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Sample records for cell surface resulting

  1. Ocular Surface Reconstruction with Cultivated Limbal Epithelial Cells in Limbal Stem Cell Deficiency: One-year Follow-up Results

    Directory of Open Access Journals (Sweden)

    İsmet Durak

    2012-05-01

    Full Text Available Pur po se: To evaluate the 1-year follow-up results of cultivated limbal epithelial cell (CLEC transplantation in unilateral limbal stem cell deficiency (LSCD. Ma te ri al and Met hod: One-year follow-up results of five unilateral LSCD patients who had undergone CLEC transplantation were evaluated. Parameters for this evaluation were: fluorescein staining of ocular surface, corneal vascularization and status of epithelium with slit lamp, and visual acuity. 1.5-mm limbal biopsy was performed from the superior limbus of the healthy eyes, broke into two equal pieces, expanded on human amniotic membrane (hAM and inserts for 14 days until getting 20 mm in size. CLECs on hAMs were used directly, and cells on inserts were usedafter detachment procedure. The symblepharon and pannus tissues were removed, superficial keratectomy was performed. CLEC on hAMs were transplanted with the epithelial side up onto the bare corneal stroma, sutured to the conjunctiva with 10-0 nylon sutures. Free CLEC layer from insert was placed on hAM as a second layer, additional hAM was used as a protective layer all over other tissues. Re sults: Median age was 44.4 years (14-71. The etiology was chemical burn in all patients. Median duration of symptoms was 10 years (2-18, median follow-up period was 12.6 (12-12.5 months. Preoperative best corrected visual acuities (BCVA were light perception in three patients, counting fingers at 50 cm in one patient and 3/10 in one patient. Visions were improved in all patients. Postoperative BCVA 12 months after the surgery were between counting fingers at 3 meters to 6/10. There was a temporary hemorrhage between the two layers of hAMs in one patient at the early postoperative period. Peripheral corneal vascularization has occurred in three patients, in patient corneal vascularization has reached to the paracentral area. Dis cus si on: CLEC transplantation is an efficient treatment option for unilateral LSCD in mid-long term. (Turk J

  2. Results of 1 MeV proton irradiation of front and back surfaces of silicon solar cells

    Science.gov (United States)

    Anspaugh, B. E.; Kachare, R.; Weizer, V. G.

    1987-01-01

    Several silicon solar cells with and without back surface fields (BSF), having thicknesses of 200 microns and 63 microns were irradiated with 1 MeV protons having fluences between 1 times 10 to the 10th power and 1 times 10 to the 12th power p/square cm. The irradiation was performed using both normal and isotropic incidence on the front as well as back surfaces of the solar cells. The results of the back surface irradiations are analyzed using a model in which irradiation induced defects across the high-low (BSF) junction are considered. It is concluded that degradation of the high-low junction is responsible for the severe performance loss in thinner cells when irradiated from the rear.

  3. Elucidating the Kinetics of Expression and Immune Cell Infiltration Resulting from Plasmid Gene Delivery Enhanced by Surface Dermal Electroporation

    Directory of Open Access Journals (Sweden)

    Kate E. Broderick

    2013-08-01

    Full Text Available The skin is an attractive tissue for vaccination in a clinical setting due to the accessibility of the target, the ease of monitoring and most importantly the immune competent nature of the dermal tissue. While skin electroporation offers an exciting and novel future methodology for the delivery of DNA vaccines in the clinic, little is known about the actual mechanism of the approach and the elucidation of the resulting immune responses. To further understand the mechanism of this platform, the expression kinetics and localization of a reporter plasmid delivered via a surface dermal electroporation (SEP device as well as the effect that this treatment would have on the resident immune cells in that tissue was investigated. Initially a time course (day 0 to day 21 of enhanced gene delivery with electroporation (EP was performed to observe the localization of green fluorescent protein (GFP expression and the kinetics of its appearance as well as clearance. Using gross imaging, GFP expression was not detected on the surface of the skin until 8 h post treatment. However, histological analysis by fluorescent microscopy revealed GFP positive cells as early as 1 h after plasmid delivery and electroporation. Peak GFP expression was observed at 24 h and the expression was maintained in skin for up to seven days. Using an antibody specific for a keratinocyte cell surface marker, reporter gene positive keratinocytes in the epidermis were identified. H&E staining of treated skin sections demonstrated an influx of monocytes and granulocytes at the EP site starting at 4 h and persisting up to day 14 post treatment. Immunological staining revealed a significant migration of lymphocytic cells to the EP site, congregating around cells expressing the delivered antigen. In conclusion, this study provides insights into the expression kinetics following EP enhanced DNA delivery targeting the dermal space. These findings may have implications in the future to design

  4. Targeting surface nucleolin with multivalent HB-19 and related Nucant pseudopeptides results in distinct inhibitory mechanisms depending on the malignant tumor cell type

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    Hovanessian Ara G

    2011-08-01

    Full Text Available Abstract Background Nucleolin expressed at the cell surface is a binding protein for a variety of ligands implicated in tumorigenesis and angiogenesis. By using a specific antagonist that binds the C-terminal RGG domain of nucleolin, the HB-19 pseudopeptide, we recently reported that targeting surface nucleolin with HB-19 suppresses progression of established human breast tumor cells in the athymic nude mice, and delays development of spontaneous melanoma in the RET transgenic mice. Methods By the capacity of HB-19 to bind stably surface nucleolin, we purified and identified nucleolin partners at the cell surface. HB-19 and related multivalent Nucant pseudopeptides, that present pentavalently or hexavalently the tripeptide Lysψ(CH2N-Pro-Arg, were then used to show that targeting surface nucleolin results in distinct inhibitory mechanisms on breast, prostate, colon carcinoma and leukemia cells. Results Surface nucleolin exists in a 500-kDa protein complex including several other proteins, which we identified by microsequencing as two Wnt related proteins, Ku86 autoantigen, signal recognition particle subunits SRP68/72, the receptor for complement component gC1q-R, and ribosomal proteins S4/S6. Interestingly, some of the surface-nucleolin associated proteins are implicated in cell signaling, tumor cell adhesion, migration, invasion, cell death, autoimmunity, and bacterial infections. Surface nucleolin in the 500-kDa complex is highly stable. Surface nucleolin antagonists, HB-19 and related multivalent Nucant pseudopeptides, exert distinct inhibitory mechanisms depending on the malignant tumor cell type. For example, in epithelial tumor cells they inhibit cell adhesion or spreading and induce reversion of the malignant phenotype (BMC cancer 2010, 10:325 while in leukemia cells they trigger a rapid cell death associated with DNA fragmentation. The fact that these pseudopeptides do not cause cell death in epithelial tumor cells indicates that cell

  5. Angiotensin I-converting enzyme Gln1069Arg mutation impairs trafficking to the cell surface resulting in selective denaturation of the C-domain.

    Directory of Open Access Journals (Sweden)

    Sergei M Danilov

    Full Text Available BACKGROUND: Angiotensin-converting enzyme (ACE; Kininase II; CD143 hydrolyzes small peptides such as angiotensin I, bradykinin, substance P, LH-RH and several others and thus plays a key role in blood pressure regulation and vascular remodeling. Complete absence of ACE in humans leads to renal tubular dysgenesis (RTD, a severe disorder of renal tubule development characterized by persistent fetal anuria and perinatal death. METHODOLOGY/PRINCIPAL FINDINGS: Patient with RTD in Lisbon, Portugal, maintained by peritoneal dialysis since birth, was found to have a homozygous substitution of Arg for Glu at position 1069 in the C-terminal domain of ACE (Q1069R resulting in absence of plasma ACE activity; both parents and a brother who are heterozygous carriers of this mutation had exactly half-normal plasma ACE activity compared to healthy individuals. We hypothesized that the Q1069R substitution impaired ACE trafficking to the cell surface and led to accumulation of catalytically inactive ACE in the cell cytoplasm. CHO cells expressing wild-type (WT vs. Q1069R-ACE demonstrated the mutant accumulates intracellularly and also that it is significantly degraded by intracellular proteases. Q1069R-ACE retained catalytic and immunological characteristics of WT-ACE N domain whereas it had 10-20% of the nativity of the WT-ACE C domain. A combination of chemical (sodium butyrate or pharmacological (ACE inhibitor chaperones with proteasome inhibitors (MG 132 or bortezomib significantly restored trafficking of Q1069R-ACE to the cell surface and increased ACE activity in the cell culture media 4-fold. CONCLUSIONS/SIGNIFICANCE: Homozygous Q1069R substitution results in an ACE trafficking and processing defect which can be rescued, at least in cell culture, by a combination of chaperones and proteasome inhibitors. Further studies are required to determine whether similar treatment of individuals with this ACE mutation would provide therapeutic benefits such as

  6. Elucidating the Kinetics of Expression and Immune Cell Infiltration Resulting from Plasmid Gene Delivery Enhanced by Surface Dermal Electroporation

    OpenAIRE

    Broderick, Kate E; Sardesai, Niranjan Y.; Smith, Trevor R. F.; Kiosses, William B.; Christine L. Knott; Gleb Kichaev; Amante, Dinah H.; Mendoza, Janess M

    2013-01-01

    The skin is an attractive tissue for vaccination in a clinical setting due to the accessibility of the target, the ease of monitoring and most importantly the immune competent nature of the dermal tissue. While skin electroporation offers an exciting and novel future methodology for the delivery of DNA vaccines in the clinic, little is known about the actual mechanism of the approach and the elucidation of the resulting immune responses. To further understand the mechanism of this platform, t...

  7. Cells behaviors and genotoxicity on topological surface

    Energy Technology Data Exchange (ETDEWEB)

    Yang, N.; Yang, M.K.; Bi, S.X. [Tianjin Key Laboratory of Fiber Modification and Functional Fiber, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin, 300387 (China); Chen, L., E-mail: chenlis@tjpu.edu.cn [Tianjin Key Laboratory of Fiber Modification and Functional Fiber, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin, 300387 (China); Zhu, Z.Y.; Gao, Y.T.; Du, Z. [Tianjin Key Laboratory of Artificial Cell, Tianjin Third Central Hospital, Tianjin, 300170 (China)

    2013-08-01

    To investigate different cells behaviors and genotoxicity, which were driven by specific microenvironments, three patterned surfaces (pillars, wide grooves and narrow grooves) and one smooth surface were prepared by template-based technique. Vinculin is a membrane-cytoskeletal protein in focal adhesion plaques and associates with cell–cell and cell–matrix junctions, which can promote cell adhesion and spreading. The immunofluorescence staining of vinculin revealed that the narrow grooves patterned substrate was favorable for L929 cell adhesion. For cell multiplication, the narrow grooves surface was fitted for the proliferation of L929, L02 and MSC cells, the pillars surface was only in favor of L929 cells to proliferate during 7 days of cell cultivation. Cell genetic toxicity was evaluated by cellular micronuclei test (MNT). The results indicated that topological surfaces were more suitable for L929 cells to proliferate and maintain the stability of genome. On the contrary, the narrow grooves surface induced higher micronuclei ratio of L02 and MSC cells than other surfaces. With the comprehensive results of cell multiplication and MNT, it was concluded that the wide grooves surface was best fitted for L02 cells to proliferate and have less DNA damages, and the smooth surface was optimum for the research of MSC cells in vitro. - Highlights: • Different cells behaviors on microstructure surfaces were discussed in this paper. • The expression of cell protein of Vinculin was studied in this research. • Cellular micronuclei test was applied to evaluate cells' genotoxicity. • Cell genotoxicity was first studied in the research field of topological surfaces.

  8. Controlled surface chemistries and quantitative cell response

    Science.gov (United States)

    Plant, Anne L.

    2002-03-01

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

  9. Role of T3 surface molecules in human T-cell activation: T3-dependent activation results in an increase in cytoplasmic free calcium.

    OpenAIRE

    Weiss, A; Imboden, J; Shoback, D; Stobo, J.

    1984-01-01

    The human T-cell leukemia, Jurkat, and a T3-negative mutant of Jurkat (S.5) were used to study the role of T3 in human T-cell activation. Incubation of Jurkat with phytohemagglutinin (PHA) resulted in the production of interleukin 2, which was markedly increased by the addition of phorbol 12-myristate 13-acetate (PMA). Antibodies reactive with T3 could activate Jurkat only if added together with PMA. However, S.5 cells failed to produce interleukin 2 in response to PHA and produced 1/16th the...

  10. Homestake surface-underground scintillators: Initial results

    International Nuclear Information System (INIS)

    The first 70 tons of the 140-ton Large Area Scintillation Detector (LASD) have been operating since Jan. 1985 at a depth of 4850 ft. (4200 m.w.e.) in the Homestake Gold Mine, Lead, S.D. A total of 4 x 10(4) high-energy muons (E sub mu is approx. 2.7 TeV at the surface) have been detected. The remainder of the detector is scheduled to be in operation by the Fall of 1985. In addition, a surface air shower array is under construction. The first 27 surface counters, spaced out over an area of 270' x 500', began running in June, 1985. The LASD performance, the potential of the combined shower array and underground muon experiment for detecting point sources, and the initial results of a search for periodic emission from Cygnus X-3 are discussed

  11. The Plant Cell Surface

    Institute of Scientific and Technical Information of China (English)

    Anne-Mie C.Emons; Kurt V.Fagerstedt

    2010-01-01

    @@ Multicellular organization and tissue construction has evolved along essentially different lines in plants and animals. Since plants do not run away, but are anchored in the soil, their tissues are more or less firm and stiff. This strength stems from the cell walls, which encase the fragile cytoplasm, and protect it.

  12. The cell-surface interaction.

    Science.gov (United States)

    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

  13. Cassini-Huygens results on Titan's surface

    Institute of Scientific and Technical Information of China (English)

    Athena Coustenis; Mathieu Hirtzig

    2009-01-01

    Our understanding of Titan, Saturn's largest satellite, has recently been consid-erably enhanced, thanks to the Cassini-Huygens mission. Since the Saturn Orbit Injection in July 2004, the probe has been harvesting new insights of the Kronian system. In par-ticular, this mission orchestrated a climax on January 14, 2005 with the descent of the Huygens probe into Titan's thick atmosphere. The orbiter and the lander have provided us with picturesque views of extraterrestrial landscapes, new in composition but reassuringly Earth-like in shape. Thus, Saturn's largest satellite displays chains of mountains, fields of dark and damp dunes, lakes and possibly geologic activity. As on Earth, landscapes on Titan are eroded and modeled by some alien hydrology: dendritic systems, hydrocarbon lakes, and methane clouds imply periods of heavy rainfalls, even though rain was never observed directly. Titan's surface also proved to be geologically active - today or in the recent past - given the small number of impact craters listed to date, as well as a few possible cryovolcanic features. We attempt hereafter a synthesis of the most significant results of the Cassini-Huygens endeavor, with emphasis on the surface.

  14. Using response surface methodology (RSM) to obtain preliminary results from Generation IV super critical water reactor (SCWR) fuel and lattice cell scoping

    International Nuclear Information System (INIS)

    This work illustrates the use of the Response Surface Methodology (RSM) to scope the design of a Super Critical Water Reactor (SCWR). Design parameters such as fuel fissile content, reactor lattice pitch, pressure tube thickness and fuel channel insulator thickness and porosity are examined. Changes in these parameters are evaluated for their effect on three operational responses: fuel exit burnup, coolant void reactivity and peak linear element rating. RSM is a fast and accurate scoping tool with which a response surface can be presented as a function of any two factors, while other factors are held fixed. (author)

  15. Femtosecond fabricated surfaces for cell biology

    Science.gov (United States)

    Day, Daniel; Gu, Min

    2010-08-01

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

  16. The Cell Surface Proteome of Human Mesenchymal Stromal Cells

    OpenAIRE

    Christian Niehage; Charlotte Steenblock; Theresia Pursche; Martin Bornhäuser; Denis Corbeil; Bernard Hoflack

    2011-01-01

    BACKGROUND: Multipotent human mesenchymal stromal cells (hMSCs) are considered as promising biological tools for regenerative medicine. Their antibody-based isolation relies on the identification of reliable cell surface markers. METHODOLOGY/PRINCIPAL FINDINGS: To obtain a comprehensive view of the cell surface proteome of bone marrow-derived hMSCs, we have developed an analytical pipeline relying on cell surface biotinylation of intact cells using cell impermeable, cleavable sulfo-NHS-SS-bio...

  17. Infection with an H2 recombinant herpes simplex virus vector results in expression of MHC class I antigens on the surfaces of human neuroblastoma cells in vitro and mouse sensory neurons in vivo.

    Science.gov (United States)

    Abendroth, A; Simmons, A; Efstathiou, S; Pereira, R A

    2000-10-01

    The majority of neurons in herpes simplex virus (HSV)-infected murine sensory ganglia are transiently induced to express MHC-I antigens at the cell surface, whereas only a minority are themselves productively infected. The aim of the current work was to determine whether MHC-I antigens can be expressed on the surfaces of infected neurons in addition to their uninfected neighbours. To address this aim a recombinant HSV type 1 strain, S-130, was used to deliver a mouse H2K(d) gene, under control of the HCMV IE-1 promoter/enhancer, into human neuroblastoma cells in vitro and mouse primary sensory neurons in vivo. S-130 expressed H2K(d) antigens on the surfaces of IMR-32 cells, a human neuroblastoma cell line that expresses very low levels of MHC-I constitutively. In K562 cells, which do not express MHC-I constitutively, H2K(d) and beta(2)-microglobulin (beta(2)m) were shown to be co-expressed at the cell surface following S-130 infection. This observation was taken as evidence that class I heavy chain (alphaC) molecules encoded by the expression cassette in the HSV genome were transported to the cell surface as stable complexes with beta(2)m. Significantly, after introduction of S-130 into flank skin, H2K(d) antigens were detected on the surfaces of primary sensory neurons in ganglia innervating the inoculation site. Our data show that HSV-infected murine primary sensory neurons and human neuroblastoma cells are capable of expressing cell-surface MHC-I molecules encoded by a transgene. From this, we infer that up-regulation of alphaC expression is, in principle, sufficient to overcome potential impediments to neuronal cell surface expression of MHC-I complexes.

  18. Functions of proteoglycans at the cell surface

    DEFF Research Database (Denmark)

    Höök, M; Woods, A; Johansson, S;

    1986-01-01

    Proteoglycans (primarily heparan sulphate proteoglycans) are found at the surface of most adherent eukaryotic cells. Earlier studies suggest that these molecules can be associated with the cell surface principally by two different mechanisms. Proteoglycans may occur as membrane-intercalated glyco......Proteoglycans (primarily heparan sulphate proteoglycans) are found at the surface of most adherent eukaryotic cells. Earlier studies suggest that these molecules can be associated with the cell surface principally by two different mechanisms. Proteoglycans may occur as membrane......-intercalated glycoproteins, where the core protein of the proteoglycan is anchored in the lipid interior of the plasma membrane, or they may be bound via the polysaccharide components of the molecule to specific anchoring proteins present at the cell surface. A number of functions have been proposed for cell surface...

  19. Probe microscopy: Scanning below the cell surface

    Science.gov (United States)

    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.

  20. Programming Surface Chemistry with Engineered Cells.

    Science.gov (United States)

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

    2016-09-16

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

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

    Science.gov (United States)

    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

  2. Basic Surface Properties of Mononuclear Cells from Didelphis marsupialis

    Directory of Open Access Journals (Sweden)

    Nacife Valéria Pereira

    1998-01-01

    Full Text Available 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°and 40.8°, 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.

  3. The pancreatic beta cell surface proteome

    OpenAIRE

    Stützer, I.; Esterházy, D.; Stoffel, M.

    2012-01-01

    The pancreatic beta cell is responsible for maintaining normoglycaemia by secreting an appropriate amount of insulin according to blood glucose levels. The accurate sensing of the beta cell extracellular environment is therefore crucial to this endocrine function and is transmitted via its cell surface proteome. Various surface proteins that mediate or affect beta cell endocrine function have been identified, including growth factor and cytokine receptors, transporters, ion channels and prote...

  4. Surface Functionalization for Protein and Cell Patterning

    Science.gov (United States)

    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.

  5. Severe disruption of the cytoskeleton and immunologically relevant surface molecules in a human macrophageal cell line in microgravity-Results of an in vitro experiment on board of the Shenzhou-8 space mission

    Science.gov (United States)

    Paulsen, Katrin; Tauber, Svantje; Goelz, Nadine; Simmet, Dana Michaela; Engeli, Stephanie; Birlem, Maria; Dumrese, Claudia; Karer, Anissja; Hunziker, Sandra; Biskup, Josefine; Konopasek, Shalimar; Suh, Durie; Hürlimann, Eva; Signer, Christoph; Wang, Anna; Sang, Chen; Grote, Karl-Heinrich; Zhuang, Fengyuan; Ullrich, Oliver

    2014-01-01

    During spaceflight the immune system is one of the most affected systems of the human body. During the SIMBOX (Science in Microgravity Box) mission on Shenzhou-8, we investigated microgravity-associated long-term alterations in macrophageal cells, the most important effector cells of the immune system. We analyzed the effect of long-term microgravity on the cytoskeleton and immunologically relevant surface molecules. Human U937 cells were differentiated into a macrophageal phenotype and exposed to microgravity or 1g on a reference centrifuge on-orbit for 5 days. After on-orbit fixation, the samples were analyzed with immunocytochemical staining and confocal microscopy after landing. The unmanned Shenzhou-8 spacecraft was launched on board a Long March 2F (CZ-2F) rocket from the Jiuquan Satellite Launch Center (JSLC) and landed after a 17-day-mission. We found a severely disturbed actin cytoskeleton, disorganized tubulin and distinctly reduced expression of CD18, CD36 and MHC-II after the 5 days in microgravity. The disturbed cytoskeleton, the loss of surface receptors for bacteria recognition, the activation of T lymphocytes, the loss of an important scavenger receptor and of antigen-presenting molecules could represent a dysfunctional macrophage phenotype. This phenotype in microgravity would be not capable of migrating or recognizing and attacking pathogens, and it would no longer activate the specific immune system, which could be investigated in functional assays. Obviously, the results have to be interpreted with caution as the model system has some limitations and due to numerous technical and biological restrictions (e.g. 23 °C and no CO2 supply during in-flight incubation). All parameter were carefully pre-tested on ground. Therefore, the experiment could be adapted to the experimental conditions available on Shenzhou-8.

  6. The cell surface of Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    1984-01-01

    Full Text Available The cell surface of trypanosomatids is formed by the plasma membrane and a layer of sub-pellicular microtubules which are connected to the plasma membrane. The plasma membrane is composed by proteins, lipids and carbohydrates which form the glycocalix. In this paper we will review briefly aspects related to the organization of the cell surface of Trypanosoma cruzi.

  7. Radioimmunoassay to quantitatively measure cell surface immunoglobulins

    International Nuclear Information System (INIS)

    A radioimmunoassay techniques developed to quantitatively measure the presence of immunoglobulins on the surface of cells, is described. The amount of immunoglobulins found on different tumor cells varied from 200 to 1140 ng/106 cells. Determination of immunoglobulins on the peripheral lymphocytes obtained from different cancer patients varied between 340 to 1040 ng/106 cells. Cultured tumor cells, on the other hand, were found to contain negligible quantities of human IgG

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

    Directory of Open Access Journals (Sweden)

    Damaris Bausch-Fluck

    Full Text Available 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.

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

    Science.gov (United States)

    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

  10. Cell-surface remodelling during mammalian erythropoiesis.

    Science.gov (United States)

    Wraith, D C; Chesterton, C J

    1982-10-15

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

  11. Nanostructuring of Solar Cell Surfaces

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Schmidt, Michael Stenbæk

    schemes such as atomic layer deposition (ALD) of Al2O3. ALD Al2O3 passivation on black Si yields surface recombination velocity (SRV) below 80 cm/s and implied open-circuit voltage (iVOC) of 680 mV. Surface recombination velocity of 20 cm/s and implied open-circuit voltage of 695 mV is obtained for black...

  12. How cells tiptoe on adhesive surfaces before sticking

    CERN Document Server

    Pierres, Anne; Touchard, Dominique; Bongrand, Pierre

    2008-01-01

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

  13. Cell behaviour on chemically microstructured surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Magnani, Agnese; Priamo, Alfredo; Pasqui, Daniela; Barbucci, Rolando

    2003-03-03

    Micropatterned surfaces with different chemical topographies were synthesised in order to investigate the influence of surface chemistry and topography on cell behaviour. The microstructured materials were synthesised by photoimmobilising natural Hyaluronan (Hyal) and its sulphated derivative (HyalS), both adequately functionalised with a photorective moiety, on glass substrates. Four different grating patterns (10, 25, 50 and 100 {mu}m) were used to pattern the hyaluronan. The micropatterned samples were analysed by Secondary Ions Mass Spectrometry, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy to investigate the chemistry and the topography of the surfaces. The spectroscopic and microscopic analysis of the microstructured surfaces revealed that the photoimmobilisation process was successful, demonstrating that the photomask patterns were well reproduced on the sample surface. The influence of chemical topographies on the cell behaviour was then analysed. Human and 3T3 fibroblasts, bovine aortic and human (HGTFN line) endothelial cells were used and their behaviour on the micropatterned surfaces was analysed in terms of adhesion, proliferation, locomotion and orientation. Both chemical and topographical controls were found to be important for cell guidance. By decreasing the stripe dimensions, a more fusiform shape of cell was observed. At the same time, the cell locomotion and orientation parallel to the structure increased. However, differences in cell behaviour were detected according to both cell type and micropattern dimensions.

  14. FABRICATION AND BIOCOMPATIBILITY OF CELL OUTER MEMBRANE MIMETIC SURFACES

    Institute of Scientific and Technical Information of China (English)

    Ming-ming Zong; Yong-kuan Gong

    2011-01-01

    The surface design used for improving biocompatibility is one of the most important issues for the fabrication of medical devices. For mimicking the ideal surface structure of cell outer membrane, a large number of polymers bearing phosphorylcholine (PC) groups have been employed to modify the surfaces of biomaterials and medical devices. It has been demonstrated that the biocompatibility of the modified materials whose surface is required to interact with a living organism has been obviously improved by introducing PC groups. In this review, the fabrication strategies of cell outer membrane mimetic surfaces and their resulted biocompatibilities were summarized.

  15. Smooth Muscle Cell Functionality on Collagen Immobilized Polycaprolactone Nanowire Surfaces

    Directory of Open Access Journals (Sweden)

    Victoria Leszczak

    2014-05-01

    Full Text Available Inhibition of smooth muscle cell (SMC proliferation and preservation of a differentiated state are important aspects in the management, avoidance and progression of vascular diseases. An understanding of the interaction between SMCs and the biomaterial involved is essential for a successful implant. In this study, we have developed collagen immobilized nanostructured surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of human aortic SMCs. The nanowire surfaces were fabricated from polycaprolactone and were immobilized with collagen. The objective of this study is to reveal how SMCs interact with collagen immobilized nanostructures. The results indicate significantly higher cellular adhesion on nanostructured and collagen immobilized surfaces; however, SMCs on nanostructured surfaces exhibit a more elongated phenotype. The reduction of MTT was significantly lower on nanowire (NW and collagen immobilized NW (colNW surfaces, suggesting that SMCs on nanostructured surfaces may be differentiated and slowly dividing. Scanning electron microscopy results reveal that SMCs on nanostructured surfaces are more elongated and that cells are interacting with the nano-features on the surface. After providing differentiation cues, heavy chain myosin and calponin, specific to a contractile SMC phenotype, are upregulated on collagen immobilized surfaces. These results suggest that nanotopography affects cell adhesion, proliferation, as well as cell elongation, while collagen immobilized surfaces greatly affect cell differentiation.

  16. Evaluating Surface Flux Results from CERES-FLASHFlux

    Science.gov (United States)

    Wilber, A. C.; Stackhouse, P. W.; Kratz, D. P.; Gupta, S. K.; Sawaengphokhai, P.

    2015-12-01

    The Fast Longwave and Shortwave Radiative Flux (FLASHFlux) data product was developed to provide a rapid release version of the Clouds and Earth's Radiant Energy System (CERES) results, which could be made available to the research and applications communities within one week of the satellite observations by exchanging some accuracy for speed of processing. TOA and surface flux products are provided for each CERES footprint (Single Scanner Footprint - SSF) and also time integrated and spatially averaged (TISA) to provide global daily averaged quantities. Despite the use of the most recently available calibration coefficients and operational inputs that are different from CERES formal climate quality data products, FLASHFlux has been found to provide results that compare very favorably with the CERES results. The TISA results from the FLASHFlux highly parameterized models are compared to the surface fluxes from CERES-EBAF, which uses a radiative transfer model, for the time period when both products are available. The FLASHFlux surface data products also have been found to give accurate surface flux results when compared to ground measurements. We present validation of both footprint-level and time-space averaged surface fluxes against ground measurements. Validation is done for both longwave (LW) and shortwave (SW) surface fluxes. The surface radiation measurements for land and island sites are collected from multiple networks, including the Baseline Surface Radiation Network (BSRN), Atmospheric Radiation Measurement (ARM). In the US, the NOAA SURFRAD network provides surface flux data products within a day of measurement and these are optimal for FLASHFlux validation. Ocean buoy measurements are from Woods Hole Oceanographic Institute (WHOI). Overall bias for the SSF downward LW flux has been found to be about 6 Wm-2. For SW the bias is about 3 Wm-2. Clear and cloudy sky conditions will be evaluated separately. Validation is also examined by surface type.

  17. Functional dynamics of cell surface membrane proteins

    Science.gov (United States)

    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.

  18. Adhesion of cells to polystyrene surfaces

    OpenAIRE

    1983-01-01

    The surface treatment of polystyrene, which is required to make polystyrene suitable for cell adhesion and spreading, was investigated. Examination of surfaces treated with sulfuric acid or various oxidizing agents using (a) x-ray photoelectron and attenuated total reflection spectroscopy and (b) measurement of surface carboxyl-, hydroxyl-, and sulfur-containing groups by various radiochemical methods showed that sulfuric acid produces an insignificant number of sulfonic acid groups on polyst...

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

    Science.gov (United States)

    Wyroba, E

    1978-08-01

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

  20. Nanotomography of Cell Surfaces with Evanescent Fields

    Directory of Open Access Journals (Sweden)

    Michael Wagner

    2008-01-01

    Full Text Available The technique of variable-angle total internal reflection fluorescence microscopy (TIRFM and its application to nanotomography of cell surfaces are described. Present applications include (1 3D imaging of chromosomes in their metaphase to demonstrate axial resolution in the nanometre range, (2 measurements of cell-substrate topology, which upon cholesterol depletion shows some loosening of cell-substrate contacts, and (3 measurements of cell topology upon photodynamic therapy (PDT, which demonstrate cell swelling and maintenance of focal contacts. The potential of the method for in vitro diagnostics, but also some requirements and limitations are discussed.

  1. Cell Adhesion on Surface-Functionalized Magnesium.

    Science.gov (United States)

    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

  2. Nanocrystalline diamond surfaces for adhesion and growth of primary neurons, conflicting results and rational explanation

    Directory of Open Access Journals (Sweden)

    Silviya Mikhailovna Ojovan

    2014-06-01

    Full Text Available Using a variety of proliferating cell types, it was shown that the surface of nanocrystalline-diamond (NCD provides a permissive substrate for cell adhesion and development without the need of complex chemical functionalization prior to cell seeding. In an extensive series of experiments we found that, unlike proliferating cells, post-mitotic primary neurons do not adhere to bare NCD surfaces when cultured in defined medium. These observations raise questions on the potential use of bare NCD as an interfacing layer for neuronal devices. Nevertheless, we also found that classical chemical functionalization methods render the hostile bare NCD surfaces with adhesive properties that match those of classically functionalized substrates used extensively in biomedical research and applications. Based on the results, we propose a mechanism that accounts for the conflicting results; which on one hand claim that un-functionalized NCD provides a permissive substrate for cell adhesion and growth, while other reports demonstrate the opposite.

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Science.gov (United States)

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

    2016-12-01

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

  5. Augmented dry cooling surface test program: analysis and experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Parry, H.L.; MacGowan, L.J.; Kreid, D.K.; Wiles, L.E.; Faletti, D.W.; Johnson, B.M.

    1979-09-01

    Experiments were performed to assess the operating characteristics and potential performance of water-augmented dry cooling systems. The work was aimed at evaluating a deluged air-cooled HOETERV plate fin heat exchanger surface proposed for integrated dry/wet cooling systems and using test results to guide the development of a predictive analytical model. In the process, all-dry performance data were obtained for the HOETERV surface as well as for two Curtiss-Wright chipped fin surfaces. The dry heat transfer data indicate that a slotted Curtiss-Wright surface slightly outperforms the HOETERV and nonslotted Curtiss-Wright surfaces based on heat rejection rate per unit of fan power. However, all three surfaces are so close in performance that other factors, such as surface cost and piping and mounting costs, will probably determine which surface is preferred at a given installation. Comparisons of deluged HOETERV performance with dry HOETERV and Curtiss-Wright performance under prototypic conditions have established that deluging can provide considerable heat rejection enhancement, particularly at low ITD and low air humidity. A deluged HOETERV core operating at a 115/sup 0/F primary fluid temperature in 105/sup 0/F air at 10% relative humidity can reject over 7 times as much heat as a dry HOETERV core operating under the same conditions at the same air-side pressure drop. Deluged tests were performed to evaluate the effect of airflow rate, deluge flow rate and core tilt angle on performance. Both increased airflow and increased deluge flow increase both heat rejection rate and required fan power. Optimal airflow rate will thus be determined for a given location by the competing costs of heat exchanger surface area versus fan operation. Changes in core tilt angle from vertical to 16/sup 0/ from vertical have a negligible effect on performance.

  6. Surface cell immobilization within perfluoroalkoxy microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Stojkovič, Gorazd; Krivec, Matic [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Vesel, Alenka [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Marinšek, Marjan [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Žnidaršič-Plazl, Polona, E-mail: polona.znidarsic@fkkt.uni-lj.si [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia)

    2014-11-30

    Graphical abstract: - Highlights: • A very efficient approach for immobilization of cells into microreactors is presented. • It is applicable to various materials, including PFA and cyclic olefin (co)polymers. • It was used to immobilize different prokaryotic and eukaryotic microbes. • Cells were immobilized on the surface in high density and showed good stability. • Mechanisms of APTES interactions with target materials are proposed. - Abstract: 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{sup ®} and Topas{sup ®}.

  7. The cell surface proteome of human mesenchymal stromal cells.

    Directory of Open Access Journals (Sweden)

    Christian Niehage

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

  8. Adhesion defective BHK cell mutant has cell surface heparan sulfate proteoglycan of altered properties

    DEFF Research Database (Denmark)

    Couchman, J R; Austria, R; Woods, A;

    1988-01-01

    sulfation, reduced affinity for fibronectin and decreased half-life on the cell surface when compared to the normal counterpart. Our conclusions based on this data are that these altered properties may, in part, account for the adhesion defect in the ricin-resistant mutant. Whether this results from......In the light of accumulating data that implicate cell surface heparan sulfate proteoglycans (HSPGs) with a role in cell interactions with extracellular matrix molecules such as fibronectin, we have compared the properties of these molecules in wild-type BHK cells and an adhesion-defective ricin......-resistant mutant (RicR14). Our results showed that the mutant, unlike BHK cells, cannot form focal adhesions when adherent to planar substrates in the presence of serum. Furthermore, while both cell lines possess similar amounts of cell surface HSPG with hydrophobic properties, that of RicR14 cells had decreased...

  9. The homestake surface-underground scintillators: Initial results

    Science.gov (United States)

    Cherry, M. L.; Corbato, S.; Daily, T.; Fenyves, E. J.; Kieda, D.; Lande, K.; Lee, C. K.

    1986-01-01

    The first 70 tons of the 140-ton Large Area Scintillation Detector (LASD) have been operating since Jan. 1985 at a depth of 4850 ft. (4200 m.w.e.) in the Homestake Gold Mine, Lead, S.D. A total of 4 x 10(4) high-energy muons (E sub mu is approx. 2.7 TeV at the surface) have been detected. The remainder of the detector is scheduled to be in operation by the Fall of 1985. In addition, a surface air shower array is under construction. The first 27 surface counters, spaced out over an area of 270' x 500', began running in June, 1985. The LASD performance, the potential of the combined shower array and underground muon experiment for detecting point sources, and the initial results of a search for periodic emission from Cygnus X-3 are discussed.

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

    Science.gov (United States)

    Chen, Jianbo

    ingrowth, pore coverage, cell adhesion and proliferation was observed to increase with decreasing pore size. It was found that fiber geometries provided guidance for cell spreading along the fiber directions. However, the larger gaps in fiber geometries made pore bridging difficult. Finally, this dissertation presents an in vivo study of the combined effects of laser microgrooving and RGD-coating on the osseointegration of implanted Ti-6Al-4V pins. Both histological and biomechanical results show that the combination of laser microgrooving and RGD-coating results in improved osseointegration over the control surfaces. All the above findings have important implications for future orthopedic and dental implant design.

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

    Science.gov (United States)

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

    2008-12-01

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

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

    Science.gov (United States)

    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 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. Engineering novel cell surface chemistry for selective tumor cell targeting

    Energy Technology Data Exchange (ETDEWEB)

    Bertozzi, C.R. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley National Lab., CA (United States)

    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.

  14. Effect of hydroxyapatite surface morphology on cell adhesion.

    Science.gov (United States)

    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

  15. Biomimetic surface modification of titanium surfaces for early cell capture by advanced electrospinning

    International Nuclear Information System (INIS)

    The time required for osseointegration with a metal implant having a smooth surface ranges from three to six months. We hypothesized that biomimetic coating surfaces with poly(lactic-co-glycolic acid) (PLGA)/collagen fibers and nano-hydroxyapatite (n-HA) on the implant would enhance the adhesion of mesenchymal stem cells. Therefore, this surface modification of dental and bone implants might enhance the process of osseointegration. In this study, we coated PLGA or PLGA/collagen (50:50 w/w ratio) fiber on Ti disks by modified electrospinning for 5 s to 2 min; after that, we further deposited n-HA on the fibers. PLGA fibers of fiber diameter 0.957 ± 0.357 µm had a contact angle of 9.9 ± 0.3° and PLGA/collagen fibers of fiber diameter 0.378 ± 0.068 µm had a contact angle of 0°. Upon n-HA incorporation, all the fibers had a contact angle of 0° owing to the hydrophilic nature of n-HA biomolecule. The cell attachment efficiency was tested on all the scaffolds for different intervals of time (10, 20, 30 and 60 min). The alkaline phosphatase activity, cell proliferation and mineralization were analyzed on all the implant surfaces on days 7, 14 and 21. Results of the cell adhesion study indicated that the cell adhesion was maximum on the implant surface coated with PLGA/collagen fibers deposited with n-HA compared to the other scaffolds. Within a short span of 60 min, 75% of the cells adhered onto the mineralized PLGA/collagen fibers. Similarly by day 21, the rate of cell proliferation was significantly higher (p ≤ 0.05) on the mineralized PLGA/collagen fibers owing to enhanced cell adhesion on these fibers. This enhanced initial cell adhesion favored higher cell proliferation, differentiation and mineralization on the implant surface coated with mineralized PLGA/collagen fibers.

  16. The ZEPLIN III Detector; Results from Surface Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Sumner, T.J. [Blackett Laboratory, Imperial College London (United Kingdom); Akimov, D.Yu. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Alner, G.J. [Particle Physics Department, Rutherford Appleton Laboratory, Chilton (United Kingdom); Araujo, H.M.; Bewick, A. [Blackett Laboratory, Imperial College London (United Kingdom); Bungau, C.; Burenkov, A.A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Carson, M.J.; Chagani, H. [Physics and Astronomy Department, University of Sheffield (United Kingdom); Chepel, V. [LIP-Coimbra and Department of Physics of the University of Coimbra (Portugal); Cline, D. [Department of Physics and Astronomy, University of California, Los Angeles (United States); Davidge, D. [Blackett Laboratory, Imperial College London (United Kingdom); Daw, E. [Physics and Astronomy Department, University of Sheffield (United Kingdom); Dawson, J. [Blackett Laboratory, Imperial College London (United Kingdom); Durkin, T. [Particle Physics Department, Rutherford Appleton Laboratory, Chilton (United Kingdom); Edwards, B.; Gamble, T. [Physics and Astronomy Department, University of Sheffield (United Kingdom); Chag, C. [School of Physics, University of Edinburgh (United Kingdom); Hollingworth, R.J. [Physics and Astronomy Department, University of Sheffield (United Kingdom); Howard, A.S. [Blackett Laboratory, Imperial College London (United Kingdom)] (and others)

    2007-11-15

    ZEPLIN-III is a direct dark-matter search instrument using liquid xenon as a target. Both the scintillation light and the ionisation charge are measured.The instrument has been built and it is currently being testing in a surface laboratory. We present results from some of the initial testing, including design thermal control system verification, photomultiplier calibration (including spectral measurements with 60 keV photons from {sup 241}Am) and two-phase operation showing simultaneous measurement of scintillation and charge and position reconstruction.

  17. Origin of subdiffusion of water molecules on cell membrane surfaces

    CERN Document Server

    Yamamoto, Eiji; Yasui, Masato; Yasuoka, Kenji

    2014-01-01

    Water molecules play an important role in providing unique environments for biological reactions on cell membranes. It is widely believed that water molecules form bridges that connect lipid molecules and stabilize cell membranes. Using all-atom molecular dynamics simulations, we show that translational and rotational diffusion of water molecules on lipid membrane surfaces exhibit subdiffusion. Moreover, we provide evidence that both divergent mean trapping time (continuous-time random walk) and long-correlated noise (fractional Brownian motion) contribute to this subdiffusion. These results suggest that subdiffusion on cell membranes causes the water retardation, an enhancement of cell membrane stability, and a higher reaction efficiency.

  18. Bistable cell fate specification as a result of stochastic fluctuations and collective spatial cell behaviour.

    Directory of Open Access Journals (Sweden)

    Daniel Stockholm

    Full Text Available BACKGROUND: In culture, isogenic mammalian cells typically display enduring phenotypic heterogeneity that arises from fluctuations of gene expression and other intracellular processes. This diversity is not just simple noise but has biological relevance by generating plasticity. Noise driven plasticity was suggested to be a stem cell-specific feature. RESULTS: Here we show that the phenotypes of proliferating tissue progenitor cells such as primary mononuclear muscle cells can also spontaneously fluctuate between different states characterized by the either high or low expression of the muscle-specific cell surface molecule CD56 and by the corresponding high or low capacity to form myotubes. Although this capacity is a cell-intrinsic property, the cells switch their phenotype under the constraints imposed by the highly heterogeneous microenvironment created by their own collective movement. The resulting heterogeneous cell population is characterized by a dynamic equilibrium between "high CD56" and "low CD56" phenotype cells with distinct spatial distribution. Computer simulations reveal that this complex dynamic is consistent with a context-dependent noise driven bistable model where local microenvironment acts on the cellular state by encouraging the cell to fluctuate between the phenotypes until the low noise state is found. CONCLUSIONS: These observations suggest that phenotypic fluctuations may be a general feature of any non-terminally differentiated cell. The cellular microenvironment created by the cells themselves contributes actively and continuously to the generation of fluctuations depending on their phenotype. As a result, the cell phenotype is determined by the joint action of the cell-intrinsic fluctuations and by collective cell-to-cell interactions.

  19. Hepatic Bel-7402 Cell Proliferation on Different Phospholipid Surfaces

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Phospholipids are believed to be important biomaterials.However, limited information is available on their cytocompatibilities.The objective of this study is to evaluate the effects of different phospholipids on the proliferation of hepatic Bel-7402 cells by comparing the adhesion, viability and proliferation of Bel-7402 cells cultured on different phospholipid surfaces.The cell adhesion, determined by counting the number of adhered cells to the surface, indicated that the cell adhesion was enhanced on charged phospolipid membranes.The cell viability evaluated by MTT[3 (4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium-bromide] showed that cells cultured on charged phospholipids have greater viability than those cultured on the control, while cells cultured on neutral phospholipids showed lower viability.The cell cycle analysis using flow cytometry demonstrated that S phase entry increased on charged phospholipids, while S phase entry decreased on neutral phospholipids.The results suggested that charged phospholipids, especially positively charged phospholipids, show better cytocompatibilities than neutral phospholipids to hepatic Bel-7402 cell.

  20. Understanding the Results of Electrostatics Calculations: Visualizing Molecular 'Isopotential' Surfaces

    OpenAIRE

    Mura, Cameron

    2016-01-01

    This document attempts to clarify potential confusion regarding electrostatics calculations, specifically in the context of biomolecular structure and specifically as regards the units typically used to contour/visualize isopotential surfaces, potentials mapped onto molecular solvent-accessible surfaces, etc.

  1. Reducing the In2O3(111) Surface Results in Ordered Indium Adatoms

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Margareta [Vienna University of Technology, Institute of Applied Physics, Austria; Seiler, Steffen [Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, Germany; Meyer, Bernd [Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, Germany; Boatner, Lynn A [ORNL; Schmid, M. [Technische Universitat Wien, Wiedner Hauptstrasse; Diebold, U. [Technische Universitat Wien, Wiedner Hauptstrasse

    2014-01-01

    The In2O3(111) surface can be transformed from an oxidized bulk termination to one that is covered by single In adatoms. As each adatom sits at one specific site within the surface unit cell they form a well-ordered (1 1) superstructure. Annealing at 500 C in O2 or in ultrahigh vacuum results in a fully reversible conversion between these two surface terminations; this transformation and intermediate stages were followed with Scanning Tunneling Microscopy (STM). Formation of this novel surface structure under reducing conditions is corroborated by Density Functional Theory (DFT). The reduced adatom-covered and the oxidized In2O3(111) surfaces are expected to exhibit different chemical and electronic properties, which can easily be exploited by the facile and reversible switching between the two terminations.

  2. The Role of Surface Receptor Density in Surface-Initiated Polymerizations for Cancer Cell Isolation.

    Science.gov (United States)

    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

  3. CZTSSe thin film solar cells: Surface treatments

    Science.gov (United States)

    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.

  4. Multijunction Solar Cells Optimized for the Mars Surface Solar Spectrum

    Science.gov (United States)

    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.

  5. Studies on cell adhesion and recognition. II. The kinetics of cell adhesion and cell spreading on surfaces coated with carbohydrate- reactive proteins (glycosidases and lectins) and fibronectin

    OpenAIRE

    1981-01-01

    The kinetics of cell attachment and cell spreading on the coated surfaces of two classes of carbohydrate-reactive proteins, enzymes and lectins, have been compared with those on fibronectin-coated surfaces with the following results: (a) A remarkable similarity between the kinetics of cell attachment to fibronectin-coated and glycosidase- coated surfaces was found. In contrast, cell attachment kinetics induced by lectin- and galactose oxidase-coated surfaces, in general, were strikingly diffe...

  6. Frequency Selective Surfaces with Nanoparticles Unit Cell

    Directory of Open Access Journals (Sweden)

    Nga Hung Poon

    2015-09-01

    Full Text Available The frequency selective surface (FSS is a periodic structure with filtering performance for optical and microwave signals. The general periodic arrays made with patterned metallic elements can act as an aperture or patch on a substrate. In this work, two kinds of materials were used to produce unit cells with various patterns. Gold nanoparticles of 25 nm diameter were used to form periodic monolayer arrays by a confined photocatalytic oxidation-based surface modification method. As the other material, silver gel was used to create multiple layers of silver. Due to the ultra-thin nature of the self-assembled gold nanoparticle monolayer, it is very easy to penetrate the FSS with terahertz radiation. However, the isolated silver islands made from silver gel form thicker multiple layers and contribute to much higher reflectance. This work demonstrated that multiple silver layers are more suitable than gold nanoparticles for use in the fabrication of FSS structures.

  7. Subwavelength topological structures resulting from surface two-plasmon resonance by femtosecond laser exposure solid surface.

    Science.gov (United States)

    Song, Hai-Ying; Liu, Shi-Bing; Liu, H Y; Wang, Yang; Chen, Tao; Dong, Xiang-Ming

    2016-05-30

    We present that surface two-plasmon resonance (STPR) in electron plasma sheet produced by a femtosecond laser irradiating a solid surface is the self-formation mechanism of periodic subwavelength ripple structures. Peaks of overdense electrons, formed by resonant two-plasmon wave mode, pull bound ions out of the metal surface. Thus, the wave pattern of STPR is "carved" on the surface by Coulomb ablation (removal) due to periodic distributed strong electrostatic field produced by charge separation. To confirm the STPR model, we have performed analogical carving experiments by two femtosecond laser beams with perpendicular polarizations and time delay. The results explicitly show that two wave patterns of STPR generated by each beam are independently created in the pulse exposure area of a target surface, which is like the traditional "layer-carving" technique by comparison with the structured topological features. The time-scale of ablation dynamics and the electron temperature in ultrafast interaction are also verified by a time-resolved spectroscopy experiment and numerical simulation, respectively. The present model can self-consistently explain the formation of subwavelength ripple structures even with spatial periods shorter than half of the laser wavelength, shedding light on the understanding of ultrafast laser-solid interaction. PMID:27410135

  8. Recent results on aqueous electrolyte cells

    KAUST Repository

    Wessells, Colin

    2011-03-01

    The improved safety of aqueous electrolytes makes aqueous lithium-ion batteries an attractive alternative to commercial cells utilizing flammable and expensive organic electrolytes. Two important issues relating to their use have been addressed in this work. One is the extension of the usable voltage range by the incorporation of lithium salts, and the other is the investigation of a useful negative electrode reactant, LiTi 2(PO 4) 3. The electrochemical stability of aqueous lithium salt solutions containing two lithium salts, LiNO 3 and Li 2SO 4, has been characterized using a constant current technique. In both cases, concentrated solutions had effective electrolyte stability windows substantially greater than that of pure water under standard conditions. At an electrolyte leakage current of 10 μA cm -2 between two platinum electrodes in 5 M LiNO 3 the cell voltage can reach 2.0 V, whereas with a leakage current of 50 μA cm -2 it can reach 2.3 V. LiTi 2(PO 4) 3 was synthesized using a Pechini method and cycled in pH-neutral Li 2SO 4. At a reaction potential near the lower limit of electrolyte stability, an initial discharge capacity of 118 mAh g -1 was measured at a C/5 rate, while about 90% of this discharge capacity was retained after 100 cycles. This work demonstrates that it is possible to have useful aqueous electrolyte lithium-ion batteries using the LiTi 2(PO 4) 3 anode with cell voltages of 2 V and above. © 2010 Elsevier B.V. All rights reserved.

  9. Wettability influences cell behavior on superhydrophobic surfaces with different topographies

    NARCIS (Netherlands)

    Lourenco, B.N.; Marchioli, G.; Song, W; Reis, R.L.; Blitterswijk, van C.A.; Karperien, H.B.J.; Apeldoorn, van A.A.; Mano, J.F.

    2012-01-01

    Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavi

  10. 3D surface topology guides stem cell adhesion and differentiation.

    Science.gov (United States)

    Viswanathan, Priyalakshmi; Ondeck, Matthew G; Chirasatitsin, Somyot; Ngamkham, Kamolchanok; Reilly, Gwendolen C; Engler, Adam J; Battaglia, Giuseppe

    2015-06-01

    Polymerized high internal phase emulsion (polyHIPE) foams are extremely versatile materials for investigating cell-substrate interactions in vitro. Foam morphologies can be controlled by polymerization conditions to result in either open or closed pore structures with different levels of connectivity, consequently enabling the comparison between 2D and 3D matrices using the same substrate with identical surface chemistry conditions. Additionally, here we achieve the control of pore surface topology (i.e. how different ligands are clustered together) using amphiphilic block copolymers as emulsion stabilizers. We demonstrate that adhesion of human mesenchymal progenitor (hES-MP) cells cultured on polyHIPE foams is dependent on foam surface topology and chemistry but is independent of porosity and interconnectivity. We also demonstrate that the interconnectivity, architecture and surface topology of the foams has an effect on the osteogenic differentiation potential of hES-MP cells. Together these data demonstrate that the adhesive heterogeneity of a 3D scaffold could regulate not only mesenchymal stem cell attachment but also cell behavior in the absence of soluble growth factors.

  11. Surface deformation resulting from subduction and slab detachment

    NARCIS (Netherlands)

    Buiter, S.J.H.

    2000-01-01

    Convergence of lithospheric plates is accommodated at active margins by one plate moving beneath the other into the Earth's mantle. Changes in this subduction process may cause variations in the topography of the Earth's surface near a convergent plate margin. The focus of this thesis lies on surfac

  12. Surface-enhanced Raman spectroscopy of the endothelial cell membrane.

    Directory of Open Access Journals (Sweden)

    Simon W Fogarty

    Full Text Available We applied surface-enhanced Raman spectroscopy (SERS to cationic gold-labeled endothelial cells to derive SERS-enhanced spectra of the bimolecular makeup of the plasma membrane. A two-step protocol with cationic charged gold nanoparticles followed by silver-intensification to generate silver nanoparticles on the cell surface was employed. This protocol of post-labelling silver-intensification facilitates the collection of SERS-enhanced spectra from the cell membrane without contribution from conjugated antibodies or other molecules. This approach generated a 100-fold SERS-enhancement of the spectral signal. The SERS spectra exhibited many vibrational peaks that can be assigned to components of the cell membrane. We were able to carry out spectral mapping using some of the enhanced wavenumbers. Significantly, the spectral maps suggest the distribution of some membrane components are was not evenly distributed over the cells plasma membrane. These results provide some possible evidence for the existence of lipid rafts in the plasma membrane and show that SERS has great potential for the study and characterization of cell surfaces.

  13. Surface plasmon resonance imaging of cells and surface-associated fibronectin

    Directory of Open Access Journals (Sweden)

    Bhadriraju Kiran

    2009-02-01

    Full Text Available Abstract Background A critical challenge in cell biology is quantifying the interactions of cells with their extracellular matrix (ECM environment and the active remodeling by cells of their ECM. Fluorescence microscopy is a commonly employed technique for examining cell-matrix interactions. A label-free imaging method would provide an alternative that would eliminate the requirement of transfected cells and modified biological molecules, and if collected nondestructively, would allow long term observation and analysis of live cells. Results Using surface plasmon resonance imaging (SPRI, the deposition of protein by vascular smooth muscle cells (vSMC cultured on fibronectin was quantified as a function of cell density and distance from the cell periphery. We observed that as much as 120 ng/cm2 of protein was deposited by cells in 24 h. Conclusion SPRI is a real-time, low-light-level, label-free imaging technique that allows the simultaneous observation and quantification of protein layers and cellular features. This technique is compatible with live cells such that it is possible to monitor cellular modifications to the extracellular matrix in real-time.

  14. Chemistry and material science at the cell surface

    Directory of Open Access Journals (Sweden)

    Weian Zhao

    2010-04-01

    Full Text Available Cell surfaces are fertile ground for chemists and material scientists to manipulate or augment cell functions and phenotypes. This not only helps to answer basic biology questions but also has diagnostic and therapeutic applications. In this review, we summarize the most recent advances in the engineering of the cell surface. In particular, we focus on the potential applications of surface engineered cells for 1 targeting cells to desirable sites in cell therapy, 2 programming assembly of cells for tissue engineering, 3 bioimaging and sensing, and ultimately 4 manipulating cell biology.

  15. Brown spider venom toxins interact with cell surface and are endocytosed by rabbit endothelial cells.

    Science.gov (United States)

    Nowatzki, Jenifer; de Sene, Reginaldo Vieira; Paludo, Katia Sabrina; Veiga, Silvio Sanches; Oliver, Constance; Jamur, Maria Célia; Nader, Helena Bonciani; Trindade, Edvaldo S; Franco, Célia Regina C

    2010-09-15

    Bites from the Loxosceles genus (brown spiders) cause severe clinical symptoms, including dermonecrotic injury, hemorrhage, hemolysis, platelet aggregation and renal failure. Histological findings of dermonecrotic lesions in animals exposed to Loxosceles intermedia venom show numerous vascular alterations. Study of the hemorrhagic consequences of the venom in endothelial cells has demonstrated that the degeneration of blood vessels results not only from degradation of the extracellular matrix molecule or massive leukocyte infiltration, but also from a direct and primary activity of the venom on endothelial cells. Exposure of an endothelial cell line in vitro to L. intermedia venom induce morphological alterations, such as cell retraction and disadhesion to the extracellular matrix. The aim of the present study was to investigate the interaction between the venom toxins and the endothelial cell surface and their possible internalization, in order to illuminate the information about the deleterious effect triggered by venom. After treating endothelial cells with venom toxins, we observed that the venom interacts with cell surface. Venom treatment also can cause a reduction of cell surface glycoconjugates. When cells were permeabilized, it was possible to verify that some venom toxins were internalized by the endothelial cells. The venom internalization involves endocytic vesicles and the venom was detected in the lysosomes. However, no damage to lysosomal integrity was observed, suggesting that the cytotoxic effect evoked by L. intermedia venom on endothelial cells is not mediated by venom internalization.

  16. Interaction of KSHV with Host Cell Surface Receptors and Cell Entry

    Directory of Open Access Journals (Sweden)

    Mohanan Valiya Veettil

    2014-10-01

    Full Text Available Virus entry is a complex process characterized by a sequence of events. Since the discovery of KSHV in 1994, tremendous progress has been made in our understanding of KSHV entry into its in vitro target cells. KSHV entry is a complex multistep process involving viral envelope glycoproteins and several cell surface molecules that is utilized by KSHV for its attachment and entry. KSHV has a broad cell tropism and the attachment and receptor engagement on target cells have an important role in determining the cell type-specific mode of entry. KSHV utilizes heparan sulfate, integrins and EphrinA2 molecules as receptors which results in the activation of host cell pre-existing signal pathways that facilitate the subsequent cascade of events resulting in the rapid entry of virus particles, trafficking towards the nucleus followed by viral and host gene expression. KSHV enters human fibroblast cells by dynamin dependant clathrin mediated endocytosis and by dynamin independent macropinocytosis in dermal endothelial cells. Once internalized into endosomes, fusion of the viral envelope with the endosomal membranes in an acidification dependent manner results in the release of capsids which subsequently reaches the nuclear pore vicinity leading to the delivery of viral DNA into the nucleus. In this review, we discuss the principal mechanisms that enable KSHV to interact with the host cell surface receptors as well as the mechanisms that are required to modulate cell signaling machinery for a successful entry.

