggregates compared to a smooth collagen layer on more hydrophilic substrates. Cellular and molecular investigations with human bone marrow stromal cells revealed higher osteogenic differentiation and upregulation of focal adhesion-related components on the resulting smooth collagen layer coated substrates. The initial collagen assembly driven by the PDMS surface directly affected α1β1 integrin/discoidin domain receptor 1 signaling, activation of the extracellular signal-regulated kinase/mitogen activated protein kinase pathway, and ultimately markers of osteogenic stem cell differentiation. We demonstrate for the first time that surface-driven ligand assembly on material surfaces, even on materials with otherwise identical starting topographies and mechanical properties, can dominate the biomaterial surface-driven cell response. PMID:27125602

  5. Cell-surface serglycin promotes adhesion of myeloma cells to collagen type I and affects the expression of matrix metalloproteinases.

    PubMed

    Skliris, Antonis; Labropoulou, Vassiliki T; Papachristou, Dionysios J; Aletras, Alexios; Karamanos, Nikos K; Theocharis, Achilleas D

    2013-05-01

    Serglycin (SG) is mainly expressed by hematopoetic cells as an intracellular proteoglycan. Multiple myeloma cells constitutively secrete SG, which is also localized on the cell surface in some cell lines. In this study, SG isolated from myeloma cells was found to interact with collagen type I (Col I), which is a major bone matrix component. Notably, myeloma cells positive for cell-surface SG (csSG) adhered significantly to Col I, compared to cells lacking csSG. Removal of csSG by treatment of the cells with chondroitinase ABC or blocking of csSG by an SG-specific polyclonal antibody significantly reduced the adhesion of myeloma cells to Col I. Significant up-regulation of expression of the matrix metalloproteinases MMP-2 and MMP-9 at both the mRNA and protein levels was observed when culturing csSG-positive myeloma cells on Col I-coated dishes or in the presence of soluble Col I. MMP-9 and MMP-2 were also expressed in increased amounts by myeloma cells in the bone marrow of patients with multiple myeloma. Our data indicate that csSG of myeloma cells affects key functional properties, such as adhesion to Col I and the expression of MMPs, and imply that csSG may serve as a potential prognostic factor and/or target for pharmacological interventions in multiple myeloma. PMID:23387827

  6. Surface Chemical Gradient Affects the Differentiation of Human Adipose-Derived Stem Cells via ERK1/2 Signaling Pathway.

    PubMed

    Liu, Xujie; Shi, Shengjun; Feng, Qingling; Bachhuka, Akash; He, Wei; Huang, Qianli; Zhang, Ranran; Yang, Xing; Vasilev, Krasimir

    2015-08-26

    To understand the role of surface chemistry on cell behavior and the associated molecular mechanisms, we developed and utilized a surface chemical gradient of amine functional groups by carefully adjusting the gas composition of 1,7-octadiene (OD) and allylamine (AA) of the plasma phase above a moving substrate. The chemical gradient surface used in the present work shows an increasing N/C ratio and wettability from the OD side toward the AA side with no change in surface topography. Under standard culture conditions (with serum), human adipose-derived stem cells (hASCs) adhesion and spreading area increased toward the AA side of the gradient. However, there were no differences in cell behavior in the absence of serum. These results, supported by the trends in proteins adsorption on the gradient surface, demonstrated that surface chemistry affects the response of hASCs through cell-adhesive serum proteins, rather than interacting directly with the cells. The expression of p-ERK and the osteogenic differentiation increased toward the AA side of the gradient, while adipogenic differentiation decreased in the same direction; however, when the activation of ERK1/2 was blocked by PD98059, the levels of osteogenic or adipogenic differentiation on different regions of the chemical gradient were the same. This indicates that ERK1/2 may be an important downstream signaling pathway of surface chemistry directed stem cell fate. PMID:26237746

  7. 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

  8. The Presence of VEGF Receptors on the Luminal Surface of Endothelial Cells Affects VEGF Distribution and VEGF Signaling

    PubMed Central

    Stefanini, Marianne O.; Wu, Florence T. H.; Mac Gabhann, Feilim; Popel, Aleksander S.

    2009-01-01

    Vascular endothelial growth factor (VEGF) is a potent cytokine that binds to specific receptors on the endothelial cells lining blood vessels. The signaling cascade triggered eventually leads to the formation of new capillaries, a process called angiogenesis. Distributions of VEGF receptors and VEGF ligands are therefore crucial determinants of angiogenic events and, to our knowledge, no quantification of abluminal vs. luminal receptors has been performed. We formulate a molecular-based compartment model to investigate the VEGF distribution in blood and tissue in humans and show that such quantification would lead to new insights on angiogenesis and VEGF-dependent diseases. Our multiscale model includes two major isoforms of VEGF (VEGF121 and VEGF165), as well as their receptors (VEGFR1 and VEGFR2) and the non-signaling co-receptor neuropilin-1 (NRP1). VEGF can be transported between tissue and blood via transendothelial permeability and the lymphatics. VEGF receptors are located on both the luminal and abluminal sides of the endothelial cells. In this study, we analyze the effects of the VEGF receptor localization on the endothelial cells as well as of the lymphatic transport. We show that the VEGF distribution is affected by the luminal receptor density. We predict that the receptor signaling occurs mostly on the abluminal endothelial surface, assuming that VEGF is secreted by parenchymal cells. However, for a low abluminal but high luminal receptor density, VEGF binds predominantly to VEGFR1 on the abluminal surface and VEGFR2 on the luminal surface. Such findings would be pertinent to pathological conditions and therapies related to VEGF receptor imbalance and overexpression on the endothelial cells and will hopefully encourage experimental receptor quantification for both luminal and abluminal surfaces on endothelial cells. PMID:20041209

  9. 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

  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. 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

  13. A dimeric peptide with erythropoiesis-stimulating activity uniquely affects erythropoietin receptor ligation and cell surface expression.

    PubMed

    Verma, Rakesh; Green, Jennifer M; Schatz, Peter J; Wojchowski, Don M

    2016-08-01

    Erythropoiesis-stimulating agents (ESAs) that exert long-acting antianemia effects have been developed recently, but their mechanisms are poorly understood. Analyses reveal unique erythropoietin receptor (EPOR)-binding properties for one such ESA, the synthetic EPOR agonist peginesatide. Compared with recombinant human EPO and darbepoietin, peginesatide exhibited a slow on rate, but sustained EPOR residency and resistant displacement. In EPO-dependent human erythroid progenitor UT7epo cells, culture in peginesatide unexpectedly upmodulated endogenous cell surface EPOR levels with parallel increases in full-length EPOR-68K levels. These unique properties are suggested to contribute to the durable activity of this (and perhaps additional) dimeric peptide hematopoietic growth factor receptor agonist. PMID:27174804

  14. Cell surface protein C23 affects EGF-EGFR induced activation of ERK and PI3K-AKT pathways.

    PubMed

    Lv, Shunzeng; Dai, Congxin; Liu, Yuting; Sun, Bowen; Shi, Ranran; Han, Mingzhi; Bian, Ruixiang; Wang, Renzhi

    2015-02-01

    The epidermal growth factor (EGF) pathway has been reported as canonical causes in cancer development. Meanwhile, the involvement of C23 in multiple signaling pathways has been also investigated (Lv et al., 2014). However, the effect of C23 on EGF pathway in glioblastoma is not fully characterized. In the present study, C23 and the epidermal growth factor receptor (EGFR) of U251 cell line were inhibited by C23 and EGFR antibodies, respectively; and then C23 and EGFR siRNAs were used to knock down endogenous C23 and EGFR, respectively. In addition, soft-agar and MTT assay were also introduced. Compared with control, either C23 or EGFR antibodies efficiently repressed the phosphorylation levels of ERK1/2 (p<0.000) and AKT (p<0.000). Similarly, either C23 or EGFR siRNAs indeed resulted in C23 and EGFR knockdown, and further suppressed the expression of p-ERK1/2 and p-AKT. Most importantly, immunoprecipitation revealed C23 interacted with EGFR once U251 was exposed to EGF treatment. In addition, the MTT and soft-agar assay also identified that C23 or EGFR siRNAs could obviously affected cell growth (p=0.004) and invasiveness, as cell viability and colony formation decreased markedly. Our results suggest that C23 plays a crucial role in activation of EGF-induced ERK and PI3K-AKT pathways via interacting with EGFR; furthermore, C23 could be indicative of an important factor in glioblastoma development and a useful target for glioblastoma treatment. PMID:25015231

  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 ability of Hepatitis B surface antigen DNA vaccine to elicit cell-mediated immune responses, but not antibody responses, was affected by the deglysosylation of S antigen.

    PubMed

    Xing, Yiping; Huang, Zuhu; Lin, Yan; Li, Jun; Chou, Te-Hui; Lu, Shan; Wang, Shixia

    2008-09-19

    Hepatitis B Virus (HBV) infection remains a major worldwide infectious disease with serious long-term morbidity and mortality. The limited selections of drug treatment are not able to control the progress of disease in people with active and persistent HBV infection. Immunotherapy to control the degree of viral infection is one possible alternative solution to this challenge. HBV DNA vaccines, with their strong ability to induce cell-mediated immune responses, offer an attractive option. HBV surface protein is important in viral immunity. Re-establishing anti-S immunity in chronic HBV infected patients will bring significant benefit to the patients. Previous studies have shown that HBV S DNA vaccines are immunogenic in a number of animal studies. In the current study, we further investigated the effect of glycosylation to the expression and immunogenicity of S DNA vaccines. Our results demonstrate that deglycosylation at the two potential N-linked glycosylation sites in S protein resulted in a significant decrease of S-specific cell-mediated immune responses, but did not affect anti-S antibody responses. This finding provides important direction to the development of S DNA vaccines to elicit the optimal and balanced antibody and cell-mediated immune responses to treat people with HBV chronic infections. PMID:18462847

  17. Effect of surface conditions affecting voltage breakdowns

    NASA Astrophysics Data System (ADS)

    Flauta, Randolph; Aghazarian, Maro; Caughman, John; Ruzic, David

    2008-11-01

    The maximum power transferred by ion cyclotron range of frequency (ICRF) antennas is dependent on the breakdown threshold when operated at high voltages. The voltage that these antennas can withstand is lowered and hence breakdowns occur due to many factors. The Surface Plasma Arcs by Radiofrequency - Control Study or SPARCS facility has a 0-15kV DC power supply to deliver power to flat cathode surface and semi-spherical anode made of Cu and Al under 10-8-10-6 torr vacuum conditions. The effects of different surface conditions on the breakdown threshold were then investigated. Also, as the ICRF antennas used for heating plasmas may come into contact with contaminants from the plasma, Li was also deposited on the cathode surface through in-situ evaporation coating and its effect on the breakdown threshold was investigated. Results on surface roughness showed no significant dependence of the breakdown threshold on macroscopic surface roughness in the cathode arithmetic roughness range of ˜77-1139nm. Microscopic surface features such as grain boundaries, impurities and imperfections may play a more visible role in affecting the vacuum breakdown.

  18. 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

  19. Autosomal Mutations Affecting Adhesion between Wing Surfaces in Drosophila Melanogaster

    PubMed Central

    Prout, M.; Damania, Z.; Soong, J.; Fristrom, D.; Fristrom, J. W.

    1997-01-01

    Integrins are evolutionarily conserved transmembrane α,β heterodimeric receptors involved in cell-to-matrix and cell-to-cell adhesions. In Drosophila the position-specific (PS) integrins mediate the formation and maintenance of junctions between muscle and epidermis and between the two epidermal wing surfaces. Besides integrins, other proteins are implicated in integrin-dependent adhesion. In Drosophila, somatic clones of mutations in PS integrin genes disrupt adhesion between wing surfaces to produce wing blisters. To identify other genes whose products function in adhesion between wing surfaces, we conducted a screen for autosomal mutations that produce blisters in somatic wing clones. We isolated 76 independent mutations in 25 complementation groups, 15 of which contain more than one allele. Chromosomal sites were determined by deficiency mapping, and genetic interactions with mutations in the β(PS) integrin gene myospheroid were investigated. Mutations in four known genes (blistered, Delta, dumpy and mastermind) were isolated. Mutations were isolated in three new genes (piopio, rhea and steamer duck) that affect myo-epidermal junctions or muscle function in embryos. Mutations in three other genes (kakapo, kiwi and moa) may also affect cell adhesion or muscle function at hatching. These new mutants provide valuable material for the study of integrin-dependent cell-to-cell adhesion. PMID:9136017

  20. Isolation of a protein-containing cell surface component from Streptococcus sanguis which affects its adherence to saliva-coated hydroxyapatite.

    PubMed Central

    Liljemark, W F; Bloomquist, C G

    1981-01-01

    The isolation and partial characterization of a protein-containing cell surface component from Streptococcus sanguis which blocks the adherence of this microbe to saliva-coated hydroxyapatite are described. Several methods of extraction were attempted. Sonication of whole cells and cell walls proved to be the most successful and yielded biologically active adherence-blocking components. The adherence-blocking ability of these components was effective in intraspecies blocking experiments. The extract obtained from cell walls of S. sanguis was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and shown to contain one major and two to three minor bands when stained with Coomassie blue. The molecular weight of the major band was estimated to be 70,000 to 90,000. Gel filtration of the sonified cell wall extract on 10% agarose yielded two active adherence-blocking peaks, the void volume and a second peak. Images PMID:6273317

  1. 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

  2. Cell Surface Analysis Techniques: What Do Cell Preparation Protocols Do to Cell Surface Properties?

    PubMed Central

    Pembrey, Richard S.; Marshall, Kevin C.; Schneider, René P.

    1999-01-01

    Cell surface analysis often requires manipulation of cells prior to examination. The most commonly employed procedures are centrifugation at different speeds, changes of media during washing or final resuspension, desiccation (either air drying for contact angle measurements or freeze-drying for sensitive spectroscopic analysis, such as X-ray photoelectron spectroscopy), and contact with hydrocarbon (hydrophobicity assays). The effects of these procedures on electrophoretic mobility, adhesion to solid substrata, affinity to a number of Sepharose columns, structural integrity, and cell viability were systematically investigated for a range of model organisms, including carbon- and nitrogen-limited Psychrobacter sp. strain SW8 (glycocalyx-bearing cells), Escherichia coli (gram-negative cells without a glycocalyx), and Staphylococcus epidermidis (gram-positive cells without a glycocalyx). All of the cell manipulation procedures severely modified the physicochemical properties of cells, but with each procedure some organisms were more susceptible than others. Considerable disruption of cell surfaces occurred when organisms were placed in contact with a hydrocarbon (hexadecane). The majority of cells became nonculturable after air drying and freeze-drying. Centrifugation at a high speed (15,000 × g) modified many cell surface parameters significantly, although cell viability was considerably affected only in E. coli. The type of washing or resuspension medium had a strong influence on the values of cell surface parameters, particularly when high-salt solutions were compared with low-salt buffers. The values for parameters obtained with different methods that allegedly measure similar cell surface properties did not correlate for most cells. These results demonstrate that the methods used to prepare cells for cell surface analysis need to be critically investigated for each microorganism so that the final results obtained reflect the nature of the in situ microbial cell

  3. 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.

  4. 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. PMID:26556312

  5. How surface damage removal affects fatigue life

    NASA Technical Reports Server (NTRS)

    Jeelani, S.; Scott, M. A.

    1988-01-01

    The effect of the removal of work hardened surface layers from specimens of 2024-T4 aluminum alloy and AISI-4130 steel on their fatigue lives has been investigated. Specimens were fatigued at selected stress levels for a given number of cycles, and the surface layer was removed followed by subsequent fatigue cycling. Results confirm that when a material is subjected to fatigue loading, damage accumulates in the surface layers in the form of work hardening. Removal of the surface layer brings the specimen back to its pre-fatigued condition.

  6. 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

  7. Produce Surface Characteristics Affect Product Quality and Safety

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The surface characteristics of fresh-cut fruits and vegetables vary largely among produce types, maturities and processing procedure. Studies have shown that the surface topography of produce significantly affected adherence, attachment, and biofilm formation of bacteria, as well as their removal a...

  8. Physical parameters affecting living cells in space.

    PubMed

    Langbein, D

    1986-01-01

    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. PMID:11537842

  9. The cell-surface interaction.

    PubMed

    Hayes, J S; Czekanska, E M; Richards, R G

    2012-01-01

    The realm of surface-dependent cell and tissue responses is the foundation of orthopaedic-device-related research. However, to design materials that elicit specific responses from tissues is a complex proposition mainly because the vast majority of the biological principles controlling the interaction of cells with implants remain largely ambiguous. Nevertheless, many surface properties, such as chemistry and topography, can be manipulated in an effort to selectively control the cell-material interaction. On the basis of this information there has been much research in this area, including studies focusing on the structure and composition of the implant interface, optimization of biological and chemical coatings and elucidation of the mechanisms involved in the subsequent cell-material interactions. Although a wealth of information has emerged, it also advocates the complexity and dynamism of the cell-material interaction. Therefore, this chapter aims to provide the reader with an introduction to the basic concepts of the cell-material interaction and to provide an insight into the factors involved in determining the cell and tissue response to specific surface features, with specific emphasis on surface microtopography. PMID:21984613

  10. 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 ...

  11. 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.

  12. Nanocontact electrification: patterned surface charges affecting adhesion, transfer, and printing.

    PubMed

    Cole, Jesse J; Barry, Chad R; Knuesel, Robert J; Wang, Xinyu; Jacobs, Heiko O

    2011-06-01

    Contact electrification creates an invisible mark, overlooked and often undetected by conventional surface spectroscopic measurements. It impacts our daily lives macroscopically during electrostatic discharge and is equally relevant on the nanoscale in areas such as soft lithography, transfer, and printing. This report describes a new conceptual approach to studying and utilizing contact electrification beyond prior surface force apparatus and point-contact implementations. Instead of a single point contact, our process studies nanocontact electrification that occurs between multiple nanocontacts of different sizes and shapes that can be formed using flexible materials, in particular, surface-functionalized poly(dimethylsiloxane) (PDMS) stamps and other common dielectrics (PMMA, SU-8, PS, PAA, and SiO(2)). Upon the formation of conformal contacts and forced delamination, contacted regions become charged, which is directly observed using Kelvin probe force microscopy revealing images of charge with sub-100-nm lateral resolution. The experiments reveal chemically driven interfacial proton exchange as the dominant charging mechanism for the materials that have been investigated so far. The recorded levels of uncompensated charges approach the theoretical limit that is set by the dielectric breakdown strength of the air gap that forms as the surfaces are delaminated. The macroscopic presence of the charges is recorded using force-distance curve measurements involving a balance and a micromanipulator to control the distance between the delaminated objects. Coulomb attraction between the delaminated surfaces reaches 150 N/m(2). At such a magnitude, the force finds many applications. We demonstrate the utility of printed charges in the fields of (i) nanoxerography and (ii) nanotransfer printing whereby the smallest objects are ∼10 nm in diameter and the largest objects are in the millimeter to centimeter range. The printed charges are also shown to affect the electronic

  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. 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.

  15. Exploration mode affects visuohaptic integration of surface orientation.

    PubMed

    Plaisier, Myrthe A; van Dam, Loes C J; Glowania, Catharina; Ernst, Marc O

    2014-01-01

    We experience the world mostly in a multisensory fashion using a combination of all of our senses. Depending on the modality we can select different exploration strategies for extracting perceptual information. For instance, using touch we can enclose an object in our hand to explore parts of the object in parallel. Alternatively, we can trace the object with a single finger to explore its parts in a serial fashion. In this study we investigated whether the exploration mode (parallel vs. serial) affects the way sensory signals are combined. To this end, participants visually and haptically explored surfaces that varied in roll angle and indicated which side of the surface was perceived as higher. In Experiment 1, the exploration mode was the same for both modalities (i.e., both parallel or both serial). In Experiment 2, we introduced a difference in exploration mode between the two modalities (visual exploration was parallel while haptic exploration was serial or vice versa). The results showed that visual and haptic signals were combined in a statistically optimal fashion only when the exploration modes were the same. In case of an asymmetry in the exploration modes across modalities, integration was suboptimal. This indicates that spatial-temporal discrepancies in the acquisition of information in the two senses (i.e., haptic and visual) can lead to the breakdown of sensory integration. PMID:25413627

  16. 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

  17. Implant Surface Design Regulates Mesenchymal Stem Cell Differentiation and Maturation.

    PubMed

    Boyan, B D; Cheng, A; Olivares-Navarrete, R; Schwartz, Z

    2016-03-01

    Changes in dental implant materials, structural design, and surface properties can all affect biological response. While bulk properties are important for mechanical stability of the implant, surface design ultimately contributes to osseointegration. This article reviews the surface parameters of dental implant materials that contribute to improved cell response and osseointegration. In particular, we focus on how surface design affects mesenchymal cell response and differentiation into the osteoblast lineage. Surface roughness has been largely studied at the microscale, but recent studies have highlighted the importance of hierarchical micron/submicron/nanosurface roughness, as well as surface roughness in combination with surface wettability. Integrins are transmembrane receptors that recognize changes in the surface and mediate downstream signaling pathways. Specifically, the noncanonical Wnt5a pathway has been implicated in osteoblastic differentiation of cells on titanium implant surfaces. However, much remains to be elucidated. Only recently have studies been conducted on the differences in biological response to implants based on sex, age, and clinical factors; these all point toward differences that advocate for patient-specific implant design. Finally, challenges in implant surface characterization must be addressed to optimize and compare data across studies. An understanding of both the science and the biology of the materials is crucial for developing novel dental implant materials and surface modifications for improved osseointegration. PMID:26927483

  18. Probe microscopy: Scanning below the cell surface

    NASA Astrophysics Data System (ADS)

    Sahin, Ozgur

    2008-08-01

    Conventional atomic force microscopy probes only the surface of specimens. A related technique called scanning near-field ultrasonic holography can now image nanoparticles buried below the surfaces of cells, which could prove useful in nanotoxicology.

  19. 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.

  20. Factors Affecting Polymer Electrolyte Fuel Cells Performance and Reproducibility

    SciTech Connect

    Moller-Holst S.

    1998-11-01

    Development of fuel cells is often based on small-scale laboratory studies. Due to limited time and budgets, a minimum number of cells are usually prepared and tested, thus, conclusions about improved performance are often drawn from studies of a few cells. Generally, statistics showing the significance of an effect are seldom reported. In this work a simple PEM fuel cell electrode optimization experiment is used as an example to illustrate the importance of statistical evaluation of factors affecting cell performance. The use of fractional factorial design of experiments to reduce the number of cells that have to be studied is also addressed.

  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. Surface Functionalization for Protein and Cell Patterning

    NASA Astrophysics Data System (ADS)

    Colpo, Pascal; Ruiz, Ana; Ceriotti, Laura; Rossi, François

    The interaction of biological systems with synthetic material surfaces is an important issue for many biological applications such as implanted devices, tissue engineering, cell-based sensors and assays, and more generally biologic studies performed ex vivo. To ensure reliable outcomes, the main challenge resides in the ability to design and develop surfaces or artificial micro-environment that mimic 'natural environment' in interacting with biomolecules and cells without altering their function and phenotype. At this effect, microfabrication, surface chemistry and material science play a pivotal role in the design of advanced in-vitro systems for cell culture applications. In this chapter, we discuss and describe different techniques enabling the control of cell-surface interactions, including the description of some techniques for immobilization of ligands for controlling cell-surface interactions and some methodologies for the creation of well confined cell rich areas.

  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. 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

  5. The cell surface GRP78 facilitates the invasion of hepatocellular carcinoma cells.

    PubMed

    Zhang, Xiu-Xiu; Li, Hong-Dan; Zhao, Song; Zhao, Liang; Song, Hui-Juan; Wang, Guan; Guo, Qing-Jun; Luan, Zhi-Dong; Su, Rong-Jian

    2013-01-01

    Invasion is a major characteristic of hepatocellular carcinoma and one of the main causes of refractory to treatment. We have previously reported that GRP78 promotes the invasion of hepatocellular carcinoma although the mechanism underlying this change remains uncertain. In this paper, we explored the role of the cell surface GRP78 in the regulation of cancer cell invasion in hepatocellular carcinoma cells. We found that neutralization of the endogenous cell surface GRP78 with the anti-GRP78 antibody inhibited the adhesion and invasion in hepatocellular carcinoma cell lines Mahlavu and SMMC7721. However, forced expression of the cell surface GRP78 facilitated the adhesion and invasion in SMMC7721. We further demonstrated that inhibition of the endogenous cell surface GRP78 specifically inhibited the secretion and activity of MMP-2 but did not affect the secretion and activity of MMP-9. We also found that inhibition of the cell surface GRP78 increased E-Cadherin expression and decreased N-Cadherin level. On the contrary, forced expression of the cell surface GRP78 increased N-Cadherin expression and decreased E-Cadherin level, suggesting that the cell surface GRP78 plays critical role in the regulation of EMT process. These findings suggest that the cell surface GRP78 plays a stimulatory role in the invasion process and may be a potential anti-invasion target for the treatment of hepatocellular carcinoma. PMID:24383061

  6. CDK5 interacts with Slo and affects its surface expression and kinetics through direct phosphorylation

    PubMed Central

    Bai, Jun-Ping; Surguchev, Alexei; Joshi, Powrnima; Gross, Liza

    2012-01-01

    Large-conductance calcium-activated potassium (BK) channels are ubiquitous and play an important role in a number of diseases. In hair cells of the ear, they play a critical role in electrical tuning, a mechanism of frequency discrimination. These channels show variable kinetics and expression along the tonotopic axis. Although the molecular underpinnings to its function in hair cells are poorly understood, it is established that BK channels consist of a pore-forming α-subunit (Slo) and a number of accessory subunits. Here we identify CDK5, a member of the cyclin-dependent kinase family, as an interacting partner of Slo. We show CDK5 to be present in hair cells and expressed in high concentrations in the cuticular plate and in the circumferential zone. In human embryonic kidney cells, we show that CDK5 inhibits surface expression of Slo by direct phosphorylation of Slo. Similarly, we note that CDK5 affects Slo voltage activation and deactivation kinetics, by a direct phosphorylation of T847. Taken together with its increasing expression along the tonotopic axis, these data suggest that CDK5 likely plays a critical role in electrical tuning and surface expression of Slo in hair cells. PMID:22094329

  7. Factors affecting response of surface waters to acidic deposition

    SciTech Connect

    Turner, R.S.; Johnson, D.W.; Elwood, J.W.; Van Winkle, W.; Clapp, R.B.; Reuss, J.O.

    1986-04-01

    Knowledge of watershed hydrology and of the biogeochemical reactions and elemental pools and fluxes occurring in watersheds can be used to classify the response of watersheds and surface waters to acidic deposition. A conceptual mosel is presented for classifying watersheds into those for which (1) surface water chemistry will change rapidly with deposition quality (direct response) (2) surface water chemistry will change only slowly over time (delayed response), and (3) surface water chemistry will not change significantly, even with continued acidic deposition (capacity-protected). Techniques and data available for classification of all watersheds in a region into these categories are discussed.

  8. The Aerodynamic Characteristics of Airfoils as Affected by Surface Roughness

    NASA Technical Reports Server (NTRS)

    HOCKER RAY W

    1933-01-01

    The effect on airfoil characteristics of surface roughness of varying degrees and types at different locations on an airfoil was investigated at high values of the Reynolds number in a variable density wind tunnel. Tests were made on a number of National Advisory Committee for Aeronautics (NACA) 0012 airfoil models on which the nature of the surface was varied from a rough to a very smooth finish. The effect on the airfoil characteristics of varying the location of a rough area in the region of the leading edge was also investigated. Airfoils with surfaces simulating lap joints were also tested. Measurable adverse effects were found to be caused by small irregularities in airfoil surfaces which might ordinarily be overlooked. The flow is sensitive to small irregularities of approximately 0.0002c in depth near the leading edge. The tests made on the surfaces simulating lap joints indicated that such surfaces cause small adverse effects. Additional data from earlier tests of another symmetrical airfoil are also included to indicate the variation of the maximum lift coefficient with the Reynolds number for an airfoil with a polished surface and with a very rough one.

  9. How Chimeric Antigen Receptor Design Affects Adoptive T Cell Therapy.

    PubMed

    Gacerez, Albert T; Arellano, Benjamine; Sentman, Charles L

    2016-12-01

    Chimeric antigen receptor (CAR) T cells have been developed to treat tumors and have shown great success against B cell malignancies. Exploiting modular designs and swappable domains, CARs can target an array of cell surface antigens and, upon receptor-ligand interactions, direct signaling cascades, thereby driving T cell effector functions. CARs have been designed using receptors, ligands, or scFv binding domains. Different regions of a CAR have each been found to play a role in determining the overall efficacy of CAR T cells. Therefore, this review provides an overview of CAR construction and common designs. Each CAR region is discussed in the context of its importance to a CAR's function. Additionally, the review explores how various engineering strategies have been applied to CAR T cells in order to regulate CAR T cell function and activity. J. Cell. Physiol. 231: 2590-2598, 2016. © 2016 Wiley Periodicals, Inc. PMID:27163336

  10. The FRIABLE1 Gene Product Affects Cell Adhesion in Arabidopsis

    PubMed Central

    Neumetzler, Lutz; Humphrey, Tania; Lumba, Shelley; Snyder, Stephen; Yeats, Trevor H.; Usadel, Björn; Vasilevski, Aleksandar; Patel, Jignasha; Rose, Jocelyn K. C.; Persson, Staffan; Bonetta, Dario

    2012-01-01

    Cell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1), was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic defects in organ separation. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246). Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion. PMID:22916179

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

    PubMed Central

    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

  12. 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.

  13. Exposure of phosphatidylserine on the cell surface.

    PubMed

    Nagata, S; Suzuki, J; Segawa, K; Fujii, T

    2016-06-01

    Phosphatidylserine (PtdSer) is a phospholipid that is abundant in eukaryotic plasma membranes. An ATP-dependent enzyme called flippase normally keeps PtdSer inside the cell, but PtdSer is exposed by the action of scramblase on the cell's surface in biological processes such as apoptosis and platelet activation. Once exposed to the cell surface, PtdSer acts as an 'eat me' signal on dead cells, and creates a scaffold for blood-clotting factors on activated platelets. The molecular identities of the flippase and scramblase that work at plasma membranes have long eluded researchers. Indeed, their identity as well as the mechanism of the PtdSer exposure to the cell surface has only recently been revealed. Here, we describe how PtdSer is exposed in apoptotic cells and in activated platelets, and discuss PtdSer exposure in other biological processes. PMID:26891692

  14. Pretreatment of amphiphilic comb polymer surfaces dramatically affects protein adsorption.

    PubMed

    Zhang, Zhanping; Ma, Hongwei; Hausner, Douglas B; Chilkoti, Ashutosh; Beebe, Thomas P

    2005-01-01

    New applications in regenerative biotechnology require the ability to understand and control protein-surface interactions on micrometer and submicrometer length scales. Evidence presented here shows that micropatterned amphiphilic comb polymer films exhibit a pretreatment-dependent behavior with respect to protein adsorption for the proteins fibronectin, laminin, and for serum. A micropatterned surface, consisting of protein-reactive regions, separated by comb polymer, was created and tested for protein adsorption using the surface-sensitive imaging tool TOF-SIMS. Immersion of micropatterned surfaces in solutions of fibronectin or laminin resulted in uniform protein coverage on both the comb polymer and protein-reactive regions. However, preimmersion of similarly patterned surfaces in water for 2 h prior to protein incubation was found to dramatically improve the protein-resistant properties of the comb polymer regions. These results are consistent with poly(ethylene glycol) (PEG) side chain reorientation and/or hydration and poly(methyl methacrylate) (PMMA) backbone segregation away from the interface region. PMID:16283770

  15. Solar cell having improved back surface reflector

    NASA Astrophysics Data System (ADS)

    Chai, A. T.

    1982-10-01

    The operating temperature is reduced and the output of a solar cell is increased by using a solar cell which carries electrodes in a grid finger pattern on its back surface. These electrodes are sintered at the proper temperature to provide good ohmic contact. After sintering, a reflective material is deposited on the back surface by vacuum evaporation. Thus, the application of the back surface reflector is separate from the back contact formation. Back surface reflectors formed in conjunction with separate grid finger configuration back contacts are more effective than those formed by full back metallization of the reflector material.

  16. 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.

  17. Directing neuronal cell growth on implant material surfaces by microstructuring.

    PubMed

    Reich, Uta; Fadeeva, Elena; Warnecke, Athanasia; Paasche, Gerrit; Müller, Peter; Chichkov, Boris; Stöver, Timo; Lenarz, Thomas; Reuter, Günter

    2012-05-01

    For best hearing sensation, electrodes of auditory prosthesis must have an optimal electrical contact to the respective neuronal cells. To improve the electrode-nerve interface, microstructuring of implant surfaces could guide neuronal cells toward the electrode contact. To this end, femtosecond laser ablation was used to generate linear microgrooves on the two currently relevant cochlear implant materials, silicone elastomer and platinum. Silicone surfaces were structured by two different methods, either directly, by laser ablation or indirectly, by imprinting using laser-microstructured molds. The influence of surface structuring on neurite outgrowth was investigated utilizing a neuronal-like cell line and primary auditory neurons. The pheochromocytoma cell line PC-12 and primary spiral ganglion cells were cultured on microstructured auditory implant materials. The orientation of neurite outgrowth relative to the microgrooves was determined. Both cell types showed a preferred orientation in parallel to the microstructures on both, platinum and on molded silicone elastomer. Interestingly, microstructures generated by direct laser ablation of silicone did not influence the orientation of either cell type. This shows that differences in the manufacturing procedures can affect the ability of microstructured implant surfaces to guide the growth of neurites. This is of particular importance for clinical applications, since the molding technique represents a reproducible, economic, and commercially feasible manufacturing procedure for the microstructured silicone surfaces of medical implants. PMID:22287482

  18. 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

  19. 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.

  20. 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.

  1. Surface wind observations affected by agricultural development over Northwest China

    NASA Astrophysics Data System (ADS)

    Han, Songjun; Tang, Qiuhong; Zhang, Xuezhen; Xu, Di; Kou, Lihang

    2016-05-01

    Meteorological stations in Northwest China are surrounded by large proportions of cultivated land. The relations between the change of surface wind speed and the cultivated land fractions (CF) within a 4 km radius at 135 meteorological stations over arid Northwest China are investigated. Stations with larger CF experienced larger declines in surface wind speed from 1960 to 2007. Compared with the wind speed variation in the Tibetan Plateau where agricultural development is negligible, stations with low CF show similar variation, whereas the wind speed at stations with large CF illustrates a sharp decrease in the 1970s–1980s, during which irrigated agriculture developed rapidly. The observed wind speed at the station surrounded by irrigated fields in the Jingtai Irrigation District, shows a rapid wind speed decrease during the same period when the irrigated area expanded. By contrast, rapid wind decrease is not observed at a nearby station with minimal influence of agricultural development.

  2. Functional dynamics of cell surface membrane proteins

    NASA Astrophysics Data System (ADS)

    Nishida, Noritaka; Osawa, Masanori; Takeuchi, Koh; Imai, Shunsuke; Stampoulis, Pavlos; Kofuku, Yutaka; Ueda, Takumi; Shimada, Ichio

    2014-04-01

    Cell surface receptors are integral membrane proteins that receive external stimuli, and transmit signals across plasma membranes. In the conventional view of receptor activation, ligand binding to the extracellular side of the receptor induces conformational changes, which convert the structure of the receptor into an active conformation. However, recent NMR studies of cell surface membrane proteins have revealed that their structures are more dynamic than previously envisioned, and they fluctuate between multiple conformations in an equilibrium on various timescales. In addition, NMR analyses, along with biochemical and cell biological experiments indicated that such dynamical properties are critical for the proper functions of the receptors. In this review, we will describe several NMR studies that revealed direct linkage between the structural dynamics and the functions of the cell surface membrane proteins, such as G-protein coupled receptors (GPCRs), ion channels, membrane transporters, and cell adhesion molecules.

  3. 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

  4. Surface Charge Visualization at Viable Living Cells.

    PubMed

    Perry, David; Paulose Nadappuram, Binoy; Momotenko, Dmitry; Voyias, Philip D; Page, Ashley; Tripathi, Gyanendra; Frenguelli, Bruno G; Unwin, Patrick R

    2016-03-01

    Scanning ion conductance microscopy (SICM) is demonstrated to be a powerful technique for quantitative nanoscale surface charge mapping of living cells. Utilizing a bias modulated (BM) scheme, in which the potential between a quasi-reference counter electrode (QRCE) in an electrolyte-filled nanopipette and a QRCE in bulk solution is modulated, it is shown that both the cell topography and the surface charge present at cellular interfaces can be measured simultaneously at high spatial resolution with dynamic potential measurements. Surface charge is elucidated by probing the properties of the diffuse double layer (DDL) at the cellular interface, and the technique is sensitive at both low-ionic strength and under typical physiological (high-ionic strength) conditions. The combination of experiments that incorporate pixel-level self-referencing (calibration) with a robust theoretical model allows for the analysis of local surface charge variations across cellular interfaces, as demonstrated on two important living systems. First, charge mapping at Zea mays root hairs shows that there is a high negative surface charge at the tip of the cell. Second, it is shown that there are distinct surface charge distributions across the surface of human adipocyte cells, whose role is the storage and regulation of lipids in mammalian systems. These are new features, not previously recognized, and their implications for the functioning of these cells are highlighted. PMID:26871001

  5. 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.

  6. Entry Kinetics and Cell-Cell Transmission of Surface-Bound Retroviral Vector Particles

    PubMed Central

    O’Neill, Lee S.; Skinner, Amy M.; Woodward, Josha A.; Kurre, Peter

    2010-01-01

    Background Transduction with recombinant Human Immunodeficiency Virus (HIV) -1 derived lentivirus vectors is a multi-step process initiated by surface attachment and subsequent receptor-directed uptake into the target cell. We previously reported the retention of vesicular stomatitis virus G protein (VSV-G) pseudotyped particles on murine progenitor cells and their delayed cell-cell transfer. Methods To examine the underlying mechanism in more detail we used a combination of approaches focused on investigating the role of receptor-independent factors in modulating attachment. Results Studies of synchronized transduction herein reveal cell-type specific rates of vector particle clearance with substantial delays during particle entry into murine hematopoietic progenitor cells. The observed uptake kinetics from the surface of the 1° cell correlate inversely with the magnitude of transfer to 2° targets, corresponding with our initial observation of preferential cell-cell transfer in the context of brief vector exposures. We further demonstrate that vector particle entry into cells is associated with the cell–type specific abundance of extracellular matrix fibronectin. Residual particle – ECM binding and 2° transfer can be competitively disrupted by heparin exposure without affecting murine progenitor homing and repopulation. Conclusions While cellular attachment factors, including fibronectin, aid gene transfer by colocalizing particles to cells and disfavoring early dissociation from targets, they also appear to stabilize particles on the cell surface. Our study highlights the inadvertent consequences for cell entry and cell-cell transfer. PMID:20440757

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Dendritic Cell Responses to Surface Properties of Clinical Titanium Surfaces

    PubMed Central

    Kou, Peng Meng; Schwartz, Zvi; Boyan, Barbara D.

    2010-01-01

    Dendritic cells (DCs) play pivotal roles in responding to foreign entities during an innate immune response and initiating effective adaptive immunity as well as maintaining immune tolerance. The sensitivity of DCs to foreign stimuli also makes them useful cells to assess the inflammatory response to biomaterials. Elucidating the material property-DC phenotype relationships using a well-defined biomaterial system is expected to provide criteria for immuno-modulatory biomaterial design. Clinical titanium (Ti) substrates, including pretreatment (PT), sand-blasted and acid-etched (SLA), and modified SLA (modSLA), with different roughness and surface energy were used to treat DCs and resulted in differential DC responses. PT and SLA induced a mature DC (mDC) phenotype, while modSLA promoted a non-inflammatory environment by supporting an immature DC (iDC) phenotype based on surface marker expression, cytokine production profiles and cell morphology. Principal component analysis (PCA) confirmed these experimental results, and it also indicated that the non-stimulating property of modSLA covaried with certain surface properties, such as high surface hydrophilicity, % oxygen and % Ti of the substrates. In addition to the previous research that demonstrated the superior osteogenic property of modSLA compared to PT and SLA, the result reported herein indicates that modSLA may further benefit implant osteo-integration by reducing local inflammation and its associated osteoclastogenesis. PMID:20977948

  18. 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

  19. 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. PMID:26372777

  20. 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

  1. 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®.

  2. Biomolecular strategies for cell surface engineering

    NASA Astrophysics Data System (ADS)

    Wilson, John Tanner

    Islet transplantation has emerged as a promising cell-based therapy for the treatment of diabetes, but its clinical efficacy remains limited by deleterious host responses that underlie islet destruction. In this dissertation, we describe the assembly of ultrathin conformal coatings that confer molecular-level control over the composition and biophysicochemical properties of the islet surface with implications for improving islet engraftment. Significantly, this work provides novel biomolecular strategies for cell surface engineering with broad biomedical and biotechnological applications in cell-based therapeutics and beyond. Encapsulation of cells and tissue offers a rational approach for attenuating deleterious host responses towards transplanted cells, but a need exists to develop cell encapsulation strategies that minimize transplant volume. Towards this end, we endeavored to generate nanothin films of diverse architecture with tunable properties on the extracellular surface of individual pancreatic islets through a process of layer-by-layer (LbL) self assembly. We first describe the formation of poly(ethylene glycol) (PEG)-rich conformal coatings on islets via LbL self assembly of poly(L-lysine)-g-PEG(biotin) and streptavidin. Multilayer thin films conformed to the geometrically and chemically heterogeneous islet surface, and could be assembled without loss of islet viability or function. Significantly, coated islets performed comparably to untreated controls in a murine model of allogenic intraportal islet transplantation, and, to our knowledge, this is the first study to report in vivo survival and function of nanoencapsulated cells or cell aggregates. Based on these findings, we next postulated that structurally similar PLL-g-PEG copolymers comprised of shorter PEG grafts might be used to initiate and propagate the assembly of polyelectrolyte multilayer (PEM) films on pancreatic islets, while simultaneously preserving islet viability. Through control of PLL

  3. 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

  4. 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

  5. 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.

  6. Surface Physicochemistry and Ionic Strength Affects eDNA’s Role in Bacterial Adhesion to Abiotic Surfaces

    PubMed Central

    Regina, Viduthalai R.; Lokanathan, Arcot R.; Modrzyński, Jakub J.; Sutherland, Duncan S.; Meyer, Rikke L.

    2014-01-01

    Extracellular DNA (eDNA) is an important structural component of biofilms formed by many bacteria, but few reports have focused on its role in initial cell adhesion. The aim of this study was to investigate the role of eDNA in bacterial adhesion to abiotic surfaces, and determine to which extent eDNA-mediated adhesion depends on the physicochemical properties of the surface and surrounding liquid. We investigated eDNA alteration of cell surface hydrophobicity and zeta potential, and subsequently quantified the effect of eDNA on the adhesion of Staphylococcus xylosus to glass surfaces functionalised with different chemistries resulting in variable hydrophobicity and charge. Cell adhesion experiments were carried out at three different ionic strengths. Removal of eDNA from S. xylosus cells by DNase treatment did not alter the zeta potential, but rendered the cells more hydrophilic. DNase treatment impaired adhesion of cells to glass surfaces, but the adhesive properties of S. xylosus were regained within 30 minutes if DNase was not continuously present, implying a continuous release of eDNA in the culture. Removal of eDNA lowered the adhesion of S. xylosus to all surfaces chemistries tested, but not at all ionic strengths. No effect was seen on glass surfaces and carboxyl-functionalised surfaces at high ionic strength, and a reverse effect occurred on amine-functionalised surfaces at low ionic strength. However, eDNA promoted adhesion of cells to hydrophobic surfaces irrespective of the ionic strength. The adhesive properties of eDNA in mediating initial adhesion of S. xylosus is thus highly versatile, but also dependent on the physicochemical properties of the surface and ionic strength of the surrounding medium. PMID:25122477

  7. Melanopsin, Photosensitive Ganglion Cells, and Seasonal Affective Disorder

    PubMed Central

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

    2013-01-01

    ROECKLEIN, K.A., WONG, P.M., MILLER, M.A., DONOFRY, S.D., KAMARCK, M.L., BRAINARD, G.C. Melanopsin, Photosensitive Ganglion Cells, and Seasonal Affective Disorder…NEUROSCI BIOBEHAV REV x(x) XXX-XXX, 2012. 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. PMID:23286902

  8. 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

  9. 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

  10. Glycopeptide Capture for Cell Surface Proteomics

    PubMed Central

    Lee, M. C. Gilbert; Sun, Bingyun

    2014-01-01

    Cell surface proteins, including extracellular matrix proteins, participate in all major cellular processes and functions, such as growth, differentiation, and proliferation. A comprehensive characterization of these proteins provides rich information for biomarker discovery, cell-type identification, and drug-target selection, as well as helping to advance our understanding of cellular biology and physiology. Surface proteins, however, pose significant analytical challenges, because of their inherently low abundance, high hydrophobicity, and heavy post-translational modifications. Taking advantage of the prevalent glycosylation on surface proteins, we introduce here a high-throughput glycopeptide-capture approach that integrates the advantages of several existing N-glycoproteomics means. Our method can enrich the glycopeptides derived from surface proteins and remove their glycans for facile proteomics using LC-MS. The resolved N-glycoproteome comprises the information of protein identity and quantity as well as their sites of glycosylation. This method has been applied to a series of studies in areas including cancer, stem cells, and drug toxicity. The limitation of the method lies in the low abundance of surface membrane proteins, such that a relatively large quantity of samples is required for this analysis compared to studies centered on cytosolic proteins. PMID:24836557

  11. 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

  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. PMID:26977382

  13. Curcumin affects cell survival and cell volume regulation in human renal and intestinal cells

    PubMed Central

    Kössler, Sonja; Nofziger, Charity; Jakab, Martin; Dossena, Silvia; Paulmichl, Markus

    2012-01-01

    Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1E,6E-heptadiene-3,5-dione or diferuloyl methane) is a polyphenol derived from the Curcuma longa plant, commonly known as turmeric. This substance has been used extensively in Ayurvedic medicine for centuries for its anti-oxidant, analgesic, anti-inflammatory and antiseptic activity. More recently curcumin has been found to possess anti-cancer properties linked to its pro-apoptotic and anti-proliferative actions. The underlying mechanisms of these diverse effects are complex, not fully elucidated and subject of intense scientific debate. Despite increasing evidence indicating that different cation channels can be a molecular target for curcumin, very little is known about the effect of curcumin on chloride channels. Since, (i) the molecular structure of curcumin indicates that the substance could potentially interact with chloride channels, (ii) chloride channels play a role during the apoptotic process and regulation of the cell volume, and (iii) apoptosis is a well known effect of curcumin, we set out to investigate whether or not curcumin could (i) exert a modulatory effect (direct or indirect) on the swelling activated chloride current IClswell in a human cell system, therefore (ii) affect cell volume regulation and (iii) ultimately modulate cell survival. The IClswell channels, which are essential for regulating the cell volume after swelling, are also known to be activated under isotonic conditions as an early event in the apoptotic process. Here we show that long-term exposure of a human kidney cell line to extracellular 0.1–10 μM curcumin modulates IClswell in a dose-dependent manner (0.1 μM curcumin is ineffective, 0.5–5.0 μM curcumin increase, while 10 μM curcumin decrease the current), and short-term exposure to micromolar concentrations of curcumin does not affect IClswell neither if applied from the extracellular nor from the intracellular side – therefore, a direct effect of curcumin on

  14. 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.

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

    PubMed

    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 given gene

  17. Increase of cardiolipin content in Staphylococcus aureus by the use of antibiotics affecting the cell wall.

    PubMed

    Kariyama, R

    1982-12-01

    Effect of antibiotics affecting cell wall synthesis on phospholipid composition in Staphylococcus aureus 209P was examined. Each antibiotic was added in the middle exponential growth phase and the growth was followed turbidimetrically. Penicillin, fosfomycin, cycloserine, moenomycin and cefazolin caused a leveling off of turbidity and growth to cease without lysis. Enramycin and bacitracin were bacteriolytic. Bacteriolytic antibiotics caused a greater increase of cardiolipin content than those that were non-bacteriolytic. The amount of phosphatidylglycerol decreased in proportion to the increment of cardiolipin content. Since bacteriolytic antibiotics bind to undecaprenol, the role of cardiolipin was discussed in relation to the mechanism of synthesis of cell surface materials. PMID:7166534

  18. 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.

  19. Specificity of human galectins on cell surfaces.

    PubMed

    Rapoport, E M; Bovin, N V

    2015-07-01

    Galectins are β-galactoside-binding proteins sharing homology in amino acid sequence of their carbohydrate-recognition domain. Their carbohydrate specificity outside cells has been studied previously. The main conclusion of these studies was that several levels of glycan ligand recognition exist for galectins: (i) disaccharide Galβ1-4GlcNAc (LN, N-acetyllactosamine) binds stronger than β-galactopyranose; (ii) substitution at O-2 and O-3 of galactose residue as well as core fragments ("right" from GlcNAc) provides significant increase in affinity; (iii) similarly glycosylated proteins can differ significantly in affinity to galectins. Information about the natural cellular receptors of galectins is limited. Until recently, it was impossible to study specificity of cell-bound galectins. A model based on controlled incorporation of a single protein into glycocalyx of cells and subsequent interaction of loaded cells with synthetic glycoprobes measured by flow cytometry made this possible recently. In this review, data about glycan specificity of proto-, chimera-, and tandem-repeat type galectins on the cell surface are systematized, and comparative analysis of the results with data on specificity of galectins in artificial systems was performed. The following conclusions from these studies were made: (i) cellular galectins have practically no ability to bind disaccharide LNn, but display affinity to 3'-substituted oligolactosamines and oligomers LNn; (ii) tandem-repeat type galectins recognize another disaccharide, namely Galβ1-3GlcNAc (Le(c)); (iii) on the cell surface, tandem-repeat type galectins conserve the ability to display high affinity to blood group antigens of ABH system; (iv) in general, when galectins are immersed into glycocalyx, they are more selective regarding glycan interactions. Thus, we conclude that competitive interaction of galectins with cell microenvironment (endogenous cell glycans) is the main factor providing selectivity of galectins in

  20. Plant-derived decapeptide OSIP108 interferes with Candida albicans biofilm formation without affecting cell viability.

    PubMed

    Delattin, Nicolas; De Brucker, Katrijn; Craik, David J; Cheneval, Olivier; Fröhlich, Mirjam; Veber, Matija; Girandon, Lenart; Davis, Talya R; Weeks, Anne E; Kumamoto, Carol A; Cos, Paul; Coenye, Tom; De Coninck, Barbara; Cammue, Bruno P A; Thevissen, Karin

    2014-05-01

    We previously identified a decapeptide from the model plant Arabidopsis thaliana, OSIP108, which is induced upon fungal pathogen infection. In this study, we demonstrated that OSIP108 interferes with biofilm formation of the fungal pathogen Candida albicans without affecting the viability or growth of C. albicans cells. OSIP108 displayed no cytotoxicity against various human cell lines. Furthermore, OSIP108 enhanced the activity of the antifungal agents amphotericin B and caspofungin in vitro and in vivo in a Caenorhabditis elegans-C. albicans biofilm infection model. These data point to the potential use of OSIP108 in combination therapy with conventional antifungal agents. In a first attempt to unravel its mode of action, we screened a library of 137 homozygous C. albicans mutants, affected in genes encoding cell wall proteins or transcription factors important for biofilm formation, for altered OSIP108 sensitivity. We identified 9 OSIP108-tolerant C. albicans mutants that were defective in either components important for cell wall integrity or the yeast-to-hypha transition. In line with these findings, we demonstrated that OSIP108 activates the C. albicans cell wall integrity pathway and that its antibiofilm activity can be blocked by compounds inhibiting the yeast-to-hypha transition. Furthermore, we found that OSIP108 is predominantly localized at the C. albicans cell surface. These data point to interference of OSIP108 with cell wall-related processes of C. albicans, resulting in impaired biofilm formation. PMID:24566179

  1. Cell Surface Markers in HTLV-1 Pathogenesis

    PubMed Central

    Kress, Andrea K.; Grassmann, Ralph; Fleckenstein, Bernhard

    2011-01-01

    The phenotype of HTLV-1-transformed CD4+ T lymphocytes largely depends on defined viral effector molecules such as the viral oncoprotein Tax. In this review, we exemplify the expression pattern of characteristic lineage markers, costimulatory receptors and ligands of the tumor necrosis factor superfamily, cytokine receptors, and adhesion molecules on HTLV-1-transformed cells. These molecules may provide survival signals for the transformed cells. Expression of characteristic surface markers might therefore contribute to persistence of HTLV-1-transformed lymphocytes and to the development of HTLV-1-associated disease. PMID:21994790

  2. Cell Wall Mannan and Cell Surface Hydrophobicity in Candida albicans Serotype A and B Strains

    PubMed Central

    Masuoka, James; Hazen, Kevin C.

    2004-01-01

    Cell surface hydrophobicity contributes to the pathogenesis of the opportunistic fungal pathogen Candida albicans. Previous work demonstrated a correlation between hydrophobicity status and changes in the acid-labile, phosphodiester-linked β-1,2-oligomannoside components of the N-linked glycans of cell wall mannoprotein. Glycan composition also defines the two major serotypes, A and B, of C. albicans strains. Here, we show that the cell surface hydrophobicity of the two serotypes is qualitatively different, suggesting that the serotypes may differ in how they modulate cell surface hydrophobicity status. The cell wall mannoproteins from hydrophilic and hydrophobic cells of both serotypes were compared to determine whether the glycan differences due to serotype affect the glycan differences due to hydrophobicity status. Composition analysis showed that the protein, hexose, and phosphate contents of the mannoprotein fraction did not differ significantly among the strains tested. Electrophoretic profiles of the acid-labile mannan differed only with hydrophobicity status, not serotype, though some strain-specific differences were observed. Furthermore, a newly available β-1,2-oligomannoside ladder allowed unambiguous identification of acid-labile mannan components. Finally, to assess whether the acid-stable mannan also affects cell surface hydrophobicity status, this fraction was fragmented into its component branches by acetolysis. The electrophoretic profiles of the acid-stable branches were very similar regardless of hydrophobicity status. However, differences were observed between serotypes. These results support and extend our current model that modification of the acid-labile β-1,2-oligomannoside chain length but not modification of the acid-stable region is one common mechanism by which switching of cell surface hydrophobicity status of C. albicans strains occurs. PMID:15501748

  3. 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

  4. Self-assembled monolayers of alkanethiolates on surface chemistry groups in osteosarcoma cells

    PubMed Central

    DENG, YING-HU; LI, LI-HUA; HE, JIN; LI, MEI; ZHANG, YU; WANG, XIU-MEI; CUI, FU-ZHAI; XIA, HONG

    2015-01-01

    Cell biomedical behavior is influenced by a number of factors, and the extracellular matrix (ECM) of the cellular microenvironment affects certain cancer cells. In the current study, U-2OS cells were cultured on gold surfaces modified with different terminal chemical groups [methyl (-CH3), amino (-NH2), hydroxyl (-OH) and carboxyl (-COOH)]. The results revealed that different chemical surfaces convey different behaviors. The density of the different functional surfaces was confirmed by atomic force microscopy. Cell morphology, proliferation rate and cell cycle were investigated using scanning electron microscopy, cell counting and flow cytometry. In conclusion, the type of chemical group on a biomaterial is an important property for the growth of osteosarcoma cells; -NH2 and -COOH surfaces sustained visible cell adhesion and promoted cell growth. PMID:25373556

  5. 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. PMID:27098435

  6. 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.

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

    PubMed

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

    2016-04-29

    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. PMID:26984937

  8. 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. PMID:26952425

  9. 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...

  10. 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

  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. The algal metabolite yessotoxin affects heterogeneous nuclear ribonucleoproteins in HepG2 cells.

    PubMed

    Young, Clifford; Truman, Penelope; Boucher, Magalie; Keyzers, Robert A; Northcote, Peter; Jordan, T William

    2009-05-01

    The dinoflagellate metabolite yessotoxin (YTX) is produced by several species of algae and accumulates in marine food chains, leading to concerns about possible affects on aquaculture industries and human health. In mice used for toxicity testing, YTX is lethal by the intraperitoneal route, but is considerably less toxic when orally administered. The mode of action of YTX and its potential effect on humans is unclear and we therefore conducted the first proteomic analysis of the effects of this compound. We used 2-DE to examine protein changes in HepG2 cell cultures exposed to 1.4 microM YTX for 3, 12.5, 18 and 24 h. After selecting proteins that changed more than three-fold after YTX exposure, 55 spots were deemed significantly affected by the toxin (p<0.05). Major groups of affected proteins include members from the heterogeneous nuclear ribonucleoprotein (hnRNP), lamin, cathepsin and heat shock protein families that often are associated with apoptosis. We therefore confirmed apoptosis using Annexin-V-FLUOS staining of phosphatidylserine exposed at the surface of apoptotic cells. Ingenuity pathways analysis also indicated effects on pathways involved in protein processing, cell cycling and cell death. PMID:19343718

  13. 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

  14. Yeast cell-surface expression of chitosanase from Paenibacillus fukuinensis.

    PubMed

    Fukuda, Takeshi; Isogawa, Danya; Takagi, Madoka; Kato-Murai, Michiko; Kimoto, Hisashi; Kusaoke, Hideo; Ueda, Mitsuyoshi; Suye, Shin-Ichiro

    2007-11-01

    To produce chitoorigosaccharides using chitosan, we attempted to construct Paenibacillus fukuinensis chitosanase-displaying yeast cells as a whole-cell biocatalyst through yeast cell-surface engineering. The localization of the chitosanase on the yeast cell surface was confirmed by immunofluorescence labeling of cells. The chitosanase activity of the constructed yeast was investigated by halo assay and the dinitrosalicylic acid method. PMID:17986777

  15. 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.

  16. 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.

  17. 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

  18. 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. PMID:23852884

  19. Scrapie affects the maturation cycle and immune complex trapping by follicular dendritic cells in mice.

    PubMed

    McGovern, Gillian; Mabbott, Neil; Jeffrey, Martin

    2009-01-01

    Transmissible spongiform encephalopathies (TSEs) or prion diseases are infectious neurological disorders of man and animals, characterised by abnormal disease-associated prion protein (PrP(d)) accumulations in the brain and lymphoreticular system (LRS). Prior to neuroinvasion, TSE agents often accumulate to high levels within the LRS, apparently without affecting immune function. However, our analysis of scrapie-affected sheep shows that PrP(d) accumulations within the LRS are associated with morphological changes to follicular dendritic cells (FDCs) and tingible body macrophages (TBMs). Here we examined FDCs and TBMs in the mesenteric lymph nodes (MLNs) of scrapie-affected mice by light and electron microscopy. In MLNs from uninfected mice, FDCs could be morphologically categorised into immature, mature and regressing forms. However, in scrapie-affected MLNs this maturation cycle was adversely affected. FDCs characteristically trap and retain immune complexes on their surfaces, which they display to B-lymphocytes. In scrapie-affected MLNs, some FDCs were found where areas of normal and abnormal immune complex retention occurred side by side. The latter co-localised with PrP(d) plasmalemmal accumulations. Our data suggest this previously unrecognised morphology represents the initial stage of an abnormal FDC maturation cycle. Alterations to the FDCs included PrP(d) accumulation, abnormal cell membrane ubiquitin and excess immunoglobulin accumulation. Regressing FDCs, in contrast, appeared to lose their membrane-attached PrP(d). Together, these data suggest that TSE infection adversely affects the maturation and regression cycle of FDCs, and that PrP(d) accumulation is causally linked to the abnormal pathology observed. We therefore support the hypothesis that TSEs cause an abnormality in immune function. PMID:19997557

  20. 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

  1. 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. PMID:26852101

  2. Global Transcriptomic Analysis of Model Human Cell Lines Exposed to Surface-Modified Gold Nanoparticles: The Effect of Surface Chemistry

    PubMed Central

    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. PMID:25491924

  3. 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.

  4. 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.

  5. Culture conditions affect the cholinergic development of an isolated subpopulation of chick mesencephalic neural crest cells.

    PubMed

    Barald, K F

    1989-10-01

    Although neural crest cells are known to be very responsive to environmental cues during their development, recent evidence indicates that at least some subpopulations may be committed to a specific differentiation program prior to migration. Because the neural crest is composed of a heterogeneous mixture of cells that contributes to many vertebrate cell lineages, assessing the properties of specific subpopulations and the effect of the environment on their development has been difficult. To address this problem, we have isolated a pure subpopulation of chick mesencephalic neural crest cells by fluorescence no-flow cytometry after labeling them with monoclonal antibodies (Mabs) to a 75-kDa cell surface antigen that is associated with high affinity choline uptake. When cultures of chick mesencephalic neural crest cells are labeled with these Mabs and a fluorescent second step antibody, approximately 5% of the cells are antigen-positive (A+). After sorting, 100% of the resulting cultured mesencephalic neural crest cells are A+. The Mabs we used also label all of the neurons of the embryonic chick and quail ciliary ganglion in vivo and in vitro. We have compared the effect of various cell culture media on the isolated neural crest subpopulation and the heterogeneous chick mesencephalic neural crest from which it was derived. A+ cells were passaged and grown in a variety of media, each of which differently affected its characteristics and development. A+ cells proliferated in the presence of 15% fetal bovine serum (FBS) and high concentrations (10-15%) of chick embryo extract, but did not differentiate, although they retained basal levels of choline acetyltransferase (ChAT) activity. However, in chick serum and high (25 mM as opposed to 7 mM) K+, and heart-, iris-, or lung-conditioned medium, all of which are known to promote survival and/or cholinergic development of ciliary ganglion neurons, the cells ceased to proliferate and all of the cells in the culture became

  6. 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. PMID:26693600

  7. 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

  8. Towards understanding how surface life can affect interior geological processes: a non-equilibrium thermodynamics approach

    NASA Astrophysics Data System (ADS)

    Dyke, J. G.; Gans, F.; Kleidon, A.

    2011-06-01

    Life has significantly altered the Earth's atmosphere, oceans and crust. To what extent has it also affected interior geological processes? To address this question, three models of geological processes are formulated: mantle convection, continental crust uplift and erosion and oceanic crust recycling. These processes are characterised as non-equilibrium thermodynamic systems. Their states of disequilibrium are maintained by the power generated from the dissipation of energy from the interior of the Earth. Altering the thickness of continental crust via weathering and erosion affects the upper mantle temperature which leads to changes in rates of oceanic crust recycling and consequently rates of outgassing of carbon dioxide into the atmosphere. Estimates for the power generated by various elements in the Earth system are shown. This includes, inter alia, surface life generation of 264 TW of power, much greater than those of geological processes such as mantle convection at 12 TW. This high power results from life's ability to harvest energy directly from the sun. Life need only utilise a small fraction of the generated free chemical energy for geochemical transformations at the surface, such as affecting rates of weathering and erosion of continental rocks, in order to affect interior, geological processes. Consequently when assessing the effects of life on Earth, and potentially any planet with a significant biosphere, dynamical models may be required that better capture the coupled nature of biologically-mediated surface and interior processes.

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. Human Immunodeficiency Syndromes Affecting Human Natural Killer Cell Cytolytic Activity

    PubMed Central

    Ham, Hyoungjun; Billadeau, Daniel D.

    2013-01-01

    Natural killer (NK) cells are lymphocytes of the innate immune system that secrete cytokines upon activation and mediate the killing of tumor cells and virus-infected cells, especially those that escape the adaptive T cell response caused by the down regulation of MHC-I. The induction of cytotoxicity requires that NK cells contact target cells through adhesion receptors, and initiate activation signaling leading to increased adhesion and accumulation of F-actin at the NK cell cytotoxic synapse. Concurrently, lytic granules undergo minus-end directed movement and accumulate at the microtubule-organizing center through the interaction with microtubule motor proteins, followed by polarization of the lethal cargo toward the target cell. Ultimately, myosin-dependent movement of the lytic granules toward the NK cell plasma membrane through F-actin channels, along with soluble N-ethylmaleimide-sensitive factor attachment protein receptor-dependent fusion, promotes the release of the lytic granule contents into the cleft between the NK cell and target cell resulting in target cell killing. Herein, we will discuss several disease-causing mutations in primary immunodeficiency syndromes and how they impact NK cell-mediated killing by disrupting distinct steps of this tightly regulated process. PMID:24478771

  15. Surface shape affects the three-dimensional exploratory movements of nocturnal arboreal snakes.

    PubMed

    Jayne, Bruce C; Olberding, Jeffrey P; Athreya, Dilip; Riley, Michael A

    2012-12-01

    Movement and searching behaviors at diverse spatial scales are important for understanding how animals interact with their environment. Although the shapes of branches and the voids in arboreal habitats seem likely to affect searching behaviors, their influence is poorly understood. To gain insights into how both environmental structure and the attributes of an animal may affect movement and searching, we compared the three-dimensional exploratory movements of snakes in the dark on two simulated arboreal surfaces (disc and horizontal cylinder). Most of the exploratory movements of snakes in the dark were a small fraction of the distances they could reach while bridging gaps in the light. The snakes extended farther away from the edge of the supporting surface at the ends of the cylinder than from the sides of the cylinder or from any direction from the surface of the disc. The exploratory movements were not random, and the surface shape and three-dimensional directions had significant interactive effects on how the movements were structured in time. Thus, the physical capacity for reaching did not limit the area that was explored, but the shape of the supporting surface and the orientation relative to gravity did create biased searching patterns. PMID:23052853

  16. 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. PMID:23625878

  17. Autologous Stem Cell Therapy: How Aging and Chronic Diseases Affect Stem and Progenitor Cells

    PubMed Central

    Efimenko, Anastasia Yu.; Kochegura, Tatiana N.; Akopyan, Zhanna A.; Parfyonova, Yelena V.

    2015-01-01

    Abstract During recent years different types of adult stem/progenitor cells have been successfully applied for the treatment of many pathologies, including cardiovascular diseases. The regenerative potential of these cells is considered to be due to their high proliferation and differentiation capacities, paracrine activity, and immunologic privilege. However, therapeutic efficacy of the autologous stem/progenitor cells for most clinical applications remains modest, possibly because of the attenuation of their regenerative potential in aged patients with chronic diseases such as cardiovascular diseases and metabolic disorders. In this review we will discuss the risk factors affecting the therapeutic potential of adult stem/progenitor cells as well as the main approaches to mitigating them using the methods of regenerative medicine. PMID:26309780

  18. The Azospirillum brasilense Che1 Chemotaxis Pathway Controls Swimming Velocity, Which Affects Transient Cell-to-Cell Clumping

    PubMed Central

    Bible, Amber; Russell, Matthew H.