  17. Interaction of progenitor bone cells with different surface modifications of titanium implant

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Chen, Ya-Shun [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Ko, Chia-Ling [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Dental Medical Devices and Materials Research Center, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Lin, Yi; Kuo, Tzu-Huang; Kuo, Hsien-Nan [Medical Device Development Division, Metal Industries Research and Development Centre, Kaohsiung 82151, Taiwan (China)

    2014-04-01

    Changes in the physical and chemical properties of Ti surfaces can be attributed to cell performance, which improves surface biocompatibility. The cell proliferation, mineralization ability, and gene expression of progenitor bone cells (D1 cell) were compared on five different Ti surfaces, namely, mechanical grinding (M), electrochemical modification through potentiostatic anodization (ECH), sandblasting and acid etching (SLA), sandblasting, hydrogen peroxide treatment, and heating (SAOH), and sandblasting, alkali heating, and etching (SMART). SAOH treatment produced the most hydrophilic surface, whereas SLA produced the most hydrophobic surface. Cell activity indicated that SLA and SMART produced significantly rougher surfaces and promoted D1 cell attachment within 1 day of culturing, whereas SAOH treatment produced moderate roughness (Ra = 1.26 μm) and accelerated the D1 cell proliferation up to 7 days after culturing. The ECH surface significantly promoted alkaline phosphatase (ALP) expression and osteocalcin (OCN) secretion in the D1 cells compared with the other surface groups. The ECH and SMART-treated Ti surfaces resulted in maximum ALP and OCN expressions during the D1 cell culture. SLA, SAOH, and SMART substrate surfaces were rougher and exhibited better cell metabolic responses during the early stage of cell attachment, proliferation, and morphologic expressions within 1 day of D1 cell culture. The D1 cells cultured on the ECH and SMART substrates exhibited higher differentiation, and higher ALP and OCN expressions after 10 days of culture. Thus, the ECH and SMART treatments promote better ability of cell mineralization in vitro, which demonstrate their great potential for clinical use. - Highlights: • Progenitor bone cells onto Ti with different modifications are characterized. • Surface roughness and hydrophilicity encourage early stage cell attachment. • Composition and surface treatments are more vital in bone cell mineralization.

  18. Interaction of progenitor bone cells with different surface modifications of titanium implant

    International Nuclear Information System (INIS)

    Changes in the physical and chemical properties of Ti surfaces can be attributed to cell performance, which improves surface biocompatibility. The cell proliferation, mineralization ability, and gene expression of progenitor bone cells (D1 cell) were compared on five different Ti surfaces, namely, mechanical grinding (M), electrochemical modification through potentiostatic anodization (ECH), sandblasting and acid etching (SLA), sandblasting, hydrogen peroxide treatment, and heating (SAOH), and sandblasting, alkali heating, and etching (SMART). SAOH treatment produced the most hydrophilic surface, whereas SLA produced the most hydrophobic surface. Cell activity indicated that SLA and SMART produced significantly rougher surfaces and promoted D1 cell attachment within 1 day of culturing, whereas SAOH treatment produced moderate roughness (Ra = 1.26 μm) and accelerated the D1 cell proliferation up to 7 days after culturing. The ECH surface significantly promoted alkaline phosphatase (ALP) expression and osteocalcin (OCN) secretion in the D1 cells compared with the other surface groups. The ECH and SMART-treated Ti surfaces resulted in maximum ALP and OCN expressions during the D1 cell culture. SLA, SAOH, and SMART substrate surfaces were rougher and exhibited better cell metabolic responses during the early stage of cell attachment, proliferation, and morphologic expressions within 1 day of D1 cell culture. The D1 cells cultured on the ECH and SMART substrates exhibited higher differentiation, and higher ALP and OCN expressions after 10 days of culture. Thus, the ECH and SMART treatments promote better ability of cell mineralization in vitro, which demonstrate their great potential for clinical use. - Highlights: • Progenitor bone cells onto Ti with different modifications are characterized. • Surface roughness and hydrophilicity encourage early stage cell attachment. • Composition and surface treatments are more vital in bone cell mineralization.

  19. Proteomics and glycoproteomics of pluripotent stem-cell surface proteins.

    Science.gov (United States)

    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

  20. Proteomics and glycoproteomics of pluripotent stem-cell surface proteins.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  2. Nanofabrication of Nonfouling Surfaces for Micropatterning of Cell and Microtissue

    Directory of Open Access Journals (Sweden)

    Hidenori Otsuka

    2010-08-01

    Full Text Available Surface engineering techniques for cellular micropatterning are emerging as important tools to clarify the effects of the microenvironment on cellular behavior, as cells usually integrate and respond the microscale environment, such as chemical and mechanical properties of the surrounding fluid and extracellular matrix, soluble protein factors, small signal molecules, and contacts with neighboring cells. Furthermore, recent progress in cellular micropatterning has contributed to the development of cell-based biosensors for the functional characterization and detection of drugs, pathogens, toxicants, and odorants. In this regards, the ability to control shape and spreading of attached cells and cell-cell contacts through the form and dimension of the cell-adhesive patches with high precision is important. Commitment of stem cells to different specific lineages depends strongly on cell shape, implying that controlled microenvironments through engineered surfaces may not only be a valuable approach towards fundamental cell-biological studies, but also of great importance for the design of cell culture substrates for tissue engineering. To develop this kind of cellular microarray composed of a cell-resistant surface and cell attachment region, micropatterning a protein-repellent surface is important because cellular adhesion and proliferation are regulated by protein adsorption. The focus of this review is on the surface engineering aspects of biologically motivated micropatterning of two-dimensional surfaces with the aim to provide an introductory overview described in the literature. In particular, the importance of non-fouling surface chemistries is discussed.

  3. Tooth-surface-specific Effects of Xylitol: Randomized Trial Results

    OpenAIRE

    Ritter, A.V.; Bader, J.D.; Leo, M. C.; Preisser, J.S.; Shugars, D.A.; Vollmer, W.M.; Amaechi, B.T.; Holland, J.C.

    2013-01-01

    The Xylitol for Adult Caries Trial was a three-year, double-blind, multi-center, randomized clinical trial that evaluated the effectiveness of xylitol vs. placebo lozenges in the prevention of dental caries in caries-active adults. The purpose of this secondary analysis was to investigate whether xylitol lozenges had a differential effect on cumulative caries increments on different tooth surfaces. Participants (ages 21-80 yrs) with at least one follow-up visit (n = 620) were examined at base...

  4. Osteoblast cell response to surface-modified carbon nanotubes

    International Nuclear Information System (INIS)

    In order to investigate the interaction of cells with modified multi-walled carbon nanotubes (MWCNTs) for their potential biomedical applications, the MWCNTs were chemically modified with carboxylic acid groups (–COOH), polyvinyl alcohol (PVA) polymer and biomimetic apatite on their surfaces. Additionally, human osteoblast MG-63 cells were cultured in the presence of the surface-modified MWCNTs. The metabolic activities of osteoblastic cells, cell proliferation properties, as well as cell morphology were studied. The surface modification of MWCNTs with biomimetic apatite exhibited a significant increase in the cell viability of osteoblasts, up to 67.23%. In the proliferation phases, there were many more cells in the biomimetic apatite-modified MWCNT samples than in the MWCNTs–COOH. There were no obvious changes in cell morphology in osteoblastic MG-63 cells cultured in the presence of these chemically-modified MWCNTs. The surface modification of MWCNTs with apatite achieves an effective enhancement of their biocompatibility.

  5. The effect of cerium valence states at cerium oxide nanoparticle surfaces on cell proliferation

    KAUST Repository

    Naganuma, Tamaki

    2014-05-01

    Understanding and controlling cell proliferation on biomaterial surfaces is critical for scaffold/artificial-niche design in tissue engineering. The mechanism by which underlying integrin ligates with functionalized biomaterials to induce cell proliferation is still not completely understood. In this study, poly-l-lactide (PL) scaffold surfaces were functionalized using layers of cerium oxide nanoparticles (CNPs), which have recently attracted attention for use in therapeutic application due to their catalytic ability of Ce4+ and Ce3+ sites. To isolate the influence of Ce valance states of CNPs on cell proliferation, human mesenchymal stem cells (hMSCs) and osteoblast-like cells (MG63) were cultured on the PL/CNP surfaces with dominant Ce4+ and Ce3+ regions. Despite cell type (hMSCs and MG63 cells), different surface features of Ce4+ and Ce3+ regions clearly promoted and inhibited cell spreading, migration and adhesion behavior, resulting in rapid and slow cell proliferation, respectively. Cell proliferation results of various modified CNPs with different surface charge and hydrophobicity/hydrophilicity, indicate that Ce valence states closely correlated with the specific cell morphologies and cell-material interactions that trigger cell proliferation. This finding suggests that the cell-material interactions, which influence cell proliferation, may be controlled by introduction of metal elements with different valence states onto the biomaterial surface. © 2014 Elsevier Ltd.

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

    OpenAIRE

    Kou, Peng Meng; Schwartz, Zvi; Boyan, Barbara D; Babensee, Julia E.

    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. Clinic...

  7. Melittin interaction with sulfated cell surface sugars.

    Science.gov (United States)

    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

  8. Inelastic electron holography: First results with surface plasmons

    Energy Technology Data Exchange (ETDEWEB)

    Falk, Roeder; Hannes, Lichte [Triebenberg Labor, Institute for Structure Physics, TU Dresden, 01062 Dresden (Germany)

    2011-07-01

    Inelastic interaction and wave optics seem to be incompatible in that inelastic processes destroy coherence, which is the fundamental requirement for holography. In special experiments it is shown that energy transfer larger than some undoubtedly destroys coherence of the inelastic electron with the elastic remainder. Consequently, the usual inelastic processes, such as phonon-, plasmon- or inner shell-excitations with energy transfer of several out to several, certainly produce incoherence with the elastic ones. However, it turned out that within the inelastic wave, *newborn* by the inelastic process, there is a sufficiently wide area of coherence for generating *inelastic holograms*. This is exploited to create holograms with electrons scattered at surface-plasmons, which opens up quantum mechanical investigation of these inelastic processes.

  9. Phospholipid polymer-based antibody immobilization for cell rolling surfaces in stem cell purification system.

    Science.gov (United States)

    Mahara, Atsushi; Chen, Hao; Ishihara, Kazuhiko; Yamaoka, Tetsuji

    2014-01-01

    We previously developed an antibody-conjugated cell rolling column that successfully separates stem cell subpopulations depending on the cell surface marker density, but a large amount of the injected cells were retained in the column because of non-specific interactions. In this study, an amphiphilic copolymer, poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate (nBMA)-co-N-vinyl formamide (NVf)], with phospholipid polar side groups was designed as a novel antibody-immobilizing modifier. The formamide groups in NVf units were converted to active maleimide groups. A plastic flow microfluidic chamber was coated with the copolymers, and a reduced anti-CD90 antibody was immobilized. The adipose tissue-derived stem cells isolated from the rat were injected into the flow chamber, and their rolling behavior was observed under a microscope with a high-speed camera. Non-specific cell adhesion was reduced strongly by means of this immobilization method because of the MPC unit, resulting in a high percentage of rolling cells. These results demonstrate that a surface coated with phospholipid polar groups can be used in an effective stem cell separation system based on the cell rolling process.

  10. Surface recombination analysis in silicon-heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Barrio, R.; Gandia, J.J.; Carabe, J.; Gonzalez, N.; Torres, I. [CIEMAT, Madrid (Spain); Munoz, D.; Voz, C. [Universitat Politecnica de Catalunya, Barcelona (Spain)

    2010-02-15

    The origin of this work is the understanding of the correlation observed between efficiency and emitter-deposition temperature in single silicon-heterojunction solar cells prepared by depositing an n-doped hydrogenated-amorphous-silicon thin film onto a p-type crystalline-silicon wafer. In order to interpret these results, surface-recombination velocities have been determined by two methods, i.e. by fitting the current-voltage characteristics to a theoretical model and by means of the Quasi-Steady-State Photoconductance Technique (QSSPC). In addition, effective diffusion lengths have been estimated from internal quantum efficiencies. The analysis of these data has led to conclude that the performance of the cells studied is limited by back-surface recombination rather than by front-heterojunction quality. A 12%-efficient cell has been prepared by combining optimum emitter-deposition conditions with back-surface-field (BSF) formation by vacuum annealing of the back aluminium contact. This result has been achieved without using any transparent conductive oxide. (author)

  11. Calreticulin: Roles in Cell-Surface Protein Expression

    Directory of Open Access Journals (Sweden)

    Yue Jiang

    2014-09-01

    Full Text Available 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.

  12. Fibronectin on the Surface of Myeloma Cell-derived Exosomes Mediates Exosome-Cell Interactions.

    Science.gov (United States)

    Purushothaman, Anurag; Bandari, Shyam Kumar; Liu, Jian; Mobley, James A; Brown, Elizabeth E; Sanderson, Ralph D

    2016-01-22

    Exosomes regulate cell behavior by binding to and delivering their cargo to target cells; however, the mechanisms mediating exosome-cell interactions are poorly understood. Heparan sulfates on target cell surfaces can act as receptors for exosome uptake, but the ligand for heparan sulfate on exosomes has not been identified. Using exosomes isolated from myeloma cell lines and from myeloma patients, we identify exosomal fibronectin as a key heparan sulfate-binding ligand and mediator of exosome-cell interactions. We discovered that heparan sulfate plays a dual role in exosome-cell interaction; heparan sulfate on exosomes captures fibronectin, and on target cells it acts as a receptor for fibronectin. Removal of heparan sulfate from the exosome surface releases fibronectin and dramatically inhibits exosome-target cell interaction. Antibody specific for the Hep-II heparin-binding domain of fibronectin blocks exosome interaction with tumor cells or with marrow stromal cells. Regarding exosome function, fibronectin-mediated binding of exosomes to myeloma cells activated p38 and pERK signaling and expression of downstream target genes DKK1 and MMP-9, two molecules that promote myeloma progression. Antibody against fibronectin inhibited the ability of myeloma-derived exosomes to stimulate endothelial cell invasion. Heparin or heparin mimetics including Roneparstat, a modified heparin in phase I trials in myeloma patients, significantly inhibited exosome-cell interactions. These studies provide the first evidence that fibronectin binding to heparan sulfate mediates exosome-cell interactions, revealing a fundamental mechanism important for exosome-mediated cross-talk within tumor microenvironments. Moreover, these results imply that therapeutic disruption of fibronectin-heparan sulfate interactions will negatively impact myeloma tumor growth and progression.

  13. Distribution, Arrangement and Interconnectedness of Cell Surface Receptor sites in the body of an Organism

    Directory of Open Access Journals (Sweden)

    Utoh-Nedosa

    2011-01-01

    Full Text Available Cell surface receptors have been identified as the sites of disease infectivity in living organisms in a previous study. Drugs used for the treatment or cure of infections have to eliminate infections through attacking infective organisms at the cell surface receptors to which the infective organisms are attached. Problem statement: The present study examines a wide sample of living things to get more information on the relationship of one cell surface receptor to other cell surface receptors in the body of an organism. Approach: The arrangement of cell surface receptors on the external covering of a few samples of fruits, leaves, stems, dry wood of a plant; wall gecko and some parts of the human body, were examined and photographed. Transverse and/or Longitudinal sections of soursop fruit and sycamore fruit were also examined and photographed. The five different coverings of the fleshy part of a coconut were also photographed. The photographs were studied to note the relationship of disease infection attached to cell surface receptors on the external surface of an organ to disease infection on the innermost covering of the same organ. Results: The results of the study showed that all living things had ubiquitous distribution of cell surface receptors which are usually observable with the unaided eye as dots or spots on the external covering of an organ, tissue or cell. The dots or receptor sites of cell surface receptors in the study are arranged in lines which were perpendicular, oblique, transverse or arranged in any other lineal geometrical form. The lineally arranged cell surface receptors were noted to be connected by grooves, channels or pipes which joined other receptor channels or intersected with them. Smaller cell surface receptor channels emptied into bigger channels or continued as small sized channels that ran side by side in a connective tissue bundle. These connective tissue bundles that carried many independent small-sized cell

  14. Preliminary results report: Conasauga near-surface heater experiment

    Energy Technology Data Exchange (ETDEWEB)

    Krumhansl, J.L.

    1979-06-01

    From November 1977 to August 1978, two near-surface heater experiments were operated in two somewhat different stratigraphic sequences within the Conasauga formation which consist predominantly of shale. Specific phenomena investigated were the thermal and mechanical responses of the formation to an applied heat load, as well as the mineralogical changes induced by heating. Objective was to provide a minimal integrated field and laboratory study that would supply a data base which could be used in planning more expensive and complex vault-type experiments in other localities. The experiments were operated with heater power levels of between 6 and 8 kW for heater mid-plane temperatures of 385/sup 0/C. The temperature fields within the shale were measured and analysis is in progress. Steady state conditions were achieved within 90 days. Conduction appears to be the principal mechanism of heat transport through the formation. Limited mechanical response measurements consisting of vertical displacement and stress data indicate general agreement with predictions. Posttest data, collection of which await experiment shutdown and cooling of the formation, include the mineralogy of posttest cores, posttest transmissivity measurements and corrosion data on metallurgical samples.

  15. Preliminary results report: Conasauga near-surface heater experiment

    International Nuclear Information System (INIS)

    From November 1977 to August 1978, two near-surface heater experiments were operated in two somewhat different stratigraphic sequences within the Conasauga formation which consist predominantly of shale. Specific phenomena investigated were the thermal and mechanical responses of the formation to an applied heat load, as well as the mineralogical changes induced by heating. Objective was to provide a minimal integrated field and laboratory study that would supply a data base which could be used in planning more expensive and complex vault-type experiments in other localities. The experiments were operated with heater power levels of between 6 and 8 kW for heater mid-plane temperatures of 3850C. The temperature fields within the shale were measured and analysis is in progress. Steady state conditions were achieved within 90 days. Conduction appears to be the principal mechanism of heat transport through the formation. Limited mechanical response measurements consisting of vertical displacement and stress data indicate general agreement with predictions. Posttest data, collection of which await experiment shutdown and cooling of the formation, include the mineralogy of posttest cores, posttest transmissivity measurements and corrosion data on metallurgical samples

  16. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kaklamani, Georgia, E-mail: g.kaklamani@bham.ac.uk [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom); Bowen, James; Mehrban, Nazia [University of Birmingham, College of Engineering and Physical Sciences, School of Chemical Engineering, Edgbaston, Birmingham B15 2TT (United Kingdom); Dong, Hanshan [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom); Grover, Liam M. [University of Birmingham, College of Engineering and Physical Sciences, School of Chemical Engineering, Edgbaston, Birmingham B15 2TT (United Kingdom); Stamboulis, Artemis [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2013-05-15

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N{sub 2}/H{sub 2} ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of C-N, C=N, and C≡N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  17. Glioma Cell Proliferation Controlled by ERK Activity-Dependent Surface Expression of PDGFRA

    OpenAIRE

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

    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. G...

  18. Association of cell surface heparan sulfate proteoglycans of Schwann cells with extracellular matrix proteins.

    Science.gov (United States)

    Carey, D J; Crumbling, D M; Stahl, R C; Evans, D M

    1990-11-25

    The terminal differentiation of Schwann cells is dependent on contact with basement membrane. The present study was undertaken to investigate the role of cell surface heparan sulfate proteoglycans (HSPGs) in mediating Schwann cell responses to extracellular matrix contact. Phosphatidylinositol-specific phospholipase C-releasable cell surface HSPGs purified from cultures of neonatal rat Schwann cells were subjected to affinity chromatography on immobilized laminin and fibronectin. Binding of the HSPG to both affinity matrices was observed. The strength of the association, however, was sensitive to the ionic strength of the buffer. In 0.1 M Tris-HCl, HSPG binding was essentially irreversible whereas in physiological ionic strength buffer (e.g. 0.142 M NaCl, 10 mM Tris), weaker binding was detected as a delay in elution of the HSPG from the affinity columns. Further studies of HSPG-laminin binding suggested that the binding was mediated by the glycosaminoglycan chains of the proteoglycans. Results of equilibrium gel filtration chromatography provided additional evidence for a reversible association of the HSPG and laminin with a Kd of approximately 1 x 10(-6) M. When Schwann cells were plated on plastic dishes coated with laminin, the cells attached and extended long slender processes. Inclusion of heparin, but not chondroitin sulfate, in the assay medium resulted in partial inhibition of process extension, but at concentrations of heparin which were higher than that needed to disrupt laminin-HSPG association in vitro. Addition of anti-integrin receptor antibodies resulted in more extensive inhibition of laminin-dependent process extension. Anti-integrin antibodies plus heparin essentially totally inhibited laminin-dependent process extension. These results demonstrate that cell surface HSPGs are capable of reversible association with extracellular matrix molecules and suggest that HSPG-laminin interactions play a role in laminin-dependent Schwann cell spreading. PMID

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

    Science.gov (United States)

    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.

    Science.gov (United States)

    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. Morphological investigations of cells that adhered to the irregular patterned polydimethylsiloxane (PDMS) surface without reagents.

    Science.gov (United States)

    Chung, Sung Hee; Min, Junhong

    2009-07-01

    Polydimethylsiloxane (PDMS) surface consisting irregular pattern was investigated to develop cell-based biochip using PDMS. PDMS surface was modified with nano- and micro-combined patterns using surface deformation technology. Hydrophobicity of nano-patterned PDMS surface was sustained. Nevertheless it has irregular patterns consisting of micro- and nano-patterns. According to atomic force microscopy (AFM), scanning electron microscopy (SEM) and confocal microscopy results by immunostaining method, human mammary epithelial cells (HMEC) adhered well on irregularly patterned surface without any reagents such as gelatin and collagen, compared to commercial culture dish. It implies PDMS material can be utilized as template for cell-based biochip without any reagents. PMID:19427124

  2. Distinct roles for dystroglycan, beta1 integrin and perlecan in cell surface laminin organization

    DEFF Research Database (Denmark)

    Henry, M D; Satz, J S; Brakebusch, C;

    2001-01-01

    integrin-deficient ES cells, laminin-1 binds to the cell surface, but fails to organize into more morphologically complex structures. This result indicates that beta1 integrin function is required after DG function in the cell surface-mediated laminin assembly process. In perlecan-deficient ES cells......, the formation of complex laminin-1 structures is defective, implicating perlecan in the laminin matrix assembly process. Moreover, laminin and perlecan reciprocally modulate the organization of the other on the cell surface. Taken together, the data support a model whereby DG serves as a receptor essential......Dystroglycan (DG) is a cell surface receptor for several extracellular matrix (ECM) molecules including laminins, agrin and perlecan. Recent data indicate that DG function is required for the formation of basement membranes in early development and the organization of laminin on the cell surface...

  3. Cell receptor and surface ligand density effects on dynamic states of adhering circulating tumor cells.

    Science.gov (United States)

    Zheng, Xiangjun; Cheung, Luthur Siu-Lun; Schroeder, Joyce A; Jiang, Linan; Zohar, Yitshak

    2011-10-21

    Dynamic states of cancer cells moving under shear flow in an antibody-functionalized microchannel are investigated experimentally and theoretically. The cell motion is analyzed with the aid of a simplified physical model featuring a receptor-coated rigid sphere moving above a solid surface with immobilized ligands. The motion of the sphere is described by the Langevin equation accounting for the hydrodynamic loadings, gravitational force, receptor-ligand bindings, and thermal fluctuations; the receptor-ligand bonds are modeled as linear springs. Depending on the applied shear flow rate, three dynamic states of cell motion have been identified: (i) free motion, (ii) rolling adhesion, and (iii) firm adhesion. Of particular interest is the fraction of captured circulating tumor cells, defined as the capture ratio, via specific receptor-ligand bonds. The cell capture ratio decreases with increasing shear flow rate with a characteristic rate. Based on both experimental and theoretical results, the characteristic flow rate increases monotonically with increasing either cell-receptor or surface-ligand density within certain ranges. Utilizing it as a scaling parameter, flow-rate dependent capture ratios for various cell-surface combinations collapse onto a single curve described by an exponential formula.

  4. Surface deformation and shear flow in ligand mediated cell adhesion

    Science.gov (United States)

    Sircar, Sarthok; Roberts, Anthony; Sarthok Sircar / Anthony Roberts Collaboration

    We present a unified, multiscale model to study the attachment/detachment dynamics of two deforming, near spherical cells, coated with binding ligands and subject to a slow, homogeneous shear flow in a viscous fluid medium. The binding ligands on the surface of the cells experience attractive and repulsive forces in an ionic medium and exhibit finite resistance to rotation via bond tilting. The microscale drag forces and couples describing the fluid flow inside the small separation gap between the cells, are calculated using a combination of methods in lubrication theory and previously published numerical results. For a select range of material and fluid parameters, a hysteretic transition of the sticking probability curves (i.e., the function g*) between the adhesion phase (when g*>0.5) and the fragmentation phase (when g*University startup funds and AR is supported by the Australian Research Council Discovery Grant DP150102385.

  5. Advances in targeting cell surface signalling molecules for immune modulation

    Science.gov (United States)

    Yao, Sheng; Zhu, Yuwen; Chen, Lieping

    2013-01-01

    The past decade has witnessed a surge in the development of immunomodulatory approaches to combat a broad range of human diseases, including cancer, viral infections, autoimmunity and inflammation as well as in the prevention of transplant rejection. Immunomodulatory approaches mostly involve the use of monoclonal antibodies or recombinant fusion proteins that target cell surface signalling molecules on immune cells to drive immune responses towards the desired direction. Advances in our understanding of the human immune system, along with valuable lessons learned from the first generation of therapeutic biologics, are aiding the design of the next generation of immunomodulatory biologics with better therapeutic efficacy, minimized adverse effects and long-lasting clinical benefit. The recent encouraging results from antibodies targeting programmed cell death protein 1 (PD1) and B7 homolog 1 (B7H1; also known as PDL1) for the treatment of various advanced human cancers show that immunomodulatory therapy has come of age. PMID:23370250

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

    Science.gov (United States)

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

    2014-04-01

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

  7. A duality result between the minimal surface equation and the maximal surface equation

    Directory of Open Access Journals (Sweden)

    ALÍAS LUIS J.

    2001-01-01

    Full Text Available In this note we show how classical Bernstein's theorem on minimal surfaces in the Euclidean space can be seen as a consequence of Calabi-Bernstein's theorem on maximal surfaces in the Lorentz-Minkowski space (and viceversa. This follows from a simple but nice duality between solutions to their corresponding differential equations.

  8. Heat-transfer-method-based cell culture quality assay through cell detection by surface imprinted polymers.

    Science.gov (United States)

    Eersels, Kasper; van Grinsven, Bart; Khorshid, Mehran; Somers, Veerle; Püttmann, Christiane; Stein, Christoph; Barth, Stefan; Diliën, Hanne; Bos, Gerard M J; Germeraad, Wilfred T V; Cleij, Thomas J; Thoelen, Ronald; De Ceuninck, Ward; Wagner, Patrick

    2015-02-17

    Previous work has indicated that surface imprinted polymers (SIPs) allow for highly specific cell detection through macromolecular cell imprints. The combination of SIPs with a heat-transfer-based read-out technique has led to the development of a selective, label-free, low-cost, and user-friendly cell detection assay. In this study, the breast cancer cell line ZR-75-1 is used to assess the potential of the platform for monitoring the quality of a cell culture in time. For this purpose, we show that the proposed methodology is able to discriminate between the original cell line (adherent growth, ZR-75-1a) and a descendant cell line (suspension growth, ZR-75-1s). Moreover, ZR-75-1a cells were cultured for a prolonged period of time and analyzed using the heat-transfer method (HTM) at regular time intervals. The results of these experiments demonstrate that the thermal resistance (Rth) signal decays after a certain number of cell culture passages. This can likely be attributed to a compromised quality of the cell culture due to cross-contamination with the ZR-75-1s cell line, a finding that was confirmed by classical STR DNA profiling. The cells do not express the same functional groups on their membrane, resulting in a weaker bond between cell and imprint, enabling cell removal by mechanical friction, provided by flushing the measuring chamber with buffer solution. These findings were further confirmed by HTM and illustrate that the biomimetic sensor platform can be used as an assay for monitoring the quality of cell cultures in time.

  9. Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Preliminary Evaluation Results

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, K.; Eudy, L.

    2008-10-01

    This report provides preliminary results from a National Renewable Energy Laboratory evaluation of a protoptye fuel cell transit bus operating at Connecticut Transit in Hartford. Included are descriptions of the planned fuel cell bus demonstration and equipment; early results and agency experience are also provided.

  10. Cell surface and transcriptional characterization of human adipose-derived adherent stromal (hADAS) cells.

    Science.gov (United States)

    Katz, Adam J; Tholpady, Ashok; Tholpady, Sunil S; Shang, Hulan; Ogle, Roy C

    2005-03-01

    Adult human subcutaneous adipose tissue contains cells with intriguing multilineage developmental plasticity, much like marrow-derived mesenchymal stem cells. Putative stem or progenitor cells from fat have been given many different names in the literature, reflecting an early and evolving consensus regarding their phenotypic characterization. The study reported here used microarrays to evaluate over 170 genes relating to angiogenesis and extracellular matrix in undifferentiated, early-passage human adipose-derived adherent stromal (hADAS) cells isolated from three separate donors. The hADAS populations unanimously transcribed 66% of the screened genes, and 83% were transcribed by at least two of the three populations. The most highly transcribed genes relate to functional groupings such as cell adhesion, matrix proteins, growth factors and receptors, and proteases. The transcriptome of hADAS cells demonstrated by this work reveals many similarities to published profiles of bone marrow mesenchymal stem cells (MSCs). In addition, flow analysis of over 24 hADAS cell surface proteins (n = 7 donors) both confirms and expands on the existing literature and reveals strong intergroup correlation, despite an inconsistent nomenclature and the lack of standardized protocols for cell isolation and culture. Finally, based on flow analysis and reverse transcription polymerase chain reaction studies, our results suggest that hADAS cells do not express several proteins that are implicated as markers of "stemness" in other stem cell populations, including telomerase, CD133, and the membrane transporter ABCG2.

  11. Controlling cell adhesion via replication of laser micro/nano-textured surfaces on polymers

    International Nuclear Information System (INIS)

    The aim of this study is to investigate cell adhesion and viability on highly rough polymeric surfaces with gradient roughness ratios and wettabilities prepared by microreplication of laser micro/nano-textured Si surfaces. Negative replicas on polydimethylsiloxane as well as positive ones on a photocurable (organically modified ceramic) and a biodegradable (poly(lactide-co-glycolide)) polymer have been successfully reproduced. The final culture substrates comprised from forests of micron-sized conical spikes exhibiting a range of roughness ratios and wettabilities, was achieved by changing the laser fluence used to fabricate the original template surfaces. Cell culture experiments were performed with the fibroblast NIH/3T3 and PC12 neuronal cell lines in order to investigate how these surfaces are capable of modulating different types of cellular responses including, viability, adhesion and morphology. The results showed a preferential adhesion of both cell types on the microstructured surfaces compared to the unstructured ones. In particular, the fibroblast NIH/3T3 cells show optimal adhesion for small roughness ratios, independent of the surface wettability and polymer type, indicating a non-monotonic dependence of cell adhesion on surface energy. In contrast, the PC12 cells were observed to adhere well to the patterned surfaces independent of the roughness ratio and wettability. These experimental findings are correlated with micromechanical measurements performed on the unstructured and replicated surfaces and discussed on the basis of previous observations describing the relation of cell response to surface energy and rigidity.

  12. Controlling cell adhesion via replication of laser micro/nano-textured surfaces on polymers

    Energy Technology Data Exchange (ETDEWEB)

    Koufaki, Niki; Ranella, Anthi; Barberoglou, Marios; Psycharakis, Stylianos; Fotakis, Costas; Stratakis, Emmanuel [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete (Greece); Aifantis, Katerina E, E-mail: stratak@iesl.forth.gr [Lab of Mechanics and Materials, Aristotle University of Thessaloniki, Thessaloniki (Greece)

    2011-12-15

    The aim of this study is to investigate cell adhesion and viability on highly rough polymeric surfaces with gradient roughness ratios and wettabilities prepared by microreplication of laser micro/nano-textured Si surfaces. Negative replicas on polydimethylsiloxane as well as positive ones on a photocurable (organically modified ceramic) and a biodegradable (poly(lactide-co-glycolide)) polymer have been successfully reproduced. The final culture substrates comprised from forests of micron-sized conical spikes exhibiting a range of roughness ratios and wettabilities, was achieved by changing the laser fluence used to fabricate the original template surfaces. Cell culture experiments were performed with the fibroblast NIH/3T3 and PC12 neuronal cell lines in order to investigate how these surfaces are capable of modulating different types of cellular responses including, viability, adhesion and morphology. The results showed a preferential adhesion of both cell types on the microstructured surfaces compared to the unstructured ones. In particular, the fibroblast NIH/3T3 cells show optimal adhesion for small roughness ratios, independent of the surface wettability and polymer type, indicating a non-monotonic dependence of cell adhesion on surface energy. In contrast, the PC12 cells were observed to adhere well to the patterned surfaces independent of the roughness ratio and wettability. These experimental findings are correlated with micromechanical measurements performed on the unstructured and replicated surfaces and discussed on the basis of previous observations describing the relation of cell response to surface energy and rigidity.

  13. Microplicae: specialized surface structure of epithelial cells of wet-surfaced oral mucosa

    NARCIS (Netherlands)

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

    2015-01-01

    The surface structure of the superficial cells of the oral mucosa is decorated with numerous membrane ridges, termed microplicae (MPLs). The MPL structure is typical of the epithelial surfaces that are covered with protective mucus. Cell membrane MPLs are no longer seen as passive consequences of ce

  14. RPE cell surface proteins in normal and dystrophic rats

    International Nuclear Information System (INIS)

    Membrane-bound proteins in plasma membrane enriched fractions from cultured rat RPE were analyzed by two-dimensional gel electrophoresis. Membrane proteins were characterized on three increasingly specific levels. Total protein was visualized by silver staining. A maximum of 102 separate proteins were counted in silver-stained gels. Glycoproteins were labeled with 3H-glucosamine or 3H-fucose and detected by autoradiography. Thirty-eight fucose-labeled and 61-71 glucosamine-labeled proteins were identified. All of the fucose-labeled proteins were labeled with glucosamine-derived radioactivity. Proteins exposed at the cell surface were labeled by lactoperoxidase-catalyzed radioiodination prior to preparation of membranes for two-dimensional analysis. Forty separate 125I-labeled surface proteins were resolved by two-dimensional electrophoresis/autoradiography. Comparison with the glycoprotein map showed that a number of these surface labeled proteins were glycoproteins. Two-dimensional maps of total protein, fucose-labeled, and glucosamine-labeled glycoproteins, and 125I-labeled surface proteins of membranes from dystrophic (RCS rdy-p+) and normal (Long Evans or RCS rdy+p+) RPE were compared. No differences in the total protein or surface-labeled proteins were observed. However, the results suggest that a 183K glycoprotein is more heavily glycosylated with glucosamine and fucose in normal RPE membranes as compared to membranes from dystrophic RPE

  15. RPE cell surface proteins in normal and dystrophic rats

    Energy Technology Data Exchange (ETDEWEB)

    Clark, V.M.; Hall, M.O.

    1986-02-01

    Membrane-bound proteins in plasma membrane enriched fractions from cultured rat RPE were analyzed by two-dimensional gel electrophoresis. Membrane proteins were characterized on three increasingly specific levels. Total protein was visualized by silver staining. A maximum of 102 separate proteins were counted in silver-stained gels. Glycoproteins were labeled with 3H-glucosamine or 3H-fucose and detected by autoradiography. Thirty-eight fucose-labeled and 61-71 glucosamine-labeled proteins were identified. All of the fucose-labeled proteins were labeled with glucosamine-derived radioactivity. Proteins exposed at the cell surface were labeled by lactoperoxidase-catalyzed radioiodination prior to preparation of membranes for two-dimensional analysis. Forty separate 125I-labeled surface proteins were resolved by two-dimensional electrophoresis/autoradiography. Comparison with the glycoprotein map showed that a number of these surface labeled proteins were glycoproteins. Two-dimensional maps of total protein, fucose-labeled, and glucosamine-labeled glycoproteins, and 125I-labeled surface proteins of membranes from dystrophic (RCS rdy-p+) and normal (Long Evans or RCS rdy+p+) RPE were compared. No differences in the total protein or surface-labeled proteins were observed. However, the results suggest that a 183K glycoprotein is more heavily glycosylated with glucosamine and fucose in normal RPE membranes as compared to membranes from dystrophic RPE.

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

    Science.gov (United States)

    Szczupak, Alon; Alfonta, Lital

    2015-01-01

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

  17. PROTEIN ADSORPTION AND CELL ADHESION ON RGD-FUNCTIONALIZED SILICON SUBSTRATE SURFACES

    Institute of Scientific and Technical Information of China (English)

    Wei-fang Tong; Xiao-li Liu; Fei Pan; Zhao-qiang Wu; Wen-wen Jiang

    2013-01-01

    A method was developed to modify silicon surfaces with good protein resistance and specific cell attachment.A silicon surface was initially deposited using a block copolymer of N-vinylpyrrolidone (NVP) and 2-hydroxyethyl methacrylate (HEMA) (PVP-b-PHEMA) film through surface-initiated atom transfer radical polymerization and then further immobilized using a short arginine-glycine-aspartate (RGD) peptide.Our results demonstrate that the RGD-modified surfaces (Si-RGD) can suppress non-specific adsorption of proteins and induce the adhesion of L929 cells.The Si-RGD surface exhibited higher cell proliferation rates than the unmodified silicon surface.This research established a simple method for the fabrication of dual-functional silicon surface that combines antifouling and cell attachment promotion.

  18. Tracking Traction Force Changes of Single Cells on the Liquid Crystal Surface

    Directory of Open Access Journals (Sweden)

    Chin Fhong Soon

    2015-01-01

    Full Text Available Cell migration is a key contributor to wound repair. This study presents findings indicating that the liquid crystal based cell traction force transducer (LCTFT system can be used in conjunction with a bespoke cell traction force mapping (CTFM software to monitor cell/surface traction forces from quiescent state in real time. In this study, time-lapse photo microscopy allowed cell induced deformations in liquid crystal coated substrates to be monitored and analyzed. The results indicated that the system could be used to monitor the generation of cell/surface forces in an initially quiescent cell, as it migrated over the culture substrate, via multiple points of contact between the cell and the surface. Future application of this system is the real-time assaying of the pharmacological effects of cytokines on the mechanics of cell migration.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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. Surface-modified gold nanorods for specific cell targeting

    Science.gov (United States)

    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. Solitary wave propagation in surface stabilized ferroelectric liquid crystal cells

    OpenAIRE

    VIJ, JAGDISH; Song, Jang-Kun

    2008-01-01

    PUBLISHED Solitary wave propagation in surface stabilized ferroelectric liquid crystal cells controlled by surface anchoring of the alignment layers is investigated for different conditions of alignment on the two opposite surfaces. We show that the critical field Ec, where the speed of the solitary wave becomes zero, is finite for asymmetric alignment on two surfaces. We also show that the polar anchoring energy difference (Deltawp) between the alignment layers can be calculated by measur...

  3. Fluid dynamics and noise in bacterial cell-cell and cell-surface scattering

    CERN Document Server

    Drescher, Knut; Cisneros, Luis H; Ganguly, Sujoy; Goldstein, Raymond E; 10.1073/pnas.1019079108

    2011-01-01

    Bacterial processes ranging from gene expression to motility and biofilm formation are constantly challenged by internal and external noise. While the importance of stochastic fluctuations has been appreciated for chemotaxis, it is currently believed that deterministic long-range fluid dynamical effects govern cell-cell and cell-surface scattering - the elementary events that lead to swarming and collective swimming in active suspensions and to the formation of biofilms. Here, we report the first direct measurements of the bacterial flow field generated by individual swimming Escherichia coli both far from and near to a solid surface. These experiments allowed us to examine the relative importance of fluid dynamics and rotational diffusion for bacteria. For cell-cell interactions it is shown that thermal and intrinsic stochasticity drown the effects of long-range fluid dynamics, implying that physical interactions between bacteria are determined by steric collisions and near-field lubrication forces. This dom...

  4. Hydrophobic fractal surface from glycerol tripalmitate and the effects on C6 glioma cell growth.

    Science.gov (United States)

    Zhang, Shanshan; Chen, Xuerui; Yu, Jing; Hong, Biyuan; Lei, Qunfang; Fang, Wenjun

    2016-06-01

    To provide a biomimic environment for glial cell culture, glycerol tripalmitate (PPP) has been used as a raw material to prepare fractal surfaces with different degrees of hydrophobicity. The spontaneous formation of the hydrophobic fractal surfaces was monitored by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The surface morphologies were observed by a scanning electron microscope (SEM), and then the fractal dimension (FD) values of the surfaces were determined with the box-counting method. C6 glioma cells were cultured and compared on different hydrophobic PPP surfaces and poly-L-lysine (PLL)-coated surface. The cell numbers as a function of incubation time on different surfaces during the cell proliferation process were measured, and the cell morphologies were observed under a fluorescence microscope. Influences of hydrophobic fractal surfaces on the cell number and morphology were analyzed. The experimental results show that the cell proliferation rates decrease while the cell morphology complexities increase with the growth of the fractal dimensions of the PPP surfaces. PMID:26970826

  5. Interaction of Epithelial Cells with Surfaces and Surfaces Decorated by Molecules

    CERN Document Server

    Martini, Daniele; Beil, Michael; Paust, T; Huang, C; Moosmann, M; Jin, J; Heiler, T; Gröger, R; Schimmel, Thomas; Walheim, Stefan

    2013-01-01

    A detailed understanding of the interface between living cells and substrate materials is of rising importance in many fields of medicine, biology and biotechnology. Cells at interfaces often form epithelia. The physical barrier that they form is one of their main functions. It is governed by the properties of the networks forming the cytoskeleton systems and by cell-to-cell contacts. Different substrates with varying surface properties modify the migration velocity of the cells. On the one hand one can change the materials composition. Organic and inorganic materials induce differing migration velocities in the same cell system. Within the same class of materials, a change of the surface stiffness or of the surface energy modifies the migration velocity, too. For our cell adhesion studies a variety of different, homogeneous substrates were used (polymers, bio-polymers, metals, oxides). In addition, an effective lithographic method, Polymer Blend Lithography (PBL), is reported, to produce patterned Self-Assem...

  6. Increasing binding density of yeast cells by control of surface charge with allylamine grafting to ion modified polymer surfaces.

    Science.gov (United States)

    Tran, Clara T H; Kondyurin, Alexey; Chrzanowski, Wojciech; Bilek, Marcela M M; McKenzie, David R

    2014-10-01

    Plasma immersion ion implantation (PIII) treatment of polymers creates a biointerface capable of direct covalent immobilization of biomolecules. The immobilization of protein molecules is achieved by covalent bonds formed between embedded radicals on the treated surface and amino acid side chains and cells can be immobilized through cell-wall proteins. The attachment density of negatively charged entities on a PIII treated surface is inhibited by its negative surface charge at neutral pH. To reduce the negative charge of PIII treated surfaces in phosphate buffer (pH 7.4, 11mM), we develop an effective approach of grafting allylamine monomers onto the treated surface. The results reveal reactions between allylamine and radicals on the PIII treated surface. One of these triggers polymerization, increasing the number of amine groups grafted. As a consequence, the PIII treated polystyrene surface after allylamine exposure becomes more hydrophobic and less negatively charged in phosphate buffer. Using yeast cells as an example, we have shown a significant improvement (6-15 times) of cell density immobilized on the PIII treated surface after exposure to allylamine. PMID:25092587

  7. [Results of mammalian cell culture exposure on artificial earth satellites].

    Science.gov (United States)

    Sushkov, F V; Portugalov, V V; Rudneva, S V; Bobkova, N N; Iordanishvili, E K

    1976-01-01

    The paper presents the results of an exposure of cells of the Syrian hamster strain VNK-21 to space flight effects. In contrast to the cell culture kept in a thermostat at 29 degrees C, the cell culture that was maintained in thermally uncontrolled conditions developed noticeable structural and physiological changes induced by suboptimal temperatures. It was concluded that a 6-day exposure to weightlessness exerted no adverse effect on mammalian cells in vitro and produced no stable structural or physiological changes. Some changes that were detected in the cell culture--faster ageing, stable tendency to an increase of the number of cells with enlarged nuclei, an increase of the mitotic index at an early stage of cultivation--need further investigation.

  8. Mechanotransduction Across the Cell Surface and Through the Cytoskeleton

    Science.gov (United States)

    Wang, Ning; Butler, James P.; Ingber, Donald E.

    1993-05-01

    Mechanical stresses were applied directly to cell surface receptors with a magnetic twisting device. The extracellular matrix receptor, integrin β_1, induced focal adhesion formation and supported a force-dependent stiffening response, whereas nonadhesion receptors did not. The cytoskeletal stiffness (ratio of stress to strain) increased in direct proportion to the applied stress and required intact microtubules and intermediate filaments as well as microfilaments. Tensegrity models that incorporate mechanically interdependent struts and strings that reorient globally in response to a localized stress mimicked this response. These results suggest that integrins act as mechanoreceptors and transmit mechanical signals to the cytoskeleton. Mechanotransduction, in turn, may be mediated simultaneously at multiple locations inside the cell through force-induced rearrangements within a tensionally integrated cytoskeleton.

  9. Surface Plasmon Resonance for Cell-Based Clinical Diagnosis

    Directory of Open Access Journals (Sweden)

    Yuhki Yanase

    2014-03-01

    Full Text Available 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.

  10. Cell surface glycan alterations in epithelial mesenchymal transition process of Huh7 hepatocellular carcinoma cell.

    Directory of Open Access Journals (Sweden)

    Shan Li

    Full Text Available BACKGROUND AND OBJECTIVE: Due to recurrence and metastasis, the mortality of Hepatocellular carcinoma (HCC is high. It is well known that the epithelial mesenchymal transition (EMT and glycan of cell surface glycoproteins play pivotal roles in tumor metastasis. The goal of this study was to identify HCC metastasis related differential glycan pattern and their enzymatic basis using a HGF induced EMT model. METHODOLOGY: HGF was used to induce HCC EMT model. Lectin microarray was used to detect the expression of cell surface glycan and the difference was validated by lectin blot and fluorescence cell lectin-immunochemistry. The mRNA expression levels of glycotransferases were determined by qRT-PCR. RESULTS: After HGF treatment, the Huh7 cell lost epithelial characteristics and obtained mesenchymal markers. These changes demonstrated that HGF could induce a typical cell model of EMT. Lectin microarray analysis identified a decreased affinity in seven lectins ACL, BPL, JAC, MPL, PHA-E, SNA, and SBA to the glycan of cell surface glycoproteins. This implied that glycan containing T/Tn-antigen, NA2 and bisecting GlcNAc, Siaα2-6Gal/GalNAc, terminal α or βGalNAc structures were reduced. The binding ability of thirteen lectins, AAL, LCA, LTL, ConA, NML, NPL, DBA, HAL, PTL II, WFL, ECL, GSL II and PHA-L to glycan were elevated, and a definite indication that glycan containing terminal αFuc and ± Sia-Le, core fucose, α-man, gal-β(α GalNAc, β1,6 GlcNAc branching and tetraantennary complex oligosaccharides structures were increased. These results were further validated by lectin blot and fluorescence cell lectin-immunochemistry. Furthermore, the mRNA expression level of Mgat3 decreased while that of Mgat5, FucT8 and β3GalT5 increased. Therefore, cell surface glycan alterations in the EMT process may coincide with the expression of glycosyltransferase. CONCLUSIONS: The findings of this study systematically clarify the alterations of cell surface

  11. Surface Passivation Studies on n+pp+ Bifacial Solar Cell

    OpenAIRE

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

    2012-01-01

    Bifacial solar cell is a specially designed solar cell for the production of electricity from both sides of the solar cell. It is an active field of research to make photovoltaics (PV) more competitive by increasing its efficiency and lowering its costs. We developed an n+pp+ structure for the bifacial solar cell. The fabrication used phosphorus-oxy-trichloride (POCl3) diffusion to form the emitter and Al diffusion using conventional screen printing to produce the back surface field (BSF). Th...

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

    Science.gov (United States)

    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.

  13. Ancestral vascular lumen formation via basal cell surfaces.

    Directory of Open Access Journals (Sweden)

    Tomás Kucera

    Full Text Available The cardiovascular system of bilaterians developed from a common ancestor. However, no endothelial cells exist in invertebrates demonstrating that primitive cardiovascular tubes do not require this vertebrate-specific cell type in order to form. This raises the question of how cardiovascular tubes form in invertebrates? Here we discovered that in the invertebrate cephalochordate amphioxus, the basement membranes of endoderm and mesoderm line the lumen of the major vessels, namely aorta and heart. During amphioxus development a laminin-containing extracellular matrix (ECM was found to fill the space between the basal cell surfaces of endoderm and mesoderm along their anterior-posterior (A-P axes. Blood cells appear in this ECM-filled tubular space, coincident with the development of a vascular lumen. To get insight into the underlying cellular mechanism, we induced vessels in vitro with a cell polarity similar to the vessels of amphioxus. We show that basal cell surfaces can form a vascular lumen filled with ECM, and that phagocytotic blood cells can clear this luminal ECM to generate a patent vascular lumen. Therefore, our experiments suggest a mechanism of blood vessel formation via basal cell surfaces in amphioxus and possibly in other invertebrates that do not have any endothelial cells. In addition, a comparison between amphioxus and mouse shows that endothelial cells physically separate the basement membranes from the vascular lumen, suggesting that endothelial cells create cardiovascular tubes with a cell polarity of epithelial tubes in vertebrates and mammals.

  14. Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Alan M. [School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH (United Kingdom); Paxton, Jennifer Z.; Hung, Yi-Pei; Hadley, Martin J.; Bowen, James; Williams, Richard L. [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom); Grover, Liam M., E-mail: l.m.grover@bham.ac.uk [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom)

    2015-03-01

    Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40 years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation. - Highlights: • Crystallinity of HA at the nano-scale was dominant over macro-scale topography. • Lower crystallinity caused rapid cell attachment and proliferation rate. • Crystallinity could be easily adjusted by without compromising coating purity.

  15. VUV treatment combined with mechanical strain of stretchable polymer foils resulting in cell alignment

    Energy Technology Data Exchange (ETDEWEB)

    Barb, R.-A. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Magnus, B. [Innovacell Biotechnologie AG, Innsbruck (Austria); Innerbichler, S. [Innerbichler GmbH, Breitenbach am Inn (Austria); Greunz, T. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Wiesbauer, M. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Marksteiner, R. [Innovacell Biotechnologie AG, Innsbruck (Austria); Stifter, D. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Heitz, J., E-mail: johannes.heitz@jku.at [Institute of Applied Physics, Johannes Kepler University Linz (Austria)

    2015-01-15

    Highlights: • Elastic polyurethane (PU) foils were exposed to the vacuum-UV in reactive atmosphere. • The photomodification resulted in improved cytocompatibilty. • Parallel microgrooves formed on the irradiated PU surfaces after strong elongation. • Cells seeded onto microgrooves aligned their shapes in the direction of the grooves. • Elongation occurred also for cells on PU subjected to cyclic mechanical stretching. - Abstract: Cell-alignment along a defined direction can have a direct effect on the cell functionality and differentiation. Oriented micro- or nanotopographic structures on cell culture substrates can induce cell-alignment. Surface chemistry, wettability, and stiffness of the substrate are also important material features as they strongly influence the cell–substrate interactions. For improved bio-compatibility, highly elastic polyurethane (PU) foils were exposed to the vacuum-UV (VUV) light of a Xe{sub 2}{sup *} excimer lamp at 172 nm in a nitrogen containing atmosphere (N{sub 2} or NH{sub 3}). The irradiation resulted in a change in the chemical surface composition. Additionally, the formation of regular parallel microgrooves was observed on the irradiated surfaces after strong uni-axial deformation (i.e., more than about 50% strain) of the photo-modified PU foils. Cell seeding experiments demonstrated that the VUV modified polymer foils strongly enhance cell adhesion and proliferation. Cells seeded onto microgrooves aligned their shapes and elongated in the direction of the grooves. A similar effect was observed for cells seeded on photo-modified PU foils subjected to cyclic mechanical stretching at lower strain levels (i.e., typically 10% strain) without groove-formation. The cells had also here an elongated shape, however they not always align in a defined direction relative to the stretching.

  16. Cell Surface Enzymatic Engineering-Based Approaches to Improve Cellular Therapies

    KAUST Repository

    Abuelela, Ayman F.

    2014-06-06

    The cell surface represents the interface between the cell and its environment. As such, the cell surface controls cell–cell interactions and functions such as adhesion and migration, and will transfer external cues to regulate processes such as survival, death, and differentiation. Redefining the cell surface by temporarily (or permanently) modifying the molecular landscape of the plasma membrane affects the way in which the cell interacts with its environment and influences the information that is relayed into the cell along downstream signaling pathways. This chapter outlines the role of key enzymes, the glycosyltransferases, in posttranslationally modifying proteins and lipids to fine-tune cells, ability to migrate. These enzymes are critical in controlling the formation of a platform structure, sialyl Lewis x (sLex), on circulating cells that plays a central role in the recognition and recruitment by selectin counter receptors on endothelial cells that line blood vessels of tissues throughout the body. By developing methods to manipulate the activity of these enzymes and hence the cell surface structures that result, treatments can be envisioned that direct the migration of therapeutic cells to specific locations throughout the body and also to inhibit metastasis of detrimental cells such as circulating tumor cells.

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

    Science.gov (United States)

    Tanaka, Tsutomu; Kondo, Akihiko

    2015-11-15

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

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

    Science.gov (United States)

    Tanaka, Tsutomu; Kondo, Akihiko

    2015-11-15

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

  19. Cell surface carbohydrates as prognostic markers in human carcinomas

    DEFF Research Database (Denmark)

    Dabelsteen, Erik

    1996-01-01

    Tumour development is usually associated with changes in cell surface carbohydrates. These are often divided into changes related to terminal carbohydrate structures, which include incomplete synthesis and modification of normally existing carbohydrates, and changes in the carbohydrate core struc...

  20. Surface Properties of Cell-treated Polyethylene Terephthalate

    Directory of Open Access Journals (Sweden)

    Bing Shi

    2006-01-01

    Full Text Available The materials used in artificial joints undergo degradation through fatigue and corrosive wear in human body. The lifetime for well-designed artificial joints like hip joints is at most 12 years and a patient will usually have two total joint replacements during his/her lifetime. Tissue engineering, an alternative to total joint implantation, is the replacement of damaged tissue with the tissue that is designed and constructed to meet the needs of the individual patient. In this study, polyethylene terephthalate (PET in the form of overhead transparency films were investigated on their cell interactions and the tribological properties as an alternative tissue-engineering matrix. The base material of the transparency films is PET. Cell culture methods as well as atomic force microscope (AFM, contact angle goniometer, confocal microscope and universal tribotester were used to study the properties of the substrate materials and the interactions between the surface and the substrate materials. Results showed that cells grew on the substrate of the base materials of the PET. The tribological properties of the slides have been changed after being cell-treated.

  1. Surface texturing of multicrystalline silicon solar cells

    OpenAIRE

    L.A. Dobrzański; A. Drygała

    2008-01-01

    Purpose: The aim of the paper is to elaborate a laser method of texturization multicrystalline silicon. The main reason for taking up the research is that most conventional methods used for texturization of monocrystalline silicon are ineffective when applied for texturing multicrystalline silicon. This is related to random distribution of grains of different crystalographic orientations on the surface of multicrystalline silicon.Design/methodology/approach: The topography of laser ...

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Dongfeng Chen

    Full Text Available 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

  4. Cell orientation on a stripe-micropatterned surface

    Institute of Scientific and Technical Information of China (English)

    SUN JianGuo; TANG Jian; DING JianDong

    2009-01-01

    Stripe-micropatterned surfaces have recently been a unique tool to study cell orientation. In this paper,we prepared,by the photolithography transfer technique,stable gold (Au) micropatterns on PEG hydrogel surfaces with defined cell-resistant (PEG hydrogel) and cell-adhesive (gold microstripes) proparties. 3T3 fibroblasts were cultured on Au-microstripe surfaces to observe cell adhesion and orientation. Five statistical parameters were defined and used to describe cell orientation on micropatterns.With the increase of inter-stripe distance,the orientational order parameter,the ratio of long and short axes of a cell,and the occupation fraction of cells on stripes increased gradually,whereas the spreading area of a single cell decreased. The abrupt changes of these four parameters did not happen at the same inter-distance. The adhesion ratio of a cell on Au stripes over cell spreading area did not change monotonically as a function of inter-stripe distance. The combination of the 5 statistical parameters represented well the cell orientation behaviors semi-quantitatively.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  7. Cell surface localization and tissue distribution of a hepatocyte cell-cell adhesion glycoprotein (cell-CAM 105)

    OpenAIRE

    Ocklind, C; Forsum, U; Obrink, B

    1983-01-01

    We recently identified a 105,000-dalton plasma membrane glycoprotein, denoted cell-CAM 105 (CAM, cell adhesion molecule), that is involved in intercellular adhesion of reaggregating rat hepatocytes (Ocklind, C., and B. Obrink, 1982, J. Biol. Chem., 257:6788-6795). In this communication we used a monospecific rabbit antiserum against cell-CAM 105 to localize the antigen by indirect immunofluorescence on isolated rat cells and on frozen rat tissue sections. This antiserum stained the surface of...