    2012-01-01

    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. PMID:22522896

  19. 5-ASA Affects Cell Cycle Progression in Colorectal Cells by Reversibly Activating a Replication Checkpoint

    PubMed Central

    LUCIANI, M. GLORIA; CAMPREGHER, CHRISTOPH; FORTUNE, JOHN M.; KUNKEL, THOMAS A.; GASCHE, CHRISTOPH

    2007-01-01

    Background & Aims Individuals with inflammatory bowel disease are at risk of developing colorectal cancer (CRC). Epidemiologic, animal, and laboratory studies suggest that 5-amino-salicylic acid (5-ASA) protects from the development of CRC by altering cell cycle progression and by inducing apoptosis. Our previous results indicate that 5-ASA improves replication fidelity in colorectal cells, an effect that is active in reducing mutations. In this study, we hypothesized that 5-ASA restrains cell cycle progression by activating checkpoint pathways in colorectal cell lines, which would prevent tumor development and improve genomic stability. Methods CRC cells with different genetic backgrounds such as HT29, HCT116, HCT116p53−/−, HCT116+chr3, and LoVo were treated with 5-ASA for 2–96 hours. Cell cycle progression, phosphorylation, and DNA binding of cell cycle checkpoint proteins were analyzed. Results We found that 5-ASA at concentrations between 10 and 40 mmol/L affects cell cycle progression by inducing cells to accumulate in the S phase. This effect was independent of the hMLH1, hMSH2, and p53 status because it was observed to a similar extent in all cell lines under investigation. Moreover, wash-out experiments demonstrated reversibility within 48 hours. Although p53 did not have a causative role, p53 Ser15 was strongly phosphorylated. Proteins involved in the ATM-and-Rad3-related kinase (ATR)-dependent S-phase checkpoint response (Chk1 and Rad17) were also phosphorylated but not ataxia telengectasia mutated kinase. Conclusions Our data demonstrate that 5-ASA causes cells to reversibly accumulate in S phase and activate an ATR-dependent checkpoint. The activation of replication checkpoint may slow down DNA replication and improve DNA replication fidelity, which increases the maintenance of genomic stability and counteracts carcinogenesis. PMID:17241873

  20. Cell interactions with laser-modified polymer surfaces.

    PubMed

    Ball, M D; Sherlock, R; Glynn, T

    2004-04-01

    The performance of a polymeric biomaterial depends on the bulk and surface properties. Often, however, the suitability of the surface properties is compromised in favour of the bulk properties. Altering the surface properties of these materials will have a profound effect on how cells and proteins interact with them. Here, we have used an excimer laser to modify the surface wettability of nylon 12. The surface treatment is rapid, cost-effective and can cause reproducible changes in the surface structure of the polymers. Polymers were treated with short wavelength ( < 200 nm) UV light. These wavelengths have sufficient photon energy (6.4eV) to cause bond scission at the material surface. This results in a surface reorganisation with incorporation of oxygen. Surface wettability changes were confirmed using contact angle measurements. Cell interactions with the surfaces were examined using 3T3 fibroblast and HUVEC cells. Cells morphology was examined using a confocal laser scanning microscope (CLSM). Cell activity and cell number on the treated nylon were assessed using biochemical assays for up to seven days. Both fibroblasts and endothelial cells initially proliferated better on treated compared with untreated samples. However, over seven days activity decreased for both cell types on the control samples and endothelial cell activity and cell number also decreased on the treated polymer. PMID:15332615

  1. 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...

  2. 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

  3. LRP-1–CD44, a New Cell Surface Complex Regulating Tumor Cell Adhesion

    PubMed Central

    Perrot, Gwenn; Langlois, Benoit; Devy, Jérôme; Jeanne, Albin; Verzeaux, Laurie; Almagro, Sébastien; Sartelet, Hervé; Hachet, Cathy; Schneider, Christophe; Sick, Emilie; David, Marion; Khrestchatisky, Michel; Emonard, Hervé; Martiny, Laurent

    2012-01-01

    The low-density lipoprotein receptor-related protein 1 (LRP-1) is a large endocytic receptor mediating the clearance of various molecules from the extracellular matrix. In the field of cancer, LRP-1-mediated endocytosis was first associated with antitumor properties. However, recent results suggested that LRP-1 may coordinate the adhesion-deadhesion balance in malignant cells to support tumor progression. Here, we observed that LRP-1 silencing or RAP (receptor-associated protein) treatment led to accumulation of CD44 at the tumor cell surface. Moreover, we evidenced a tight interaction between CD44 and LRP-1, not exclusively localized in lipid rafts. Overexpression of LRP-1-derived minireceptors indicated that the fourth ligand-binding cluster of LRP-1 is required to bind CD44. Labeling of CD44 with EEA1 and LAMP-1 showed that internalized CD44 is routed through early endosomes toward lysosomes in a LRP-1-dependent pathway. LRP-1-mediated internalization of CD44 was highly reduced under hyperosmotic conditions but poorly affected by membrane cholesterol depletion, revealing that it proceeds mostly via clathrin-coated pits. Finally, we demonstrated that CD44 silencing abolishes RAP-induced tumor cell attachment, revealing that cell surface accumulation of CD44 under LRP-1 blockade is mainly responsible for the stimulation of tumor cell adhesion. Altogether, our data shed light on the LRP-1-mediated internalization of CD44 that appeared critical to define the adhesive properties of tumor cells. PMID:22711991

  4. Basic surface properties of mononuclear cells from Didelphis marsupialis.

    PubMed

    Nacife, V P; de Meirelles, M de N; Silva Filho, F C

    1998-01-01

    The electrostatic surface charge and surface tension of mononuclear cells/monocytes obtained from young and adult marsupials (Didelphis marsupialis) were investigated by using cationized ferritin and colloidal iron hydroxyde, whole cell electrophoresis, and measurements of contact angles. Anionic sites were found distributed throughout the entire investigated cell surfaces. The results revealed that the anionic character of the cells is given by electrostatic charges corresponding to -18.8 mV (cells from young animals) and -29.3 mV (cells from adult animals). The surface electrostatic charge decreased from 10 to 65.2% after treatment of the cells with each one of trypsin, neuraminidase and phospholipase C. The hydrophobic nature of the mononuclear cell surfaces studied by using the contact angle method revealed that both young and adult cells possess cell surfaces of high hidrofilicity since the angles formed with drops of saline water were 42.5 degrees and 40.8 degrees, respectively. Treatment of the cells with trypsin or neuraminidase rendered their surfaces more hydrophobic, suggesting that sialic acid-containing glycoproteins are responsible for most of the hydrophilicity observed in the mononuclear cell surfaces from D. marsupialis. PMID:9921307

  5. 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

  6. 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

  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. PMID:26498911

  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. Surface cell differentiation controls tissue surface tension and tissue positioning during zebrafish gastrulation

    NASA Astrophysics Data System (ADS)

    Krens, S. F. G.

    2011-03-01

    Differences in tissue surface tension (TST) between different tissue types are thought to guide tissue organization and cell sorting in development. Measurements of TST have been useful to predict the outcome of in vitro cell sorting and envelopment experiments. However, the outcome of cell sorting experiments in vitro often substantially differs from tissue positioning in vivo, raising questions as to the actual contribution of TST to tissue positioning within the developing embryo. Here, we show that surface tension of germ layer tissues during zebrafish gastrulation critically relies on the differentiation of their surface cells. We also show that surface differentiation of the different germ layer tissues varies and is considerably different between the situation in vitro and in vivo, explaining the apparent dissimilar outcome of cell segregation between these two situations. To analyze germ layer TST as a function of surface cell differentiation, we interfere with surface cell properties of germ layer aggregates by misexpressing genes involved in surface cell differentiation specifically within surface cells using the GAL4-UAS system, and measure tissue surface tension using both parallel plate compression and micropipette aspiration techniques. Our data provides evidence in favor of a critical function of surface cell differentiation in modulating TST and subsequently tissue positioning within the developing embryo.

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

    PubMed

    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. PMID:24720912

  14. Bax alpha perturbs T cell development and affects cell cycle entry of T cells.

    PubMed Central

    Brady, H J; Gil-Gómez, G; Kirberg, J; Berns, A J

    1996-01-01

    Bax alpha can heterodimerize with Bcl-2 and Bcl-X(L), countering their effects, as well as promoting apoptosis on overexpression. We show that bax alpha transgenic mice have greatly reduced numbers of mature T cells, which results from an impaired positive selection in the thymus. This perturbation in positive selection is accompanied by an increase in the number of cycling thymocytes. Further to this, mature T cells overexpressing Bax alpha have lower levels of p27Kip1 and enter S phase more rapidly in response to interleukin-2 stimulation than do control T cells, while the converse is true of bcl-2 transgenic T cells. These data indicate that apoptotic regulatory proteins can modulate the level of cell cycle-controlling proteins and thereby directly impact on the cell cycle. Images PMID:9003775

  15. 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

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

    PubMed Central

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

    2015-01-01

    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. PMID:26056301

  17. Ionizing Radiation Impairs T Cell Activation by Affecting Metabolic Reprogramming

    PubMed Central

    Li, Heng-Hong; Wang, Yi-wen; Chen, Renxiang; Zhou, Bin; Ashwell, Jonathan D.; Fornace, Albert J.

    2015-01-01

    Ionizing radiation has a variety of acute and long-lasting adverse effects on the immune system. Whereas measureable effects of radiation on immune cell cytotoxicity and population change have been well studied in human and animal models, little is known about the functional alterations of the surviving immune cells after ionizing radiation. The objective of this study was to delineate the effects of radiation on T cell function by studying the alterations of T cell receptor activation and metabolic changes in activated T cells isolated from previously irradiated animals. Using a global metabolomics profiling approach, for the first time we demonstrate that ionizing radiation impairs metabolic reprogramming of T cell activation, which leads to substantial decreases in the efficiency of key metabolic processes required for activation, such as glucose uptake, glycolysis, and energy metabolism. In-depth understanding of how radiation impacts T cell function highlighting modulation of metabolism during activation is not only a novel approach to investigate the pivotal processes in the shift of T cell homeostasis after radiation, it also may lead to new targets for therapeutic manipulation in the combination of radiotherapy and immune therapy. Given that appreciable effects were observed with as low as 10 cGy, our results also have implications for low dose environmental exposures. PMID:26078715

  18. 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

  19. 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

  20. 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).

  1. Engineered antifouling microtopographies: surface pattern effects on cell distribution.

    PubMed

    Decker, Joseph T; Sheats, Julian T; Brennan, Anthony B

    2014-12-23

    Microtopography has been observed to lead to altered attachment behavior for marine fouling organisms; however, quantification of this phenomenon is lacking in the scientific literature. Here, we present quantitative measurement of the disruption of normal attachment behavior of the fouling algae Ulva linza by antifouling microtopographies. The distribution of the diatom Navicula incerta was shown to be unaffected by the presence of topography. The radial distribution function was calculated for both individual zoospores and cells as well as aggregates of zoospores from attachment data for a variety topographic configurations and at a number of different attachment densities. Additionally, the screening distance and maximum values were mapped according to the location of zoospore aggregates within a single unit cell. We found that engineered topographies decreased the distance between spore aggregates compared to that for a smooth control surface; however, the distributions for individual spores were unchanged. We also found that the local attachment site geometry affected the screening distance for aggregates of zoospores, with certain geometries decreasing screening distance and others having no measurable effect. The distribution mapping techniques developed and explored in this article have yielded important insight into the design parameters for antifouling microtopographies that can be implemented in the next generation of antifouling surfaces. PMID:25420235

  2. Cell Surface Markers in Colorectal Cancer Prognosis

    PubMed Central

    Belov, Larissa; Zhou, Jerry; Christopherson, Richard I.

    2011-01-01

    The classification of colorectal cancers (CRC) is currently based largely on histologically determined tumour characteristics, such as differentiation status and tumour stage, i.e., depth of tumour invasion, involvement of regional lymph nodes and the occurrence of metastatic spread to other organs. These are the conventional prognostic factors for patient survival and often determine the requirement for adjuvant therapy after surgical resection of the primary tumour. However, patients with the same CRC stage can have very different disease-related outcomes. For some, surgical removal of early-stage tumours leads to full recovery, while for others, disease recurrence and metastasis may occur regardless of adjuvant therapy. It is therefore important to understand the molecular processes that lead to disease progression and metastasis and to find more reliable prognostic markers and novel targets for therapy. This review focuses on cell surface proteins that correlate with tumour progression, metastasis and patient outcome, and discusses some of the challenges in finding prognostic protein markers in CRC. PMID:21339979

  3. 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

  4. Calreticulin: Roles in Cell-Surface Protein Expression

    PubMed Central

    Jiang, Yue; Dey, Sandeepa; Matsunami, Hiroaki

    2014-01-01

    In order to perform their designated functions, proteins require precise subcellular localizations. For cell-surface proteins, such as receptors and channels, they are able to transduce signals only when properly targeted to the cell membrane. Calreticulin is a multi-functional chaperone protein involved in protein folding, maturation, and trafficking. However, evidence has been accumulating that calreticulin can also negatively regulate the surface expression of certain receptors and channels. In these instances, depletion of calreticulin enhances cell-surface expression and function. In this review, we discuss the role of calreticulin with a focus on its negative effects on the expression of cell-surface proteins. PMID:25230046

  5. 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.

  6. Morphology and movement of corneal surface cells in humans.

    PubMed

    Mathers, W D; Lemp, M A

    1992-06-01

    We examined the morphology of the corneal surface epithelial cells in 13 eyes of 13 subjects using specular microscopy. We determined cell area, perimeter, and shape comparing the central cornea with the inferior and superior periphery. We found surface epithelial cells are significantly smaller in the central cornea. The cells measured 560 +/- 93 square microns in the central cornea, 850 +/- 135 square microns in the superior cornea and 777 +/- 176 square microns in the inferior cornea (p less than .005). Newly emerged surface cells are smaller and are thought to enlarge with time. We postulate that lid shearing forces are greater in the central cornea and contribute to epithelial cell exfoliation. We further postulate that preferential shearing of central corneal surface cells is an important factor driving the centripetal movement of corneal epithelial cells. PMID:1505196

  7. 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

  8. Mesenchymal Stromal Cells Affect Disease Outcomes via Macrophage Polarization.

    PubMed

    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

  9. 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.

  10. Senescence affects endothelial cells susceptibility to dengue virus infection.

    PubMed

    AbuBakar, Sazaly; Shu, Meng-Hooi; Johari, Jefree; Wong, Pooi-Fong

    2014-01-01

    Alteration in the endothelium leading to increased vascular permeability contributes to plasma leakage seen in dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). An earlier study showed that senescent endothelial cells (ECs) altered the ECs permeability. Here we investigated the susceptibility of senescing human umbilical vein endothelial cells (HUVECs) to dengue virus infection and determined if dengue virus infection induces HUVECs senescence. Our results suggest that DENV type-2 (DENV-2) foci forming unit (FFU) and extracellular virus RNA copy number were reduced by at least 35% and 85% in infection of the intermediate young and early senescent HUVECs, respectively, in comparison to infection of young HUVECs. No to low infectivity was recovered from infection of late senescent HUVECs. DENV infection also increases the percentage of HUVECs expressing senescence-associated (SA)-β-gal, cells arrested at the G2/M phase or 4N DNA content stage and cells with enlarged morphology, indicative of senescing cells. Alteration of HUVECs morphology was recorded using impedance-based real-time cell analysis system following DENV-2 infection. These results suggest that senescing HUVECs do not support DENV infection and DENV infection induces HUVECs senescence. The finding highlights the possible role of induction of senescence in DENV infection of the endothelial cells. PMID:24782642

  11. Neuropeptide Y directly affects ovarian cell proliferation and apoptosis.

    PubMed

    Sirotkin, Alexander V; Kardošová, Diana; Alwasel, Saleh Hamad; Harrath, Abdel Halim

    2015-12-01

    The effects of neuropeptide Y (NPY; 0, 10, 100 and 1000 ng/mL) on the expression of PCNA, bax and p53 were examined by immunocytochemistry in porcine luteinized granulosa cells. NPY inhibited proliferation as well as promoted apoptosis and accumulation of p53 in the cells. This is the first report to demonstrate the direct action of NPY on ovarian cell proliferation and apoptosis. The results of the study suggest that the effect is mediated by transcription factor p53. PMID:26679167

  12. Mesenchymal stem cells secretomes' affect multiple myeloma translation initiation.

    PubMed

    Marcus, H; Attar-Schneider, O; Dabbah, M; Zismanov, V; Tartakover-Matalon, S; Lishner, M; Drucker, L

    2016-06-01

    Bone marrow mesenchymal stem cells' (BM-MSCs) role in multiple myeloma (MM) pathogenesis is recognized. Recently, we have published that co-culture of MM cell lines with BM-MSCs results in mutual modulation of phenotype and proteome (via translation initiation (TI) factors eIF4E/eIF4GI) and that there are differences between normal donor BM-MSCs (ND-MSCs) and MM BM-MSCs (MM-MSCs) in this crosstalk. Here, we aimed to assess the involvement of soluble BM-MSCs' (ND, MM) components, more easily targeted, in manipulation of MM cell lines phenotype and TI with specific focus on microvesicles (MVs) capable of transferring critical biological material. We applied ND and MM-MSCs 72h secretomes to MM cell lines (U266 and ARP-1) for 12-72h and then assayed the cells' (viability, cell count, cell death, proliferation, cell cycle, autophagy) and TI (factors: eIF4E, teIF4GI; regulators: mTOR, MNK1/2, 4EBP; targets: cyclin D1, NFκB, SMAD5, cMyc, HIF1α). Furthermore, we dissected the secretome into >100kDa and <100kDa fractions and repeated the experiments. Finally, MVs were isolated from the ND and MM-MSCs secretomes and applied to MM cell lines. Phenotype and TI were assessed. Secretomes of BM-MSCs (ND, MM) significantly stimulated MM cell lines' TI, autophagy and proliferation. The dissected secretome yielded different effects on MM cell lines phenotype and TI according to fraction (>100kDa- repressed; <100kDa- stimulated) but with no association to source (ND, MM). Finally, in analyses of MVs extracted from BM-MSCs (ND, MM) we witnessed differences in accordance with source: ND-MSCs MVs inhibited proliferation, autophagy and TI whereas MM-MSCs MVs stimulated them. These observations highlight the very complex communication between MM and BM-MSCs and underscore its significance to major processes in the malignant cells. Studies into the influential MVs cargo are underway and expected to uncover targetable signals in the regulation of the TI/proliferation/autophagy cascade

  13. Cell surface nucleolin is crucial in the activation of the CXCL12/CXCR4 signaling pathway.

    PubMed

    Yang, Xiangshan; Xu, Zhongfa; Li, Daotang; Cheng, Shaomei; Fan, Kaixi; Li, Chengjun; Li, Aiping; Zhang, Jing; Feng, Man

    2014-01-01

    Recently, CXCL12-CXCR4 has been focused on therapeutic strategies for papillary thyroid carcinoma (PTC) and other cancers. At the same time, cell surface nucleolin is also over-expressed in PTC and others. Interestingly, a few reports suggest that either CXCR4 or cell surface nucleolin is a co-receptor for HIV-1 entry into CD4+ T cells, which indicates that there is a relationship between CXCR4 and nucleolin. In this study, antibody and siRNA were used to identify effects of cell surface nucleolin and CXCR4 on cell signaling; soft-agar colony formation assay and Transwell assay were used to determine roles of nucleolin and CXCR4 in cell proliferation and migration. Importantly, co-immunoprecipitation was used to demonstrate the relationship between CXCR4 and nucleolin. Results showed CXCR4 and nucleolin were co-expressed in PTC cell line K1, B-CPAP, and TPC-1. Either cell surface nucleolin or CXCR4 was necessary to prompt extracellular signal-regulated kinase phosphorylation. When blocked, CXCR4 or nucleolin can significantly affect TPC-1 proliferation and migration (p < 0.01). Co-immunoprecipitation analysis identified that nucleolin can bind and interact with CXCR4 to activate CXCR4 signaling. This study suggests that nucleolin is crucial in the activation of CXCR4 signaling, which affects cell growth, migration, and invasiveness. Further, nucleolin may interact with other receptors. Our study also offers new ideas for cancer therapy. PMID:23918302

  14. 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.

  15. 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

  16. Single cell profiling of surface carbohydrates on Bacillus cereus.

    PubMed

    Wang, Congzhou; Ehrhardt, Christopher J; Yadavalli, Vamsi K

    2015-02-01

    Cell surface carbohydrates are important to various bacterial activities and functions. It is well known that different types of Bacillus display heterogeneity of surface carbohydrate compositions, but detection of their presence, quantitation and estimation of variation at the single cell level have not been previously solved. Here, using atomic force microscopy (AFM)-based recognition force mapping coupled with lectin probes, the specific carbohydrate distributions of N-acetylglucosamine and mannose/glucose were detected, mapped and quantified on single B. cereus surfaces at the nanoscale across the entire cell. Further, the changes of the surface carbohydrate compositions from the vegetative cell to spore were shown. These results demonstrate AFM-based 'recognition force mapping' as a versatile platform to quantitatively detect and spatially map key bacterial surface biomarkers (such as carbohydrate compositions), and monitor in situ changes in surface biochemical properties during intracellular activities at the single cell level. PMID:25505137

  17. Cowpea mosaic virus nanoparticles target surface vimentin on cancer cells

    PubMed Central

    Steinmetz, Nicole F; Cho, Choi-Fong; Ablack, Amber; Lewis, John D; Manchester, Marianne

    2011-01-01

    Aims Vimentin, a type III intermediate filament, is upregulated during epithelial–mesenchymal transition and tumor progression. Vimentin is surface-expressed on cells involved in inflammation; the function remains unknown. We investigated the expression of surface vimentin on cancer cells and evaluated targeting nanoparticles to tumors exploiting vimentin. Materials & methods Cowpea mosaic virus nanoparticles that interact with surface vimentin were used as probes. Tumor homing was tested using the chick chorioallantoic membrane model with human tumor xenografts. Results & discussion Surface vimentin levels varied during cell cycle and among the cell lines tested. Surface vimentin expression correlated with cowpea mosaic virus uptake, underscoring the utility of cowpea mosaic virus to detect invasive cancer cells. Targeting to tumor xenografts was observed; homing was based on the enhanced permeability and retention effect. Our data provide novel insights into the role of surface vimentin in cancer and targeting nanoparticles in vivo. PMID:21385137

  18. Single cell profiling of surface carbohydrates on Bacillus cereus

    PubMed Central

    Wang, Congzhou; Ehrhardt, Christopher J.; Yadavalli, Vamsi K.

    2015-01-01

    Cell surface carbohydrates are important to various bacterial activities and functions. It is well known that different types of Bacillus display heterogeneity of surface carbohydrate compositions, but detection of their presence, quantitation and estimation of variation at the single cell level have not been previously solved. Here, using atomic force microscopy (AFM)-based recognition force mapping coupled with lectin probes, the specific carbohydrate distributions of N-acetylglucosamine and mannose/glucose were detected, mapped and quantified on single B. cereus surfaces at the nanoscale across the entire cell. Further, the changes of the surface carbohydrate compositions from the vegetative cell to spore were shown. These results demonstrate AFM-based ‘recognition force mapping’ as a versatile platform to quantitatively detect and spatially map key bacterial surface biomarkers (such as carbohydrate compositions), and monitor in situ changes in surface biochemical properties during intracellular activities at the single cell level. PMID:25505137

  19. 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

  20. 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

  1. 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.

  2. Lipocalin produced by myelofibrosis cells affects the fate of both hematopoietic and marrow microenvironmental cells.

    PubMed

    Lu, Min; Xia, Lijuan; Liu, Yen-Chun; Hochman, Tsivia; Bizzari, Laetizia; Aruch, Daniel; Lew, Jane; Weinberg, Rona; Goldberg, Judith D; Hoffman, Ronald

    2015-08-20

    Myelofibrosis (MF) is characterized by cytopenias, constitutional symptoms, splenomegaly, and marrow histopathological abnormalities (fibrosis, increased microvessel density, and osteosclerosis). The microenvironmental abnormalities are likely a consequence of the elaboration of a variety of inflammatory cytokines generated by malignant megakaryocytes and monocytes. We observed that levels of a specific inflammatory cytokine, lipocalin-2 (LCN2), were elevated in the plasmas of patients with myeloproliferative neoplasms (MF > polycythemia vera or essential thrombocythemia) and that LCN2 was elaborated by MF myeloid cells. LCN2 generates increased reactive oxygen species, leading to increased DNA strand breaks and apoptosis of normal, but not MF, CD34(+) cells. Furthermore, incubation of marrow adherent cells or mesenchymal stem cells with LCN2 increased the generation of osteoblasts and fibroblasts, but not adipocytes. LCN2 priming of mesenchymal stem cells resulted in the upregulation of RUNX2 gene as well as other genes that are capable of further affecting osteoblastogenesis, angiogenesis, and the deposition of matrix proteins. These data indicate that LCN2 is an additional MF inflammatory cytokine that likely contributes to the creation of a cascade of events that results in not only a predominance of the MF clone but also a dysfunctional microenvironment. PMID:26022238

  3. Physiological variables affecting surface film formation by native lamellar body-like pulmonary surfactant particles.

    PubMed

    Hobi, Nina; Siber, Gerlinde; Bouzas, Virginia; Ravasio, Andrea; Pérez-Gil, Jesus; Haller, Thomas

    2014-07-01

    Pulmonary surfactant (PS) is a surface active complex of lipids and proteins that prevents the alveolar structures from collapsing and reduces the work of breathing by lowering the surface tension at the alveolar air-liquid interface (ALI). Surfactant is synthesized by the alveolar type II (AT II) cells, and it is stored in specialized organelles, the lamellar bodies (LBs), as tightly packed lipid bilayers. Upon secretion into the alveolar lining fluid, a large fraction of these particles retain most of their packed lamellar structure, giving rise to the term lamellar body like-particles (LBPs). Due to their stability in aqueous media, freshly secreted LBPs can be harvested from AT II cell preparations. However, when LBPs get in contact with an ALI, they quickly and spontaneously adsorb into a highly organized surface film. In the present study we investigated the adsorptive capacity of LBPs at an ALI under relevant physiological parameters that characterize the alveolar environment in homeostatic or in pathological conditions. Adsorption of LBPs at an ALI is highly sensitive to pH, temperature and albumin concentration and to a relatively lesser extent to changes in osmolarity or Ca(2+) concentrations in the physiological range. Furthermore, proteolysis of LBPs significantly decreases their adsorptive capacity confirming the important role of surfactant proteins in the formation of surface active films. PMID:24582711

  4. Cell surface modulation of gene expression in brain cells by down regulation of glucocorticoid receptors

    SciTech Connect

    McGinnis, J.F.; de Vellis, J.

    1981-02-01

    The concentration of glycerol-3-phosphate dehydrogenase (GPDH; sn-glycerol-3-phosphate:NAD/sup +/ 2-oxidoreductase, EC 1.1.1.8) had previously been determined to be regulated by glucocorticoids in rat brain cells in vivo and in cell culture. We now demonstrate that concanavalin A (Con A) can inhibit the induction of GPDH in a dose-dependent manner in C6 rat glioma cells and in primary cultures of rat brain oligodendrocytes. The inhibition specifically prevents the appearance of new molecules of GPDH, although Con A does not significantly inhibit protein synthesis in these cells, nor does it affect the activity of another solube enzyme, lactate dehydrogenase. The ability to block enzyme induction is not limited to Con A, because other lectins also inhibit induction. The molecular mechanism by which Con A inhibits GPDH induction appears to be by the down regulation of the cytoplasmic glucocorticoid receptors, because exposure to Con A results in the loss of more than 90% of the receptor activity. Con A does not inhibit the receptor assay and no direct interaction between the receptor and Con A could be demonstrated. This down regulation is not tumor cell specific and appears to be a general phenomenon, because it occurs in normal oligodendrocytes and even in normal astrocytes (a cell type in which the gene for GPDH is not expressed). The down regulation of glucocorticoid receptors in normal brain cells suggests two important corollaries. First, it demonstrates the existence of a rate-limiting step controlling the glucocorticoid-dependent gene expression in brain cells and possibly represents a regulatory site common to all glucocorticoid target cells. Second, it suggests that the response to glucocorticoids of oligodendrocytes and astrocytes can be regulated in vivo by cell surface contact with endogenous lectins, neighboring cells, or both.

  5. Chronic alcohol exposure affects the cell components involved in membrane traffic in neuronal dendrites.

    PubMed

    Romero, Ana M; Renau-Piqueras, Jaime; Marín, M Pilar; Esteban-Pretel, Guillermo

    2015-01-01

    The specific traffic of the membrane components in neurons is a major requirement to establish and maintain neuronal domains-the axonal and the somatodendritic domains-and their polarized morphology. Unlike axons, dendrites contain membranous organelles, which are involved in the secretory pathway, including the endoplasmic reticulum, the Golgi apparatus and post-Golgi apparatus carriers, the cytoskeleton, and plasma membrane. A variety of molecules and factors are also involved in this process. Previous studies have shown that chronic alcohol exposure negatively affects several of these cell components, such as the Golgi apparatus or cytoskeleton in neurons. Yet very little information is available on the possible effects of this exposure on the remaining cell elements involved in intracellular trafficking in neurons, particularly in dendrites. By qualitative and quantitative electron microscopy, immunofluorescence and immunoblotting, we herein show that chronic exposure to moderate levels (30 mM) of ethanol in cultured neurons reduces the volume and surface density of the rough endoplasmic reticulum, and increases the levels of GRP78, a chaperone involved in endoplasmic reticulum stress. Ethanol also significantly diminishes the proportion of neurons that show an extension of Golgi into dendrites and dendritic Golgi outposts, a structure present exclusively in longer, thicker apical dendrites. Both Golgi apparatus types were also fragmented into a large number of cells. We also investigated the effect of alcohol on the levels of microtubule-based motor proteins KIF5, KIF17, KIFC2, dynein, and myosin IIb, responsible for transporting different cargoes in dendrites. Of these, alcohol differently affects several of them by lowering dynein and raising KIF5, KIFC2, and myosin IIb. These results, together with other previously published ones, suggest that practically all the protein trafficking steps in dendrites are altered to a greater or lesser extent by chronic

  6. 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

  7. 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

  8. 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

  9. Glioma cell proliferation controlled by ERK activity-dependent surface expression of PDGFRA.

    PubMed

    Chen, Dongfeng; Zuo, Duo; Luan, Cheng; Liu, Min; Na, Manli; Ran, Liang; Sun, Yingyu; Persson, Annette; Englund, Elisabet; Salford, Leif G; Renström, Erik; Fan, Xiaolong; Zhang, Enming

    2014-01-01

    Increased PDGFRA signaling is an essential pathogenic factor in many subtypes of gliomas. In this context the cell surface expression of PDGFRA is an important determinant of ligand sensing in the glioma microenvironment. However, the regulation of spatial distribution of PDGFRA in glioma cells remains poorly characterized. Here, we report that cell surface PDGFRA expression in gliomas is negatively regulated by an ERK-dependent mechanism, resulting in reduced proliferation of glioma cells. Glioma tumor tissues and their corresponding cell lines were isolated from 14 patients and analyzed by single-cell imaging and flow cytometry. In both cell lines and their corresponding tumor samples, glioma cell proliferation correlated with the extent of surface expression of PDGFRA. High levels of surface PDGFRA also correlated to high tubulin expression in glioma tumor tissue in vivo. In glioma cell lines, surface PDGFRA declined following treatment with inhibitors of tubulin, actin and dynamin. Screening of a panel of small molecule compounds identified the MEK inhibitor U0126 as a potent inhibitor of surface PDGFRA expression. Importantly, U0126 inhibited surface expression in a reversible, dose- and time-dependent manner, without affecting general PDGFRA expression. Treatment with U0126 resulted in reduced co-localization between PDGFRA and intracellular trafficking molecules e.g. clathrin, RAB11 and early endosomal antigen-1, in parallel with enhanced co-localization between PDGFRA and the Golgi cisternae maker, Giantin, suggesting a deviation of PDGFRA from the endosomal trafficking and recycling compartment, to the Golgi network. Furthermore, U0126 treatment in glioma cells induced an initial inhibition of ERK1/2 phosphorylation, followed by up-regulated ERK1/2 phosphorylation concomitant with diminished surface expression of PDGFRA. Finally, down-regulation of surface PDGFRA expression by U0126 is concordant with reduced glioma cell proliferation. These findings

  10. Dry heat treatment affects wheat bran surface properties and hydration kinetics.

    PubMed

    Jacobs, Pieter J; Hemdane, Sami; Delcour, Jan A; Courtin, Christophe M

    2016-07-15

    Heat stabilization of wheat bran aims at inactivation of enzymes which may cause rancidity and processability issues. Such treatments may however cause additional unanticipated phenomena which may affect wheat bran technological properties. In this work, the impact of toasting on wheat bran hydration capacity and hydration kinetics was studied. Hydration properties were assessed using the Enslin-Neff and drainage centrifugation water retention capacity methods, thermogravimetric analysis and contact angle goniometry, next to more traditional methods. While equilibrium hydration properties of bran were not affected by the heat treatment, the rate at which the heat treated bran hydrated was, however, very significantly reduced compared to the untreated bran. This phenomenon was found to originate from the formation of a lipid coating during the treatment rendering the bran surface hydrophobic. These insights help to understand and partially account for the modified processability of heat treated bran in food applications. PMID:26948645

  11. Cigarette smoke extract affects mitochondrial function in alveolar epithelial cells.

    PubMed

    Ballweg, Korbinian; Mutze, Kathrin; Königshoff, Melanie; Eickelberg, Oliver; Meiners, Silke

    2014-12-01

    Cigarette smoke is the main risk factor for chronic obstructive pulmonary disease (COPD). Exposure of cells to cigarette smoke induces an initial adaptive cellular stress response involving increased oxidative stress and induction of inflammatory signaling pathways. Exposure of mitochondria to cellular stress alters their fusion/fission dynamics. Whereas mild stress induces a prosurvival response termed stress-induced mitochondrial hyperfusion, severe stress results in mitochondrial fragmentation and mitophagy. In the present study, we analyzed the mitochondrial response to mild and nontoxic doses of cigarette smoke extract (CSE) in alveolar epithelial cells. We characterized mitochondrial morphology, expression of mitochondrial fusion and fission genes, markers of mitochondrial proteostasis, as well as mitochondrial functions such as membrane potential and oxygen consumption. Murine lung epithelial (MLE)12 and primary mouse alveolar epithelial cells revealed pronounced mitochondrial hyperfusion upon treatment with CSE, accompanied by increased expression of the mitochondrial fusion protein mitofusin 2 and increased metabolic activity. We did not observe any alterations in mitochondrial proteostasis, i.e., induction of the mitochondrial unfolded protein response or mitophagy. Therefore, our data indicate an adaptive prosurvival response of mitochondria of alveolar epithelial cells to nontoxic concentrations of CSE. A hyperfused mitochondrial network, however, renders the cell more vulnerable to additional stress, such as sustained cigarette smoke exposure. As such, cigarette smoke-induced mitochondrial hyperfusion, although part of a beneficial adaptive stress response in the first place, may contribute to the pathogenesis of COPD. PMID:25326581

  12. 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

  13. 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

  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. 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.