  8. Immobilized cell technology in beer brewing: Current experience and results

    Directory of Open Access Journals (Sweden)

    Leskošek-Čukalov Ida J.

    2005-01-01

    Full Text Available Immobilized cell technology (ICT has been attracting continual attention in the brewing industry over the past 30 years. Some of the reasons are: faster fermentation rates and increased volumetric productivity, compared to those of traditional beer production based on freely suspended cells, as well as the possibility of continuous operation. Nowadays, ICT technology is well established in secondary fermentation and alcohol- free and low-alcohol beer production. In main fermentation, the situation is more complex and this process is still under scrutiny on both the lab and pilot levels. The paper outlines the most important ICT processes developed for beer brewing and provides an overview of carrier materials, bioreactor design and examples of their industrial applications, as well as some recent results obtained by our research group. We investigated the possible applications of polyvinyl alcohol in the form of LentiKats®, as a potential porous matrices carrier for beer fermentation. Given are the results of growth studies of immobilized brewer's yeast Saccharomyces uvarum and the kinetic parameters obtained by using alginate microbeads with immobilized yeast cells and suspension of yeast cells as controls. The results indicate that the immobilization procedure in LentiKat® carriers has a negligible effect on cell viability and growth. The apparent specific growth rate of cells released in medium was comparable to that of freely suspended cells, implying preserved cell vitality. A series of batch fermentations performed in shaken flasks and an air-lift bioreactor indicated that the immobilized cells retained high fermentation activity. The full attenuation in green beer was reached after 48 hours in shaken flasks and less than 24 hours of fermentation in gas-lift bioreactors.

  9. Microfluidic single-cell transcriptional analysis rationally identifies novel surface marker profiles to enhance cell-based therapies.

    Science.gov (United States)

    Rennert, Robert C; Januszyk, Michael; Sorkin, Michael; Rodrigues, Melanie; Maan, Zeshaan N; Duscher, Dominik; Whittam, Alexander J; Kosaraju, Revanth; Chung, Michael T; Paik, Kevin; Li, Alexander Y; Findlay, Michael; Glotzbach, Jason P; Butte, Atul J; Gurtner, Geoffrey C

    2016-01-01

    Current progenitor cell therapies have only modest efficacy, which has limited their clinical adoption. This may be the result of a cellular heterogeneity that decreases the number of functional progenitors delivered to diseased tissue, and prevents correction of underlying pathologic cell population disruptions. Here, we develop a high-resolution method of identifying phenotypically distinct progenitor cell subpopulations via single-cell transcriptional analysis and advanced bioinformatics. When combined with high-throughput cell surface marker screening, this approach facilitates the rational selection of surface markers for prospective isolation of cell subpopulations with desired transcriptional profiles. We establish the usefulness of this platform in costly and highly morbid diabetic wounds by identifying a subpopulation of progenitor cells that is dysfunctional in the diabetic state, and normalizes diabetic wound healing rates following allogeneic application. We believe this work presents a logical framework for the development of targeted cell therapies that can be customized to any clinical application. PMID:27324848

  10. Immunogold labels: cell-surface markers in atomic force microscopy

    NARCIS (Netherlands)

    Putman, Constant A.J.; Grooth, de Bart G.; Hansma, Paul K.; Hulst, van Niek F.; Greve, Jan

    1993-01-01

    The feasibility of using immunogold labels as cell-surface markers in atomic force microscopy is shown in this paper. The atomic force microscope (AFM) was used to image the surface of immunogold-labeled human lymphocytes. The lymphocytes were isolated from whole blood and labeled by an indirect imm

  11. Expanding the diversity of unnatural cell surface sialic acids

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  13. Cell-surface glycoproteins of human sarcomas: differential expression in normal and malignant tissues and cultured cells

    Energy Technology Data Exchange (ETDEWEB)

    Rettig, W.F.; Garin-Chesa, P.; Beresford, H.R.; Oettgen, H.F.; Melamed, M.R.; Old, L.J.

    1988-05-01

    Normal differentiation and malignant transformation of human cells are characterized by specific changes in surface antigen phenotype. In the present study, the authors have defined six cell-surface antigens of human sarcomas and normal mesenchymal cells, by using mixed hemadsorption assays and immunochemical methods for the analysis of cultured cells and immunohistochemical staining for the analysis of normal tissues and > 200 tumor specimens. Differential patterns of F19, F24, G171, G253, S5, and Thy-1 antigen expression were found to characterize (i) subsets of cultured sarcoma cell lines, (ii) cultured fibroblasts derived from various organs, (iii) normal resting and activated mesenchymal tissues, and (iv) sarcoma and nonmesenchymal tumor tissues. These results provide a basic surface antigenic map for cultured mesenchymal cells and mesenchymal tissues and permit the classification of human sarcomas according to their antigenic phenotypes.

  14. Surface-engineered substrates for improved human pluripotent stem cell culture under fully defined conditions.

    Science.gov (United States)

    Saha, Krishanu; Mei, Ying; Reisterer, Colin M; Pyzocha, Neena Kenton; Yang, Jing; Muffat, Julien; Davies, Martyn C; Alexander, Morgan R; Langer, Robert; Anderson, Daniel G; Jaenisch, Rudolf

    2011-11-15

    The current gold standard for the culture of human pluripotent stem cells requires the use of a feeder layer of cells. Here, we develop a spatially defined culture system based on UV/ozone radiation modification of typical cell culture plastics to define a favorable surface environment for human pluripotent stem cell culture. Chemical and geometrical optimization of the surfaces enables control of early cell aggregation from fully dissociated cells, as predicted from a numerical model of cell migration, and results in significant increases in cell growth of undifferentiated cells. These chemically defined xeno-free substrates generate more than three times the number of cells than feeder-containing substrates per surface area. Further, reprogramming and typical gene-targeting protocols can be readily performed on these engineered surfaces. These substrates provide an attractive cell culture platform for the production of clinically relevant factor-free reprogrammed cells from patient tissue samples and facilitate the definition of standardized scale-up friendly methods for disease modeling and cell therapeutic applications.

  15. Surface-engineered substrates for improved human pluripotent stem cell culture under fully defined conditions.

    Science.gov (United States)

    Saha, Krishanu; Mei, Ying; Reisterer, Colin M; Pyzocha, Neena Kenton; Yang, Jing; Muffat, Julien; Davies, Martyn C; Alexander, Morgan R; Langer, Robert; Anderson, Daniel G; Jaenisch, Rudolf

    2011-11-15

    The current gold standard for the culture of human pluripotent stem cells requires the use of a feeder layer of cells. Here, we develop a spatially defined culture system based on UV/ozone radiation modification of typical cell culture plastics to define a favorable surface environment for human pluripotent stem cell culture. Chemical and geometrical optimization of the surfaces enables control of early cell aggregation from fully dissociated cells, as predicted from a numerical model of cell migration, and results in significant increases in cell growth of undifferentiated cells. These chemically defined xeno-free substrates generate more than three times the number of cells than feeder-containing substrates per surface area. Further, reprogramming and typical gene-targeting protocols can be readily performed on these engineered surfaces. These substrates provide an attractive cell culture platform for the production of clinically relevant factor-free reprogrammed cells from patient tissue samples and facilitate the definition of standardized scale-up friendly methods for disease modeling and cell therapeutic applications. PMID:22065768

  16. Study of surface cell Madelung constant and surface free energy of nanosized crystal grain

    Institute of Scientific and Technical Information of China (English)

    Zhang Wei-Jia; Wang Tian-Min; Rong Ai-Lun; Cui Min

    2006-01-01

    Surface cell Madelung constant is firstly defined for calculating the surface free energy of nanosized crystal grains,which explains the physical performance of small crystals and may be greatly beneficial to the analysis of surface states and the study of the dynamics of crystal nucleation and growth.A new approximative expression of the surface energy and relevant thermodynamic data are used in this calculation.New formula and computing method for calculating the Madelung constant α of any complex crystals are proposed,and the surface free energies and surface electrostatic energies of nanosized crystal grains and the Madelung constant of some complex crystals are theoretically calculated in this paper.The surface free energy of nanosized-crystal-grain TiO2 and the surface electrostatic energy (absolute value) of nanosized-crystal-grain α-A12O3 are found to be the biggest among all the crystal grains including those of other species.

  17. Study of Surface Cell Madelung Constant and Surface Free Energy of Nanosized Crystal Grain

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-Jia; WANG Tian-Min; CUI Min

    2005-01-01

    Surface cell Madelung constant is firstly defined in calculating surface free energy of nanosized crystal grains, which explains the physical performance of small crystals and may be great benefit to make surface analysis and study dynamics of crystal nucleus growth. A new ap- proximative expression of surface energy and relevant thermodynamic data was used in this cal- culation. A new formula and computing method for calculating the Madelung constant α of any complex crystals is proposed, and surface free energies and surface electrostatic energies of nano- sized crystal grains as well as Madelung constant of some complex crystals are theoretically cal- culated in this paper. The surface free energy of nanosized crystal grain TiO2 and surface elec- trostatic energy(absolute value) of nanosized crystal grain α-Al2O3 are found to be the biggest among other crystal grains.

  18. Surface expressed nucleolin is constantly induced in tumor cells to mediate calcium-dependent ligand internalization.

    Directory of Open Access Journals (Sweden)

    Ara G Hovanessian

    Full Text Available BACKGROUND: Nucleolin is one of the major proteins of the nucleolus, but it is also expressed on the cell surface where is serves as a binding protein for variety of ligands implicated in tumorigenesis and angiogenesis. Emerging evidence suggests that the cell-surface expressed nucleolin is a strategic target for an effective and nontoxic cancer therapy. METHODOLOGY/PRINCIPAL FINDINGS: By monitoring the expression of nucleolin mRNA, and by measuring the level of nucleolin protein recovered from the surface and nucleus of cells, here we show that the presence of nucleolin at the cell surface is dependent on the constant induction of nucleolin mRNA. Indeed, inhibitors of RNA transcription or translation block expression of surface nucleolin while no apparent effect is observed on the level of nucleolin in the nucleus. The estimated half-life of surface nucleolin is less than one hour, whereas that of nuclear nucleolin is more than 8 hours. Nucleolin mRNA induction is reduced markedly in normal fibroblasts that reach confluence, while it occurs continuously even in post-confluent epithelial tumor cells consistent with their capacity to proliferate without contact inhibition. Interestingly, cold and heat shock induce nucleolin mRNA concomitantly to enhanced mRNA expression of the heat shock protein 70, thus suggesting that surface nucleolin induction also occurs in response to an environmental insult. At the cell surface, one of the main functions of nucleolin is to shuttle specific extracellular ligands by an active transport mechanism, which we show here to be calcium dependent. CONCLUSION/SIGNIFICANCE: Our results demonstrate that the expression of surface nucleolin is an early metabolic event coupled with tumor cell proliferation and stress response. The fact that surface nucleolin is constantly and abundantly expressed on the surface of tumor cells, makes them a preferential target for the inhibitory action of anticancer agents that target

  19. Micro checkerboard patterned polymeric surface with discrete rigidity for studying cell migration

    International Nuclear Information System (INIS)

    The control of cell migration has an important role in processes ranging from developmental morphogenesis to the pathogenesis. In this study, we describe a novel approach to develop a micro-checkerboard patterned polymeric flat surface with discrete surface stiffness. This platform as a culture substrate allows us to explore the mechanism of durotaxis, referred to as the directed cell movement via the gradient of surface stiffness. The flat surface with different rigidity was achieved in two stages of fabrication. First, polydimethylsiloxane (PDMS) was pressed and cured on a glass substrate with trenches of varying depths in a checkerboard arrangement, and then, a thin PDMS layer was spin coated on the previous pattern to make the flat surface. The stiff region is defined by a thin layer (2.5 µm) of PDMS and the soft region is defined by a thick one (7.5 µm). To investigate the migratory cell behavior, the NIH 3T3 cell was cultured. The result demonstrates that a single cell showed clearly a migratory cell behavior toward the stiffer regions driven by the difference of effective surface stiffness. At high cell density, the effect of cell migration on effective surface stiffness decreased with increasing cell–cell interactions. However, cell migration was still dominated by difference of effective surface stiffness while fluctuating at the boundary between the stiff and soft regions. This approach enables us to control the mechanical and topological properties of surface. The developed platform will also offer a useful tool to study cell–substrate interaction mediated by surface stiffness (e.g. mechanotransduction). (paper)

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

    Science.gov (United States)

    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

  1. Femtosecond laser microstructuring of titanium surfaces for middle ear ossicular replacement prosthesis: results of preliminary studies

    Science.gov (United States)

    Biedron, S.; Ilgner, J. F. R.; Fadeeva, E.; Chichkov, B.; Prescher, A.; Bovi, M.; Westhofen, M.

    2009-07-01

    The objective of this study was to optimize titanium surfaces by means of Ti:Sapphire femtosecond laser to improve the attachment of human cartilage cells on titanium prosthesis in middle ear surgery. The application of microstructures on titanium samples was evaluated and the influence of these microstructures on human auricular chondrocytes was studied in-vitro. After establishing the ear chondrocyte cell culture, cells were seeded on titanium platelets with selected microstructure patterns. Whereas the phenotype of cells seeded on unstructured titanium was similar to cells grown on standard tissue culture surfaces, the morphology of chondrocytes grown on structured titanium samples was influenced by the pattern. For future titanium middle ear prosthesis structural optimizations will be developed to promote chondrocyte growth and adhesion while impeding fibrocyte proliferation to avoid scarring on implant interfaces.

  2. Cell shape and spreading of stromal (mesenchymal) stem cells cultured on fibronectin coated gold and hydroxyapatite surfaces

    DEFF Research Database (Denmark)

    Dolatshahi-Pirouz, A; Jensen, Thomas Hartvig Lindkjær; Kolind, Kristian;

    2011-01-01

    In order to identify the cellular mechanisms leading to the biocompatibility of hydroxyapatite implants, we studied the interaction of human bone marrow derived stromal (mesenchymal) stem cells (hMSCs) with fibronectin-coated gold (Au) and hydroxyapatite (HA) surfaces. The adsorption of fibronectin...... as compared to Au. Moreover, the results revealed that the morphology of cells cultured on fibronectin coated HA surfaces were less irregular. In summary we find that fibronectin adsorbs in a more activated state on the HA surfaces, resulting in a slightly different cellular response as compared...

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

    Science.gov (United States)

    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

  4. Estimating intercellular surface tension by laser-induced cell fusion

    International Nuclear Information System (INIS)

    Intercellular surface tension is a key variable in understanding cellular mechanics. However, conventional methods are not well suited for measuring the absolute magnitude of intercellular surface tension because these methods require determination of the effective viscosity of the whole cell, a quantity that is difficult to measure. In this study, we present a novel method for estimating the intercellular surface tension at single-cell resolution. This method exploits the cytoplasmic flow that accompanies laser-induced cell fusion when the pressure difference between cells is large. Because the cytoplasmic viscosity can be measured using well-established technology, this method can be used to estimate the absolute magnitudes of tension. We applied this method to two-cell-stage embryos of the nematode Caenorhabditis elegans and estimated the intercellular surface tension to be in the 30–90 µN m−1 range. Our estimate was in close agreement with cell–medium surface tensions measured at single-cell resolution. (communication)

  5. Investigation of human cell response to covalently attached RADA16-I peptide on silicon surfaces.

    Science.gov (United States)

    Shamsi, Fahimeh

    2016-09-01

    We described a modification of the ionic (RADARADARADARADA)(1) peptide or RADA16-I with 4-azidophenyl isothiocyanate via a specific and gentle reaction. The azidated peptide was covalently immobilized on an alkyne-terminated monolayer on Si(111) via the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction. Detailed characterization using Impedance spectroscopy (IS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy demonstrated high coverage of the RADA 16-I peptide on silicon surfaces. Scanning electron microscopy (SEM) and methyl tetrazole sulfate (MTS) assay were used to characterize the morphology and proliferation ability of human fibroblast cells on surfaces. Cell adhesion assay was performed to examine cell-substrate interactions. Significant differences in fibroblast cell morphology, adhesion, and viability were observed on the RADA16-I peptide modified surfaces compared to the control surfaces. These results may suggest a potential application of RADA16-I peptide modified surfaces in biomedical applications. PMID:27236098

  6. Thermal plasma treatment of cell-phone waste : preliminary result

    Energy Technology Data Exchange (ETDEWEB)

    Ruj, B. [Central Mechanical Engineering Research Inst., Durgapur (India). Thermal Engineering Group; Chang, J.S.; Li, O.L. [McMaster Univ., Hamilton, ON (Canada). Dept. of Engineering Physics; Pietsch, G. [RWTH Aachen Univ., Aachen (Germany)

    2010-07-01

    The cell phone is an indispensable service facilitator, however, the disposal and recycling of cell phones is a major problem. While the potential life span of a mobile phone, excluding batteries, is over 10 years, most of the users upgrade their phones approximately four times during this period. Cell phone waste is significantly more hazardous than many other municipal wastes as it contains thousands of components made of toxic chemicals and metals like lead, cadmium, chromium, mercury, polyvinyl chlorides (PVC), brominated flame retardants, beryllium, antimony and phthalates. Cell phones also use many expensive rare metals. Since cell phones are made up of plastics, metals, ceramics, and trace other substances, primitive recycling or disposal of cell phone waste to landfills and incinerators creates irreversible environmental damage by polluting water and soil, and contaminating air. In order to minimize releases into the environment and threat to human health, the disposal of cell phones needs to be managed in an environmentally friendly way. This paper discussed a safer method of reducing the generation of syngas and hydrocarbons and metal recovery through the treatment of cell phone wastes by a thermal plasma. The presentation discussed the experiment, with particular reference to sample preparation; experimental set-up; and results four samples with different experimental conditions. It was concluded that the plasma treatment of cell phone waste in reduced condition generates gaseous components such as hydrogen, carbon monoxide, and hydrocarbons which are combustible. Therefore, this system is an energy recovery system that contributes to resource conservation and reduction of climate change gases. 5 refs., 2 tabs., 2 figs.

  7. Tumor suppressor protein SMAR1 modulates the roughness of cell surface: combined AFM and SEM study

    Directory of Open Access Journals (Sweden)

    Mamgain Hitesh

    2009-10-01

    Full Text Available Abstract Background Imaging tools such as scanning electron microscope (SEM and atomic force microscope (AFM can be used to produce high-resolution topographic images of biomedical specimens and hence are well suited for imaging alterations in cell morphology. We have studied the correlation of SMAR1 expression with cell surface smoothness in cell lines as well as in different grades of human breast cancer and mouse tumor sections. Methods We validated knockdown and overexpression of SMAR1 using RT-PCR as well as Western blotting in human embryonic kidney (HEK 293, human breast cancer (MCF-7 and mouse melanoma (B16F1 cell lines. The samples were then processed for cell surface roughness studies using atomic force microscopy (AFM and scanning electron microscopy (SEM. The same samples were used for microarray analysis as well. Tumors sections from control and SMAR1 treated mice as well as tissues sections from different grades of human breast cancer on poly L-lysine coated slides were used for AFM and SEM studies. Results Tumor sections from mice injected with melanoma cells showed pronounced surface roughness. In contrast, tumor sections obtained from nude mice that were first injected with melanoma cells followed by repeated injections of SMAR1-P44 peptide, exhibited relatively smoother surface profile. Interestingly, human breast cancer tissue sections that showed reduced SMAR1 expression exhibited increased surface roughness compared to the adjacent normal breast tissue. Our AFM data establishes that treatment of cells with SMAR1-P44 results into increase in cytoskeletal volume that is supported by comparative gene expression data showing an increase in the expression of specific cytoskeletal proteins compared to the control cells. Altogether, these findings indicate that tumor suppressor function of SMAR1 might be exhibited through smoothening of cell surface by regulating expression of cell surface proteins. Conclusion Tumor suppressor

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  10. Wolbachia surface protein induces innate immune responses in mosquito cells

    Directory of Open Access Journals (Sweden)

    Pinto Sofia B

    2012-01-01

    Full Text Available Abstract Background Wolbachia endosymbiotic bacteria are capable of inducing chronic upregulation of insect immune genes in some situations and this phenotype may influence the transmission of important insect-borne pathogens. However the molecules involved in these interactions have not been characterized. Results Here we show that recombinant Wolbachia Surface Protein (WSP stimulates increased transcription of immune genes in mosquito cells derived from the mosquito Anopheles gambiae, which is naturally uninfected with Wolbachia; at least two of the upregulated genes, TEP1 and APL1, are known to be important in Plasmodium killing in this species. When cells from Aedes albopictus, which is naturally Wolbachia-infected, were challenged with WSP lower levels of upregulation were observed than for the An. gambiae cells. Conclusions We have found that WSP is a strong immune elicitor in a naturally Wolbachia-uninfected mosquito species (Anopheles gambiae while a milder elicitor in a naturally-infected species (Aedes albopictus. Since the WSP of a mosquito non-native (nematode Wolbachia strain was used, these data suggest that there is a generalized tolerance to WSP in Ae. albopictus.

  11. Novel eukaryotic enzymes modifying cell-surface biopolymers

    Directory of Open Access Journals (Sweden)

    Aravind L

    2010-01-01

    Full Text Available Abstract Background Eukaryotic extracellular matrices such as proteoglycans, sclerotinized structures, mucus, external tests, capsules, cell walls and waxes contain highly modified proteins, glycans and other composite biopolymers. Using comparative genomics and sequence profile analysis we identify several novel enzymes that could be potentially involved in the modification of cell-surface glycans or glycoproteins. Results Using sequence analysis and conservation we define the acyltransferase domain prototyped by the fungal Cas1p proteins, identify its active site residues and unify them to the superfamily of classical 10TM acyltransferases (e.g. oatA. We also identify a novel family of esterases (prototyped by the previously uncharacterized N-terminal domain of Cas1p that have a similar fold as the SGNH/GDSL esterases but differ from them in their conservation pattern. Conclusions We posit that the combined action of the acyltransferase and esterase domain plays an important role in controlling the acylation levels of glycans and thereby regulates their physico-chemical properties such as hygroscopicity, resistance to enzymatic hydrolysis and physical strength. We present evidence that the action of these novel enzymes on glycans might play an important role in host-pathogen interaction of plants, fungi and metazoans. We present evidence that in plants (e.g. PMR5 and ESK1 the regulation of carbohydrate acylation by these acylesterases might also play an important role in regulation of transpiration and stress resistance. We also identify a subfamily of these esterases in metazoans (e.g. C7orf58, which are fused to an ATP-grasp amino acid ligase domain that is predicted to catalyze, in certain animals, modification of cell surface polymers by amino acid or peptides. Reviewers This article was reviewed by Gaspar Jekely and Frank Eisenhaber

  12. Novel eukaryotic enzymes modifying cell-surface biopolymers

    Science.gov (United States)

    2010-01-01

    Background Eukaryotic extracellular matrices such as proteoglycans, sclerotinized structures, mucus, external tests, capsules, cell walls and waxes contain highly modified proteins, glycans and other composite biopolymers. Using comparative genomics and sequence profile analysis we identify several novel enzymes that could be potentially involved in the modification of cell-surface glycans or glycoproteins. Results Using sequence analysis and conservation we define the acyltransferase domain prototyped by the fungal Cas1p proteins, identify its active site residues and unify them to the superfamily of classical 10TM acyltransferases (e.g. oatA). We also identify a novel family of esterases (prototyped by the previously uncharacterized N-terminal domain of Cas1p) that have a similar fold as the SGNH/GDSL esterases but differ from them in their conservation pattern. Conclusions We posit that the combined action of the acyltransferase and esterase domain plays an important role in controlling the acylation levels of glycans and thereby regulates their physico-chemical properties such as hygroscopicity, resistance to enzymatic hydrolysis and physical strength. We present evidence that the action of these novel enzymes on glycans might play an important role in host-pathogen interaction of plants, fungi and metazoans. We present evidence that in plants (e.g. PMR5 and ESK1) the regulation of carbohydrate acylation by these acylesterases might also play an important role in regulation of transpiration and stress resistance. We also identify a subfamily of these esterases in metazoans (e.g. C7orf58), which are fused to an ATP-grasp amino acid ligase domain that is predicted to catalyze, in certain animals, modification of cell surface polymers by amino acid or peptides. Reviewers This article was reviewed by Gaspar Jekely and Frank Eisenhaber PMID:20056006

  13. Display of wasp venom allergens on the cell surface of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Borodina, Irina; Jensen, B. M.; Søndergaard, Ib;

    2010-01-01

    Background: Yeast surface display is a technique, where the proteins of interest are expressed as fusions with yeast surface proteins and thus remain attached to the yeast cell wall after expression. Our purpose was to study whether allergens expressed on the cell surface of baker's yeast...... Saccharomyces cerevisiae preserve their native allergenic properties and whether the yeast native surface glycoproteins interfere with IgE binding. We chose to use the major allergens from the common wasp Vespula vulgaris venom: phospholipase A1, hyaluronidase and antigen 5 as the model. Results: The proteins...... their enzymatic activities. Phospholipase A1 severely inhibited the growth of the yeast cells. Antigen 5 - expressing yeast cells bound IgE antibodies from wasp venom allergic patient sera but not from control sera as demonstrated by FACS. Moreover, antigen 5 - expressing yeast cells were capable of mediating...

  14. Surface complexation of neptunium (V) onto whole cells and cell componets of Shewanella alga

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Donald Timothy [Los Alamos National Laboratory; Deo, Randhir P [ASU; Rittmann, Bruce E [ASU; Songkasiri, Warinthorn [UNAFFILIATED

    2008-01-01

    We systematically quantified surface complexation of neptunium(V) onto whole cells of Shewanella alga strain BrY and onto cell wall and extracellular polymeric substances (EPS) of S. alga. We first performed acid and base titrations and used the mathematical model FITEQL with constant-capacitance surface-complexation to determine the concentrations and deprotonation constants of specific surface functional groups. Deprotonation constants most likely corresponded to a carboxyl site associated with amino acids (pK{sub a} {approx} 2.4), a carboxyl group not associated with amino acids (pK{sub a} {approx} 5), a phosphoryl site (pK{sub a} {approx} 7.2), and an amine site (pK{sub a} > 10). We then carried out batch sorption experiments with Np(V) and each of the S. alga components at different pHs. Results show that solution pH influenced the speciation of Np(V) and each of the surface functional groups. We used the speciation sub-model of the biogeochemical model CCBATCH to compute the stability constants for Np(V) complexation to each surface functional group. The stability constants were similar for each functional group on S. alga bacterial whole cells, cell walls, and EPS, and they explain the complicated sorption patterns when they are combined with the aqueous-phase speciation of Np(V). For pH < 8, NpO{sub 2}{sup +} was the dominant form of Np(V), and its log K values for the low-pK{sub a} carboxyl, other carboxyl, and phosphoryl groups were 1.75, 1.75, and 2.5 to 3.1, respectively. For pH greater than 8, the key surface ligand was amine >XNH3+, which complexed with NpO{sub 2}(CO{sub 3}){sub 3}{sup 5-}. The log K for NpO{sub 2}(CO{sub 3}){sub 3}{sup 5-} complexed onto the amine groups was 3.1 to 3.6. All of the log K values are similar to those of Np(V) complexes with aqueous carboxyl and N-containing carboxyl ligands. These results point towards the important role of surface complexation in defining key actinide-microbiological interactions in the subsurface.

  15. A cell cycle and nutritional checkpoint controlling bacterial surface adhesion.

    Directory of Open Access Journals (Sweden)

    Aretha Fiebig

    2014-01-01

    Full Text Available In natural environments, bacteria often adhere to surfaces where they form complex multicellular communities. Surface adherence is determined by the biochemical composition of the cell envelope. We describe a novel regulatory mechanism by which the bacterium, Caulobacter crescentus, integrates cell cycle and nutritional signals to control development of an adhesive envelope structure known as the holdfast. Specifically, we have discovered a 68-residue protein inhibitor of holdfast development (HfiA that directly targets a conserved glycolipid glycosyltransferase required for holdfast production (HfsJ. Multiple cell cycle regulators associate with the hfiA and hfsJ promoters and control their expression, temporally constraining holdfast development to the late stages of G1. HfiA further functions as part of a 'nutritional override' system that decouples holdfast development from the cell cycle in response to nutritional cues. This control mechanism can limit surface adhesion in nutritionally sub-optimal environments without affecting cell cycle progression. We conclude that post-translational regulation of cell envelope enzymes by small proteins like HfiA may provide a general means to modulate the surface properties of bacterial cells.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  18. Heparanase facilitates cell adhesion and spreading by clustering of cell surface heparan sulfate proteoglycans.

    Directory of Open Access Journals (Sweden)

    Flonia Levy-Adam

    Full Text Available Heparanase is a heparan sulfate (HS degrading endoglycosidase participating in extracellular matrix degradation and remodeling. Apart of its well characterized enzymatic activity, heparanase was noted to exert also enzymatic-independent functions. Non-enzymatic activities of heparanase include enhanced adhesion of tumor-derived cells and primary T-cells. Attempting to identify functional domains of heparanase that would serve as targets for drug development, we have identified heparin binding domains of heparanase. A corresponding peptide (residues Lys(158-Asp(171, termed KKDC was demonstrated to physically associate with heparin and HS, and to inhibit heparanase enzymatic activity. We hypothesized that the pro-adhesive properties of heparanase are mediated by its interaction with cell surface HS proteoglycans, and utilized the KKDC peptide to examine this possibility. We provide evidence that the KKDC peptide interacts with cell membrane HS, resulting in clustering of syndecan-1 and syndecan-4. We applied classical analysis of cell morphology, fluorescent and time-lapse microscopy and demonstrated that the KKDC peptide efficiently stimulates the adhesion and spreading of various cell types, mediated by PKC, Src, and the small GTPase Rac1. These results support, and further substantiate the notion that heparanase function is not limited to its enzymatic activity.

  19. Aquatic flower-inspired cell culture platform with simplified medium exchange process for facilitating cell-surface interaction studies.

    Science.gov (United States)

    Hong, Hyeonjun; Park, Sung Jea; Han, Seon Jin; Lim, Jiwon; Kim, Dong Sung

    2016-02-01

    Establishing fundamentals for regulating cell behavior with engineered physical environments, such as topography and stiffness, requires a large number of cell culture experiments. However, cell culture experiments in cell-surface interaction studies are generally labor-intensive and time-consuming due to many experimental tasks, such as multiple fabrication processes in sample preparation and repetitive medium exchange in cell culture. In this work, a novel aquatic flower-inspired cell culture platform (AFIP) is presented. AFIP aims to facilitate the experiments on the cell-surface interaction studies, especially the medium exchange process. AFIP was devised to capture and dispense cell culture medium based on interactions between an elastic polymer substrate and a liquid medium. Thus, the medium exchange can be performed easily and without the need of other instruments, such as a vacuum suction and pipette. An appropriate design window of AFIP, based on scaling analysis, was identified to provide a criterion for achieving stability in medium exchange as well as various surface characteristics of the petal substrates. The developed AFIP, with physically engineered petal substrates, was also verified to exchange medium reliably and repeatedly. A closed structure capturing the medium was sustained stably during cell culture experiments. NIH3T3 proliferation results also demonstrated that AFIP can be applied to the cell-surface interaction studies as an alternative to the conventional method. PMID:26683462

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

    Science.gov (United States)

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

    2007-12-01

    Differences in the distribution of diverse cell surface coat markers were found between Naegleria fowleri and Naegleria lovaniensis. The presence of carbohydrate-containing components in the cell coat of the two species was detected by selective staining with ruthenium red and alcian blue. Using both markers, N. fowleri presented a thicker deposit than N. lovaniensis. The existence of exposed mannose or glucose residues was revealed by discriminatory agglutination with the plant lectin Concanavalin A. These sugar residues were also visualized at the cell surface of these parasites either by transmission electron microscopy or by fluorescein-tagged Concanavalin A. Using this lectin cap formation was induced only in N. fowleri. The anionic sites on the cell surface detected by means of cationized ferritin were more apparent in N. fowleri. Biotinylation assays confirmed that even though the two amoebae species have some analogous plasma membrane proteins, there is a clear difference in their composition.

  1. Cell surface estrogen receptor alpha is upregulated during subchronic metabolic stress and inhibits neuronal cell degeneration.

    Directory of Open Access Journals (Sweden)

    Cristiana Barbati

    Full Text Available In addition to the classical nuclear estrogen receptor, the expression of non-nuclear estrogen receptors localized to the cell surface membrane (mER has recently been demonstrated. Estrogen and its receptors have been implicated in the development or progression of numerous neurodegenerative disorders. Furthermore, the pathogenesis of these diseases has been associated with disturbances of two key cellular programs: apoptosis and autophagy. An excess of apoptosis or a defect in autophagy has been implicated in neurodegeneration. The aim of this study was to clarify the role of ER in determining neuronal cell fate and the possible implication of these receptors in regulating either apoptosis or autophagy. The human neuronal cell line SH-SY5Y and mouse neuronal cells in primary culture were thus exposed to chronic minimal peroxide treatment (CMP, a form of subcytotoxic minimal chronic stress previously that mimics multiple aspects of long-term cell stress and represents a limited molecular proxy for neurodegenerative processes. We actually found that either E2 or E2-bovine serum albumin construct (E2BSA, i.e. a non-permeant form of E2 was capable of modulating intracellular cell signals and regulating cell survival and death. In particular, under CMP, the up-regulation of mERα, but not mERβ, was associated with functional signals (ERK phosphorylation and p38 dephosphorylation compatible with autophagic cytoprotection triggering and leading to cell survival. The mERα trafficking appeared to be independent of the microfilament system cytoskeletal network but was seemingly associated with microtubular apparatus network, i.e., to MAP2 molecular chaperone. Importantly, antioxidant treatments, administration of siRNA to ERα, or the presence of antagonist of ERα hindered these events. These results support that the surface expression of mERα plays a pivotal role in determining cell fate, and that ligand-induced activation of mER signalling exerts a

  2. Cell patterning on polylactic acid through surface-tethered oligonucleotides.

    Science.gov (United States)

    Matsui, Toshiki; Arima, Yusuke; Takemoto, Naohiro; Iwata, Hiroo

    2015-02-01

    Polylactic acid (PLA) is a candidate material to prepare scaffolds for 3-D tissue regeneration. However, cells do not adhere or proliferate well on the surface of PLA because it is hydrophobic. We report a simple and rapid method for inducing cell adhesion to PLA through DNA hybridization. Single-stranded DNA (ssDNA) conjugated to poly(ethylene glycol) (PEG) and to a terminal phospholipid (ssDNA-PEG-lipid) was used for cell surface modification. Through DNA hybridization, modified cells were able to attach to PLA surfaces modified with complementary sequence (ssDNA'). Different cell types can be attached to PLA fibers and films in a spatially controlled manner by using ssDNAs with different sequences. In addition, they proliferate well in a culture medium supplemented with fetal bovine serum. The coexisting modes of cell adhesion through DNA hybridization and natural cytoskeletal adhesion machinery revealed no serious effects on cell growth. The combination of a 3-D scaffold made of PLA and cell immobilization on the PLA scaffold through DNA hybridization will be useful for the preparation of 3-D tissue and organs.

  3. Reversed cell imprinting, AFM imaging and adhesion analyses of cells on patterned surfaces.

    Science.gov (United States)

    Zhou, Xiongtu; Shi, Jian; Zhang, Fan; Hu, Jie; Li, Xin; Wang, Li; Ma, Xueming; Chen, Yong

    2010-05-01

    Cell adhesion and motility depend strongly on the interactions between cells and cell culture substratum. To observe the cell morphology at the interface between cells and artificial substratum or patterned surfaces, we have developed a technique named reversed cell imprinting. After culture and chemical fixation of the cells on a patterned hole array, a liquid polymer was poured on and UV cured, allowing taking off the cell-polymer assembly for a direct observation of the underside cell surface using atomic force microscopy. As expected, we observed local deformation of the cell membrane in the hole area with a penetration depth strongly dependent on the size and depth of the hole as well as the culture time. Quantitative analyses of Hela cells on patterned surfaces of polydimethylsiloxane (PDMS) revealed that the penetration was also position dependent over the cell attachment area due to the non-homogeneous distribution of the membrane stress. With the increase of the culture time, the penetration depth was reduced, in a close correlation with the increase of the cell spreading area. Nevertheless, both cell seeding and adhesion efficiency on high density hole arrays could be significantly increased comparing to that on a smooth surface. Patterned substrates are increasingly required to produce and interrogate new biomaterials for therapeutic benefit. Overall, this work suggests a strategy to endow conventional imaging methods with added functionality to enable easy observation of the underside cell morphology on topographic patterns. PMID:20390138

  4. Polycarbonate surface cell's adhesion examination after Nd:YAG laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ramazani, S.A. Ahmad, E-mail: Ramazani@sharif.ir [Polymer Group, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mousavi, Seyyed Abbas, E-mail: Musavi@che.sharif.ir [Department of Chemistry, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Seyedjafari, Ehsan [Department of Biotechnology, University College of Science, University of Tehran (Iran, Islamic Republic of); Poursalehi, Reza [Department of Physics, University of Shahed, Tehran (Iran, Islamic Republic of); Sareh, Shohreh [Research Center of Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Silakhori, Kaveh [Laser Research Center, Atomic Energy Organization, Tehran (Iran, Islamic Republic of); Poorfatollah, Ali Akbar [Research Center of Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Shamkhali, Amir Nasser [Department of Chemistry, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2009-05-05

    Nd:YAG laser treatment was used in order to increase surface cell adhesion aspects of polycarbonate (PC) films prepared via melt process. The treatment was carried out under different wavelengths and beam diameters. ATR-FTIR and UV spectra obtained from different samples before and after laser treatment in air showed that laser irradiation has induced some chemical and physical changes in surface properties. The irradiated films were also characterized using scanning electron microscopy (SEM) and contact angle measurements. Effect of pulse numbers on the surface properties was also investigated. Cell culture test was used to evaluate cell adhesion property on the PC films before and after treatment. The results obtained from this test showed that after laser treatment, the cells were attached and proliferated extensively on the Nd:YAG laser treated films in comparison with the unmodified PC. Moreover, it was revealed that a decrease in the laser beam diameter and an increase in the irradiated pulse numbers increased surface wettability and caused a better cell attachment on the polymer surface. The obtained results also showed that a decrease in the laser beam diameter and an increase in the irradiated pulse numbers increased surface wettability and caused a better cell attachment on the polymer surface.

  5. EXAFS Study of Uranyl Complexation at Pseudomonas fluorescens Cell Surfaces

    Science.gov (United States)

    Bencheikh, R.; Bargar, J. R.; Tebo, B. M.

    2002-12-01

    Little is known about the roles of microbial biomass as a sink and source for uranium in contaminated aquifers, nor of the impact of bacterial biochemistry on uranium speciation in the subsurface. A significant role is implied by the high affinities of both Gram positive and Gram negative cells for binding uranyl (UO2{ 2+}). In the present study, Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy was used to identify membrane functional groups involved in uranyl binding to the Gram negative bacterium Pseudomonas fluorescens from pH 3 to pH 8. Throughout this pH-range, EXAFS spectra can be described primarily in terms of coordination of carboxylic groups to uranyl. U-C distances characteristic of 4-, 5- and 8- membered rings were observed, as well as the possibility of phosphato groups. Both shell-by-shell fits and principle component analyses indicate that the functional groups involved in binding of uranyl to the cell surface do not vary systematically across the pH range investigated. This result contrasts with EXAFS results of uranyl sorbed to Gram positive bacteria, and suggests an important role for long-chain carboxylate-terminated membrane functional groups in binding uranyl.

  6. Behavior of osteoblastic cells cultured on titanium and structured zirconia surfaces

    Directory of Open Access Journals (Sweden)

    Wiesmann Hans-Peter

    2008-12-01

    Full Text Available Abstract Background Osseointegration is crucial for the long-term success of dental implants and depends on the tissue reaction at the tissue-implant interface. Mechanical properties and biocompatibility make zirconia a suitable material for dental implants, although surface processings are still problematic. The aim of the present study was to compare osteoblast behavior on structured zirconia and titanium surfaces under standardized conditions. Methods The surface characteristics were determined by scanning electron microscopy (SEM. In primary bovine osteoblasts attachment kinetics, proliferation rate and synthesis of bone-associated proteins were tested on different surfaces. Results The results demonstrated that the proliferation rate of cells was significantly higher on zirconia surfaces than on titanium surfaces (p t-test. In contrast, attachment and adhesion strength of the primary cells was significant higher on titanium surfaces (p U test. No significant differences were found in the synthesis of bone-specific proteins. Ultrastructural analysis revealed phenotypic features of osteoblast-like cells on both zirconia and titanium surfaces. Conclusion The study demonstrates distinct effects of the surface composition on osteoblasts in culture. Zirconia improves cell proliferation significantly during the first days of culture, but it does not improve attachment and adhesion strength. Both materials do not differ with respect to protein synthesis or ultrastructural appearance of osteoblasts. Zirconium oxide may therefore be a suitable material for dental implants.

  7. Result of MHI 2-Cell Seamless Dumb-Bell Cavity Vertical Test

    Energy Technology Data Exchange (ETDEWEB)

    Okihira, K. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Hara, H. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Ikeda, N. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Inoue, F. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Sennyu, K. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Geng, Rongli [JLAB; Rimmer, Robert A. [JLAB; Kako, E. [KEK

    2014-12-01

    MHI have supplied several 9-cell cavities for STF (R&D of ILC project at KEK) and have been considering production method for stable quality and cost reduction, seamless dumb-bell cavity was one of them. We had fabricated a 2 cell seamless dumb-bell cavity for cost reduction and measured RF performance in collaboration with JLab, KEK and MHI. Surface treatment recipe for ILC was applied for MHI 2-cell cavity and vertical test was performed at JLab. The cavity reached Eacc=32.4MV/m after BCP and EP. Details of the result are reported.

  8. Surface nanotopography of an anodized Ti–6Al–7Nb alloy enhances cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Her-Hsiung [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung 404, Taiwan (China); Department of Biomedical Informatics, Asia University, Taichung 413, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan (China); Wu, Chia-Ping [Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Sun, Ying-Sui [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Yang, Wei-En [Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Lee, Tzu-Hsin, E-mail: biomaterials@hotmail.com [School of Dentistry, Chung Shan Medical University, Taichung 402, Taiwan (China); Oral Medicine Center, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China)

    2014-12-05

    Highlights: • An electrochemical anodization was applied to α/β-type Ti–6Al–7Nb alloy surface. • Anodized surface had a nontoxic nanoporous topography. • Anodized surface increased proteins adsorption due to nanotopography. • Anodized surface enhanced cell growth due to nanotopography. • Electrochemical anodization has potential as implant surface treatment. - Abstract: The α/β-type Ti–6Al–7Nb alloy is a potential replacement for α/β-type Ti–6Al–4V alloy, which is widely used in biomedical implant applications. The biological response to implant material is dependent on the surface characteristics of the material. In the present study, a simple and fast process was developed to perform an electrochemical anodization treatment on Ti–6Al–7Nb alloy. The proposed process yielded a thin surface nanotopography, which enhanced cell growth on the Ti–6Al–7Nb alloy. The surface characteristics, including the morphology, wettability, and protein adsorption, were investigated, and the cytotoxicity was evaluated according to International Organization for Standardization 10993-5 specifications. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed via fluorescence microscopy and scanning electron microscopy. The anodization process produced a surface nanotopography (pore size <100 nm) on anodized Ti–6Al–7Nb alloy, which enhanced the wettability, protein adsorption, cell adhesion, cell migration, and cell mineralization. The results showed that the surface nanotopography produced using the proposed electrochemical anodization process enhanced cell growth on anodized Ti–6Al–7Nb alloy for implant applications.

  9. Surface nanotopography of an anodized Ti–6Al–7Nb alloy enhances cell growth

    International Nuclear Information System (INIS)

    Highlights: • An electrochemical anodization was applied to α/β-type Ti–6Al–7Nb alloy surface. • Anodized surface had a nontoxic nanoporous topography. • Anodized surface increased proteins adsorption due to nanotopography. • Anodized surface enhanced cell growth due to nanotopography. • Electrochemical anodization has potential as implant surface treatment. - Abstract: The α/β-type Ti–6Al–7Nb alloy is a potential replacement for α/β-type Ti–6Al–4V alloy, which is widely used in biomedical implant applications. The biological response to implant material is dependent on the surface characteristics of the material. In the present study, a simple and fast process was developed to perform an electrochemical anodization treatment on Ti–6Al–7Nb alloy. The proposed process yielded a thin surface nanotopography, which enhanced cell growth on the Ti–6Al–7Nb alloy. The surface characteristics, including the morphology, wettability, and protein adsorption, were investigated, and the cytotoxicity was evaluated according to International Organization for Standardization 10993-5 specifications. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed via fluorescence microscopy and scanning electron microscopy. The anodization process produced a surface nanotopography (pore size <100 nm) on anodized Ti–6Al–7Nb alloy, which enhanced the wettability, protein adsorption, cell adhesion, cell migration, and cell mineralization. The results showed that the surface nanotopography produced using the proposed electrochemical anodization process enhanced cell growth on anodized Ti–6Al–7Nb alloy for implant applications

  10. Investigation of the Cell Surface Proteome of Human Periodontal Ligament Stem Cells.

    Science.gov (United States)

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

    Science.gov (United States)

    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

  12. Characterization of fucosyltransferase activity during mouse spermatogenesis: Evidence for a cell surface fucosyltransferase

    International Nuclear Information System (INIS)

    Fucosyltransferase activity was quantified in mouse germ cells at different stages of spermatogenesis. Specifically, fucosyltransferase activities of pachytene spermatocytes, round spermatids, and cauda epididymal sperm were compared. Fucosyltranferase activity of mixed germ cells displayed an apparent Vmax of 17 pmol (mg of protein)-1 min-1 and an apparent Km of approximately 13 μM for GDP-L-[14C]fucose in the presence of saturating amounts of asialofetuin at 33 degree C. Under these conditions, cellular fucosyltransferase activity was found to increase during spermatogenesis. In agreement with assays of intact cells, examination of subcellular fractions indicated that a large fraction of fucosyltransferase activity was associated with the cell surface. The fraction of fucosyltransferase activity that was associated with the cell surface progressively increased throughout spermatogenesis and epididymal maturation so that nearly all of the fucosyltransferase in epididymal sperm was on the cell surface. Specifically, by comparison of activities in the presence and absence of the detergent NP-40, the fraction of fucosyltransferase activity that was associated with the cell surface in pachytene spermatocytes, round spermatids, and epididymal sperm was 0.36, 0.5, and 0.85, respectively. These results suggest that a cell surface fucosyltransferase may be important during differentiation of spermatogenic cells in the testis as well as during epididymal maturation and fertilization

  13. Defining an optimal surface chemistry for pluripotent stem cell culture in 2D and 3D

    Science.gov (United States)

    Zonca, Michael R., Jr.

    Surface chemistry is critical for growing pluripotent stem cells in an undifferentiated state. There is great potential to engineer the surface chemistry at the nanoscale level to regulate stem cell adhesion. However, the challenge is to identify the optimal surface chemistry of the substrata for ES cell attachment and maintenance. Using a high-throughput polymerization and screening platform, a chemically defined, synthetic polymer grafted coating that supports strong attachment and high expansion capacity of pluripotent stem cells has been discovered using mouse embryonic stem (ES) cells as a model system. This optimal substrate, N-[3-(Dimethylamino)propyl] methacrylamide (DMAPMA) that is grafted on 2D synthetic poly(ether sulfone) (PES) membrane, sustains the self-renewal of ES cells (up to 7 passages). DMAPMA supports cell attachment of ES cells through integrin beta1 in a RGD-independent manner and is similar to another recently reported polymer surface. Next, DMAPMA has been able to be transferred to 3D by grafting to synthetic, polymeric, PES fibrous matrices through both photo-induced and plasma-induced polymerization. These 3D modified fibers exhibited higher cell proliferation and greater expression of pluripotency markers of mouse ES cells than 2D PES membranes. Our results indicated that desirable surfaces in 2D can be scaled to 3D and that both surface chemistry and structural dimension strongly influence the growth and differentiation of pluripotent stem cells. Lastly, the feasibility of incorporating DMAPMA into a widely used natural polymer, alginate, has been tested. Novel adhesive alginate hydrogels have been successfully synthesized by either direct polymerization of DMAPMA and methacrylic acid blended with alginate, or photo-induced DMAPMA polymerization on alginate nanofibrous hydrogels. In particular, DMAPMA-coated alginate hydrogels support strong ES cell attachment, exhibiting a concentration dependency of DMAPMA. This research provides a

  14. Pigment epithelium-derived factor binds to cell-surface F(1)-ATP synthase.

    Science.gov (United States)

    Notari, Luigi; Arakaki, Naokatu; Mueller, David; Meier, Scott; Amaral, Juan; Becerra, S P

    2010-05-01

    Pigment epithelium-derived factor (PEDF), a potent blocker of angiogenesis in vivo, and of endothelial cell migration and tubule formation, binds with high affinity to an as yet unknown protein on the surfaces of endothelial cells. Given that protein fingerprinting suggested a match of a approximately 60 kDa PEDF-binding protein in bovine retina with Bos taurus F(1)-ATP synthase beta-subunit, and that F(1)F(o)-ATP synthase components have been identified recently as cell-surface receptors, we examined the direct binding of PEDF to F(1). Size-exclusion ultrafiltration assays showed that recombinant human PEDF formed a complex with recombinant yeast F(1). Real-time binding as determined by surface plasmon resonance demonstrated that yeast F(1) interacted specifically and reversibly with human PEDF. Kinetic evaluations revealed high binding affinity for PEDF, in agreement with PEDF affinities for endothelial cell surfaces. PEDF blocked interactions between F(1) and angiostatin, another antiangiogenic factor, suggesting overlapping PEDF-binding and angiostatin-binding sites on F(1). Surfaces of endothelial cells exhibited affinity for PEDF-binding proteins of approximately 60 kDa. Antibodies to F(1)beta-subunit specifically captured PEDF-binding components in endothelial plasma membranes. The extracellular ATP synthesis activity of endothelial cells was examined in the presence of PEDF. PEDF significantly reduced the amount of extracellular ATP produced by endothelial cells, in agreement with direct interactions between cell-surface ATP synthase and PEDF. In addition to demonstrating that PEDF binds to cell-surface F(1), these results show that PEDF is a ligand for endothelial cell-surface F(1)F(o)-ATP synthase. They suggest that PEDF-mediated inhibition of ATP synthase may form part of the biochemical mechanisms by which PEDF exerts its antiangiogenic activity. PMID:20412062

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

    OpenAIRE

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

    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. Fra...

  16. Evaluation of PWR and BWR pin cell benchmark results

    International Nuclear Information System (INIS)

    In order to carry out reliable reactor core calculations for a boiled water reactor (BWR) or a pressurized water reactor (PWR) first reactivity calculations have to be carried out for which several calculation programs are available. The purpose of the title project is to exchange experiences to improve the knowledge of this reactivity calculations. In a large number of institutes reactivity calculations of PWR and BWR pin cells were executed by means of available computer codes. Results are compared. It is concluded that the variations in the calculated results are problem dependent. Part of the results is satisfactory. However, further research is necessary

  17. Immunogold labels: cell-surface markers in atomic force microscopy

    OpenAIRE

    Putman, Constant A.J.; Grooth, de, B.G.; Hansma, Paul K.; Hulst, van der, R.W.M.; Greve, Jan

    1993-01-01

    The feasibility of using immunogold labels as cell-surface markers in atomic force microscopy is shown in this paper. The atomic force microscope (AFM) was used to image the surface of immunogold-labeled human lymphocytes. The lymphocytes were isolated from whole blood and labeled by an indirect immunolabeling method using the monoclonal antibody anti-CD3 and a secondary antibody (Goat-anti-Mouse) linked to 30 nm colloidal gold particles. Some of the samples were enhanced by silver deposition...

  18. Cell surface polypeptides of murine T-cell clones expressing cytolytic or amplifier activity.

    OpenAIRE

    Sarmiento, M.; Glasebrook, A L; Fitch, F. W.

    1980-01-01

    Murine cytolytic T-cell and amplifier T-cell clones derived from secondary unidirectional mixed leukocyte cultures were labeled with 125I by the lactoperoxidase method and their polypeptide profiles were analyzed by NaDodSO4/polyacrylamide gel electrophoresis. All cytolytic T-cell clones derived from the same mouse strain yeilded similar cell surface polypeptide profiles. However, profiles obtained with three amplifier T-cell clones were strikingly different from each other as well as from th...

  19. Cell surface proteome of the marine planctomycete Rhodopirellula baltica.

    Science.gov (United States)

    Voigt, Birgit; Hieu, Cao Xuan; Hempel, Kristina; Becher, Dörte; Schlüter, Rabea; Teeling, Hanno; Glöckner, Frank Oliver; Amann, Rudolf; Hecker, Michael; Schweder, Thomas

    2012-06-01

    The surface proteome (surfaceome) of the marine planctomycete Rhodopirellula baltica SH1(T) was studied using a biotinylation and a proteinase K approach combined with SDS-PAGE and mass spectrometry. 52 of the proteins identified in both approaches could be assigned to the group of potential surface proteins. Among them are some high molecular weight proteins, potentially involved in cell-cell attachment, that contain domains shown before to be typical for surface proteins like cadherin/dockerin domains, a bacterial adhesion domain or the fasciclin domain. The identification of proteins with enzymatic functions in the R. baltica surfaceome provides further clues for the suggestion that some degradative enzymes may be anchored onto the cell surface. YTV proteins, which have been earlier supposed to be components of the proteinaceous cell wall of R. baltica, were detected in the surface proteome. Additionally, 8 proteins with a novel protein structure combining a conserved type IV pilin/N-methylation domain and a planctomycete-typical DUF1559 domain were identified. PMID:22623273

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2016-01-01

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

  2. Rho-associated kinase (ROCK) inhibition reverses low cell activity on hydrophobic surfaces

    International Nuclear Information System (INIS)

    Hydrophobic polymers do not offer an adequate scaffold surface for cells to attach, migrate, proliferate, and differentiate. Thus, hydrophobic scaffolds for tissue engineering have traditionally been physicochemically modified to enhance cellular activity. However, modifying the surface by chemical or physical treatment requires supplementary engineering procedures. In the present study, regulation of a cell signal transduction pathway reversed the low cellular activity on a hydrophobic surface without surface modification. Inhibition of Rho-associated kinase (ROCK) by Y-27632 markedly enhanced adhesion, migration, and proliferation of osteoblastic cells cultured on a hydrophobic polystyrene surface. ROCK inhibition regulated cell-cycle-related molecules on the hydrophobic surface. This inhibition also decreased expression of the inhibitors of cyclin-dependent kinases such as p21cip1 and p27kip1 and increased expression of cyclin A and D. These results indicate that defective cellular activity on the hydrophobic surface can be reversed by the control of a cell signal transduction pathway without physicochemical surface modification.

  3. Cell recognition molecule L1 promotes embryonic stem cell differentiation through the regulation of cell surface glycosylation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying [Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044 (China); Department of Clinical Laboratory, Second Affiliated Hospital of Dalian Medical University, Dalian 116023 (China); Huang, Xiaohua [Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044 (China); Department of Clinical Biochemistry, College of Laboratory Medicine, Dalian Medical University, Dalian 116044 (China); An, Yue [Department of Clinical Laboratory, Second Affiliated Hospital of Dalian Medical University, Dalian 116023 (China); Ren, Feng [Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044 (China); Yang, Zara Zhuyun; Zhu, Hongmei; Zhou, Lei [The Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University, Kunming 650228 (China); Department of Anatomy and Developmental Biology, Monash University, Clayton 3800 (Australia); He, Xiaowen; Schachner, Melitta [Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, New Brunswick, NJ (United States); Xiao, Zhicheng, E-mail: zhicheng.xiao@monash.edu [The Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University, Kunming 650228 (China); Department of Anatomy and Developmental Biology, Monash University, Clayton 3800 (Australia); Ma, Keli, E-mail: makeli666@aliyun.com [Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044 (China); Li, Yali, E-mail: yalilipaper@gmail.com [Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044 (China); Department of Anatomy, National University of Singapore, Singapore 119078 (Singapore)

    2013-10-25

    Highlights: •Down-regulating FUT9 and ST3Gal4 expression blocks L1-induced neuronal differentiation of ESCs. •Up-regulating FUT9 and ST3Gal4 expression in L1-ESCs depends on the activation of PLCγ. •L1 promotes ESCs to differentiate into neuron through regulating cell surface glycosylation. -- Abstract: Cell recognition molecule L1 (CD171) plays an important role in neuronal survival, migration, differentiation, neurite outgrowth, myelination, synaptic plasticity and regeneration after injury. Our previous study has demonstrated that overexpressing L1 enhances cell survival and proliferation of mouse embryonic stem cells (ESCs) through promoting the expression of FUT9 and ST3Gal4, which upregulates cell surface sialylation and fucosylation. In the present study, we examined whether sialylation and fucosylation are involved in ESC differentiation through L1 signaling. RNA interference analysis showed that L1 enhanced differentiation of ESCs into neurons through the upregulation of FUT9 and ST3Gal4. Furthermore, blocking the phospholipase Cγ (PLCγ) signaling pathway with either a specific PLCγ inhibitor or knockdown PLCγ reduced the expression levels of both FUT9 and ST3Gal4 mRNAs and inhibited L1-mediated neuronal differentiation. These results demonstrate that L1 promotes neuronal differentiation from ESCs through the L1-mediated enhancement of FUT9 and ST3Gal4 expression.

  4. Cell recognition molecule L1 promotes embryonic stem cell differentiation through the regulation of cell surface glycosylation

    International Nuclear Information System (INIS)

    Highlights: •Down-regulating FUT9 and ST3Gal4 expression blocks L1-induced neuronal differentiation of ESCs. •Up-regulating FUT9 and ST3Gal4 expression in L1-ESCs depends on the activation of PLCγ. •L1 promotes ESCs to differentiate into neuron through regulating cell surface glycosylation. -- Abstract: Cell recognition molecule L1 (CD171) plays an important role in neuronal survival, migration, differentiation, neurite outgrowth, myelination, synaptic plasticity and regeneration after injury. Our previous study has demonstrated that overexpressing L1 enhances cell survival and proliferation of mouse embryonic stem cells (ESCs) through promoting the expression of FUT9 and ST3Gal4, which upregulates cell surface sialylation and fucosylation. In the present study, we examined whether sialylation and fucosylation are involved in ESC differentiation through L1 signaling. RNA interference analysis showed that L1 enhanced differentiation of ESCs into neurons through the upregulation of FUT9 and ST3Gal4. Furthermore, blocking the phospholipase Cγ (PLCγ) signaling pathway with either a specific PLCγ inhibitor or knockdown PLCγ reduced the expression levels of both FUT9 and ST3Gal4 mRNAs and inhibited L1-mediated neuronal differentiation. These results demonstrate that L1 promotes neuronal differentiation from ESCs through the L1-mediated enhancement of FUT9 and ST3Gal4 expression

  5. Tetraploid cells from cytokinesis failure induce aneuploidy and spontaneous transformation of mouse ovarian surface epithelial cells

    OpenAIRE

    Lv, Lei; Zhang, Tianwei; Yi, Qiyi; Huang, Yun; Wang, Zheng; Hou, Heli; Zhang, Huan; Zheng, Wei; Hao, Qiaomei; Guo, Zongyou; Howard J Cooke; Shi, Qinghua

    2012-01-01

    Most ovarian cancers originate from the ovarian surface epithelium and are characterized by aneuploid karyotypes. Aneuploidy, a consequence of chromosome instability, is an early event during the development of ovarian cancers. However, how aneuploid cells are evolved from normal diploid cells in ovarian cancers remains unknown. In the present study, cytogenetic analyses of a mouse syngeneic ovarian cancer model revealed that diploid mouse ovarian surface epithelial cells (MOSECs) experienced...

  6. Monoclonal antibody to human endothelial cell surface internalization and liposome delivery in cell culture.

    Science.gov (United States)

    Trubetskaya, O V; Trubetskoy, V S; Domogatsky, S P; Rudin, A V; Popov, N V; Danilov, S M; Nikolayeva, M N; Klibanov, A L; Torchilin, V P

    1988-02-01

    A monoclonal antibody (mAb), E25, is described that binds to the surface of cultured human endothelial cells. Upon binding E25 is rapidly internalized and digested intracellularly. Selective liposome targeting to the surface of the cells is performed using a biotinylated E25 antibody and an avidin-biotin system. Up to 30% of the cell-adherent liposomal lipid is internalized.

  7. Differential survival of solitary and aggregated bacterial cells promotes aggregate formation on leaf surfaces

    Science.gov (United States)

    Monier, J.-M.; Lindow, S. E.

    2003-01-01

    The survival of individual Pseudomonas syringae cells was determined on bean leaf surfaces maintained under humid conditions or periodically exposed to desiccation stress. Cells of P. syringae strain B728a harboring a GFP marker gene were visualized by epifluorescence microscopy, either directly in situ or after recovery from leaves, and dead cells were identified as those that were stained with propidium iodide in such populations. Under moist, conducive conditions on plants, the proportion of total live cells was always high, irrespective of their aggregated state. In contrast, the proportion of the total cells that remained alive on leaves that were periodically exposed to desiccation stress decreased through time and was only ≈15% after 5 days. However, the fraction of cells in large aggregates that were alive on such plants in both condition was much higher than more solitary cells. Immediately after inoculation, cells were randomly distributed over the leaf surface and no aggregates were observed. However, a very aggregated pattern of colonization was apparent within 7 days, and >90% of the living cells were located in aggregates of 100 cells or more. Our results strongly suggest that, although conducive conditions favor aggregate formation, such cells are much more capable of tolerating environmental stresses, and the preferential survival of cells in aggregates promotes a highly clustered spatial distribution of bacteria on leaf surfaces. PMID:14665692

  8. Interaction of the 2,6-dimethoxysemiquinone and ascorbyl free radicals with Ehrlich ascites cells: a probe of cell-surface charge.

    OpenAIRE

    Pethig, R; Gascoyne, P R; McLaughlin, J. A.; Szent-Györgyi, A

    1984-01-01

    The rate of quenching by Ehrlich ascites cells of anionic 2,6-dimethoxy-p-semiquinone and ascorbyl free radicals is investigated as a function of cell concentration, the blocking of cell-surface sulfhydryl groups by N-ethylmaleimide, and the reduction of cell-surface charge by neuraminidase. The rate of quenching is found to be proportional to cell viability and to the number of free cell-surface sulfhydryl groups. The enzymatic action of neuraminidase results in an increase of the free radic...

  9. Solar flare particle-in-cell simulation results

    International Nuclear Information System (INIS)

    Solar flares are highly energetic phenomena on the Sun, releasing huge amounts of energy, carried amongst others by particles which are accelerated up to a few hundred km/s. In this talk the first results from a flare particle-in-cell (PIC) simulation, conducted to study the particle acceleration mechanism in solar flares, are presented. Two cases are compared: with and without collisions (Coulomb scattering) and likewise for gravity.

  10. Solar flare particle-in-cell simulation results

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Gisela [Niels Bohr Institute, Copenhagen (Denmark); Ruhr-Universitaet Bochum (Germany); Nordlund, Aake; Galsgaard, Klaus; Haugboelle, Troels; Trier Frederiksen, Jacob [Niels Bohr Institute, Copenhagen (Denmark)

    2010-07-01

    Solar flares are highly energetic phenomena on the Sun, releasing huge amounts of energy, carried amongst others by particles which are accelerated up to a few hundred km/s. In this talk the first results from a flare particle-in-cell (PIC) simulation, conducted to study the particle acceleration mechanism in solar flares, are presented. Two cases are compared: with and without collisions (Coulomb scattering) and likewise for gravity.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xujie [State key laboratory of new ceramics and fine processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Feng, Qingling, E-mail: biomater@mail.tsinghua.edu.cn [State key laboratory of new ceramics and fine processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Bachhuka, Akash [Mawson Institute, University of South Australia, Mawson Lakes 5095 (Australia); Vasilev, Krasimir [Mawson Institute, University of South Australia, Mawson Lakes 5095 (Australia); School of Advanced Manufacturing, University of South Australia, Mawson Lakes 5095 (Australia)

    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 (-NH{sub 2}), carboxyl (-COOH) and methyl (-CH{sub 3}), 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 (-COOH and -NH{sub 2}) can absorb more proteins than these modified with more hydrophobic functional group (-CH{sub 3}). 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 -NH{sub 2} modified surfaces encourage osteogenic differentiation; the -COOH modified surfaces promote cell adhesion and spreading and the -CH{sub 3} 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.

  12. One Step Quick Detection of Cancer Cell Surface Marker by Integrated NiFe-based Magnetic Biosensing Cell Cultural Chip

    Institute of Scientific and Technical Information of China (English)

    Chenchen Bao; Lei Chen; Tao Wang; Chong Lei; Furong Tian; Daxiang Cui; Yong Zhou

    2013-01-01

    RGD peptides has been used to detect cell surface integrin and direct clinical effective therapeutic drug selection. Herein we report that a quick one step detection of cell surface marker that was realized by a specially designed NiFe-based magnetic biosensing cell chip combined with functionalized magnetic nanoparti-cles. Magnetic nanoparticles with 20-30 nm in diameter were prepared by coprecipitation and modified with RGD-4C, and the resultant RGD-functionalized magnetic nanoparticles were used for targeting cancer cells cul-tured on the NiFe-based magnetic biosensing chip and distinguish the amount of cell surface receptor-integrin. Cell lines such as Calu3, Hela, A549, CaFbr, HEK293 and HUVEC exhibiting different integrin expression were chosen as test samples. Calu3, Hela, HEK293 and HUVEC cells were successfully identified. This approach has advantages in the qualitative screening test. Compared with traditional method, it is fast, sensitive, low cost, easy-operative, and needs very little human intervention. The novel method has great potential in applications such as fast clinical cell surface marker detection, and diagnosis of early cancer, and can be easily extended to other biomedical applications based on molecular recognition.

  13. Vapour explosions (fuel-coolant interactions) resulting from the sub-surface injection of water into molten metals: preliminary results

    International Nuclear Information System (INIS)

    Preliminary experiments are reported on the relationship between the injection mode of contact and the occurrence and magnitude of vapour explosions. Water was injected beneath the surface of molten metals, chiefly tin at 250 to 9000C. Vapour explosions occurred in many, but not all, cases. The results are compared with Dullforce's observations (Culham Report (CLM-P424) on the dropping mode of contact and it appears that rather different behaviour is found; in particular, the present results suggest that the Temperature Interaction Zone is different for the two modes of contact. (author)

  14. High-risk human papillomavirus E7 expression reduces cell-surface MHC class I molecules and increases susceptibility to natural killer cells

    DEFF Research Database (Denmark)

    Bottley, G; Watherston, O G; Hiew, Y-L;

    2007-01-01

    killer (NK) cells. Tetracycline-regulated induction of HPV16 E7 resulted in reduced expression of cell surface MHC class I molecules and increased NK cell killing. Our results suggest that, for HPV-associated malignancies, reduced MHC class I expression is the result of an active immune evasion strategy...

  15. Analysis of the coagulation of human blood cells on diamond surfaces by atomic force microscopy

    Science.gov (United States)

    Baranauskas, V.; Fontana, M.; Guo, Zhao Jing; Ceragioli, H. J.; Peterlevitz, A. C.

    2004-11-01

    Atomic force microscopy (AFM) was used to study the morphology and coagulation of human blood cells in contact with solid surfaces. Blood was extracted from the veins of healthy adult donors and the samples were used immediately after extraction, deposited either on borosilicate glass or diamond substrates. Some blood samples were anti-coagulated by adding heparin for single cell AFM imaging. No chemicals were used for attaching or immobilizing the cells. The diamond substrates were produced by chemical vapour deposition (CVD diamond) using a hot-filament CVD system fed with ethanol highly diluted in hydrogen. AFM imaging of isolated cells (anti-coagulated by heparin) was only possible on the glass substrates due to the lack of adherence of the cells to the diamond surface. The coagulation results suggest that blood clotting on diamond produces a less rough surface than blood clotting on glass.

  16. Surface modification of microparticles causes differential uptake responses in normal and tumoral human breast epithelial cells

    Science.gov (United States)

    Patiño, Tania; Soriano, Jorge; Barrios, Lleonard; Ibáñez, Elena; Nogués, Carme

    2015-06-01

    The use of micro- and nanodevices as multifunctional systems for biomedical applications has experienced an exponential growth during the past decades. Although a large number of studies have focused on the design and fabrication of new micro- and nanosystems capable of developing multiple functions, a deeper understanding of their interaction with cells is required. In the present study, we evaluated the effect of different microparticle surfaces on their interaction with normal and tumoral human breast epithelial cell lines. For this, AlexaFluor488 IgG functionalized polystyrene microparticles (3 μm) were coated with Polyethyleneimine (PEI) at two different molecular weights, 25 and 750 kDa. The effect of microparticle surface properties on cytotoxicity, cellular uptake and endocytic pathways were assessed for both normal and tumoral cell lines. Results showed a differential response between the two cell lines regarding uptake efficiency and mechanisms of endocytosis, highlighting the potential role of microparticle surface tunning for specific cell targeting.

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

    Science.gov (United States)

    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

  18. Cellular Behavior of Human Adipose-Derived Stem Cells on Wettable Gradient Polyethylene Surfaces

    Directory of Open Access Journals (Sweden)

    Hyun Hee Ahn

    2014-01-01

    Full Text Available Appropriate surface wettability and roughness of biomaterials is an important factor in cell attachment and proliferation. In this study, we investigated the correlation between surface wettability and roughness, and biological response in human adipose-derived stem cells (hADSCs. We prepared wettable and rough gradient polyethylene (PE surfaces by increasing the power of a radio frequency corona discharge apparatus with knife-type electrodes over a moving sample bed. The PE changed gradually from hydrophobic and smooth surfaces to hydrophilic (water contact angle, 90° to ~50° and rough (80 to ~120 nm surfaces as the power increased. We found that hADSCs adhered better to highly hydrophilic and rough surfaces and showed broadly stretched morphology compared with that on hydrophobic and smooth surfaces. The proliferation of hADSCs on hydrophilic and rough surfaces was also higher than that on hydrophobic and smooth surfaces. Furthermore, integrin beta 1 gene expression, an indicator of attachment, and heat shock protein 70 gene expression were high on hydrophobic and smooth surfaces. These results indicate that the cellular behavior of hADSCs on gradient surface depends on surface properties, wettability and roughness.

  19. The role of a cell surface inhibitor in early signal transduction associated with the regulation of cell division and differentiation

    Science.gov (United States)

    Johnson, T. C.; Enebo, D. J.; Moos, P. J.; Fattaey, H. K.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    Serum stimulation of quiescent human fibroblast cultures resulted in a hyperphosphorylation of the nuclear retinoblastoma gene susceptibility product (RB). However, serum stimulation in the presence of 9 x 10(-8) M of a purified bovine sialoglycopeptide (SGP) cell surface inhibitor abrogated the hyperphosphorylation of the RB protein and the subsequent progression of cells through the mitotic cycle. The experimental results suggest that the SGP mediated its cell cycle arrest at a site in the cell cycle that was at the time of RB phosphorylation or somewhat upstream of the modification of this regulatory protein of cell division. Both cells serum-deprived and serum stimulated in the presence of the SGP displayed only a hypophosphorylated RB protein, consistent with the SGP-mediated cell cycle arrest point being near the G1/S interface.

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

    Science.gov (United States)

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

    2016-01-11

    Epithelial sheets are crucial components of all metazoan animals, enclosing organs and protecting the animal from its environment. Epithelial homeostasis poses unique challenges, as addition of new cells and loss of old cells must be achieved without disrupting the fluid-tight barrier and apicobasal polarity of the epithelium. Several studies have identified cell biological mechanisms underlying extrusion of cells from epithelia, but far less is known of the converse mechanism by which new cells are added. Here, we combine molecular, pharmacological, and laser-dissection experiments with theoretical modeling to characterize forces driving emergence of an apical surface as single nascent cells are added to a vertebrate epithelium in vivo. We find that this process involves the interplay between cell-autonomous actin-generated pushing forces in the emerging cell and mechanical properties of neighboring cells. Our findings define the forces driving this cell behavior, contributing to a more comprehensive understanding of epithelial homeostasis. PMID:26766441

  1. Engineering micropatterned surfaces to modulate the function of vascular stem cells

    International Nuclear Information System (INIS)

    Highlights: • We examine vascular stem cell function on microgrooved and micropost patterned polymer substrates. • 10 μm microgrooved surfaces significantly lower VSC proliferation but do not modulate calcified matrix deposition. • Micropost surfaces significantly lower VSC proliferation and decrease calcified matrix deposition. - Abstract: Multipotent vascular stem cells have been implicated in vascular disease and in tissue remodeling post therapeutic intervention. Hyper-proliferation and calcified extracellular matrix deposition of VSC cause blood vessel narrowing and plaque hardening thereby increasing the risk of myocardial infarct. In this study, to optimize the surface design of vascular implants, we determined whether micropatterned polymer surfaces can modulate VSC differentiation and calcified matrix deposition. Undifferentiated rat VSC were cultured on microgrooved surfaces of varied groove widths, and on micropost surfaces. 10 μm microgrooved surfaces elongated VSC and decreased cell proliferation. However, microgrooved surfaces did not attenuate calcified extracellular matrix deposition by VSC cultured in osteogenic media conditions. In contrast, VSC cultured on micropost surfaces assumed a dendritic morphology, were significantly less proliferative, and deposited minimal calcified extracellular matrix. These results have significant implications for optimizing the design of cardiovascular implant surfaces

  2. Bacterial Cell Surface Damage Due to Centrifugal Compaction

    NARCIS (Netherlands)

    Peterson, Brandon W.; Sharma, Prashant K.; van der Mei, Henny C.; Busscher, Henk J.

    2012-01-01

    Centrifugal damage has been known to alter bacterial cell surface properties and interior structures, including DNA. Very few studies exist on bacterial damage caused by centrifugation because of the difficulty in relating centrifugation speed and container geometry to the damage caused. Here, we pr

  3. Oligonucleotide delivery with cell surface binding and cell penetrating Peptide amphiphile nanospheres.

    Science.gov (United States)

    Mumcuoglu, Didem; Sardan, Melis; Tekinay, Turgay; Guler, Mustafa O; Tekinay, Ayse B

    2015-05-01

    A drug delivery system designed specifically for oligonucleotide therapeutics can ameliorate the problems associated with the in vivo delivery of these molecules. The internalization of free oligonucleotides is challenging, and cytotoxicity is the main obstacle for current transfection vehicles. To develop nontoxic delivery vehicles for efficient transfection of oligonucleotides, we designed a self-assembling peptide amphiphile (PA) nanosphere delivery system decorated with cell penetrating peptides (CPPs) containing multiple arginine residues (R4 and R8), and a cell surface binding peptide (KRSR), and report the efficiency of this system in delivering G-3129, a Bcl-2 antisense oligonucleotide (AON). PA/AON (peptide amphiphile/antisense oligonucleotide) complexes were characterized with regards to their size and secondary structure, and their cellular internalization efficiencies were evaluated. The effect of the number of arginine residues on the cellular internalization was investigated by both flow cytometry and confocal imaging, and the results revealed that uptake efficiency improved as the number of arginines in the sequence increased. The combined effect of cell penetration and surface binding property on the cellular internalization and its uptake mechanism was also evaluated by mixing R8-PA and KRSR-PA. R8 and R8/KRSR decorated PAs were found to drastically increase the internalization of AONs compared to nonbioactive PA control. Overall, the KRSR-decorated self-assembled PA nanospheres were demonstrated to be noncytotoxic delivery vectors with high transfection rates and may serve as a promising delivery system for AONs. PMID:25828697

  4. Preliminary results of direct cell-matrix assembly technology

    Institute of Scientific and Technical Information of China (English)

    LIU Haixia; YAN Yongnian; XIONG Zhuo; CHENG Jie; WANG Xiaohong; LIN Feng; WANG Changyong

    2005-01-01

    @@ Tissue loss and end-stage organ failure has been an emergent problem for humanity[1]. Solving this problem at the most basic level is currently an area of great interest to many researchers. At the end of the 20th century, tissue engineering technology began using formed scaffolds to indirectly control the assembly of cells. This technology has resulted in a new way to artificially fabricate tissues. But the method has been limited to simple tissue types, such as bone, skin, muscle and tendon[2―5]. The fabrication of complex organs by this technology is still not possible. A possible alternative is assembling cells directly into a viable and predefined structure[6―9].

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

    Science.gov (United States)

    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.

  6. Sugar-fiber Imprinting to Generate Microgrooves on Polymeric Film Surfaces for Contact Guidance of Cells

    Institute of Scientific and Technical Information of China (English)

    屈泽华; 丁建东

    2012-01-01

    Anisotropic surface topography is known to induce the contact guidance of cells, and facile and biocompatible approaches of the physical modification of the pertinent matrix surfaces are thus meaningful for biomaterials. Herein, we put forward a sugar-fiber imprinting technique to generate microgrooves on hydrophobic polymers demonstrated by the poly(lactic-eo-glycolic acid) (PLGA) films. Microgrooves were conveniently generated after removing sugar fibers simply by water. The resulting locally anisotropic microgrooves were confirmed to elongate the cells cultured on the surface.

  7. Oxidation state of chromium associated with cell surfaces of Shewanella oneidensis during chromate reduction

    Energy Technology Data Exchange (ETDEWEB)

    Neal, Andrew L.; Lowe, Kristine; Daulton, Tyrone L.; Jones-Meehan, Joanne; Little, Brenda J

    2002-12-30

    Employing electron energy loss spectroscopy (EELS) and X-ray photoelectron spectroscopy (XPS), we demonstrate that in both aerobic and anaerobic culture Shewanella oneidensis cells are capable of chromate reduction. No Cr(VI) or Cr(V) species were identified at the cell surfaces in Cr 2p{sub 3/}ore photoelectron spectra. More chromium was associated with cell surfaces recovered from anaerobic medium than aerobic. Multiplet-splitting models derived for Cr(III) and Cr(IV) were employed to determine contributions from each ion to Cr 2p{sub 3/2} photopeaks collected from the various cell treatments. Whilst in all cases Cr(III) was the major ion associated with cell surfaces, a significant contribution was identified due to Cr(IV) in anaerobically grown cells. The Cr(IV) contribution was far less when cells were grown aerobically. Moreover, when anaerobically grown cells were exposed to oxygen very little re-oxidation of Cr-precipitates occurred, the precipitates were again identified as a mixture of Cr(III) and Cr(IV). A positive relationship was observed between amounts of chromium and phosphorous associated with cell surfaces resulting from the various treatments, suggesting the precipitates included Cr(III)-phosphate. The fact that Cr(IV) remained associated with precipitates following re-oxidation suggests that under anaerobic conditions the intermediate ion is afforded sufficient stability to be incorporated within the precipitate matrix and thus conferred a degree of protection from oxidation.

  8. Cell surface hydrophobicity is conveyed by S-layer proteins - A study in recombinant lactobacilli

    NARCIS (Netherlands)

    Mei, H.C. van der; Belt-Gritter, B. van de; Pouwels, P.H.; Martinez, B.; Busscher, H.J.

    2003-01-01

    Cell surface hydrophobicity is one of the most important factors controlling adhesion of microorganisms to surfaces. In this paper, cell surface properties of lactobacilli and recombinant lactobacilli with and without a surface layer protein (SLP) associated with cell surface hydrophobicity were det

  9. Methods To Identify Aptamers against Cell Surface Biomarkers

    Directory of Open Access Journals (Sweden)

    Frédéric Ducongé

    2011-09-01

    Full Text Available 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.

  10. Alterations in cell surface area and deformability of individual human red blood cells in stored blood

    CERN Document Server

    Park, HyunJoo; Lee, SangYun; Kim, Kyoohyun; Sohn, Yong-Hak; Jang, Seongsoo; Park, YongKeun

    2015-01-01

    The functionality and viability of stored human red blood cells (RBCs) is an important clinical issue in transfusion. To systematically investigate changes in stored whole blood, the hematological properties of individual RBCs were quantified in blood samples stored for various periods with and without a preservation solution called CPDA-1. With 3-D quantitative phase imaging techniques, the optical measurements of the 3-D refractive index (RI) distributions and membrane fluctuations were done at the individual cell level. From the optical measurements, the morphological (volume, surface area and sphericity), biochemical (hemoglobin content and concentration), and mechanical parameters (dynamic membrane fluctuation) were simultaneously quantified to investigate the functionalities and their progressive alterations in stored RBCs. Our results show that the stored RBCs without CPDA-1 had a dramatic morphological transformation from discocytes to spherocytes within 2 weeks which was accompanied with significant ...

  11. Cell-to-cell heterogeneity in cortical tension specifies curvature of contact surfaces in Caenorhabditis elegans embryos.

    Directory of Open Access Journals (Sweden)

    Masashi Fujita

    Full Text Available In the two-cell stage embryos of Caenorhabditis elegans, the contact surface of the two blastomeres forms a curve that bulges from the AB blastomere to the P₁ blastomere. This curve is a consequence of the high intracellular hydrostatic pressure of AB compared with that of P₁. However, the higher pressure in AB is intriguing because AB has a larger volume than P₁. In soap bubbles, which are a widely used model of cell shape, a larger bubble has lower pressure than a smaller bubble. Here, we reveal that the higher pressure in AB is mediated by its higher cortical tension. The cell fusion experiments confirmed that the curvature of the contact surface is related to the pressure difference between the cells. Chemical and genetic interferences showed that the pressure difference is mediated by actomyosin. Fluorescence imaging indicated that non-muscle myosin is enriched in the AB cortex. The cell killing experiments provided evidence that AB but not P₁ is responsible for the pressure difference. Computer simulation clarified that the cell-to-cell heterogeneity of cortical tensions is indispensable for explaining the pressure difference. This study demonstrates that heterogeneity in surface tension results in significant deviations of cell behavior compared to simple soap bubble models, and thus must be taken into consideration in understanding cell shape within embryos.

  12. Cell-to-cell heterogeneity in cortical tension specifies curvature of contact surfaces in Caenorhabditis elegans embryos.

    Science.gov (United States)

    Fujita, Masashi; Onami, Shuichi

    2012-01-01

    In the two-cell stage embryos of Caenorhabditis elegans, the contact surface of the two blastomeres forms a curve that bulges from the AB blastomere to the P₁ blastomere. This curve is a consequence of the high intracellular hydrostatic pressure of AB compared with that of P₁. However, the higher pressure in AB is intriguing because AB has a larger volume than P₁. In soap bubbles, which are a widely used model of cell shape, a larger bubble has lower pressure than a smaller bubble. Here, we reveal that the higher pressure in AB is mediated by its higher cortical tension. The cell fusion experiments confirmed that the curvature of the contact surface is related to the pressure difference between the cells. Chemical and genetic interferences showed that the pressure difference is mediated by actomyosin. Fluorescence imaging indicated that non-muscle myosin is enriched in the AB cortex. The cell killing experiments provided evidence that AB but not P₁ is responsible for the pressure difference. Computer simulation clarified that the cell-to-cell heterogeneity of cortical tensions is indispensable for explaining the pressure difference. This study demonstrates that heterogeneity in surface tension results in significant deviations of cell behavior compared to simple soap bubble models, and thus must be taken into consideration in understanding cell shape within embryos. PMID:22253922

  13. "Race for the Surface": Eukaryotic Cells Can Win.

    Science.gov (United States)

    Pham, Vy T H; Truong, Vi Khanh; Orlowska, Anna; Ghanaati, Shahram; Barbeck, Mike; Booms, Patrick; Fulcher, Alex J; Bhadra, Chris M; Buividas, Ričardas; Baulin, Vladimir; Kirkpatrick, C James; Doran, Pauline; Mainwaring, David E; Juodkazis, Saulius; Crawford, Russell J; Ivanova, Elena P

    2016-08-31

    With an aging population and the consequent increasing use of medical implants, managing the possible infections arising from implant surgery remains a global challenge. Here, we demonstrate for the first time that a precise nanotopology provides an effective intervention in bacterial cocolonization enabling the proliferation of eukaryotic cells on a substratum surface, preinfected by both live Gram-negative, Pseudomonas aeruginosa, and Gram-positive, Staphylococcus aureus, pathogenic bacteria. The topology of the model black silicon (bSi) substratum not only favors the proliferation of eukaryotic cells but is biocompatible, not triggering an inflammatory response in the host. The attachment behavior and development of filopodia when COS-7 fibroblast cells are placed in contact with the bSi surface are demonstrated in the dynamic study, which is based on the use of real-time sequential confocal imaging. Bactericidal nanotopology may enhance the prospect for further development of inherently responsive antibacterial nanomaterials for bionic applications such as prosthetics and implants.

  14. Cell adhesion on Ti surface with controlled roughness

    Energy Technology Data Exchange (ETDEWEB)

    Burgos-Asperilla, L.; Garcia-Alonso, M. C.; Escudero, M. L.; Alonso, C.

    2015-07-01

    In this report, the in situ interaction between Saos-2 osteoblast cells and a smooth Ti surface was examined over time. The adhesion kinetics and mechanisms of cellular proliferation were monitored by quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). The rate of Saos-2 attachment on Ti surfaces, obtained from the measurements performed with the QCM, is a first-order reaction, with k=2.10{sup -}3 min{sup -}1. The impedance measurements indicate that in the absence of cells, the Ti resistance diminishes over time (7 days), due to the presence of amino acids and proteins from the culture medium that have been adsorbed, while in the presence of osteoblasts, this decrease is much greater because of the compounds generated by the cells that accelerate the dissolution of Ti. (Author)

  15. Galectin-1-mediated cell adhesion, invasion and cell death in human anaplastic large cell lymphoma: Regulatory roles of cell surface glycans

    OpenAIRE

    Suzuki, Osamu; Abe, Masafumi

    2014-01-01

    Galectin-1 is known to be one of the extracellular matrix proteins. To elucidate the biological roles of galectin-1 in cell adhesion and invasion of human anaplastic large cell lymphoma, we performed cell adhesion and invasion assays using the anaplastic large cell lymphoma cell line H-ALCL, which was previously established in our laboratory. From the cell surface lectin array, treatment with neuraminidase from Arthrobacter ureafaciens which cleaves all linkage types of cell surface sialic ac...

  16. Surface modification of hydrophobic polymers for improvement of endothelial cell-surface interactions

    NARCIS (Netherlands)

    Dekker, A.; Reitsma, K.; Beugeling, T.; Bantjes, A.; Feijen, J.; Kirkpatrick, C.J.; Aken, van W.G.

    1992-01-01

    The aim of this study is to improve the interaction of endothelial cells with polymers used in vascular prostheses. Polytetrafluoroethylene (PTFE; Teflon) films were treated by means of nitrogen and oxygen plasmas. Depending on the plasma exposure time, modified PTFE surfaces showed water-contact an

  17. Live cell imaging based on surface plasmon-enhanced fluorescence microscopy using random nanostructures

    Science.gov (United States)

    Oh, Youngjin; Lee, Wonju; Son, Taehwang; Kim, Sook Young; Shin, Jeon-Soo; Kim, Donghyun

    2014-02-01

    Localized surface plasmon enhanced microscopy based on nanoislands of random spatial distribution was demonstrated for imaging live cells and molecular interactions. Nanoislands were produced without lithography by high temperature annealing under various processing conditions. The localization of near-field distribution that is associated with localized surface plasmon on metallic random nanoislands was analyzed theoretically and experimentally in comparison with periodic nanostructures. For experimental validation in live cell imaging, mouse macrophage-like cell line stained with Alexa Fluor 488 was prepared on nanoislands. The results suggest the possibility of attaining the imaging resolution on the order of 80 nm.

  18. Resonance surface enhanced Raman optical activity of myoglobin as a result of optimized resonance surface enhanced Raman scattering conditions

    DEFF Research Database (Denmark)

    Abdali, Salim; Johannessen, Christian; Nygaard, Jesper;

    2007-01-01

    Using Surface enhanced ROA (SEROA), novel results are achieved by combining Raman Optical Activity (ROA) and resonance Surface Enhanced Raman Scattering (SERRS), applied on myoglobin. The novelty of this work is ascribed the first time reporting on chiral results of a study performed on a protein...... has shown that the SERS effect behaves consequently, depending on the concentration ratio of each component, i.e., myoglobin, Ag colloids and NaCl. Accordingly, it is shown here that SERS intensity has its maximum at certain concentration of these components, whereas below or above this value......, the intensity decreases. The optimization results can be considered as a completion of the hitherto known phenomenon "dilution effect", which takes only account for higher concentrations. Furthermore, the optimization of the parameters seems to be necessary for a successful SEROA measurement, which enables...

  19. Role of the retinoblastoma protein in cell cycle arrest mediated by a novel cell surface proliferation inhibitor

    Science.gov (United States)

    Enebo, D. J.; Fattaey, H. K.; Moos, P. J.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    A novel cell regulatory sialoglycopeptide (CeReS-18), purified from the cell surface of bovine cerebral cortex cells has been shown to be a potent and reversible inhibitor of proliferation of a wide array of fibroblasts as well as epithelial-like cells and nontransformed and transformed cells. To investigate the possible mechanisms by which CeReS-18 exerts its inhibitory action, the effect of the inhibitor on the posttranslational regulation of the retinoblastoma susceptibility gene product (RB), a tumor suppressor gene, has been examined. It is shown that CeReS-18 mediated cell cycle arrest of both human diploid fibroblasts (HSBP) and mouse fibroblasts (Swiss 3T3) results in the maintenance of the RB protein in the hypophosphorylated state, consistent with a late G1 arrest site. Although their normal nontransformed counterparts are sensitive to cell cycle arrest mediated by CeReS-18, cell lines lacking a functional RB protein, through either genetic mutation or DNA tumor virus oncoprotein interaction, are less sensitive. The refractory nature of these cells is shown to be independent of specific surface receptors for the inhibitor, and another tumor suppressor gene (p53) does not appear to be involved in the CeReS-18 inhibition of cell proliferation. The requirement for a functional RB protein product, in order for CeReS-18 to mediate cell cycle arrest, is discussed in light of regulatory events associated with density-dependent growth inhibition.

  20. Folic acid functionalized surface highlights 5-methylcytosine-genomic content within circulating tumor cells

    KAUST Repository

    Malara, Natalia

    2014-07-01

    Although the detection of methylated cell free DNA represents one of the most promising approaches for relapse risk assessment in cancer patients, the low concentration of cell-free circulating DNA constitutes the biggest obstacle in the development of DNA methylation-based biomarkers from blood. This paper describes a method for the measurement of genomic methylation content directly on circulating tumor cells (CTC), which could be used to deceive the aforementioned problem. Since CTC are disease related blood-based biomarkers, they result essential to monitor tumor\\'s stadiation, therapy, and early relapsing lesions. Within surface\\'s bio-functionalization and cell\\'s isolation procedure standardization, the presented approach reveals a singular ability to detect high 5-methylcytosine CTC-subset content in the whole CTC compound, by choosing folic acid (FA) as transducer molecule. Sensitivity and specificity, calculated for FA functionalized surface (FA-surface), result respectively on about 83% and 60%. FA-surface, allowing the detection and characterization of early metastatic dissemination, provides a unique advance in the comprehension of tumors progression and dissemination confirming the presence of CTC and its association with high risk of relapse. This functionalized surface identifying and quantifying high 5-methylcytosine CTC-subset content into the patient\\'s blood lead significant progress in cancer risk assessment, also providing a novel therapeutic strategy.© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. RESULTS OF HEMATOPOIETIC CELL TRANSPLANTATION IN PEDIATRIC LEUKEMIA

    Directory of Open Access Journals (Sweden)

    A. Mousavi

    2008-05-01

    Full Text Available Hematopoietic cell transplantation (HCT is an accepted treatment for acute myeloid leukemia (AML in first remission, the treatment of choice for chronic myeloid leukemia (CML and high risk groups of ALL who relapse with conventional chemotherapy. We assessed results of HCT for pediatric leukemia in our center. A total of 92 children, 63 with diagnose of AML, 23 with ALL and 6 with CML received allogeneic transplantation from HLA full matched siblings (57.6% and autologous transplantation (42.4%. Source of hematopoietic cells were peripheral blood 83.7%, bone marrow 15.2% and cord blood 1.6%. The median transplanted nucleated cells were 6.4 ± 4.7 ×108 /Kg (body weight of patients and mononuclear cells were 5.5 ± 2.9×108/Kg. The most common conditioning regimens were cyclophosphamide + busulfan. Prophylaxis regimen for GVHD was cyclosporin ± methotrexate. GVHD occurred in 50 (54.3% patients. Eighty five of children had engraftment, 26 (28.6% relapsed and 57 (62% are alive. The most common cause of death was relapse (68.6%. Five years overall survival of patients with AML and ALL were 49% and 44% respectively and disease free survival of them were 52% and 49%. One year overall survival and disease free survival of CML was 57%. Overall survival increased with increasing age of patients at transplantation time (P = 0.06. Longer survival significantly related to earlier WBC and platelet recovery (P < 0.0001 and P = 0.006 respectively. Considering acceptable overall and disease free survival of patients after HCT, we concluded that is a good modality in treatment of leukemia of children.

  2. Cell-surface expression of Hsp70 on hematopoietic cancer cells after inhibition of HDAC activity

    DEFF Research Database (Denmark)

    Jensen, Helle; Andresen, Lars; Hansen, Karen Aagaard;

    2009-01-01

    We show that inhibition of HDAC activity leads to surface expression of Hsp70 on various hematopoietic cancer cells, an occurance that was not observed on naïve or activated peripheral blood cells. HDAC inhibitor-mediated Hsp70 surface expression was confined to the apoptotic Annexin V-positive c......We show that inhibition of HDAC activity leads to surface expression of Hsp70 on various hematopoietic cancer cells, an occurance that was not observed on naïve or activated peripheral blood cells. HDAC inhibitor-mediated Hsp70 surface expression was confined to the apoptotic Annexin V......-positive cells and blocked by inhibition of apoptosis. Other chemotherapeutic inducers of apoptosis such as etoposide and camptothecin also led to a robust induction of Hsp70 surface expression. Hsp70 expression was, however, not caused by induction of apoptosis per se, as activated CD4 T cells remained Hsp70...... surface-negative despite effective induction of apoptosis. Interestingly, inhibition of endolysosomes or normal ER/Golgi transport did not affect Hsp70 surface expression. Intracellular calcium and the transcription factor Sp1, which has been shown previously to be important for the intracellular stress...

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

    Science.gov (United States)

    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.

  4. MEMS-based dynamic cell-to-cell culture platforms using electrochemical surface modifications

    International Nuclear Information System (INIS)

    MEMS-based biological platforms with the capability of both spatial placements and time releases of living cells for cell-to-cell culture experiments have been designed and demonstrated utilizing electrochemical surface modification effects. The spatial placement is accomplished by electrochemical surface modification of substrate surfaces to be either adhesive or non-adhesive for living cells. The time control is achieved by the electrical activation of the selective indium tin oxide co-culture electrode to allow the migration of living cells onto the electrode to start the cell-to-cell culture studies. Prototype devices have a three-electrode design with an electrode size of 50 × 50 µm2 and the separation gaps of 2 µm between them. An electrical voltage of −1.5 V has been used to activate the electrodes independently and sequentially to demonstrate the dynamic cell-to-cell culture experiments of NIH 3T3 fibroblast and Madin Darby canine kidney cells. As such, this MEMS platform could be a basic yet versatile tool to characterize transient cell-to-cell interactions

  5. Selective labelling of cell-surface proteins using CyDye DIGE Fluor minimal dyes.

    Science.gov (United States)

    Hagner-McWhirter, Asa; Winkvist, Maria; Bourin, Stephanie; Marouga, Rita

    2008-01-01

    Surface proteins are central to the cell's ability to react to its environment and to interact with neighboring cells. They are known to be inducers of almost all intracellular signaling. Moreover, they play an important role in environmental adaptation and drug treatment, and are often involved in disease pathogenesis and pathology (1). Protein-protein interactions are intrinsic to signaling pathways, and to gain more insight in these complex biological processes, sensitive and reliable methods are needed for studying cell surface proteins. Two-dimensional (2-D) electrophoresis is used extensively for detection of biomarkers and other targets in complex protein samples to study differential changes. Cell surface proteins, partly due to their low abundance (1 2% of cellular proteins), are difficult to detect in a 2-D gel without fractionation or some other type of enrichment. They are also often poorly represented in 2-D gels due to their hydrophobic nature and high molecular weight (2). In this study, we present a new protocol for intact cells using CyDye DIGE Fluor minimal dyes for specific labeling and detection of this important group of proteins. The results showed specific labeling of a large number of cell surface proteins with minimal labeling of intracellular proteins. This protocol is rapid, simple to use, and all three CyDye DIGE Fluor minimal dyes (Cy 2, Cy 3 and Cy 5) can be used to label cell-surface proteins. These features allow for multiplexing using the 2-D Fluorescence Difference Gel Electrophoresis (2-D DIGE) with Ettan DIGE technology and analysis of protein expression changes using DeCyder 2-D Differential Analysis Software. The level of cell-surface proteins was followed during serum starvation of CHO cells for various lengths of time (see Table 1). Small changes in abundance were detected with high accuracy, and results are supported by defined statistical methods.

  6. Surface code—biophysical signals for apoptotic cell clearance

    Science.gov (United States)

    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.

  7. Surface code—biophysical signals for apoptotic cell clearance

    International Nuclear Information System (INIS)

    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. (paper)

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

    Science.gov (United States)

    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

  9. Involvement of cell surface phosphatidylinositol-anchored glycoproteins in cell-cell adhesion of chick embryo myoblasts

    OpenAIRE

    1989-01-01

    During myogenesis myoblasts fuse to form multinucleate cells that express muscle-specific proteins. A specific cell-cell adhesion process precedes lipid bilayer union during myoblast fusion (Knudsen, K. A., and A. F. Horwitz. 1977. Dev. Biol. 58:328-338) and is mediated by cell surface glycoproteins (Knudsen, K. A., 1985. J. Cell Biol. 101:891- 897). In this paper we show that myoblast adhesion and myotube formation are inhibited by treating fusion-competent myoblasts with phosphatidylinosito...

  10. Surface modified alginate microcapsules for 3D cell culture

    Science.gov (United States)

    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.

  11. Establishment of cell surface engineering and its development.

    Science.gov (United States)

    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

  12. Anomalous cell surface structure of sickle cell anemia erythrocytes as demonstrated by cell surface labeling and endo-beta-galactosidase treatment

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Overexpression of Cell Surface Cytokeratin 8 in Multidrug-Resistant MCF-7/MX Cells Enhances Cell Adhesion to the Extracellular Matrix

    Directory of Open Access Journals (Sweden)

    Fang Liu

    2008-11-01

    Full Text Available Accumulating evidence suggests that multiple complex mechanisms may be involved, simultaneously or complementarily, in the emergence and development of multidrug resistance (MDR in various cancers. Cell adhesion-mediated MDR is one such mechanism. In the present study, we initially observed increased cell adhesion to extracellular matrix proteins by the MDR human breast tumor cell line MCF-7/MX compared to its parental cells. We then used a strategy that combined antibody-based screening technique and mass spectrometry-based proteomics to identify membrane proteins that contribute to the enhanced adhesion of MCF-7/MX cells. Using MCF-7/MX cells as immunogen, we isolated a mouse monoclonal antibody, 9C6, that preferentially reacts with MCF-7/MX cells over the parental MCF-7 cells. The molecular target of 9C6 was identified as cytokeratin 8 (CK8, which was found to be overexpressed on the cell surface of MCF-7/MX cells. We further observed that down-regulation of cell surface levels of CK8 through siRNA transfection significantly inhibited MCF-7/MX cell adhesion to fibronectin and vitronectin. In addition, anti-CK8 siRNA partially reversed the MDR phenotype of MCF-7/MX cells. Taken together, our results suggest that alterations in the expression level and cellular localization of CK8 may play a significant role in enhancing the cellular adhesion of MDR MCF-7/MX cells.

  14. Stable isotope labeling of oligosaccharide cell surface antigens

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Silks, L.A. III; Martinez, R.A. [and others

    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.

  15. Expression of cancer stem cell surface markers after chemotherapeutic drug treatment to reflect breast cancer cell regrowth

    Institute of Scientific and Technical Information of China (English)

    Qing Liu; Wings Tjing Yung Loo; Louis Wing Cheong Chow; Kelly Wei Yu Rui

    2014-01-01

    Objective To detect the cell viability and the expressions of stem cell surface markers after chemotherapeutic drug treatment. Methods We observed the cytotoxic effects of three chemotherapeutic agents [ epirubicin ( Epi ) , fluorouracil ( 5-FU ) and cyclophosphamide ( Cyc ) ] in three cell lines, and the cell viabilities after removed these chemotherapeutic agents. Expressions of stem cell surface markers CD44, CD24, CD90, CD14 and aldehyde dehydrogenase1(ALDH1) in breast cancer cells were analyzed by real-time PCR. The post hoc analysis (Tukey’s tests) in conjunction with one-way ANOVA was used for statistical analysis. Results The initial cytotoxic efficacy was most notable. After the treatment of the same therapeutic agents, cell viability was decreased by 64. 8% 35. 14%, 32. 25% in BT-483 cells, 66. 4%, 22. 94% and 45. 88% in MDA-MB-231 cells, 97. 1%, 99. 5% and 76. 4% in MCF cells. The difference was significant compared with that before treatment ( P=0. 000 ) . However, the inhibitory effects were diminished after chemotherapeutic agent withdrawal. Cell viabilities were increased to 167. 9%, 212. 04% and 188. 66% in MDA-MB-231 cells at 48 h after withdrawal. At 72 h after withdrawal, cell viability was increased with a significant difference in three cell lines (all P values=0. 000). Expressions of CD44 and ALDH1 were most prevalent for MDA-MB-231, BT-483 and MCF-7 cells. ALDH1 mRNA level was significant higher in BT-483 ( HER-2 overexpression cell line) than MDA-MB-231 ( triple negative cell line ) ( P = 0. 012 ) . CD14 mRNA level in MCF-7 cells were significantly lower than that in MDA-MB-231 and BT-483 (P=0. 003, 0. 001). BT-483 showed significantly higher level of CD44 than MDA-MB-231 and MCF-7 cell line (P= 0.013, 0.020), and no significant difference was detected between MDA-MB-231 and MCF-7 breast cancer cells ( P=0. 955 ) . CD90 mRNA expressions were detected in MDA-MB-231 cells and MCF-7 cells, but not in BT-483 cells. Conclusion Some malignant

  16. The interaction between LYVE-1 with hyaluronan on the cell surface may play a role in the diversity of adhesion to cancer cells.

    Directory of Open Access Journals (Sweden)

    Yan Du

    Full Text Available Hyaluronan (HA, a simple disaccharide unit, can polymerize and is considered a primary component of the extracellular matrix, which has a wide range of biological functions. In recent years, HA was found on the surface of tumor cells. According to previous reports, differing HA content on the cell surface of tumor cells is closely related to lymph node metastases, but the mechanisms mediating this process remained unclear. This research intended to study the surface content of HA on tumor cells and analyze cell adhesive changes caused by the interaction between HA and its lymphatic endothelial receptor (LYVE-1. We screened and observed high HA content on HS-578T breast cells and low HA content on MCF-7 breast cells through particle exclusion, immunofluorescence and flow cytometry experiments. The expression of LYVE-1, the lymph-vessel specific HA receptor, was consistent with our previous report and enhanced the adhesion of HA(high-HS-578T cells to COS-7(LYVE-1(+ through HA in cell static adhesion and dynamic parallel plate flow chamber experiments. MCF-7 breast cells contain little HA on the surface; however, our results showed little adhesion difference between MCF-7 cells and COS-7(LYVE-1(+ and COS-7(LYVE-1(- cells. Similar results were observed concerning the adhesion of HS-578T cells or MCF-7 cells to SVEC4-10 cells. Furthermore, we observed for the first time that the cell surface HA content of high transfer tumor cells was rich, and we visualized the cross-linking of HA cable structures, which may activate LYVE-1 on lymphatic endothelial cells, promoting tumor adhesion. In summary, high-low cell surface HA content of tumor cells through the interaction with LYVE-1 leads to adhesion differences.

  17. Changes in cell morphology of Listeria monocytogenes and Shewanella putrefaciens resulting from the action of protamine.

    OpenAIRE

    Johansen, C; Gill, T; Gram, L

    1996-01-01

    Protamine, which is an antibacterial basic peptide, was shown to alter the cell morphology of Listeria monocytogenes and Shewanella putrefaciens. Atomic force microscopy revealed that protamine smoothed the surface of cells, formed holes in the cell envelope, and caused fusion of S. putrefaciens cells. Immunoelectron microscopy of protamine-treated cells of both L. monocytogenes and S. putrefaciens showed great damage to the cell wall and condensation of the cytoplasm. Respiration of the cell...

  18. Display of wasp venom allergens on the cell surface of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Poulsen Lars K

    2010-09-01

    Full Text Available Abstract Background Yeast surface display is a technique, where the proteins of interest are expressed as fusions with yeast surface proteins and thus remain attached to the yeast cell wall after expression. Our purpose was to study whether allergens expressed on the cell surface of baker's yeast Saccharomyces cerevisiae preserve their native allergenic properties and whether the yeast native surface glycoproteins interfere with IgE binding. We chose to use the major allergens from the common wasp Vespula vulgaris venom: phospholipase A1, hyaluronidase and antigen 5 as the model. Results The proteins were expressed on the surface as fusions with a-agglutinin complex protein AGA2. The expression was confirmed by fluorescent cytometry (FACS after staining the cells with antibody against a C-tag attached to the C-terminal end of the allergens. Phospholipase A1 and hyaluronidase retained their enzymatic activities. Phospholipase A1 severely inhibited the growth of the yeast cells. Antigen 5 - expressing yeast cells bound IgE antibodies from wasp venom allergic patient sera but not from control sera as demonstrated by FACS. Moreover, antigen 5 - expressing yeast cells were capable of mediating allergen-specific histamine release from human basophils. Conclusions All the three major wasp venom allergens were expressed on the yeast surface. A high-level expression, which was observed only for antigen 5, was needed for detection of IgE binding by FACS and for induction of histamine release. The non-modified S. cerevisiae cells did not cause any unspecific reaction in FACS or histamine release assay despite the expression of high-mannose oligosaccharides. In perspective the yeast surface display may be used for allergen discovery from cDNA libraries and possibly for sublingual immunotherapy as the cells can serve as good adjuvant and can be produced in large amounts at a low price.

  19. In situ observation of surface structures of cardiovascular endothelial cells with atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    Tong Yin; Jin Luo; YaMin Ma; Xiao-Long Ji; Yu-Sheng Zhao; Shi-Wen Wang

    2009-01-01

    Objective To observe the surface structures of cardiovascular endothelial cells in situ with atomic force microscope (AFM). Methods Fresh aorta and aortic valve were dissected from 10 healthy male New Zealand white rabbits. Before fixed in 1% formaldehyde, the fresh tissues were washed in the buffer phosphate solution. Under general microscope, the fixed aorta or valve was spread on the double side stick tape which had already been stuck on the glass slide. The intima of aorta or the aorta side of valve was towards upside. Then the specimen was dried under 37 degrees centigrade in an attemperator and was washed with pure water. After dried again, the specimen was loaded on the platform ofNanoScope llla AFM and was scanned in tapping mode with the scanning speed of 0.5 HZ. Results The surface structures of endothelial cell on the fixed and dried tissue could be obsserved clearly in situ with AFM. Aortic endothclial cells were large, branched and arranged sparsely and parallel to the direction of blood flow, whereas endothelial cells on aorta valve surface were small, less branched and arranged intensively and vertical to the direction of blood flow. When the scanning range was dwindled, granular ultra-structures could be observed on the surface of endothelial cells, and, as the scanning range was dwindled further, fissure and convolution could be seen on the surface of granules from aortic endothelial cells. Centre cavity and surrounding swelling volcano-like structure could be seen on the surface of granules from endothelial cells of aortic valve. Conclusions It's feasible to observe the surface ultra-structures of cardiovascular endothelial cells in situ with AFM and morphological information provided by A FM might be of clinical value in future histopathological diagnosis.

  20. Botswana water and surface energy balance research program. Part 1: Integrated approach and field campaign results

    Science.gov (United States)

    Vandegriend, A. A.; Owe, M.; Vugts, H. F.; Ramothwa, G. K.

    1992-01-01

    The Botswana water and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. Results of the first part of the program (Botswana 1) which ran from 1 Jan. 1988 - 31 Dec. 1990 are summarized. Botswana 1 consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive microwave research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel microwave radiometer microwave signatures. The integrated approach of both components in general are described and activities performed during the surface energy modeling component including the extensive field campaign are summarized. The results of the passive microwave component are summarized. The key of the field campaign was a multilevel approach, whereby measurements by various similar sensors were made at several altitudes and resolution. Data collection was performed at two adjacent sites of contrasting surface character. The following measurements were made: micrometeorological measurements, surface temperatures, soil temperatures, soil moisture, vegetation (leaf area index and biomass), satellite data, aircraft data, atmospheric soundings, stomatal resistance, and surface emissivity.

  1. On the problem about metrological authenticity of results of surface contamination radiometer checking

    International Nuclear Information System (INIS)

    Problems on metrological authenticity of surface contamination radiometer indications are considered. Effects of calibration device errors on the basis error of the radiometer has been investigated, taking the sources with strontium-90 and yttrium-90 as an example. Analysis of the results obtained has shown that the error, caused by deviation of the source active surface area from the nominal value, and the error, caused by irregularity of activity distribution over the source surface, make basic contributions into the error. Concrete measures to decrease systematic errors when checking radiometers as well as the methods for accounting their effects are suggested

  2. Bacterial Cell Surface Adsorption of Rare Earth Elements

    Science.gov (United States)

    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.

  3. Improved accuracy of cell surface shaving proteomics in Staphylococcus aureus using a false-positive control

    DEFF Research Database (Denmark)

    Solis, Nestor; Larsen, Martin Røssel; Cordwell, Stuart J

    2010-01-01

    with either trypsin or proteinase-K combined with LC-MS/MS. Trypsin-derived data were controlled using a "false-positive" strategy where cells were incubated without protease, removed by centrifugation and the resulting supernatants digested. Peptides identified in this fraction most likely result from cell...... lysis and were removed from the trypsin-shaved data set. We identified 42 predicted S. aureus COL surface proteins from 260 surface-exposed peptides. Trypsin and proteinase-K digests were highly complementary with ten proteins identified by both, 16 specific to proteinase-K treatment, 13 specific...

  4. Investigation of cell proliferative activity on the surface of the nanocomposite material produced by laser radiation

    Science.gov (United States)

    Zhurbina, N. N.; Kurilova, U. E.; Ickitidze, L. P.; Podgaetsky, V. M.; Selishchev, S. V.; Suetina, I. A.; Mezentseva, M. V.; Eganova, E. M.; Pavlov, A. A.; Gerasimenko, A. Y.

    2016-04-01

    A new method for the formation of composite nanomaterials based on multi-walled and single-walled carbon nanotubes (CNT) on a silicon substrate has been developed. Formation is carried out by ultrasound coating of a silicon substrate by homogenous dispersion of CNTs in the albumin matrix and further irradiation with the continuous laser beam with a wavelength of 810 nm and power of 5.5 watts. The high electrical conductivity of CNTs provides its structuring under the influence of the laser radiation electric field. The result is a scaffold that provides high mechanical strength of nanocomposite material (250 MPa). For in vitro studies of materials biocompatibility a method of cell growth microscopic analysis was developed. Human embryonic fibroblasts (EPP) were used as biological cells. Investigation of the interaction between nanocomposite material and cells was carried out by optical and atomic force microscopy depending on the time of cells incubation. The study showed that after 3 hours incubation EPP were fixed on the substrate surface, avoiding the surface of the composite material. However, after 24 hours of incubation EPP fix on the sample surface and then begin to grow and divide. After 72 hours of incubation, the cells completely fill the sample surface of nanocomposite material. Thus, a nanocomposite material based on CNTs in albumin matrix does not inhibit cell growth on its surface, and favours their growth. The nanocomposite material can be used for creating soft tissue implants

  5. Vaccines based on the cell surface carbohydrates of pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Jones Christopher

    2005-01-01

    Full Text Available Glycoconjugate vaccines, in which a cell surface carbohydrate from a micro-organism is covalently attached to an appropriate carrier protein are proving to be the most effective means to generate protective immune responses to prevent a wide range of diseases. The technology appears to be generic and applicable to a wide range of pathogens, as long as antibodies against surface carbohydrates help protect against infection. Three such vaccines, against Haemophilus influenzae type b, Neisseria meningitidis Group C and seven serotypes of Streptococcus pneumoniae, have already been licensed and many others are in development. This article discusses the rationale for the development and use of glycoconjugate vaccines, the mechanisms by which they elicit T cell-dependent immune responses and the implications of this for vaccine development, the role of physicochemical methods in the characterisation and quality control of these vaccines, and the novel products which are under development.

  6. Adjustment of surface chemical and physical properties with functionalized polymers to control cell adhesion

    Science.gov (United States)

    Zhou, Zhaoli

    Cell-surface interaction is crucial in many cellular functions such as movement, growth, differentiation, proliferation and survival. In the present work, we have developed several strategies to design and prepare synthetic polymeric materials with selected cues to control cell attachment. To promote neuronal cell adhesion on the surfaces, biocompatible, non-adhesive PEG-based materials were modified with neurotransmitter acetylcholine functionalities to produce hydrogels with a range of porous structures, swollen states, and mechanical strengths. Mice hippocampal cells cultured on the hydrogels showed differences in number, length of processes and exhibited different survival rates, thereby highlighting the importance of chemical composition and structure in biomaterials. Similar strategies were used to prepare polymer brushes to assess how topographical cues influence neuronal cell behaviors. The brushes were prepared using the "grown from" method through surface-initiated atom transfer radical polymerization (SI-ATRP) reactions and further patterned via UV photolithography. Protein absorption tests and hippocampal neuronal cell culture of the brush patterns showed that both protein and neuronal cells can adhere to the patterns and therefore can be guided by the patterns at certain length scales. We also prepared functional polymers to discourage attachment of undesirable cells on the surfaces. For example, we synthesized PEG-perfluorinated alkyl amphiphilic surfactants to modify polystyrene-block-poly(ethylene-ran-butylene)- block-polyisoprene (SEBI or K3) triblock copolymers for marine antifouling/fouling release surface coatings. Initial results showed that the polymer coated surfaces can facilitate removal of Ulva sporelings on the surfaces. In addition, we prepared both bioactive and dual functional biopassive/bioactive antimicrobial coatings based on SEBI polymers. Incubating the polymer coated surfaces with gram-positive bacteria (S. aureus), gram

  7. Calcium influences sensitivity to growth inhibition induced by a cell surface sialoglycopeptide

    Science.gov (United States)

    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.

  8. Extraction of cell surface-associated proteins from living yeast cells.

    NARCIS (Netherlands)

    F.M. Klis; M. de Jong; S. Brul; P.W.J. de Groot

    2007-01-01

    To extract cell surface-associated proteins from living fungal cells, reducing agents such as beta-mercaptoethanol and dithiothreitol are often used. We show here that both compounds are moderately lipophilic and may perturb the plasma membrane, thus causing the release of cytosolic proteins, especi

  9. A Simple Hydrophilic Treatment of SU-8 Surfaces for Cell Culturing and Cell Patterning

    DEFF Research Database (Denmark)

    Wang, Zhenyu; Stangegaard, Michael; Dufva, Hans Martin;

    2005-01-01

    SU-8, an epoxy-based photoresist, widely used in constitution different mTAS systems, is incompatible with mammalian cell adhesion and culture in its native form. Here, we demonstrate a simple, cheap and robust two-step method to render a SU-8 surface hydrophilic and compatible with cell culture...