  16. 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

  17. 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

  18. 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.

  19. 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

  20. SEM Analysis of MTAD Efficacy for Smear Layer Removal from Periodontally Affected Root Surfaces

    PubMed Central

    Houshmand, B.; Ghandi, M.; Nekoofar, MH.; Gholamii, Gh. A.; Tabor, R. K.; Dummer, P. M. H.

    2011-01-01

    Objective Biopure® MTAD (Dentsply Tulsa Dental, USA) has been developed as a final irrigant following root canal shaping to remove intracanal smear layer. Many of the unique properties of MTAD potentially transfer to the conditioning process of tooth roots during periodontal therapy. The aim of this ex vivo study was to evaluate the effect of MTAD on the removal of smear layer from root surfaces. Materials and Methods Thirty two longitudinally sectioned specimens from 16 freshly extracted teeth diagnosed with advanced periodontal disease were divided into four groups. In group 1 and 2, the root surfaces were scaled using Gracey curettes. In group 3 and 4, 0.5 mm of the root surface was removed using a fissure bur. The specimens in group 1 and 3 were then irrigated by normal saline. The specimens in groups 2 and 4 were irrigated with Biopure MTAD. All specimens were prepared for SEM and scored according to the presence of smear layer. Results MTAD significantly increased (P=0.001) the smear layer removal in both groups 2 and 4 compared to the associated control groups, in which only saline was used. Conclusion MTAD increased the removal of the smear layer from periodontally affected root surfaces. Use of MTAD as a periodontal conditioner may be suggested. PMID:22509454

  1. 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

  2. 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

  3. Claudin-16 affects transcellular Cl− secretion in MDCK cells

    PubMed Central

    Günzel, Dorothee; Amasheh, Salah; Pfaffenbach, Sandra; Richter, Jan F; Kausalya, P Jaya; Hunziker, Walter; Fromm, Michael

    2009-01-01

    Claudin-16 (paracellin-1) is a tight junction protein localized mainly in the thick ascending limb of Henle's loop and also in the distal nephron. Its defect causes familial hypomagnesaemia with hypercalciuria and nephrocalcinosis. This had been taken as an indication that claudin-16 conveys paracellular Mg2+ and Ca2+ transport; however, evidence is still conflicting. We studied paracellular ion permeabilties as well as effects of claudin-16 on the driving forces for passive ion movement. MDCK-C7 cells were stably transfected with wild-type (wt) and mutant (R146T, T233R) claudin-16. Results indicated that paracellular permeability to Mg2+ but not to Ca2+ is increased in cells transfected with wt compared to mutant claudin-16 and control cells. Increased basolateral Mg2+ concentration activated a transcellular Cl− current which was greatly enhanced in cells transfected with wt and T233R claudin-16, as compared to R146T claudin-16-transfected or control cells. This current was triggered by the basolateral calcium-sensing receptor causing Ca2+ release from internal stores, thus activating apical Ca2+-sensitive Cl− channels and basolateral Ca2+-sensitive K+ channels. Immunohistochemical data suggest that the Cl− channel involved is bestrophin. We conclude that claudin-16 itself possesses only moderate paracellular Mg2+ permeability but governs transcellular Cl− currents by interaction with apical Ca2+-activated Cl− channels, presumably bestrophin. As the transepithelial voltage generated by such a current alters the driving force for all ions, this may be the major mechanism to regulate Mg2+ and Ca2+ absorption in the kidney. PMID:19528248

  4. 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.

  5. Biophysical evaluation of cells on nanotubular surfaces: the effects of atomic ordering and chemistry

    PubMed Central

    Shokuhfar, Tolou; Hamlekhan, Azhang; Chang, Jen-Yung; Choi, Chang Kyoung; Sukotjo, Cortino; Friedrich, Craig

    2014-01-01

    After the implantation of a biomaterial in the body, the first interaction occurs between the cells in contact with the biomaterial surface. Therefore, evaluating the cell–substrate interface is crucial for designing a successful implant. In this study, the interaction of MC3T3 osteoblasts was studied on commercially pure and alloy (Ti6Al4V) Ti surfaces treated with amorphous and crystalline titanium dioxide nanotubes. The results indicated that the presence of nanotubes increased the density of osteoblast cells in comparison to bare surfaces (no nanotubes). More importantly, our finding shows that the chemistry of the substrate affects the cell density rather than the morphology of the cells. A novel approach based on the focused ion beam technique was used to investigate the biophysical cell–substrate interaction. The analysis revealed that portions of the cells migrated inside the crystalline nanotubes. This observation was correlated with the super hydrophilic properties of the crystalline nanotubes. PMID:25143725

  6. 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.

  7. Polymer microfilters with nanostructured surfaces for the culture of circulating cancer cells.

    PubMed

    Makarova, Olga V; Adams, Daniel L; Divan, Ralu; Rosenmann, Daniel; Zhu, Peixuan; Li, Shuhong; Amstutz, Platte; Tang, Cha-Mei

    2016-09-01

    There is a critical need to improve the accuracy of drug screening and testing through the development of in vitro culture systems that more effectively mimic the in vivo environment. Surface topographical features on the nanoscale level, in short nanotopography, effect the cell growth patterns, and hence affect cell function in culture. We report the preliminary results on the fabrication, and subsequent cellular growth, of nanoscale surface topography on polymer microfilters using cell lines as a precursor to circulating tumor cells (CTCs). To create various nanoscale features on the microfilter surface, we used reactive ion etching (RIE) with and without an etching mask. An anodized aluminum oxide (AAO) membrane fabricated directly on the polymer surface served as an etching mask. Polymer filters with a variety of modified surfaces were used to compare the effects on the culture of cancer cell lines in blank culture wells, with untreated microfilters or with RIE-treated microfilters. We then report the differences of cell shape, phenotype and growth patterns of bladder and glioblastoma cancer cell lines after isolation on the various types of material modifications. Our data suggest that RIE modified polymer filters can isolate model cell lines while retaining ell viability, and that the RIE filter modification allows T24 monolayering cells to proliferate as a structured cluster. PMID:27207054

  8. 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

  9. 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.

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

    PubMed

    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

  11. Cell surface morphology in epithelial malignancy and its precursor lesions.

    PubMed

    Kenemans, P; Davina, J H; de Haan, R W; van der Zanden, P; Vooys, G P; Stolk, J G; Stadhouders, A M

    1981-01-01

    The cell surface organization of cancer cells is of potentially great significance, as it may not only allow (early) diagnosis, but as it may also harbour markers for refined prognosis (degree of oncogenetic and metastatic potential), and targets for selective cancer (chemo- and immuno) therapy. With these aspects in mind, the present review deals with SEM work done on (pre-) malignant cells, both in vivo and in vitro, and in animal models. Attention, however, is focused on human cancer cells. Cancer cells in vitro may lose many of their original malignant characteristics, and show adaptations to culture conditions. Many other factors have been shown to influence cell surface morphology, such as cell cycle, cell contacts, and preparations technique. Cancer cells differ in their surface morphology from normal cells, and have an extra ordinary amount of surface activity. Human malignant epithelial cells show abundant long. pleomorphic microvilli, especially those present in effusions. In squamous epithelium (bladder, cervix) microridge system present on normal superficial cells are progressively replaced by microvilli which increase in number and degree of pleomorphism during experimental and clinical oncogenesis. The question of whether or not the appearance of long. Pleomorphic microvilli reflects an irreversible alteration of the epithelium, and thus provides an early marker of irreversible neoplastic transformation is considered and assessed on the basis of our work with (pre-) malignant cells of the human uterine cervix. Although SEM has contributed significantly to the description of oncogenesis, up to now it has no early diagnostic, prognostic or therapeutic significance. PMID:7199203

  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. Photoactive branched and linear surface architectures for functional and patterned immobilization of proteins and cells onto surfaces: a comparative study.

    PubMed

    Stegmaier, Petra; del Campo, Aránzazu

    2009-02-01

    Molecular architecture affects the properties of surface layers. Photosensitive silanes with branched architectures allow patterning and coupling of proteins and cells on surfaces while maintaining their biofunctional state. Attachment can be directed to the activated regions of irradiated substrates with high selectivity (see image of mouse fibroblasts). Novel photosensitive silanes with a branched molecular architecture combining three end-functionalized oligoethylene glycol (OEG) and alkyl arms are presented. These molecules are synthesized and applied to the modification of silica surfaces. The resulting layers are tested in their ability for the selective, patterned and functional immobilization of proteins and cells. The results demonstrate and accurately quantify the benefits of branched OEG structures against linear analogues for preventing non-specific interactions with the biological material. Linear structures guarantee high selectivity for the attachment of proteins, however, they fail in the case of cells. Branched structures provide good antifouling properties in both cases and allow the formation of protein patterns with higher densities of the target protein, as well as cell patterns. The results demonstrate the careful balance between surface functionality, composition and architecture that is required for maximizing the performance of any surface-based assay in biology. PMID:19065686

  14. 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.

  15. Collagen Self-Assembly on Orthopedic Magnesium Biomaterials Surface and Subsequent Bone Cell Attachment

    PubMed Central

    Zhao, Nan; Zhu, Donghui

    2014-01-01

    Magnesium (Mg) biomaterials are a new generation of biodegradable materials and have promising potential for orthopedic applications. After implantation in bone tissues, these materials will directly interact with extracellular matrix (ECM) biomolecules and bone cells. Type I collagen, the major component of bone ECM, forms the architecture scaffold that provides physical support for bone cell attachment. However, it is still unknown how Mg substrate affects collagen assembly on top of it as well as subsequent cell attachment and growth. Here, we studied the effects of collagen monomer concentration, pH, assembly time, and surface roughness of two Mg materials (pure Mg and AZ31) on collagen fibril formation. Results showed that formation of fibrils would not initiate until the monomer concentration reached a certain level depending on the type of Mg material. The thickness of collagen fibril increased with the increase of assembly time. The structures of collagen fibrils formed on semi-rough surfaces of Mg materials have a high similarity to that of native bone collagen. Next, cell attachment and growth after collagen assembly were examined. Materials with rough surface showed higher collagen adsorption but compromised bone cell attachment. Interestingly, surface roughness and collagen structure did not affect cell growth on AZ31 for up to a week. Findings from this work provide some insightful information on Mg-tissue interaction at the interface and guidance for future surface modifications of Mg biomaterials. PMID:25303459

  16. 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

  17. 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. PMID:25929464

  18. Surface effects in high voltage silicon solar cells

    NASA Technical Reports Server (NTRS)

    Meulenberg, A.; Arndt, R. A.

    1982-01-01

    The surface of low-resistivity silicon solar cells appears to be a major source of dark diffusion current. This region, consisting of the interface and the adjacent heavily doped layer, therefore, prevents attainment of the high open-circuit voltages expected from these cells. This paper describes the experimental effort carried out to reduce the various contributions of dark current from the surface. Analysis of results from this effort points to means of improving cell voltages by changing processing and structures.

  19. 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

  20. 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

  1. 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

  2. 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

  3. Epoxyeicosatrienoic acids affect electrolyte transport in renal tubular epithelial cells: dependence on cyclooxygenase and cell polarity.

    PubMed

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

    2007-07-01

    We investigated the effects of epoxyeicosatrienoic acids (EETs) on ion transport in the polarized renal distal tubular cell line, Madin-Darby canine kidney (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 (I(sc)) 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. Furthermore, both a Cl(-)-free bath solution and the Ca(2+) antagonist verapamil blocked 5,6-EET-induced ion transport. Although the presence of the PGE(2) receptors EP2, EP3, and EP4 was demonstrated, apically added PGE(2) was ineffective and basolaterally added PGE(2) caused a different kinetics in ion transport compared with 5,6-EET. Moreover, PGE(2) synthesis 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-PGE(1) in 5,6-EET-treated cells, but not in control cells. Indomethacin suppressed the formation of 5,6-dihydroxy-PGE(1). 5,6-Epoxy-PGE(1), the precursor of 5,6-dihydroxy-PGE(1), caused a similar ion transport as 5,6-EET. Cytochrome P-450 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 PGE(2) but by a mechanism, dependent on its conversion to 5,6-epoxy-PGE(1) 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

  4. Potato snakin-1 gene silencing affects cell division, primary metabolism, and cell wall composition.

    PubMed

    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

  5. 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. PMID:27404911

  6. 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.

  7. 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

  8. Surface Plasmon Resonance for Cell-Based Clinical Diagnosis

    PubMed Central

    Yanase, Yuhki; Hiragun, Takaaki; Ishii, Kaori; Kawaguchi, Tomoko; Yanase, Tetsuji; Kawai, Mikio; Sakamoto, Kenji; Hide, Michihiro

    2014-01-01

    Non-invasive real-time observations and the evaluation of living cell conditions and functions are increasingly demanded in life sciences. Surface plasmon resonance (SPR) sensors detect the refractive index (RI) changes on the surface of sensor chips in label-free and on a real-time basis. Using SPR sensors, we and other groups have developed techniques to evaluate living cells' reactions in response to stimuli without any labeling in a real-time manner. The SPR imaging (SPRI) system for living cells may visualize single cell reactions and has the potential to expand application of SPR cell sensing for clinical diagnosis, such as multi-array cell diagnostic systems and detection of malignant cells among normal cells in combination with rapid cell isolation techniques. PMID:24618778

  9. Rapidly rendering cells phagocytic through a cell surface display technique and concurrent Rac activation.

    PubMed

    Onuma, Hiroki; Komatsu, Toru; Arita, Makoto; Hanaoka, Kenjiro; Ueno, Tasuku; Terai, Takuya; Nagano, Tetsuo; Inoue, Takanari

    2014-07-15

    Cell surfaces represent a platform through which extracellular signals that determine diverse cellular processes, including migration, division, adhesion, and phagocytosis, are transduced. Techniques to rapidly reconfigure the surface properties of living cells should thus offer the ability to harness these cellular functions. Although the molecular mechanism of phagocytosis is well characterized, the minimal molecular players that are sufficient to activate this elaborate process remain elusive. We developed and implemented a technique to present a molecule of interest at the cell surface in an inducible manner on a time scale of minutes. We simultaneously induced the cell surface display of the C2 domain of milk fat globule epidermal growth factor factor 8 (MFG-E8) and activated the intracellular small guanosine triphosphatase Rac, which stimulates actin polymerization at the cell periphery. The C2 domain binds to phosphatidylserine, a lipid exposed on the surface of apoptotic cells. By integrating the stimulation of these two processes, we converted HeLa cells into a phagocytic cell line that bound to and engulfed apoptotic human Jurkat cells. Inducing either the cell surface display of the C2 domain or activating Rac alone was not sufficient to stimulate phagocytosis, which suggests that attachment to the target cell and actin reorganization together constitute the minimal molecular events that are needed to induce phagocytosis. This cell surface display technique might be useful as part of a targeted, cell-based therapy in which unwanted cells with characteristic surface molecules could be rapidly consumed by engineered cells. PMID:25028719

  10. Rapidly rendering cells phagocytic through a cell-surface display technique and concurrent Rac activation

    PubMed Central

    Onuma, Hiroki; Arita, Makoto; Hanaoka, Kenjiro; Ueno, Tasuku; Terai, Takuya; Nagano, Tetsuo

    2014-01-01

    Cell surfaces represent a platform through which extracellular signals that determine diverse cellular processes, including migration, division, adhesion, and phagocytosis, are transduced. Techniques to rapidly reconfigure the surface properties of living cells should thus offer the ability to harness these cellular functions. Although the molecular mechanism of phagocytosis is well-characterized, the minimal molecular players that are sufficient to activate this elaborate process remain elusive. We developed and implemented a technique to present a molecule of interest at the cell surface in an inducible manner on a timescale of minutes. We simultaneously induced the cell-surface display of the C2 domain of milk fat globule-EGF factor 8 (MFG-E8) and activated the intracellular small guanosine triphosphatase Rac, which stimulates actin polymerization at the cell periphery. The C2 domain binds to phosphatidylserine, a lipid exposed on the surface of apoptotic cells. By integrating the stimulation of these two processes, we converted HeLa cells into a phagocytic cell line that bound to and engulfed apoptotic human Jurkat cells. Inducing either the cell-surface display of the C2 domain or activating Rac alone was not sufficient to stimulate phagocytosis, which suggests that attachment to the target cell and actin reorganization together constitute the minimal molecular events that are needed to induce phagocytosis. This cell-surface display technique might be useful as part of a targeted, cell-based therapy in which unwanted cells with characteristic surface molecules could be rapidly consumed by engineered cells. PMID:25028719

  11. Bearing surface design changes affect contact patterns in total knee arthroplasty.

    PubMed

    Cottrell, Jocelyn M; Townsend, Elizabeth; Lipman, Joseph; Sculco, Thomas P; Wright, Timothy M

    2007-11-01

    The impact of design changes intended to improve wear of knee replacements can be assessed from analysis of retrieved implants. We hypothesized changes in bearing surface conformity from the Insall-Burstein II knee to a successor, the Optetrak, intended to improve contact stresses would be apparent in wear patterns observed on retrieved tibial inserts. From 151 Insall-Burstein II and 54 Optetrak retrieved components, 35 pairs (Insall-Burstein II and Optetrak) were matched on length of implantation, body mass index, and age. Digital images of the bearing surfaces were used to identify and measure wear modes, which were then converted to a percentage of the total possible contact area. Burnishing was the most prevalent mode for both designs followed by scratching and then pitting. The percentage of involved area was greater for the Optetrak for 23 pairs. Interestingly, for the nine matched pairs with length of implantation longer than 2 years, six of the Insall-Burstein II inserts had considerably greater scratching and pitting and five exhibited abrasion and creep absent from Optetrak implants. Bearing surface design is a major factor that can affect kinematics and contact patterns. Our observations confirm the considerable impact of small changes in conformity and suggest models predicting contact stresses adequately reflect in vivo performance. PMID:18062045

  12. 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

  13. 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.

  14. Attachment and Invasion of Neisseria meningitidis to Host Cells Is Related to Surface Hydrophobicity, Bacterial Cell Size and Capsule

    PubMed Central

    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. PMID:23405216

  15. Surface passivation of high efficiency silicon solar cells

    NASA Astrophysics Data System (ADS)

    Aberle, A.; Warta, W.; Knobloch, J.; Voss, B.

    Theoretically and experimentally determined design guides for significantly reducing recombination at the emitter and rear surfaces of full-area Al-BSF (back-surface region) and oxide-passivated bifacial cells are given. The impact of emitter thickness and surface dopant concentration on emitter saturation current and solar cell efficiency is outlined. A modified emitter structure (locally deep diffused below the metal contacts) is predicted to have superior performance. Measured Voc values reveal the potential of deep emitter cells to achieve efficiencies above 20 percent in spite of high metallization factors. Experimentally, a strong dependence of passivation quality on oxide thickness and base doping concentration is found. The BSF quality of a diffused aluminum layer decreases strongly with increasing drive-in time. For SiO2-passivated rear surfaces of bifacial cells, measurements of the dependence of the surface recombination velocity on the excess carrier concentration are presented.

  16. Exogenous gangliosides may affect methylation mechanisms in neuronal cell cultures

    SciTech Connect

    Ferret, B.; Hubsch, A.; Dreyfus, H.; Massarelli, R. )

    1991-02-01

    Primary neurons in culture from chick embryo cerebral hemispheres were treated with a mixture of gangliosides added to the growth medium (final concentration: 10(-5)M and 10(-8)M) from the 3rd to the 6th day in vitro. Under these conditions methylation processes measured with (3H) and (35S) methionine and (3H)ethanolamine as precursors showed an increased methylation of (3H)ethanolamine containing phospholipids, a correspondent increased conversion of these compounds to (3H)choline containing phospholipids, and a general increased methylation of trichloroacetic acid precipitable macromolecules containing labeled methionine. A small increase in protein synthesis was observed after incubation of neurons with (3H)- and (35S)methionine. This was confirmed after electrophoretic separation of a protein extract with increased 3H- and 35S-labeling in protein bands with moecular weights between 50 and 60 KDaltons. A protein band of about 55 KDaltons appeared to be preferentially labelled when (3H) methionine was the precursor. The treatment with gangliosides increased the incorporation of (methyl-3H) label after incubation of neurons with (3H) methionine, into total DNA and decreased that of total RNA. The treatment of neurons in culture with exogenous gangliosides hence affects differently methylation processes, a finding which may confirm the involvement of gangliosides on the intracellular mediation of neuronal information mechanisms.

  17. Immobilization of microbial cells on cellulose-polymer surfaces by radiation polymerization

    SciTech Connect

    Kumakura, M.; Kaetsu, I.

    1983-12-01

    Streptomyces phaeochromogens cells were immobilized on cellulose-polymer surfaces by radiation polymerization using hydrophilic monomers and paper. The enzyme activity of immobilized cell sheets was higher than that of immobilized cell composites obtained by the usual radiation polymerization technique. The enzyme activity of the sheets was affected by monomer concentration, the thickness of paper, and the degree of polymerization of paper. The copolymerization of hydroxyethyl methacrylate and methoxytetraethyleneglycol methacrylate in the sheets led to a further increase of the enzyme activity due to the increase of the hydrophilicity of the polymer matrix. The Michaelis constant of the sheets from low monomer concentration was close to that of intact cells.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Cell Surface Galactosylation Is Essential for Nonsexual Flocculation in Schizosaccharomyces pombe

    PubMed Central

    Tanaka, Naotaka; Awai, Atsuro; Bhuiyan, M. Shah Alam; Fujita, Kiyotaka; Fukui, Hiroshi; Takegawa, Kaoru

    1999-01-01

    We have isolated fission yeast mutants that constitutively flocculate upon growth in liquid media. One of these mutants, the gsf1 mutant, was found to cause dominant, nonsexual, and calcium-dependent aggregation of cells into flocs. Its flocculation was inhibited by the addition of galactose but was not affected by the addition of mannose or glucose, unlike Saccharomyces cerevisiae FLO mutants. The gsf1 mutant coflocculated with Schizosaccharomyces pombe wild-type cells, while no coflocculation was found with galactose-deficient (gms1Δ) cells. Moreover, flocculation of the gsf1 mutant was also inhibited by addition of cell wall galactomannan from wild-type cells but not from gms1Δ cells. These results suggested that galactose residues in the cell wall glycoproteins may be receptors of gsf1-mediated flocculation, and therefore cell surface galactosylation is required for nonsexual flocculation in S. pombe. PMID:9973368

  4. 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

  5. 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.

  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. Soil factors affecting mycorrhizal use in surface mine reclamation. Information circular/1993

    SciTech Connect

    Norland, M.R.

    1993-01-01

    Surface and subsurface stabilization of mining-related wastes through revegetation depends upon the physical, chemical, and biological condition of the waste following mining. Mining disturbances can significantly alter the soil physical, chemical, and biological characteristics of a site, reducing or eliminating mycorrhizal fungi from the soil. Mycorrhizae are economically and ecologically important because they can alleviate environmental stresses caused by lack of proper soil condition and because they are vital to stabilization of mining waste by increasing plant survival and biomass through increased nutrient and water uptake. The report discusses some of the ecological factors that may affect mycorrhizae-plant associations on mining-related wastes and provides general information on mycorrhizae inoculation technology.

  8. 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

  9. Hydroxyapatite surface roughness: complex modulation of the osteoclastogenesis of human precursor cells.

    PubMed

    Costa-Rodrigues, João; Fernandes, Anabela; Lopes, Maria A; Fernandes, Maria H

    2012-03-01

    It is recognized that the surface roughness affects osteoblastic differentiation, but little information is available regarding its effect on osteoclastogenesis. With this work, the osteoclastogenic behaviour of human peripheral blood mononuclear cells (PBMCs), cultured isolated (1.5×10(6)cellscm(-2)) or co-cultured with human bone marrow cells (hBMCs; 10(3)cellscm(-2)), was assessed on surface-abraded hydroxyapatite disks with three different surface roughnesses (R(a) 0.0437-0.582 μm). Monocultures and co-cultures were performed for 21 days in the absence or presence of recombinant M-CSF and RANKL. Results showed that PBMCs supplemented with M-CSF and RANKL or co-cultured with hBMCs displayed typical osteoclastic features, i.e. multinucleated cells with actin rings, vitronectin and calcitonin receptors, gene expression of TRAP, cathepsin K, carbonic anhydrase 2, c-myc and c-src, TRAP activity and resorbing activity. The osteoclastogenic response increased with surface roughness in PBMCs cultured with M-CSF and RANKL but decreased in PBMCs co-cultured with hBMCs. However, co-cultures supplemented with the osteoclastogenic inducers displayed high and similar levels of osteoclast differentiation in the three tested surfaces. In conclusion, modulation of osteoclast differentiation by surface roughness seemed to be dependent on the mechanisms subjacent to the osteoclastogenic stimulus, i.e. the presence of soluble factors or direct cell-to-cell contacts between osteoblastic and osteoclastic cells. PMID:22178652

  10. Changes of cell-surface thiols and intracellular signaling in human monocytic cell line THP-1 treated with diphenylcyclopropenone.

    PubMed

    Hirota, Morihiko; Motoyama, Akira; Suzuki, Mie; Yanagi, Masashi; Kitagaki, Masato; Kouzuki, Hirokazu; Hagino, Shigenobu; Itagaki, Hiroshi; Sasa, Hitoshi; Kagatani, Saori; Aiba, Setsuya

    2010-12-01

    Changes of cell-surface thiols induced by chemical treatment may affect the conformations of membrane proteins and intracellular signaling mechanisms. In our previous study, we found that a non-toxic dose of diphenylcyclopropene (DPCP), which is a potent skin sensitizer, induced an increase of cell-surface thiols in cells of a human monocytic cell line, THP-1. Here, we examined the influence of DPCP on intracellular signaling. First, we confirmed that DPCP induced an increase of cell-surface thiols not only in THP-1 cells, but also in primary monocytes. The intracellular reduced-form glutathione/oxidized-form glutathione ratio (GSH/GSSG ratio) was not affected by DPCP treatment. By means of labeling with a membrane-impermeable thiol-reactive compound, Alexa Fluor 488 C5 maleimide (AFM), followed by two-dimensional gel electrophoresis and analysis by liquid chromatography coupled with electrospray tandem mass spectrometry (LC/MS/MS), we identified several proteins whose thiol contents were modified in response to DPCP. These proteins included cell membrane components, such as actin and β-tubulin, molecular chaperones, such as heat shock protein 27A and 70, and endoplasmic reticulum (ER) stress-inducible proteins. Next, we confirmed the expression in DPCP-treated cells of spliced XBP1, a known marker of ER stress. We also detected the phosphorylation of SAPK/JNK and p38 MAPK, which are downstream signaling molecules in the IRE1α-ASK1 pathway, which is activated by ER stress. These data suggested that increase of cell-surface thiols might be associated with activation of ER stress-mediated signaling. PMID:21139337

  11. B-cell acquisition of antigen: Sensing the surface.

    PubMed

    Knight, Andrew M

    2015-06-01

    B-cell antigen receptor (BCR) recognition and acquisition of antigen by B cells is the essential first step in the generation of effective antibody responses. As B-cell-mediated antigen presentation is also believed to play a significant role in the activation of CD4(+) Th-cell responses, considerable effort has focused on clarifying the nature of antigen/BCR interactions. Following earlier descriptions of interactions of soluble antigens with the BCR, it is now clear that B cells also recognize, physically extract and present antigens that are tethered to, or integral components of, the surfaces or extracellular matrix of other cells. In this issue of the European Journal of Immunology, Zeng et al. [Eur. J. Immunol. 2015. 45: XXXX-XXXX] examine how the physical property or "stiffness" of the surface displaying antigens to B cells influences the B-cell response. This commentary reports that antigen tethered on "less stiff" surfaces induces increased B-cell activation and antibody responses. I then infer how "sensing the surface" by B cells may represent a new component of the immune system's ability to detect "damage," and how this understanding may influence approaches to clinical therapies where immune activity is either unwanted or desired. PMID:25929718

  12. Fibronectin adsorption, cell adhesion, and proliferation on nanostructured tantalum surfaces.

    PubMed

    Dolatshahi-Pirouz, A; Jensen, T; Kraft, David Christian; Foss, Morten; Kingshott, Peter; Hansen, John Lundsgaard; Larsen, Arne Nylandsted; Chevallier, Jacques; Besenbacher, Flemming

    2010-05-25

    The interaction between dental pulp derived mesenchymal stem cells (DP-MSCs) and three different tantalum nanotopographies with and without a fibronectin coating is examined: sputter-coated tantalum surfaces with low surface roughness <0.2 nm, hut-nanostructured surfaces with a height of 2.9 +/- 0.6 nm and a width of 35 +/- 8 nm, and dome structures with a height of 13 +/- 2 nm and a width of 52 +/- 14 nm. Using ellipsometry, the adsorption and the availability of fibronectin cell-binding domains on the tantalum surfaces were examined, as well as cellular attachment, proliferation, and vinculin focal adhesion spot assembly on the respective surfaces. The results showed the highest fibronectin mass uptake on the hut structures, with a slightly higher availability of cell-binding domains and the most pronounced formation of vinculin focal adhesion spots as compared to the other surfaces. The proliferation of DP-MSCs was found to be significantly higher on dome and hut surfaces coated with fibronectin compared to the uncoated flat tantalum surfaces. Consequently, the results presented in this study indicate that fibronectin-coated nanotopographies with a vertical dimension of less than 5 nm influence cell adhesion. This rather interesting behavior is argued to originate from the more available fibronectin cell-binding domains observed on the hut structures. PMID:20443575

  13. Surface morphology of hamster (Mesocricetus auratus) decidual cells in vitro.

    PubMed

    Shukla, R; Pande, S; Mehrotra, P K; Maitra, S C; Kamboj, V P

    1995-02-01

    Cell surface morphology of hamster decidual cells isolated from day 8 implantation swellings was studied, using both phase-contrast and scanning electron microscopy. Two kinds of cells, fibroblastic and epithelioid, were identified in cultures examined by phase-contrast microscopy. Fibroblastic cells were spindle-shaped, having pointed or blunt terminals on one end and bifid or webbed projections at the other end. Epithelioid cells, on the other hand, were flat and discoid, having a distinctively ruffled plasma membrane. Further, the plasma membrane of epithelioid cells formed rope-like or flange-like processes. The significance of such adaptations is discussed. PMID:7877182

  14. 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. PMID:26645388

  15. The microbial cell surface electric field: life in an ion cloud

    NASA Astrophysics Data System (ADS)

    Yee, N.

    2005-05-01

    Electrical charge on microbial cell surfaces arises from the ionization of proton-active functional groups attached to cell wall polymers. In Gram-positive cell walls, ionizable functional groups are associated with peptidoglycan and secondary polymers such as teichoic or teichuronic acids. Carboxyl functional groups attached to the unlinked peptide crosslinks of peptidoglycan and phosphoryl groups associated with the teichoic acids can deprotonate to form negatively charged surface sites. These anionic functional groups generate charge in the cell wall which results in the formation of an electric field that surrounds the entire cell. The cell surface electric field controls the concentration and spatial distribution of ions and counterions at the cell-water interface, and strongly affects microbe-fluid and microbe-mineral interactions. Recently, we have used potentiometric titration, infrared spectroscopy, electrophoretic mobility, metal sorption experiments to characterize the surface electrical potential properties of the various Gram-positive and Gram-negative bacterial species. Potentiometric titration experiments show that the deprotonation of acidic cell wall functional groups generate surface charge density values typically ranging from 1.1 to 2.2 mol sites/g of bacteria. Spectroscopic measurements have confirmed that the dominant proton-active sites in the cell wall are carboxyl functional groups. Electrophoretic mobility experiments show that the magnitude of the electrostatic surface potential increases with increasing pH, and decreases with increasing ionic strength. Metal sorption experiments conducted with Ca(II), Sr(II) and Ba(II) exhibit strong ionic strength dependence, suggesting that high concentrations of metal ions are electrostatically bound to bacterial cell walls via outer-sphere complexation. We demonstrate that the electrostatic potential effects on ion sorption at the cell-water interface can be quantified using the Donnan model.

  16. Factors Affecting the Development of Somatic Cell Nuclear Transfer Embryos in Cattle

    PubMed Central

    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. PMID:25341701

  17. 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

  18. 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

  19. 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.