  10. Methods To Identify Aptamers against Cell Surface Biomarkers

    OpenAIRE

    Frédéric Ducongé; Daniel Miotto Dupont; Agnes Cibiel

    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 cytometr...

  11. Biointerface: protein enhanced stem cells binding to implant surface.

    Science.gov (United States)

    Chrzanowski, W; Kondyurin, A; Lee, Jae Ho; Lord, Megan S; Bilek, M M M; Kim, Hae-Won

    2012-09-01

    The number of metallic implantable devices placed every year is estimated at 3.7 million. This number has been steadily increasing over last decades at a rate of around 8 %. In spite of the many successes of the devices the implantation of biomaterial into tissues almost universally leads to the development of an avascular sac, which consists of fibrous tissue around the device and walls off the implant from the body. This reaction can be detrimental to the function of implant, reduces its lifetime, and necessitates repeated surgery. Clearly, to reduce the number of revision surgeries and improve long-term implant function it is necessary to enhance device integration by modulating cell adhesion and function. In this paper we have demonstrated that it is possible to enhance stem cell attachment using engineered biointerfaces. To create this functional interface, samples were coated with polymer (as a precursor) and then ion implanted to create a reactive interface that aids the binding of biomolecules--fibronectin. Both AFM and XPS analyses confirmed the presence of protein layers on the samples. The amount of protein was significant greater for the ion implanted surfaces and was not disrupted upon washing with detergent, hence the formation of strong bonds with the interface was confirmed. While, for non ion implanted surfaces, a decrease of protein was observed after washing with detergent. Finally, the number of stem cells attached to the surface was enhanced for ion implanted surfaces. The studies presented confirm that the developed bionterface with immobilised fibronectin is an effective means to modulate stem cell attachment. PMID:22714559

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

    DEFF Research Database (Denmark)

    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 re...... 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....

  13. Smooth Muscle Cell Functionality on Collagen Immobilized Polycaprolactone Nanowire Surfaces

    OpenAIRE

    Victoria Leszczak; Baskett, Dominique A.; Popat, Ketul C.

    2014-01-01

    Inhibition of smooth muscle cell (SMC) proliferation and preservation of a differentiated state are important aspects in the management, avoidance and progression of vascular diseases. An understanding of the interaction between SMCs and the biomaterial involved is essential for a successful implant. In this study, we have developed collagen immobilized nanostructured surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of human aortic SMCs. The nanow...

  14. The surface nanostructures of titanium alloy regulate the proliferation of endothelial cells

    Directory of Open Access Journals (Sweden)

    Min Lai

    2014-02-01

    Full Text Available To investigate the effect of surface nanostructures on the behaviors of human umbilical vein endothelial cells (HUVECs, surface nanostructured titanium alloy (Ti-3Zr2Sn-3Mo-25Nb, TLM was fabricated by surface mechanical attrition treatment (SMAT technique. Field emission scanning electron microscopy (FE-SEM, atomic force microscopy (AFM, transmission electron microscopy (TEM and X-ray diffraction (XRD were employed to characterize the surface nanostructures of the TLM, respectively. The results demonstrated that nano-crystalline structures with several tens of nanometers were formed on the surface of TLM substrates. The HUVECs grown onto the surface nanostructured TLM spread well and expressed more vinculin around the edges of cells. More importantly, HUVECs grown onto the surface nanostructured TLM displayed significantly higher (p < 0.01 or p < 0.05 cell adhesion and viabilities than those of native titanium alloy. HUVECs cultured on the surface nanostructured titanium alloy displayed significantly higher (p < 0.01 or p < 0.05 productions of nitric oxide (NO and prostacyclin (PGI2 than those of native titanium alloy, respectively. This study provides an alternative for the development of titanium alloy based vascular stents.

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

    Science.gov (United States)

    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

  16. Force Balance and Membrane Shedding at the Red-Blood-Cell Surface

    Science.gov (United States)

    Sens, Pierre; Gov, Nir

    2007-01-01

    During the aging of the red-blood cell, or under conditions of extreme echinocytosis, membrane is shed from the cell plasma membrane in the form of nanovesicles. We propose that this process is the result of the self-adaptation of the membrane surface area to the elastic stress imposed by the spectrin cytoskeleton, via the local buckling of membrane under increasing cytoskeleton stiffness. This model introduces the concept of force balance as a regulatory process at the cell membrane and quantitatively reproduces the rate of area loss in aging red-blood cells.

  17. Suppressed proliferation of mouse osteoblast-like cells by a rough-surfaced substrate leads to low differentiation and mineralization

    International Nuclear Information System (INIS)

    The cellular responses of mouse osteoblast-like MC3T3-E1 cells to the surface roughness were examined in the sequential events of cell adhesion, proliferation, differentiation, and mineralization. The cells were plated and cultured on sandblasted borosilicate glass slideslips with different surface roughnesses. DNA synthesis at day 1 after plating and the cell number at day 5 significantly decreased as the surface roughness increased. The suppressed cell proliferation on the rough-surfaced substrates, closely related to the round cell morphology, caused underdeveloped intercellular contacts via the gap junction due to the low population of neighboring cells. Expressions of the representative osteoblastic genes at day 14, alkaline phosphatase activity at day 21, and mineralization at day 28 were markedly reduced on the rough-surfaced substrates. These results clearly indicated that the reduced cell differentiation and mineralization resulted from the early cellular responses of the suppressed cell proliferation depending on the surface roughness and the consequent poor intercellular communication. The specific changes in the early gene expression profiles at day 1, depending on the surface roughness, were examined by a large-scale analysis of the gene expression using a mouse DNA chip. The ribosomal protein S6 kinase polypeptide 1 gene, which is a cell growth-related gene involved in the PI3-kinase/Akt pathway, was found to be the most down-regulated among the 4277 screened genes.

  18. Cytomegalovirus m154 hinders CD48 cell-surface expression and promotes viral escape from host natural killer cell control.

    Directory of Open Access Journals (Sweden)

    Angela Zarama

    2014-03-01

    Full Text Available Receptors of the signalling lymphocyte-activation molecules (SLAM family are involved in the functional regulation of a variety of immune cells upon engagement through homotypic or heterotypic interactions amongst them. Here we show that murine cytomegalovirus (MCMV dampens the surface expression of several SLAM receptors during the course of the infection of macrophages. By screening a panel of MCMV deletion mutants, we identified m154 as an immunoevasin that effectively reduces the cell-surface expression of the SLAM family member CD48, a high-affinity ligand for natural killer (NK and cytotoxic T cell receptor CD244. m154 is a mucin-like protein, expressed with early kinetics, which can be found at the cell surface of the infected cell. During infection, m154 leads to proteolytic degradation of CD48. This viral protein interferes with the NK cell cytotoxicity triggered by MCMV-infected macrophages. In addition, we demonstrate that an MCMV mutant virus lacking m154 expression results in an attenuated phenotype in vivo, which can be substantially restored after NK cell depletion in mice. This is the first description of a viral gene capable of downregulating CD48. Our novel findings define m154 as an important player in MCMV innate immune regulation.

  19. Relationship between antibacterial activity of chitosan and surface characteristics of cell wall

    Institute of Scientific and Technical Information of China (English)

    Ying-chien CHUNG; Ya-ping SU; Chiing-chang CHEN; Guang JIA; Huey-lan WANG; J C Gaston WU; Jaung-geng LIN

    2004-01-01

    AIM: Five representative waterborne pathogens were used to illustrate the relationship between chitosan's antibacterial activity and the surface characteristics of the bacterial cell wall. METHODS: Chitosan was prepared with averaged 75 % or 95 % deacetylated degree to examine its antibacterial activity against waterborne pathogens.Fresh microbial inoculants for the antibacterial assessment were prepared on nutrient agar at 37 °C for 24 h. The evaluation items of antibacterial mechanism included hydrophilicity and negative charge analysis of cell surface, and adsorptive characteristics of chitosan to bacterial cell. All the experiments were applied in triplicate tests at least.RESULTS: Although cell wall hydrophilicity was similar among Gram-negative bacteria, the distribution of negative charge on their cell surfaces was quite different. More negatively charged cell surfaces had a greater interaction with chitosan, a phenomenon further confirmed by transmission electron micrography (TEM). CONCLUSION:Results showed the hydrophilicity in Gram-negative bacteria was much higher than in Gram-positive ones. The correlation coefficient 0.988 between the amount of absorbed chitosan and its inhibition efficiency indicated a close relationship.

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

    Science.gov (United States)

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

    2016-04-01

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

  1. Role of calcium in growth inhibition induced by a novel cell surface sialoglycopeptide

    Science.gov (United States)

    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.

  2. Pancreatic hormones are expressed on the surfaces of human and rat islet cells through exocytotic sites

    DEFF Research Database (Denmark)

    Larsson, L I; Hutton, J C; Madsen, O D;

    1989-01-01

    . Electron microscopy reveals the labeling to occur at sites of exocytotic granule release, involving the surfaces of extruded granule cores. The surfaces of islet cells were labeled both by polyclonal and monoclonal antibodies, excluding that receptor-interacting, anti-idiotypic hormone antibodies were...... for these results. It is concluded that the staining reflects interactions between the appropriate antibodies and exocytotic sites of hormone release....

  3. Surface electromagnetic impedance and geomagnetic activity: results of long term observation

    Science.gov (United States)

    Lemperger, István; Menvielle, Menvielle; Wesztergom, Viktor; Bencze, Pál; Szendrői, Judit; Novák, Attila; Kis, Árpád; Szalai, Sándor

    2014-05-01

    The magnetotelluric (MT) method is one of the most useful geophysical tool to discover even the deep subsurface structures. The target function of the MT data processing is the surface electromagnetic (EM) impedance. In case of practical MT exploration the surface EM impedance is computed based on a simplification related to the nature of the ionospheric source of the surface EM signals. Assuming that the ionospheric current systems result in homogeneous surface electromagnetic variations, the uncertainty of the computed surface electromagnetic impedance tensor depends only the duration of the EM observation. However the surface EM field can only be approached by plane waves in certain time periods and besides given uncertainty. The EM impedance may be sensitive to magnetospheric and -indirectly- interplanetary circumstances and solar activity. Four years continuous observation of telluric and surface geomagnetic components allowed to perform a representative survey to discover if geomagnetic activity has any effect on observed EM impedance tensor. Geomagnetic indices (Dst, ULF-index, ASY-H, SYM-H) have been used to classify dates according to geomagnetic activity. Processing to estimate the mean surface EM impedance tensor has been performed in each dataset, each class separately. The sensitivity and the characteristics of the answer of the EM impedance tensor to the geomagnetic disturbances seems to be definite. This presentation aims to briefly summarize the preliminary results of our study based on the unique dataset of the Széchenyi István Geophysical Obsevatory (Intermagnet code:NCK). In addition, pointing out the limitations of the routine way of practical MT data processing and interpretation is an important duty of this study. This study was supported by the TAMOP-4.2.2.C-11/1/KONV-2012-0015 (Earth-system) project sponsored by the EU and European Social Foundation.

  4. Cell-surface acceleration of urokinase-catalyzed receptor cleavage

    DEFF Research Database (Denmark)

    Høyer-Hansen, G; Ploug, M; Behrendt, N;

    1997-01-01

    The urokinase-type plasminogen activator (uPA) binds to a specific cell-surface receptor, uPAR. On several cell types uPAR is present both in the full-length form and a cleaved form, uPAR(2+3), which is devoid of binding activity. The formation of uPAR(2+3) on cultured U937 cells is either directly...... by a prior incubation of the cells with uPA inactivated by diisopropyl fluorophosphate, demonstrating a requirement for specific receptor binding of the active uPA to obtain the high-efficiency cleavage of cell-bound uPAR. Furthermore, amino-terminal sequence analysis revealed that uPAR(2+3), purified from U......937 cell lysates, had the same amino termini as uPAR(2+3), generated by uPA in a purified system. In both cases cleavage had occurred at two positions in the hinge region connecting domain 1 and 2, between Arg83-Ala84 and Arg89-Ser90, respectively. The uPA-catalyzed cleavage of uPAR is a new negative...

  5. Transition state theory description of surface self-diffusion: Comparison with classical trajectory results

    International Nuclear Information System (INIS)

    We have computed the surface self-diffusion constants on four different crystal faces [fcc(111), fcc(100), bcc(110), and bcc(211)] using classical transition state theory methods. These results can be compared directly with previous classical-trajectory results which used the same Lennard-Jones 6-12 potential and template model; the agreement is good, though dynamical effects are evident for the fcc(111) and bcc(110) surfaces. Implications are discussed for low-temperature diffusion studies, which are inaccessible to direct molecular dynamics, and the use of ab initio potentials rather than approximate pairwise potentials

  6. Biocompatible, smooth, plasma-treated nickel-titanium surface--an adequate platform for cell growth.

    Science.gov (United States)

    Chrzanowski, W; Szade, J; Hart, A D; Knowles, J C; Dalby, M J

    2012-02-01

    High nickel content is believed to reduce the number of biomedical applications of nickel-titanium alloy due to the reported toxicity of nickel. The reduction in nickel release and minimized exposure of the cell to nickel can optimize the biocompatibility of the alloy and increase its use in the application where its shape memory effects and pseudoelasticity are particularly useful, e.g., spinal implants. Many treatments have been tried to improve the biocompatibility of Ni-Ti, and results suggest that a native, smooth surface could provide sufficient tolerance, biologically. We hypothesized that the native surface of nickel-titanium supports cell differentiation and insures good biocompatibility. Three types of surface modifications were investigated: thermal oxidation, alkali treatment, and plasma sputtering, and compared with smooth, ground surface. Thermal oxidation caused a drop in surface nickel content, while negligible chemistry changes were observed for plasma-modified samples when compared with control ground samples. In contrast, alkali treatment caused significant increase in surface nickel concentration and accelerated nickel release. Nickel release was also accelerated in thermally oxidized samples at 600 °C, while in other samples it remained at low level. Both thermal oxidation and alkali treatment increased the roughness of the surface, but mean roughness R(a) was significantly greater for the alkali-treated ones. Ground and plasma-modified samples had 'smooth' surfaces with R(a)=4 nm. Deformability tests showed that the adhesion of the surface layers on samples oxidized at 600 °C and alkali treatment samples was not sufficient; the layer delaminated upon deformation. It was observed that the cell cytoskeletons on the samples with a high nickel content or release were less developed, suggesting some negative effects of nickel on cell growth. These effects were observed primarily during initial cell contact with the surface. The most favorable

  7. The characteristics of Ishikawa endometrial cancer cells are modified by substrate topography with cell-like features and the polymer surface

    Directory of Open Access Journals (Sweden)

    Tan LH

    2015-08-01

    those on a flat pST surface. This method, which provided substrates in vitro with cell-like features, enabled the study of effects of topographies that are similar to those experienced by cells in vivo. The observations establish that such a physical environment has an effect on cancer cell behavior independent of the characteristics of the substrate. The results support the concept that the physical topography of a cell’s environment may modulate crucial oncological signaling pathways; this suggests the possibility of cancer therapies that target pathways associated with the response to mechanical stimuli. Keywords: surface characteristics, cell culture platforms, physical microenvironment, cell response, drug targets, mechanical forces

  8. Characterization of the osteogenic potential of mesenchymal stem cells from human periodontal ligament based on cell surface markers

    Institute of Scientific and Technical Information of China (English)

    Ruth Alvarez; Hye-Lim Lee; Cun-Yu Wang; Christine Hong

    2015-01-01

    Mesenchymal stem cell (MSC)-mediated therapy has been shown to be clinically effective in regenerating tissue defects. For improved regenerative therapy, it is critical to isolate homogenous populations of MSCs with high capacity to differentiate into appropriate tissues. The utilization of stem cell surface antigens provides a means to identify MSCs from various tissues. However, few surface markers that consistently isolate highly regenerative MSCs have been validated, making it challenging for routine clinical applications and making it all the more imperative to identify reliable surface markers. In this study, we used three surface marker combinations:CD51/CD140a, CD271, and STRO-1/CD146 for the isolation of homogenous populations of dental mesenchymal stem cells (DMSCs) from heterogeneous periodontal ligament cells (PDLCs). Fluorescence-activated cell sorting analysis revealed that 24%of PDLCs were CD511/CD140a1, 0.8%were CD2711, and 2.4%were STRO-11/CD1461. Sorted cell populations were further assessed for their multipotent properties by inducing osteogenic and chondrogenic differentiation. All three subsets of isolated DMSCs exhibited differentiation capacity into osteogenic and chondrogenic lineages but with varying degrees. CD2711 DMSCs demonstrated the greatest osteogenic potential with strong induction of osteogenic markers such as DLX5, RUNX2, and BGLAP. Our study provides evidence that surface marker combinations used in this study are sufficient markers for the isolation of DMSCs from PDLCs. These results provide important insight into using specific surface markers for identifying homogenous populations of DMSCs for their improved utilization in regenerative medicine.

  9. A surface-modified biodegradable urethral scaffold seeded with urethral epithelial cells

    Institute of Scientific and Technical Information of China (English)

    FU Wei-jun; ZHANG Xu; WANG Zhong-xin; LI Gang; ZHANG Bing-hong; ZHANG Lei; HU Kun; HONG Bao-fa; WANG Xiao-xiong; CUI Fu-zhai

    2011-01-01

    Background Efficient cell adhesion and proliferation is a central issue in cell-based tissue engineering, which offers great promise for repair of urethral defects or strictures. This study evaluated the adhesion and growth of rabbit uroepithelium on a surface-modified three-dimensional poly-L-lactic acid (PLLA) scaffold.Methods Urethral mucosa were harvested from male New Zealand rabbits and the urothelium were dissociated and then cultured. Immunocytochemistry on cultured uroepithelium for pancytokeratin and uroplakin Ⅱ and TE-7 confirmed pure populations. After in vitro proliferation, cells were seeded onto a surface-modified urethral scaffold with non-knitted filaments. The morphology and viability of the cells were examined by immunohistochemical and fluorescence staining.Inverted and scanning microscopes were used to document cell growth and adhesion.Results Three to five days after primary culture, the uroepithelial cells gradually became confluent, assuming a cobblestone pattern. The filaments of the urethral scaffold had excellent biocompatibility and allowed growth of the uroepithelium, without affecting viability. The uroepithelial cells adhered to and grew well on the scaffold. After 3-7 days,the cells grew vigorously and meshes of the scaffold were full of uroepitheliums.Conclusions The surface-modified urethral scaffold with non-knitted filaments allows the growth of uroepithelium and can serve as a carrier for the tissue engineering of urethra.

  10. Development of living cell force sensors for the interrogation of cell surface interactions

    Science.gov (United States)

    Brown, Scott Chang

    The measurement of cell surface interactions, or cell interaction forces, are critical for the early diagnosis and prevention of disease, the design of targeted drug and gene delivery vehicles, the development of next-generation implant materials, and much more. However, the technologies and devices that are currently available are highly limited with respect to the dynamic force range over which they can measure cell-cell or cell-substratum interactions, and with their ability to adequately mimic biologically relevant systems. Consequently, research efforts that involve cell surface interactions have been limited. In this dissertation, existing tools for research at the nanoscale (i.e., atomic force microscopy microcantilevers) are modified to develop living cell force sensors that allow for the highly sensitive measurement of cell-mediated interactions over the entire range of forces expected in biotechnology (and nano-biotechnology) research (from a single to millions of receptor-ligand bonds). Several force sensor motifs have been developed that can be used to measure interactions using single adherent cells, single suspension culture cell, and cell monolayers (tissues) over a wide range of interaction conditions (e.g., approach velocity, shear rate, contact time) using a conventional atomic force microscope. This new tool has been applied to study the pathogenesis of spontaneous pneumothorax and the interaction of cells with 14 man-made interfaces. Consequently, a new hypothesis of the interactions that manifest spontaneous pneumothorax has been developed. Additionally, these findings have the potential to lead to the development of tools for data mining materials and surfaces for unique cell interactions that could have an immense societal impact.

  11. Short-chain ceramides depress integrin cell surface expression and function in colorectal cancer cells.

    Science.gov (United States)

    Morad, Samy A F; Bridges, Lance C; Almeida Larrea, Alex D; Mayen, Anthony L; MacDougall, Matthew R; Davis, Traci S; Kester, Mark; Cabot, Myles C

    2016-07-01

    Colorectal cancer (CRC) is highly metastatic, significantly so to liver, a characteristic that embodies one of the most challenging aspects of treatment. The integrin family of cell-cell and cell-matrix adhesion receptors plays a central role in migration and invasion, functions that underlie metastatic potential. In the present work we sought to determine the impact of ceramide, which plays a key modulatory role in cancer suppression, on integrin cell surface expression and function in CRC cells in order to reveal possible ceramide-centric effects on tumor cell motility. Human CRC cells LoVo, HT-29, and HCT-116 were employed, which represent lines established from primary and metastatic sites. A cell-permeable, short-chain analog, C6-ceramide, was used as ceramide mimic. Exposure of cells to C6-ceramide (24 h) promoted a dose-dependent (2.5-10 µM) decrease in the expression of cell surface β1 and β4 integrin subunits in all cell lines; at 10 µM C6-ceramide, the decreases ranged from 30 to 50% of the control. Expression of cell surface αVβ6 integrin, which is associated with advanced invasion in CRC, was also suppressed by C6-ceramide. Decreases in integrin expression translated to diminished cellular adhesion, 50% of the control at 5 µM C6-ceramide, and markedly reduced cellular migration, approximately 30-40% of the control in all cell lines. Physicochemical examination revealed potent efficacy of nano-formulated C6-ceramide, but inferior activity of dihydro-C6-ceramide and L-C6-ceramide, compared to the unsaturated counterpart and the natural d-enantiomer, respectively. These studies demonstrate novel actions of ceramides that may have application in suppression of tumor metastasis, in addition to their known tumor suppressor effects. PMID:27045476

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

    Science.gov (United States)

    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

  13. Spatial organization of mesenchymal stem cells in vitro--results from a new individual cell-based model with podia.

    Directory of Open Access Journals (Sweden)

    Martin Hoffmann

    Full Text Available Therapeutic application of mesenchymal stem cells (MSC requires their extensive in vitro expansion. MSC in culture typically grow to confluence within a few weeks. They show spindle-shaped fibroblastoid morphology and align to each other in characteristic spatial patterns at high cell density. We present an individual cell-based model (IBM that is able to quantitatively describe the spatio-temporal organization of MSC in culture. Our model substantially improves on previous models by explicitly representing cell podia and their dynamics. It employs podia-generated forces for cell movement and adjusts cell behavior in response to cell density. At the same time, it is simple enough to simulate thousands of cells with reasonable computational effort. Experimental sheep MSC cultures were monitored under standard conditions. Automated image analysis was used to determine the location and orientation of individual cells. Our simulations quantitatively reproduced the observed growth dynamics and cell-cell alignment assuming cell density-dependent proliferation, migration, and morphology. In addition to cell growth on plain substrates our model captured cell alignment on micro-structured surfaces. We propose a specific surface micro-structure that according to our simulations can substantially enlarge cell culture harvest. The 'tool box' of cell migratory behavior newly introduced in this study significantly enhances the bandwidth of IBM. Our approach is capable of accommodating individual cell behavior and collective cell dynamics of a variety of cell types and tissues in computational systems biology.

  14. Disrupting the oncogenic synergism between nucleolin and Ras results in cell growth inhibition and cell death.

    Directory of Open Access Journals (Sweden)

    Sari Schokoroy

    Full Text Available BACKGROUND: The ErbB receptors, Ras proteins and nucleolin are major contributors to malignant transformation. The pleiotropic protein nucleolin can bind to both Ras protein and ErbB receptors. Previously, we have demonstrated a crosstalk between Ras, nucleolin and the ErbB1 receptor. Activated Ras facilitates nucleolin interaction with ErbB1 and stabilizes ErbB1 levels. The three oncogenes synergistically facilitate anchorage independent growth and tumor growth in nude mice. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we used several cancer cell lines. The effect of Ras and nucleolin inhibition was determined using cell growth, cell death and cell motility assays. Protein expression was determined by immunohistochemistry. We found that inhibition of Ras and nucleolin reduces tumor cell growth, enhances cell death and inhibits anchorage independent growth. Our results reveal that the combined treatment affects Ras and nucleolin levels and localization. Our study also indicates that Salirasib (FTS, Ras inhibitor reduces cell motility, which is not affected by the nucleolin inhibitor. CONCLUSIONS/SIGNIFICANCE: These results suggest that targeting both nucleolin and Ras may represent an additional avenue for inhibiting cancers driven by these oncogenes.

  15. Niemann Pick type C cells show cholesterol dependent decrease of APP expression at the cell surface its increased processing through the ?-secretase pathway

    OpenAIRE

    Malnar, Martina; KOŠIČEK, MARKO; Mitterreiter, Stefan; Omerbašić, Damir; Lichtenthaler, Stefan F.; Goate, Alison; Hećimović, Silva

    2010-01-01

    Abstract The link between cholesterol and Alzheimer's disease has recently been revealed in Niemann Pick type C disease. We found that NPC1-/- cells show decreased expression of APP at the cell surface and increased processing of APP through the ?-secretase pathway resulting in increased C99, sAPP? and intracellular A?40 levels. This effect is dependent on increased cholesterol levels, since cholesterol depletion reversed cell surface APP expression and lowered A?/C99 levels in NPC...

  16. Plant lectin, ATF1011, on the tumor cell surface augments tumor-specific immunity through activation of T cells specific for the lectin.

    Science.gov (United States)

    Yoshimoto, R; Kondoh, N; Isawa, M; Hamuro, J

    1987-01-01

    The possibility that a plant lectin as a carrier protein would specifically activate T cells, resulting in the augmentation of antitumor immunity was investigated. ATF1011, a nonmitogenic lectin for T cells purified from Aloe arborescens Mill, bound equally to normal and tumor cells. ATF1011 binding on the MM102 tumor cell surfaces augmented anti-trinitrophenyl (TNP) antibody production of murine splenocytes when the mice were primarily immunized with TNP-conjugated MM102 tumor cells. The alloreactive cytotoxic T cell response was also augmented by allostimulator cells binding ATF1011 on the cell surfaces. These augmented responses may be assumed to be mediated by the activation of helper T cells recognizing ATF1011 as a carrier protein. Killer T cells were induced against ATF1011 antigen in the H-2 restricted manner using syngeneic stimulator cells bearing ATF1011 on the cell surfaces. When this lectin was administered intralesionally into the tumors, induction of cytotoxic effector cells was demonstrated. These results suggest that intralesionally administered ATF1011 binds to the tumor cell membrane and activates T cells specific for this carrier lectin in situ, which results in the augmented induction of systemic antitumor immunity. PMID:3496156

  17. STUDY ON GLYCOCONJUGATE CHANGES ON CELL SURFACE IN PROGRESSIVE DEVELOPMENT OF PULMONARY TUMOR

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-mei; SHAN Jun; CHEN Zhuo-huai

    2002-01-01

    Aim: To investigate glycoconjugate changes on the cell surface of proliferative lesions and neoplasms of mice lungs at various stages of tumorigenesis, the relation between progressive development of mouse pulmonary tumors and expression of cell surface saccharide. Materials and methods: Thirty - one male A/J strain mice at 5 weeks of age were treated intraperitoneally with a single injection of 20 - methylcholanthrene (20 - MC), 292 pulmonary lesions including 31 hyperplasias, 145 alveolar adenomas, 61 papillary adenomas, 55 papillary adenocarcinomas and their combined type were obtained. The binding affinities of cells in normal respiratory epithelia and in proliferative lesions to four peroxidases - conjugated lectins, Maclura pomifera agglutinin (MPA), Arachis hypogea agglutinin (PNA), Ricinus communis agglutinin (RCA), and wheat germ agglutinin (WGA) were examined. Results: Cells of hyperplasia and alveolar adenoma showed fairly strong affinity to all the four lectins. However, part of papillary adenoma cells and greater part of papillary adenocarcinoma cells lost their binding affinity to MPA, PNA, and RCA, but not to WGA. The bindings of MPA, PNA and RNA were detected predominently on the luminal surfaces of benign tumors but not on the luminal surfaces of malignant tumors. WGA might bind to varied types of benign and malignant tumors. Pretreated with neuraminidase, the lesions enhanced the staining intensity for the four lectins, the binding sites of WGA to malignant tumor cells were numerous. A distinct difference in lectin binding affinity between hyperplasia / alveolar adenoma/papillary adenoma and papillary adenocarcinoma was clearly shown( x2 = 46.89, P < 0.01, x2 = 36.77, P < 0.01 and x2 = 52.87, P < 0.01 ) in this experiment. The complex glycoconjugates on the cell surface of malignant and benign lesions during the development of pulmonary tumor were changed,malignant tumor cells differed from the surface of benign tumor cells, the levels of

  18. Retargeting of natural killer-cell cytolytic activity to ErbB2-expressing cancer cells results in efficient and selective tumor cell destruction.

    Science.gov (United States)

    Uherek, Christoph; Tonn, Torsten; Uherek, Barbara; Becker, Sven; Schnierle, Barbara; Klingemann, Hans-Georg; Wels, Winfried

    2002-08-15

    The continuously growing natural killer (NK) cell line NK-92 is highly cytotoxic against malignant cells of various origins without affecting normal human cells. Based on this selectivity, the potential of NK-92 cells for adoptive therapy is currently being investigated in phase I clinical studies. To further enhance the antitumoral activity of NK-92 cells and expand the range of tumor entities suitable for NK-92-based therapies, here by transduction with a retroviral vector we have generated genetically modified NK-92 cells expressing a chimeric antigen receptor specific for the tumor-associated ErbB2 (HER2/neu) antigen, which is overexpressed by many tumors of epithelial origin. The chimeric antigen receptor consists of the ErbB2-specific scFv(FRP5) antibody fragment, a flexible hinge region derived from CD8, and transmembrane and intracellular regions of the CD3 zeta chain. Transduced NK-92-scFv(FRP5)-zeta cells express high levels of the fusion protein on the cell surface as determined by fluorescence-activated cell-scanning (FACS) analysis. In europium release assays, no difference in cytotoxic activity of NK-92 and NK-92-scFv(FRP5)-zeta cells toward ErbB2-negative targets was found. However, even at low effector-to-target ratios, NK-92-scFv(FRP5)-zeta cells specifically and efficiently lysed established and primary ErbB2-expressing tumor cells that were completely resistant to cytolytic activity of parental NK-92 cells. These results demonstrate that efficient retargeting of NK-92 cytotoxicity can be achieved and might allow the generation of potent cell-based therapeutics for the treatment of ErbB2-expressing malignancies. PMID:12149207

  19. Long-wave textural components in sheet surfaces and their influence on painting results

    Energy Technology Data Exchange (ETDEWEB)

    Deutscher, O. [Betriebsforschungsinstitut (BFI) VDEh-Institut fuer Angewandte Forschung GmbH, Duesseldorf (Germany)

    2005-07-01

    Long-wave textural components in the top coat of cars are undesirable as they may result in the ''so-called orange-peel effect'', which diminishes the optical performance of the product and is perceived as poor quality by consumers. Known influencing factors include the chosen paint system, the application method, the conditions under which the paint is applied, and the waviness in the sheet surface. Based on investigations made in close cooperation with representatives of the steel, automotive and paint industry the connection of steel sheet surface and top coat waviness was analyzed. The main cause of waviness in steel sheets seems to be the waviness in the surface of work rolls that are imprinted in the steel strip surface during the skin passing process. The condition of the strip before skin passing does not appear to have any noticeable effect. The within Europe varying parameters characterizing the surface waviness of steel sheets are examined with reference to their validity to assess the paintability with regard to the ''orange peel effect''. For this the results of both laboratory paintings and paintings in paint shops of different car producers are assessed. The most meaningful parameter characterizing the waviness seems to be the mean value of the power spectrum. As more practical parameters the Wca value and the sSt value show sufficient correlations too. (orig.)

  20. Distribution of anionic groups at the cell surface of different Sporothrix schenckii cell types.

    Science.gov (United States)

    Benchimol, M; de Souza, W; Travassos, L R

    1979-06-01

    The distribution of anionic groups at the cell surface of yeastlike forms, hyphae, and conidia of Sporothrix schenckii was studied by staining with colloidal iron hydroxide and cationized ferritin. By using colloidal iron hydroxide it was shown that the external cell wall layer of one strain (strain 1099.18) could be resolved into two reactive sublayers and that these layers were present in many but not all cells of the same population. In contrast, most cells of another strain (strain 1099.12) were stained by colloidal iron hydroxide, but only one reactive layer was seen. Acidic layers of the yeastlike forms of the two strains were much thicker than those of conidia and hyphae. By the cationized ferritin staining procedure it was observed that the acidic layers of yeast forms sloughed off of cells, probably due to cell-cell or cell-medium attrition in shaken submerged cultures or to a process by which the outer layers detach from cells as they are replaced by newly synthesized ones. The colloidal iron hydroxide- and cationized ferritin-reactive cell surface layers of S. schenckii correspond to the previously described (L. R. Travassos et al., Exp. Mycol. 1:293-305, 1977) concanavalin A-reactive peptidorhamnomannan complexes, and their reactivity is probably due to the presence of acidic amino acids of low pK values rather than to glucuronic acid units.

  1. Effect of surface viscosity, anchoring energy, and cell gap on the response time of nematic liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Souza, R.F. de [Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020 - 900 Maringá –PR (Brazil); Yang, D.-Ke [Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242 (United States); Lenzi, E.K.; Evangelista, L.R. [Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020 - 900 Maringá –PR (Brazil); Zola, R.S., E-mail: rzola@utfpr.edu.br [Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020 - 900 Maringá –PR (Brazil); Universidade Tecnologica Federal do Paraná, Rua Marcilio Dias 635, 86812-460 Apucarana, Paraná (Brazil)

    2014-07-15

    An analytical expression for the relaxation time of a nematic liquid crystal is obtained for the first time by considering the influence of surface viscosity, anchoring energy strength and cell gap, validated numerically by using the so-called relaxation method. This general equation for the molecular response time (τ{sub 0}) was derived for a vertical aligned cell and by solving an eigenvalue equation coming from the usual balance of torque equation in the Derzhanskii and Petrov formulation, recovering the usual equations in the appropriate limit. The results show that τ∼d{sup b}, where b=2 is observed only for strongly anchored cells, while for moderate to weak anchored cells, the exponent lies between 1 and 2, depending on both, surface viscosity and anchoring strength. We found that the surface viscosity is important when calculating the response time, specially for thin cells, critical for liquid crystal devices. The surface viscosity’s effect on the optical response time with pretilt is also explored. Our results bring new insights about the role of surface viscosity and its effects in applied physics. - Highlights: • The relaxation of nematic liquid crystals is calculated by taking the surface viscosity into account. • An analytical expression for the relaxation time depending on surface viscosity, anchoring strength and cell gap is obtained. • The results are numerically verified. • Surface viscosity is crucial for thin and weak anchored cells. • The effect on optical time and pretilt angle is also studied.

  2. Automatic analysis of image of surface structure of cell wall-deficient EVC.

    Science.gov (United States)

    Li, S; Hu, K; Cai, N; Su, W; Xiong, H; Lou, Z; Lin, T; Hu, Y

    2001-01-01

    Some computer applications for cell characterization in medicine and biology, such as analysis of surface structure of cell wall-deficient EVC (El Tor Vibrio of Cholera), operate with cell samples taken from very small areas of interest. In order to perform texture characterization in such an application, only a few texture operators can be employed: the operators should be insensitive to noise and image distortion and be reliable in order to estimate texture quality from images. Therefore, we introduce wavelet theory and mathematical morphology to analyse the cellular surface micro-area image obtained by SEM (Scanning Electron Microscope). In order to describe the quality of surface structure of cell wall-deficient EVC, we propose a fully automatic computerized method. The image analysis process is carried out in two steps. In the first, we decompose the given image by dyadic wavelet transform and form an image approximation with higher resolution, by doing so, we perform edge detection of given images efficiently. In the second, we introduce many operations of mathematical morphology to obtain morphological quantitative parameters of surface structure of cell wall-deficient EVC. The obtained results prove that the method can eliminate noise, detect the edge and extract the feature parameters validly. In this work, we have built automatic analytic software named "EVC.CELL".

  3. Potential Role of Induced Pluripotent Stem Cells (IPSCs for Cell-Based Therapy of the Ocular Surface

    Directory of Open Access Journals (Sweden)

    Ricardo P. Casaroli-Marano

    2015-02-01

    Full Text Available The integrity and normal function of the corneal epithelium are crucial 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—cultured limbal epithelial transplantation (CLET and cultured oral mucosal epithelial transplantation (COMET—present very encouraging clinical results for treating limbal stem cell deficiency (LSCD and restoring vision. Another emerging therapeutic approach consists of obtaining and implementing human progenitor cells of different origins in association with tissue engineering methods. The development of cell-based therapies using stem cells, such as human adult mesenchymal or induced pluripotent stem cells (IPSCs, represent a significant breakthrough in the treatment of certain eye diseases, offering a more rational, less invasive, and better physiological treatment option in regenerative medicine for the ocular surface. This review will focus on the main concepts of cell-based therapies for the ocular surface and the future use of IPSCs to treat LSCD.

  4. Cone Penetrometer Load Cell Temperature and Radiation Testing Results

    Energy Technology Data Exchange (ETDEWEB)

    Follett, Jordan R.

    2013-08-28

    This report summarizes testing activities performed at the Pacific Northwest National Laboratory to verify the cone penetrometer load cell can withstand the tank conditions present in 241-AN-101 and 241-AN-106. The tests demonstrated the load cell device will operate under the elevated temperature and radiation levels expected to be encountered during tank farm deployment of the device.

  5. Roles for glycosylation of cell surface receptors involved in cellular immune recognition.

    Science.gov (United States)

    Rudd, P M; Wormald, M R; Stanfield, R L; Huang, M; Mattsson, N; Speir, J A; DiGennaro, J A; Fetrow, J S; Dwek, R A; Wilson, I A

    1999-10-22

    The majority of cell surface receptors involved in antigen recognition by T cells and in the orchestration of the subsequent cell signalling events are glycoproteins. The length of a typical N-linked sugar is comparable with that of an immunoglobulin domain (30 A). Thus, by virtue of their size alone, oligosaccharides may be expected to play a significant role in the functions and properties of the cell surface proteins to which they are attached. A databank of oligosaccharide structures has been constructed from NMR and crystallographic data to aid in the interpretation of crystal structures of glycoproteins. As unambiguous electron density can usually only be assigned to the glycan cores, the remainder of the sugar is then modelled into the crystal lattice by superimposing the appropriate oligosaccharide from the database. This approach provides insights into the roles that glycosylation might play in cell surface receptors, by providing models that delineate potential close packing interactions on the cell surface. It has been proposed that the specific recognition of antigen by T cells results in the formation of an immunological synapse between the T cell and the antigen-presenting cell. The cell adhesion glycoproteins, such as CD2 and CD48, help to form a cell junction, providing a molecular spacer between opposing cells. The oligosaccharides located on the membrane proximal domains of CD2 and CD48 provide a scaffold to orient the binding faces, which leads to increased affinity. In the next step, recruitment of the peptide major histocompatibility complex (pMHC) by the T-cell receptors (TCRs) requires mobility on the membrane surface. The TCR sugars are located such that they could prevent non-specific aggregation. Importantly, the sugars limit the possible geometry and spacing of TCR/MHC clusters which precede cell signalling. We postulate that, in the final stage, the sugars could play a general role in controlling the assembly and stabilisation of the

  6. Detecting Bacterial Surface Organelles on Single Cells Using Optical Tweezers.

    Science.gov (United States)

    Zakrisson, Johan; Singh, Bhupender; Svenmarker, Pontus; Wiklund, Krister; Zhang, Hanqing; Hakobyan, Shoghik; Ramstedt, Madeleine; Andersson, Magnus

    2016-05-10

    Bacterial cells display a diverse array of surface organelles that are important for a range of processes such as intercellular communication, motility and adhesion leading to biofilm formation, infections, and bacterial spread. More specifically, attachment to host cells by Gram-negative bacteria are mediated by adhesion pili, which are nanometers wide and micrometers long fibrous organelles. Since these pili are significantly thinner than the wavelength of visible light, they cannot be detected using standard light microscopy techniques. At present, there is no fast and simple method available to investigate if a single cell expresses pili while keeping the cell alive for further studies. In this study, we present a method to determine the presence of pili on a single bacterium. The protocol involves imaging the bacterium to measure its size, followed by predicting the fluid drag based on its size using an analytical model, and thereafter oscillating the sample while a single bacterium is trapped by an optical tweezer to measure its effective fluid drag. Comparison between the predicted and the measured fluid drag thereby indicate the presence of pili. Herein, we verify the method using polymer coated silica microspheres and Escherichia coli bacteria expressing adhesion pili. Our protocol can in real time and within seconds assist single cell studies by distinguishing between piliated and nonpiliated bacteria. PMID:27088225

  7. A CLINICAL STUDY OF LIMBAL STEM CELL TRANSPLANTATION IN VARIOUS OCULAR SURFACE DISORDERS

    Directory of Open Access Journals (Sweden)

    Rashmi

    2015-10-01

    Full Text Available AIMS: The purpose of this study is to evaluate the various causes of limbal stem cell deficiency, to assess signs and symptoms in ocular surface disorder and improvement following stem cell transplantation, to carry out limbal stem cell transplantation in various ocular surface disorders and to assess various intraoperative and postoperative complications following stem cell transplantation. METHODS: This study included 40 cases of ocular surface disorders treated with limbal autograft transplantation. Patients were recorded in a predesigned proforma, including the detailed history and complete ophthalmological examination. All cases of ocular surface disorders were treated with conjunctivo-limbal autograft transplantation under peribulbar and facial anaesthesia. RESULT: Maximum number of patients belong to age group 30-40 years. Males were more commonly affected by ocular surface disorders than females. (1.8:1. various causes of limbal stem cell deficiency were reviewed. The most common etiology associated with limbal stem cell deficiency was pterygia (60% followed by vascularised leucomatous corneal opacity (20%, chemical burns (15% and epitheliopathy (5%. Most common symptoms reported by patients were redness (100%, foreign body sensation (90%, watering (85% and photophobia (50%. Most common signs found were conjunctival congestion (90%, corneal vascularization (70%, conjunctivalisation (70% and epithelial defects (30%. 72.5% of patients reported increased ocular comfort. Postoperative incidence of redness was reduced from 90% to 20%, watering from 85% to 15% and photophobia from 50% to 25%. Improvement in signs was noted as decrease in conjunctival congestion from 90% to 22.2%, vascularisation from 70% to 35%, conjunctivalisation from 70% to 21.5% and epithelial defects from 30% to 16.6%. CONCLUSIONS: Use of autologous limbal transplantation with corneal and conjunctival tissue as a vehicle was useful for ocular surface reconstruction in

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Bacterial whole-cell biocatalysts by surface display of enzymes: toward industrial application.

    Science.gov (United States)

    Schüürmann, Jan; Quehl, Paul; Festel, Gunter; Jose, Joachim

    2014-10-01

    Despite the first report on the bacterial display of a recombinant peptide appeared almost 30 years ago, industrial application of cells with surface-displayed enzymes is still limited. To display an enzyme on the surface of a living cell bears several advantages. First of all, neither the substrate nor the product of the enzymatic reaction needs to cross a membrane barrier. Second, the enzyme being linked to the cell can be separated from the reaction mixture and hence the product by simple centrifugation. Transfer to a new substrate preparation results in multiple cycles of enzymatic conversion. Finally, the anchoring in a matrix, in this case, the cell envelope stabilizes the enzyme and makes it less accessible to proteolytic degradation and material adsorption resulting in continuous higher activities. These advantages in common need to balance some disadvantages before this application can be taken into account for industrial processes, e.g., the exclusion of the enzyme from the cellular metabolome and hence from redox factors or other co-factors that need to be supplied. Therefore, this digest describes the different systems in Gram-positive and Gram-negative bacteria that have been used for the surface display of enzymes so far and focuses on examples among these which are suitable for industrial purposes or for the production of valuable resources, not least in order to encourage a broader application of whole-cell biocatalysts with surface-displayed enzymes.

  10. "Race for the Surface": Eukaryotic Cells Can Win.

    Science.gov (United States)

    Pham, Vy T H; Truong, Vi Khanh; Orlowska, Anna; Ghanaati, Shahram; Barbeck, Mike; Booms, Patrick; Fulcher, Alex J; Bhadra, Chris M; Buividas, Ričardas; Baulin, Vladimir; Kirkpatrick, C James; Doran, Pauline; Mainwaring, David E; Juodkazis, Saulius; Crawford, Russell J; Ivanova, Elena P

    2016-08-31

    With an aging population and the consequent increasing use of medical implants, managing the possible infections arising from implant surgery remains a global challenge. Here, we demonstrate for the first time that a precise nanotopology provides an effective intervention in bacterial cocolonization enabling the proliferation of eukaryotic cells on a substratum surface, preinfected by both live Gram-negative, Pseudomonas aeruginosa, and Gram-positive, Staphylococcus aureus, pathogenic bacteria. The topology of the model black silicon (bSi) substratum not only favors the proliferation of eukaryotic cells but is biocompatible, not triggering an inflammatory response in the host. The attachment behavior and development of filopodia when COS-7 fibroblast cells are placed in contact with the bSi surface are demonstrated in the dynamic study, which is based on the use of real-time sequential confocal imaging. Bactericidal nanotopology may enhance the prospect for further development of inherently responsive antibacterial nanomaterials for bionic applications such as prosthetics and implants. PMID:27494044

  11. Anomalous wave as a result of the collision of two wave groups on sea surface

    CERN Document Server

    Ruban, V P

    2016-01-01

    The numerical simulation of the nonlinear dynamics of the sea surface has shown that the collision of two groups of relatively low waves with close but noncollinear wave vectors (two or three waves in each group with a steepness of about 0.2) can result in the appearance of an individual anomalous wave whose height is noticeably larger than that in the linear theory. Since such collisions quite often occur on the ocean surface, this scenario of the formation of rogue waves is apparently most typical under natural conditions.

  12. Role of a cell surface-associated protein in adherence and dental caries.

    OpenAIRE

    Bowen, W. H.; Schilling, K.; Giertsen, E; Pearson, S.; Lee, S. F.; Bleiweis, A; Beeman, D

    1991-01-01

    Insertional inactivation of the Streptococcus mutans spaP gene was used to construct an isogenic mutant (834) of strain NG8 (serotype c) which lacked the major cell surface-associated protein referred to as P1 (15). Results of several studies suggest that P1 is involved in the adherence of S. mutans to saliva-coated apatite surfaces. With an in vitro model system of hydroxyapatite (HA) beads coated with parotid saliva (PS) and additional HA surfaces coated with PS and in situ-formed glucan, i...

  13. Simulation of the Mars Surface Solar Spectra for Optimized Performance of Triple-Junction Solar Cells

    Science.gov (United States)

    Edmondson, Kenneth M.; Joslin, David E.; Fetzer, Chris M.; King, RIchard R.; Karam, Nasser H.; Mardesich, Nick; Stella, Paul M.; Rapp, Donald; Mueller, Robert

    2007-01-01

    The unparalleled success of the Mars Exploration Rovers (MER) powered by GaInP/GaAs/Ge triple-junction solar cells has demonstrated a lifetime for the rovers that exceeded the baseline mission duration by more than a factor of five. This provides confidence in future longer-term solar powered missions on the surface of Mars. However, the solar cells used on the rovers are not optimized for the Mars surface solar spectrum, which is attenuated at shorter wavelengths due to scattering by the dusty atmosphere. The difference between the Mars surface spectrum and the AM0 spectrum increases with solar zenith angle and optical depth. The recent results of a program between JPL and Spectrolab to optimize GaInP/GaAs/Ge solar cells for Mars are presented. Initial characterization focuses on the solar spectrum at 60-degrees zenith angle at an optical depth of 0.5. The 60-degree spectrum is reduced to 1/6 of the AM0 intensity and is further reduced in the blue portion of the spectrum. JPL has modeled the Mars surface solar spectra, modified an X-25 solar simulator, and completed testing of Mars-optimized solar cells previously developed by Spectrolab with the modified X-25 solar simulator. Spectrolab has focused on the optimization of the higher efficiency Ultra Triple-Junction (UTJ) solar cell for Mars. The attenuated blue portion of the spectrum requires the modification of the top sub-cell in the GaInP/GaAs/Ge solar cell for improved current balancing in the triple-junction cell. Initial characterization confirms the predicted increase in power and current matched operation for the Mars surface 60-degree zenith angle solar spectrum.

  14. Lumped series resistance of solar cells as a result of distributed sheet resistance

    Science.gov (United States)

    Sokolić, Saša; Križaj, Dejan; Amon, Slavko

    1993-04-01

    An analysis of solar cell distributed sheet resistance is performed by solving the nonlinear Poisson equation for the surface potential. Two different approaches to lumped series resistance are discussed: equivalent series resistance RSeq obtained from the cell's equivalent circuit that satisfies the actual current of the cell (all other parameters in the equivalent circuit except the series resistance are kept constant) and Joule series resistance RSJ obtained from the Joule losses in the emitter of the cell. It is observed that the I( U) characteristic obtained from the equivalent circuit that includes RSJ generally disagrees with the actual I( U) characteristic of the solar cell. An additional series resistance RSadd should be introduced in series with RSJ. Series resistances RSJ, Sadd and RSeq are analyzed numerically in one and two dimensions for different conditions of terminal voltage, illumination and weighted sheet resistance Rshb2, where b is related to the geometry of the analyzed cell. Following the derivations and the results of the numerical analysis it can be concluded that wherever RSJ varies as a function of terminal voltage, RSadd should be taken into consideration.

  15. Cell surface glycopeptides from human intestinal epithelial cell lines derived from normal colon and colon adenocarcinomas

    International Nuclear Information System (INIS)

    The cell surface glycopeptides from an epithelial cell line (CCL 239) derived from normal human colon were compared with those from three cell lines (HCT-8R, HCT-15, and CaCo-2) derived independently from human colonic adenocarcinomas. Cells were incubated with D-[2-3H]mannose or L-[5,6-3H]fucose for 24 h and treated with trypsin to release cell surface components which were then digested exhaustively with Pronase and fractionated on Bio-Gel P-6 before and after treatment with endo-beta-N-acetylglucosaminidase H. The most noticeable difference between the labeled glycopeptides from the tumor and CCL 239 cells was the presence in the former of an endo-beta-N-acetylglucosaminidase H-resistant high molecular weight glycopeptide fraction which was eluted in the void volume of Bio-Gel P-6. This fraction was obtained with both labeled mannose and fucose as precursors. However, acid hydrolysis of this fraction obtained after incubation with [2-3H]mannose revealed that as much as 60-90% of the radioactivity was recovered as fucose. Analysis of the total glycopeptides (cell surface and cell pellet) obtained after incubation with [2-3H]mannose showed that from 40-45% of the radioactivity in the tumor cells and less than 10% of the radioactivity in the CCL 239 cells was recovered as fucose. After incubation of the HCT-8R cells with D-[1,6-3H]glucosamine and L-[1-14C]fucose, strong acid hydrolysis of the labeled glycopeptide fraction excluded from Bio-Gel P-6 produced 3H-labeled N-acetylglucosamine and N-acetylgalactosamine

  16. Evaluation of Relative Yeast Cell Surface Hydrophobicity Measured by Flow Cytometry

    Directory of Open Access Journals (Sweden)

    Lisa Colling

    2005-01-01

    Full Text Available Objective: To develop an efficient method for evaluating cell surface hydrophobicity and to apply the method to demonstrate the effects of fungal growth conditions on cell surface properties.

  17. Olopatadine Inhibits Exocytosis in Rat Peritoneal Mast Cells by Counteracting Membrane Surface Deformation

    Directory of Open Access Journals (Sweden)

    Asuka Baba

    2015-01-01

    Full Text Available Backgroud/Aims: Besides its anti-allergic properties as a histamine receptor antagonist, olopatadine stabilizes mast cells by inhibiting the release of chemokines. Since olopatadine bears amphiphilic features and is preferentially partitioned into the lipid bilayers of the plasma membrane, it would induce some morphological changes in mast cells and thus affect the process of exocytosis. Methods: Employing the standard patch-clamp whole-cell recording technique, we examined the effects of olopatadine and other anti-allergic drugs on the membrane capacitance (Cm in rat peritoneal mast cells during exocytosis. Using confocal imaging of a water-soluble fluorescent dye, lucifer yellow, we also examined their effects on the deformation of the plasma membrane. Results: Low concentrations of olopatadine (1 or 10 µM did not significantly affect the GTP-γ-S-induced increase in the Cm. However, 100 µM and 1 mM olopatadine almost totally suppressed the increase in the Cm. Additionally, these doses completely washed out the trapping of the dye on the cell surface, indicating that olopatadine counteracted the membrane surface deformation induced by exocytosis. As shown by electron microscopy, olopatadine generated inward membrane bending in mast cells. Conclusion: This study provides electrophysiological evidence for the first time that olopatadine dose-dependently inhibits the process of exocytosis in rat peritoneal mast cells. Such mast cell stabilizing properties of olopatadine may be attributed to its counteracting effects on the plasma membrane deformation in degranulating mast cells.

  18. Targeting pancreatic progenitor cells in human embryonic stem cell differentiation for the identification of novel cell surface markers.

    Science.gov (United States)

    Fishman, Bettina; Segev, Hanna; Kopper, Oded; Nissenbaum, Jonathan; Schulman, Margarita; Benvenisty, Nissim; Itskovitz-Eldor, Joseph; Kitsberg, Danny

    2012-09-01

    New sources of beta cells are needed in order to develop cell therapies for patients with diabetes. An alternative to forced expansion of post-mitotic beta cells is the induction of differentiation of stem-cell derived progenitor cells that have a natural self-expansion capacity into insulin-producing cells. In order to learn more about these progenitor cells at different stages along the differentiation process in which they become progressively more committed to the final beta cell fate, we took the approach of identifying, isolating and characterizing stage specific progenitor cells. We generated human embryonic stem cell (HESC) clones harboring BAC GFP reporter constructs of SOX17, a definitive endoderm marker, and PDX1, a pancreatic marker, and identified subpopulations of GFP expressing cells. Using this approach, we isolated a highly enriched population of pancreatic progenitor cells from hESCs and examined their gene expression with an emphasis on the expression of stage-specific cell surface markers. We were able to identify novel molecules that are involved in the pancreatic differentiation process, as well as stage-specific cell markers that may serve to define (alone or in combination with other markers) a specific pancreatic progenitor cell. These findings may help in optimizing conditions for ultimately generating and isolating beta cells for transplantation therapy.

  19. E-transfer of materials surface engineering e-foresight results

    Directory of Open Access Journals (Sweden)

    A.D. Dobrzańska-Danikiewicz

    2011-12-01

    Full Text Available Purpose: The purpose of the paper is to present an innovative concept of e-transfer of tech¬nology e-foresight results concerning materials surface technology, allowing for the practical industrial implementation of the results of materials science-heuristic research using a state-of-art IT technology.Design/methodology/approach: Technology e-transfer is an innovating concept popularised in industry, especially in SMEs, developed in the course of the previously pursued e-foresight research of modern knowledge concerning the priority innovative materials surface technologies and the forecast directions of their development.Findings: Technology e-transfer embracing e-information, e-advisory and e-learning, is an efficient method of disseminating the results of technology e-foresight of materials surface engineering within industry.Research limitations/implications: If technology e-transfer is used in the Open Access mode, anyone, for free and at the same terms, has access to a database on the priority innovative tech¬nologies of materials surface engineering and the anticipated directions of their development, which has a positive effect on the development of a knowledge- and innovation-based economy.Practical implications: The idea of disseminating the results of e-foresight of materials surface engineering by way of technology e-transfer is especially attractive for small- and medium-sized companies lacking the funds required to perform their own research in this scope.Originality/value: The concept of technology e-transfer represents the Authors’ original contribution into the development of Computer Aided Knowledge Management.

  20. Results of 200 KW fuel cell evaluation programs

    Energy Technology Data Exchange (ETDEWEB)

    Torrey, J.M.; Merten, G.P. [SAIC, San Diego, CA (United States); Binder, M.J. [Army Construction Engineering Research Labs., Champaign, IL (United States)] [and others

    1996-12-31

    Science Applications International Corporation (SAIC) has installed six monitoring systems on ONSI Corporation 200 kW phosphoric acid fuel cells. Three of the systems were installed for the U.S. Army Construction Engineering Research Laboratories (USACERL) which is coordinating the Department of Defense (DoD) fuel cell Demonstration Program and three were installed under a contract with the New York State Energy Research and Development Authority (NYSERDA). Monitoring of the three NYSERDA sites has been completed. Monitoring systems for the DoD fuel cells were installed in August, 1996 and thus no operating data was available at the time of this writing, but will be presented at the Fuel Cell Seminar. This paper will present the monitoring configuration and research approach for each program. Additionally, summary performance data is presented for the completed NYSERDA program.

  1. Immobilized cell technology in beer brewing: Current experience and results

    OpenAIRE

    Leskošek-Čukalov Ida J.; Nedović Viktor A.

    2005-01-01

    Immobilized cell technology (ICT) has been attracting continual attention in the brewing industry over the past 30 years. Some of the reasons are: faster fermentation rates and increased volumetric productivity, compared to those of traditional beer production based on freely suspended cells, as well as the possibility of continuous operation. Nowadays, ICT technology is well established in secondary fermentation and alcohol- free and low-alcohol beer production. In main fermentation, the sit...

  2. Longitudinal microarray analysis of cell surface antigens on peripheral blood mononuclear cells from HIV+ individuals on highly active antiretroviral therapy

    Directory of Open Access Journals (Sweden)

    Wang Bin

    2008-03-01

    Full Text Available Abstract Background The efficacy of highly active antiretroviral therapy (HAART determined by simultaneous monitoring over 100 cell-surface antigens overtime has not been attempted. We used an antibody microarray to analyze changes in the expression of 135 different cell-surface antigens overtime on PBMC from HIV+ patients on HAART. Two groups were chosen, one (n = 6 achieved sustainable response by maintaining below detectable plasma viremia and the other (n = 6 responded intermittently. Blood samples were collected over an average of 3 years and 5–8 time points were selected for microarray assay and statistical analysis. Results Significant trends over time were observed for the expression of 7 cell surface antigens (CD2, CD3epsilon, CD5, CD95, CD36, CD27 and CD28 for combined patient groups. Between groups, expression levels of 10 cell surface antigens (CD11a, CD29, CD38, CD45RO, CD52, CD56, CD57, CD62E, CD64 and CD33 were found to be differential. Expression levels of CD9, CD11a, CD27, CD28 and CD52, CD44, CD49d, CD49e, CD11c strongly correlated with CD4+ and CD8+ T cell counts, respectively. Conclusion Our findings not only detected markers that may have potential prognostic/diagnostic values in evaluating HAART efficacy, but also showed how density of cell surface antigens could be efficiently exploited in an array-like manner in relation to HAART and HIV-infection. The antigens identified in this study should be further investigated by other methods such as flow cytometry for confirmation as biological analysis of these antigens may help further clarify their role during HAART and HIV infection.

  3. Surface roughness effect on the metallic bipolar plates of a proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Highlights: ► Various degrees of roughness are caused by the sandblasting method. ► An improper surface modification depletes the PEMFC performance severely. ► The AC impedance are used to assess the fuel gas transfer effect. ► The Warburg resistance form in the coarse flow channel surface. - Abstract: Proton exchange membrane fuel cells (PEMFCs) is a promising candidate as energy systems. However, the stability and lifetime of cells are still important issues. The effect of surface roughness on metallic bipolar plate is discussed in this paper. Various roughness on the bulk surface are obtained by the sandblasting method. The grain sizes of sand are selected as 50, 100 and 200 μm. The Ac impedance experiment results show that the bipolar plate roughness and carbon paper porosity are well matched when the surface roughness is within 1–2 μm. Superior condition decreases the contact resistance loss in the fuel cell. The high frequency resistance of the coarse surface was larger than that of the substrate by around 5 mΩ. Furthermore, a new arc was formed at the low frequency region. Hence, the unmatch roughness condition of the bipolar plate significantly increases the contact resistance and mass transfer resistance. This paper develops a sequential approach to study an optimum surface roughness by combining the whole performance (I–V) curve and AC impedance result. It benefits us to quantify the contact and mass transfer resistance exists in the PEMFC. The proposed surface treatment improves the surface effect and promotes the implement of potential metallic bipolar plate in near future

  4. Near-surface alloys for hydrogen fuel cell applications

    DEFF Research Database (Denmark)

    Greeley, Jeffrey Philip; Mavrikakis, Manos

    2006-01-01

    Near-surface alloys (NSAs) possess a variety of unusual catalytic properties that could make them useful candidates for improved catalysts in a variety of chemical processes. It is known from previous work, for example, that some NSAs bind hydrogen very weakly while, at the same time, permitting...... facile H-2 activation. These NSAs could, potentially, facilitate highly selective hydrogenation reactions at low temperatures. In the present work, the suitability of NSAs for use as hydrogen fuel cell anodes has been evaluated: the combination of properties, possessed by selected NSAs, of weak binding...

  5. Surface plasmon enhanced cell microscopy with blocked random spatial activation

    Science.gov (United States)

    Son, Taehwang; Oh, Youngjin; Lee, Wonju; Yang, Heejin; Kim, Donghyun

    2016-03-01

    We present surface plasmon enhanced fluorescence microscopy with random spatial sampling using patterned block of silver nanoislands. Rigorous coupled wave analysis was performed to confirm near-field localization on nanoislands. Random nanoislands were fabricated in silver by temperature annealing. By analyzing random near-field distribution, average size of localized fields was found to be on the order of 135 nm. Randomly localized near-fields were used to spatially sample F-actin of J774 cells (mouse macrophage cell-line). Image deconvolution algorithm based on linear imaging theory was established for stochastic estimation of fluorescent molecular distribution. The alignment between near-field distribution and raw image was performed by the patterned block. The achieved resolution is dependent upon factors including the size of localized fields and estimated to be 100-150 nm.

  6. Fusion of the upstream vpu sequences to the env of simian human immunodeficiency virus (SHIVKU-1bMC33) results in the synthesis of two envelope precursor proteins, increased numbers of virus particles associated with the cell surface and is pathogenic for pig-tailed macaques

    International Nuclear Information System (INIS)

    Previous studies have shown that the gene coding for the Vpu protein of the human immunodeficiency virus type 1 (HIV-1) is 5' to the env gene, is in a different reading frame, and overlaps the env by 90 nucleotides. In this study, we examined the processing of the Env protein as well as the maturation and infectivity of a virus (SHIVVpenv) in which a single nucleotide was removed at the vpu-env junction, fusing the first 162 bases of vpu to the env ORF. Pulse-chase analysis revealed that SHIVVpenv-infected cells gave rise to two precursor glycoprotein species (gp160 and gp175). Immune precipitation results also revealed that an anti-Vpu serum could immune precipitate the gp175 precursor, suggesting that the amino-terminal Vpu sequence was fused to the Env protein. Growth curves revealed that the SHIVVpenv-inoculated cultures released approximately three times more p27 into the culture medium than parental SHIVKU-1bMC33. Electron microscopy revealed that while both viruses matured at the cell plasma membrane, significantly higher quantities of virus particles were cell associated on SHIVVpenv-infected cells compared to cultures inoculated with parental SHIVKU-1bMC33. Furthermore, virus was observed maturing into intracellular vesicles of SHIVVpenv-infected cells. To assess the pathogenicity of SHIVVpenv, three pig-tailed macaques were inoculated with the SHIVVpenv and monitored for 6 months for CD4+ T cell levels, viral loads, and the stability of the deletion at the vpu-env junction. Our results indicated that SHIVVpenv caused a severe CD4+ T cell loss in all three macaques within weeks of inoculation. Sequence analysis of the vpu gene analyzed from sequential PBMC samples derived from macaques revealed that this mutation was stable during the period of rapid CD4+ T cell loss. Sequence analysis showed that with increasing time of infection, the one base pair deletion was repaired in all three macaques inoculated with SHIVVpenv with the reversion occurring at 10

  7. Correlation between the Sensitivity to TRAIL and the Expression Level of DR5 on the Surface of Tumor Cells

    Institute of Scientific and Technical Information of China (English)

    Yuanfang Ma; Jun Zhang; Yueping Zhao

    2005-01-01

    OBJECTIVE To investigate the correlation between the sensitivity to the tumor necrosis factor- related apoptosis inducing ligand (TRAIL) and the level of expression of the death receptor 5 (DR5) on the surface of tumor cells.METHODS Anti-DR5 mAbs were used to directly detect the level of expression of DR5 on the surface of tumor cells. Using a TRAIL apoptosis kit and flow cytometry, the sensitivity of the tumor cells to TRAIL-induced apoptosis was determined and the correlation between DR5 expression and sensitivity to TRAIL analyzed.RESULTS The expression level of DR5 on the surface of different tumor cells was as follows: 97.9% in U937 cells, 95.1% in Jurkat cells, 93.8% in SW480 cells, 86.2% in HCT116 cells, 64.2% in HL-60 cells, 46.6% in Hela cells and 13.1% in K562 cells. The TRAIL-induced apoptotic rate was 72.6% in U937 cells, 85.2% in Jurkat cells, 78.6% in SW480 cells, 70.2% in HCT116 cells,60.1% in HL-60 cells, 45.4% in Hela cells and 12.3% in K562 cells. Statistical analysis showed there was a significant positive correlation (r=0.997, P<0.001) between DR5 expression and sensitivity to TRAIL.CONCLUSION The sensitivity of tumor cells to TRAIL is related to the level of expression of DR5 on the surface of tumor cells. These results confirm the importance of DR5 expression for induction of apoptosis by TRAIL.

  8. The anticancer activity of lytic peptides is inhibited by heparan sulfate on the surface of the tumor cells

    Directory of Open Access Journals (Sweden)

    Rekdal Øystein

    2009-06-01

    Full Text Available Abstract Background Cationic antimicrobial peptides (CAPs with antitumor activity constitute a promising group of novel anticancer agents. These peptides induce lysis of cancer cells through interactions with the plasma membrane. It is not known which cancer cell membrane components influence their susceptibility to CAPs. We have previously shown that CAPs interact with the two glycosaminoglycans (GAGs, heparan sulfate (HS and chondroitin sulfate (CS, which are present on the surface of most cells. The purpose of this study was to investigate the role of the two GAGs in the cytotoxic activity of CAPs. Methods Various cell lines, expressing different levels of cell surface GAGs, were exposed to bovine lactoferricin (LfcinB and the designer peptide, KW5. The cytotoxic effect of the peptides was investigated by use of the colorimetric MTT viability assay. The cytotoxic effect on wild type CHO cells, expressing normal amounts of GAGs on the cell surface, and the mutant pgsA-745, that has no expression of GAGs on the cell surface, was also investigated. Results We show that cells not expressing HS were more susceptible to CAPs than cells expressing HS at the cell surface. Further, exogenously added heparin inhibited the cytotoxic effect of the peptides. Chondroitin sulfate had no effect on the cytotoxic activity of KW5 and only minor effects on LfcinB cytotoxicity. Conclusion Our results show for the first time that negatively charged molecules at the surface of cancer cells inhibit the cytotoxic activity of CAPs. Our results indicate that HS at the surface of cancer cells sequesters CAPs away from the phospholipid bilayer and thereby impede their ability to induce cytolysis.

  9. Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

    OpenAIRE

    Wei Luo; Abigail Pulsipher; Debjit Dutta; Lamb, Brian M.; Yousaf, Muhammad N.

    2014-01-01

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture ...

  10. Revealing the fate of cell surface human P-glycoprotein (ABCB1): The lysosomal degradation pathway.

    Science.gov (United States)

    Katayama, Kazuhiro; Kapoor, Khyati; Ohnuma, Shinobu; Patel, Atish; Swaim, William; Ambudkar, Indu S; Ambudkar, Suresh V

    2015-10-01

    P-glycoprotein (P-gp) transports a variety of chemically dissimilar amphipathic compounds including anticancer drugs. Although mechanisms of P-gp drug transport are widely studied, the pathways involving its internalization are poorly understood. The present study is aimed at elucidating the pathways involved in degradation of cell surface P-gp. The fate of P-gp at the cell surface was determined by biotinylating cell surface proteins followed by flow cytometry and Western blotting. Our data shows that the half-life of endogenously expressed P-gp is 26.7±1.1 h in human colorectal cancer HCT-15 cells. Treatment of cells with Bafilomycin A1 (BafA1) a vacuolar H+ ATPase inhibitor increased the half-life of P-gp at the cell surface to 36.1±0.5 h. Interestingly, treatment with the proteasomal inhibitors MG132, MG115 or lactacystin alone did not alter the half-life of the protein. When cells were treated with both lysosomal and proteasomal inhibitors (BafA1 and MG132), the half-life was further prolonged to 39-50 h. Functional assays done with rhodamine 123 or calcein-AM, fluorescent substrates of P-gp, indicated that the transport function of P-gp was not affected by either biotinylation or treatment with BafA1 or proteasomal inhibitors. Immunofluorescence studies done with the antibody against lysosomal marker LAMP1 and the P-gp-specific antibody UIC2 in permeabilized cells indicated that intracellular P-gp is primarily localized in the lysosomal compartment. Our results suggest that the lysosomal degradation system could be targeted to increase the sensitivity of P-gp- expressing cancer cells towards chemotherapeutic drugs.

  11. Surface modification of liposomes with rhodamine-123-conjugated polymer results in enhanced mitochondrial targeting

    Science.gov (United States)

    Biswas, Swati; Dodwadkar, Namita S.; Sawant, Rupa R.; Koshkaryev, Alexander; Torchilin, Vladimir P.

    2012-01-01

    A novel mitochondrial-targeted liposomal drug-delivery system was prepared by modification of the liposomal surface with a newly synthesized polymer, rhodamine-123 (Rh123)-PEG-DOPE inserted into the liposomal lipid bilayer. This novel polymer was synthesized by conjugating the mitochondriotropic dye Rh123, with the amphiphilic polyethylene glycol–phosphatidylethanolamine (PEG-PE) conjugate. The modified liposomes showed better uptake by cells (HeLa, B16F10) estimated by fluorescence microscopy and FACS analysis. The co-localization study with stained mitochondria as well as with the isolation of mitochondria of the cultured cells after their treatment with Rh123 liposomes showed a high degree of accumulation of the modified liposomes in the mitochondria. We also prepared mitochondrial-targeted and nontargeted paclitaxel (PCL)-loaded liposomes. Mitochondrial-targeted PCL-loaded liposomes demonstrated enhanced cytotoxicity toward cancer cells compared with nontargeted drug-loaded liposomes or free PCL. Thus, Rh123-modified liposomes target mitochondria efficiently and can facilitate the delivery of a therapeutic payload to mitochondria. PMID:21348804

  12. Surface Tension and Viscosity Measurements in Microgravity: Some Results and Fluid Flow Observations during MSL-1

    Science.gov (United States)

    Hyer, Robert W.; Trapaga, G.; Flemings, M. C.

    1999-01-01

    The viscosity of a liquid metal was successfully measured for the first time by a containerless method, the oscillating drop technique. This method also provides a means to obtain a precise, non-contact measurement of the surface tension of the droplet. This technique involves exciting the surface of the molten sample and then measuring the resulting oscillations; the natural frequency of the oscillating sample is determined by its surface tension, and the damping of the oscillations by the viscosity. These measurements were performed in TEMPUS, a microgravity electromagnetic levitator (EML), on the Space Shuttle as a part of the First Microgravity Science Laboratory (MSL-1), which flew in April and July 1997 (STS-83 and STS-94). Some results of the surface tension and viscosity measurements are presented for Pd82Si18. Some observations of the fluid dynamic characteristics (dominant flow patterns, turbulent transition, cavitation, etc.) of levitated droplets are presented and discussed together with magnetohydrodynamic calculations, which were performed to justify these findings.

  13. Surface-engineered substrates for improved human pluripotent stem cell culture under fully defined conditions

    OpenAIRE

    Saha, Krishanu; Mei, Ying; Reisterer, Colin M.; Pyzocha, Neena Kenton; Yang, Jing; Muffat, Julien; Davies, Martyn C.; Alexander, Morgan R.; Langer, Robert; Anderson, Daniel G.; Jaenisch, Rudolf

    2011-01-01

    The current gold standard for the culture of human pluripotent stem cells requires the use of a feeder layer of cells. Here, we develop a spatially defined culture system based on UV/ozone radiation modification of typical cell culture plastics to define a favorable surface environment for human pluripotent stem cell culture. Chemical and geometrical optimization of the surfaces enables control of early cell aggregation from fully dissociated cells, as predicted from a numerical model of cell...

  14. Enhanced cell-material interactions through the biofunctionalization of polymeric surfaces with engineered peptides.

    Science.gov (United States)

    Punet, Xavier; Mauchauffé, Rodolphe; Giannotti, Marina I; Rodríguez-Cabello, José C; Sanz, Fausto; Engel, Elisabeth; Mateos-Timoneda, Miguel A; Planell, Josep A

    2013-08-12

    Research on surface modification of polymeric materials to guide the cellular activity in biomaterials designed for tissue engineering applications has mostly focused on the use of natural extracellular matrix (ECM) proteins and short peptides, such as RGD. However, the use of engineered proteins can gather the advantages of these strategies and avoid the main drawbacks. In this study, recombinant engineered proteins called elastin-like recombinamers (ELRs) have been used to functionalize poly(lactic) acid (PLA) model surfaces. The structure of the ELRs has been designed to include the integrin ligand RGDS and the cross-linking module VPGKG. Surface functionalization has been characterized and optimized by means of ELISA and atomic force microscopy (AFM). The results suggest that ELR functionalization creates a nonfouling canvas able to restrict unspecific adsorption of proteins. Moreover, AFM analysis reveals the conformation and disposition of ELRs on the surface. Biological performance of PLA surfaces functionalized with ELRs has been studied and compared with the use of short peptides. Cell response has been assessed for different functionalization conditions in the presence and absence of the bovine serum albumin (BSA) protein, which could interfere with the surface-cell interaction by adsorbing on the interface. Studies have shown that ELRs are able to elicit higher rates of cell attachment, stronger cell anchorages and faster levels of proliferation than peptides. This work has demonstrated that the use of engineered proteins is a more efficient strategy to guide the cellular activity than the use of short peptides, because they not only allow for better cell attachment and proliferation, but also can provide more complex properties such as the creation of nonfouling surfaces. PMID:23805782

  15. Annexin A8 controls leukocyte recruitment to activated endothelial cells via cell surface delivery of CD63

    Science.gov (United States)

    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.

  16. Changes in cell morphology of Listeria monocytogenesnes and Shewanella putrefaciens resulting from the action of protamine

    DEFF Research Database (Denmark)

    Johansen, Charlotte; Gill, T.; Gram, Lone

    1996-01-01

    Protamine, which is an antibacterial basic peptide, was shown to alter the cell morphology of Listeria monocytogenes and Shewanella putrefaciens. Atomic force microscopy revealed that protamine smoothed the surface of cells, formed holes in the cell envelope, and caused fusion of S. putrefaciens...

  17. Amphipaths Differentially Modulate Membrane Surface Deformation in Rat Peritoneal Mast Cells During Exocytosis

    Directory of Open Access Journals (Sweden)

    Itsuro Kazama

    2013-04-01

    Full Text Available Background/Aims: Salicylate and chlorpromazine exert differential effects on the chemokine release from mast cells. Since these drugs are amphiphilic and preferentially partitioned into the lipid bilayers of the plasma membranes, they would induce some morphological changes in mast cells and thus affect the process of exocytosis. Methods: Employing the standard patch-clamp whole-cell recording technique, we examined the effects of salicylate and chlorpromazine on the membrane capacitance (Cm during exocytosis in rat peritoneal mast cells. Using confocal imaging of a water-soluble fluorescent dye, lucifer yellow, we also examined their effects on plasma membrane deformation of the cells. Results: Salicylate dramatically accelerated the GTP-γ-S-induced increase in the Cm immediately after its application, whereas chlorpromazine significantly suppressed the increase. Treatment with salicylate increased the trapping of the dye on the cell surface, while treatment with chlorpromazine completely washed it out, indicating that both drugs induced membrane surface deformation in mast cells. Conclusion: This study demonstrated for the first time that membrane amphipaths, such as salicylate and chlorpromazine, may oppositely modulate the process of exocytosis in mast cells, as detected by the changes in the Cm. The plasma membrane deformation induced by the drugs was thought to be responsible for their differential effects.

  18. TEST RESULTS FOR FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS

    Science.gov (United States)

    EPA, in conjunction with ONSI Corp., embarked on a project to define, design, test, and assess a fuel cell energy recovery system for application at anaerobic digester waste water (sewage) treatment plants. Anaerobic digester gas (ADG) is produced at these plants during the proce...

  19. Stem cells show promising results for lymphoedema treatment

    DEFF Research Database (Denmark)

    Toyserkani, Navid Mohamadpour; Quaade, Marlene Louise; Sheikh, Søren Paludan;

    2015-01-01

    Abstract Lymphoedema is a debilitating condition, manifesting in excess lymphatic fluid and swelling of subcutaneous tissues. Lymphoedema is as of yet still an incurable condition and current treatment modalities are not satisfactory. The capacity of mesenchymal stem cells to promote angiogenesis...

  20. Favourable results of Mohs micrographic surgery for basal cell carcinoma

    DEFF Research Database (Denmark)

    Gniadecki, Robert; Glud, Martin; Mortensen, Kia;

    2015-01-01

    INTRODUCTION: Basal cell carcinoma (BCC) is the most common malignant neoplasm with an annual incidence approaching 200/100,000 person-years. Mohs micrographic surgery (MMS) is widely used in North America and in Europe for treatment of BCC. This technique ensures radical tumour removal, sparing of...

  1. Potential dose distributions at proposed surface radioactvity clearance levels resulting from occupational scenarios.

    Energy Technology Data Exchange (ETDEWEB)

    Kamboj, S.; Yu, C.; Rabovsky, J. (Environmental Science Division); (USDOE)

    2011-08-02

    The purpose of this report is to evaluate the potential dose distribution resulting from surface radioactivity, using occupational radiation exposure scenarios. The surface radioactivity clearance values considered in this analysis may ultimately replace those currently specified in the U.S. Department of Energy (DOE) requirements and guidance for radiological protection of workers, the public and the environment. The surface contamination values apply to radioactive contamination deposited on a surface (i.e., not incorporated into the interior of the material). For these calculations, the dose coefficients for intake of radionuclides were taken from ICRP Publication 68 (ICRP 1994), and external exposure dose coefficients were taken from the compact disc (CD) that accompanied Federal Guidance Report (FGR) 13 (Eckerman et al. 1999). The ICRP Publication 68 dose coefficients were based on ICRP Publication 60 (ICRP 1990) and were used specifically for worker dose calculations. The calculated dose in this analysis is the 'effective dose' (ED), rather than the 'effective dose equivalent' (EDE).

  2. Distribution of Prestin on Outer Hair Cell Basolateral Surface

    Institute of Scientific and Technical Information of China (English)

    YU Ning; ZHAI Suo-qiang; YANG Shi-ming; HAN Dong-yi; ZHAO Hong-bo

    2008-01-01

    Prestin has been identified as a motor protein responsible for outer hair cell (OHC) electromotility and is expressed on the OHC surface. Previous studies revealed that OHC eleetromotility and its associated nonlinear capacitance were mainly located at the OHC lateral wall and absent at the apical cutieular plate and the basal nucleus region. Immunofluorescent staining for prestin also failed to demonstrate prestin expression at the OHC basal ends in whole-mount preparation of the organ of Corti. However, there lacks a definitive demonstration of the pattern of prestin distribution. The OHC lateral wall has a trilaminate organization and is composed of the plasma membrane, cortical lattice, and subsurface cisternae. In this study, the location of prestin proteins in dissociated OHCs was examined using immunofluorescent staining and confocal microscopy. We found that prestin was uniformly expressed on the basolateral surface, including the basal pole. No staining was seen on the cuticular plate and stereocilia. When co-stained with a membrane marker di-8-ANEPPS, prestin-labeling was found to be in the outer layer of the OHC lateral wall. After separating the plasma membrane from the underlying subsurface eisternae using a hypotonic extracellular solution, prestin-labeling was found to be in the plasma membrane, not the subsurface cisternae. The data show that prestin is expressed in the plasma membrane on the entire OHC basolateral surface.

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

    Science.gov (United States)

    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

  4. Surface Analyses and Immune Reactivities of Major Cell Wall-Associated Proteins of Group A Streptococcus

    OpenAIRE

    Cole, Jason N; Ramirez, Ruben D.; Currie, Bart J.; Cordwell, Stuart J.; Djordjevic, Steven P.; Mark J Walker

    2005-01-01

    A proteomic analysis was undertaken to identify cell wall-associated proteins of Streptococcus pyogenes. Seventy-four distinct cell wall-associated proteins were identified, 66 of which were novel. Thirty-three proteins were immunoreactive with pooled S. pyogenes-reactive human antisera. Biotinylation of the GAS cell surface identified 23 cell wall-associated proteins that are surface exposed.

  5. In vitro studies on the influence of surface modification of Ni-Ti alloy on human bone cells.

    Science.gov (United States)

    Chrzanowski, Wojciech; Neel, Ensanya A Abou; Armitage, David A; Zhao, Xin; Knowles, Jonathan C; Salih, Vehid

    2010-06-15

    The in vitro cell behavior on Nitinol after different surface treatments was investigated. As references samples, commercially pure titanium (cpTi) and bioactive titanium were used. The surface treatments influenced the topography, surface energy, crystallographic structure, ion release, chemistry, and ability to form apatite layer from simulated body fluids. Regardless of the surface treatment, the bioactivity study showed that the kinetics of apatite film formation was similar for all tested samples. No clear indication of the surface characteristics influence on the ability for calcium-phosphate precipitation was evident. Cell activity studies showed that ground nickel titanium, spark oxidized and thermally oxidized (at 400 degrees C and below) had higher cellular activity and caused increased alkaline phosphatase (ALP) and osteocalcin (OC) expression which was comparable to control tissue culture plastic and titanium reference samples. Regardless of surface modifications, preimmersion of the samples in media for 72 h resulted in cell proliferation at the same level for all samples. Therefore, it can be concluded that preconditioning of samples alters surface properties and modulates the cell response regardless of the initial surface treatment and its properties. Moreover, a detrimental effect on cell response was observed after 7 and 14 days in culture for alkali treated samples. This was attributed to a high surface nickel concentration and a high nickel ion release rate from these surfaces. PMID:20024896

  6. Altered expression of epithelial cell surface glycoconjugates and intermediate filaments at the margins of mucosal wounds

    DEFF Research Database (Denmark)

    Dabelsteen, Erik; Grøn, B; Mandel, U;

    1998-01-01

    Alterations in cell to cell adhesion are necessary to enable the type of cell movements that are associated with epithelial wound healing and malignant invasion. Several studies of transformed cells have related epithelial cell movement to changes in the cell surface expression of the carbohydrat...

  7. Reproducibility of results of ultrasonic testing of welded joints of boiler heating surface tubes

    International Nuclear Information System (INIS)

    Reproducibility of the results of the ultrasonic inspection of welded joints of the heating surfaces of boilers depends substantially on the extent of differences between the frequency characteristics of selectors of the same type and on the spectrum of a probing signal. To assure the reproducibility and reliability of the results of the ultrasonic testing of the above joints it is necessary to ascertain the probing signal spectrum as the main parameter of the ultrasonic defectoscopy, and to standardize spectral characteristics of the selectors. The checking of the latter is carried out by means of a spectrum analyzer

  8. Air Processes Resulting in a Surface Layer Pollution in Industrial Regions

    Science.gov (United States)

    Lesin, Yu V.; Leshukov, T. V.

    2016-08-01

    The article describes the air quality research in Western Siberia (Kemerovo region). The problem of air quality preservation in the conditions of mining industry intensive development is caused by the weather conditions which lead either to the concentration of pollutants in the surface layer, or to their migration to other geosphere, or to dissipation as a result of convective mixing or advection of air masses. Zoning of the territory in view of the research results provides insight into areas where the greatest risk to human health and life is formed.

  9. Stable water isotope simulation by current land-surface schemes:Results of IPILPS phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Henderson-Sellers, A.; Fischer, M.; Aleinov, I.; McGuffie, K.; Riley, W.J.; Schmidt, G.A.; Sturm, K.; Yoshimura, K.; Irannejad, P.

    2005-10-31

    Phase 1 of isotopes in the Project for Intercomparison of Land-surface Parameterization Schemes (iPILPS) compares the simulation of two stable water isotopologues ({sup 1}H{sub 2} {sup 18}O and {sup 1}H{sup 2}H{sup 16}O) at the land-atmosphere interface. The simulations are off-line, with forcing from an isotopically enabled regional model for three locations selected to offer contrasting climates and ecotypes: an evergreen tropical forest, a sclerophyll eucalypt forest and a mixed deciduous wood. Here we report on the experimental framework, the quality control undertaken on the simulation results and the method of intercomparisons employed. The small number of available isotopically-enabled land-surface schemes (ILSSs) limits the drawing of strong conclusions but, despite this, there is shown to be benefit in undertaking this type of isotopic intercomparison. Although validation of isotopic simulations at the land surface must await more, and much more complete, observational campaigns, we find that the empirically-based Craig-Gordon parameterization (of isotopic fractionation during evaporation) gives adequately realistic isotopic simulations when incorporated in a wide range of land-surface codes. By introducing two new tools for understanding isotopic variability from the land surface, the Isotope Transfer Function and the iPILPS plot, we show that different hydrological parameterizations cause very different isotopic responses. We show that ILSS-simulated isotopic equilibrium is independent of the total water and energy budget (with respect to both equilibration time and state), but interestingly the partitioning of available energy and water is a function of the models' complexity.

  10. Soluble and cell surface receptors for tumor necrosis factor

    DEFF Research Database (Denmark)

    Wallach, D; Engelmann, H; Nophar, Y;

    1991-01-01

    Tumor necrosis factor (TNF) initiates its multiple effects on cell function by binding at a high affinity to specific cell surface receptors. Two different molecular species of these receptors, which are expressed differentially in different cells, have been identified. The cDNAs of both receptor...... have recently been cloned. Antibodies to one of these receptor species (the p55, type I receptor) can trigger a variety of TNF like effects by cross-linking of the receptor molecules. Thus, it is not TNF itself but its receptors that provide the signal for the response to this cytokine....... The intracellular domains of the two receptors differ in structure, suggesting that they mediate different activities. Their extracellular domains, however, are structurally related. Both contain cysteine-rich repeats which are homologous to repeated structures found in the extracellular domains of the nerve growth...... factor receptor and the CDw40 protein. Truncated soluble forms of the two receptors, corresponding to these cysteine-rich repeated structures, have been detected in human urine and were later found to be present also in the serum. The serum levels of those soluble TNF receptors increase dramatically...

  11. Regulation of ADAM12 cell-surface expression by protein kinase C epsilon

    DEFF Research Database (Denmark)

    Sundberg, Christina; Thodeti, Charles Kumar; Kveiborg, Marie;

    2004-01-01

    constitutively active protein. However, little is known about the regulation of ADAM12 cell-surface translocation. Here, we used human RD rhabdomyosarcoma cells, which express ADAM12 at the cell surface, in a temporal pattern. We report that protein kinase C (PKC) epsilon induces ADAM12 translocation to the cell......The ADAM (a disintegrin and metalloprotease) family consists of multidomain cell-surface proteins that have a major impact on cell behavior. These transmembrane-anchored proteins are synthesized as proforms that have (from the N terminus): a prodomain; a metalloprotease-, disintegrin......-immunoprecipitated from membrane-enriched fractions of PMA-treated cells, 3) RD cells transfected with EGFP-tagged, myristoylated PKCepsilon expressed more ADAM12 at the cell surface than did non-transfected cells, and 4) RD cells transfected with a kinase-inactive PKCepsilon mutant did not exhibit ADAM12 cell...

  12. Influence of surface charge on the potential toxicity of PLGA nanoparticles towards Calu-3 cells

    Directory of Open Access Journals (Sweden)

    Mura S

    2011-10-01

    Full Text Available Simona Mura1,2, Herve Hillaireau1,2, Julien Nicolas1,2, Benjamin Le Droumaguet1,2, Claire Gueutin1,2, Sandrine Zanna3, Nicolas Tsapis1,2, Elias Fattal1,2 1Univ Paris-Sud, UMR 8612, Châtenay Malabry, F-92296; 2CNRS, Châtenay Malabry, F-92296; 3Laboratoire de Physico-Chimie des Surfaces, CNRS-ENSCP (UMR 7045, Ecole Nationale Superiore de Chimie de Paris, France Background: Because of the described hazards related to inhalation of manufactured nanoparticles, we investigated the lung toxicity of biodegradable poly (lactide-co-glycolide (PLGA nanoparticles displaying various surface properties on human bronchial Calu-3 cells. Methods: Positively and negatively charged as well as neutral nanoparticles were tailored by coating their surface with chitosan, Poloxamer, or poly (vinyl alcohol, respectively. Nanoparticles were characterized in terms of size, zeta potential, and surface chemical composition, confirming modifications provided by hydrophilic polymers. Results: Although nanoparticle internalization by lung cells was clearly demonstrated, the cytotoxicity of the nanoparticles was very limited, with an absence of inflammatory response, regardless of the surface properties of the PLGA nanoparticles. Conclusion: These in vitro results highlight the safety of biodegradable PLGA nanoparticles in the bronchial epithelium and provide initial data on their potential effects and the risks associated with their use as nanomedicines. Keywords: nanoparticles, PLGA, surface properties, Calu-3, toxicity, inflammation

  13. BC Transit Fuel Cell Bus Project: Evaluation Results Report

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Post, M.

    2014-02-01

    This report evaluates a fuel cell electric bus demonstration led by British Columbia Transit (BC Transit) in Whistler, Canada. BC Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory to evaluate the buses in revenue service. This evaluation report covers two years of revenue service data on the buses from April 2011 through March 2013.

  14. Mechanism of initial attachment of corneal epithelial cells to polymeric surfaces.

    Science.gov (United States)

    Steele, J G; Johnson, G; Griesser, H J; Underwood, P A

    1997-12-01

    The initial attachment of cultured bovine corneal epithelial cells and stromal fibroblasts to two oxygen-containing synthetic polymers was studied. Cultured epithelial cells and stromal fibroblasts were seeded onto two oxygen-containing surfaces: 'tissue culture' polystyrene (TCPS) and a polymer film deposited by RF plasma deposition using a methylmethacrylate monomer (MMA/FEP). To establish the mechanism of cell attachment, the effect of the selective removal of the vitronectin and fibronectin from the serum used in the culture medium was tested. The attachment of cultured epithelial cells during the first 90 min of culture was reduced by 40% (TCPS)-80% (MMA/FEP) as a result of removing vitronectin from the medium. Attachment of these cells to TCPS was reduced by 85-95% when the serum was depleted of both fibronectin and vitronectin. However, depletion of fibronectin reduced cell attachment to TCPS by 20%, whilst on MMA/FEP cell attachment was equivalent, or higher, than that for intact serum. The attachment of cultured corneal stromal fibroblasts was similarly dependent on vitronectin but less dependent on fibronectin. Therefore, for the attachment of both cultured epithelial cells and fibroblasts to oxygen-containing surfaces in the presence of serum, there is a high requirement for serum vitronectin but a lesser requirement for fibronectin. The effects of the establishment of corneal epithelial cells in culture and the site of origin of the cells, were determined. Primary isolates of epithelial cells isolated from the limbal, central or peripheral regions of the cornea were less dependent on vitronectin for initial attachment to TCPS than were these cells after several passages in culture. Furthermore, the primary isolates were dramatically less responsive to vitronectin than the cultured cells. These results indicate that the mechanism of attachment of corneal epithelial cells to TCPS varies with the culture experience of the cells. Cells that are culture

  15. Surface heat budget over the Weddell Sea: Buoy results and model comparisons

    Science.gov (United States)

    Vihma, Timo; Uotila, Juha; Cheng, Bin; Launiainen, Jouko

    2002-02-01

    The surface heat budget over the Weddell Sea ice cover in 1996 was studied on the basis of data from Argos buoys equipped with meteorological sensors. In addition, a thermodynamic sea ice model, satellite-based data on the sea ice concentration, sonar results on ice thickness distribution, and output from large-scale meteorological models were all utilized. Applying the buoy data, the sensible heat flux over sea ice was calculated by Monin-Obukhov theory using the gradient method, and the latent heat flux was obtained by the bulk method. A second estimate for the surface fluxes was obtained from the thermodynamic sea ice model, which was forced by the buoy observations. The results showed a reasonable agreement. The dominating component in the heat budget over ice was the net longwave radiation, which had a mean annual cooling effect of -28 W m-2. This was balanced by the net shortwave radiation (annual mean 13 W m-2), the sensible (13 W m-2) and latent (-3 W m-2) heat fluxes, and the conductive heat flux through the ice (5 W m-2). The regional surface fluxes over the fractured ice cover were estimated using the buoy data and Special Sensor Microwave Imager (SSMI)-derived ice concentrations. In winter the regional surface sensible heat flux was sensitive to the ice concentration and thickness distribution. The estimate for the area-averaged formation rate of new ice in leads in winter varies from 0.05 to 0.21 m per month depending on the SSMI processing algorithm applied. Countergradient fluxes occurred 8-10% of the time. The buoy observations were compared with the operational analyses of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the reanalyses of the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR). The 2 m air temperature and surface temperature were 3.5° and 4.4°C too high, respectively, in the ECMWF and 3.2° and 3.0°C too low in the NCEP/NCAR fields, but the models reproduced the

  16. [Three photons quantum-cutting system on the rear surface of cells to improve the efficiencies of solar cells].

    Science.gov (United States)

    Yao, Wen-ting; Chen, Xiao-bo; Cheng, Huan-li; Zhou, Gu; Deng, Zhi-wei; Li, Yong-liang; Yan, Da-dong; Peng, Fang-lin

    2015-02-01

    The authors present a solar cell model with a three photons quantum-cutting system on the rear surface, then the method of calculation of limiting efficiencies was used to get the maximum efficiency 58.58% at the band gap Eg=0.9315 eV, and in contrast with two-photons quantum-cutting system, it is greatly improved. The result can prove that the three-photons quantum-cutting has a great sense to improve the efficiencies of solar cells. It is the exciting development for us to find out the useful luminescence materials to get the high efficiency.

  17. Insolation and Resulting Surface Temperatures of the Kuiper-Rudaki Study Region on Mercury.

    Science.gov (United States)

    Bauch, Karin E.; Hiesinger, Harald; D'Amore, Mario; Helbert, Jörn; Weinauer, Julia

    2016-04-01

    The imaging spectrometer MERTIS (Mercury Radiometer and Thermal Infrared Spectrometer) is part of the payload of ESA's BepiColombo mission, which is scheduled for launch in 2017 [1]. The instrument consists of an IR-spectrometer and radiometer, which observe the surface in the wavelength range of 7-14 and 7-40μm, respectively. The four scientific objectives are to a) study Mercury's surface composition, b) identify rock-forming minerals, c) globally map the surface mineralogy and d) study surface temperature and thermal inertia [1, 2]. In preparation of the MERTIS experiment, we performed detailed thermal models of the lunar surface, which we extrapolated to Mercury. In order to calculate insolation and surface temperatures, we use a numerical model, which has been described by [7]. Surface temperatures are dependent on the surface and subsurface bulk thermophysical properties, such as bulk density, heat capacity, thermal conductivity, emissivity, topography, and albedo. Lunar and Mercurian surface temperatures show the same general characteristics. Both have very steep temperature gradients at sunrise and sunset, due to the lack of an atmosphere. However, there are major differences due to the orbital characteristics. On Mercury the 3:2 resonant rotation rate and the eccentric orbit causes local noon at longitudes 0° and 180° to coincide with perihelion, which leads to "hot poles". At longitudes 90° and 270° , local noon coincides with aphelion, which results in "cold poles" [8]. At these longitudes brief secondary sunrises and sunsets are visible, when Mercury's orbital angular velocity exceeds the spin rate during perihelion [8]. Here we present diurnal temperature curves of the Kuiper-Rudaki study region, based on thermophysical estimates and MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging [9]) albedo data with a resolution of 1000m/px. Our study region spans more than 90° along the equator, thus allowing us to study both, hot and

  18. Surface-Induced Turbulence and Resulting Sand Suspension Beneath Breaking Waves

    Science.gov (United States)

    Brinkkemper, J.; Ruessink, G.

    2014-12-01

    Breaking waves and bores inject large amounts of turbulence into the water column as vortices, which can travel downward and entrain sand from the bed. Coastal evolution models rarely include the effect of this surface-induced turbulence on sand suspension and subsequent transport to predict surf-zone morphodynamics. Here, we analyze turbulence and suspension measurements beneath non-breaking waves and plunging breakers, collected during the field-scale BARDEXII laboratory experiment using a vertical array of 3 ADVs and 7 OBSs. The array was positioned at a single cross-shore location, but, because of changes in wave conditions and water levels, experienced different degrees of wave breaking. Results show a phase-coupling for both turbulence kinetic energy and sand concentration with the short-wave orbital motion during all conditions, with the highest values when the cross-shore velocity is onshore directed. The vertical turbulence flux under plunging breakers also depends on wave phase, with a downward and upward flux during offshore and onshore directed wave orbital motion, respectively. The plunging jet hits the water surface in the wave trough, resulting in a downward turbulence flux during the offshore directed wave orbital motion. The upward flux during the onshore directed wave orbital motion might represent the injected air bubbles rising to the water surface. This upward flux coincides with the peak in suspension, which, accordingly, reaches higher in the water column than beneath non-breaking waves. Besides a phase-coupling with the short-wave orbital motion, turbulence kinetic energy and sand concentration were also modulated on an infragravity timescale, with high values during the offshore directed infragravity flow. The effect of surface-generated turbulence on the direction and magnitude of short- and infragravity-induced cross-shore sand fluxes will also be discussed. This research is supported by the Dutch Technology Foundation STW, which is part

  19. Cell surface N-glycans influence the level of functional E-cadherin at the cell–cell border

    OpenAIRE

    M Kristen Hall; Douglas A Weidner; Sahil Dayal; Ruth A. Schwalbe

    2014-01-01

    E-cadherin is crucial for adhesion of cells to each other and thereby development and maintenance of tissue. While it is has been established that N-glycans inside the cell impact the level of E-cadherin at the cell surface of epithelial-derived cells, it is unclear whether N-glycans outside the cell control the clustering of E-cadherin at the cell–cell border. Here, we demonstrate reduction of N-glycans at the cell surface weakened the recruitment and retention of E-cadherin at the cell–cell...

  20. Motion of cells sedimenting on a solid surface in a laminar shear flow.

    Science.gov (United States)

    Tissot, O; Pierres, A; Foa, C; Delaage, M; Bongrand, P

    1992-01-01

    Cell adhesion often occurs under dynamic conditions, as in flowing blood. A quantitative understanding of this process requires accurate knowledge of the topographical relationships between the cell membrane and potentially adhesive surfaces. This report describes an experimental study made on both the translational and rotational velocities of leukocytes sedimenting of a flat surface under laminar shear flow. The main conclusions are as follows: (a) Cells move close to the wall with constant velocity for several tens of seconds. (b) The numerical values of translational and rotational velocities are inconsistent with Goldman's model of a neutrally buoyant sphere in a laminar shear flow, unless a drag force corresponding to contact friction between cells and the chamber floor is added. The phenomenological friction coefficient was 7.4 millinewton.s/m. (c) Using a modified Goldman's theory, the width of the gap separating cells (6 microns radius) from the chamber floor was estimated at 1.4 micron. (d) It is shown that a high value of the cell-to-substrate gap may be accounted for by the presence of cell surface protrusions of a few micrometer length, in accordance with electron microscope observations performed on the same cell population. (e) In association with previously reported data (Tissot, O., C. Foa, C. Capo, H. Brailly, M. Delaage, and P. Bongrand. 1991. Biocolloids and Biosurfaces. In press), these results are consistent with the possibility that cell-substrate attachment be initiated by the formation of a single molecular bond, which might be considered as the rate limiting step.

  1. Signal peptide cleavage is essential for surface expression of a regulatory T cell surface protein, leucine rich repeat containing 32 (LRRC32

    Directory of Open Access Journals (Sweden)

    Sugiyama Hideaki

    2011-05-01

    Full Text Available Abstract Background Elevated numbers of regulatory T cells (Tregs have been implicated in certain cancers. Depletion of Tregs has been shown to increase anti-tumor immunity. Tregs also play a critical role in the suppression of autoimmune responses. The study of Tregs has been hampered by a lack of adequate surface markers. Leucine Rich Repeat Containing 32 (LRRC32, also known as Glycoprotein A Repetitions Predominant (GARP, has been postulated as a novel surface marker of activated Tregs. However, there is limited information regarding the processing of LRRC32 or the regulatory phenotype and functional activity of Tregs expressing LRRC32. Results Using naturally-occurring freshly isolated Tregs, we demonstrate that low levels of LRRC32 are present intracellularly prior to activation and that freshly isolated LRRC32+ Tregs are distinct from LRRC32- Tregs with respect to the expression of surface CD62L. Using LRRC32 transfectants of HEK cells, we demonstrate that the N-terminus of LRRC32 is cleaved prior to expression of the protein at the cell surface. Furthermore, we demonstrate using a construct containing a deleted putative signal peptide region that the presence of a signal peptide region is critical to cell surface expression of LRRC32. Finally, mixed lymphocyte assays demonstrate that LRRC32+ Tregs are more potent suppressors than LRRC32- Tregs. Conclusions A cleaved signal peptide site in LRRC32 is necessary for surface localization of native LRRC32 following activation of naturally-occurring freshly-isolated regulatory T cells. LRRC32 expression appears to alter the surface expression of activation markers of T cells such as CD62L. LRRC32 surface expression may be useful as a marker that selects for more potent Treg populations. In summary, understanding the processing and expression of LRRC32 may provide insight into the mechanism of action of Tregs and the refinement of immunotherapeutic strategies aimed at targeting these cells.

  2. Nanofiber-modified surface directed cell migration and orientation in microsystem

    Science.gov (United States)

    Zhang, Xu; Gao, Xinghua; Jiang, Lei; Zhang, Xulang; Qin, Jianhua

    2011-01-01

    Cell-microscale pattern surface interactions are crucial to understand many fundamental biological questions and develop regenerative medicine and tissue engineering approaches. In this work, we demonstrated a simple method to pattern PDMS surface by sacrificing poly vinyl pyrrolidone (PVP) electrospinning nanofibers and investigated the growth profile of cells on the modified patterned surfaces using stroma cells. The stromal cells were observed to exhibit good viability on this modified surface and the patterned surface with alignment nanofibers could promote cell migration. Furthermore, the modified PDMS surface was integrated with microfluidic channels to create the microscale spatial factor and was used to explore the cell migration and orientation under this microsystem. Both spatial factor and patterned surfaces were found to contribute to the complex cell orientation under the combined dual effects. This established method is simple, fast, and easy for use, demonstrating the potential of this microsystem for applications in addressing biological questions in complex environment. PMID:22662030

  3. In-cell thermodynamics and a new role for protein surfaces.

    Science.gov (United States)

    Smith, Austin E; Zhou, Larry Z; Gorensek, Annelise H; Senske, Michael; Pielak, Gary J

    2016-02-16

    There is abundant, physiologically relevant knowledge about protein cores; they are hydrophobic, exquisitely well packed, and nearly all hydrogen bonds are satisfied. An equivalent understanding of protein surfaces has remained elusive because proteins are almost exclusively studied in vitro in simple aqueous solutions. Here, we establish the essential physiological roles played by protein surfaces by measuring the equilibrium thermodynamics and kinetics of protein folding in the complex environment of living Escherichia coli cells, and under physiologically relevant in vitro conditions. Fluorine NMR data on the 7-kDa globular N-terminal SH3 domain of Drosophila signal transduction protein drk (SH3) show that charge-charge interactions are fundamental to protein stability and folding kinetics in cells. Our results contradict predictions from accepted theories of macromolecular crowding and show that cosolutes commonly used to mimic the cellular interior do not yield physiologically relevant information. As such, we provide the foundation for a complete picture of protein chemistry in cells.

  4. Assessment of Automated Analyses of Cell Migration on Flat and Nanostructured Surfaces

    Directory of Open Access Journals (Sweden)

    Hans A Kestler

    2012-07-01

    Full Text Available Motility studies of cells often rely on computer software that analyzes time-lapse recorded movies and establishes cell trajectories fully automatically. This raises the question of reproducibility of results, since different programs could yield significantly different results of such automated analysis. The fact that the segmentation routines of such programs are often challenged by nanostructured surfaces makes the question more pertinent. Here we illustrate how it is possible to track cells on bright field microscopy images with image analysis routines implemented in an open-source cell tracking program, PACT (Program for Automated Cell Tracking. We compare the automated motility analysis of three cell tracking programs, PACT, Autozell, and TLA, using the same movies as input for all three programs. We find that different programs track overlapping, but different subsets of cells due to different segmentation methods. Unfortunately, population averages based on such different cell populations, differ significantly in some cases. Thus, results obtained with one software package are not necessarily reproducible by other software.

  5. Analytical Round Robin for Elastic-Plastic Analysis of Surface Cracked Plates: Phase I Results

    Science.gov (United States)

    Wells, D. N.; Allen, P. A.

    2012-01-01

    An analytical round robin for the elastic-plastic analysis of surface cracks in flat plates was conducted with 15 participants. Experimental results from a surface crack tension test in 2219-T8 aluminum plate provided the basis for the inter-laboratory study (ILS). The study proceeded in a blind fashion given that the analysis methodology was not specified to the participants, and key experimental results were withheld. This approach allowed the ILS to serve as a current measure of the state of the art for elastic-plastic fracture mechanics analysis. The analytical results and the associated methodologies were collected for comparison, and sources of variability were studied and isolated. The results of the study revealed that the J-integral analysis methodology using the domain integral method is robust, providing reliable J-integral values without being overly sensitive to modeling details. General modeling choices such as analysis code, model size (mesh density), crack tip meshing, or boundary conditions, were not found to be sources of significant variability. For analyses controlled only by far-field boundary conditions, the greatest source of variability in the J-integral assessment is introduced through the constitutive model. This variability can be substantially reduced by using crack mouth opening displacements to anchor the assessment. Conclusions provide recommendations for analysis standardization.

  6. BC Transit Fuel Cell Bus Project Evaluation Results: Second Report

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Post, M.

    2014-09-01

    Second report evaluating a fuel cell electric bus (FCEB) demonstration led by British Columbia Transit (BC Transit) in Whistler, Canada. BC Transit is collaborating with the California Air Resources Board and the U.S. Department of Energy's National Renewable Energy Laboratory to evaluate the buses in revenue service. NREL published its first report on the demonstration in February 2014. This report is an update to the previous report; it covers 3 full years of revenue service data on the buses from April 2011 through March 2014 and focuses on the final experiences and lessons learned.

  7. RNA computers in live cells: results and prospects

    OpenAIRE

    Benenson, Yaakov

    2009-01-01

    Man-made molecular “computers” that operate inside live cells will enable unprecedented level of control over cellular physiology. A promising approach to building these computers uses RNA molecules and RNA-based regulation. RNA naturally lends itself to create “digital” molecular networks that embody standardized (normal) forms of logic functions. The network’s inputs, that may or may not be inverted by single-input NOT logic gates, feed into multi-input AND gates whose outputs are in turn i...

  8. Favourable results of Mohs micrographic surgery for basal cell carcinoma

    DEFF Research Database (Denmark)

    Gniadecki, Robert; Glud, Martin; Mortensen, Kia;

    2015-01-01

    INTRODUCTION: Basal cell carcinoma (BCC) is the most common malignant neoplasm with an annual incidence approaching 200/100,000 person-years. Mohs micrographic surgery (MMS) is widely used in North America and in Europe for treatment of BCC. This technique ensures radical tumour removal, sparing...... defects than standard excisions with 4 or 6 mm margins. Closure of skin defects was achieved by side-to-side closure in 49% and by local flaps in 40%. There were no relapses during the observation time. The safety, cosmetic and functional outcome were excellent. CONCLUSIONS: We recommend that MMS...

  9. Mercury reduction and cell-surface adsorption by Geobacter sulfurreducens PCA

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Haiyan [ORNL; Lin, Hui [ORNL; Zheng, Wang [ORNL; Feng, Xinbin [ORNL; Liang, Liyuan [ORNL; Elias, Dwayne A [ORNL; Gu, Baohua [ORNL

    2013-01-01

    Both reduction and surface adsorption of mercuric mercury [Hg(II)] are found to occur simultaneously on G. sulfurreducens PCA cells under dark, anaerobic conditions. Reduction of Hg(II) to elemental Hg(0) initially follows a pseudo-first order kinetics with a half-life of < 2 h in the presence of 50 nM Hg(II) and 1011 cells L-1 in a phosphate buffer (pH 7.4). Multiple gene deletions of the outer membrane cytochromes in this organism resulted in decrease in reduction rate from ~ 0.3 to 0.05 h-1, and reduction was nearly absent with heat-killed cells or in the cell filtrate. Adsorption of Hg(II) by cells is found to compete with, and thus inhibit, Hg(II) reduction. Depending on the Hg to cell ratio, maximum Hg(II) reduction was observed at about 5 10-19 mol Hg cell-1, but reduction terminated at a low Hg to cell ratio (< 10-20 mol Hg cell-1). This inhibitory effect is attributed to strong binding between Hg(II) and the thiol ( SH) functional groups on cells and validated by experiments in which the sorbed Hg(II) was readily exchanged by thiols (e.g., glutathione) but not by carboxylic ligands such as ethylenediaminetetraacetate (EDTA). We suggest that coupled Hg(II)-cell interactions, i.e., reduction and surface binding, could be important in controlling Hg species transformation and bioavailability and should therefore be considered in microbial Hg(II) uptake and methylation studies.

  10. Cell adhesion behavior on the silicone rubber surface modified by using ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, In Tae; Jung, Chan Hee; Nh, Young Chang; Choi, Jae Hak [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kuk, In Seol [Hanyang University, Seoul (Korea, Republic of); An, Mi Young [Chungnam National University, Daejeon (Korea, Republic of)

    2009-12-15

    In this study we studied cell adhesion and proliferation on the surface of a silicone rubber modified by ion beam irradiation. The surface property of the irradiated silicone rubber was characterized by water contact angle and FT-IR analyses. It was observed that human (HEK293) fibroblast cells exhibit strong adhesion to the irradiated silicone surface. This enhanced adhesion of mammalian cells can be attributed to the increase in the hydrophilicity of the silicone surface by ion beam irradiation.

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

    Science.gov (United States)

    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

  12. Cell attachment of polypropylene surface-modified by COOH+ ion implantation

    International Nuclear Information System (INIS)

    Carboxy ion (COOH+) implantation was performed at the energy of 50 keV with fluences ranging from 1x1014 to 1x1015 ions/cm2 at room temperature for polypropylene (PP). The effects of ion implantation on cells (immune macrophages, 3T3 mouse fibroblasts and human endothelial cells) were studied in vitro. Tests of cell attachment gave interesting results that the 3T3 mouse fibroblasts and human endothelial cells cultured on the surface of the implanted PP showed much better attachment and proliferation than that on pristine PP. At the same time, the COOH+ ion implantation also induced low macrophage attachment with normal cellular morphology. Results of X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) analysis showed that COOH+ ion implantation caused the rearrangement of chemical bonds and the formation of some new O-containing groups, which was responsible for the enhancement of the biocompatibility of PP

  13. A yeast surface display system for the discovery of ligands that trigger cell activation.

    Science.gov (United States)

    Cho, B K; Kieke, M C; Boder, E T; Wittrup, K D; Kranz, D M

    1998-11-01

    Opposing cells often communicate signalling events using multivalent interactions between receptors present on their cell surface. For example, T cells are typically activated when the T cell receptor (TCR) and its associated costimulatory molecules are multivalently engaged by the appropriate ligands present on an antigen presenting cell. In this report, yeast expressing high cell-surface levels of a TCR ligand (a recombinant antibody to the TCR Vbeta domain) were shown to act as 'pseudo' antigen presenting cells and induce T cell activation as monitored by increased levels of CD25 and CD69 and by downregulation of cell surface TCR. Similar levels of T cell activation could occur even when a 30-fold excess of irrelevant yeast was present, suggesting that such a yeast display system, by virtue of its ability to present ligands multivalently, may be used in highly sensitive procedures to identify novel polypeptides that interact multivalently with cell surface receptors and thereby trigger specific cellular responses.

  14. Determination of aerodynamic parameters of urban surfaces: methods and results revisited

    Science.gov (United States)

    Mohammad, A. F.; Zaki, S. A.; Hagishima, A.; Ali, M. S. M.

    2015-11-01

    Estimates of aerodynamic parameters, in particular roughness length z 0 and displacement height d, are important for the analysis of the roughness of an urban surface, which affects processes that occur within the urban boundary layer such as pollutant dispersion and urban ventilation. Findings regarding the aerodynamic effects of various configurations of urban arrays were compiled from various studies. Several experimental, numerical and semi-empirical studies to estimate z 0 and d were reviewed and compared with each other. The results can be summarized as follows: (1) the influence of the frontal area index ( λ f ) on z 0 is significant and their relationship has been confirmed by both experimental and numerical data; (2) compared to one-parameter and two-parameter fitting methods, the three-parameter fitting method is the least accurate; (3) the physical meaning of d remains vague because its definition as the height where surface drag acts may not be accurate for sharp-edged roughness blocks and (4) the peak values of z 0 for uniform and heterogeneous block heights indicate presence of skimming or wake-interference flow effects, which may influence surface roughness. Finally, the semi-empirical models were found to be limited to cases derived from available experimental data, which normally involve uniform arrays of cubes.

  15. Transitioning MODIS to VIIRS observations for Land: Surface Reflectance results, Status and Long-term Prospective

    Science.gov (United States)

    Vermote, E.

    2015-12-01

    Surface reflectance is one of the key products from VIIRS and as with MODIS, is used in developing several higher-order land products. The VIIRS Surface Reflectance (SR) IP is based on the heritage MODIS Collection 5 product (Vermote et al. 2002). The quality and character of surface reflectance depends on the accuracy of the VIIRS Cloud Mask (VCM) and aerosol algorithms and of course on the adequate calibration of the sensor. Early evaluation of the VIIRS SR product in the context of the maturity of the operational processing system known as the Interface Data Processing System (IDPS), has been a major focus of work to-date, but is now evolving into the development of a VIIRS suite of Climate Data Records produced by the NASA Land Science Investigator Processing System (SIPS). We will present the calibration performance and the role of the surface reflectance in calibration monitoring, the performance of the cloud mask with a focus on vegetation monitoring (no snow conditions), the performance of the aerosol input used in the atmospheric correction with quantitative results of the performance of the SR product over AERONET sites. Based on those elements and further assessment, we will address the readiness of the SR product for the production of higher-order land products such as Vegetation Indices, Albedo and LAI/FPAR, the its application to agricultural monitoring and in particular the integration of VIIRS data into the global agricultural monitoring (GLAM) system developed at UMd. Finally from the lessons learned, we will articulate a set of critical recommendations to ensure consistency and continuity of the JPSS mission with the MODIS data record.