  20. 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

  1. Changes in cell surface properties of shiga toxigenic Escherichia coli by Quercus infectoria G. Olivier.

    PubMed

    Voravuthikunchai, Supayang Piyawan; Suwalak, Sakol

    2009-08-01

    The effects of Quercus infectoria (family Fagaceae) nutgalls on cell surface properties of Shiga toxigenic Escherichia coli (STEC) were investigated with an assay of microbial adhesion to hydrocarbon. The surface of bacterial cells treated with Q. infectoria exhibited a higher level of cell surface hydrophobicity (CSH) toward toluene than did the surface of untreated cells. With 50% ethanolic extract, the CSH of the three strains of STEC O157:H7 treated with 4X MIC of the extract resulted in moderate or strong hydrophobicity, whereas at 2x MIC and MIC, the CSH of only one strain of E. coli O157:H7 was significantly affected. The 95% ethanolic extract had a significant effect on CSH of all three strains at both 4X MIC and 2X MIC but not at the MIC. The effect on bacterial CSH was less pronounced with the other STEC strains. At 4X MIC, the 50% ethanolic extract increased the CSH of all non-O157 STEC strains significantly. At 2X MIC and 4X MIC, the 95% ethanolic extract affected the CSH of E. coli O26:H11 significantly but did not affect E. coli O111 :NM or E. coli O22. Electro microscopic examination revealed the loss of pili in the treated cells. The ability of Q. infectoria extract to modify hydrophobic domains enables this extract to partition the lipids of the bacterial cell membrane, rendering the membrane more permeable and allowing leakage of ions and other cell contents, which leads to cell death. Further studies are required to evaluate the effects of Q. infectoria extract in food systems or in vivo and provide support for the use of this extract as a food additive for control of these STEC pathogens. PMID:19722403

  2. A glycosylation mutation affects cell fate in chimeras of Dictyostelium discoideum.

    PubMed Central

    Houle, J; Balthazar, J; West, C M

    1989-01-01

    Prestalk and prespore cells form a simple pattern in the pseudoplasmodium of the cellular slime mold Dictyostelium discoideum. Prestalk cells are distinguished from prespore cells by a low level of expression of a glycoantigen on their surfaces and by reduced intercellular cohesion. We examined the possible significance of these differences, using the modB mutation, which eliminates this glycoantigen genetically, leading to reduced intercellular cohesion, modB mutant cells were allowed to develop together with normal cells to form chimeric slugs. Mutant cells labeled by feeding with fluorescent bacteria were highly enriched in the prestalk cell zone at the anterior end of the slug. In contrast, normal cells, if in a minority, were concentrated in the rear part of the prespore cell zone. Immunoblot analysis and cell-by-cell double-label immunofluorescence of these mixtures showed that mutant cells underproduced several prespore cell markers. Mutant cells tended not to form spores in chimeras unless they exceeded a threshold proportion of ca. 30%. However, mutant cells showed no tendency to produce excess prestalk cells when allowed to develop alone. These findings are most simply explained by postulating that reduced glycoantigen expression and intercellular adhesion encourage a more anterior cell localization, which in turn causes differentiation into a prestalk cell. Since normal prestalk cells also show reduced glycoantigen expression and intercellular adhesion, this suggests that a similar mechanism may contribute to pattern formation during normal development. Images PMID:2726746

  3. 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

  4. 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

  5. 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

  6. Investigation of the competition between cell/surface and cell/cell interactions during neuronal cell culture on a micro-engineered surface.

    PubMed

    Béduer, Amélie; Gonzales-Calvo, Inès; Vieu, Christophe; Loubinoux, Isabelle; Vaysse, Laurence

    2013-11-01

    To investigate the respective roles of topography and cell/cell interactions in the development of a guided neuronal network on an engineered surface, micropatterned PDMS substrates were generated with different microgrooves geometry and investigated for the influence of cell density on neurite outgrowth and alignment. Through this systematic investigation, using a human neuronal stem cell line, the rules of neuronal network development and guiding could be learned. The results show that when cell density is increased the influence on neuritic outgrowth and alignment is very different for the various grooves geometries. The data emphasized the competition, in neurite development, between physical cues brought by surface topographical features and cell to cell communications. These results can be of particular interest for designing functional neuronal networks with a controlled architecture. PMID:24039002

  7. F 2 excimer laser (157 nm) radiation modification and surface ablation of PHEMA hydrogels and the effects on bioactivity: Surface attachment and proliferation of human corneal epithelial cells

    NASA Astrophysics Data System (ADS)

    Zainuddin; Chirila, Traian V.; Barnard, Zeke; Watson, Gregory S.; Toh, Chiong; Blakey, Idriss; Whittaker, Andrew K.; Hill, David J. T.

    2011-02-01

    Physical and chemical changes at the surface of poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels modified by ablation with an F 2 excimer laser were investigated experimentally. An important observation was that only the outer exposed surface layers of the hydrogel were affected by the exposure to 157 nm radiation. The effect of the surface changes on the tendency of cells to adhere to the PHEMA was also investigated. A 0.5 cm 2 area of the hydrogel surfaces was exposed to laser irradiation at 157 nm to fluences of 0.8 and 4 J cm -2. The changes in surface topography were analysed by light microscopy and atomic force microscopy, while the surface chemistry was characterized by attenuated total reflection infrared and X-ray photoelectron spectroscopies. Cell-interfacial interactions were examined based on the proliferation of human corneal limbal epithelial (HLE) cells cultured on the laser-modified hydrogels, and on the unexposed hydrogels and tissue culture plastic for comparison. It was observed that the surface topography of laser-exposed hydrogels showed rippled patterns with a surface roughness increasing at the higher exposure dose. The changes in surface chemistry were affected not only by an indirect effect of hydrogen and hydroxyl radicals, formed by water photolysis, on the PHEMA, but also by the direct action of laser radiation on PHEMA if the surface layers of the gel become depleted of water. The laser treatment led to a change in the surface characteristics, with a lower concentration of ester side-chains and the formation of new oxygenated species at the surface. The surface also became more hydrophobic. Most importantly, the surface chemistry and the newly created surface topographical features were able to improve the attachment, spreading and growth of HLE cells.

  8. Early cell response to contact with biomaterial's surface.

    PubMed

    Komorowski, Piotr; Walkowiak-Przybyło, Magdalena; Walkowiak, Bogdan

    2016-07-01

    Most biomaterials at present have sufficient mechanical properties; however compliance with standards for biocompatibility is often not sufficient in clinical practice. This may be due to the complexity of biological systems in general and the diversity of individual responses to these materials by implant recipients. Significant improvement of biocompatibility must involve surface modification of implants, which in the future will make it possible to introduce individually selected types of surface modification for individual recipients. The key to this technology seems to be understanding the processes occurring at the site of contact of the implant with the tissue. Processes resulting from the stress generated by the contact of the biomaterial surfaces were observed with endothelial cells line EA.hy926, and it was demonstrated that differently modified surfaces of medical steel (polished medical steel and medical steel coated with Parylene C and nanocrystalline diamond) cause diverse cellular response in cells grown on these surfaces, on both the cellular (cell morphology and cell survival) and molecular (transcriptome and proteome profiles) levels. The herein presented observations are a good starting point not only for further research and the development of far-reaching personalization of medical implants, but also to study the potential use of cells as a specific sensor capable of recognizing different surfaces with which these cells come into contact. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 880-893, 2016. PMID:25951795

  9. Cell adhesion property affected by cyclooxygenase and lipoxygenase: Opto-electric approach.

    PubMed

    Choi, Chang Kyoung; Sukhthankar, Mugdha; Kim, Chul-Ho; Lee, Seong-Ho; English, Anthony; Kihm, Kenneth D; Baek, Seung Joon

    2010-01-15

    Expression of cyclooxygenases (COX) and lipoxygenases (LOX) has been linked to many pathophysiological phenotypes, including cell adhesion. However, many current approaches to measure cellular changes are performed only in a fixed-time point. Since cells dynamically move in conjunction with the cell matrix, there is a pressing need for dynamic or time-dependent methods for the investigation of cell properties. In the presented study, we used stable human colorectal cancer cell lines ectopically expressing COX-1, COX-2, and 15LOX-1, to investigate whether expression of COX-1, COX-2, or 15LOX-1 would affect cell adhesion using our opto-electric methodology. In a fixed-time point experiment, only COX-1- and COX-2-expressing cells enhanced phosphorylation of focal adhesion kinase, but all the transfected cells showed invasion activity. However, in a real-time experiment using opto-electric approaches, transmitted cellular morphology was much different with tight adhesion being shown in COX-2 expressing cells, as imaged by differential interference contrast microscopy (DICM) and interference reflection contrast microscopy (IRCM). Furthermore, micro-impedance measurements showed a continued increase in both resistance and reactance of COX- and LOX-transfected cells, consistent with the imaging data. Our data indicate that both COX- and LOX-expressing cells have strong cell-to-cell and cell-to-substrate adhesions, and that cell imaging analysis with cell impedance data generates fully reliable results on cell adhesion measurement. PMID:20026301

  10. Glyceroglycolipids Affect Uptake of Carotenoids Solubilized in Mixed Micelles by Human Intestinal Caco-2 Cells.

    PubMed

    Kotake-Nara, Eiichi; Yonekura, Lina; Nagao, Akihiko

    2015-09-01

    We previously reported that phospholipids markedly affected the uptake of carotenoids solubilized in mixed micelles by human intestinal Caco-2 cells. In the present study, we found that two classes of dietary glyceroglycolipids and the corresponding lysoglyceroglycolipids affected uptake of β-carotene and lutein by differentiated Caco-2 cells. The levels of carotenoid uptake from micelles containing digalactosyldiacylglycerol or sulfoquinovosyldiacylglycerol were significantly lower than that from control micelles. On the other hand, the uptakes from micelles containing digalactosylmonoacylglycerol or sulfoquinovosylmonoacylglycerol were significantly higher than that from control micelles. In dispersed cells and Caco-2 cells with poor cell-to-cell adhesion, however, the levels of uptake from micelles containing these lyso-lipids were much lower than that from control micelles. The uptake levels from control micelles were markedly decreased depending on the development of cell-to-cell/cell-matrix adhesion in Caco-2 cells, but the uptake levels from the micelles containing these lyso-lipids were not substantially changed, suggesting that the intercellular barrier formed by cell-to-cell/cell-matrix adhesion inhibited the uptake from control micelles, but not from the lyso-lipid-containing micelles. The lyso-lipids appeared to enhance carotenoid uptake by decreasing the intercellular barrier integrity. The results showed that some types of glyceroglycolipids have the potential to modify the intestinal uptake of carotenoids. PMID:26012480

  11. 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

  12. 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.

  13. 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.

  14. Heparanase: Busy at the cell surface

    PubMed Central

    Fux, Liat; Ilan, Neta; Sanderson, Ralph D.; Vlodavsky, Israel

    2009-01-01

    Heparanase activity is strongly implicated in structural remodeling of the extracellular matrix underlying tumor and endothelial cells that leads to cellular invasion. In addition, heparanase augments signaling cascades leading to enhanced phosphorylation of selected protein kinases and increased gene transcription associated with aggressive tumor progression. This function is apparently independent of heparan sulfate and enzyme activity and is mediated by a novel protein domain localized at the heparanase C-terminus (C-domain). Moreover, the functional repertoire of heparanase is expanded by its regulation of syndecan clustering, shedding, and mitogen binding. Recently, modified glycol-split heparin that inhibits heparanase activity was demonstrated to profoundly inhibit the progression of tumor xenografts produced by myeloma and carcinoma cells thus moving anti-heparanase therapy closer to reality. PMID:19733083

  15. Engineering biomaterial surfaces using nanoparticle assemblies: A new paradigm for modulating cell function

    NASA Astrophysics Data System (ADS)

    Lipski, Anna Marie

    Silica nanoparticles (NP) were investigated as a surface modification medium and their impact on cell function was studied. This work has demonstrated that NP assemblies are suitable for the surface modification of both metal and polymer substrates. Additionally, important surface parameters, such as nano-roughness, charge, and chemistry, can be imparted in a predictable manner. More importantly, by varying the NP size, nano-roughness of a surface can be varied independent of chemistry. Two terminally differentiated mammalian cell types, bovine aortic endothelial cells (BAEC) and murine calvarial osteoblast-like cells (MC3T3-E1), were used to probe the effects of nano-topography on cell proliferation, metabolic activity, spreading, cytoskeletal F-actin alignment, and focal adhesion recruitment. Furthermore, the influence of nano-topography on cell migration was studied using BAEC and human fetal osteoblasts (hFOB). The results suggested that surface nano-rugosity affects cell behavior at various levels and that these effects are cell type specific; however, some clear trends were discerned with respect to F-actin alignment and cell migration. In particular, presentation of nano-features resulted in enhancement of cytoskeletal F-actin alignment along the long axis of the cells in comparison to unmodified glass. With respect to cell migration, increased nano-roughness resulted in decreased migration rates for both BAEC and hFOB. Finally, the potential of nano-rugosity as a mediator of cell differentiation was investigated by following the lineage specific differentiation of human marrow-derived mesenchymal progenitor cells (MPC) on NP-modified 316L stainless steel and titanium substrates. It was observed that NP modification enhanced the differentiation of MPC into an osteogenic lineage and that rugosity appeared to be the dominant factor in directing this differentiation. Thus, coatings composed of silica NPs presented a new paradigm that may lend themselves to

  16. 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

  17. Transforming ocular surface stem cell research into successful clinical practice

    PubMed Central

    Sangwan, Virender S; Jain, Rajat; Basu, Sayan; Bagadi, Anupam B; Sureka, Shraddha; Mariappan, Indumathi; MacNeil, Sheila

    2014-01-01

    It has only been a quarter of a century since the discovery of adult stem cells at the human corneo-scleral limbus. These limbal stem cells are responsible for generating a constant and unending supply of corneal epithelial cells throughout life, thus maintaining a stable and uniformly refractive corneal surface. Establishing this hitherto unknown association between ocular surface disease and limbal dysfunction helped usher in therapeutic approaches that successfully addressed blinding conditions such as ocular burns, which were previously considered incurable. Subsequent advances in ocular surface biology through basic science research have translated into innovations that have made the surgical technique of limbal stem cell transplantation simpler and more predictable. This review recapitulates the basic biology of the limbus and the rationale and principles of limbal stem cell transplantation in ocular surface disease. An evidence-based algorithm is presented, which is tailored to clinical considerations such as laterality of affliction, severity of limbal damage and concurrent need for other procedures. Additionally, novel findings in the form of factors influencing the survival and function of limbal stem cells after transplantation and the possibility of substituting limbal cells with epithelial stem cells of other lineages is also discussed. Finally this review focuses on the future directions in which both basic science and clinical research in this field is headed. PMID:24492499

  18. 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. PMID:26025340

  19. Unit cell finite element modelling for ultrasonic scattering from periodic surfaces

    NASA Astrophysics Data System (ADS)

    Choi, W.; Skelton, E.; Lowe, M. J. S.; Craster, R.

    2013-01-01

    Ultrasound wave scattering from the rough surfaces of defects is an important consideration for the qualification of safety-critical inspections because some species of fabrication and service-induced defects are rough. Whereas the surfaces of flat defects only reflect specularly, an incident wave reflects over a range of angles when the surface is rough. This affects the inspection performance because the coefficient of the specular reflection is reduced, while the detection of reflections at other angles becomes possible. An infinite periodic surface is a simple form of rough surface, which has been well investigated since Rayleigh, and can be useful to provide general insight into the nature of the wave scattering. Furthermore, in the context of scattering from cracks, the study of an infinite surface enables examination of the reflections from the surface and behavior at the surface without the presence of the crack tip diffraction fields. In this paper, an infinite periodic surface is modelled by a unit cell FE model with cyclic symmetric boundary conditions, allowing the model to be small, and elastic wave scattering from the surface is simulated in the time domain. This cell model is demonstrated using the commercial FE package ABAQUS and examples of the scattered wave results are compared with large FE model results.

  20. Zinc uptake by brain cells: `surface' versus `bulk'

    NASA Astrophysics Data System (ADS)

    DeStasio, Gelsomina; Pochon, S.; Lorusso, G. F.; Tonner, B. P.; Mercanti, Delio; Ciotti, M. Teresa; Oddo, Nino; Galli, Paolo; Perfetti, P.; Margaritondo, G.

    1996-08-01

    The uptake of zinc by cerebellar rat cultures upon exposure to 0022-3727/29/8/023/img12 solutions was comparatively investigated using two well known condensed matter physics techniques: synchrotron photoelectron spectromicroscopy and inductively coupled plasma atomic emission spectroscopy. The objective was to apply a strategy - well known in surface physics - to distinguish between `surface' and `bulk' phenomena. The results clearly demonstrate that exposure significantly enhances the bulk (cell cytoplasm) Zn concentration with respect to the physiological level, whereas the effect on the surface (cell membrane) is negligible.

  1. 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

  2. Sialylation of cell surface glycoconjugates is essential for osteoclastogenesis.

    PubMed

    Takahata, Masahiko; Iwasaki, Norimasa; Nakagawa, Hiroaki; Abe, Yuichiro; Watanabe, Takuya; Ito, Manabu; Majima, Tokifumi; Minami, Akio

    2007-07-01

    Sialic acid, which is located at the end of the carbohydrate moiety of cell surface glycoconjugates, is involved in many biologic responses, such as intercellular reactions and virus-cell fusion, especially in hematopoietic cells. Here we provide experimental evidence that the sialic acid of cell surface glycoconjugates has a role in osteoclast differentiation. Lectin histochemical study demonstrated the existence of both alpha (2,3)-linked-sialic acid and alpha (2,6)-linked-sialic acid in mouse bone marrow-derived macrophages and in the RAW264.7 macrophage cell line, which are osteoclast precursors. Flow cytometric analysis of surface lectin staining revealed the kinetics of these sialic acids during osteoclastogenesis: alpha (2,3)-linked-sialic acid was abundantly expressed throughout osteoclastogenesis, whereas alpha (2,6)-linked-sialic acid levels declined at the terminal stage of osteoclast differentiation. To investigate the role of sialic acid in osteoclast differentiation, we performed an osteoclastogenesis assay with or without exogenous sialidase treatment. Desialylated cells formed TRAP-positive mononuclear cells, but did not become multinuclear cells despite the normal expression of osteoclast markers such as cathepsin K, integrin beta3, and nuclear factor-ATc1. Flow cytometric analysis also demonstrated that exogenous sialidase effectively removed alpha (2,6)-linked-sialic acid, but only slightly changed the alpha (2,3)-linked-sialic acid content, suggesting that alpha (2,6)-linked-sialic acid might be involved in osteoclast differentiation. Findings from knockdown analysis using small interfering RNA oligonucleotides against alpha 2,6-sialyltransferase support this idea: alpha (2,6)-linked-sialic acid-deficient cells markedly inhibit the formation of multinuclear osteoclasts. Our findings suggest that alpha (2,6)-linked-sialic acid of cell surface glycoconjugates has a role in osteoclast differentiation, possibly via its role in the cell-cell fusion

  3. 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

  4. 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

  5. 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.

  6. Therapeutic cell engineering with surface-conjugated synthetic nanoparticles.

    PubMed

    Stephan, Matthias T; Moon, James J; Um, Soong Ho; Bershteyn, Anna; Irvine, Darrell J

    2010-09-01

    A major limitation of cell therapies is the rapid decline in viability and function of the transplanted cells. Here we describe a strategy to enhance cell therapy via the conjugation of adjuvant drug-loaded nanoparticles to the surfaces of therapeutic cells. With this method of providing sustained pseudoautocrine stimulation to donor cells, we elicited marked enhancements in tumor elimination in a model of adoptive T cell therapy for cancer. We also increased the in vivo repopulation rate of hematopoietic stem cell grafts with very low doses of adjuvant drugs that were ineffective when given systemically. This approach is a simple and generalizable strategy to augment cytoreagents while minimizing the systemic side effects of adjuvant drugs. In addition, these results suggest therapeutic cells are promising vectors for actively targeted drug delivery. PMID:20711198

  7. The role of nitric oxide in ocular surface cells.

    PubMed

    Kim, Jae Chan; Park, Gun Sic; Kim, Jin Kook; Kim, Young Myeong

    2002-06-01

    The role of nitric oxide (NO) in the ocular surface remains unknown. We investigated the conditions leading to an increase of NO generation in tear and the main sources of NO in ocular surface tissue. We evaluated the dual action (cell survival or cell death) of NO depending on its amount. We measured the concentration of nitrite plus nitrate in the tears of ocular surface diseases and examined the main source of nitric oxide synthase (NOS). When cultured human corneal fibroblast were treated with NO producing donor with or without serum, the viabilities of cells was studied. We found that the main sources of NO in ocular surface tissue were corneal epithelium, fibroblast, endothelium, and inflammatory cells. Three forms of NOS (eNOS, bNOS, and iNOS) were expressed in experimentally induced inflammation. In the fibroblast culture system, the NO donor (SNAP, S-nitroso-N-acetyl-D, L-penicillamine) prevented the death of corneal fibroblast cells caused by serum deprivation in a dose dependent manner up to 500 micrometer SNAP, but a higher dose decreased cell viability. This study suggested that NO might act as a double-edged sword in ocular surface diseases depending on the degree of inflammation related with NO concentration. PMID:12068145

  8. 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.

  9. 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. PMID:27068957

  10. 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.

  11. Development of exosome surface display technology in living human cells.

    PubMed

    Stickney, Zachary; Losacco, Joseph; McDevitt, Sophie; Zhang, Zhiwen; Lu, Biao

    2016-03-25

    Surface display technology is an emerging key player in presenting functional proteins for targeted drug delivery and therapy. Although a number of technologies exist, a desirable mammalian surface display system is lacking. Exosomes are extracellular vesicles that facilitate cell-cell communication and can be engineered as nano-shuttles for cell-specific delivery. In this study, we report the development of a novel exosome surface display technology by exploiting mammalian cell secreted nano-vesicles and their trans-membrane protein tetraspanins. By constructing a set of fluorescent reporters for both the inner and outer surface display on exosomes at two selected sites of tetraspanins, we demonstrated the successful exosomal display via gene transfection and monitoring fluorescence in vivo. We subsequently validated our system by demonstrating the expected intracellular partitioning of reporter protein into sub-cellular compartments and secretion of exosomes from human HEK293 cells. Lastly, we established the stable engineered cells to harness the ability of this robust system for continuous production, secretion, and uptake of displayed exosomes with minimal impact on human cell biology. In sum, our work paved the way for potential applications of exosome, including exosome tracking and imaging, targeted drug delivery, as well as exosome-mediated vaccine and therapy. PMID:26902116

  12. 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

  13. 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.

  14. 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

  15. 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

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

    PubMed

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

    2008-02-01

    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

  17. 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.

  18. 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

  19. Optimistic Expectancies and Cell-Mediated Immunity: The Role of Positive Affect

    PubMed Central

    Segerstrom, Suzanne C.; Sephton, Sandra E.

    2014-01-01

    Optimistic expectancies affect many psychosocial outcomes and may also predict immune system changes and health, but the nature and mechanisms of any such physiological effects have not been identified. The present study related law-school expectancies to cell-mediated immunity (CMI), examining the within- and between-person components of this relationship and affective mediators. First-year law students (N = 124) completed questionnaire measures of expectancies and affect and received delayed-type hypersensitivity skin tests at five time points. A positive relationship between optimistic expectancies and CMI occurred, in which that changes in optimism correlated with changes in CMI. Likewise, changes in optimism predicted changes in positive and, to a lesser degree, negative affect, but the relationship between optimism and immunity was partially accounted for only by positive affect. This dynamic relationship between expectancies and immunity has positive implications for psychological interventions to improve health, particularly those that increase positive affect. PMID:20424083

  20. 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. PMID:16399085

  1. 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

  2. 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. PMID:26081645

  3. An Assessment of Cell Culture Plate Surface Chemistry for in Vitro Studies of Tissue Engineering Scaffolds

    PubMed Central

    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

  4. 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

  5. Impact of nanopore morphology on cell viability on mesoporous polymer and carbon surfaces.

    PubMed

    Chavez, Vicki L; Song, Lingyan; Barua, Sutapa; Li, Xinxin; Wu, Quanyan; Zhao, Dongyuan; Rege, Kaushal; Vogt, Bryan D

    2010-08-01

    Topography at the nanoscale can lead to dramatic changes in the adhesion of cells to surfaces and their subsequent viability. For biological applications, including tissue engineering and cell-based sensing, the large internal surface area of ordered mesoporous carbons provides an opportunity for enhanced sensitivity and performance, but the mesostructure also affects the topography of the material. In this work, we probe the viability and adhesion of osteoblasts on ordered mesoporous materials with different morphologies and matrix chemistries. FDU-15 (hexagonal) and FDU-16 (cubic) films were processed at either 350 degrees C (polymeric) or 800 degrees C (carbon) to provide these different materials. For the films processed at 350 degrees C, the cell adhesion was markedly improved on the mesoporous films in comparison to a dense film analog, consistent with many reports in the literature that nanostructuring of surfaces improves the viability and adhesion of osteoblasts. Conversely, osteoblast adhesion was reduced on the carbonized surfaces processed at 800 degrees C when ordered mesopores were introduced, particularly for the cubic mesostructure (FDU-16). We attribute the decrease in cell adhesion to the propensity of the ordered mesoporous carbon films to sorb organics from aqueous solution, which could lead to removal of adhesion-promoting compounds at the film surface. These results suggest that cell viability on mesoporous polymer and carbon films can be controlled through simple changes in the pyrolysis temperature. PMID:20144750

  6. 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.

  7. Calcium phosphate surfaces promote osteogenic differentiation of mesenchymal stem cells

    PubMed Central

    Müller, Petra; Bulnheim, Ulrike; Diener, Annette; Lüthen, Frank; Teller, Marianne; Klinkenberg, Ernst-Dieter; Neumann, Hans-Georg; Nebe, Barbara; Liebold, Andreas; Steinhoff, Gustav; Rychly, Joachim

    2008-01-01

    Abstract Although studies in vivo revealed promising results in bone regeneration after implantation of scaffolds together with osteogenic progenitor cells, basic questions remain how material surfaces control the biology of mesenchymal stem cells (MSC). We used human MSC derived from bone marrow and studied the osteogenic differentiation on calcium phosphate surfaces. In osteogenic differentiation medium MSC differentiated to osteoblasts on hydroxyapatite and BONITmatrix®, a degradable xerogel composite, within 14 days. Cells revealed a higher alkaline phosphatase (ALP) activity and increased RNA expression of collagen I and osteocalcin using real-time RTPCR compared with cells on tissue culture plastic. To test whether material surface characteristics alone are able to stimulate osteogenic differentiation, MSC were cultured on the materials in expansion medium without soluble additives for osteogenic differentiation. Indeed, cells on calcium phosphate without osteogenic differentiation additives developed to osteoblasts as shown by increased ALP activity and expression of osteogenic genes, which was not the case on tissue culture plastic. Because we reasoned that the stimulating effect on osteogenesis by calcium phosphate surfaces depends on an altered cell–extracellular matrix interaction we studied the dynamic behaviour of focal adhesions using cells transfected with GFP labelled vinculin. On BONITmatrix®, an increased mobility of focal adhesions was observed compared with cells on tissue culture plastic. In conclusion, calcium phosphate surfaces are able to drive MSC to osteoblasts in the absence of osteogenic differentiation supplements in the medium. An altered dynamic behaviour of focal adhesions on calcium phosphate surfaces might be involved in the molecular mechanisms which promote osteogenic differentiation. PMID:18366455

  8. Relaxin affects cell organization and early and late stages of spermatogenesis in a coculture of rat testicular cells.

    PubMed

    Pimenta, M T; Francisco, R A R; Silva, R P; Porto, C S; Lazari, M F M

    2015-07-01

    Relaxin and its receptor RXFP1 are co-expressed in Sertoli cells, and relaxin can stimulate proliferation of Sertoli cells. In this study, we investigated a role of relaxin in spermatogenesis, using a short-term culture of testicular cells of the rat that allowed differentiation of spermatogonia to spermatids. Sertoli, germ, and peritubular myoid cells were the predominant cell types in the culture. Sertoli and germ cells expressed RXFP1. Cultures were incubated without (control) or with 0.5% fetal bovine serum (FBS) or 100 ng/mL H2 relaxin (RLN) for 2 days. Cell organization, number, and differentiation were analyzed after 2 (D2), 5 (D5) or 8 (D8) days of culturing. Although the proportion of germ cells decayed from D2 to D5, the relative contribution of HC, 1C, 2C, and 4C germ cell populations remained constant in the control group during the whole culture. RLN did not affect the proportion of germ cell populations compared with control, but increased gene and/or protein expression of the undifferentiated and differentiated spermatogonia markers PLZF and c-KIT, and of the post-meiotic marker Odf2 in D5. RLN favored organization of cells in tubule-like structures, the arrangement of myoid cells around the tubules, arrangement of c-KIT-positive spermatogonia at the basal region of the tubules, and expression of the cell junction protein β-catenin close to the plasma membrane region. Knockdown of relaxin with small interfering RNA (siRNA) reduced expression of β-catenin at the cell junctions, and shifted its expression to the nucleus. We propose that relaxin may affect spermatogenesis by modulating spermatogonial self renewal and favoring cell contact. PMID:26041439

  9. 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

  10. 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

  11. 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

  12. A rapid and selective assay for measuring cell surface hydrophobicity of brewer's yeast cells.

    PubMed

    Straver, M H; Kijne, J W

    1996-03-15

    A rapid and selective assay was developed to measure cell surface hydrophobicity of brewer's yeast cells. During this so-called magnobead assay, bottom-fermenting yeast cells adhere to paramagnetic, polystyrene-coated latex beads which can easily be removed from the cell suspension by using a (samarium-cobalt) magnet. At pH 4 center dot 5, electrostatic repulsion between yeast cells and latex beads was found to be minimal and yeast cell adhesion was predominantly based on hydrophobic interactions. The percentage of cells adhering to the beads could be calculated and provided a measure for cell surface hydrophobicity. Cell surface hydrophobicity measured by the magnobead assay was found to yield similar results, as did determination of contact angles of water droplets on a layer of yeast cells, a standard method for measuring surface hydrophobicity. However, the magnobead assay has the following advantages: (i) it is a quick and simple method, and, more significantly, (ii) hydrophobicity can be measured under physiological conditions. Use of the magnobead assay confirmed that a higher level of cell surface hydrophobicity is correlated with stronger flocculence of brewer's lager yeast cells. PMID:8904332

  13. The effect of MTAD, an endodontic irrigant, on fibroblast attachment to periodontally affected root surfaces: A SEM analysis

    PubMed Central

    Ghandi, Mostafa; Houshmand, Behzad; Nekoofar, Mohammad H.; Tabor, Rachel K.; Yadeghari, Zahra; Dummer, Paul M. H.