  16. Effects of Surface Morphology ZnAl2O4 of Ceramic Materials on Osteoblastic Cells Responses

    International Nuclear Information System (INIS)

    Ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. The purpose of this study was to investigate the effect of surface morphology of nano structure thin films of ZnAl2O4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl2O4 prepared by chemical coprecipitation reaction on the in vitro cell adhesion, viability, and cell-material interactions of osteoblastic cells. Our result showed that cell attachment was significantly enhanced from 60 to 80% on the ZnAl2O4 nano structured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nano structure ceramic improves cell-material interaction with enhanced spreading and filopodia with multiple cellular extensions on the surface of the ceramic and enhancing cell viability/proliferation in comparison with bulk ceramic surfaces used as control. Altogether, these results suggest that zinc aluminate nano structured materials have a great potential to be used in dental implant and bone substitute applications.Ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. The purpose of this study was to investigate the effect of surface morphology of nano structure thin films of ZnAl2O4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl2O4 prepared by chemical coprecipitation reaction on the in vitro cell adhesion, viability, and cell-material interactions of osteoblastic cells. Our result showed that cell attachment was significantly enhanced from 60 to 80% on the ZnAl2O4 nano structured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nano structure ceramic improves cell

  17. DNA damage response to different surface chemistry of silver nanoparticles in mammalian cells

    International Nuclear Information System (INIS)

    Silver nanoparticles (Ag NPs) have recently received much attention for their possible applications in biotechnology and life sciences. Ag NPs are of interest to defense and engineering programs for new material applications as well as for commercial purposes as an antimicrobial. However, little is known about the genotoxicity of Ag NPs following exposure to mammalian cells. This study was undertaken to examine the DNA damage response to polysaccharide surface functionalized (coated) and non-functionalized (uncoated) Ag NPs in two types of mammalian cells; mouse embryonic stem (mES) cells and mouse embryonic fibroblasts (MEF). Both types of Ag NPs up-regulated the cell cycle checkpoint protein p53 and DNA damage repair proteins Rad51 and phosphorylated-H2AX expression. Furthermore both of them induced cell death as measured by the annexin V protein expression and MTT assay. Our observations also suggested that the different surface chemistry of Ag NPs induce different DNA damage response: coated Ag NPs exhibited more severe damage than uncoated Ag NPs. The results suggest that polysaccharide coated particles are more individually distributed while agglomeration of the uncoated particles limits the surface area availability and access to membrane bound organelles

  18. Experimental results on plasma interactions with large surfaces at high voltages

    Science.gov (United States)

    Grier, N. T.

    1980-01-01

    Multikilowatt power levels for future payloads can be more efficiently generated using solar arrays operating in the kilovolt range. This implies that large areas of the array at high operating voltages will be exposed to the space plasma environment. The resulting interactions of these high voltage surfaces with space plasma environments can seriously impact the performance of the satellite system. The plasma-surface interaction phenomena were studied in tests performed in two separate vacuum chambers, a 4.6 m diameter by 19.2 long chamber and a 20 m diameter by 27.4 m long chamber. The generated plasma density was approximately 1x10 to the 4th power/cu cm. Ten solar array panels, each with areas of 1400 sq cm were used in the tests. Nine of the solar panels were tested as a composite unit in the form of a 3x3 solar panel matrix. The results from all the tests confirmed small sample tests results: insulators were found to enhance the plasma coupling current for high positive bias and arcing was found to occur at high negative bias.

  19. Influence of the Structure of the Titanium Oxide Coating Surface on Immunocompetent Tumor Cells

    Science.gov (United States)

    Khlusov, I. A.; Sharkeev, Yu. P.; Pichugin, V. F.; Legostaeva, E. V.; Litvinova, L. S.; Shupletsova, V. V.; Sokhonevich, N. A.; Khaziakhmatova, O. G.; Khlusova, M. Yu.; Gutor, S. S.; Tolkacheva, T. V.

    2016-03-01

    Results of a study of the properties of titanium oxide based coatings deposited on titanium substrates by microarc oxidation are presented that establish a relationship between physical and mechanical properties of the coating surface and their medical and biological properties. The required surface topography is formed by sandblasting of the substrate and is controlled by values of the roughness index Ra. A linear dependence of the amplitude of negative electrostatic potential of the oxide coating on the Ra value is established. The topography of the micro-arc coating surface determines its negative surface potential that apparently reduces the viability of the leukemia T cells of the Jurkat line via electrostatic and biological mechanisms unrelated to the generation of intracellular reactive oxygen species.

  20. Ionized dopant concentrations at the heavily doped surface of a silicon solar cell

    Science.gov (United States)

    Weinberg, I.; Broder, J. D.; Mazaris, G. A., Jr.; Hsu, L.

    1978-01-01

    Data are combined with concentrations obtained by a bulk measurement method using successive layer removal with measurements of Hall effect and resistivity. From the MOS (metal-oxide-semiconductor) measurements it is found that the ionized dopant concentration N has the value (1.4 + or - 0.1) x 10 to the 20th power/cu cm at distances between 100 and 220 nm from the n(+) surface. The bulk measurement technique yields average values of N over layers whose thickness is 2000 nm. Results show that, at the higher concentrations encountered at the n(+) surface, the MOS C-V technique, when combined with a bulk measurement method, can be used to evaluate the effects of materials preparation methodologies on the surface and near surface concentrations of silicon cells.

  1. Fuel Cell Vehicle Learning Demonstration: Spring 2008 Results; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wipke, K.; Sprik, S.; Kurtz, J.; Garbak, J.

    2008-04-01

    Conference paper presented at the 2008 National Hydrogen Association Meeting that describes the spring, 2008 results of the Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project.

  2. Impaired cell surface expression of HLA-B antigens on mesenchymal stem cells and muscle cell progenitors

    DEFF Research Database (Denmark)

    Isa, Adiba; Nehlin, Jan; Sabir, Hardee Jawad;

    2010-01-01

    HLA class-I expression is weak in embryonic stem cells but increases rapidly during lineage progression. It is unknown whether all three classical HLA class-I antigens follow the same developmental program. In the present study, we investigated allele-specific expression of HLA-A, -B, and -C...... at the mRNA and protein levels on human mesenchymal stem cells from bone marrow and adipose tissue as well as striated muscle satellite cells and lymphocytes. Using multicolour flow cytometry, we found high cell surface expression of HLA-A on all stem cells and PBMC examined. Surprisingly, HLA-B was either...... undetectable or very weakly expressed on all stem cells protecting them from complement-dependent cytotoxicity (CDC) using relevant human anti-B and anti-Cw sera. IFNgamma stimulation for 48-72 h was required to induce full HLA-B protein expression. Quantitative real-time RT-PCR showed that IFNgamma induced...

  3. Control of Cross Talk between Angiogenesis and Inflammation by Mesenchymal Stem Cells for the Treatment of Ocular Surface Diseases

    Directory of Open Access Journals (Sweden)

    Fei Li

    2016-01-01

    Full Text Available Angiogenesis is beneficial in the treatment of ischemic heart disease and peripheral artery disease. However, it facilitates inflammatory cell filtration and inflammation cascade that disrupt the immune and angiogenesis privilege of the avascular cornea, resulting in ocular surface diseases and even vision loss. Although great progress has been achieved, healing of severe ocular surface injury and immunosuppression of corneal transplantation are the most difficult and challenging step in the treatment of ocular surface disorders. Mesenchymal stem cells (MSCs, derived from various adult tissues, are able to differentiate into different cell types such as endothelial cells and fat cells. Although it is still under debate whether MSCs could give rise to functional corneal cells, recent results from different study groups showed that MSCs could improve corneal disease recovery through suppression of inflammation and modulation of immune cells. Thus, MSCs could become a promising tool for ocular surface disorders. In this review, we discussed how angiogenesis and inflammation are orchestrated in the pathogenesis of ocular surface disease. We overviewed and updated the knowledge of MSCs and then summarized the therapeutic potential of MSCs via control of angiogenesis, inflammation, and immune response in the treatment of ocular surface disease.

  4. Small round blue cell tumours: diagnostic and prognostic usefulness of the expression of B7-H3 surface molecule

    OpenAIRE

    Gregorio, A.; Corrias, M V; R. Castriconi; Dondero, A; Mosconi, M.; Gambini, C; Moretta, A; Moretta, L; Bottino, C

    2008-01-01

    Aims: To assess whether the expression of B7-H3 surface molecule could improve differential diagnosis of small cell round tumours. Methods and results: One hundred and one well-characterized paraffin-embedded small round cell tumours, stored in the pathology archive of the Gaslini Institute, were immunohistochemically analysed with the 5B14 monoclonal antibody, which recognizes the surface molecule B7-H3. All lymphoblastic lymphomas and the blastematous component of Wilms’ tumours were comple...

  5. A simplified model for dynamics of cell rolling and cell-surface adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Cimrák, Ivan, E-mail: ivan.cimrak@fri.uniza.sk [Cell-in-fluid Research Group, http://cell-in-fluid.fri.uniza.sk Faculty of Management Science and Informatics, University of Žilina Univerzitná 8215/1, 010 26 Žilina (Slovakia)

    2015-03-10

    We propose a three dimensional model for the adhesion and rolling of biological cells on surfaces. We study cells moving in shear flow above a wall to which they can adhere via specific receptor-ligand bonds based on receptors from selectin as well as integrin family. The computational fluid dynamics are governed by the lattice-Boltzmann method. The movement and the deformation of the cells is described by the immersed boundary method. Both methods are fully coupled by implementing a two-way fluid-structure interaction. The adhesion mechanism is modelled by adhesive bonds including stochastic rules for their creation and rupture. We explore a simplified model with dissociation rate independent of the length of the bonds. We demonstrate that this model is able to resemble the mesoscopic properties, such as velocity of rolling cells.

  6. Micropatterned polysaccharide surfaces via laser ablation for cell guidance

    Energy Technology Data Exchange (ETDEWEB)

    Barbucci, Rolando; Lamponi, Stefania; Pasqui, Daniela; Rossi, Antonella; Weber, Elisabetta

    2003-03-03

    Micropatterned materials were obtained by a controlled laser ablation of a photoimmobilised homogeneous layer of hyaluronic acid (Hyal) and its sulphated derivative (HyalS). The photoimmobilisation was performed by coating the polysaccharide, adequately functionalised with a photoreactive group, on aminosilanised glass substrate and immobilising it on the surface under UV light. Hyal or HyalS photoimmobilised samples were then subjected to laser ablation with wavelengths in the UV regions in order to drill the pattern. Four different patterns with stripes of 100, 50, 25 and 10 {mu}m were generated. A chemical characterisation by attenuated total reflection/Fourier transform infrared (ATR/FT-IR) and time of flight-secondary ions mass spectrometry (TOF-SIMS) confirmed the success of the laser ablation procedure and the presence of alternating stripes of polysaccharide and native glass. The exact dimensions of the stripes were determined by atomic force microscopy. The analysis of cell behaviour in terms of adhesion, proliferation and movement using mouse fibroblasts (3T3 line) and bovine aortic endothelial cells (BAEC) was also performed.

  7. Effects of DNP on the cell surface properties of marine bacteria and its implication for adhesion to surfaces

    Digital Repository Service at National Institute of Oceanography (India)

    Jain, A.; Nishad, K.K.; Bhosle, N.B.

    The effect of 2, 4-dinitrophenol (DNP) on extracelluar polysaccharides (EPS), cell surface charge, and hydrophobicity of six marine bacterial cultures was studied, and its influence on attachment of these bacteria to glass and polystyrene...

  8. High Cell Surface Death Receptor Expression Determines Type I Versus Type II Signaling*

    Science.gov (United States)

    Meng, Xue Wei; Peterson, Kevin L.; Dai, Haiming; Schneider, Paula; Lee, Sun-Hee; Zhang, Jin-San; Koenig, Alexander; Bronk, Steve; Billadeau, Daniel D.; Gores, Gregory J.; Kaufmann, Scott H.

    2011-01-01

    Previous studies have suggested that there are two signaling pathways leading from ligation of the Fas receptor to induction of apoptosis. Type I signaling involves Fas ligand-induced recruitment of large amounts of FADD (FAS-associated death domain protein) and procaspase 8, leading to direct activation of caspase 3, whereas type II signaling involves Bid-mediated mitochondrial perturbation to amplify a more modest death receptor-initiated signal. The biochemical basis for this dichotomy has previously been unclear. Here we show that type I cells have a longer half-life for Fas message and express higher amounts of cell surface Fas, explaining the increased recruitment of FADD and subsequent signaling. Moreover, we demonstrate that cells with type II Fas signaling (Jurkat or HCT-15) can signal through a type I pathway upon forced receptor overexpression and that shRNA-mediated Fas down-regulation converts cells with type I signaling (A498) to type II signaling. Importantly, the same cells can exhibit type I signaling for Fas and type II signaling for TRAIL (TNF-α-related apoptosis-inducing ligand), indicating that the choice of signaling pathway is related to the specific receptor, not some other cellular feature. Additional experiments revealed that up-regulation of cell surface death receptor 5 levels by treatment with 7-ethyl-10-hydroxy-camptothecin converted TRAIL signaling in HCT116 cells from type II to type I. Collectively, these results suggest that the type I/type II dichotomy reflects differences in cell surface death receptor expression. PMID:21865165

  9. Transfer of Fas (CD95 protein from the cell surface to the surface of polystyrene beads coated with anti-Fas antibody clone CH-11

    Directory of Open Access Journals (Sweden)

    H. Sawai

    2010-02-01

    Full Text Available Mouse monoclonal anti-Fas (CD95 antibody clone CH-11 has been widely used in research on apoptosis. CH-11 has the ability to bind to Fas protein on cell surface and induce apoptosis. Here, we used polystyrene beads coated with CH-11 to investigate the role of lipid rafts in Fas-mediated apoptosis in SKW6.4 cells. Unexpectedly, by treatment of the cells with CH-11-coated beads Fas protein was detached from cell surface and transferred to the surface of CH-11-coated beads. Western blot analysis showed that Fas protein containing both extracellular and intracellular domains was attached to the beads. Fas protein was not transferred from the cells to the surface of the beads coated with other anti-Fas antibodies or Fas ligand. Similar phenomenon was observed in Jurkat T cells. Furthermore, CH-11-induced apoptosis was suppressed by pretreatment with CH-11-coated beads in Jurkat cells. These results suggest that CH-11 might possess distinct properties on Fas protein compared with other anti-Fas antibodies or Fas ligand, and also suggest that caution should be needed to use polystyrene beads coated with antibodies such as CH-11.

  10. Investigation of integrin expression on the surface of osteoblast-like cells by atomic force microscopy

    International Nuclear Information System (INIS)

    The transforming growth factor β1 (TGF-β1) is a human cytokine which has been demonstrated to modulate cell surface integrin repertoire. In this work integrin expression in response to TGF-β1 stimulation has been investigated on the surface of human osteoblast-like cells. We used atomic force microscopy (AFM) and confocal laser scanning microscopy to assess integrin expression and to evaluate their distribution over the dorsal side of the plasma membrane. AFM probes have been covalently functionalised with monoclonal antibodies specific to the β1 integrin subunit. Force curves have been collected in order to obtain maps of the interaction between the immobilized antibody and the respective cell membrane receptors. Adhesion peaks have been automatically detected by means of an ad hoc developed data analysis software. The specificity of the detected interactions has been assessed by adding free antibody in the solution and monitoring the dramatic decrease in the recorded interactions. In addition, the effect of TGF-β1 treatment on both the fluorescence signal and the adhesion events has been tested. The level of expression of the β1 integrin subunit was enhanced by TGF-β1. As a further analysis, the adhesion force of the single living cells to the substrate was measured by laterally pushing the cell with the AFM tip and measuring the force necessary to displace it. The treatment with TGF-β1 resulted in a decrease of the cell/substrate adhesion force. Results obtained by AFM have been validated by confocal laser scanning microscopy thus demonstrating the high potential of the AFM technique for the investigation of cell surface receptors distribution and trafficking at the nanoscale.

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

    Science.gov (United States)

    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

  12. Curcumin induced nanoscale CD44 molecular redistribution and antigen-antibody interaction on HepG2 cell surface

    Energy Technology Data Exchange (ETDEWEB)

    Wang Mu [Department of Chemistry, Jinan University, 601 Huangpu Road West, Tianhe District, Guangzhou 510632 (China); Ruan Yuxia [Department of Ophthalmology, The First Affiliated Hospital, Jinan University, 601 Huangpu Road West, Tianhe District, Guangzhou 510632 (China); Xing Xiaobo; Chen Qian; Peng, Yuan [Department of Chemistry, Jinan University, 601 Huangpu Road West, Tianhe District, Guangzhou 510632 (China); Cai Jiye, E-mail: tjycai@jnu.edu.cn [Department of Chemistry, Jinan University, 601 Huangpu Road West, Tianhe District, Guangzhou 510632 (China)

    2011-07-04

    Graphical abstract: Highlights: > In this study, we investigate the changes of CD44 expression and distribution on HepG2 cells after curcumin treatment. > We find curcumin is able to change the morphology and ultrastructure of HepG2 cells. > Curcumin can reduce the expression of CD44 molecules and induce the nanoscale molecular redistribution on cell surface. > The binding force between CD44-modified AFM tip and the HepG2 cell surface decreases after curcumin-treatment. - Abstract: The cell surface glycoprotein CD44 was implicated in the progression, metastasis and apoptosis of certain human tumors. In this study, we used atomic force microscope (AFM) to monitor the effect of curcumin on human hepatocellular carcinoma (HepG2) cell surface nanoscale structure. High-resolution imaging revealed that cell morphology and ultrastructure changed a lot after being treated with curcumin. The membrane average roughness increased (10.88 {+-} 4.62 nm to 129.70 {+-} 43.72 nm) and the expression of CD44 decreased (99.79 {+-} 0.16% to 75.14 {+-} 8.37%). Laser scanning confocal microscope (LSCM) imaging showed that CD44 molecules were located on the cell membrane. The florescence intensity in control group was weaker than that in curcumin treated cells. Most of the binding forces between CD44 antibodies and untreated HepG2 cell membrane were around 120-220 pN. After being incubated with curcumin, the major forces focused on 70-150 pN (10 {mu}M curcumin-treated) and 50-120 pN (20 {mu}M curcumin-treated). These results suggested that, as result of nanoscale molecular redistribution, changes of the cell surface were in response to external treatment of curcumin. The combination of AFM and LSCM could be a powerful method to detect the distribution of cell surface molecules and interactions between molecules and their ligands.

  13. MC3T3-E1 Cells on Titanium Surfaces with Nanometer Smoothness and Fibronectin Immobilization

    Directory of Open Access Journals (Sweden)

    Tohru Hayakawa

    2012-01-01

    Full Text Available The present study was aimed to evaluate the viability and total protein contents of osteoblast-like cells on the titanium surface with different surface mechanical treatment, namely, nanometer smoothing (Ra: approximately 2.0 nm and sandblasting (Ra: approximately 1.0 μm, and biochemical treatment, namely, with or without fibronectin immobilization. Fibronectin could be easily immobilized by tresyl chloride-activation technique. MC3T3-E1 cells were seeded on the different titanium surfaces. Cell viability was determined by MTT assay. At 1 day of cell culture, there were no significant differences in cell viability among four different titanium surfaces. At 11 days, sandblasted titanium surface with fibronectin immobilization showed the significantly highest cell viability than other titanium surface. No significant differences existed for total protein contents among four different titanium surfaces at 11 days of cell culture. Scanning electron microscopy observation revealed that smoothness of titanium surface produced more spread cell morphologies, but that fibronectin immobilization did not cause any changes of the morphologies of attached cells. Fibronectin immobilization provided greater amount of the number of attached cells and better arrangement of attached cells. In conclusion, the combination of sandblasting and fibronectin immobilization enhanced the cell viability and fibronectin immobilization providing better arrangements of attached cells.

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

    Directory of Open Access Journals (Sweden)

    Alexander Röder

    2015-11-01

    Full Text Available 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.

  15. Human MHC class I antigens are associated with a 90-kDa cell surface protein.

    Science.gov (United States)

    Ferm, M T; Grönberg, A

    1991-08-01

    Human MHC class I proteins are expressed on almost all nucleated cells as a heavy chain (about 45 kDa) non-covalently associated with beta 2-microglobulin (12 kDa). In this report we show that MHC class I (MHC-I) proteins can also be associated with a 90-kDa protein in the cell membrane. Surface-radiolabelled cells were treated with dithiobis succinimidyl propionate (DSP) in order to preserve multimer protein complexes during cell lysis. The lysates were immunoprecipitated and analysed by SDS-PAGE and autoradiography. Immunoprecipitation of human MHC-I proteins co-precipitated another protein of about 90 kDa in molecular weight-p90. p90 was coprecipitated from all the MHC-I expressing cells tested: U937, Raji, Molt-4 and IFN-gamma treated K562, but not from untreated, MHC-I negative K562. A 90-kDa protein was also co-precipitated with MHC-I from fresh peripheral blood mononuclear cells (PBMC). Furthermore, p90 was coprecipitated by different MoAbs to the MHC-I heavy chain or beta 2-microglobulin, but not by control antibodies. Two additional co-precipitating proteins at 34 kDa and 28 kDa were seen in MHC-I precipitates from Raji cells. Our results suggest that MHC-I proteins and the 90-kDa protein are associated in the cell membrane, probably by a close but weak, non-covalent interaction. Two additional cell surface proteins at 34 kDa and 28 kDa seem to be MHC-I associated on Raji Burkitt's lymphoma cells.

  16. Phorbol-induced surface expression of NR2A subunit homologues in HEK293 cells

    Institute of Scientific and Technical Information of China (English)

    Chan-ying ZHENG; Xiu-juan YANG; Zhan-yan FU; Jian-hong LUO

    2006-01-01

    Aim: N-methyl-D-aspartate receptors (NMDAR) are heteromeric complexes primarily assembled from NR1 and NR2 subunits. In normal conditions, NR2 sub-units assemble into homodimers in the endoplasmic reticulum (ER). These homodimers remain in the ER until they coassemble with NR1 dimers and are trafficked to the cell surface. However, it still remains unclear whether functional homomeric NMDAR exist in physiological or pathological conditions. Methods: We transfected GFP-NR2A alone into HEK293 cells, treated the cells with PKC activator 12-myristate-13 acetate (PMA), and then detected surface NR2A sub-units with a live cell immunostaining method. We also used a series of NR2A mutants with a partial deletion of its C-terminus to identify the regions that are involved in the PMA-mediated surface expression of NR2A subunits. Results: NR2A subunits were expressed on the cell membrane after incubation with PMA (200 nmol/L,30 min), although no functional NMDA channels were detected after PMA-induced membrane trafficking. Immunostaining with an ER marker also revealed that NR2A subunits were exported from the ER after PMA treatment. Furthermore, the deletion of amino acids between 1149-1347 or 1354-1464 of NR2A inhibited PMA-induced surface expression of NR2A subunits. Conclusion: First, our data suggests that PMA treatment can induce the surface expression of homomeric NR2A subunits. Furthermore, this process is probably mediated by the NR2A C-terminal region between positions 1149 and 1464.

  17. Cell adhesion on Ti surface with controlled roughness

    Directory of Open Access Journals (Sweden)

    Burgos-Asperilla, Laura

    2015-06-01

    Full Text Available In this report, the in situ interaction between Saos-2 osteoblast cells and a smooth Ti surface was examined over time. The adhesion kinetics and mechanisms of cellular proliferation were monitored by quartz crystal microbalance (QCM and electrochemical impedance spectroscopy (EIS. The rate of Saos-2 attachment on Ti surfaces, obtained from the measurements performed with the QCM, is a first-order reaction, with k=2.10−3 min−1. The impedance measurements indicate that in the absence of cells, the Ti resistance diminishes over time (7 days, due to the presence of amino acids and proteins from the culture medium that have been a dsorbed, while in the presence of osteoblasts, this decrease is much greater because of the compounds generated by the cells that accelerate the dissolution of Ti.En este trabajo, se ha estudiado la interacción in situ entre células osteoblásticas Saos-2 y una superficie de Ti de rugosidad controlada a lo largo del tiempo. El estudio de la cinética y los mecanismos de proliferación celular de adhesión se ha realizado a través de la microbalanza de cristal de cuarzo (QCM y espectroscopía de impedancia electroquímica (EIS. La velocidad de adhesión de los osteoblastos sobre la superficie de Ti obtenida a través de medidas con la QCM, sigue una reacción de primer orden, con k=2×10−3 min−1. Los ensayos de impedancia indican que, en ausencia de las células, la resistencia del Ti disminuye con el tiempo (7 días, debido a la presencia de aminoácidos y proteínas del medio de cultivo que se han adsorbido, mientras que en presencia de células, esta disminución es mucho mayor debido a los productos metabólicos generados por las células que aceleran la disolución del Ti.

  18. Dye-Sensitized Solar Cells Based on High Surface Area Nanocrystalline Zinc Oxide Spheres

    Directory of Open Access Journals (Sweden)

    Pavuluri Srinivasu

    2011-01-01

    Full Text Available High surface area nanocrystalline zinc oxide material is fabricated using mesoporous nanostructured carbon as a sacrificial template through combustion process. The resulting material is characterized by XRD, N2 adsorption, HR-SEM, and HR-TEM. The nitrogen adsorption measurement indicates that the materials possess BET specific surface area ca. 30 m2/g. Electron microscopy images prove that the zinc oxide spheres possess particle size in the range of 0.12 μm–0.17 μm. The nanocrystalline zinc oxide spheres show 1.0% of energy conversion efficiency for dye-sensitized solar cells.

  19. Ground surface temperature scenarios in complex high-mountain topography based on regional climate model results

    Science.gov (United States)

    Salzmann, Nadine; NöTzli, Jeannette; Hauck, Christian; Gruber, Stephan; Hoelzle, Martin; Haeberli, Wilfried

    2007-06-01

    Climate change can have severe impacts on the high-mountain cryosphere, such as instabilities in rock walls induced by thawing permafrost. Relating climate change scenarios produced from global climate models (GCMs) and regional climate models (RCMs) to complex high-mountain environments is a challenging task. The qualitative and quantitative impact of changes in climatic conditions on local to microscale ground surface temperature (GST) and the ground thermal regime is not readily apparent. This study assesses a possible range of changes in the GST (ΔGST) in complex mountain topography. To account for uncertainties associated with RCM output, a set of 12 different scenario climate time series (including 10 RCM-based and 2 incremental scenarios) was applied to the topography and energy balance (TEBAL) model to simulate average ΔGST for 36 different topographic situations. Variability of the simulated ΔGST is related primarily to the emission scenarios, the RCM, and the approach used to apply RCM results to the impact model. In terms of topography, significant influence on GST simulation was shown by aspect because it modifies the received amount of solar radiation at the surface. North faces showed higher sensitivity to the applied climate scenarios, while uncertainties are higher for south faces. On the basis of the results of this study, use of RCM-based scenarios is recommended for mountain permafrost impact studies, as opposed to incremental scenarios.

  20. Cell-surface expression of Hsp70 on hematopoietic cancer cells after inhibition of HDAC activity

    DEFF Research Database (Denmark)

    Jensen, Helle

    The function of Hsp70 depends on its cellular location: When located intracellularly it exerts cytoprotective and anti-apoptotic functions, whereas it exerts immunostimulatory functions when located extracellularly. Secreted Hsp70 is for example involved in cross-presentation of cancer-derived an......The function of Hsp70 depends on its cellular location: When located intracellularly it exerts cytoprotective and anti-apoptotic functions, whereas it exerts immunostimulatory functions when located extracellularly. Secreted Hsp70 is for example involved in cross-presentation of cancer......-derived antigenic peptides, a function which is currently explored in immunotherapeutic approaches against cancer. Additionally, membrane-bound Hsp70 can stimulate antigen presenting cells to release proinflammatory cytokines and can provide a target structure for NK cell-mediated lysis. Human cancer cells...... frequently express Hsp70 on their cell surface, whereas the corresponding normal tissues do not. In addition, several clinically applied reagents, such as alkyl-lysophospholipides, chemotherapeutic agents, and anti-inflammatory reagents, have been found to enhance Hsp70 cell surface expression on cancer...

  1. Targeting glucosylceramide synthase induction of cell surface globotriaosylceramide (Gb3) in acquired cisplatin-resistance of lung cancer and malignant pleural mesothelioma cells

    International Nuclear Information System (INIS)

    Background: Acquired resistance to cisplatin treatment is a caveat when treating patients with non-small cell lung cancer (NSCLC) and malignant pleural mesothelioma (MPM). Ceramide increases in response to chemotherapy, leading to proliferation arrest and apoptosis. However, a tumour stress activation of glucosylceramide synthase (GCS) follows to eliminate ceramide by formation of glycosphingolipids (GSLs) such as globotriaosylceramide (Gb3), the functional receptor of verotoxin-1. Ceramide elimination enhances cell proliferation and apoptosis blockade, thus stimulating tumor progression. GSLs transactivate multidrug resistance 1/P-glycoprotein (MDR1) and multidrug resistance-associated protein 1 (MRP1) expression which further prevents ceramide accumulation and stimulates drug efflux. We investigated the expression of Gb3, MDR1 and MRP1 in NSCLC and MPM cells with acquired cisplatin resistance, and if GCS activity or MDR1 pump inhibitors would reduce their expression and reverse cisplatin-resistance. Methods: Cell surface expression of Gb3, MDR1 and MRP1 and intracellular expression of MDR1 and MRP1 was analyzed by flow cytometry and confocal microscopy on P31 MPM and H1299 NSCLC cells and subline cells with acquired cisplatin resistance. The effect of GCS inhibitor PPMP and MDR1 pump inhibitor cyclosporin A for 72 h on expression and cisplatin cytotoxicity was tested. Results: The cisplatin-resistant cells expressed increased cell surface Gb3. Cell surface Gb3 expression of resistant cells was annihilated by PPMP whereas cyclosporin A decreased Gb3 and MDR1 expression in H1299 cells. No decrease of MDR1 by PPMP was noted in using flow cytometry, whereas a decrease of MDR1 in H1299 and H1299res was indicated with confocal microscopy. No certain co-localization of Gb3 and MDR1 was noted. PPMP, but not cyclosporin A, potentiated cisplatin cytotoxicity in all cells. Conclusions: Cell surface Gb3 expression is a likely tumour biomarker for acquired cisplatin

  2. Targeting glucosylceramide synthase induction of cell surface globotriaosylceramide (Gb3) in acquired cisplatin-resistance of lung cancer and malignant pleural mesothelioma cells

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, Andreas, E-mail: andreas.tyler@medbio.umu.se [Department of Medical Biosciences, Umeå University, S-901 85 Umea (Sweden); Johansson, Anders [Department of Odontology, Umeå University, S-901 85 Umea (Sweden); Karlsson, Terese [Department of Radiation Sciences, Oncology, S-901 85 Umea (Sweden); Gudey, Shyam Kumar; Brännström, Thomas; Grankvist, Kjell; Behnam-Motlagh, Parviz [Department of Medical Biosciences, Umeå University, S-901 85 Umea (Sweden)

    2015-08-01

    Background: Acquired resistance to cisplatin treatment is a caveat when treating patients with non-small cell lung cancer (NSCLC) and malignant pleural mesothelioma (MPM). Ceramide increases in response to chemotherapy, leading to proliferation arrest and apoptosis. However, a tumour stress activation of glucosylceramide synthase (GCS) follows to eliminate ceramide by formation of glycosphingolipids (GSLs) such as globotriaosylceramide (Gb3), the functional receptor of verotoxin-1. Ceramide elimination enhances cell proliferation and apoptosis blockade, thus stimulating tumor progression. GSLs transactivate multidrug resistance 1/P-glycoprotein (MDR1) and multidrug resistance-associated protein 1 (MRP1) expression which further prevents ceramide accumulation and stimulates drug efflux. We investigated the expression of Gb3, MDR1 and MRP1 in NSCLC and MPM cells with acquired cisplatin resistance, and if GCS activity or MDR1 pump inhibitors would reduce their expression and reverse cisplatin-resistance. Methods: Cell surface expression of Gb3, MDR1 and MRP1 and intracellular expression of MDR1 and MRP1 was analyzed by flow cytometry and confocal microscopy on P31 MPM and H1299 NSCLC cells and subline cells with acquired cisplatin resistance. The effect of GCS inhibitor PPMP and MDR1 pump inhibitor cyclosporin A for 72 h on expression and cisplatin cytotoxicity was tested. Results: The cisplatin-resistant cells expressed increased cell surface Gb3. Cell surface Gb3 expression of resistant cells was annihilated by PPMP whereas cyclosporin A decreased Gb3 and MDR1 expression in H1299 cells. No decrease of MDR1 by PPMP was noted in using flow cytometry, whereas a decrease of MDR1 in H1299 and H1299res was indicated with confocal microscopy. No certain co-localization of Gb3 and MDR1 was noted. PPMP, but not cyclosporin A, potentiated cisplatin cytotoxicity in all cells. Conclusions: Cell surface Gb3 expression is a likely tumour biomarker for acquired cisplatin

  3. Results of radiation therapy for squamous cell carcinoma of vulva

    Energy Technology Data Exchange (ETDEWEB)

    Tsukiyama, Iwao; Kakehi, Masae; Ono, Ryosuke (National Cancer Center, Tokyo (Japan). Hospital)

    1984-04-01

    From 1962 to 1982, 20 cases of patients with squamous cell carcinoma of the vulva were treated by radiation alone at National Cancer Center Hospital, Tokyo. 80% (16/20) of these cases were over 60 years old. Treatment was made by interstitial irradiation (Radium needle or Au-Grain) and external irradiation (Betatron electron or Linac X-rays), alone or with various combinations. As for the stage of these cases, Stage I was 3 cases (15%), Stage II was 5 (25%) and Stage III was 12 (60%). Serious complications after treatment were observed in 15% (3/20) and all cases were treated with external irradiation alone. The 5 year survival rates by stage were as follows; Stage I 100% (3/3), Stage II 50% (2/4) and Stage III 22.2% (2/9). Surgery is considered the treatment of choice in this disease. However, radiation therapy may be indicated when the tumor has extended beyond the limit of surgical resections; when distant metastases are present; when the patient's general condition precludes surgery, or when surgery is refused.

  4. Results of radiation therapy for squamous cell carcinoma of vulva

    International Nuclear Information System (INIS)

    From 1962 to 1982, 20 cases of patients with squamous cell carcinoma of the vulva were treated by radiation alone at National Cancer Center Hospital, Tokyo. 80% (16/20) of these cases were over 60 years old. Treatment was made by interstitial irradiation (Radium needle or Au-Grain) and external irradiation (Betatron electron or Linac X-rays), alone or with various combinations. As for the stage of these cases, Stage I was 3 cases (15%), Stage II was 5 (25%) and Stage III was 12 (60%). Serious complications after treatment were observed in 15% (3/20) and all cases were treated with external irradiation alone. The 5 year survival rates by stage were as follows; Stage I 100% (3/3), Stage II 50% (2/4) and Stage III 22.2% (2/9). Surgery is considered the treatment of choice in this disease. However, radiation therapy may be indicated when the tumor has extended beyond the limit of surgical resections; when distant metastases are present; when the patient's general condition precludes surgery, or when surgery is refused. (author)

  5. HIV-1 infection leads to increased HLA-E expression resulting in impaired function of natural killer cells.

    Science.gov (United States)

    Nattermann, Jacob; Nischalke, Hans Dieter; Hofmeister, Valesko; Kupfer, Bernd; Ahlenstiel, Golo; Feldmann, Georg; Rockstroh, Jiirgen; Weiss, Elisabeth H; Sauerbruch, Tilman; Spengler, Ulrich

    2005-01-01

    HIV has evolved several strategies to evade recognition by the host immune system including down-regulation of major histocompatibility complex (MHC) class I molecules. However, reduced expression of MHC class I molecules may stimulate natural killer (NK) cell lysis in cells of haematopoietic lineage. Here, we describe how HIV counteracts stimulation of NK cells by stabilizing surface expression of the non-classical MHC class I molecule, HLA-E. We demonstrate enhanced expression of HLA-E on lymphocytes from HIV-infected patients and show that in vitro infection of lymphocytes with HIV results in up-regulation of HLA-E expression and reduced susceptibility to NK cell cytotoxicity. Using HLA-E transfected K-562 cells, we identified the well-known HIV T-cell epitope p24 aa14-22a as a ligand for HLA-E that stabilizes surface expression of HLA-E, favouring inhibition of NK cell cytotoxicity. These results propose HIV-mediated up-regulation of HLA-E expression as an additional evasion strategy targeting the antiviral activities of NK cells, which may contribute to the capability of the virus in establishing chronic infection. PMID:15751767

  6. High surface area graphite as alternative support for proton exchange membrane fuel cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira-Aparicio, P.; Folgado, M.A. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, E-28040 Madrid (Spain); Daza, L. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, E-28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie, 2 Campus de Cantoblanco, E-28049 Madrid (Spain)

    2009-07-01

    The suitability of a high surface area graphite (HSAG) as proton exchange membrane fuel cell (PEMFC) catalyst support has been evaluated and compared with that of the most popular carbon black: the Vulcan XC72. It has been observed that Pt is arranged on the graphite surface resulting in different structures which depend on the catalysts synthesis conditions. The influence that the metal particle size and the metal-support interaction exert on the catalysts degradation rate is analyzed. Temperature programmed oxidation (TPO) under oxygen containing streams has been shown to be a useful method to assess the resistance of PEMFC catalysts to carbon corrosion. The synthesized Pt/HSAG catalysts have been evaluated in single cell tests in the cathode catalytic layer. The obtained results show that HSAG can be a promising alternative to the traditionally used Vulcan XC72 carbon black when suitable catalysts synthesis conditions are used. (author)

  7. Co-culture of vascular endothelial cells and smooth muscle cells by hyaluronic acid micro-pattern on titanium surface

    Science.gov (United States)

    Li, Jingan; Li, Guicai; Zhang, Kun; Liao, Yuzhen; Yang, Ping; Maitz, Manfred F.; Huang, Nan

    2013-05-01

    Micro-patterning as an effective bio-modification technique is increasingly used in the development of biomaterials with superior mechanical and biological properties. However, as of now, little is known about the simultaneous regulation of endothelial cells (EC) and smooth muscle cells (SMC) by cardiovascular implants. In this study, a co-culture system of EC and SMC was built on titanium surface by the high molecular weight hyaluronic acid (HMW-HA) micro-pattern. Firstly, the micro-pattern sample with a geometry of 25 μm wide HMW-HA ridges, and 25 μm alkali-activated Ti grooves was prepared by microtransfer molding (μTM) for regulating SMC morphology. Secondly, hyaluronidase was used to decompose high molecular weight hyaluronic acid into low molecular weight hyaluronic acid which could promote EC adhesion. Finally, the morphology of the adherent EC was elongated by the SMC micro-pattern. The surface morphology of the patterned Ti was imaged by SEM. The existence of high molecular weight hyaluronic acid on the modified Ti surface was demonstrated by FTIR. The SMC micro-pattern and EC/SMC co-culture system were characterized by immunofluorescence microscopy. The nitric oxide release test and cell retention calculation were used to evaluate EC function on inhibiting hyperplasia and cell shedding, respectively. The results indicate that EC in EC/SMC co-culture system displayed a higher NO release and cell retention compared with EC cultured alone. It can be suggested that the EC/SMC co-culture system possessed superiority to EC cultured alone in inhibiting hyperplasia and cell shedding at least in a short time of 24 h.

  8. X-ray photoelectron spectroscopy for the study of microbial cell surfaces

    NARCIS (Netherlands)

    van der Mei, Henderina C; de Vries, Jacob; Busscher, Hendrik J

    2000-01-01

    X-ray photoelectron spectroscopy (XPS) is well known for the characterisation of material surfaces, but at first glance, is an unexpected technique to study the composition of microbial cell surfaces. Despite the fact that intimate contact between materials and microbial cell surfaces occurs in many

  9. Surface Grafted Glycopolymer Brushes to Enhance Selective Adhesion of HepG2 Cells

    DEFF Research Database (Denmark)

    Chernyy, Sergey; Jensen, Bettina Elisabeth Brøgger; Shimizu, Kyoko;

    2013-01-01

    of the cell periphery. On the other hand the cells on bare glass substrate display spheroid morphology. Further analysis using ToF-SIMS imaging shows that the HepG2 cells on glycopolymer surfaces is enriched with protein fragment along the cell periphery which is absent in the case of cells on bare glass...

  10. Surface elevation changes of the greenland ice sheet - results from ESA'S ice sheet CCI

    DEFF Research Database (Denmark)

    Fredenslund Levinsen, Joanna; Khvorostovky, Kirill; Meister, Rakia;

    2013-01-01

    In order to ensure long-term climate data records for the Greenland Ice Sheet (GIS), ESA have launched the Climate Change Initiative (CCI). This work presents the preliminary steps towards the Ice Sheet CCI's surface elevation change (SEC) derivation using radar altimeter data. In order to find the...... most optimal method, a Round Robin exercise was conducted in which the scientific community was asked to provide their best SEC estimate over the Jakobshavn Isbr drainage basin. The participants used both repeat-track (RT), overlapping footprints, and the cross-over (XO) methods, and both ICESat laser...... and Envisat radar altimeter data were used. Based on this and feedback sheets describing their methods we found that a combination of the RT and XO techniques yielded the best results. In the following, the obtained results will be presented and discussed....

  11. Summary of Near-Surface Test Facility results and their application to repository design

    Science.gov (United States)

    Gregory, E. C.; Cramer, M. L.; McCabe, W. M.; Kim, K.

    1982-09-01

    Results from ongoing and newly initiated tests at the Near-Surface Test Facility contributed substantially to the store of knowledge of rock mass characterization of basalt at a variety of temperatures. Enhancements in monitoring instrumentation and testing techniques were achieved. These developments assisted in the determination of site suitability of Hanford basalt formations and contributed to refinement of predictive numerical models for use in repository design. Most recently, the testing program resulted in the following: an improved method of determining thermal expansion effects on the borehole deformation gage; an improved method of monitoring the stress relief process during the doorstopper overcoring process; and the development of a high-resolution optical device for monitoring rock mass deformation in several directions simultaneously.

  12. Modeling bispecific monoclonal antibody interaction with two cell membrane targets indicates the importance of surface diffusion.

    Science.gov (United States)

    Sengers, Bram G; McGinty, Sean; Nouri, Fatma Z; Argungu, Maryam; Hawkins, Emma; Hadji, Aymen; Weber, Andrew; Taylor, Adam; Sepp, Armin

    2016-07-01

    We have developed a mathematical framework for describing a bispecific monoclonal antibody interaction with two independent membrane-bound targets that are expressed on the same cell surface. The bispecific antibody in solution binds either of the two targets first, and then cross-links with the second one while on the cell surface, subject to rate-limiting lateral diffusion step within the lifetime of the monovalently engaged antibody-antigen complex. At experimental densities, only a small fraction of the free targets is expected to lie within the reach of the antibody binding sites at any time. Using ordinary differential equation and Monte Carlo simulation-based models, we validated this approach against an independently published anti-CD4/CD70 DuetMab experimental data set. As a result of dimensional reduction, the cell surface reaction is expected to be so rapid that, in agreement with the experimental data, no monovalently bound bispecific antibody binary complexes accumulate until cross-linking is complete. The dissociation of the bispecific antibody from the ternary cross-linked complex is expected to be significantly slower than that from either of the monovalently bound variants. We estimate that the effective affinity of the bivalently bound bispecific antibody is enhanced for about 4 orders of magnitude over that of the monovalently bound species. This avidity enhancement allows for the highly specific binding of anti-CD4/CD70 DuetMab to the cells that are positive for both target antigens over those that express only one or the other We suggest that the lateral diffusion of target antigens in the cell membrane also plays a key role in the avidity effect of natural antibodies and other bivalent ligands in their interactions with their respective cell surface receptors. PMID:27097222

  13. The topology of plasminogen binding and activation on the surface of human breast cancer cells

    OpenAIRE

    Andronicos, N M; Ranson, M.

    2001-01-01

    The urokinase-dependent activation of plasminogen by breast cancer cells plays an important role in metastasis. We have previously shown that the metastatic breast cancer cell line MDA-MB-231 over-expresses urokinase and binds and efficiently activates plasminogen at the cell surface compared to non-metastatic cells. The aim of this study was to further characterise plasminogen binding and determine the topology of cell surface-bound plasminogen in terms of its potential for activation. The l...

  14. Surface modification of PVDF using non-mammalian sources of collagen for enhancement of endothelial cell functionality

    OpenAIRE

    Wang, Jun Kit; Xiong, Gordon Minru; Luo, Baiwen; Choo, Chee Chong; Yuan, Shaojun; Tan, Nguan Soon; Choong, Cleo

    2016-01-01

    Although polyvinylidene fluoride (PVDF) is non-toxic and stable in vivo, its hydrophobic surface has limited its bio-applications due to poor cell-material interaction and thrombus formation when used in blood contacting devices. In this study, surface modification of PVDF using naturally derived non-mammalian collagen was accomplished via direct surface-initiated atom transfer radical polymerisation (SI-ATRP) to enhance its cytocompatibility and hemocompatibility. Results showed that Type I ...

  15. Electrophysical characteristics of Azospirillum brasilense Sp245 during interaction with antibodies to various cell surface epitopes.

    Science.gov (United States)

    Guliy, Olga I; Matora, Larisa Y; Burygin, Gennady L; Dykman, Lev A; Ostudin, Nikolai A; Bunin, Viktor D; Ignatov, Vladimir V; Ignatov, Oleg V

    2007-11-15

    This work was undertaken to examine the electrooptical characteristics of cells of Azospirillum brasilense Sp245 during their interaction with antibodies developed to various cell surface epitopes. We used the dependences of the cell suspension optical density changes induced by electroorientation on the orienting field frequency (740, 1000, 1450, 2000, and 2800kHz). Cell interactions with homologous strain-specific antibodies to the A. brasilense Sp245 O antigen and with homologous antibodies to whole bacterial cells brought about considerable changes in the electrooptical properties of the bacterial suspension. When genus-specific antibodies to the flagellin of the Azospirillum sheathed flagellum and antibodies to the serologically distinct O antigen of A. brasilense Sp7 were included in the A. brasilense Sp245 suspension, the changes caused in the electrooptical signal were slight and had values close to those for the above changes. These findings agree well with the immunochemical characteristics of the Azospirillum O antigens and with the data on the topographical distribution of the Azospirillum major cell surface antigens. The obtained results can serve as a basis for the development of a rapid test for the intraspecies detection of microorganisms.

  16. Bone Formation from Porcine Dental Germ Stem Cells on Surface Modified Polybutylene Succinate Scaffolds

    Directory of Open Access Journals (Sweden)

    Nergis Abay

    2016-01-01

    Full Text Available Designing and providing a scaffold are very important for the cells in tissue engineering. Polybutylene succinate (PBS has high potential as a scaffold for bone regeneration due to its capacity in cell proliferation and differentiation. Also, stem cells from 3rd molar tooth germs were favoured in this study due to their developmentally and replicatively immature nature. In this study, porcine dental germ stem cells (pDGSCs seeded PBS scaffolds were used to investigate the effects of surface modification with fibronectin or laminin on these scaffolds to improve cell attachment, proliferation, and osteogenic differentiation for tissue engineering applications. The osteogenic potentials of pDGSCs on these modified and unmodified foams were examined to heal bone defects and the effects of fibronectin or laminin modified PBS scaffolds on pDGSC differentiation into bone were compared for the first time. For this study, MTS assay was used to assess the cytotoxic effects of modified and unmodified surfaces. For the characterization of pDGSCs, flow cytometry analysis was carried out. Besides, alkaline phosphatase (ALP assay, von Kossa staining, real-time PCR, CM-Dil, and immunostaining were applied to analyze osteogenic potentials of pDGSCs. The results of these studies demonstrated that pDGSCs were differentiated into osteogenic cells on fibronectin modified PBS foams better than those on unmodified and laminin modified PBS foams.

  17. Accelerator Analysis of Tributyltin Adsorbed onto the Surface of a Tributyltin Resistant Marine Pseudoalteromonas sp. Cell

    Directory of Open Access Journals (Sweden)

    Akira Kitamura

    2008-10-01

    Full Text Available Tributyltin (TBT released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (109.3 ± 0.2 colony-forming units mL-1 adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 108.2. The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 106.8 TBT molecules is adsorbed by a single cell.

  18. Thermal surface characteristics of coal fires 1 results of in-situ measurements

    Science.gov (United States)

    Zhang, Jianzhong; Kuenzer, Claudia

    2007-12-01

    Natural underground coal fires are fires in coal seams occurring subsurface. The fires are ignited through a process named spontaneous combustion, which occurs based on a natural reaction but is usually triggered through human interaction. Coal mining activities expose coal to the air. This leads to the exothermal oxidation of the carbon in the coal with the air's oxygen to CO 2 and - under certain circumstances - to spontaneous combustion. Coal fires occur in many countries world wide - however, currently the Chinese coal mining industry faces the biggest problems with coal fires. Coal fires destroy the valuable resource coal and furthermore lead to many environmental degradation phenomena such as the deterioration of surrounding vegetation, land subsidence and the emission of toxic gasses (CO, N 2O). They additionally contribute to the emission of green house relevant gasses such as CO 2 and CH 4 to the atmosphere. In this paper we present thermal characteristics of coal fires as measured in-situ during a field campaign to the Wuda coal fire area in south-central Inner Mongolia, China. Thermal characteristics include temperature anomaly measurements at the surface, spatial surface temperature profiles of fire areas and unaffected background areas, diurnal temperature profiles, and temperature measurements inside of coal fire induced cracks in the overlying bedrock. For all the measurements the effects of uneven solar heating through influences of slope and aspect are considered. Our findings show that coal fires result in strong or subtle thermal surface anomalies. Especially the latter can easily be influenced by heating of the surrounding background material through solar influences. Temperature variation of background rocks with different albedo, slope, aspect or vegetation cover can substantially influence the detectability of thermal anomalies. In the worst case coal fire related thermal anomalies can be completely masked by solar patterns during the daytime

  19. Cell Surface Receptor Theory of Disease Infectivity; Body's Defence and Normal Body Functioning in Living Things

    Directory of Open Access Journals (Sweden)

    Utoh-Nedosa

    2011-01-01

    Full Text Available Problem statement: A study of the pattern of Candida spp. infection of the human body and the mode and pattern of reaction of the human body to this infection showed that disease infectivity and self healing by plants followed the same procedures and patterns. Approach: A comparism of these procedures and patterns of natural self- healing of disease infection by the human body and plants/plant parts with the cutaneous Candida spp. killing and elimination procedures and patterns of Vernonia amygdalina leaf extract, showed that cell surface receptors are the sites through which disease infects the body and also the sites at which the body is defended. They are also the sites where activities which result in normal body functioning are carried out. The mode and patterns of Cutaneous Candida infection in a human subject and its containment by the body was examined and photographed. The disease infection and self healing procedures and patterns of plants were also examined in comparism with those of their healthy counterparts and photographed. The findings from the observations on disease infectivity and natural body’s defence patterns and procedures of the plant parts studied and those of the human body in reaction to Candida spp. infection were compared with those of the Candida spp. killing procedures and patterns of aqueous and Arachis hypogeal oil extract of Vernonia amygdalina leaf. Results: The findings of this study also showed that disease-infective organisms gain access to the body of a host through attachment to the cell surface receptors of that host which are placed linearly and are interconnected by channels. The results of the study also indicated that living organisms have a main endogenous substance that mediates both their body’s defence and their normal physiological functioning which is therefore the owner of the cell surface receptor. Other endogenous substances which participate in normal body functioning/body’s defence or in

  20. Cell surface profiling using high-throughput flow cytometry: a platform for biomarker discovery and analysis of cellular heterogeneity.

    Directory of Open Access Journals (Sweden)

    Craig A Gedye

    Full Text Available Cell surface proteins have a wide range of biological functions, and are often used as lineage-specific markers. Antibodies that recognize cell surface antigens are widely used as research tools, diagnostic markers, and even therapeutic agents. The ability to obtain broad cell surface protein profiles would thus be of great value in a wide range of fields. There are however currently few available methods for high-throughput analysis of large numbers of cell surface proteins. We describe here a high-throughput flow cytometry (HT-FC platform for rapid analysis of 363 cell surface antigens. Here we demonstrate that HT-FC provides reproducible results, and use the platform to identify cell surface antigens that are influenced by common cell preparation methods. We show that multiple populations within complex samples such as primary tumors can be simultaneously analyzed by co-staining of cells with lineage-specific antibodies, allowing unprecedented depth of analysis of heterogeneous cell populations. Furthermore, standard informatics methods can be used to visualize, cluster and downsample HT-FC data to reveal novel signatures and biomarkers. We show that the cell surface profile provides sufficient molecular information to classify samples from different cancers and tissue types into biologically relevant clusters using unsupervised hierarchical clustering. Finally, we describe the identification of a candidate lineage marker and its subsequent validation. In summary, HT-FC combines the advantages of a high-throughput screen with a detection method that is sensitive, quantitative, highly reproducible, and allows in-depth analysis of heterogeneous samples. The use of commercially available antibodies means that high quality reagents are immediately available for follow-up studies. HT-FC has a wide range of applications, including biomarker discovery, molecular classification of cancers, or identification of novel lineage specific or stem cell

  1. Effect of cell surfaces on the stability of chiral smectic- C phases

    OpenAIRE

    VIJ, JAGDISH; Manna, Uttam; Song, Jang-Kun

    2008-01-01

    PUBLISHED The effect of surfaces on the stability of smectic-C* (SmC*) variant phases is investigated. The results obtained using dielectric spectroscopy by varying the cell thickness show that the temperature ranges of SmCalpha*, SmCA*(1/2), and SmCA*(1/3) phases decrease with decreasing cell thickness, and the SmCA*(1/3) phase is more stable than the SmCA*(1/2) phase. The relative stability of any phase is found to be due to its large polar anchoring strength and low free energy compared...

  2. Surface Engineering of ZnO Thin Film for High Efficiency Planar Perovskite Solar Cells

    OpenAIRE

    Zong-Liang Tseng; Chien-Hung Chiang; Chun-Guey Wu

    2015-01-01

    Sputtering made ZnO thin film was used as an electron-transport layer in a regular planar perovskite solar cell based on high quality CH3NH3PbI3 absorber prepared with a two-step spin-coating. An efficiency up to 15.9% under AM 1.5G irradiation is achieved for the cell based on ZnO film fabricated under Ar working gas. The atmosphere of the sputtering chamber can tune the surface electronic properties (band structure) of the resulting ZnO thin film and therefore the photovoltaic performance o...

  3. Noninvasive surface measurement of corrosion impedance of reinforcing bar in concrete - part 1: experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jieying; Monteiro, Paulo J.M.; Morrison, H. Frank

    2000-11-01

    The corrosion state of a reinforcing steel bar in concrete can be characterized by the electrical impedance of the interface between the steel bar and the concrete. The experimental part of this study, has shown that changes in the interfacial impedance that are diagnostic of the rate and extent of the corrosion can be measured indirectly with an array of current and voltage electrodes on the concrete surface. The measured impedance, however depends on the electrical resistivity of the concrete, and the depth and diameter of the steel reinforcing bar as well as the interfacial properties. To relate the measured impedance directly to the interfacial properties, a closed-form solution to the governing Poisson's equation was developed and programmed for the potentials from arbitrary, current sources in the vicinity of the reinforcing bar. The solution uses an impedance boundary, condition for the complex impedance at the steel-concrete interface. The response of an arbitrary corrosion state can be simulated in this model by embedding the appropriate complex, frequency-dependent impedance at the interface and computing the voltage/current response that would be measured for an arbitrary placement of electrodes on the concrete surface. To simulate the experimental findings, this paper presents the modeling results by various interfacial impedances but constant concrete resistivity and constant geometry of the steel reinforcing bar This simulation confirms that important parameters of the interfacial impedance controlling corrosion kinetics such as polarization resistance and double layer capacitance are clearly, observed in the measured surface data. [References: 10

  4. Analyzing model uncertainty in predicted surface fluxes resulting from prescribed soil and vegetation parameters

    Science.gov (United States)

    Jankov, M.; Prochaka, L.; Mölders, N.

    2003-12-01

    The atmosphere and land-surface continuously interact, for which the surface affects current weather and climate. The biosphere-soil system plays an important role because it is the media in those interactions. The processes that describe those interactions are the exchange of momentuum, heat, water vapor, and matter. To include these processes at the soil-biosphere-atmosphere interface in atmospheric models they have to be parameterized. The different vegetation and soil types are realized by prescribed plant physiological and soil physical parameters (e.g. soil hydraulic conductivity, soil thermal conductivity, porosity, pore-size distribution index, leaf area index, albedo and emissivity of the foliage and soil, minimum stomatal resistance, canopy height, etc.) in these parameterizations. The parameters can vary even among the same soil or plant type. The order of magnitude of those variations can be as much as the mean values of the parameters themselves. In order to improve weather prediction the model uncertainty, caused by the necessity to prescribe parameters, has to be minimized. To asses the errors uncertainty analysis with respect to the prescribed parameters is carried out using the Gaussian Error Propagation method. We use the PennState/NCAR mesoscale meteorological model MM5 coupled with the Oregon State University land surface model (OSULSM) as the test-platform. The Gaussian Error Propagation technique provides error bars for the fluxes simulated by MM5. Moreover, the technique can point out which parameters contribute the most to the error, and should be replaced in future model development. Our preliminary results show that throughout the domain errors were at low or moderate levels. The highest errors predicted appear to be associated with scarcely vegetated, sandy clay loam areas and areas covered by ice and snow.

  5. Cell surface molecules and fibronectin-mediated cell adhesion: effect of proteolytic digestion of membrane proteins

    OpenAIRE

    1982-01-01

    Proteases have been used as a tool to investigate the role of surface molecules in fibronectin-mediated cell adhesion. Proteolytic digestion of membrane-proteins by pronase (1 mg/ml for 20 min at 37 degrees C) completely inhibited adhesion of baby hamster kidney (BHK) fibroblasts on fibronectin-coated plastic dishes. Various degrees of inhibition were also obtained after treatment with proteinase K, chymotrypsin, papain, subtilopeptidase A, and thermolysin. Protein synthesis was required to r...

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

    Science.gov (United States)

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

    2015-01-13

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

  7. Coupling Binding to Catalysis – Using Yeast Cell Surface Display to Select Enzymatic Activities

    OpenAIRE

    Zhang, Keya; Bhuripanyo, Karan; Wang, Yiyang; Yin, Jun

    2015-01-01

    We find yeast cell surface display can be used to engineer enzymes by selecting the enzyme library for high affinity binding to reaction intermediates. Here we cover key steps of enzyme engineering on the yeast cell surface including library design, construction, and selection based on magnetic and fluorescence activated cell sorting.

  8. Coupling Binding to Catalysis: Using Yeast Cell Surface Display to Select Enzymatic Activities.

    Science.gov (United States)

    Zhang, Keya; Bhuripanyo, Karan; Wang, Yiyang; Yin, Jun

    2015-01-01

    We find yeast cell surface display can be used to engineer enzymes by selecting the enzyme library for high affinity binding to reaction intermediates. Here we cover key steps of enzyme engineering on the yeast cell surface including library design, construction, and selection based on magnetic and fluorescence-activated cell sorting. PMID:26060080

  9. Cell Proliferation on Macro/Nano Surface Structure and Collagen Immobilization of 3D Polycaprolactone Scaffolds.

    Science.gov (United States)

    Park, Young-Ouk; Myung, Sung-Woon; Kook, Min-Suk; Jung, Sang-Chul; Kim, Byung-Hoon

    2016-02-01

    In this study, 3D polycaprolactone (PCL) scaffolds were fabricated by 3D printing technique. The macro/nano morphology of, 3D PCL scaffolds surface was etched with oxygen plasma. Acrylic acid (AA) plasma-polymerization was performed to functionalize the macro/nano surface with carboxyl groups and then collagen was immobilized with plasma-polymerized 3D PCL scaffolds. After O2 plasma and AA plasma-polymerization, contact angles were decreased. The FE-SEM and AFM results showed that O2 plasma is increased the surface roughness. The MTT assay results showed that proliferation of the M3CT3-E1 cells increased on the oxygen plasma treated and collagen immobilized 3D PCL scaffolds. PMID:27433597

  10. ALG-2 knockdown in HeLa cells results in G2/M cell cycle phase accumulation and cell death

    DEFF Research Database (Denmark)

    Høj, Berit Rahbek; la Cour, Peter Jonas Marstrand; Mollerup, Jens;

    2009-01-01

    ALG-2 (apoptosis-linked gene-2 encoded protein) has been shown to be upregulated in a variety of human tumors questioning its previously assumed pro-apoptotic function. The aim of the present study was to obtain insights into the role of ALG-2 in human cancer cells. We show that ALG-2 downregulat......ALG-2 (apoptosis-linked gene-2 encoded protein) has been shown to be upregulated in a variety of human tumors questioning its previously assumed pro-apoptotic function. The aim of the present study was to obtain insights into the role of ALG-2 in human cancer cells. We show that ALG-2...... downregulation induces accumulation of HeLa cells in the G2/M cell cycle phase and increases the amount of early apoptotic and dead cells. Caspase inhibition by the pan-caspase inhibitor zVAD-fmk attenuated the increase in the amount of dead cells following ALG-2 downregulation. Thus, our results indicate that...

  11. Facile modification of gelatin-based microcarriers with multiporous surface and proliferative growth factors delivery to enhance cell growth

    International Nuclear Information System (INIS)

    The design of microcarriers plays an important role in the success of cell expansion. The present article provides a facile approach to modify the gelatin-based particles and investigates the feasibility of their acting as microcarriers for cell attachment and growth. Gelatin particles (150-320 μm) were modified by cryogenic treatment and lyophilization to develop the surface with the features of multiporous morphology and were incorporated with proliferative growth factors (bFGF) by adsorption during the post-preparation, which enables them to serve as microcarriers for cells amplification, together with the advantages of larger cell-surface contact area and capability of promoting cell propagation. The microstructure and release assay of the modified microcarriers demonstrated that the pores on surface were uniform and bFGF was released in a controlled manner. Through in vitro fibroblast culture, these features resulted in a prominent increase in the cell attachment rate and cell growth rate relative to the conditions without modification. Although the scanning electron microscopy and optical microscopy analysis results indicated that cells attached, spread, and proliferated on all the microcarriers, cell growth clearly showed a significant correlation with the multiporous structure of microcarriers, in particular on bFGF combined ones. These results validate our previous assumption that the facile modification could improve cell growth on the gelatin-based microcarriers obviously and the novel microcarriers may be a promising candidate in tissue engineering

  12. Facile modification of gelatin-based microcarriers with multiporous surface and proliferative growth factors delivery to enhance cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Huang Sha [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Wang Yijuan [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Deng, Tianzheng [Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Jin Fang [Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi' an, 710032 (China); Liu Shouxin [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Zhang Yongjie [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Feng Feng [Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Department of Dermatology, Tangdu Hospital, Fourth Military Medical University, Xi' an 710038 (China); Jin Yan [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China)], E-mail: yanjin@fmmu.edu.cn

    2008-07-28

    The design of microcarriers plays an important role in the success of cell expansion. The present article provides a facile approach to modify the gelatin-based particles and investigates the feasibility of their acting as microcarriers for cell attachment and growth. Gelatin particles (150-320 {mu}m) were modified by cryogenic treatment and lyophilization to develop the surface with the features of multiporous morphology and were incorporated with proliferative growth factors (bFGF) by adsorption during the post-preparation, which enables them to serve as microcarriers for cells amplification, together with the advantages of larger cell-surface contact area and capability of promoting cell propagation. The microstructure and release assay of the modified microcarriers demonstrated that the pores on surface were uniform and bFGF was released in a controlled manner. Through in vitro fibroblast culture, these features resulted in a prominent increase in the cell attachment rate and cell growth rate relative to the conditions without modification. Although the scanning electron microscopy and optical microscopy analysis results indicated that cells attached, spread, and proliferated on all the microcarriers, cell growth clearly showed a significant correlation with the multiporous structure of microcarriers, in particular on bFGF combined ones. These results validate our previous assumption that the facile modification could improve cell growth on the gelatin-based microcarriers obviously and the novel microcarriers may be a promising candidate in tissue engineering.

  13. A network of autonomous surface ozone monitors in Antarctica: technical description and first results

    Science.gov (United States)

    Bauguitte, S. J.-B.; Brough, N.; Frey, M. M.; Jones, A. E.; Maxfield, D. J.; Roscoe, H. K.; Rose, M. C.; Wolff, E. W.

    2011-04-01

    A suite of 10 autonomous ozone monitoring units, each powered using renewable energy, was developed and built to study surface ozone in Antarctica during the International Polar Year (2007-2009). The monitoring systems were deployed in a network around the Weddell Sea sector of coastal Antarctica with a transect up onto the Antarctic Plateau. The aim was to measure for a full year, thus gaining a much-improved broader view of boundary layer ozone seasonality at different locations as well as of factors affecting the budget of surface ozone in Antarctica. Ozone mixing ratios were measured based on UV photometry using a modified version of the commercial 2B Technologies Inc. Model 202 instrument. All but one of the autonomous units measured successfully within its predefined duty cycle throughout the year, with some differences in performance dependent on power availability and ambient temperature. Mean data recovery after removal of outliers was on average 70% (range 44-83%) and precision varied between 1.5 and 8 ppbv, thus was sufficiently good to resolve year-round the main ozone features of scientific interest. We conclude that, with adequate power, and noting a minor communication problem, our units would be able to operate successfully at ambient temperatures down to -60 °C. Systems such as the one described in this paper, or derivatives of it, could therefore be deployed either as local or regional networks elsewhere in the Arctic or Antarctic. Here we present technical information and first results from the experiment.

  14. Effects of 60Co γ-ray irradiation on expression of surface antigens in endothelial cells of human umbilical veins

    International Nuclear Information System (INIS)

    Culture of endothelial cells of human umbilical veins and avidin-biotin peroxidase complex (ABC) immunochemical technique were used in the experiment to detect the surface antigens in endothelial cells. Endothelial cells separated from five umbilical cords in original culture were divided into two groups, irradiated and non-irradiated. The cells were irradiated with 15 Gy of 60Co γ-rays at dose rates of 21.78 cGy/min. Then antigens RBC A, HLA-ABC, HLA-DR, CD4 and CD8 were assayed for both groups by the method of ABC. The results showed that the values of integrated optical density (IOD) for the surface antigens in the irradiated cells were lower than those in the non-irradiated cells with the difference in antigen expression in endothelial cells being significant (P<0.05) between the two groups

  15. High Gradient Results of ICHIRO 9-Cell Cavity in Collaboration With KEK and Jlab

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, F. [KEK, Tsukuba (Japan); Konomi, T. [KEK, Tsukuba (Japan); Saito, K. [KEK, Tsukuba (Japan); Eremeev, G. V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Geng, R. L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2011-07-01

    KEK and Jlab have continued S0-study collaboration on ICHIRO 9-cell cavities since 2008. In 2010, we have started S0 study on ICHIRO#7, full 9-cell cavity with end groups. Surface treatments and vertical tests have been repeated at Jlab. Maximum gradient of 40MV/m was achieved so far. We will describe the details of that and further plan of S0-study on ICHIRO 9-cell.

  16. Biocatalysis on the surface of Escherichia coli: melanin pigmentation of the cell exterior

    Science.gov (United States)

    Gustavsson, Martin; Hörnström, David; Lundh, Susanna; Belotserkovsky, Jaroslav; Larsson, Gen

    2016-01-01

    Today, it is considered state-of-the-art to engineer living organisms for various biotechnology applications. Even though this has led to numerous scientific breakthroughs, the enclosed interior of bacterial cells still restricts interactions with enzymes, pathways and products due to the mass-transfer barrier formed by the cell envelope. To promote accessibility, we propose engineering of biocatalytic reactions and subsequent product deposition directly on the bacterial surface. As a proof-of-concept, we used the AIDA autotransporter vehicle for Escherichia coli surface expression of tyrosinase and fully oxidized externally added tyrosine to the biopolymer melanin. This resulted in a color change and creation of a black cell exterior. The capture of ninety percent of a pharmaceutical wastewater pollutant followed by regeneration of the cell bound melanin matrix through a simple pH change, shows the superior function and facilitated processing provided by the surface methodology. The broad adsorption spectrum of melanin could also allow removal of other micropollutants. PMID:27782179

  17. Characterization of the aspects of osteoprogenitor cell interactions with physical tetracalcium phosphate anchorage on titanium implant surfaces

    International Nuclear Information System (INIS)

    Well-designed implants are used not only to modify the geometry of the implant but also to change the chemical properties of its surfaces. The present study aims to assess the biofunctional effects of tetracalcium phosphate (TTCP) particles as a physical anchor on the implant surface derived through sandblasting. The characteristics of the surface, cell viability, and alkaline phosphatase (ALP) activity toward osteoprogenitor cells (D1) were obtained. D1 cells were cultured on a plain surface that underwent sandblasting and acid etching (SLA) (control SLA group) and on different SLA surfaces with different anchoring TTCP rates (new test groups, M and H). The mean anchoring rates were 57% (M) and 74% (H), and the anchored thickness was estimated to range from 12.6 μm to 18.3 μm. Compared with the control SLA surface on Ti substrate, the new test groups with different TTCP anchoring rates (M and H) failed to improve cell proliferation significantly but had a well-differentiated D1 cell phenotype that enhanced ALP expression in the early stage of cell cultures, specifically, at day 7. Results suggest that the SLA surface with anchored TTCP can accelerate progenitor bone cell mineralization. This study shows the potential clinical application of the constructed geometry in TTCP anchorage on Ti for dental implant surface modification. - Highlights: • TTCP (tetracalcium phosphate) as a physical anchorage on implant is characterized. • Theoretical values of anchored thickness and capping areas were estimated. • TTCP anchored by sandblasting can accelerate progenitor bone cell mineralization. • TTCP anchored on SLA (sandblasting and acid etching) surface is a promising method

  18. Characterization of the aspects of osteoprogenitor cell interactions with physical tetracalcium phosphate anchorage on titanium implant surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Chia-Ling [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, Feng Chia University, Taichung 40724, Taiwan (China); Dental Medical Devices and Materials Research Center, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Chang, Ya-Yuan; Liou, Cian-Hua [Alliance Global Technology Co., Ltd., Kaohsiung Medical Device Special Zone in Southern Taiwan Science Park, Kaohsiung 82151, Taiwan (China); Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, Feng Chia University, Taichung 40724, Taiwan (China)

    2015-04-01

    Well-designed implants are used not only to modify the geometry of the implant but also to change the chemical properties of its surfaces. The present study aims to assess the biofunctional effects of tetracalcium phosphate (TTCP) particles as a physical anchor on the implant surface derived through sandblasting. The characteristics of the surface, cell viability, and alkaline phosphatase (ALP) activity toward osteoprogenitor cells (D1) were obtained. D1 cells were cultured on a plain surface that underwent sandblasting and acid etching (SLA) (control SLA group) and on different SLA surfaces with different anchoring TTCP rates (new test groups, M and H). The mean anchoring rates were 57% (M) and 74% (H), and the anchored thickness was estimated to range from 12.6 μm to 18.3 μm. Compared with the control SLA surface on Ti substrate, the new test groups with different TTCP anchoring rates (M and H) failed to improve cell proliferation significantly but had a well-differentiated D1 cell phenotype that enhanced ALP expression in the early stage of cell cultures, specifically, at day 7. Results suggest that the SLA surface with anchored TTCP can accelerate progenitor bone cell mineralization. This study shows the potential clinical application of the constructed geometry in TTCP anchorage on Ti for dental implant surface modification. - Highlights: • TTCP (tetracalcium phosphate) as a physical anchorage on implant is characterized. • Theoretical values of anchored thickness and capping areas were estimated. • TTCP anchored by sandblasting can accelerate progenitor bone cell mineralization. • TTCP anchored on SLA (sandblasting and acid etching) surface is a promising method.

  19. An efficient delivery of DAMPs on the cell surface by the unconventional secretion pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Haiyan; Wang, Lan; Ruan, Yuanyuan; Zhou, Lei; Zhang, Dongmei [Department of Biochemistry and Molecular Biology, Shanghai Medical Collage, Fudan University, Shanghai 200032 (China); Min, Zhihui [Biomedical Research Center, Zhongshan Hospital, Fudan University, Shanghai 200032 (China); Xie, Jianhui [Department of Biochemistry and Molecular Biology, Shanghai Medical Collage, Fudan University, Shanghai 200032 (China); Yu, Min, E-mail: minyu@shmu.edu.cn [Department of Biochemistry and Molecular Biology, Shanghai Medical Collage, Fudan University, Shanghai 200032 (China); Gu, Jianxin [Department of Biochemistry and Molecular Biology, Shanghai Medical Collage, Fudan University, Shanghai 200032 (China)

    2011-01-21

    Research highlights: {yields} Hsp60 transported to cell surface through the classical secretory pathway was modified with N-glycosylation. {yields} HSAPB-N18 could efficiently deliver Hsp60 to the cell surface via the unconventional secretory pathway. {yields} Cell surface Hsp60 delivered by HASPB-N18 has a proper conformation. {yields} HASPB-N18 is an efficient delivery signal for other DAMP molecules such as Hsp70 and HMGB1. -- Abstract: Damage-associated molecular patterns (DAMPs) are signals released from dying cells evoking the immune system response in several inflammatory disorders. In normal situations, many of DAMPs are nuclear or cytosolic proteins with defined intracellular function, but they could be found on the cell surface following tissue injury. The biological function of the translocated DAMPs is still not well known and an efficient delivery of these molecules on the cell surface is required to clarify their biological effects. In this study, we demonstrated that an unclassical secretory signal peptide, N-terminal 18 amino acids of HASPB (HASPB-N18), could efficiently deliver Hsp60, Hsp70, and HMGB1 on the cell surface. Furthermore, the delivery of these molecules on the cell surface by HASPB-N18 is not limited to a special cell line because several cell lines could use this delivery signal to deliver these molecules on the cell surface. Moreover, we demonstrated that Hsp60 on the cell surface delivered by HASPB-N18 could be recognized by a soluble form of LOX-1, which implies that DAMPs on the cell surface delivered by HASPB-N18 have a proper conformation during transport. Therefore, delivery of DAMPs by HASPB-N18 is a reliable model to further understand the biological significance of DAMPs on the cell surface.

  20. T cell responses to hepatitis B surface antigen are detectable in non-vaccinated individuals

    Institute of Scientific and Technical Information of China (English)

    Martin R Weihrauch; Michael von Bergwelt-Baildon; Milos Kandic; Martin Weskott; Winfried Klamp; Joachim R(o)sier; Joachim L Schultze

    2008-01-01

    AIM: To evaluate, whether humoral hepatitis-B-vaccine non-responders also fail to mount a T cell response and to compare these results to normal vaccinees.METHODS: Fourty-seven health care employees were enrolled in this study including all available nonresponders (n = 13) with an anti-HBsAg titer 1000 kU/L as controls.PBMC from all subjects were analyzed by IFN-γ and IL-4 ELISPOT assays for the presence of hepatitis B surface antigen (HBsAg) reactive T cells.RESULTS: Non-responders and low-responders had no or only very limited T cell responses, respectively.Individuals responding to vaccination with the induction of a high anti-HBsAg titer showed a strong T cell response after the third vaccination.Surprisingly, these individuals showed response even before the first vaccination.T cell response to control antigens and mitogens was similar in all groups.CONCLUSION: Our data suggest that there is no general immune deficiency in non-/low-responders.Thus,we hypothesize that the induction of anti-HBsAg responses by vaccination is significantly dependent on the pre-existing T cell repertoire against the specific antigen rather than the presence of a general T cell defect.

  1. Comparative evaluation of the three different surface treatments - conventional, laser and Nano technology methods in enhancing the surface characteristics of commercially pure titanium discs and their effects on cell adhesion: An in vitro study.

    Science.gov (United States)

    Vignesh; Nayar, Sanjna; Bhuminathan; Mahadevan; Santhosh, S

    2015-04-01

    The surface area of the titanium dental implant materials can be increased by surface treatments without altering their shape and form, thereby increasing the biologic properties of the biomaterial. A good biomaterial helps in early cell adhesion and cell signaling. In this study, the commercially pure titanium surfaces were prepared to enable machined surfaces to form a control material and to be compared with sandblasted and acid-etched surfaces, laser treated surfaces and titanium dioxide (20 nm) Nano-particle coated surfaces. The surface elements were characterized. The biocompatibility was evaluated by cell culture in vitro using L929 fibroblasts. The results suggested that the titanium dioxide Nano-particle coated surfaces had good osteoconductivity and can be used as a potential method for coating the biomaterial.

  2. Us3 kinase encoded by herpes simplex virus 1 mediates downregulation of cell surface major histocompatibility complex class I and evasion of CD8+ T cells.

    Directory of Open Access Journals (Sweden)

    Takahiko Imai

    Full Text Available Detection and elimination of virus-infected cells by CD8(+ cytotoxic T lymphocytes (CTLs depends on recognition of virus-derived peptides presented by major histocompatibility complex class I (MHC-I molecules on the surface of infected cells. In the present study, we showed that inactivation of the activity of viral kinase Us3 encoded by herpes simplex virus 1 (HSV-1, the etiologic agent of several human diseases and a member of the alphaherpesvirinae, significantly increased cell surface expression of MHC-I, thereby augmenting CTL recognition of infected cells in vitro. Overexpression of Us3 by itself had no effect on cell surface expression of MHC-I and Us3 was not able to phosphorylate MHC-I in vitro, suggesting that Us3 indirectly downregulated cell surface expression of MHC-I in infected cells. We also showed that inactivation of Us3 kinase activity induced significantly more HSV-1-specific CD8(+ T cells in mice. Interestingly, depletion of CD8(+ T cells in mice significantly increased replication of a recombinant virus encoding a kinase-dead mutant of Us3, but had no effect on replication of a recombinant virus in which the kinase-dead mutation was repaired. These results indicated that Us3 kinase activity is required for efficient downregulation of cell surface expression of MHC-I and mediates evasion of HSV-1-specific CD8(+ T cells. Our results also raised the possibility that evasion of HSV-1-specific CD8(+ T cells by HSV-1 Us3-mediated inhibition of MHC-I antigen presentation might in part contribute to viral replication in vivo.

  3. Hybrid silicon honeycomb/organic solar cells with enhanced efficiency using surface etching

    Science.gov (United States)

    Liu, Ruiyuan; Sun, Teng; Liu, Jiawei; Wu, Shan; Sun, Baoquan

    2016-06-01

    Silicon (Si) nanostructure-based photovoltaic devices are attractive for their excellent optical and electrical performance, but show lower efficiency than their planar counterparts due to the increased surface recombination associated with the high surface area and roughness. Here, we demonstrate an efficiency enhancement for hybrid nanostructured Si/polymer solar cells based on a novel Si honeycomb (SiHC) structure using a simple etching method. SiHC structures are fabricated using a combination of nanosphere lithography and plasma treatment followed by a wet chemical post-etching. SiHC has shown superior light-trapping ability in comparison with the other Si nanostructures, along with a robust structure. Anisotropic tetramethylammonium hydroxide etching not only tunes the final surface morphologies of the nanostructures, but also reduces the surface roughness leading to a lower recombination rate in the hybrid solar cells. The suppressed recombination loss, benefiting from the reduced surface-to-volume ratio and roughness, has resulted in a high open-circuit voltage of 600 mV, a short-circuit current of 31.46 mA cm-2 due to the light-trapping ability of the SiHCs, and yields a power conversion efficiency of 12.79% without any other device structure optimization.

  4. Role of hydrogen plasma pretreatment in improving passivation of the silicon surface for solar cells applications.

    Science.gov (United States)

    Wang, Fengyou; Zhang, Xiaodan; Wang, Liguo; Jiang, Yanjian; Wei, Changchun; Sun, Jian; Zhao, Ying

    2014-09-10

    We have investigated the role of hydrogen plasma pretreatment in promoting silicon surface passivation, in particular examining its effects on modifying the microstructure of the subsequently deposited thin hydrogenated amorphous silicon (a-Si:H) passivation film. We demonstrate that pretreating the silicon surface with hydrogen plasma for 40 s improves the homogeneity and compactness of the a-Si:H film by enhancing precursor diffusion and thus increasing the minority carrier lifetime (τ(eff)). However, excessive pretreatment also increases the density of dangling bond defects on the surface due to etching effects of the hydrogen plasma. By varying the duration of hydrogen plasma pretreatment in fabricating silicon heterojunction solar cells based on textured substrates, we also demonstrate that, although the performance of the solar cells shows a similar tendency to that of the τ(eff) on polished wafers, the optimal duration is prolonged owing to the differences in the surface morphology of the substrates. These results suggest that the hydrogen plasma condition must be carefully regulated to achieve the optimal level of surface atomic hydrogen coverage and avoid the generation of defects on the silicon wafer. PMID:25141300

  5. Speciated particle dry deposition to the sea surface: Results from ASEPS '97

    DEFF Research Database (Denmark)

    Pryor, S.C.; Barthelmie, R.J.; Geernaert, L.L.S.;

    1999-01-01

    on Precipitation Scavenging and Atmosphere-Surface Exchange Processes. AMS, Richland, Washington, USA, 12pp.) model to calculate size-segregated dry deposition of particle inorganic nitrogen compounds to the western Baltic during the late Spring of 1997 based on data collected as part of the Air-Sea Exchange......It has been postulated that atmospheric pathways may comprise a significant source of nitrogen for aquatic ecosystems and excess atmospheric deposition to coastal areas may be a major cause of eutrophication. Dry deposition of nitrogen containing particles is a potential, but poorly quantified...... Process Study (ASEPS). The results show that over a 15 d period in April and May dry deposition fluxes varied between 30 and 400 mu g m(-2) d(-1) for nitrate and 1 and 120 mu g m(-2) d(-1) for ammonium. Sensitivity analyses run to assess the potential bounds on actual dry deposition indicate that...

  6. Water Dimers in the Atmosphere II: Results from the VRT(ASP-W)III Potential Surface

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, N; Saykally, R J; Leforestier, C

    2003-10-01

    We report refined results for the equilibrium constant for water dimerization (K{sub P}), computed as a function of temperature via fully-coupled 6-D calculation of the canonical (H{sub 2}O){sub 2} partition function on VRT(ASP-W)III, the most accurate water dimer potential energy surface currently available. Partial pressure isotherms calculated for a range of temperatures and relative humidities indicate that water dimers can exist in sufficient concentrations (e.g., 10{sup 18}m{sup -3} at 30 C and 100% relative humidity) to affect physical and chemical processes in the atmosphere. The determinations of additional thermodynamic properties ({Delta}G, {Delta}H, {Delta}S, C{sub P}, C{sub V}) for (H{sub 2}O){sub 2} are presented, and the role of quasi-bound states in the calculation of K{sub P} is discussed at length.

  7. Cell Surface Display and Characterization of Rhizopus oryzae Lipase in Pichia pastoris Using Sed1p as an Anchor Protein.

    Science.gov (United States)

    Li, Wenqian; Shi, Hao; Ding, Huaihai; Wang, Liangliang; Zhang, Yu; Li, Xun; Wang, Fei

    2015-07-01

    It has been investigated to conduct the surface displaying of lipase from Rhizopus oryzae onto the cells of Pichia pastoris yeast using Sed1p as an anchor protein. A yeast cell surface display plasmid pPICZαA-rol-histag-sed1p was constructed by fusing rol and sed1p gene fragments into the plasmid pPICZαA, followed by introducing recombinant plasmid into P. pastoris cells. Surface display levels were monitored by Western Blot and immunofluorescence microscopy. The activity of displaying lipase obtained from recombinant mutS reached at 60 U/g-dry cell. In addition, the displaying lipase was stable in broad ranges of temperatures and pH, with the optimum temperature at 40 °C and pH 7.5. These results indicate that the P. pastoris displaying lipase may have potential in whole-cell biocatalyst. PMID:26013444

  8. Is there an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors? Part II

    Energy Technology Data Exchange (ETDEWEB)

    Wang Huajie, E-mail: wanghuajie972001@163.com; Sun Yuanyuan; Cao Ying, E-mail: caoying1130@sina.com; Wang Kui; Yang Lin [Henan Normal University, College of Chemistry and Environmental Science (China); Zhang Yidong; Zheng Zhi [Xuchang University, Institute of Surface Micro and Nano Materials (China)

    2012-05-15

    Although nano-structured surfaces exhibit superior biological activities to the smooth or micro-structured surfaces, whether there is an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors is still controversial. In this study, porous aluminum oxide membranes with different pore sizes ranging from 25 to 120 nm were prepared by the anodic oxidation technique. The surface morphology, topography and wettability were analyzed by scanning electron microscope, atomic force microscope and water contact angle measurement, respectively. The results indicated that the synergistic action of the nano-topography structure and hydrophilic/hydrophobic properties resulted in a highest protein adsorption on the aluminum oxide membrane with 80 nm pore size. Additionally, the morphological, metabolic and cell counting methods showed that cells had different sensitivity to porous aluminum oxide membranes with different surface features. Furthermore, this sensitivity was cell type dependent. The optimal pore size of aluminum oxide membranes for cell growth was 80 nm for PC12 cells and 50 nm for NIH 3T3 cells.

  9. Studying the glial cell response to biomaterials and surface topography for improving the neural electrode interface

    Science.gov (United States)

    Ereifej, Evon S.

    Neural electrode devices hold great promise to help people with the restoration of lost functions, however, research is lacking in the biomaterial design of a stable, long-term device. Current devices lack long term functionality, most have been found unable to record neural activity within weeks after implantation due to the development of glial scar tissue (Polikov et al., 2006; Zhong and Bellamkonda, 2008). The long-term effect of chronically implanted electrodes is the formation of a glial scar made up of reactive astrocytes and the matrix proteins they generate (Polikov et al., 2005; Seil and Webster, 2008). Scarring is initiated when a device is inserted into brain tissue and is associated with an inflammatory response. Activated astrocytes are hypertrophic, hyperplastic, have an upregulation of intermediate filaments GFAP and vimentin expression, and filament formation (Buffo et al., 2010; Gervasi et al., 2008). Current approaches towards inhibiting the initiation of glial scarring range from altering the geometry, roughness, size, shape and materials of the device (Grill et al., 2009; Kotov et al., 2009; Kotzar et al., 2002; Szarowski et al., 2003). Literature has shown that surface topography modifications can alter cell alignment, adhesion, proliferation, migration, and gene expression (Agnew et al., 1983; Cogan et al., 2005; Cogan et al., 2006; Merrill et al., 2005). Thus, the goals of the presented work are to study the cellular response to biomaterials used in neural electrode fabrication and assess surface topography effects on minimizing astrogliosis. Initially, to examine astrocyte response to various materials used in neural electrode fabrication, astrocytes were cultured on platinum, silicon, PMMA, and SU-8 surfaces, with polystyrene as the control surface. Cell proliferation, viability, morphology and gene expression was measured for seven days in vitro. Results determined the cellular characteristics, reactions and growth rates of astrocytes

  10. Lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria

    OpenAIRE

    Muscariello Lidia; Boekhorst Jos; Siezen Roland; Molenaar Douwe; Renckens Bernadet; Kleerebezem Michiel

    2006-01-01

    Abstract Background Genomes of gram-positive bacteria encode many putative cell-surface proteins, of which the majority has no known function. From the rapidly increasing number of available genome sequences it has become apparent that many cell-surface proteins are conserved, and frequently encoded in gene clusters or operons, suggesting common functions, and interactions of multiple components. Results A novel gene cluster encoding exclusively cell-surface proteins was identified, which is ...

  11. Effect of surface treatments of titanium on amphotericin B-treated Candida albicans persister cells

    OpenAIRE

    Tsang, CSP; Tang, DYK

    2010-01-01

    Although persister cells in Candida albicans biofilm may contribute to its increased resistance to antifungal drugs, little information is available on the formation of Candida persister cells on titanium surfaces. The effect of different surface treatments of Ti on persister cells was determined in the present study. Titanium discs were surface-treated by three different methods (Group A - polishing, Group B - sandblasting followed by acid-etching, and Group C - sandblasting alone). Persiste...

  12. Three-Dimensional Tissue Models Constructed by Cells with Nanometer- or Micrometer-Sized Films on the Surfaces.

    Science.gov (United States)

    Liu, Chun-Yen; Matsusaki, Michiya; Akashi, Mitsuru

    2016-04-01

    Living tissues or organ modules consist of different types of highly organized cells and extracellular matrices (ECMs) in a hierarchical manner, such as the multilayered structure of blood vessels and the radial structures of hepatic lobules. Due to animal examinations being banned in the EU since 2013 and a shortage in the demand for tissue repair or organ transplantation, the creation of artificial 3D tissues possessing specific structures and functions similar to natural tissues are key challenges in tissue engineering. To date, we have developed a simple but unique bottom-up approach, a hierarchical cell manipulation technique, with a nanometer-sized ECM matrix consisting of fibronectin (FN) and gelatin (G) on cell surfaces. About 10 nm thick FN/G ECM films on cell surfaces were coated successfully by using layer-by-layer coating methodology. Various 3D constructs with higher cell density with different types of cells were successfully constructed. In addition to the construction of tissues with higher cell densities, other tissues, such as cartilage or skin tissues, with different cell densities are also important tissue models for tissue engineering and pharmaceutical industries. Thus, we recently developed other methodologies, the collagen coating method and multiple coating method, to fabricate micrometer-sized level ECM layers on cell surfaces. Various micro- or millimeter-sized 3D constructs with lower cell densities were constructed successfully. By using these two methods, cell distances in 2D or 3D views can be controlled by different thicknesses of ECM layers on cell surfaces at the single-cell level. Both FN/G and the collagen coating method resulted in homogenous 3D tissues with a controlled layer numbers, cell type, cell location, and properties; these will be promising to achieve different goals in tissue engineering. PMID:26924465

  13. CD26 surface molecule involvement in T cell activation and lymphokine synthesis in rheumatoid and other inflammatory synovitis.

    Science.gov (United States)

    Gerli, R; Muscat, C; Bertotto, A; Bistoni, O; Agea, E; Tognellini, R; Fiorucci, G; Cesarotti, M; Bombardieri, S

    1996-07-01

    T cell surface expression and the functional role of CD26 antigen (Ag), a surface ectoenzyme involved in T cell activation and migration across the extracellular matrix, were analyzed in the peripheral blood (PB) and synovial fluid (SF) from patients with inflammatory arthritides. CD26 membrane expression on T cells was detected by cytofluorometry using two different monoclonal antibodies, anti-Ta1 and anti-1F7, while cell proliferation and both IL-2 and IFN-gamma production were evaluated in anti-CD3- or anti-CD2-stimulated cell cultures after Ag surface modulation with anti-1F7. The results showed that Ta1 and 1F7 Ag expression were increased on T cells from PB of patients with active, but not inactive, rheumatoid arthritis (RA). Most SF T cells from RA or other inflammatory arthritides displayed the memory marker CD45R0 and the Ta1 Ag, but lacked the 1F7 molecule. In addition, in vitro 1F7 modulation, which enhanced RA PB T cell proliferation and both IL-2 and IFN-gamma synthesis, did not synergize with anti-CD3 or anti-CD2 in inducing IL-2-dependent activation of SF T cells, but reduced IFN-gamma production. A spontaneous reappearance of 1F7 Ag on the SF T cell surface was seen after 2-5 days in culture. Phorbol myristate acetate, able to accelerate its reexpression, also restored a normal response of SF T cells to anti-1F7 comitogenic effects. These data confirm a role of the CD26 surface molecule in regulating T cell activation and lymphokine synthesis. This observation may have important implications in the regulation of T cell activity at the joint level during chronic inflammatory processes. PMID:8674237

  14. Modeling of Surface Reflectance of Acid Textured Multicrystalline Silicon Wafer for Solar Cell Application

    Directory of Open Access Journals (Sweden)

    Firoz Khan

    2013-06-01

    Full Text Available This paper deals with the theoretical modeling of surface reflectance of acid textured multicrystalline wafer used in the processing of solar cell to minimize the surface reflectivity and there by enhancing the efficiency of the cell without wasting the wafers and time in optimizing the texturization process for the development of high efficiency solar cell. In the present study, texturization of mc-Si has been carried out in acidic solution using different compositions of HF, HNO3 and H3PO4 at different temperatures and for varying etching time (45-195 s. The best results were obtained for wet acidic ice cooled solution of HF:HNO3:H3PO4 :: 10:1:5 when textured for 165 s. Attempts have been made to explain the reflectivity behavior of the textured surfaces of the mc-Si wafers on the basis of the scanning electron microscopic (SEM micrographs and theoretical modeling of reflectivity assuming the textured surface as a part of a hemisphere. It was observed that the average experimental reflectivity decreases as the etching time increases from 45 s to 165 s and attains a minimum value of 18% for the etching time of 165 s. The experimental reflectivity curve for the etching time of 165 s matches very well with the calculated reflectivity curve for h/D ratio of 0.50 in the wavelength range of 700-1050nm. These techniques are seems to be useful for large area industrial solar cell applications and the developed theoretical modeling software package may be suitably used for optimizing the texturization parameters of mc-Si wafers for achieving the minimal reflectance values for increasing the efficiency of solar cell.

  15. Application of the MOS-C-V technique to determine impurity concentrations and surface parameters on the diffused face of silicon solar cells

    Science.gov (United States)

    Weinberg, I.

    1975-01-01

    The feasibility of using the MOS C-V technique to obtain information regarding impurity and surface state concentrations on the diffused face of silicon solar cells with Ta2O5 coatings is studied. Results indicate that the MOS C-V technique yields useful information concerning surface parameters which contribute to the high, efficiency limiting, surface recombination velocities on the n+ surface of silicon solar cells.

  16. Test results and supporting analysis of a near-surface heater experiment in the Eleana argillite

    International Nuclear Information System (INIS)

    A preliminary evaluation of the in-situ thermomechanical response of argillite to heating was obtained from a near-surface heater test in the Eleana Formation, at the United States Department of Energy, Nevada Test Site. The experiment consisted of a 3.8 kW, 3-m long x 0.3-m diameter electrical heater in a central hole surrounded by peripheral holes containing instrumentation to measure temperature, gas pressures, and vertical displacement. A thermal model of the experiment agreed well with experimental results; a comparison of measured and predicted temperatures indicates that some nonmodeled vertical transport of water and water vapor occurred near the heater, especially at early times. A mechanical model indicated that contraction of expandable clays in the argillite produced a region 1.5 - 2.0 m in radius, in which opening of preexisting joints occurred as a result of volumetric contraction. Results of thermal and mechanical modeling, laboratory property measurements, experimental temperature measurements, and post-test observations are all self-consistent and provide preliminary information on the in-situ response of argillaceous rocks to the emplacement of heat-producing nuclear waste

  17. A surgical robot with a heart-surface-motion synchronization mechanism for myoblast cell sheet transplantation.

    Science.gov (United States)

    Xu, Kangyi; Nakamura, Ryoichi

    2013-01-01

    Myoblast cell sheets are employed in the clinical treatment of heart disorders. We propose a surgical robot system with two endoscopic cameras, characterized by a double remote center of motion (RCM) mechanism, to realize heart-surface-motion synchronization movement for myoblast cell sheet transplantation on a beating heart surface. A robot system with the double RCM mechanism was developed for which the linear and rotation motions are totally isolated, and an experiment was conducted to evaluate the tracking accuracy of the robot system when tracking a randomly moving target. The tracking data were updated with a Polaris system at 30 Hz. The experiment results showed linear and rotation tracking errors of 4.93 ± 5.92 mm and 2.54 ± 5.44°, respectively.

  18. The discrete dipole approximation with surface interaction for evanescent wave-based characterization of nanostructures on a surface with validation against experimental results

    Science.gov (United States)

    Short, Mitchell R.

    Nanotechnology has become so widely used it can be found in every aspect of life, from cell-phones and computers, to cars, and even athletic socks. As it permeates so many markets, the need for supplemental technologies has also increased. One such needed technology is in the area of nanoscale characterization. Current imaging methods are advanced; however, they do not have the capabilities to characterize the size, shape, composition, and arrangement of nanostructures and nanoparticles in a real-time, unobtrusive manner. The Polarized-Surface-Wave-Scattering system (PSWSS) is a method being researched at the University of Utah that can provide such characterization, although in order for the PSWSS to function accurately through inversion techniques, a predictive forward model must be developed and validated. This work explores the discrete dipole approximation with surface interaction (DDA-SI), an open source MATLAB toolbox, as a predictive model to calculate electromagnetic scattering by objects on a surface illuminated by an evanescent wave generated by total internal reflection (TIR). Far-field scattering predictions via DDA-SI are validated against scaled microwave experimental results for two objects on a surface: a sphere with a diameter of lambda/1.92 and a cube with a side length of lambda/1.785, where lambda refers to the wavelength. A good agreement between experiments and simulations is observed, especially when modified Fresnel reflection coefficients are employed by DDA-SI. Programs to calculate the amplitude scattering matrix and Mueller matrix elements have been also been created. Additionally, the sensitivity of four Mueller matrix elements (M11, M12, M21, and M22) to the particle size, material (gold and silver), shape (sphere and cube), and interparticle spacing, is analyzed. It is found that these four elements are sensitive to changes in shape and interparticle spacing, whereas prove insufficient to difference in material and sizes smaller than

  19. Surface Expression of Precursor N-cadherin Promotes Tumor Cell Invasion

    Directory of Open Access Journals (Sweden)

    Deborah Maret

    2010-12-01

    Full Text Available The expression of N-cadherin (NCAD has been shown to correlate with increased tumor cell motility and metastasis. However, NCAD-mediated adhesion is a robust phenomenon and therefore seems to be inconsistent with the “release” from intercellular adhesion required for invasion. We show that in the most invasive melanoma and brain tumor cells, altered posttranslational processing results in abundant nonadhesive precursor N-cadherin (proNCAD at the cell surface, although total NCAD levels remain constant. We demonstrate that aberrantly processed proNCAD promotes cell migration and invasion in vitro. Furthermore, in human tumor specimens, we find high levels of proNCAD as well, supporting an overall conclusion that proNCAD and mature NCAD coexist on these tumor cell surfaces and that it is the ratio between these functionally antagonistic moieties that directly correlates with invasion potential. Our work provides insight into what may be a widespread mechanism for invasion and metastasis and challenges the current dogma of the functional roles played by classic cadherins in tumor progression.

  20. A Quantitative Perspective on Surface Marker Selection for the Isolation of Functional Tumor Cells.

    Science.gov (United States)

    Cahall, Calvin F; Lilly, Jacob L; Hirschowitz, Edward A; Berron, Brad J

    2015-01-01

    Much effort has gone into developing fluid biopsies of patient peripheral blood for the monitoring of metastatic cancers. One common approach is to isolate and analyze tumor cells in the peripheral blood. Widespread clinical implementation of this approach has been hindered by the current choice of targeting epithelial markers known to be highly variable in primary tumor sites. Here, we review current antigen-based tumor cell isolation strategies and offer biological context for commonly studied cancer surface markers. Expression levels of the most common markers are quantitated for three breast cancer and two non-small cell lung cancer (NSCLC) lineage models. These levels are contrasted with that present on healthy peripheral blood mononuclear cells (PBMC) for comparison to expected background levels in a fluid biopsy setting. A key feature of this work is establishing a metric of markers per square micrometer. This describes an average marker density on the cell membrane surface, which is a critical metric for emerging isolation strategies. These results serve to extend expression of key tumor markers in a sensitive and dynamic manner beyond traditional positive/negative immunohistochemical staining to guide future fluid biopsy targeting strategies. PMID:26309407

  1. Small lytic peptides escape the inhibitory effect of heparan sulfate on the surface of cancer cells

    Directory of Open Access Journals (Sweden)

    Lindin Inger

    2011-03-01

    Full Text Available Abstract Background Several naturally occurring cationic antimicrobial peptides (CAPs, including bovine lactoferricin (LfcinB, display promising anticancer activities. These peptides are unaffected by multidrug resistance mechanisms and have been shown to induce a protective immune response against solid tumors, thus making them interesting candidates for developing novel lead structures for anticancer treatment. Recently, we showed that the anticancer activity by LfcinB was inhibited by the presence of heparan sulfate (HS on the surface of tumor cells. Based on extensive structure-activity relationship studies performed on LfcinB, shorter and more potent peptides have been constructed. In the present study, we have investigated the anticancer activity of three chemically modified 9-mer peptides and the influence of HS and chondroitin sulfate (CS on their cytotoxic activity. Methods Various cell lines and red blood cells were used to investigate the anticancer activity and selectivity of the peptides. The cytotoxic effect of the peptides against the different cell lines was measured by use of a colorimetric MTT viability assay. The influence of HS and CS on their cytotoxic activity was evaluated by using HS/CS expressing and HS/CS deficient cell lines. The ability of soluble HS and CS to inhibit the cytotoxic activity of the peptides and the peptides' affinity for HS and CS were also investigated. Results The 9-mer peptides displayed selective anticancer activity. Cells expressing HS/CS were equally or more susceptible to the peptides than cells not expressing HS/CS. The peptides displayed a higher affinity for HS compared to CS, and exogenously added HS inhibited the cytotoxic effect of the peptides. Conclusions In contrast to the previously reported inhibitory effect of HS on LfcinB, the present study shows that the cytotoxic activity of small lytic peptides was increased or not affected by cell surface HS.

  2. A network of autonomous surface ozone monitors in Antarctica: technical description and first results

    Directory of Open Access Journals (Sweden)

    S. J.-B. Bauguitte

    2010-12-01

    Full Text Available A suite of 10 autonomous ozone monitors, each powered using renewable energy, was developed and built to study surface ozone in Antarctica during the International Polar Year (2007–2009. The monitoring systems were deployed in a network around the Weddell Sea sector of coastal Antarctica with a transect up onto the Antarctic Plateau. The aim was to measure for a full year, thus gaining a much-improved broader view of boundary layer ozone seasonality at different locations as well as of factors affecting the budget of surface ozone in Antarctica. Ozone mixing ratios were measured based on UV photometry using a modified version of the commercial 2B Technologies Inc. Model 202 instrument. All but one of the autonomous units measured successfully within its predefined duty cycle throughout the year, with some differences in performance dependent on power availability and ambient temperature. Mean data recovery after removal of outliers was on average 70% (range 44–83% and precision varied between 1.5 and 8 ppbv, thus was sufficiently good to resolve year-round the main ozone features of scientific interest. We conclude that, with adequate power, and noting a minor communication problem, our units would be able to operate successfully at ambient temperatures down to −60 °C. Systems such as the one described in this paper, or derivatives of it, could therefore be deployed either as local or regional networks elsewhere in the Arctic or Antarctic. Here we present technical information and first results from the experiment.

  3. A network of autonomous surface ozone monitors in Antarctica: technical description and first results

    Directory of Open Access Journals (Sweden)

    S. J.-B. Bauguitte

    2011-04-01

    Full Text Available A suite of 10 autonomous ozone monitoring units, each powered using renewable energy, was developed and built to study surface ozone in Antarctica during the International Polar Year (2007–2009. The monitoring systems were deployed in a network around the Weddell Sea sector of coastal Antarctica with a transect up onto the Antarctic Plateau. The aim was to measure for a full year, thus gaining a much-improved broader view of boundary layer ozone seasonality at different locations as well as of factors affecting the budget of surface ozone in Antarctica. Ozone mixing ratios were measured based on UV photometry using a modified version of the commercial 2B Technologies Inc. Model 202 instrument. All but one of the autonomous units measured successfully within its predefined duty cycle throughout the year, with some differences in performance dependent on power availability and ambient temperature. Mean data recovery after removal of outliers was on average 70% (range 44–83% and precision varied between 1.5 and 8 ppbv, thus was sufficiently good to resolve year-round the main ozone features of scientific interest. We conclude that, with adequate power, and noting a minor communication problem, our units would be able to operate successfully at ambient temperatures down to −60 °C. Systems such as the one described in this paper, or derivatives of it, could therefore be deployed either as local or regional networks elsewhere in the Arctic or Antarctic. Here we present technical information and first results from the experiment.

  4. The use of scFv-displaying yeast in mammalian cell surface selections.

    Science.gov (United States)

    Wang, Xin Xiang; Shusta, Eric V

    2005-09-01

    Yeast surface display has proven to be a powerful tool for the directed evolution of immunological proteins when soluble ligands are available (Cho, B.K., Kieke, M.C., Boder, E.T., Wittrup, K.D., Kranz, D.M., 1998. A yeast surface display system for the discovery of ligands that trigger cell activation. J. Immunol. Methods 220, 179; Boder, E.T., Midelfort, K.S., Wittrup, K.D., 2000. Directed evolution of antibody fragments with monovalent femtomolar antigen-binding affinity. Proc. Natl. Acad. Sci. U. S. A. 97, 10701; Shusta, E.V., Holler, P.D., Kieke, M.C., Kranz, D.M., Wittrup, K.D., 2000. Directed evolution of a stable scaffold for T-cell receptor engineering. Nat. Biotechnol. 18, 754; Esteban, O., Zhao, H., 2004. Directed evolution of soluble single-chain human class II MHC molecules. J. Mol. Biol. 340, 81). This investigation extends the utility of this display platform by demonstrating its capacity for use in cell panning selections. This was accomplished by employing a model single-chain antibody (scFv)-hapten system that allowed for detailed investigation of the factors governing panning success. Yeast displaying anti-fluorescein scFv (4-4-20) exhibited specific interactions with the fluoresceinated endothelial cells and could be recovered from large backgrounds of irrelevant yeast in just three rounds. Successful selections required as few as 1700 fluorescein ligands per cell, and a three-round enrichment ratio of 10(6) was possible. These results indicate that yeast surface display is a viable option for use in cell or tissue-based selections.

  5. Instability of surface lenticular vortices: results from laboratory experiments and numerical simulations

    Science.gov (United States)

    Lahaye, Noé; Paci, Alexandre; Smith, Stefan Llewellyn

    2016-04-01

    We examine the instability of lenticular vortices -- or lenses -- in a stratified rotating fluid. The simplest configuration is one in which the lenses overlay a deep layer and have a free surface, and this can be studied using a two-layer rotating shallow water model. We report results from laboratory experiments and high-resolution direct numerical simulations of the destabilization of vortices with constant potential vorticity, and compare these to a linear stability analysis. The stability properties of the system are governed by two parameters: the typical upper-layer potential vorticity and the size (depth) of the vortex. Good agreement is found between analytical, numerical and experimental results for the growth rate and wavenumber of the instability. The nonlinear saturation of the instability is associated with conversion from potential to kinetic energy and weak emission of gravity waves, giving rise to the formation of coherent vortex multipoles with trapped waves. The impact of flow in the lower layer is examined. In particular, it is shown that the growth rate can be strongly affected and the instability can be suppressed for certain types of weak co-rotating flow.

  6. Biodegradation and surfactant-mediated biodegradation of diesel fuel by 218 microbial consortia are not correlated to cell surface hydrophobicity

    Energy Technology Data Exchange (ETDEWEB)

    Owsianiak, Mikolaj; Szulc, Alicja; Chrzanowski, Lukasz; Bogacki, Mariusz [Poznan Univ. of Technology (Poland). Inst. of Chemical Technology and Engineering; Cyplik, Pawel; Olejnik-Schmidt, Agniezka K. [Poznan Univ. of Life Sciences (Poland). Dept. of Biotechnology and Food Microbiology; Heipieper, Hermann J. [Helmholtz Centre for Environmental Research - UFZ, Leipzig (Germany). Dept. of Environmental Biotechnology

    2009-09-15

    In this study, we elucidated the role of cell surface hydrophobicity (microbial adhesion to hydrocarbons method, MATH) and the effect of anionic rhamnolipids and nonionic Triton X-100 surfactants on biodegradation of diesel fuel employing 218 microbial consortia isolated from petroleum-contaminated soils. Applied enrichment procedure with floating diesel fuel as a sole carbon source in liquid cultures resulted in consortia of varying biodegradation potential and diametrically different cell surface properties, suggesting that cell surface hydrophobicity is a conserved parameter. Surprisingly, no correlations between cell surface hydrophobicity and biodegradation of diesel fuel were found. Nevertheless, both surfactants altered cell surface hydrophobicity of the consortia in similar manner: increased for the hydrophilic and decreased for the hydrophobic cultures. In addition to this, the surfactants exhibited similar influence on diesel fuel biodegradation: Increase was observed for initially slow-degrading cultures and the opposite for fast degraders. This indicates that in the surfactant-mediated biodegradation, effectiveness of surfactants depends on the specification of microorganisms and not on the type of surfactant. In contrary to what was previously reported for pure strains, cell surface hydrophobicity, as determined by MATH, is not a good descriptor of biodegrading potential for mixed cultures. (orig.)

  7. Enhanced compatibility of chemically modified titanium surface with periodontal ligament cells

    Science.gov (United States)

    Kado, T.; Hidaka, T.; Aita, H.; Endo, K.; Furuichi, Y.

    2012-12-01

    A simple chemical modification method was developed to immobilize cell-adhesive molecules on a titanium surface to improve its compatibility with human periodontal ligament cells (HPDLCs).The polished titanium disk was immersed in 1% (v/v) p-vinylbenzoic acid solution for 2 h to introduce carboxyl groups onto the surface. After rinsing with distilled deionized water, the titanium disk was dipped into 1.47% 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide solution containing 0.1 mg/ml Gly-Arg-Gly-Asp-Ser (GRGDS), human plasma fibronectin (pFN), or type I collagen from calf skin (Col) to covalently immobilize the cell-adhesive molecules on the titanium surface via formation of peptide bonds. X-ray photoelectron spectroscopy analyses revealed that cell-adhesive molecules were successfully immobilized on the titanium surfaces. The Col-immobilized titanium surface revealed higher values regarding nano rough characteristics than the as-polished titanium surface under scanning probe microscopy. The number of HPDLCs attached to both the pFN- and Col-immobilized titanium surfaces was twice that attached to the as-polished titanium surfaces. The cells were larger with the cellular processes that stretched to a greater extent on the pFN- and Col-immobilized titanium surfaces than on the as-polished titanium surface (p < 0.05). HPDLCs on the Col-immobilized titanium surfaces showed more extensive expression of vinculin at the tips of cell projections and more contiguously along the cell outline than on the as-polished, GRGDS-immobilized and pFN-immobilized titanium surfaces. It was concluded that cell-adhesive molecules successfully immobilized on the titanium surface and improved the compatibility of the surface with HPDLCs. The Col-immobilized titanium surface could be used for forming ligament-like tissues around titanium dental implants.

  8. Exocellular esterase and emulsan release from the cell surface of Acinetobacter calcoaceticus.

    OpenAIRE

    Shabtai, Y; Gutnick, D L

    1985-01-01

    An esterase activity has been found, both in the cell-free growth medium and on the cell surface of the hydrocarbon-degrading Acinetobacter calcoaceticus RAG-1. The enzyme catalyzed the hydrolysis of acetyl and other acyl groups from triglycerides and aryl and alkyl esters. Emulsan, the extracellular heteropolysaccharide bioemulsifier produced by strain RAG-1, was also a substrate for the enzyme. Gel filtration showed that the cell-free enzyme was released from the cell surface either emulsan...

  9. Cassini results on Titan's atmospheric and surface properties changes since the northern equinox

    Science.gov (United States)

    Coustenis, Athena; Drossart, Pierre; Flasar, F. Michael; Achterberg, Richard K.; Rodriguez, Sebastien; Nixon, Conor; Bampasidis, Georgios; Solomonidou, Anezina; Jennings, Donald; Lavvas, Panayiotis

    2016-07-01

    Since 2010, we observe the set in and enhancement at Titan's south pole of several trace species, such as HC3N and C6H6, observed only at high northern latitudes before equinox. We will present an analysis of spectra acquired by Cassini/CIRS at high resolution from 2012 in nadir mode. We investigated here several latitudes of 70°S to 70°N since 2010 (after the Southern Autumnal Equinox) until end of 2014 [1]. For some of the most abundant and longest-lived hydrocarbons (C2H2, C2H6 and C3H8) and CO2, the evolution in the past 4 years at a given latitude is not very significant within error bars especially until mid-2013 [1]. In more recent dates, these molecules show a dramatic trend for increase in the south. The 70°S and 50°S or mid-latitudes show different behavior demonstrating that they are subject to different dynamical processes in and out of the polar vortex region. For most species, we find higher abundances at 50°N compared to 50°S, with the exception of C3H8, CO2, C6H6 and HC3N, which arrive at similar mixing ratios after mid-2013 [1]. While the 70°N data show generally no change with a trend rather to a small decrease for most species within 2014, the 70°S results indicate a strong enhancement in trace stratospheric gases after 2012. In particular, HC3N, HCN and C6H6 have increased by 3 orders of magnitude over the past 3-4 years while other molecules, including C2H4, C3H4 and C4H2, have increased less sharply (by 1-2 orders of magnitude). This is a strong indication of the rapid and sudden buildup of the gaseous inventory in the southern stratosphere during 2013-2014, as expected as the pole moves deeper into winter shadow. Subsidence gases that accumulate in the absence of ultraviolet sunlight, evidently increased quickly since 2012 and some of them may be responsible also for the reported haze decrease in the north and its appearance in the south at the same time [2]. Clearly Titan is a dynamic system with indications of short and long

  10. Epidemic Keratoconjunctivitis-Causing Adenoviruses Induce MUC16 Ectodomain Release To Infect Ocular Surface Epithelial Cells.

    Science.gov (United States)

    Menon, Balaraj B; Zhou, Xiaohong; Spurr-Michaud, Sandra; Rajaiya, Jaya; Chodosh, James; Gipson, Ilene K

    2016-01-01

    Human adenoviruses (HAdV), species D in particular (HAdV-D), are frequently associated with epidemic keratoconjunctivitis (EKC). Although the infection originates at the ocular surface epithelium, the mechanisms by which HAdV-Ds bypass the membrane-associated mucin (MAM)-rich glycocalyx of the ocular surface epithelium to trigger infection and inflammation remain unknown. Here, we report that an EKC-causing adenovirus (HAdV-D37), but not a non-EKC-causing one (HAdV-D19p), induces ectodomain release of MUC16-a MAM with barrier functions at the ocular surface-from cultured human corneal and conjunctival epithelial cells. HAdV-D37, but not HAdV-D19p, is also found to decrease the glycocalyx barrier function of corneal epithelial cells, as determined by rose bengal dye penetrance assays. Furthermore, results from quantitative PCR (qPCR) amplification of viral genomic DNA using primers specific to a conserved region of the E1B gene show that, in comparison to infection by HAdV-D19p, infection by HAdV-D37 is significantly increased in corneal epithelial cells. Collectively, these results point to a MUC16 ectodomain release-dependent mechanism utilized by the EKC-causing HAdV-D37 to initiate infection at the ocular surface. These findings are important in terms of understanding the pathogenesis of adenoviral keratoconjunctivitis. Similar MAM ectodomain release mechanisms may be prevalent across other mucosal epithelia in the body (e.g., the airway epithelium) that are prone to adenoviral infection. IMPORTANCE Human adenoviruses (HAdVs) are double-stranded DNA viruses that cause infections across all mucosal tissues in the body. At the ocular surface, HAdVs cause keratoconjunctivitis (E. Ford, K. E. Nelson, and D. Warren, Epidemiol Rev 9:244-261, 1987, and C. M. Robinson, D. Seto, M. S. Jones, D. W. Dyer, and J. Chodosh, Infect Genet Evol 11:1208-1217, 2011, doi:10.1016/j.meegid.2011.04.031)-a highly contagious infection that accounts for nearly 60% of conjunctivitis cases

  11. Lectin binding profiles of SSEA-4 enriched, pluripotent human embryonic stem cell surfaces

    Directory of Open Access Journals (Sweden)

    Shin Soojung

    2005-07-01

    Full Text Available Abstract Background Pluripotent human embryonic stem cells (hESCs have the potential to form every cell type in the body. These