    2013-01-01

    Background: Root surface debridement (RSD) is necessary to create an environment suitable for reattachment of the periodontium. Root surface conditioning may aid the formation of a biocompatible surface suitable for cell reattachment. BioPure™ MTAD (mixture of Doxycycline, citric acid and a detergent) is an endodontic irrigant with antibacterial properties and the ability to remove smear layer. It was hypothesized that MTAD may be useful for root surface conditioning. The efficacy of MTAD as a conditioner was measured by examining fibroblast attachment to root surfaces. Materials and Methods: Thirty-two specimens of human teeth with advanced periodontal disease were used. The surfaces were root planed until smooth. Half of the specimens were treated with 0.9% saline and the other samples with Biopure MTAD. As a negative control group, five further samples were left unscaled with surface calculus. Human gingival fibroblast cells HGF1-PI1 were cultured and poured over the tooth specimens and incubated. After fixation, the samples were sputter-coated with gold and examined with a SEM. The morphology and number of attached, fixed viable cells were examined. The data was analysed using the Mann-Whitney-U statistical test. Results: There was no significant difference between the numbers of attached cells in the experimental group treated with MTAD and the control group treated with saline. Little or no attached cells were seen in the negative control group. Conclusion: RSD created an environment suitable for cell growth and attachment in a laboratory setting. The use of MTAD did not promote the attachment and growth of cells on the surface of human roots following RSD. PMID:23869124

  14. 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

  15. 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

  16. Biochanin A affects steroidogenesis and estrogen receptor-β expression in porcine granulosa cells.

    PubMed

    Nynca, Anna; Swigonska, Sylwia; Piasecka, Joanna; Kolomycka, Agnieszka; Kaminska, Barbara; Radziewicz-Pigiel, Marta; Gut-Nagel, Marta; Ciereszko, Renata E

    2013-10-15

    Biochanin A, similar to other isoflavones, is present in soy and soy-based food, but predominantly in red clover. Red clover extract and biochanin A were reported to affect reproductive processes as well as to demonstrate menopause relief and anticancerogenic properties. Because porcine granulosa cells provide a suitable in vitro model for studying the intracellular mechanism of phytoestrogen action in the ovary, the objective of the study was to evaluate the in vitro effects of biochanin A on the following: (1) progesterone (P4) and estradiol (E2) secretion by granulosa cells, (2) viability of the granulosa cells, and (3) mRNA and protein expression of estrogen receptors α (ERα) and β (ERβ) in the granulosa cells harvested from both medium (3-6 mm) and large (≥8 mm) porcine ovarian follicles. RIA, alamarBlue assay, reverse transcriptase-polymerase chain reaction, and immunocytochemistry were used in the study to address the objectives. Biochanin A significantly inhibited P4 and did not affect E2 secretion by porcine granulosa cells regardless of the size of follicles that served as the source of the cells. Cell viability was not affected by the treatment. Biochanin A did not alter ERα and ERβ mRNA levels in the cultured porcine granulosa cells. In contrast, this isoflavone increased (P < 0.05) the immunoexpression of ERβ in the cells from both follicle types. In summary, biochanin A, similar to genistein and daidzein, affects follicular steroidogenesis and ER expression. Its effect on ERβ protein was more intense compared with other previously examined phytoestrogens. PMID:23953692

  17. NMR spectroscopy and perfusion of mammalian cells using surface microprobes.

    PubMed

    Ehrmann, Klaus; Pataky, Kristopher; Stettler, Matthieu; Wurm, Florian Maria; Brugger, Jürgen; Besse, Pierre-André; Popovic, Radivoje

    2007-03-01

    NMR spectra of mammalian cells are taken using surface microprobes that are based on microfabricated planar coils. The surface microprobe resembles a miniaturized Petri dish commonly used in biological research. The diameter of the planar coils is 1 mm. Chinese Hamster Ovaries are immobilized in a uniform layer on the microprobe surface or patterned by an ink-jet printer in the centre of the microcoil, where the rf-field of the planar microcoil is most uniform. The acquired NMR spectra show the prevalent metabolites found in mammalian cells. The volumes of the detected samples range from 25 nL to 1 nL (or 50,000 to 1800 cells). With an extended set-up that provides fluid inlets and outlets to the microprobe, the cells can be perfused within the NMR-magnet while constantly taking NMR spectra. Perfusion of the cells opens the way to increased cell viability for long acquisitions or to analysis of the cells' response to environmental change. PMID:17330170

  18. 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

  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. PMID:23915280

  20. 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

  1. 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

  2. FAK and HAS inhibition synergistically decrease colon cancer cell viability and affect expression of critical genes.

    PubMed

    Heffler, Melissa; Golubovskaya, Vita M; Conroy, Jeffrey; Liu, Song; Wang, Dan; Cance, William G; Dunn, Kelli B

    2013-05-01

    Focal adhesion kinase (FAK), hyaluronan (HA), and hyaluronan synthase-3 (HAS3) have been implicated in cancer growth and progression. FAK inhibition with the small molecule inhibitor Y15 decreases colon cancer cell growth in vitro and in vivo. HAS3 inhibition in colon cancer cells decreases FAK expression and activation, and exogenous HA increases FAK activation. We sought to determine the genes affected by HAS and FAK inhibition and hypothesized that dual inhibition would synergistically inhibit viability. Y15 (FAK inhibitor) and the HAS inhibitor 4-methylumbelliferone (4-MU) decreased viability in a dose dependent manner; viability was further inhibited by treatment with Y15 and 4-MU in colon cancer cells. HAS inhibited cells treated with 2 μM of Y15 showed significantly decreased viability compared to HAS scrambled cells treated with the same dose (p < 0.05) demonstrating synergistic inhibition of viability with dual FAK/HAS inhibition. Microarray analysis showed more than 2-fold up- or down-regulation of 121 genes by HAS inhibition, and 696 genes by FAK inhibition (p < 0.05) and revealed 29 common genes affected by both signaling. Among the genes affected by FAK or HAS3 inhibition were genes, playing role in apoptosis, cell cycle regulation, adhesion, transcription, heatshock and WNT pathways. Thus, FAK or HAS inhibition decreases SW620 viability and affects several similar genes, which are involved in the regulation of tumor survival. Dual inhibition of FAK and HAS3 decreases viability to a greater degree than with either agent alone, and suggests that synergistic inhibition of colon cancer cell growth can result from affecting similar genetic pathways. PMID:22934709

  3. Density enhanced phosphatase-1 down-regulates urokinase receptor surface expression in confluent endothelial cells

    PubMed Central

    Brunner, Patrick M.; Heier, Patricia C.; Mihaly-Bison, Judit; Priglinger, Ute; Binder, Bernd R.

    2011-01-01

    VEGF165, the major angiogenic growth factor, is known to activate various steps in proangiogenic endothelial cell behavior, such as endothelial cell migration and invasion, or endothelial cell survival. Thereby, the urokinase-type plasminogen activator (uPA) system has been shown to play an essential role not only by its proteolytic capacities, but also by induction of intracellular signal transduction. Therefore, expression of its cell surface receptor uPAR is thought to be an essential regulatory mechanism in angiogenesis. We found that uPAR expression on the surface of confluent endothelial cells was down-regulated compared with subconfluent proliferating endothelial cells. Regulation of uPAR expression was most probably affected by extracellular signal-regulated kinase 1/2 (ERK1/2) activation, a downstream signaling event of the VEGF/VEGF-receptor system. Consistently, the receptor-like protein tyrosine phosphatase DEP-1 (density enhanced phosphatase-1/CD148), which is abundantly expressed in confluent endothelial cells, inhibited the VEGF-dependent activation of ERK1/2, leading to down-regulation of uPAR expression. Overexpression of active ERK1 rescued the DEP-1 effect on uPAR. That DEP-1 plays a biologic role in angiogenic endothelial cell behavior was demonstrated in endothelial cell migration, proliferation, and capillary-like tube formation assays in vitro. PMID:21304107

  4. 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.

  5. Polyglucosan Molecules Induce Mitochondrial Impairment and Apoptosis in Germ Cells Without Affecting the Integrity and Functionality of Sertoli Cells.

    PubMed

    Villarroel-Espíndola, Franz; Tapia, Cynthia; González-Stegmaier, Roxana; Concha, Ilona I; Slebe, Juan Carlos

    2016-10-01

    Glycogen is the main storage form of glucose; however, the accumulation of glycogen-like glucose polymers can lead to degeneration and cellular death. Previously, we reported that the accumulation of glycogen in testis of transgenic animals overexpressing a constitutively active form of glycogen synthase enhances the apoptosis of pre-meiotic male germ cells and a complete disorganization of the seminiferous tubules. Here we sought to further identify the effects of glycogen storage in cells from the seminiferous tubules and the mechanism behind the pro-apoptotic activity induced by its accumulation. Using an in vitro culture of Sertoli cells (line 42GPA9) and spermatocyte-like cells (line GC-1) expressing a superactive form of glycogen synthase or the Protein Targeting to Glycogen (PTG), we found that glycogen synthesized in both cell lines is poorly branched. In addition, the immunodetection of key molecules of apoptotic events suggests that cellular death induced by polyglucosan molecules affects GC-1 cells, but not 42GPA9 cells by mitochondrial impairment and activation of an intrinsic apoptotic pathway. Furthermore, we analyzed the effects of glycogen deposition during the establishment of an in vitro blood-testis barrier. The results using a non-permeable fluorescent molecule showed that, in conditions of over-synthesis of glycogen, 42GPA9 cells do not lose their capacity to generate an impermeable barrier and the levels of connexin43, occludin, and ZO1 proteins were not affected. These results suggest that the accumulation of polyglucosan molecules has a selective effect-triggered by the intrinsic activation of the apoptotic pathway-in germ cells without directly affecting Sertoli cells. J. Cell. Physiol. 231: 2142-2152, 2016. © 2016 Wiley Periodicals, Inc. PMID:26790645

  6. 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

  7. Proliferation, behavior, and cytokine gene expression of human umbilical vascular endothelial cells in response to different titanium surfaces.

    PubMed

    An, Na; Schedle, Andreas; Wieland, Marco; Andrukhov, Oleh; Matejka, Michael; Rausch-Fan, Xiaohui

    2010-04-01

    Success of dental implantation is initially affected by wound healing of both, hard and soft tissues. Endothelial cells (ECs) are involved as crucial cells in the angiogenesis and inflammation process of wound healing. In the present study, proliferation, mobility, cluster formation, and gene expression of angiogenesis-related molecules of human umbilical vascular endothelial cells (HUVECs) were investigated on titanium surfaces with different roughnesses: acid-etched (A), coarse-grit-blasted and acid-etched (SLA) surfaces, as well as on hydrophilic modified modA and modSLA surfaces. Cell behaviors were analyzed by proliferation assay and time-lapse microscopy, gene expression was analyzed by real time PCR. Results showed that cell proliferation, mobility, and cluster formation were highest on modA surfaces compared with all other surfaces. HUVECs moved slowly and exhibited seldom cell aggregation on SLA and modSLA surfaces during the whole observing period of 120 h. The gene expressions of the angiogenesis-related factors von Willebrand factor, thrombomodulin, endothelial cell protein C receptor, and adhesion molecules intercellular adhesion molecule-1 and E-selectin were most enhanced on modSLA surfaces. These results suggest that modA surface is optimal for proliferation and angiogenic behavior of ECs. However, modSLA surface seems to promote ECs to express angiogenesis-related factor genes, which play essential roles in controlling inflammation and revascularization of wound healing. PMID:19569217

  8. Cell surface expression and biosynthesis of epithelial Na+ channels.

    PubMed Central

    Prince, L S; Welsh, M J

    1998-01-01

    The epithelial Na+ channel (ENaC) complex is composed of three homologous subunits: alpha, beta and gamma. Mutations in ENaC subunits can increase the number of channels on the cell surface, causing a hereditary form of hypertension called Liddle's syndrome, or can decrease channel activity, causing pseudohypoaldosteronism type I, a salt-wasting disease of infancy. To investigate surface expression, we studied ENaC subunits expressed in COS-7 and HEK293 cells. Using surface biotinylation and protease sensitivity, we found that when individual ENaC subunits are expressed alone, they traffic to the cell surface. The subunits are glycosylated with high-mannose oligosaccharides, but seem to have the carbohydrate removed before they reach the cell surface. Moreover, subunits form a complex that cannot be disrupted by several non-ionic detergents. The pattern of glycosylation and detergent solubility/insolubility persists when the N-teminal and C-terminal cytoplasmic regions of ENaC are removed. With co-expression of all three ENaC subunits, the insoluble complex is the predominant species. These results show that ENaC and its family members are unique in their trafficking, biochemical characteristics and post-translational modifications. PMID:9841884

  9. Autonomous molecular cascades for evaluation of cell surfaces.

    PubMed

    Rudchenko, Maria; Taylor, Steven; Pallavi, Payal; Dechkovskaia, Alesia; Khan, Safana; Butler, Vincent P; 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. PMID:23892986

  10. An electrochemical surface plasmon resonance imaging system targeting cell analysis

    NASA Astrophysics Data System (ADS)

    Zhang, L. L.; Chen, X.; Wei, H. T.; Li, H.; Sun, J. H.; Cai, H. Y.; Chen, J. L.; Cui, D. F.

    2013-08-01

    This paper presents an electrochemical-surface plasmon resonance imaging (EC-SPRI) system, enabling the characterization of optical and electrical properties of cells, simultaneously. The developed surface plasmon resonance (SPR) imaging system was capable of imaging micro cavities with a dimension of 10 μm × 10 μm and differentiated glycerol solutions with a group of refractive indices (RIs). Furthermore, the EC-SPRI system was used to image A549 cells, suggesting corresponding RI and morphology changes during the cell death process. In the end, electrochemical and SPR methods were used in combination, recording oxidation peaks of A549 cells in the cyclic voltage curves and SPR response unit increase, simultaneously.

  11. Role of cell surface oligosaccharides of mouse mammary tumor cell lines in cancer metastasis.

    PubMed

    Zhao, Yunxue; Li, Jing; Wang, Jingjian; Xing, Yanli; Geng, Meiyu

    2007-06-01

    Malignant transformation is associated with changes in the glycosylation of cell surface proteins and lipids. In tumor cells, alterations in cellular glycosylation may play a key role in their metastatic behaviour. In the present study, we have assessed the relationship between cell surface oligosaccharides and the metastasis ability of mouse mammary tumor cell lines 67NR and 4TO7. The cell surface oligosaccharides have been analyzed using specific binding assays with some plant lectins and the metastasis ability has been studied using transwell migration and invasion assays. In addition, we investigated the role of terminal sialic acids in the metastatic potential (cell adhesion on fibronectin, cell migration and invasion) in the 4TO7 cells on treatment with neuraminidase. The cell lines used in study have different metastasis abilities in vivo - the 67NR form primary tumors, but no tumor cells are detectable in any distant tissues, while cells of the 4TO7 line are able to spread to lung. In vitro metastasis experiments have revealed higher ability of adhesion, cell migration and invasion in the 4TO7 cells than the 67NR cells. Specific lectins binding assays show that the 4TO7 cells expressed more high-mannose type, multi-antennary complex-type N-glycans, beta-1,6-GlcNAc-branching, alpha-2,6-linked sialic acids, N-acetylgalactosamine and galactosyl(beta-1,3)-N-acetylgalactosamine. Removal of sialic acids on treatment with neuraminidase decreases adhesion, but increases the migration and has shown no significant change in the invasion ability of the 4TO7 cells. The study suggests that the sialic acids are not crucial for the cell migration and invasion in the 4TO7 cells. The findings provide the new insights in understanding the role of cell surface oligosaccharides in cancer metastasis. PMID:17650582

  12. 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

  13. 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. PMID:26475923

  14. 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...

  15. 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

  16. 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

  17. 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

  18. Skewed B cell differentiation affects lymphoid organogenesis but not T cell-mediated autoimmunity.

    PubMed

    Colombo, E; Tentorio, P; Musio, S; Rajewsky, K; Pedotti, R; Casola, S; Farina, C

    2014-04-01

    B cell receptor (BCR) signalling determines B cell differentiation and may potentially alter T cell-mediated immune responses. In this study we used two transgenic strains of BCR-deficient mice expressing Epstein-Barr virus latent membrane protein (LMP)2A in B cells, where either follicular and marginal zone differentiation (D(H)LMP2A mice) or B-1 cell development (V(H)LMP2A mice) were supported, and evaluated the effects of skewed B lymphocyte differentiation on lymphoid organogenesis and T cell responses in vivo. Compared to wild-type animals, both transgenic strains displayed alterations in the composition of lymphoid organs and in the dynamics of distinct immune cell subsets following immunization with the self-antigen PLP₁₈₅₋₂₀₆. However, ex-vivo T cell proliferation to PLP₁₈₅₋₂₀₆ peptide measured in immunized D(H)LMP2A and V(H)LMP2A mice was similar to that detected in immunized control mice. Further, clinical expression of experimental autoimmune encephalitis in both LMP2A strains was identical to that of wild-type mice. In conclusion, mice with skewed B cell differentiation driven by LMP2A expression in BCR-negative B cells do not show changes in the development of a T cell mediated disease model of autoimmunity, suggesting that compensatory mechanisms support the generation of T cell responses. PMID:24325711

  19. 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.

  20. 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.

  1. Detection of cytoplasmic and surface membrane markers in cells of some human hematopoietic cell lines.

    PubMed

    Koníková, E; Babusíková, O; Kusenda, J; Glasová, M

    1992-01-01

    The cells of some human leukemia-lymphoma T cell lines (JURKAT, MOLT4), B cell lines (DAUDI, U-266) and of myeloid U-937 cell line were characterized for their surface membrane and cytoplasmic marker profiles. The usefulness of some fixation and permeabilization methods of cell membrane for detection of cytoplasmic markers by flow cytometry was studied. The methods of cell fixation in suspension were found to be more sensitive than the methods of cell fixation in smears. With the very short buffered formaldehyde-acetone (BFA) fixation used in this study an optimal penetration of the monoclonal antibodies (MoAbs) through the plasma membrane and specific binding to the appropriate structures were achieved. CD22 antigen was detected in cytoplasm but not on membrane of DAUDI cells. In another B cell line, U-266, CD22 antigen was present both in cell membrane and cytoplasm. The marker corresponding to anti-CD19 MoAb was detected in cytoplasm but was absent on membrane of U-266 cells. Furthermore, the antigen estimated by anti-CD3 MoAb could be detected intracellularly in cells of both T cell lines tested, while it was absent on cell membrane of these cells. The phenotypic study of U-937 cells showed that the majority of cells expressed myeloid associated antigens. In our study the CD14 marker detected on cell surface membrane of U-937 cells was missing in their cytoplasm. The surface antigens remained intact after BFA fixation enabling a simultaneous detection of membrane and cytoplasmic markers in double immunofluorescence studies. Through this combination of markers minor cell populations could be detected. Human hematopoietic cell lines could serve as a reliable model system for a rapid and quantitative immunodiagnosis. PMID:1491722

  2. Leukocyte Cell Surface Proteinases: Regulation of Expression, Functions, and Mechanisms of Surface Localization

    PubMed Central

    Owen, Caroline A.

    2008-01-01

    A number of proteinases are expressed on the surface of leukocytes including members of the serine, metallo-, and cysteine proteinase superfamilies. Some proteinases are anchored to the plasma membrane of leukocytes by a transmembrane domain or a glycosyl phosphatidyl inositol (GPI) anchor. Other proteinases bind with high affinity to classical receptors, or with lower affinity to integrins, proteoglycans, or other leukocyte surface molecules. Leukocyte surface levels of proteinases are regulated by: 1) cytokines, chemokines, bacterial products, and growth factors which stimulate synthesis and/or release of proteinase by cells; 2) the availability of surface binding sites for proteinases; and/or 3) internalization or shedding of surface-bound proteinases. The binding of proteinases to leukocyte surfaces serves many functions including: 1) concentrating the activity of proteinases to the immediate pericellular environment; 2) facilitating pro-enzyme activation; 3) increasing proteinase stability and retention in the extracellular space; 4) regulating leukocyte function by proteinases signaling through cell surface binding sites or other surface proteins; and 5) protecting proteinases from inhibition by extracellular proteinase inhibitors. There is strong evidence that membrane-associated proteinases on leukocytes play critical roles in wound healing, inflammation, extracellular matrix remodeling, fibrinolysis, and coagulation. This review will outline the biology of membrane-associated proteinases expressed by leukocytes and their roles in physiologic and pathologic processes. PMID:18329945

  3. 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

  4. 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

  5. Valproic Acid Affects Membrane Trafficking and Cell-Wall Integrity in Fission Yeast

    PubMed Central

    Miyatake, Makoto; Kuno, Takayoshi; Kita, Ayako; Katsura, Kosaku; Takegawa, Kaoru; Uno, Satoshi; Nabata, Toshiya; Sugiura, Reiko

    2007-01-01

    Valproic acid (VPA) is widely used to treat epilepsy and manic-depressive illness. Although VPA has been reported to exert a variety of biochemical effects, the exact mechanisms underlying its therapeutic effects remain elusive. To gain further insights into the molecular mechanisms of VPA action, a genetic screen for fission yeast mutants that show hypersensitivity to VPA was performed. One of the genes that we identified was vps45+, which encodes a member of the Sec1/Munc18 family that is implicated in membrane trafficking. Notably, several mutations affecting membrane trafficking also resulted in hypersensitivity to VPA. These include ypt3+ and ryh1+, both encoding a Rab family protein, and apm1+, encoding the μ1 subunit of the adaptor protein complex AP-1. More importantly, VPA caused vacuolar fragmentation and inhibited the glycosylation and the secretion of acid phosphatase in wild-type cells, suggesting that VPA affects membrane trafficking. Interestingly, the cell-wall-damaging agents such as micafungin or the inhibition of calcineurin dramatically enhanced the sensitivity of wild-type cells to VPA. Consistently, VPA treatment of wild-type cells enhanced their sensitivity to the cell-wall-digesting enzymes. Altogether, our results suggest that VPA affects membrane trafficking, which leads to the enhanced sensitivity to cell-wall damage in fission yeast. PMID:17287531

  6. Immunomic Screening of Cell Surface Molecules on Undifferentiated Human Dental Pulp Stem Cells.

    PubMed

    Hwang, Hyo-In; Lee, Tae-Hyung; Kang, Kyung-Jung; Ryu, Chun-Jeih; Jang, Young-Joo

    2015-08-15

    Human adult dental pulp tissue is a source of adult stem cells that have a potential to differentiate into various tissues, although the primary cell suspensions cultured from pulp tissue are mixtures of both stem cell and nonstem cell populations with heterogeneous phenotypes and various differentiation efficiencies. Therefore, cell surface protein markers on dental pulp stem cells are critical for detection and purification of stem cell populations. Yet, little is known about the cell surface molecules that are specifically associated with the undifferentiated and progenitor state of human adult dental pulp stem cells (hDPSCs). Presently, cell surface proteins expressed on hDPSCs were assessed by screening surface molecules specifically expressed on dentinogenic progenitors. Using a decoy immunization strategy, a set of monoclonal antibodies (MAbs) was generated against undifferentiated pulp progenitor cells. Forty-five hybridomas produced MAbs that interacted weakly, if at all, to differentiated pulp cells. Of these, 19 MAbs (18 IgG, 1 IgM) recognized surface molecules on undifferentiated hDPSCs. By multicolor flow cytometric analysis, 40%-60% of newly identified MAb-positive cells were demonstrated to be positive for the CD44 and CD90 mesenchymal markers. When MAb-positive cells were sorted from the heterogeneous pulp cell suspension, mineralization efficiency was increased three to five times compared with MAb-negative cells. The results suggest that the decoy immunization is an efficient method for isolation of MAbs against dentinogenic progenitors. These MAbs will be helpful for identification and enrichment of hDPSCs for efficient dentin regeneration. PMID:25919113

  7. 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. PMID:24606112

  8. 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

  9. Silver nanoparticles affect glucose metabolism in hepatoma cells through production of reactive oxygen species

    PubMed Central

    Lee, Mi Jin; Lee, Seung Jun; Yun, Su Jin; Jang, Ji-Young; Kang, Hangoo; Kim, Kyongmin; Choi, In-Hong; Park, Sun

    2016-01-01

    The silver nanoparticle (AgNP) is a candidate for anticancer therapy because of its effects on cell survival and signaling. Although numerous reports are available regarding their effect on cell death, the effect of AgNPs on metabolism is not well understood. In this study, we investigated the effect of AgNPs on glucose metabolism in hepatoma cell lines. Lactate release from both HepG2 and Huh7 cells was reduced with 5 nm AgNPs as early as 1 hour after treatment, when cell death did not occur. Treatment with 5 nm AgNPs decreased glucose consumption in HepG2 cells but not in Huh7 cells. Treatment with 5 nm AgNPs reduced nuclear factor erythroid 2-like 2 expression in both cell types without affecting its activation at the early time points after AgNPs’ treatment. Increased reactive oxygen species (ROS) production was detected 1 hour after 5 nm AgNPs’ treatment, and lactate release was restored in the presence of an ROS scavenger. Our results suggest that 5 nm AgNPs affect glucose metabolism by producing ROS. PMID:26730190

  10. 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

  11. 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.

  12. 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

  13. Transcriptional Profiling of Bipotential Embryonic Liver Cells to Identify Liver Progenitor Cell Surface Markers

    PubMed Central

    Ochsner, Scott A.; Strick-Marchand, Hélène; Qiu, Qiong; Venable, Susan; Dean, Adam; Wilde, Margaret; Weiss, Mary C.; Darlington, Gretchen J.

    2010-01-01

    The ability to purify to homogeneity a population of hepatic progenitor cells from adult liver is critical for their characterization prior to any therapeutic application. As a step in this direction, we have used a bipotential liver cell line from 14 days postcoitum mouse embryonic liver to compile a list of cell surface markers expressed specifically by liver progenitor cells. These cells, known as bipotential mouse embryonic liver (BMEL) cells, proliferate in an undifferentiated state and are capable of differentiating into hepatocyte-like and cholangiocyte-like cells in vitro. Upon transplantation, BMEL cells are capable of differentiating into hepatocytes and cholangiocytes in vivo. Microarray and Gene Ontology (GO) analysis of gene expression in the 9A1 and 14B3 BMEL cell lines grown under proliferating and differentiating conditions was used to identify cell surface markers preferentially expressed in the bipotential undifferentiated state. This analysis revealed that proliferating BMEL cells express many genes involved in cell cycle regulation, whereas differentiation of BMEL cells by cell aggregation causes a switch in gene expression to functions characteristic of mature hepatocytes. In addition, microarray data and protein analysis indicated that the Notch signaling pathway could be involved in maintaining BMEL cells in an undifferentiated stem cell state. Using GO annotation, a list of cell surface markers preferentially expressed on undifferentiated BMEL cells was generated. One marker, Cd24a, is specifically expressed on progenitor oval cells in livers of diethyl 1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate-treated animals. We therefore consider Cd24a expression a candidate molecule for purification of hepatic progenitor cells. PMID:17641245

  14. Effect of plasma surface functionalization on preosteoblast cells spreading and adhesion on a biomimetic hydroxyapatite layer formed on a titanium surface

    NASA Astrophysics Data System (ADS)

    Myung, Sung Woon; Ko, Yeong Mu; Kim, Byung Hoon

    2013-12-01

    This study examined the plasma surface modification of biomimetic hydroxyapatite (HAp) formed on a titanium (Ti) surface as well as its influence on the behavior of preosteoblast cells. Ti substrates pre-treated with a plasma-polymerized thin film rich in carboxyl groups were subjected to a biomimetic process in a simulated body fluid solution to synthesize the HAp. The HAp layer grown on Ti substrate was then coated with two types of plasma polymerized acrylic acid and allyl amine thin film. The different types of Ti substrates were characterized by attenuated total reflection Fourier transform infrared spectroscopy, energy dispersive spectroscopy and X-ray diffraction. HAp with a Ca/P ratio from 1.25 to 1.38 was obtained on the Ti substrate and hydrophilic carboxyl (sbnd COOH) and amine (sbnd NH2) functional groups were introduced to its surface. Scanning electron microscopy was used to observe the surface of the HAp coatings and the morphology of MC3T3-E1 cells. These results showed that the sbnd COOH-modified HAp surfaces promoted the cell spreading synergistically by changing the surface morphology and chemical state.sbnd NH2 modified HAp had the lowest cell spreading and proliferation compared to HAp and sbnd COOH-modified HAp. These results correspond to fluorescein analysis, which showed many more cell spreading of COOH/HAp/Ti surface compared to HAp and NH2 modified HAp. A MTT assay was used to evaluate cell proliferation. The results showed that the proliferation of MC3T3-E1 cells increased in the order of COOH/HAp/Ti > HAp/Ti > NH2/Ti > Ti, corresponding to the effect of cell spreading for 6 days. The change in morphology and the chemical surface properties of the biomaterial via plasma polymerization can affect the behavior of MC3T3-E1 cells.

  15. 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

  16. Front surface passivation of silicon solar cells with antireflection coating

    NASA Technical Reports Server (NTRS)

    Crotty, G.; Daud, T.; Kachare, R.

    1987-01-01

    It is demonstrated that the deposition and postdeposition sintering of an antireflection (AR) coating in hydrogen acts to passivate silicon solar cells. Cells with and without an SiO2 passivating layer, coated with a TiO(x)/Al2O3 AR coating, showed comparable enhancements in short-wavelength spectral response and in open-circuit voltage Voc after sintering at 400 C for 5 min in a hydrogen ambient. The improvement in Voc of cells without SiO2 is attributed to front-surface passivation by the AR coating during processing.

  17. Donor age and cell passage affects differentiation potential of murine bone marrow-derived stem cells

    PubMed Central

    Kretlow, James D; Jin, Yu-Qing; Liu, Wei; Zhang, Wen Jie; Hong, Tan-Hui; Zhou, Guangdong; Baggett, L Scott; Mikos, Antonios G; Cao, Yilin

    2008-01-01

    Background Bone marrow-derived mesenchymal stem cells (BMSCs) are a widely researched adult stem cell population capable of differentiation into various lineages. Because many promising applications of tissue engineering require cell expansion following harvest and involve the treatment of diseases and conditions found in an aging population, the effect of donor age and ex vivo handling must be understood in order to develop clinical techniques and therapeutics based on these cells. Furthermore, there currently exists little understanding as to how these two factors may be influenced by one another. Results Differences in the adipogenic, chondrogenic, and osteogenic differentiation capacity of murine MSCs harvested from donor animals of different age and number of passages of these cells were observed. Cells from younger donors adhered to tissue culture polystyrene better and proliferated in greater number than those from older animals. Chondrogenic and osteogenic potential decreased with age for each group, and adipogenic differentiation decreased only in cells from the oldest donors. Significant decreases in differentiation potentials due to passage were observed as well for osteogenesis of BMSCs from the youngest donors and chondrogenesis of the cells from the oldest donors. Conclusion Both increasing age and the number of passages have lineage dependent effects on BMSC differentiation potential. Furthermore, there is an obvious interplay between donor age and cell passage that in the future must be accounted for when developing cell-based therapies for clinical use. PMID:18957087

  18. 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

  19. 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. PMID:26030281

  20. Cell-surface GRP78 facilitates colorectal cancer cell migration and invasion.

    PubMed

    Li, Zongwei; Zhang, Lichao; Zhao, Yarui; Li, Hanqing; Xiao, Hong; Fu, Rong; Zhao, Chao; Wu, Haili; Li, Zhuoyu

    2013-05-01

    Glucose regulated protein 78 (GRP78) is predominantly located in the endoplasmic reticulum as a molecular chaperone. It has also been found on the membranes of some cancer cells, acting as a receptor for a wide variety of ligands. However, its presence on colorectal cancer (CRC) cell surface and its role in CRC metastatic progression remain elusive. Here we reported that GRP78 was predominantly present in the form of clustering aggregates on CRC cell surfaces, and its surface abundance was strongly correlated with CRC differentiation stage. Interestingly, we observed that cell-surface GRP78 had an interaction with the ECM adhesion molecule β1-integrin and was involved in cell-matrix adhesion through regulation of focal adhesion kinase (FAK). Moreover, the present data also implicated that surface GRP78 promoted the cell invasion process, and this effect was at least partly mediated through its association with uPA-uPAR protease system. Together, our data suggests that surface GRP78 promotes CRC cell migration and invasion by regulating cell-matrix adhesion and ECM degradation, which is independent of its signaling receptor function. PMID:23485528

  1. The reduction half cell in biomaterials corrosion: oxygen diffusion profiles near and cell response to polarized titanium surfaces.

    PubMed

    Gilbert, J L; Zarka, L; Chang, E; Thomas, C H

    1998-11-01

    Mechanically assisted corrosion processes can greatly increase the oxidation currents generated in passivating alloy systems like Co-Cr and titanium due to oxide film disruption. When oxide films are abraded, repassivation and ionic dissolution both occur at rates that are orders of magnitude higher than undisrupted surfaces. The excess electrons generated by these anodic processes must be consumed in corresponding reduction reactions that include the reduction of oxygen. If large enough, these reduction reactions may locally deplete the concentration of solution-dissolved oxygen and, in turn, affect cell behavior in the vicinity of the implant surface. To date, this hypothesis has not been tested. In the present study, a scanning electrochemical microscope was used to measure oxygen concentration profiles in vitro near a planar titanium electrode polarized to different voltages representative of those attainable by titanium undergoing mechanically assisted corrosion. The potentials investigated ranged from 0 mV to -1000 mV (AgCl). The oxygen concentration as a function of distance from the titanium surface was measured using a platinum-iridium microelectrode and an amperometric technique. Also, preliminary experiments were performed to assess the response of rat calvarial osteoblast-rich cells cultured for 2 h on titanium samples polarized to two different potentials (0 mV and -1000 mV versus AgCl). The results of this study indicate that oxygen concentrations near titanium surfaces are affected by sample potentials out to probe-sample distances as great as 500 microm. Within 2 microm of the surface, oxygen concentrations decreased by 15 to 25% for sample potentials between -100 and -500 mV. At potentials more negative than -600 mV, the oxygen concentration dropped rapidly to near zero by -900 mV. The cell experiments showed a statistically significant difference in the amount of cell spreading, as measured by projected cell area, between the two groups (p < 0

  2. 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

  3. Distinguishing Cancerous Liver Cells Using Surface-Enhanced Raman Spectroscopy.

    PubMed

    Huang, Jing; Liu, Shupeng; Chen, Zhenyi; Chen, Na; Pang, Fufei; Wang, Tingyun

    2016-02-01

    Raman spectroscopy has been widely used in biomedical research and clinical diagnostics. It possesses great potential for the analysis of biochemical processes in cell studies. In this article, the surface-enhanced Raman spectroscopy (SERS) of normal and cancerous liver cells incubated with SERS active substrates (gold nanoparticle) was measured using confocal Raman microspectroscopy technology. The chemical components of the cells were analyzed through statistical methods for the SERS spectrum. Both the relative intensity ratio and principal component analysis (PCA) were used for distinguishing the normal liver cells (QSG-7701) from the hepatoma cells (SMMC-7721). The relative intensity ratio of the Raman spectra peaks such as I937/I1209, I1276/I1308, I1342/I1375, and I1402/I1435 was set as the judge boundary, and the sensitivity and the specificity using PCA method were calculated. The results indicated that the surface-enhanced Raman spectrum could provide the chemical information for distinguishing the normal cells from the cancerous liver cells and demonstrated that SERS technology possessed the possible applied potential for the diagnosis of liver cancer. PMID:25432931

  4. 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.

  5. 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.

  6. Interactions of macromolecules with the mammalian cell surface.

    PubMed

    Wall, J; Ayoub, F; O'Shea, P

    1995-07-01

    The characterisation of fluoresceinphosphatidylethanolamine (FPE) as a real-time indicator of the electrostatic nature of the cell membrane surface is described. The conditions appropriate for the labelling of cell membranes and the implementation of FPE as a tool to monitor the interactions of various proteins and peptides with membranes are outlined. Some complications attributed to the erythrocyte glycocalyx are examined. In addition it is shown using neuraminidase as an example, that some types of enzyme-catalysed reactions on the cell surface may be monitored in real time. It is also shown that information concerning the binding of several proteins such as serum albumin and monoclonal antibodies are accessible with this technique. The albumin in particular is shown to exhibit a saturation of binding, the analysis of which indicates that the dissociation constant for erythrocytes was determined to be 8 microM and for lymphocytes to be almost 3 microM. On the basis of this comparison together with artificial membranes, the membrane protein components of the lymphocyte surface are implicated in the binding of albumin or the erythrocyte membrane proteins reduce the affinity of the cell surface for albumin. PMID:7593308

  7. 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...

  8. 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.

  9. Ocular surface reconstruction using stem cell and tissue engineering.

    PubMed

    Nakamura, Takahiro; Inatomi, Tsutomu; Sotozono, Chie; Koizumi, Noriko; Kinoshita, Shigeru

    2016-03-01

    Most human sensory information is gained through eyesight, and integrity of the ocular surface, including cornea and conjunctiva, is known to be indispensable for good vision. It is believed that severe damage to corneal epithelial stem cells results in devastating ocular surface disease, and many researchers and scientists have tried to reconstruct the ocular surface using medical and surgical approaches. Ocular surface reconstruction via regenerative therapy is a newly developed medical field that promises to be the next generation of therapeutic modalities, based on the use of tissue-specific stem cells to generate biological substitutes and improve tissue functions. The accomplishment of these objectives depends on three key factors: stem cells, which have highly proliferative capacities and longevities; the substrates determining the environmental niche; and growth factors that support them appropriately. This manuscript describes the diligent development of ocular surface reconstruction using tissue engineering techniques, both past and present, and discusses and validates their future use for regenerative therapy in this field. PMID:26187034

  10. 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

  11. 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

  12. Factors affecting the attachment of Treponema pallidum to mammalian cells in vitro.

    PubMed

    Wong, G H; Steiner, B; Faine, S; Graves, S

    1983-02-01

    Attachment of Treponema pallidum (Nichols) to mammalian cells is probably the first step in the pathogenesis of syphilis. It may also be important for the multiplication of T pallidum in vitro. When factors affecting the attachment of T pallidum to mammalian cells in vitro were studied significantly greater numbers of treponemes were found to attach to baby rabbit genital organ (BRGO) cells than to five other mammalian cell lines. When attached to BRGO cells T pallidum survived longer in vitro than unattached treponemes. Eagle's minimal essential medium was superior to three other culture media in increasing attachment and maintaining the survival of treponemes. Dithiothreitol (0.25-1.0 mmol/l) had no effect on the attachment of T pallidum to BRGO cells. Anaerobic conditions were superior to microaerophilic conditions, and the latter were superior to aerobic conditions for the attachment and survival of T pallidum to BRGO cells. Within the range of concentrations tested the number of treponemes attached to the BRGO cells was directly dependent on the concentrations of viable treponemes in the inoculum. Greater numbers of treponemes attached to actively metabolising BRGO cells than to quiescent or slowly growing cells. PMID:6337680

  13. JAK2 inhibitors do not affect stem cells present in the spleens of patients with myelofibrosis.

    PubMed

    Wang, Xiaoli; Ye, Fei; Tripodi, Joseph; Hu, Cing Siang; Qiu, Jiajing; Najfeld, Vesna; Novak, Jesse; Li, Yan; Rampal, Raajit; Hoffman, Ronald

    2014-11-01

    Dysregulation of Janus kinase (JAK)-signal transducer and activator of transcription signaling is central to the pathogenesis of myelofibrosis (MF). JAK2 inhibitor therapy in MF patients results in a rapid reduction of the degree of splenomegaly, yet the mechanism underlying this effect remains unknown. The in vitro treatment of splenic and peripheral blood MF CD34(+) cells with the JAK1/2/3 inhibitor, AZD1480, reduced the absolute number of CD34(+), CD34(+)CD90(+), and CD34(+)CXCR4(+) cells as well as assayable hematopoietic progenitor cells (HPCs) irrespective of the JAK2 and calreticulin mutational status. Furthermore, AZD1480 treatment resulted in only a modest reduction in the proportion of HPCs that were JAK2V617F(+) or had a chromosomal abnormality. To study the effect of the drug on MF stem cells (MF-SCs), splenic CD34(+) cells were treated with AZD1480 and transplanted into immunodeficient mice. JAK2 inhibitor therapy did not affect the degree of human cell chimerism or the proportion of malignant donor cells. These data indicate that JAK2 inhibitor treatment affects a subpopulation of MF-HPCs, while sparing another HPC subpopulation as well as MF-SCs. This pattern of activity might account for the reduction in spleen size observed with JAK2 inhibitor therapy as well as the rapid increase in spleen size observed frequently with its discontinuation. PMID:25193869

  14. JAK2 inhibitors do not affect stem cells present in the spleens of patients with myelofibrosis

    PubMed Central

    Wang, Xiaoli; Ye, Fei; Tripodi, Joseph; Hu, Cing Siang; Qiu, Jiajing; Najfeld, Vesna; Novak, Jesse; Li, Yan; Rampal, Raajit

    2014-01-01

    Dysregulation of Janus kinase (JAK)–signal transducer and activator of transcription signaling is central to the pathogenesis of myelofibrosis (MF). JAK2 inhibitor therapy in MF patients results in a rapid reduction of the degree of splenomegaly, yet the mechanism underlying this effect remains unknown. The in vitro treatment of splenic and peripheral blood MF CD34+ cells with the JAK1/2/3 inhibitor, AZD1480, reduced the absolute number of CD34+, CD34+CD90+, and CD34+CXCR4+ cells as well as assayable hematopoietic progenitor cells (HPCs) irrespective of the JAK2 and calreticulin mutational status. Furthermore, AZD1480 treatment resulted in only a modest reduction in the proportion of HPCs that were JAK2V617F+ or had a chromosomal abnormality. To study the effect of the drug on MF stem cells (MF-SCs), splenic CD34+ cells were treated with AZD1480 and transplanted into immunodeficient mice. JAK2 inhibitor therapy did not affect the degree of human cell chimerism or the proportion of malignant donor cells. These data indicate that JAK2 inhibitor treatment affects a subpopulation of MF-HPCs, while sparing another HPC subpopulation as well as MF-SCs. This pattern of activity might account for the reduction in spleen size observed with JAK2 inhibitor therapy as well as the rapid increase in spleen size observed frequently with its discontinuation. PMID:25193869

  15. Methods To Identify Aptamers against Cell Surface Biomarkers

    PubMed Central

    Cibiel, Agnes; Dupont, Daniel Miotto; Ducongé, Frédéric

    2011-01-01

    Aptamers are nucleic acid-based ligands identified through a process of molecular evolution named SELEX (Systematic Evolution of Ligands by Exponential enrichment). During the last 10-15 years, numerous aptamers have been developed specifically against targets present on or associated with the surface of human cells or infectious pathogens such as viruses, bacteria, fungi or parasites. Several of the aptamers have been described as potent probes, rivalling antibodies, for use in flow cytometry or microscopy. Some have also been used as drugs by inhibiting or activating functions of their targets in a manner similar to neutralizing or agonistic antibodies. Additionally, it is straightforward to conjugate aptamers to other agents without losing their affinity and they have successfully been used in vitro and in vivo to deliver drugs, siRNA, nanoparticles or contrast agents to target cells. Hence, aptamers identified against cell surface biomarkers represent a promising class of ligands. This review presents the different strategies of SELEX that have been developed to identify aptamers for cell surface-associated proteins as well as some of the methods that are used to study their binding on living cells.

  16. 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

  17. Formulation Changes Affect Material Properties and Cell Behavior in HA-Based Hydrogels

    PubMed Central

    Lawyer, Thomas; McIntosh, Kristen; Clavijo, Cristian; Potekhina, Lydia; Mann, Brenda K.

    2012-01-01

    To develop and optimize new scaffold materials for tissue engineering applications, it is important to understand how changes to the scaffold affect the cells that will interact with that scaffold. In this study, we used a hyaluronic acid- (HA-) based hydrogel as a synthetic extracellular matrix, containing modified HA (CMHA-S), modified gelatin (Gtn-S), and a crosslinker (PEGda). By varying the concentrations of these components, we were able to change the gelation time, enzymatic degradation, and compressive modulus of the hydrogel. These changes also affected fibroblast spreading within the hydrogels and differentially affected the proliferation and metabolic activity of fibroblasts and mesenchymal stem cells (MSCs). In particular, PEGda concentration had the greatest influence on gelation time, compressive modulus, and cell spreading. MSCs appeared to require a longer period of adjustment to the new microenvironment of the hydrogels than fibroblasts. Fibroblasts were able to proliferate in all formulations over the course of two weeks, but MSCs did not. Metabolic activity changed for each cell type during the two weeks depending on the formulation. These results highlight the importance of determining the effect of matrix composition changes on a particular cell type of interest in order to optimize the formulation for a given application. PMID:23251160

  18. 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

  19. Cell surface and secreted protein profiles of human thyroid cancer cell lines reveal distinct glycoprotein patterns.

    PubMed

    Arcinas, Arthur; Yen, Ten-Yang; Kebebew, Electron; Macher, Bruce A

    2009-08-01

    Cell surface proteins have been shown to be effective therapeutic targets. In addition, shed forms of these proteins and secreted proteins can serve as biomarkers for diseases, including cancer. Thus, identification of cell surface and secreted proteins has been a prime area of interest in the proteomics field. Most cell surface and secreted proteins are known to be glycosylated, and therefore, a proteomics strategy targeting these proteins was applied to obtain proteomic profiles from various thyroid cancer cell lines that represent the range of thyroid cancers of follicular cell origin. In this study, we oxidized the carbohydrates of secreted proteins and those on the cell surface with periodate and isolated them via covalent coupling to hydrazide resin. The glycoproteins obtained were identified from tryptic peptides and N-linked glycopeptides released from the hydrazide resin using two-dimensional liquid chromatography-tandem mass spectrometry in combination with the gas phase fractionation. Thyroid cancer cell lines derived from papillary thyroid cancer (TPC-1), follicular thyroid cancer (FTC-133), Hurthle cell carcinoma (XTC-1), and anaplastic thyroid cancer (ARO and DRO-1) were evaluated. An average of 150 glycoproteins were identified per cell line, of which more than 57% are known cell surface or secreted glycoproteins. The usefulness of the approach for identifying thyroid cancer associated biomarkers was validated by the identification of glycoproteins (e.g., CD44, galectin 3 and metalloproteinase inhibitor 1) that have been found to be useful markers for thyroid cancer. In addition to glycoproteins that are commonly expressed by all of the cell lines, we identified others that are only expressed in the more well-differentiated thyroid cancer cell lines (follicular, Hurthle cell and papillary), or by cell lines derived from undifferentiated tumors that are uniformly fatal forms of thyroid cancer (i.e., anaplastic). On the basis of the results obtained, a

  20. 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

  1. 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...

  2. 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...

  3. Factors affecting projected Arctic surface shortwave heating and albedo change in coupled climate models.

    PubMed

    Holland, Marika M; Landrum, Laura

    2015-07-13

    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

  4. 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

  5. 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

  6. Surface-bound cues in integrin-mediated cell behavior

    NASA Astrophysics Data System (ADS)

    Sanchez-Cortes, Juan-Jose

    The extracellular matrix (ECM) is a protein aggregate that supports cellular adhesion through binding with integrin cell receptors. This biological activity affects basic signaling paradigms, such as cell motility, proliferation and health. Hence, studying cell adhesion holds promise to gather basic science understanding of these interactions, and for the designs of therapies were these phenomena are uncontrolled. Unfortunately, this field has been obscured by the choice of protein adsorption as the principal assay platform preparation, rendering heterogeneous substrates that can be remodeled by cells. This thesis presents studies that used self-assembled monolayers (SAMs) as mimics of the ECM, presenting peptide and protein ligands with control of orientation and density. The examples discussed span the use of SAMs for mechanistic studies of bivalent cell adhesion proteins, engineering cell adhesion on inert monolayers with heterobifunctional ligands, a new kind of dynamic cell adhesion platform, and the combination of microcontact printing and SAMs to study cell populations. The results within these chapters are finally discussed within the context of new developments in tissue engineering, and future directions for these studies are suggested.

  7. Fatostatin Inhibits Cancer Cell Proliferation by Affecting Mitotic Microtubule Spindle Assembly and Cell Division.

    PubMed

    Gholkar, Ankur A; Cheung, Keith; Williams, Kevin J; Lo, Yu-Chen; Hamideh, Shadia A; Nnebe, Chelsea; Khuu, Cindy; Bensinger, Steven J; Torres, Jorge Z

    2016-08-12

    The sterol regulatory element-binding protein (SREBP) transcription factors have become attractive targets for pharmacological inhibition in the treatment of metabolic diseases and cancer. SREBPs are critical for the production and metabolism of lipids and cholesterol, which are essential for cellular homeostasis and cell proliferation. Fatostatin was recently discovered as a specific inhibitor of SREBP cleavage-activating protein (SCAP), which is required for SREBP activation. Fatostatin possesses antitumor properties including the inhibition of cancer cell proliferation, invasion, and migration, and it arrests cancer cells in G2/M phase. Although Fatostatin has been viewed as an antitumor agent due to its inhibition of SREBP and its effect on lipid metabolism, we show that Fatostatin's anticancer properties can also be attributed to its inhibition of cell division. We analyzed the effect of SREBP activity inhibitors including Fatostatin, PF-429242, and Betulin on the cell cycle and determined that only Fatostatin possessed antimitotic properties. Fatostatin inhibited tubulin polymerization, arrested cells in mitosis, activated the spindle assembly checkpoint, and triggered mitotic catastrophe and reduced cell viability. Thus Fatostatin's ability to inhibit SREBP activity and cell division could prove beneficial in treating aggressive types of cancers such as glioblastomas that have elevated lipid metabolism and fast proliferation rates and often develop resistance to current anticancer therapies. PMID:27378817

  8. Evaluating cell-surface expression and measuring activation of mammalian odorant receptors in heterologous cells

    PubMed Central

    Zhuang, Hanyi; Matsunami, Hiroaki

    2009-01-01

    A fundamental question in olfaction is which odorant receptors (ORs) are activated by a given odorant. A major roadblock to investigate odorant-OR relationship in mammals has been an inability to express ORs in heterologous cells suitable for screening active ligands for ORs. The discovery of the receptor-transporting protein (RTP) family has facilitated the effective cell-surface expression of ORs in heterologous cells. The establishment of a robust heterologous expression system for mammalian ORs facilitates the high-throughput “deorphanization” of these receptors by matching them to their cognate ligands. This protocol details the method used for evaluating the cell-surface expression and measuring the functional activation of ORs of transiently-expressed mammalian odorant receptors in HEK293T cells. The stages of odorant receptor cell-surface expression include cell culture preparation, transfer of cells, transfection, and immunocytochemistry/flow cytometry, odorant stimulation, and luciferase assay. This protocol can be completed in a period of 3 days from transfer of cells to cell-surface expression detection and/or measurement of functional activation. PMID:18772867

  9. Calcium accumulated by sickle cell anemia red cells does not affect their potassium (86Rb+) flux components

    SciTech Connect

    Ortiz, O.E.; Lew, V.L.; Bookchin, R.M.

    1986-03-01

    We investigate here the hypothesis that the high Ca content of sickle cell anemia (SS) red cells may produce a sustained activation of the Ca2+-dependent K+ permeability (Gardos effect) and that the particularly high Ca levels in the dense SS cell fraction rich in irreversibly sickled cells (ISCs) might account for the Na pump inhibition observed in these cells. We measured active and passive 86Rb+ influx (as a marker for K+) in density-fractionated SS cells before and after extraction of their excess Ca by exposure to the Ca ionophore (A23187) and ethylene glycol tetra-acetic acid and with or without adenosine triphosphate depletion or addition of quinine. None of these maneuvers revealed any evidence of a Ca2+-dependent K leak in SS discocytes or dense cells. Na pump inhibition in the dense SS cells was associated with normal activation by external K+ and a low Vmax that persisted after Ca extraction from the cells. These results are consistent with our recent findings that the excess Ca in these cells is compartmentalized in intracellular inside-out vesicles and unavailable as free Ca2+ to the inner membrane surface. Although the steady-state free cytoplasmic Ca2+ in oxygenated SS cells must be below the levels needed to activate the K+ channel, possible brief activation of the channels of some SS cells resulting from transient elevations of cell Ca2+ during deoxygenation-induced sickling cannot be excluded. The dense, ISC-rich SS cell fraction showed a Ca2+-independent increase in the ouabain-resistant, nonsaturable component of 86Rb+ influx that, if uncompensated by Na+ gain, could contribute to the dehydration of these cells.

  10. The inhibition of aromatase alters the mechanical and rheological properties of non-small-cell lung cancer cell lines affecting cell migration.

    PubMed

    Giannopoulou, E; Siatis, K E; Metsiou, D; Kritikou, I; Papachristou, D J; Kalofonou, M; Koutras, A; Athanassiou, G; Kalofonos, H P

    2015-02-01

    Tumor invasion and metastasis are key aspects of non-small cell lung cancer (NSCLC). During migration, cells undergo mechanical alterations. The mechanical phenotype of breast cancer cells is correlated with aromatase gene expression. We have previously shown that targeting aromatase is a promising strategy for NSCLC. The aim of this study was to examine morphological and mechanical changes of NSCLC cells, upon treatment with aromatase inhibitor and correlate their ability to migrate and invade. In vitro experiments were performed using H23 and A549 NSCLC cell lines and exemestane was used for aromatase inhibition. We demonstrated that exemestane reduced H23 cell migration and invasion and caused changes in cell morphology including increased vacuolar structures and greater pleomorphism. In addition, exemestane changed the distribution of α-tubulin in H23 and A549 cells in a way that might destabilize microtubules polymerization. These effects were associated with increased cell viscosity and decreased elastic shear modulus. Although exemestane caused similar effects in A549 cells regarding viscosity and elastic shear modulus, it did not affect A549 cell migration and caused an increase in invasion. The increased invasion was in line with vimentin perinuclear localization. Our data show that the treatment of NSCLC cells with an aromatase inhibitor not only affects cell migration and invasion but also alters the mechanical properties of the cells. It suggests that the different origin of cancer cells is associated with different morphological characteristics and mechanical behavior. PMID:25450981

  11. Analysis of cell surface alterations in Legionella pneumophila cells treated with human apolipoprotein E.

    PubMed

    Palusinska-Szysz, Marta; Zdybicka-Barabas, Agnieszka; Cytryńska, Małgorzata; Wdowiak-Wróbel, Sylwia; Chmiel, Elżbieta; Gruszecki, Wiesław I

    2015-03-01

    Binding of human apolipoprotein E (apoE) to Legionella pneumophila lipopolysaccharide was analysed at the molecular level by Fourier-transform infrared spectroscopy, thereby providing biophysical evidence for apoE-L. pneumophila lipopolysaccharide interaction. Atomic force microscopy imaging of apoE-exposed L. pneumophila cells revealed alterations in the bacterial cell surface topography and nanomechanical properties in comparison with control bacteria. The changes induced by apoE binding to lipopolysaccharide on the surface of L. pneumophila cells may participate in: (1) impeding the penetration of host cells by the bacteria; (2) suppression of pathogen intracellular growth and eventually; and (3) inhibition of the development of infection. PMID:25176171

  12. 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. PMID:25211708

  13. Sorption of heavy metals by prepared bacterial cell surfaces

    SciTech Connect

    Churchill, S.A.; Walters, J.V.; Churchill, P.F.

    1995-10-01

    Prepared biomass from two Gram-negative and one Gram-positive bacterial strains was examined for single, binary, and quaternary mixtures of polyvalent metal cation binding to cell surfaces. The biosorption of {sub 24}Cr{sup 3+}, {sub 27}Co{sup 2+}, {sub 28}Ni{sup 2+}, and {sub 29}Cu{sup 2+} for each bacterial cell type was evaluated using a batch equilibrium method. The binding of each metal by all three bacterial cells could be described by the Freundlich sorption model. The isotherm binding constants suggest that E. coli cells are the most efficient at binding copper, chromium, and nickel; and M. luteus adsorbs cobalt most efficiently. The K-values for copper bound to P. aeruginosa and E. coli are > 2-fold and > 8-fold greater, respectively, than previous reported for intact cells. The general metal-affinity series observed was Cr{sup 3+} > Cu{sup 2+} > Ni{sup 2+} > Co{sup 2+}. There was a marked lower affinity of all biosorbents for Co{sup 2+} and Ni{sup 2+}. M. luteus and E. coli had a strong preference for Co{sup 2+} over Ni{sup 2+}. Metal-binding enhancement could be ascribed to increased cell barrier surface porosity to metal-bearing solutions.

  14. TeO2 slow surface acoustic wave Bragg cell

    NASA Astrophysics Data System (ADS)

    Yao, Shi-Kay

    1991-08-01

    A newly discovered slow acoustic surface wave (SAW) on a (-110) cut TeO2 surface is reported focusing on its properties studied using a PC based numerical method. It is concluded that the slow SAW is rather tolerant to crystal surface orientation errors and has unusually deep penetration of its shear component into the thickness of substrate, about 47 wavelengths for a half amplitude point. The deep shear field is considered to be beneficial for surface acoustooptic interaction with free propagating focused laser beams. Rotation of the substrate about the z-axis makes it possible to adjust a slow SAW velocity with the potential advantage of trading acoustic velocity for less acoustic attenuation. Wider-bandwidth long signal processing time Bragg cells may be feasible utilizing this trade-off. The slow SAW device is characterized by an extremely low power consumption which might be useful for compact portable or avionics signal processing equipment applications.

  15. Foetal bovine serum-derived exosomes affect yield and phenotype of human cardiac progenitor cell culture

    PubMed Central

    Angelini, Francesco; Ionta, Vittoria; Rossi, Fabrizio; Miraldi, Fabio; Messina, Elisa; Giacomello, Alessandro

    2016-01-01

    Introduction: Cardiac progenitor cells (CPCs) represent a powerful tool in cardiac regenerative medicine. Pre-clinical studies suggest that most of the beneficial effects promoted by the injected cells are due to their paracrine activity exerted on endogenous cells and tissue. Exosomes are candidate mediators of this paracrine effects. According to their potential, many researchers have focused on characterizing exosomes derived from specific cell types, but, up until now, only few studies have analyzed the possible in vitro effects of bovine serum-derived exosomes on cell proliferation or differentiation. Methods: The aim of this study was to analyse, from a qualitative and quantitative point of view, the in vitro effects of bovine serum exosomes on human CPCs cultured either as cardiospheres or as monolayers of cardiosphere-forming cells. Results: Effects on proliferation, yield and molecular patterning were detected. We show, for the first time, that exogenous bovine exosomes support the proliferation and migration of human cardiosphere-forming cells, and that their depletion affects cardiospheres formation, in terms of size, yield and extra-cellular matrix production. Conclusion: These results stress the importance of considering differential biological effects of exogenous cell culture supplements on the final phenotype of primary human cell cultures.

  16. Kalanchoe tubiflora extract inhibits cell proliferation by affecting the mitotic apparatus

    PubMed Central

    2012-01-01

    Background Kalanchoe tubiflora (KT) is a succulent plant native to Madagascar, and is commonly used as a medicinal agent in Southern Brazil. The underlying mechanisms of tumor suppression are largely unexplored. Methods Cell viability and wound-healing were analyzed by MTT assay and scratch assay respectively. Cell cycle profiles were analyzed by FACS. Mitotic defects were analyzed by indirect immunofluoresence images. Results An n-Butanol-soluble fraction of KT (KT-NB) was able to inhibit cell proliferation. After a 48 h treatment with 6.75 μg/ml of KT, the cell viability was less than 50% of controls, and was further reduced to less than 10% at higher concentrations. KT-NB also induced an accumulation of cells in the G2/M phase of the cell cycle as well as an increased level of cells in the subG1 phase. Instead of disrupting the microtubule network of interphase cells, KT-NB reduced cell viability by inducing multipolar spindles and defects in chromosome alignment. KT-NB inhibits cell proliferation and reduces cell viability by two mechanisms that are exclusively involved with cell division: first by inducing multipolarity; second by disrupting chromosome alignment during metaphase. Conclusion KT-NB reduced cell viability by exclusively affecting formation of the proper structure of the mitotic apparatus. This is the main idea of the new generation of anti-mitotic agents. All together, KT-NB has sufficient potential to warrant further investigation as a potential new anticancer agent candidate. PMID:22963191

  17. Glycobiology of the cell surface: Its debt to cell electrophoresis 1940-65.

    PubMed

    Cook, Geoffrey M W

    2016-06-01

    This Review describes how in the period 1940-1959 cell electrophoresis (in the earlier literature often referred to as 'microelectrophoresis') was used to explore the surface chemistry of cells. Using the erythrocyte as a suitable model for the study of biological membranes, the early investigators were agreed on the presence of negatively charged groups at the surface of this cell. The contemporary dogma was that these were phosphate groups associated with phospholipids. Work in the 1960s, particularly on changes in the electrokinetic properties of erythrocytes following treatment with proteolytic enzymes, lead to the realization that the negatively charged groups at the red cell surface are predominantly due to sialic acids carried on glycoproteins. It quickly became apparent from cell electrophoresis that sialic acids have a ubiquitous presence on the surface of animal cells. This finding required that any complete model of the plasma membrane must include glycosylated molecules at the cell periphery, thus laying the foundations for the field termed 'Glycobiology of the Cell Surface'. PMID:26717803

  18. 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.

  19. DNA Replication Licensing Affects Cell Proliferation or Endoreplication in a Cell Type–Specific Manner

    PubMed Central

    del Mar Castellano, María; Boniotti, María Beatrice; Caro, Elena; Schnittger, Arp; Gutierrez, Crisanto

    2004-01-01

    In eukaryotic cells, the function of DNA replication licensing components (Cdc6 and Cdt1, among others) is crucial for cell proliferation and genome stability. However, little is known about their role in whole organisms and whether licensing control interfaces with differentiation and developmental programs. Here, we study Arabidopsis thaliana CDT1, its regulation, and the consequences of overriding licensing control. The availability of AtCDT1 is strictly regulated at two levels: (1) at the transcription level, by E2F and growth-arresting signals, and (2) posttranscriptionally, by CDK phosphorylation, a step that is required for its proteasome-mediated degradation. We also show that CDC6 and CDT1 are key targets for the coordination of cell proliferation, differentiation, and development. Indeed, altered CDT1 or CDC6 levels have cell type–specific effects in developing Arabidopsis plants: in leaf cells competent to divide, cell proliferation is stimulated, whereas in cells programmed to undergo differentiation-associated endoreplication rounds, extra endocycles are triggered. Thus, we propose that DNA replication licensing control is critical for the proper maintenance of proliferative potential, developmental programs, and morphogenetic patterns. PMID:15316110

  20. A study of compatibility between cells and biopolymeric surfaces through quantitative measurements of adhesive forces.

    PubMed

    Kim, Young Jick; Shin, Jung-Woog; Park, Ki Dong; Lee, Jin Woo; Yui, Nobuhiko; Park, Su-A; Jee, Kyoung Soo; Kim, Jeong Koo

    2003-01-01

    The mechanism of cell adhesion to biomaterials or components of the extracellular matrix is an important topic in the field of tissue engineering and related biotechnological processes. Many factors affect cell adhesion, and many biochemical and biological studies have attempted to identify their roles in the adhesion mechanism. Systematic studies of this nature require quantification of the adhesive force of a cell to identify the effect of a specific factor. However, most studies of cell adhesive force have used qualitative approaches. We propose a new technique for quantifying the force by which cells adhere to various biomaterial surfaces, which utilizes the relationship between the deflection of a cantilever beam and the required force. A micropipette was used as the cantilever beam. This technique was used to measure the attachment forces of chondrocytes seeded on three different biodegradable polymers commonly used in tissue engineering and medicine: poly epsilon-carprolactone (PCL), poly(L-lactide) (PLLA) and poly(lactic-co-glycolic acid) (PGLA, L/G = 75:25). The bond between the cells and the three polymers was evaluated using the quantified adhesive forces. The adhesive forces were also measured 8, 12, 24 h and 5 days after seeding the chondrocytes on the polymer surfaces. Results of statistical analysis showed that the cells attached to the PLLA had the strongest average attachment force for up to 24 h after seeding (P < 0.05). PMID:14870936

  1. 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.

  2. 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.

  3. 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

  4. Genomic Copy Number Variation Affecting Genes Involved in the Cell Cycle Pathway: Implications for Somatic Mosaicism

    PubMed Central

    Iourov, Ivan Y.; Vorsanova, Svetlana G.; Zelenova, Maria A.; Korostelev, Sergei A.; Yurov, Yuri B.

    2015-01-01

    Somatic genome variations (mosaicism) seem to represent a common mechanism for human intercellular/interindividual diversity in health and disease. However, origins and mechanisms of somatic mosaicism remain a matter of conjecture. Recently, it has been hypothesized that zygotic genomic variation naturally occurring in humans is likely to predispose to nonheritable genetic changes (aneuploidy) acquired during the lifetime through affecting cell cycle regulation, genome stability maintenance, and related pathways. Here, we have evaluated genomic copy number variation (CNV) in genes implicated in the cell cycle pathway (according to Kyoto Encyclopedia of Genes and Genomes/KEGG) within a cohort of patients with intellectual disability, autism, and/or epilepsy, in which the phenotype was not associated with genomic rearrangements altering this pathway. Benign CNVs affecting 20 genes of the cell cycle pathway were detected in 161 out of 255 patients (71.6%). Among them, 62 individuals exhibited >2 CNVs affecting the cell cycle pathway. Taking into account the number of individuals demonstrating CNV of these genes, a support for this hypothesis appears to be presented. Accordingly, we speculate that further studies of CNV burden across the genes implicated in related pathways might clarify whether zygotic genomic variation generates somatic mosaicism in health and disease. PMID:26421275

  5. Laser surface treatment of polyamide and NiTi alloy and the effects on mesenchymal stem cell response

    NASA Astrophysics Data System (ADS)

    Waugh, D. G.; Lawrence, J.; Shukla, P.; Chan, C.; Hussain, I.; Man, H. C.; Smith, G. C.

    2015-07-01

    Mesenchymal stem cells (MSCs) are known to play important roles in development, post-natal growth, repair, and regeneration of mesenchymal tissues. What is more, surface treatments are widely reported to affect the biomimetic nature of materials. This paper will detail, discuss and compare laser surface treatment of polyamide (Polyamide 6,6), using a 60 W CO2 laser, and NiTi alloy, using a 100 W fiber laser, and the effects of these treatments on mesenchymal stem cell response. The surface morphology and composition of the polyamide and NiTi alloy were studied by scanning electron microscopy (SEM) and X-ray photoemission spectroscopy (XPS), respectively. MSC cell morphology cell counting and viability measurements were done by employing a haemocytometer and MTT colorimetric assay. The success of enhanced adhesion and spreading of the MSCs on each of the laser surface treated samples, when compared to as-received samples, is evidenced in this work.

  6. Polar/apolar compounds induce leukemia cell differentiation by modulating cell-surface potential.

    PubMed Central

    Arcangeli, A; Carlà, M; Del Bene, M R; Becchetti, A; Wanke, E; Olivotto, M

    1993-01-01

    The mechanism of action of polar/apolar inducers of cell differentiation, such as dimethyl sulfoxide and hexamethylene-bisacetamide, is still obscure. In this paper evidence is provided that their effects on murine erythroleukemia cells are modulated by various extracellular cations as a precise function of the cation effects on membrane surface potential. The interfacial effects of the inducers were directly measured on the charged electrode, showing that both dimethyl sulfoxide and hexamethylene-bisacetamide, at the effective concentrations for cell differentiation and within the physiological range of charge density, adsorb at the charged surface and produce a potential shift. A linear correlation was found between this shift and the inducer effects on cell differentiation. Besides offering a different interpretation of the mechanism of action of the inducers, these findings indicate that surface potential has a signaling function. They may also be relevant to cancer treatments based on tumor-cell commitment to terminal differentiation. Images Fig. 1 PMID:8516337

  7. 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. PMID:25360516

  8. 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.

  9. Quantum-radiative cooling for solar cells with textured surface

    NASA Astrophysics Data System (ADS)

    Gilman, Boris; Ivanov, Igor

    2004-11-01

    Efficient technique of Quantum Radiative Cooling (QRC) of textured Solar Cells and Modules is described that is capable of Solar Module (SM) temperature reduction by 5-20C, resulting in 3-10% efficiency increase. Novel methods are based on the quantum assisted IR emission from the surface covered by either multi-layer coatings made of Si-nitride, SiO or Si oxy-nitride films or specifically designed insulating sun-transparent chamber (QRC zone) that contains Selective Emissive (SE) gas or gas mix. QRC zone is mounted on the top of Solar Module replacing existing lamination coatings. To enhance the efficiency of QRC some specific methods and fabrication procedures are proposed to form an electricly charged textured surface that provide a high Electric Field at the surface thus enhancing IR emissivity from the surface. Such procedure can be also used to form the field Induced Surface Barriers in the Si-based Solar Cells that can substitute the existing diffused Emitters resulting in significant reduction of the Cycle Time as well as prospective Fabrication Cost.

  10. Effect of tetracycline HCl on periodontally-affected human root surfaces.

    PubMed

    Trombelli, L; Scabbia, A; Zangari, F; Griselli, A; Wikesjö, U M; Calura, G

    1995-08-01

    Scanning electron microscopy was used to evaluate surface characteristics of periodontitis-exposed instrumented human cementum and dentin surfaces following topical application of tetracycline HCl (TTC). Specimens were randomly assigned to application of sterile saline for 1 minute (control); TTC (10 mg/ml) for 1 minute and 4 minutes, respectively; and TTC (100 mg/ml) for 1 minute and 4 minutes, respectively. Solutions were applied with a cotton pellet using a burnishing technique. Control specimens exhibited an amorphous irregular surface smear layer. TTC treatment of cementum for 1 minute resulted in a relatively debris-free, nonhomogeneous surface. The 4-minute application resulted in a surface exhibiting a densely fibrillar, mat-like texture. Dentin specimens conditioned for 1 minute showed a smooth surface with many tubule openings partially occluded by debris. The 4-minute treatment exposed a 3-dimensional network of intertubular and peritubular collagen fibrils. No consistent morphologic differences were observed between cementum or dentin specimens treated with TTC at concentrations of 10 and 100 mg/ml, respectively. The results suggest that topical application of TTC produces morphologic alterations of periodontitis-exposed cementum and dentin that appear related to application interval rather than concentration of the drug. PMID:7473011

  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. PMID:26454721

  12. Changes in droplet surface tension affect the observed hygroscopicity of photochemically aged biomass burning aerosol.

    PubMed

    Giordano, Michael R; Short, Daniel Z; Hosseini, Seyedehsan; Lichtenberg, William; Asa-Awuku, Akua A

    2013-10-01

    This study examines the hygroscopic and surface tension properties as a function of photochemical aging of the aerosol emissions from biomass burning. Experiments were conducted in a chamber setting at the UC-Riverside Center for Environmental Research and Technology (CE-CERT) Atmospheric Processes Lab using two biomass fuel sources, manzanita and chamise. Cloud condensation nuclei (CCN) measurements and off-line filter sample analysis were conducted. The water-soluble organic carbon content and surface tension of the extracted filter samples were measured. Surface tension information was then examined with Köhler theory analysis to calculate the hygroscopicity parameter, κ. Laboratory measurement of biomass burning smoke from two chaparral fuels is shown to depress the surface tension of water by 30% or more at organic matter concentrations relevant at droplet activation. Accounting for surface tension depression can lower the calculated κ by a factor of 2. This work provides evidence for surface tension depression in an important aerosol system and may provide closure for differing sub- and supersaturated κ measurements. PMID:23957441

  13. 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.

  14. 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.

  15. EGFRvIII does not affect radiosensitivity with or without gefitinib treatment in glioblastoma cells

    PubMed Central

    Struve, Nina; Riedel, Matthias; Schulte, Alexander; Rieckmann, Thorsten; Grob, Tobias J.; Gal, Andreas; Rothkamm, Kai; Lamszus, Katrin; Petersen, Cordula; Dikomey, Ekkehard; Kriegs, Malte

    2015-01-01

    Background Glioblastomas (GBM) are often characterized by an elevated expression of the epidermal growth factor receptor variant III (EGFRvIII). We used GBM cell lines with native EGFRvIII expression to determine whether this EGFR variant affects radiosensitivity with or without EGFR targeting. Methods Experiments were performed with GBM cell lines lacking (LN229, U87MG, U251, CAS-1) or endogenously expressing EGFRvIII (BS153, DKMG). The two latter cell lines were also used to establish sublines with a low (−) or a high proportion (+) of cells expressing EGFRvIII. EGFR signaling and the cell cycle were analyzed using Western blot and flow cytometry; cell survival was assessed by colony forming assay and double-strand break repair capacity by immunofluorescence. Results DKMG and BS153 parental cells with heterogeneous EGFRvIII expression were clearly more radiosensitive compared to other GBM cell lines without EGFRvIII expression. However, no significant difference was observed in cell proliferation, clonogenicity or radiosensitivity between the EGFRvIII− and + sublines derived from DKMG and BS153 parental cells. Expression of EGFRvIII was associated with decreased DSB repair capacity for BS153 but not for DKMG cells. The effects of EGFR targeting by gefitinib alone or in combination with irradiation were also found not to depend on EGFRvIII expression. Gefitinib was only observed to influence the proliferation of EGFRvIII− BS153 cells. Conclusion The data indicate that EGFRvIII does not alter radiosensitivity with or without anti-EGFR treatment. PMID:26418954

  16. Tumor suppressor p53 and its homologue p73alpha affect cell migration.

    PubMed

    Sablina, Anna A; Chumakov, Peter M; Kopnin, Boris P

    2003-07-25

    The p53 tumor suppressor plays a central role in the negative control of growth and survival of abnormal cells. Previously we demonstrated that in addition to these functions, p53 expression affects cell morphology and lamellar activity of the cell edge (Alexandrova, A., Ivanov, A., Chumakov, P. M., Kopnin, P. B., and Vasiliev, J. M. (2000) Oncogene 19, 5826-5830). In the present work we studied the effects of p53 and its homologue p73alpha on cell migration. We found that loss of p53 function correlated with decreased cell migration that was analyzed by in vitro wound closure test and Boyden chamber assay. The decreased motility of p53-deficient cells was observed in different cell contexts: human foreskin fibroblasts (BJ), human colon and lung carcinoma cell lines (HCT116 and H1299, respectively), as well as mouse normal fibroblasts from lung and spleen, peritoneal macrophages, and keratinocytes. On the other hand, overexpression of the p53 family member p73alpha stimulated cell migration. Changes in cell migration correlated directly with transcription activation induced by p53 or p73alpha. Noteworthy, p53 modulated cell motility in the absence of stress. The effect of p53 and p73alpha on cell migration was mediated through the activity of the phosphatidylinositol 3-kinase/Rac1 pathway. This p53/p73 function was mainly associated with some modulation of intracellular signaling rather than with stimulation of production of secreted motogenic factors. The identified novel activity of the p53 family members might be involved in regulation of embryogenesis, wound healing, or inflammatory response. PMID:12750388

  17. Cell surface markers on epithelial-Burkitt hybrid cells superinfected with Epstein-Barr virus.

    PubMed

    Glaser, R; Lenoir, G; Ferrone, S; Pellegrino, M A; de-Thé, G

    1977-07-01

    Attempts were made to superinfect two epithelial-Burkitt hybrid cell lines, designated D98/HR-1 and D98/Raji, with Epstein-Barr virus (EBV) and to investigate the expression of some cell surfacr markers including histocompatibility antigens, and the presence of B-cell markers, such as receptors for the third complement component and for monkey red blood cells. Successful superinfection of D98/HR-1 cells with EBV was made evident by the expression of early antigen and, to a lesser extent, virus capsid antigen. Only a rare D98/Raji cell was found to be positive for early antigen. The histocompatibility antigens of the parental cell lines D98, HR-1, and Raji were expressed on the surfaces of the hybrid cells. Receptors for third complement components b and d were not detected on the hybrid cells or on the D98P OR HR-1 cell lines; they were found, however, on the Raji cells, indicating that EBV receptors and complement receptors can be separated. The significance of the infection of the hybrid cells with EBV and the expression of cell surface markers is described. PMID:193641

  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. Regulatory T cells enhance mast cell production of IL-6 via surface-bound TGF-β.

    PubMed

    Ganeshan, Kirthana; Bryce, Paul J

    2012-01-15

    Mast cell degranulation is a hallmark of allergic reactions, but mast cells can also produce many cytokines that modulate immunity. Recently, CD25(+) regulatory T cells (Tregs) have been shown to inhibit mast cell degranulation and anaphylaxis, but their influence on cytokine production remained unknown. In this study, we show that, rather than inhibit, Tregs actually enhance mast cell production of IL-6. We demonstrate that, whereas inhibition of degranulation was OX40/OX40 ligand dependent, enhancement of IL-6 was due to TGF-β. Interestingly, our data demonstrate that the Treg-derived TGF-β was surface-bound, because the interaction was contact dependent, and no TGF-β was detectable in the supernatant. Soluble TGF-β1 alone was sufficient to enhance mast cell IL-6 production, and these supernatants were sufficient to promote Th17 skewing, but those from Treg-mast cell cultures were not, supporting this being surface-bound TGF-β from the Tregs. Interestingly, the augmentation of IL-6 production occurred basally or in response to innate stimuli (LPS or peptidoglycan), adaptive stimuli (IgE cross-linking by specific Ag), and cytokine activation (IL-33). We demonstrate that TGF-β led to enhanced transcription and de novo synthesis of IL-6 upon activation without affecting IL-6 storage or mRNA stability. In vivo, the adoptive transfer of Tregs inhibited mast cell-dependent anaphylaxis in a model of food allergy but promoted intestinal IL-6 and IL-17 production. Consequently, our findings establish that Tregs can exert divergent influences upon mast cells, inhibiting degranulation via OX40/OX40 ligand interactions while promoting IL-6 via TGF-β. PMID:22156492

  20. Arabidopsis FH1 Formin Affects Cotyledon Pavement Cell Shape by Modulating Cytoskeleton Dynamics.

    PubMed

    Rosero, Amparo; Oulehlová, Denisa; Stillerová, Lenka; Schiebertová, Petra; Grunt, Michal; Žárský, Viktor; Cvrčková, Fatima

    2016-03-01

    Plant cell morphogenesis involves concerted rearrangements of microtubules and actin microfilaments. We previously reported that FH1, the main Arabidopsis thaliana housekeeping Class I membrane-anchored formin, contributes to actin dynamics and microtubule stability in rhizodermis cells. Here we examine the effects of mutations affecting FH1 (At3g25500) on cell morphogenesis and above-ground organ development in seedlings, as well as on cytoskeletal organization and dynamics, using a combination of confocal and variable angle epifluorescence microscopy with a pharmacological approach. Homozygous fh1 mutants exhibited cotyledon epinasty and had larger cotyledon pavement cells with more pronounced lobes than the wild type. The pavement cell shape alterations were enhanced by expression of the fluorescent microtubule marker GFP-microtubule-associated protein 4 (MAP4). Mutant cotyledon pavement cells exhibited reduced density and increased stability of microfilament bundles, as well as enhanced dynamics of microtubules. Analogous results were also obtained upon treatments with the formin inhibitor SMIFH2 (small molecule inhibitor of formin homology 2 domains). Pavement cell shape in wild-type (wt) and fh1 plants in some situations exhibited a differential response towards anti-cytoskeletal drugs, especially the microtubule disruptor oryzalin. Our observations indicate that FH1 participates in the control of microtubule dynamics, possibly via its effects on actin, subsequently influencing cell morphogenesis and macroscopic organ development. PMID:26738547

  1. SAMM50 Affects Mitochondrial Morphology through the Association of Drp1 in Mammalian Cells.

    PubMed

    Liu, Shuo; Gao, Yali; Zhang, Cheng; Li, Han; Pan, Shiyi; Wang, Xiaoli; Du, Shiming; Deng, Zixin; Wang, Lianrong; Song, Zhiyin; Chen, Shi

    2016-05-01

    Mitochondrial fission and fusion activities are important for cell survival and function. Drp1 is a GTPase protein responsible for mitochondrial division, and SAMM50 is responsible for protein sorting and assembly. We demonstrated that SAMM50 overexpression results in Drp1-dependent mitochondrial fragmentation in HeLa cells. However, the mitochondrial fragmentation induced by SAMM50 overexpression could be reversed through co-expression with MFN2. Furthermore, SAMM50 interacts with Drp1 both in vivo and in vitro. The mitochondria in SAMM50 knockdown HeLa cells displayed a swollen phenotype, and the levels of the SAM complex and OPA1, along with the mitochondrial Drp1 levels, significantly decreased. In addition, mitochondrial inheritance was impaired in SAMM50 silenced cells. These results suggest that SAMM50 affects the Drp1-dependent mitochondrial morphology. PMID:27059175

  2. Abiotic Factors Affecting the Persistence of Avian Influenza Virus in Surface Waters of Waterfowl Habitats

    PubMed Central

    Dalton, Melinda S.; Cressler, Alan M.; Berghaus, Roy D.; Stallknecht, David E.

    2014-01-01

    Avian influenza (AI) virus can remain infectious in water for months, and virus-contaminated surface water is considered to be a source of infection within wild waterfowl populations. Previous work has characterized the effects of pH, salinity, and temperature on viral persistence in water, but most of that work was done with modified distilled water. The objective of this study was to identify the abiotic factors that influence the duration of AI virus persistence in natural surface water. Surface water samples were collected from 38 waterfowl habitats distributed across the United States. Samples were submitted to the U.S. Geological Survey National Water Quality Laboratory for chemical analysis and the University of Georgia for viral reduction time analysis. Samples were filtered with 0.22-μm filters, and the durations of persistence of three wild-bird-derived influenza A viruses within each water sample at 10, 17, and 28°C were determined. The effects of the surface water physicochemical factors on the duration of AI viral persistence in laboratory experiments were evaluated by multivariable linear regression with robust standard errors. The duration of AI virus persistence was determined to be longest in filtered surface water with a low temperature (<17°C), a neutral-to-basic pH (7.0 to 8.5), low salinity (<0.5 ppt), and a low ammonia concentration (<0.5 mg/liter). Our results also highlighted potential strain-related variation in the stability of AI virus in surface water. These results bring us closer to being able to predict the duration of AI virus persistence in surface water of waterfowl habitats. PMID:24584247

  3. 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.

  4. 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. GLIA 2016;64:1021-1033. PMID:26988125

  5. Learning beyond the Surface: Engaging the Cognitive, Affective and Spiritual Dimensions within the Curriculum

    ERIC Educational Resources Information Center

    Buchanan, Michael T.; Hyde, Brendan

    2008-01-01

    In Australia the separation of mind, body and spirit by secular society has had a significant influence on educational trends. An outcomes-based approach to education, with an emphasis on cognitive learning, has meant that the affective and spiritual dimensions of students' lives have often been understated. Classroom programs in religious…

  6. Mysterious hexagonal pyramids on the surface of Pyrobaculum cells.

    PubMed

    Rensen, Elena; Krupovic, Mart; Prangishvili, David

    2015-11-01

    In attempts to induce putative temperate viruses, we UV-irradiated cells of the hyperthermophilic archaeon Pyrobaculum oguniense. Virus replication could not be detected; however, we observed the development of pyramidal structures with 6-fold symmetry on the cell surface. The hexagonal basis of the pyramids was continuous with the cellular cytoplasmic membrane and apparently grew via the gradual expansion of the 6 triangular lateral faces, ultimately protruding through the S-layer. When the base of these isosceles triangles reached approximately 200 nm in length, the pyramids opened like flower petals. The origin and function of these mysterious nanostructures remain unknown. PMID:26115814

  7. Surface photovoltage method extended to silicon solar cell junction

    NASA Technical Reports Server (NTRS)

    Wang, E. Y.; Baraona, C. R.; Brandhorst, H. W., Jr.

    1974-01-01

    The conventional surface photovoltage (SPV) method is extended to the measurement of the minority carrier diffusion length in diffused semiconductor junctions of the type used in a silicon solar cell. The minority carrier diffusion values obtained by the SPV method agree well with those obtained by the X-ray method. Agreement within experimental error is also obtained between the minority carrier diffusion lengths in solar cell diffusion junctions and in the same materials with n-regions removed by etching, when the SPV method was used in the measurements.

  8. 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

  9. Hyaluronic acid hydrogel stiffness and oxygen tension affect cancer cell fate and endothelial sprouting

    PubMed Central

    Shen, Yu-I; Abaci, Hasan E.; Krupsi, Yoni; Weng, Lien-Chun; Burdick, Jason A.; Gerecht, Sharon

    2014-01-01

    Three-dimensional (3D) tissue culture models may recapitulate aspects of the tumorigenic microenvironment in vivo, enabling the study of cancer progression in vitro. Both hypoxia and matrix stiffness are known to regulate tumor growth. Using a modular culture system employing an acrylated hyaluronic acid (AHA) hydrogel, three hydrogel matrices with distinctive degrees of viscoelasticity — soft (78±16 Pa), medium (309± 57 Pa), and stiff (596± 73 Pa) — were generated using the same concentration of adhesion ligands. Oxygen levels within the hydrogel in atmospheric (21 %), hypoxic (5 %), and severely hypoxic (1 %) conditions were assessed with a mathematical model. HT1080 fibrosarcoma cells, encapsulated within the AHA hydrogels in high densities, generated nonuniform oxygen distributions, while lower cell densities resulted in more uniform oxygen distributions in the atmospheric and hypoxic environments. When we examined how varying viscoelasticity in atmospheric and hypoxic environments affects cell cycles and the expression of BNIP3 and BNIP3L (autophagy and apoptosis genes), and GLUT-1 (a glucose transport gene), we observed that HT1080 cells in 3D hydrogel adapted better to hypoxic conditions than those in a Petri dish, with no obvious correlation to matrix viscoelasticity, by recovering rapidly from possible autophagy/apoptotic events and alternating metabolism mechanisms. Further, we examined how HT1080 cells cultured in varying viscoelasticity and oxygen tension conditions affected endothelial sprouting and invasion. We observed that increased matrix stiffness reduced endothelial sprouting and invasion in atmospheric conditions; however, we observed increased endothelial sprouting and invasion under hypoxia at all levels of matrix stiffness with the upregulation of vascular endothelial growth factor (VEGF) and angiopoeitin-1 (ANG-1). Overall, HT1080 cells encapsulated in the AHA hydrogels under hypoxic stress recovered better from apoptosis and

  10. Prenatal and lactation nicotine exposure affects Sertoli cell and gonadotropin levels in rats.

    PubMed

    Paccola, C C; Miraglia, S M

    2016-02-01

    Nicotine is largely consumed in the world as a component of cigarettes. It can cross the placenta and reach the milk of smoking mothers. This drug induces apoptosis, affects sex hormone secretion, and leads to male infertility. To investigate the exposure to nicotine during the whole intrauterine and lactation phases in Sertoli cells, pregnant rats received nicotine (2 mg/kg per day) through osmotic minipumps. Male offsprings (30, 60, and 90 days old) had blood collected for hormonal analysis (FSH and LH) and their testes submitted for histophatological study, analysis of the frequency of the stages of seminiferous epithelium cycle, immunolabeling of apoptotic epithelial cells (TUNEL and Fas/FasL), analysis of the function and structure of Sertoli cells (respectively using transferrin and vimentin immunolabeling), and analysis of Sertoli-germ cell junctional molecule (β-catenin immunolabeling). The exposure to nicotine increased the FSH and LH plasmatic levels in adult rats. Although nicotine had not changed the number of apoptotic cells, neither in Fas nor FasL expression, it provoked an intense sloughing of epithelial cells and also altered the frequency of some stages of the seminiferous epithelium cycle. Transferrin and β-catenin expressions were not changed, but vimentin was significantly reduced in the early stages of the seminiferous cycle of the nicotine-exposed adult rats. Thus, we concluded that nicotine exposure during all gestational and lactation periods affects the structure of Sertoli cells by events causing intense germ cell sloughing observed in the tubular lumen and can compromise the fertility of the offspring. PMID:26556892

  11. Identification of genes affecting expression of phosphoglycerate kinase on the surface of group B streptococcus.

    PubMed

    Boone, Tyler J; Tyrrell, Gregory J

    2012-04-01

    Group B streptococcal phosphoglycerate kinase (GBS-PGK), a glycolytic enzyme, has previously been identified on the surface of group B streptococcus (GBS). To identify genes involved in surface expression of GBS-PGK, we performed Tn917 mutagenesis followed by quantification of PGK expressed on the GBS surface. Tn917 mutagenesis identified 4 genes (sag0966, sag0979, sag0980, and sag1003) that when disrupted, alter expression of GBS-PGK on the bacterial surface. Three of the identified genes were localized to a region of the GBS genome containing genes (sag0973-sag0977) predicted to be involved in resistance to antimicrobial peptides. One mutant isolate, designated NCS13sag1003::Tn917, was found to have increased sensitivity to the antimicrobial peptides bacitracin and nisin. In addition, all of the mutant strains assayed were found to have decreased β-hemolysis. In conclusion, we have identified genes involved in surface expression of GBS-PGK. These genes also appear to be involved in antimicrobial peptide resistance and regulate expression of the β-hemolysin. PMID:22444251

  12. 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

  13. Low proliferation and high apoptosis of osteoblastic cells on hydrophobic surface are associated with defective Ras signaling

    SciTech Connect

    Chang, Eun-Ju; Kim, Hong-Hee; Huh, Jung-Eun; Kim, In-Ae; Seung Ko, Jea; Chung, Chong-Pyoung; Kim, Hyun-Man . E-mail: hyunmkim@plaza.snu.ac.kr

    2005-02-01

    The hydrophobic (HPB) nature of most polymeric biomaterials has been a major obstacle in using those materials in vivo due to low compatibility with cells. However, there is little knowledge of the molecular detail to explain how surface hydrophobicity affects cell responses. In this study, we compared the proliferation and apoptosis of human osteoblastic MG63 cells adhered to hydrophilic (HPL) and hydrophobic surfaces. On the hydrophobic surface, less formation of focal contacts and actin stress fibers, a delay in cell cycle progression, and an increase in apoptosis were observed. By using fibroblast growth factor 1 (FGF1) as a model growth factor, we also investigated intracellular signaling pathways on hydrophilic and hydrophobic surfaces. The activation of Ras, Akt, and ERK by FGF1 was impaired in MG63 cells on the hydrophobic surface. The overexpression of constitutively active form of Ras and Akt rescued those cells from apoptosis and recovered cell cycle progression. Furthermore, their overexpression also restored the actin cytoskeletal organization on the hydrophobic surface. Finally, the proliferative, antiapoptotic, and cytoskeletal effects of constitutively active Ras in MG63 cells on the hydrophobic surface were blocked by wortmannin and PD98059 that inhibit Akt and ERK activation, respectively. Therefore, our results suggest that the activation of Ras and its downstream molecules Akt and ERK to an appropriate level is one of crucial elements in the determination of osteoblast cell responses. The Ras pathway may represent a cell biological target that should be considered for successful surface modification of biomaterials to induce adequate cell responses in the bone tissue.

  14. Azithromycin differentially affects the IL-13-induced expression profile in human bronchial epithelial cells.

    PubMed

    Mertens, Tinne C J; Hiemstra, Pieter S; Taube, Christian

    2016-08-01

    The T helper 2 (Th2) cytokine interleukin(IL)-13 is a central regulator in goblet cell metaplasia and induces the recently described Th2 gene signature consisting of periostin (POSTN), chloride channel regulator 1 (CLCA1) and serpin B2 (SERPINB2) in airway epithelial cells. This Th2 gene signature has been proposed as a biomarker to classify asthma into Th2-high and Th2-low phenotypes. Clinical studies have shown that the macrolide antibiotic azithromycin reduced clinical symptoms in neutrophilic asthma, but not in the classical Th2-mediated asthma despite the ability of azithromycin to reduce IL-13-induced mucus production. We therefore hypothesize that azithromycin differentially affects the IL-13-induced expression profile. To investigate this, we focus on IL-13-induced mucin and Th2-signature expression in human bronchial epithelial cells and how this combined expression profile is affected by azithromycin treatment. Primary bronchial epithelial cells were differentiated at air liquid interface in presence of IL-13 with or without azithromycin. Azithromycin inhibited IL-13-induced MUC5AC, which was accompanied by inhibition of IL-13-induced CLCA1 and SERPINB2 expression. In contrast, IL-13-induced expression of POSTN was further increased in cells treated with azithromycin. This indicates that azithromycin has a differential effect on the IL-13-induced Th2 gene signature. Furthermore, the ability of azithromycin to decrease IL-13-induced MUC5AC expression may be mediated by a reduction in CLCA1. PMID:27246785

  15. Dihydrolipoic but not alpha-lipoic acid affects susceptibility of eukaryotic cells to bacterial invasion.

    PubMed

    Bozhokina, Ekaterina; Khaitlina, Sofia; Gamaley, Irina

    2015-05-01

    Sensitivity of eukaryotic cells to facultative pathogens can depend on physiological state of host cells. Previously we have shown that pretreatment of HeLa cells with N-acetylcysteine (NAC) makes the cells 2-3-fold more sensitive to invasion by the wild-type Serratia grimesii and recombinant Escherichia coli expressing gene of actin-specific metalloprotease grimelysin [1]. To evaluate the impact of chemically different antioxidants, in the present work we studied the effects of α-Lipoic acid (LA) and dihydrolipoic acid (DHLA) on efficiency of S. grimesii and recombinant E. coli expressing grimelysin gene to penetrate into HeLa and CaCo cells. Similarly to the effect of NAC, pretreatment of HeLa and CaCo cells with 0.6 or 1.25 mM DHLA increased the entry of grimelysin producing bacteria by a factor of 2.5 and 3 for the wild-type S. grimesii and recombinant E. coli, respectively. In contrast, pretreatment of the cells with 0.6 or 1.25 mM LA did not affect the bacteria uptake. The increased invasion of HeLa and CaCo cells correlated with the enhanced expression of E-cadherin and β-catenin genes, whereas expression of these genes in the LA-treated cells was not changed. Comparison of these results suggests that it is sulfhydryl group of DHLA that promotes efficient modification of cell properties assisting bacterial uptake. We assume that the NAC- and DHLA-induced stimulation of the E-cadherin-catenin pathway contributes to the increased internalization of the grimelysin producing bacteria within transformed cells. PMID:25817791

  16. Chitosan and Chitin Hexamers affect expansion and differentiation of mesenchymal stem cells differently.

    PubMed

    Lieder, Ramona; Thormodsson, Finnbogi; Ng, C-H; Einarsson, Jon M; Gislason, Johannes; Petersen, Petur H; Sigurjonsson, Olafur E

    2012-11-01

    Chitooligosaccharides are of interest as potential drugs due to their bioactivity and water solubility. We compared the effect of acetylated and deacetylated chitooligomers (Hexamers) on short-term expansion (7 days) and osteogenic differentiation of bone-marrow derived, human mesenchymal stem cells in terms of gene expression, cytokine secretion and quality of osteogenic differentiation. We show that chitooligomers affect hMSC gene expression and cytokine secretion, but not mineralization. The effect of chitooligomers was shown to be dependent on the acetylation degree, with significantly stronger effects when cells are stimulated with chitin-derived Hexamers (N-Acetyl Chitohexaose) than with Chitosan Hexamers (Chitohexaose). PMID:22790025

  17. 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

  18. Cell surface nucleolin antagonist causes endothelial cell apoptosis and normalization of tumor vasculature.

    PubMed

    Fogal, Valentina; Sugahara, Kazuki N; Ruoslahti, Erkki; Christian, Sven

    2009-01-01

    Nucleolin is specifically transported to the surface of proliferating endothelial cells in vitro and in vivo. In contrast to its well defined functions in the nucleus and cytoplasm, the function of cell surface nucleolin is poorly defined. We have previously identified the nucleolin-binding antibody NCL3 that specifically binds to cell surface nucleolin on angiogenic blood vessels in vivo and is internalized into the cell. Here, we show that NCL3 inhibits endothelial tube formation in vitro as well as angiogenesis in the matrigel plaque assay and subcutaneous tumor models in vivo. Intriguingly, the specific targeting of proliferating endothelial cells by NCL3 in subcutaneous tumor models leads to the normalization of the tumor vasculature and as a result to an increase in tumor oxygenation. Treatment of endothelial cells with anti-nucleolin antibody NCL3 leads to a decrease of mRNA levels of the anti-apoptotic molecule Bcl-2 and as a consequence induces endothelial cell apoptosis as evidenced by PARP cleavage. These data reveal a novel mode of action for anti-angiogenic therapy and identify cell surface nucleolin as a novel target for combinatorial chemotherapy. PMID:19225898

  19. Cytoplasmic and surface membrane phenotypic markers in cells of B cell chronic lymphocytic leukemia.

    PubMed

    Koníková, E; Babusíková, O; Mesárosová, A; Kusenda, J; Glasová, M

    1994-01-01

    Peripheral blood cells of twenty-six patients with B cell chronic lymphocytic leukemia (B-CLL) were characterized for their surface membrane and cytoplasmic marker profiles using flow cytometry and fluorescence microscopy. According to surface membrane marker analysis three distinct immunophenotypic subgroups of B-CLL were identified: group I (SIg+, MR+, CD5+, B Ag+, T Ag-; 19 cases), group II (SIg+, MR+, CD5+, B Ag+, TAg+; 3 cases), group III (SIg-, MR+, CD5+, B Ag+, T Ag-; 4 cases). Cells from all patients were positive for the CD19 antigen and at least one of other B cell antigens. Cells from all patients expressed also CD5 and HLA-DR antigens and formed mouse rosettes (MR). Great heterogeneity was found in the membrane and cytoplasmic marking by anti-CD22 MoAb. In four of 23 patients tested, CD22 antigen was expressed in the cytoplasm of CLL cells while it was absent on surface membrane of these cells. This finding was discussed from the point of certain cell heterogeneity in the followed B-CLL cases. Cytoplasmic immunoglobulin (CyIg) detection showed to be very important especially in group III of followed B-CLL cases with undetectable surface immunoglobulins (SIg). Cytoplasmic antigens and immunoglobulin determinations are useful in phenotyping every B-CLL patient, as well as in the immunological study of different maturation stages of B lymphocytes. PMID:8208317

  20. Interaction of Human Tumor Viruses with Host Cell Surface Receptors and Cell Entry

    PubMed Central

    Schäfer, Georgia; Blumenthal, Melissa J.; Katz, Arieh A.

    2015-01-01

    Currently, seven viruses, namely Epstein-Barr virus (EBV), Kaposi’s sarcoma-associated herpes virus (KSHV), high-risk human papillomaviruses (HPVs), Merkel cell polyomavirus (MCPyV), hepatitis B virus (HBV), hepatitis C virus (HCV) and human T cell lymphotropic virus type 1 (HTLV-1), have been described to be consistently associated with different types of human cancer. These oncogenic viruses belong to distinct viral families, display diverse cell tropism and cause different malignancies. A key to their pathogenicity is attachment to the host cell and entry in order to replicate and complete their life cycle. Interaction with the host cell during viral entry is characterized by a sequence of events, involving viral envelope and/or capsid molecules as well as cellular entry factors that are critical in target cell recognition, thereby determining cell tropism. Most oncogenic viruses initially attach to cell surface heparan sulfate proteoglycans, followed by conformational change and transfer of the viral particle to secondary high-affinity cell- and virus-specific receptors. This review summarizes the current knowledge of the host cell surface factors and molecular mechanisms underlying oncogenic virus binding and uptake by their cognate host cell(s) with the aim to provide a concise overview of potential target molecules for prevention and/or treatment of oncogenic virus infection. PMID:26008702

  1. Cholesterol level affects surface charge of lipid membranes in saline solution

    PubMed Central

    Magarkar, Aniket; Dhawan, Vivek; Kallinteri, Paraskevi; Viitala, Tapani; Elmowafy, Mohammed; Róg, Tomasz; Bunker, Alex

    2014-01-01

    Cholesterol is an important component of all biological membranes as well as drug delivery liposomes. We show here that increasing the level of cholesterol in a phospholipid membrane decreases surface charge in the physiological environment. Through molecular dynamics simulation we have shown that increasing the level of cholesterol decreases Na+ ion binding. Complementary experimental ζ – potential measurements have shown a decreased ζ – potential with increasing cholesterol content, indicative of reduced surface charge. Both experiments and simulations have been carried out on both saturated 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and monounsaturated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes. This result is particularly important because membrane surface charge plays an important role in the interactions of biomembranes with peripheral membrane proteins and drug delivery liposomes with the immune system. PMID:24845659

  2. Surface and subsurface geologic risk factors to ground water affecting brownfield redevelopment potential.

    PubMed

    Kaufman, Martin M; Murray, Kent S; Rogers, Daniel T

    2003-01-01

    A model is created for assessing the redevelopment potential of brownfields. The model is derived from a space and time conceptual framework that identifies and measures the surface and subsurface risk factors present at brownfield sites. The model then combines these factors with a contamination extent multiplier at each site to create an index of redevelopment potential. Results from the application of the model within an urbanized watershed demonstrate clear differences between the redevelopment potential present within five different near-surface geologic units, with those units containing clay being less vulnerable to subsurface contamination. With and without the extent multiplier, the total risk present at the brownfield sites within all the geologic units is also strongly correlated to the actual costs of remediation. Thus, computing the total surface and subsurface risk within a watershed can help guide the remediation efforts at broad geographic scales, and prioritize the locations for redevelopment. PMID:12708672

  3. Enhancing Cell therapies from the Outside In: Cell Surface Engineering Using Synthetic Nanomaterials

    PubMed Central

    Stephan, Matthias T.; Irvine, Darrell J.

    2011-01-01

    Therapeutic treatments based on the injection of living cells are in clinical use and preclinical development for diseases ranging from cancer to cardiovascular disease to diabetes. To enhance the function of therapeutic cells, a variety of chemical and materials science strategies are being developed that engineer the surface of therapeutic cells with new molecules, artificial receptors, and multifunctional nanomaterials, synthetically endowing donor cells with new properties and functions. These approaches offer a powerful complement to traditional genetic engineering strategies for enhancing the function of living cells. PMID:21826117

  4. Enhancing Cell therapies from the Outside In: Cell Surface Engineering Using Synthetic Nanomaterials.

    PubMed

    Stephan, Matthias T; Irvine, Darrell J

    2011-06-01

    Therapeutic treatments based on the injection of living cells are in clinical use and preclinical development for diseases ranging from cancer to cardiovascular disease to diabetes. To enhance the function of therapeutic cells, a variety of chemical and materials science strategies are being developed that engineer the surface of therapeutic cells with new molecules, artificial receptors, and multifunctional nanomaterials, synthetically endowing donor cells with new properties and functions. These approaches offer a powerful complement to traditional genetic engineering strategies for enhancing the function of living cells. PMID:21826117

  5. How the extinction of extragalactic background light affects surface photometry of galaxies, groups and clusters

    NASA Astrophysics Data System (ADS)

    Zackrisson, E.; Micheva, G.; Östlin, G.

    2009-08-01

    The faint regions of galaxies, groups and clusters hold important clues about how these objects formed, and surface photometry at optical and near-infrared wavelengths represents a powerful tool for studying such structures. Here, we identify a hitherto unrecognized problem with this technique, related to how the night sky flux is typically measured and subtracted from astronomical images. While most of the sky flux comes from